cssi/SciSciGPT-SciSciNet huggingface dataset:
Closed-form effects of warping and pretwist on the torsional vibration of thin-walled open-profile cantilevers

Abstract Theoretical natural frequencies are determined for the first three modes of torsional vibration of pretwisted cantilevers with thin-walled open profiles. The equation of motion and boundary conditions are derived from a multifilament model of a pretwisted thin-walled bar undergoing warp deformation and a moderately large twist about the elastic axis. Closed-form torsional frequencies and mode shapes are derived from the linear terms of the resulting nonlinear equations. As the length-to-leg ratio ( L/b ) and leg-to-thickness ratio ( b/t ) of typical open-profile cantilevers are varied, the individual and collective effects of warping and pretwist on the torsional frequencies are qualitatively defined. The refined derivation and closed-form solutions presented here reveal significant destiffening of the torsional frequencies due to warping-pretwist coupling in cantilevers having pretwisted unsymmetrical open-profiles. These coupling effects, which have been ignored in thin-walled bar vibration theories heretofore, are brought out by the Wagner effect and warping shear stresses acting on the profile.
Waring's number mod m

Abstract Let p be an odd prime and γ ( k , p n ) be the smallest positive integer s such that every integer is a sum of s kth powers ( mod p n ) . We establish γ ( k , p n ) ⩽ [ k / 2 ] + 2 and γ ( k , p n ) ≪ k provided that k is not divisible by ( p − 1 ) / 2 . Next, let t = ( p − 1 ) / ( p − 1 , k ) , and q be any positive integer. We show that if ϕ ( t ) ⩾ q then γ ( k , p n ) ⩽ c ( q ) k 1 / q for some constant c ( q ) . These results generalize results known for the case of prime moduli. Video abstract For a video summary of this paper, please visit http://www.youtube.com/watch?v=zpHYhwL1kD0 .
Effects of high energy boron ions implanted in MOSFETs

Abstract In recent years, high energy ion implantation has been found to be very attractive for device fabrication because of its ability to place dopants more than 1 μm beneath the substrate's surface. Many new applications and structures are made possible with this feature. Examples are the replacement of epilayer growth by high energy ion implant to form bipolar transistor subcollectors [1] and the construction of retrograded wells to reduce latchup and soft-error in CMOS transistors [2,3]. In this work, we will investigate the feasibility of customizing integrated circuits by threshold adjustment implant as a late processing step. Different doses of boron ions with energies ranging from 0.75 to 0.90 MeV are implanted into n-MOSFETs after second-level poly-Si deposition. Rapid thermal annealing is used for postimplant annealing and dopant activation. For low-dose implants, full activation can be realized at about 750°C for 15 s. For high-dose implants, however, no full activation is seen even at 1000°C. I-V measurements are used to investigate the high-energy implantation effects on the threshold voltage, the channel leakage current, and the subthreshold slope of the MOSFET transistors. It is found that the threshold voltage shifts are no longer linearly proportional to the implant doses. A new relationship is presented. After annealing, the leakage current for the implanted transistors can be reduced to the same level as that of unimplanted devices. However, the subthreshold slope is larger for an implanted transistor compared to an unimplanted transistor.
An Alternative Technique for Mandibular Advancement Prosthesis Fabrication

One of the conservative and successful modalities of treatment for obstructive sleep apnea is the mandibular advancement prosthesis. This prosthesis engages teeth on both dental arches for retention and stability. This article describes a technique that allows that fabrication of such a prosthesis in one piece and in a single laboratory step. This may be beneficial in reducing the laboratory time required for fabrication of such a prosthesis.
Effect of dispersion techniques on thermal and mechanical properties of phenolic/E-glass nanocomposites

Phenolic resin was modified using nanoclay to improve flammability/thermal properties. High-shear and planetary centrifugal (PC) mixing techniques were used to blend nanoclay into phenolic. This was followed by vacuum-assisted resin transfer molding to manufacture glass-reinforced nanocomposites. Loadings of 2.5, 5.0, and 7.5 wt% of nanoclay were processed using both techniques. The degree of dispersion was analyzed using scanning electron microscope and transmission electron microscope. Flammability/thermal property was evaluated using mass loss calorimeter. Mechanical properties such as flexural strength and modulus, compressive strength, interlaminar shear strength, and tensile strength and modulus were evaluated. It is concluded that the cost-effective PC mixing technique can be used in manufacturing nanocomposites to enhance flammability/thermal property without sacrificing mechanical properties.
The fine structure of the ovary of the feather star Nemaster rubiginosa (Echinodermata: Crinoidea).

The fine structure of all the constituent cell type of the crinoid axial organ is described (coelomic epithelial cells, muscles, free cells, gland cells and neurons) ; also described is the fine structure of the extracellular haemal fluid. The gland cells of the glandular tubules of the axial organ have the characteristic fine structure of protein exporting cells and may produce granular and filamentous components of the haemal fluid. The neurons (perikarya and axons) of the axial organ may possibly be neurosecretory, since they are filled with electron-dense granules. Homologies between the axial organs of different echinoderm classes are discussed.
Lung cancer prevention: the guidelines

Lung carcinogenesis is a chronic and multi-step process resulting in malignant lung tumors. This progression from normal to neoplastic pulmonary cells or tissues could be arrested or reversed through pharmacologic treatments, which are known as cancer chemoprevention. These therapeutic interventions should reduce or avoid the clinical consequences of lung cancer by treating early neoplastic lesions before the development of clinically evident signs or symptoms of malignancy. Preclinical, clinical, and epidemiologic findings relating to different classes of candidate chemopreventive agents provide strong support for lung cancer prevention as an attractive therapeutic strategy. Smoking prevention and smoking cessation represent an essential approach to reduce the societal impact of tobacco carcinogenesis. However, even if all the goals of the national antismoking efforts were met, there still would be a large population of former smokers who would be at increased risk for lung cancers. Lung cancer also can occur in those persons who never have smoked. This article focuses on what is now known about pharmacologic strategies for lung cancer prevention. Randomized clinical trials using β-carotene, retinol, isotretinoin or N-acetyl-cysteine did not show benefit for primary and tertiary lung cancer prevention. There is also evidence that the use of β-carotene and isotretinoin for lung cancer chemoprevention in high-risk individuals may increase the risk for lung cancer, especially in individuals who continue to smoke. There is a need for relevant in vitro models to identify pathways that activate chemopreventive effects in the lung. An improved understanding of cancer prevention mechanisms should aid in the design of clinical trials and in the validation of candidate chemopreventive targets as well as the discovery of new targets. Until such studies are completed, no agent or combination of agents should be used for lung cancer prevention outside of a clinical trial.
IMIRS: a high-resolution 3D reconstruction package integrated with a relational image database.

Recent advances in electron cryomicroscopy instrumentation and single particle reconstruction have created opportunities for high-throughput and high-resolution three-dimensional (3D) structure determination of macromolecular complexes. However, it has become impractical and inefficient to rely on conventional text file data management and command-line programs to organize and process the increasing numbers of image data required in high-resolution studies. Here, we present a distributed relational database for managing complex datasets and its integration into our high-resolution software package IMIRS (Image Management and Icosahedral Reconstruction System). IMIRS consists of a complete set of modular programs for icosahedral reconstruction organized under a graphical user interface and provides options for user-friendly, step-by-step data processing as well as automatic reconstruction. We show that the integration of data management with processing in IMIRS automates the tedious tasks of data management, enables data coherence, and facilitates information sharing in a distributed computer and user environment without significantly increasing the time of program execution. We demonstrate the applicability of IMIRS in icosahedral reconstruction toward high resolution by using it to obtain an 8-A 3D structure of an intermediate-sized dsRNA virus.
Role of endonuclease G in neuronal excitotoxicity in mice.

Abstract Excitotoxicity is a process by which excitatory amino acids induce neuronal cell death. To what extent excitotoxicity is regulated by apoptotic molecules is currently unclear. We previously found that endonuclease G (EndoG) plays an important role in both normal apoptosis in vivo and in pre-implantation embryogenesis. To investigate whether EndoG participates in neuronal cell death, we compared EndoG expression and kainic acid (KA)-induced seizure behavior and excitotoxicity in EndoG +/− and wild-type mice. We found that EndoG expression in the hippocampus of EndoG +/− mice is reduced compared to that in the wild-type mice. The reduction of EndoG expression levels in the hippocampus did not result in altered KA-induced seizure severity in EndoG +/− mice compared to that in wild-type mice. However, both CA3 and CA1 pyramidal neurons in EndoG +/− mice are more resistant to KA-induced cell death than that in wild-type mice. These results indicate that reduced expression of EndoG in the hippocampi of EndoG +/− mice leads to resistance to excitotoxicity.
A motion phantom study on helical tomotherapy : the dosimetric impacts of delivery technique and motion

Helical tomotherapy (HT) can potentially be used for lung cancer treatment including stereotactic radiosurgery because of its advanced image guidance and its ability to deliver highly conformal dose distributions. However, previous theoretical and simulation studies reported that the effect of respiratory motion on statically planned tomotherapy treatments may cause substantial differences between the calculated and actual delivered radiation isodose distribution, particularly when the treatment is hypofractionated. In order to determine the dosimetric effects of motion upon actual HT treatment delivery, phantom film dosimetry measurements were performed under static and moving conditions using a clinical HT treatment unit. The motion phantom system was constructed using a programmable motor, a base, a moving platform and a life size lung heterogeneity phantom with wood inserts representing lung tissue with a 3.0 cm diameter spherical tumour density equivalent insert. In order to determine the effects of different motion and tomotherapy delivery parameters, treatment plans were created using jaw sizes of 1.04 cm and 2.47 cm, with incremental gantry rotation periods between the minimum allowed (10 s) and the maximum allowed (60 s). The couch speed varied from 0.009 cm s−1 to 0.049 cm s−1, and delivered to a phantom under static and dynamic conditions with peak-to-peak motion amplitudes of 1.2 cm and 2 cm and periods of 3 and 5 s to simulate human respiratory motion of lung tumours. A cylindrical clinical target volume (CTV) was contoured to tightly enclose the tumour insert. 2.0 Gy was prescribed to 95% of the CTV. Two-dimensional dose was measured by a Kodak EDR2 film. Dynamic phantom doses were then quantitatively compared to static phantom doses in terms of axial dose profiles, cumulative dose volume histograms (DVH), percentage of CTV receiving the prescription dose and the minimum dose received by 95% of the CTV. The larger motion amplitude resulted in more under-dosing at the ends of the CTV in the axis of motion, and this effect was greater for the smaller jaw size plans. Due to the size of the penumbra, the 2.47 cm jaw plans provide adequate coverage for smaller amplitudes of motion, ±0.6 cm in our experiment, without adding any additional margin in the axis of motion to the treatment volume. The periodic heterogeneous patterns described by previous studies were not observed from the single fraction of the phantom measurement. Besides the jaw sizes, CTV dose coverage is not significantly dependent on machine and phantom motion periods. The lack of adverse synchronization patterns from both results validate that HT is a safe technique for treating moving target and hypofractionation.
A neural network adaptive controller for a class of nonlinear systems

Abstract Adaptive control techniques can achieve impressive control results for systems which can be accurately modeled or estimated. This paper addresses the case of a nonlinear system for which no model exists, and for which the only available data are a set of inputs and measured state outputs. A back-propagation neural network is used to take the place of the system model in a standard adaptive control strategy. Computer simulation is presented which shows the success of this strategy for a discrete-time single-input, single-output (SISO) nonlinear system. Results can be extended to the multiple-input, multiple-output (MIMO) case.
STORAGE OF PHOSPHORUS IN NITROGEN‐FIXING ANABAENA FLOS‐AQUAE (CYANOPHYCEAE)1

P accumulation and metabolic pathway in N2-fixing Anabaena flos-aquae (Lyngb.) Breb were investigated in P-sufficient (20 μMP) and P-limited (2 μMP) turbidostats in combined N-free medium. The cyanobacterium grew at its maximum rate (μmax, 1.13 d−1) at the high P concentration and at 65% of μmax under P limitation, with total cell P concentrations (QP) at steady states of 12.0 and 5.2 fmol·cell−1, respectively. At steady state, polyphosphates (PPi) accounted for only 3% of QP (0.4 fmol·cell−1) in P-rich cells. Its concentration in P-limited cells was 5.8% (0.3 fmol·cell−1). On the other hand, sugar P was very high at 22% of QP in P-rich cells and was undetectable in P-limited cells. Pulse chase experiments with 32P showed that P-rich cells initially incorporated the labeled P into the acid-soluble PPi fraction within the first few minutes and to a lesser extent into nucleotide P. Radioactivity in the PPi then declined rapidly with concomitant increases in sugar P and nucleotide P fractions. In contrast, in P-limited cells, no radiolabel was detected in acid-soluble PPi, and 32P was initially incorporated into nucleotide P, sugar P, and ortho P fractions. The latter two fractions then subsequently declined. Therefore, under N2-fixing conditions the cyanobacteria appeared to store P as sugar P and also utilize P through different pathways under P-rich and -limited conditions. When nitrate was supplied as the N source under P-sufficient conditions, PPi accounted for about 15% of steady-state QP, but no sugar P was detected. Therefore, the same organism stored P in different cell P fractions depending on its N sources.
On the organ trail: insights into organ regeneration in the planarian

Advances in stem cell biology have led to the derivation of diverse cell types, yet challenges remain in creating complex tissues and functional organs. Unlike humans, some animals regenerate all missing tissues and organs successfully after dramatic injuries. Studies of organisms with exceptional regenerative capacity, like planarians, could complement in vitro studies and reveal mechanistic themes underlying regeneration on the scale of whole organs and tissues. In this review, we outline progress in understanding planarian organ regeneration, with focus on recent studies of the nervous, digestive, and excretory systems. We further examine molecular mechanisms underlying establishment of diverse cell fates from the planarian stem cell pool. Finally, we explore conceptual directions for future studies of organ regeneration in planarians.
NMR spectroscopy and free volume analysis of the effects of copolymer composition on the swelling kinetics and chain dynamics of highly crosslinked copolymers of acrylic acid with PEG-containing multiacrylates

Novel ionizable polymer networks were prepared from oligo(ethylene glycol) (OEG) multiacrylates and acrylic acid (AA), employing bulk radical photopolymerization techniques. The properties of these materials exhibited a complex dependence on the network structure and composition. Penetrant sorption experiments demonstrated that the crosslinked structure of the copolymers depended very strongly on the AA content as well as the number of ethylene glycol groups. The impact of varying the AA content and the oligo(ethylene glycol) chain length on the polymer chain dynamics was examined using diffusion and 13 C NMR relaxation studies. The penetrant uptake studies indicated a coupling of Fickian and relaxation-driven contributions to the swelling behavior. The effect of increasing the AA content on the characteristic chain relaxation time was reversed as the oligo(ethylene glycol) chain length was varied, indicating that chain relaxation is controlled by structural considerations, for shorter oligo(ethylene glycol) chains, and by compositional considerations, for longer oligo(ethylene glycol) chains. Measured compositional effects on solid state 13 C NMR relaxation times supported these conclusions.
'Crystal-like structures' of boiled beef heart mitochondria.

Abstract Electron micrographs of boiled beef heart mitochondria are presented. On heating the mitochondrial suspension for 7 min in a boiling water bath ‘crystal-like’ structures inside and inbetween the mitochondria became visible. It is suggested that these structures were formed by rearrangement of the mitochondrial structure.
Mate guarding as paternity insurance in Idaho ground squirrels.

FOLLOWING a copulation, males in many species of vertebrates (particularly birds)1–4 and invertebrates5,6 remain near the inseminated female and repel other suitors with displays or force. Guarding males must delay resumption of competitive mate searching7, but they may insure their paternity by reducing possibilities for secondary matings and sperm competition8,9. Among mammals, post-copulatory mate guarding has been reported in rodents10–12, mongooses13, ungulates14,15 and primates16,17, including humans18, but the effects of such behaviour on male reproductive success have not been determined genetically. I report here that mate guarding by male Idaho ground squirrels (Spermophilus brunneus) enhances a male's probability of paternity. Furthermore, an analysis based on game theory shows that mate guarding is an evolutionarily stable strategy for male S. brunneus, but not male Belding's ground squirrels (S. beldingi), which resume searching once copulation is completed.
Recognition and discrimination of emotional faces and pictures

Abstract In order to learn whether patients with right-hemisphere disease (RHD) had a deficit in their ability to discriminate and comprehend emotional faces and pictures, we studied nine patients with RHD, nine patients with left-hemisphere disease (LHD), and nine controls. The subjects were presented with six picture tests that comprised either emotional faces or emotional scenes. Their task was either to denote (name or choose) an emotion or to discriminate (same, different) between two faces or emotions. Patients with RHD performed significantly worse than subjects with LHD when asked to discriminate between faces, to discriminate between emotional faces, and to name emotional scenes. There was also a trend for the RHD group to be more impaired than the LHD group when asked to name the emotional face or choose the emotional face. Except for the facial and emotional discrimination tests, the LHD patients also performed worse than controls.
Supersaturated Island Faunas: A Species-Age Relationship for Lizards on Post-Pleistocene Land-Bridge Islands

Lizard faunas on post-Pleistocene land-bridge islands in the region of Baja California were examined for the effect of island age on species diversity. Species diversity and age are significantly correlated; and when the variation in species diversity attributable to area and latitude are removed, the corrected species diversity plotted against island age produces a relaxation or extinction curve. These results provide evidence for supersaturated faunas which are relaxing to lower levels of species diversity consistent with the equilibrium theory of island biogeography.
A survey of parallel computer architectures for the solution of the Navier-Strokes equations

Abstract This paper presents an overview of parallel computer architectures suitable for the solution of the Navier-Stokes partial differential equations. The equations and related numerical algorithms require vast amounts of computer resources, for which even today's supercomputers are inadequate. Both existing and proposed parallel computer architectures which are adaptable to this problem are discussed. Benchmarks for several specific examples are given.
In-situ formation of Cu metal crystals within nanostructured ZnO electrospun fibers

Abstract The in-situ synthesis of Cu/ZnO crystalline nanofibers is presented. The composite nanofibers are formed through the calcination and reduction of as-electrospun fibers consisting of poly(vinyl pyrrolidone) as well as Cu and ZnO precursors. The crystal structure and morphology of the synthesized fibers were characterized using X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. The presence of well crystallized Cu and ZnO phases within the fiber was verified using XRD spectra and HRTEM images. To the best of our knowledge, this analysis confirms the first successful in-situ synthesis of a metal nanocrystal and ceramic polycrystalline electrospun fiber hybrid.
THE SALE OF WHEAT TO THE USSR: A CHANGE IN US POLICY?

SUMMARY The desirability of United States trade with the USSR has been the subject of considerable debate for a number of years. The US government has generally restricted such trade, restraining its own citizens by fiat and trying to restrain the citizens of friendly nations through pressure on their respective governments. On October 9, 1963, President Kennedy announced that the US government would approve export licences for private grain traders seeking to sell wheat and other agricultural commodities to the Soviet bloc. The statement suggested a possible shift in US policy. Two major alternative hypotheses seem relevant in explaining the decision of the US to sell wheat to the USSR: (1) the gains accruing to the US relative to the gains accruing to the USSR are sufficiently more in favor of the US than previously available trade to justify the decision to trade, and (2) US policy is shifting toward a greater rapprochement with the USSR—that is, at the same relative gains from mutually beneficial trade, the US is willing to deny fewer gains to the USSR. One possible method of eveluating the two hypotheses would be to examine official statements in the US and abroad on this matter. However, the probability of error associated with believing the reasons individuals (or nations) offer to justify their behavior is exceptionally high. Accordingly, the hypotheses are evaluated by examining the data available, indicating the behavior implied by each hypothesis, and then examining the agreement of the implied with the observed behavior. The analysis suggests that the relative gains accruing to the US and to the USSR from the wheat transaction are such that the cost to the US of denying the concomitant gains to the USSR is higher than with respect to most other commodities. At the higher price, the US apparently has decided to buy less restriction of trade. Although the wheat sale may have been a trial balloon to test voters’ reaction to expanded trade with the USSR, the observational statements available to date are not inconsistent with the hypothesis that US policy has not changed.
CMOS active pixel sensor specific performance effects on star tracker/imager position accuracy

This paper gives the status of theoretical and experimental efforts at JPL in the development of environmentally robust (Radiation Hard and radiation Tolerant), ultra-low power, high performance CMOS active pixel sensor (APS) imagers for start tracker/imager applications. The work explores the effect of imager performance on star position accuracy, specifically examining the performance of JPL designed APS imagers. Accuracy is estimated as a function of star magnitude for a nominal star tracker optical design. Using these APS sensors, which have wide dynamic range and no blooming, simultaneous imaging of widely differing star magnitudes during the same observation is possible. It is shown that prototype Rad Hard APS imagers meet many next generation, star tracker/imager mission performance requirements when operated at reduced temperatures. These imagers also provide excellent performance at cryogenic operating temperatures appropriate to some anticipate flight missions. APS imagers with their high level of integration, on-chip timing and control, ultra-low power, and environmental robustness are excellent candidates for NASA's earth observing, interplanetary and deep space exploration missions.
Managing concomitant congenital diaphragmatic hernia, esophageal atresia, and tracheoesophageal fistula: A case report of a premature infant that achieved survival

Abstract Newborns with the constellation of congenital diaphragmatic hernia (CDH), esophageal atresia (EA), and tracheoesophageal fistula (TEF) present a unique clinical situation that requires well-coordinated multi-disciplinary management as it is most commonly fatal. The authors describe successful management of a premature infant diagnosed with left CDH, EA, and TEF in the United States, the first such case to be reported in this country.
First-Order Rate Equations in Geotechnical Engineering

First-order rate equations model physical or chemical processes in which the rate of approach to an end condition is proportional to the departure from that condition. Relationships were defined and tested with geotechnical problems including the prediction of end values for consolidation and for settlement from limited data. Solutions were obtained by substituting trial end values to obtain linearity of a prescribed relationship. The method does not require a thorough understanding of the mechanisms involved, but only that they be consistent and asymptotic to an end value. The mandatory linear relationship cannot be obtained if these criteria are not met, for example, for linear elastic behavior. First-order rate equations are discontinuous and overlap at behavioral boundaries such as that between primary and secondary consolidation. They also suggest a separate stage involving the loss of structure during consolidation of a quick clay. Settlement predictions are in close agreement with data from a grain...
Hydration behavior of heart muscle studies by nuclear magnetic relaxation: Deuterium exchange of water protons in the myocardium

Proton transverse relaxation, deuterium and oxygen-17 NMR measurements on functional animal heart muscle were employed to study the distribution and exchange of water protons in the heart. Our nonlinear regression analysis of such data showed the presence of three proton transverse relaxation components that are likely to correspond, respectively, to two major types of water compartments in the heart muscle and the heart muscle matrix. A deuterium exchange study was undertaken to obtain additional information concerning the chemical exchange of water protons/deuterium within these two water compartments, and the effects of proton intermolecular dipolar interactions on the transverse relaxation of water protons. Our results are likely to influence the analysis and interpretation of MRI data for myocardium since it provides details of the microscopic water distribution in the myocardium which is important to the heart function.
BIOSYNTHESIS OF LIVER PHOSPHOLIPIDS DURING THE DEVELOPMENT OF A FATTY LIVER.

Summary1. Liver total lipids, phospho-lipid P and phospholipid synthesis has been investigated during the development of a fatty-cirrhotic liver in animals maintained on a low-fat, low-protein diet for 17 to 297 days. 2. There is an increase in the specific and relative specific activities of total liver phospholipids between the 36th and 64th days, i.e., during the development of the fatty liver. 3. Chromatography of liver phospholipids and lipid phosphorylation during the development of a fatty liver was studied in rats maintained on low protein-low fat diets. 4. A statistically significant decrease of liver lecithin and sphingomyelin occurred at end of 5 weeks of dietary regime and continued to decrease as long as the animals were maintained on the low protein diet. 5. A statistically significant decrease of phosphatidyl ethanolamine and phosphatidyl inositol occurs at the end of 9 weeks on the dietary regime. 6. A reduction of dietary protein intake for 4 weeks results in a statistically significant d...
Preclinical pharmacology of the anthrapyrazole analog oxantrazole (NSC-349174, Piroxantrone)

Oxantrazole (now designated as piroxantrone) is an anthrapyrazole analog under evaluation as a potentially useful anthracycline-like antitumor agent. In preparation for phase I clinical trials, we characterized certain aspects of oxantrazole preclinical pharmacology, including plasma stability, murine pharmacokinetics, in vitro/in vivo metabolism, and DNA damage following incubation with human tumor cells in culture. Oxantrazole was relatively unstable in fresh mouse and dog plasma and particularly unstable in fresh human plasma (t1/2 >5 min at 37°C). Its decomposition in plasma was prevented by the addition of ascorbic acid, suggesting oxidative degradation. following rapid i.v. administration of oxantrazole to mice, plasma elimination was best described by a two-compartment open model with an elimination-phase half-life, total body clearance, and steady-state volume of distribution of 330 min, 458 ml/min per m2, and 87.9 l/m2, respectively. The c x t value calculated following i.v. administration of 90 mg/m2 oxantrazole to mice was 177 μg-min/ml. This value was subsequently used in a pharmacologically guided dose-escalation scheme for the oxantrazole phase I clinical trial. Oxantrazole was converted to a polar conjugate, presumably a β-glucuronide, by rat but not mouse hepatic microsomal preparations and in vivo by the mouse. Oxantrazole introduced protein-associated DNA strand breaks following incubation with a human rhabdomyosarcoma cell line. Repair of the damage was complete by 15 h. Clinical pharmacologic studies are currently under way in conjunction with the phase I clinical trial of oxantrazole.
Longest Edge Routing on the Spatial Aloha Graph

The multihop spatial reuse Aloha (MSR-Aloha) protocol was recently introduced by Baccelli et aL, where each transmitter selects the receiver among its feasible next hops that maximizes the forward progress of the head of line packet towards its final destination. They identify the optimal medium access probability (MAP) that maximizes the spatial density of progress, defined as the product of the spatial intensity of attempted transmissions times the average per-hop progress of each packet towards its destination. We propose a variant called longest edge routing where each transmitter selects its longest feasible edge, and then identifies a packet in its backlog whose next hop is the associated receiver. The main contribution of this work (and of Baccelli et aL) is the use of stochastic geometry to identify the optimal MAP and the corresponding optimal spatial density of progress.
Hippocampal neuron soma size is associated with population differences in winter climate severity in food‐caching chickadees

Summary 1. Differential demands on cognitive ability may be expected to result in the evolution of cognition and associated changes in underlying neural mechanisms. While most comparative studies of cognition have focused on volumetric brain measurements, it remains unclear whether neuron morphology, which appears to be directly linked to cognitive functions, may be responsive to differential selection on cognitive ability. 2. Food-caching birds rely on caches to survive winter and use spatial memory to recover previously stored food. Birds in more harsh winter climates have been hypothesized to be more dependent on cached food, and therefore, their winter survival may be expected to be more memory-dependent relative to their conspecifics from the milder winter climates. Here, we show that neuron soma size in the hippocampus, a brain region involved in memory function, exhibits significant population variation associated with different environmental pressures on spatial memory related to differences in winter climate harshness in two species of foodcaching chickadees. Comparing ten populations of black-capped chickadees and three populations of mountain chickadees along a gradient of winter climate harshness, we found that birds from harsher environments had significantly larger hippocampal neuron soma sizes. 3. Using chickadees from the two most divergent populations reared in a laboratory environment, we showed that these differences appear to be at least partly heritable as significant differences between these populations remained in birds sharing the same laboratory environment. At the same time, laboratory-reared birds had significantly smaller neuron soma size compared with the wild-sampled birds, suggesting that at least some variation in neuron soma size may be due to environment-related plasticity. 4. Our data suggest that environment-related selection on memory may generate differences in neuron morphology, which appear to be controlled by some heritable mechanisms and likely underlie population differences in spatial memory.
Sexual Acceptability of Laboratory Strains of Male House Flies in Competition with Wild Strains

The insemination rate of 3 laboratory strains of house flies, Musca domestica L., was compared by mating the males of all 3 strains with females of 1 strain. Also the success of 2 laboratory strains of male house flies, normal and treated with a chemosterilant, in competition for females with males from a wild strain was compared. The females of all strains mated more readily with the males of their own strain, whether or not, the males were sterilized. Chemosterilized males competed more successfully than normal males of the same strain when they were mated with females of that strain.
Papillary tissue fragments as a diagnostic pitfall in fine-needle aspirations of thyroid nodules

Fine-needle aspirates of three thyroid nodules displayed hypercellularity and papillary tissue fragments that suggested neoplasms. Neither microfollicles (either empty or with inspissated colloid) nor the characteristic nuclei of papillary carcinoma were evident. Surgical specimens contained adenomatoid nodules with focal papillary hyperplasia. These cases demonstrate that no single cytologic feature should be used independently in the cytologic diagnosis of thyroid lesions. Tumor cellularity and papillary tissue fragments should not be equated with neoplasia per se; all cytomorphologic features should be evaluated.
Molecular characterization of a novel defect occurring de novo associated with erythropoietic protoporphyria

Abstract A ferrochelatase (FC) mRNA lacking exon 4 was detected in a patient with erythropoietic protoporphyria (EPP). The mutation responsible for the exon skipping was a novel one: a G → C transition at the − 1 position of the exon 4 donor site (nucleotide 463). The efficiency of missplicing was not 100%. The same mutation could alternatively result in exon 4 skipping or act as a missense mutation (G463 → C, predicting an Ala155 → Pro substitution), that inactivates the FC activity almost completely. Both parents were negative for the mutation and DNA fingerprinting indicated that both of them are the biological parents with 99.58% certainty. This is the first report of a de novo mutation in EPP.
Acoustic similarity effects on retrieval from secondary memory

Secondary memory (SM) was tested by a delayed free-recall procedure. Experimental lists contained sets of four critical words, either acoustically or semantically related, which were either massed in early input positions, massed in late input positions, or distributed throughout a sequence of words. In control lists, critical serial positions were occupied by items which were neither semantically nor acoustically related. Recall of semantically similar words substantially exceeded that of critical control words regardless of how they were presented. By contrast, significant acoustic similarity effects were obtained only when critical words were massed early or late and not when they were distributed throughout a list. Temporal overlap during list presentation of the acoustically related traces in primary memory appears to be a sufficient condition for acoustic information to play an important role during retrieval from SM.
Models of gas-grain chemistry in interstellar cloud cores with a stochastic approach to surface chemistry

We present a gas-grain model of homogeneous cold cloud cores with time-independent physical conditions. In the model, the gas-phase chemistry is treated via rate equations while the diffusive granular chemistry is treated stochastically. The two phases are coupled through accretion and evaporation. A small network of surface reactions accounts for the surface production of the stable molecules water, formaldehyde, methanol, carbon dioxide, ammonia, and methane. The calculations are run for a time of 10 7 years at three different temperatures: 10 K, 15 K, and 20 K. The results are compared with those produced in a totally deterministic gas-grain model that utilizes the rate equation method for both the gas-phase and surface chemistry. The results of the different models are in agreement for the abundances of the gaseous species except for later times when the surface chemistry begins to affect the gas. The agreement for the surface species, however, is somewhat mixed. The average abundances of highly reactive surface species can be orders of magnitude larger in the stochastic-deterministic model than in the purely deterministic one. For non-reactive species, the results of the models can disagree strongly at early times, but agree to well within an order of magnitude at later times for most molecules. Strong exceptions occur for CO and H2CO at 10 K, and for CO2 at 20 K. The agreement seems to be best at a temperature of 15 K. As opposed to the use of the normal rate equation method of surface chemistry, the modified rate method is in significantly better agreement with the stochastic-deterministic approach. Comparison with observations of molecular ices in dense clouds shows mixed agreement.
No effect of bicarbonate treatment on insulin sensitivity and glucose control in non-diabetic older adults.

Chronic mild metabolic acidosis is common among older adults, and limited evidence suggests that it may contribute to insulin resistance and type-2 diabetes. This analysis was conducted to determine whether bicarbonate supplementation, an alkalinizing treatment, improves insulin sensitivity or glucose control in non-diabetic older adults. Fasting blood glucose and insulin were measured in stored samples from subjects who had completed a 3-month clinical trial of bicarbonate supplementation to improve indicators of bone and muscle health. One hundred and fifty three ambulatory, non-diabetic adults aged 50 years and older were studied. Subjects were randomized to one of two bicarbonate groups (67.5 mmol/day of potassium bicarbonate or sodium bicarbonate) or to one of two no-bicarbonate groups (67.5 mmol/day of placebo or potassium chloride). Subjects remained on treatment throughout the 3-month study. The primary outcome measures were changes in fasting plasma glucose, serum insulin and HOMA-IR, an index of insulin resistance. Bicarbonate supplementation reduced net acid excretion (adjusted mean ± SEM for the change in NAE/creatinine, mmol/mmol, was 0.23 ± 0.22 in the no-bicarbonate group compared with −3.53 ± 0.22 in the bicarbonate group, P < 0.001) but had no effect on fasting plasma glucose, serum insulin, or HOMA-IR. In conclusion, bicarbonate supplementation does not appear to improve insulin sensitivity or glucose control in non-diabetic older adults.
Telomeres and telomerase: more than the end of the line.

Early studies of telomerase suggested that telomeres are maintained by an elegant but relatively simple and highly conserved mechanism of telomerase-mediated replication. As we learn more, it has become clear that the mechanism is elegant but not as simple as first thought. It is also evident that, although many species use similar, sometimes identical, DNA sequences for telomeres, these species express their own individuality in the way they regulate these sequences and, perhaps, in the additional tasks that they have imposed on their telomeric DNA. The striking similarities between telomeres in different species have revealed much about chromosome ends; the differences are proving to be equally informative. In addition to the differences between species that use telomerase, there are also a few exceptional organisms with atypical telomeres for which no telomerase activity has been detected. This review addresses recent studies, the insights they offer, and, perhaps more importantly, the questions they raise.
Braconid parasitoids of Tephritidae (Diptera) infesting coffee and other fruits in West-Central Africa.

Exploration for parasitoids ofCeratitis capitata (Wiedemann) [Diptera: Tephritidae] was conducted in Cameroon and Togo and parasitoids collected were released in Costa Rica. Collections yielded large numbers ofOpius perproximus Silvestri,Biosteres caudatus Szepligeti, andB. caudatus auct. [Opiinae: Braconidae]. Other Opiines collected wereB. fullawayi (Silvestri),B. desideratus (Bridwell), and an undescribed species ofOpius. Parasitization of tephritids in coffee ranged from 10–56%, with an average 35% parasitism in a research plantation and 17% in a commercial plantation. Parasitism in fruits other than coffee was less than 5%. The most commonly reared tephritids from coffee wereTrirhithrum coffeae Bezzi andC. (Pterandrus) anonae Graham.C. capitata occurred in low frequency in coffee; and adults were rarely observed. Other rearings includedT. albonigrum (Enderlein),T. sp. nr.validum Bezzi,T. nigerrimum auct. nec. Bezzi,C. (Pterandrus) colae Silvestri,C. (Pterandrus) flexuosa (Walker),C. (Ceratalaspis) spp.cosyra (Walker) group,C. (Pardalaspis) sp.punctata (Wiedemann) group,C. (Ceratalaspis) giffardi Bezzi,Dacus (Dacus) bivittatus (Bigot),D. (Didacus) ciliatus Loew, andGymnodacus sp.
Systematic instruction in simple programming gambits

This paper describes an approach to teaching programming that the writer follows in his sections of the main introductory PL/I programming course at Brooklyn College, in a forthcoming text - An Introduction to PL/I Programming, and in material being prepared for use in the local public schools. The subject is developed by reference to carefully paced examples of programs that use different programming “gambits”, in isolation and in combination. The programs all relate to plausible applications. The gambits have been systematized, and an order of presentation established that matches the developing needs of professionals in other disciplines, whose potential use of computers is dominated by information processing rather than numerical computation.
RIGHT-LEFT DIFFERENCES IN TACHISTOSCOPIC IDENTIFICATION OF PARALOGS AS A FUNCTION OF ORDER OF APPROXIMATION TO ENGLISH LETTER SEQUENCES.

Words and paralogs varying in order of approximation to English letter sequences were presented for tachistoscopic identification randomly in the right and left visual fields. The data showed significant right-left differences for words and for 2nd and 4th order approximations to English letter sequences. The results are interpreted as supporting a view of right-left retinal differences in tachistoscopic identification as related to congruence with previously established reading habits.
An Implicit-Explicit Hybrid Solver for a System of Stiff Kinetic Equations

A new stiff ordinary differential equation solver has been devised that separates the unknown variables into a fast group and a slow group. The fast variables are solved using the implicit backward-differentiation formulas but with a Jacobian of much smaller dimension than that of the original stiff system. The slow variables are solved using a simple explicit Adams-Bashforth scheme. The method, applied to a stiff atmospheric chemical system, yields an accuracy in the solution comparable to that of the commonly-used LSODE method at a relative tolerance level of 10-3 and an absolute tolerance level of 10-7 ppm, with one-third the execution time of LSODE. The method can be further fine-tuned to optimize its accuracy and execution time. As it is, the method should be an excellent candidate for the chemistry solver in air quality, combustion, and reactive flow models.
Current Concepts in the Evaluation and Treatment of the Shoulder in Overhead-Throwing Athletes, Part 1: Physical Characteristics and Clinical Examination

The overhead-throwing athlete is a challenging sports medicine patient. The repetitive microtraumatic stresses imposed on the athlete’s shoulder joint complex during the throwing motion constantly places the athlete at risk for injury. These stresses may effect several adaptations to normal shoulder range of motion, strength, and scapula position. The clinician should therefore appreciate the unique physical characteristics of the overhead-throwing athlete to accurately evaluate and treat throwing-related injuries.
SU‐E‐T‐859: A New Approach to Improve IMRT Delivery Efficiency by Intensity Map Discretization

Purpose: To minimize IMRT treatment monitor units and delivery time without compromising dosimetric quality in an in‐house treatment planning system. Methods: In‐house treatment planning system PLanUNC employs a two‐step process to generate a MLC‐IMRT treatment plan. First, the index‐dose gradient minimization dose optimization process produces a continuous intensity map. Second, MLC segmentation process converts the intensity map into MLC segments. This two‐step process is sensitive to MLC segmentation technique and can lead to excessive number of segments and dosimetric degradation. We developed a new method that discretizes the intensity map during optimization. The new method considered each beam in turn: its intensity map was optimized using the current dose distribution; the optimized intensity map was discretized according to its statistical distribution; the dose distribution was updated after discretization. In this process, the peaks and valleys in the continuous intensity map were converted into discrete plateaus, and the optimization of remaining beams mitigated possible degradation of dose conformity introduced by the discretization of previous beams. MLC segmentation was applied to the discretized fluence maps. This new approach is being validated using prostate and head and neck cases. Results: For the prostate, with no compromise to dose conformity, the number of segments was reduced by 40%, and the MUs reduced by ∼10%. For the head and neck, the number of segments was reduced by 20%, and a small dose escalation was observed in adjacent normal tissues; this may be due to complex constraints used in the optimization process and could be accommodated by re‐optimizing the beam weight using fixed beam apertures in the future. Conclusions: Discretization based on statistical distribution of beamlet intensity could effectively reduce IMRT beam complexity and result in shorter treatment time.