cssi/SciSciGPT-SciSciNet huggingface dataset:
Calculations of solar shortwave heating rates due to black carbon and ozone absorption using in situ measurements

Results for the solar heating rates in ambient air due to absorption by black-carbon (BC) containing particles and ozone are presented as calculated from airborne observations made in the tropical tropopause layer (TTL) in January-February 2006. The method uses airborne in situ observations of BC particles, ozone and actinic flux. Total BC mass is obtained along the flight track by summing the masses of individually detected BC particles in the range 90 to 600-nm volume-equivalent diameter, which includes most of the BC mass. Ozone mixing ratios and upwelling and partial downwelling solar actinic fluxes were measured concurrently with BC mass. Two estimates used for the BC wavelength-dependent absorption cross section yielded similar heating rates. For mean altitudes of 16.5, 17.5, and 18.5 km (0.5 km) in the tropics, average BC heating rates were near 0.0002 K/d. Observed BC coatings on individual particles approximately double derived BC heating rates. Ozone heating rates exceeded BC heating rates by approximately a factor of 100 on average and at least a factor of 4, suggesting that BC heating rates in this region are negligible in comparison.
Activation of rat liver cholesterol ester hydrolase by cAMP-dependent protein kinase and protein kinase C.

Short term regulation of hepatic cholesterol ester hydrolase by reversible phosphorylation is described. Two different kinase systems seem to be involved in this regulation. The addition of ATP, cyclic AMP and Mg2+ to rat liver 104,000× g supernatant (S104) produced a 100–140% increase in cholesterol ester hydrolase activity. This stimulation was abolished when protein kinase inhibitor was added prior to the addition of ATP, cyclic AMP and Mg2+. Cholesterol ester hydrolase activity was also stimulated when calcium ions, phosphatidylserine, and diolein were added to S104 along with ATP and Mg2+. Diolein in this reaction could be substituted by phorbol 12-myristate 13-acetate. Preincubation of S104 with alkaline phosphatase resulted in a deactivation of cholesterol ester hydrolase. The addition of increasing concentrations of Mg2+ to S104 produced increasing inhibition of cholesterol ester hydrolase activity, and this effect was blocked by NaF.
In vitro activity of an oral iminomethoxy aminothiazolyl cephalosporin, R-3746

The in vitro activity of R-3746, an iminomethoxy aminothiazolyl cephalosporin with a CH2OCH3 moiety at position 3, was compared with those of other antibiotics. R-3746 inhibited the majority of hemolytic streptococci (groups A, B, C, F, and G) and Streptococcus pneumoniae at less than 0.06 micrograms/ml, which was comparable to the activity of amoxicillin, 2- to 8-fold more active than cefixime, and 16- to 64-fold more active than cefaclor and cephalexin. Ninety percent of beta-lactamase-producing Haemophilus influenzae and Neisseria gonorrhoeae were inhibited at a concentration 0.25 micrograms/ml, but it was less active against Branhamella spp. It did not inhibit (MIC, greater than 16 micrograms/ml) enterococci, viridans group streptococci, or methicillin-resistant staphylococci. The MICs of R-3746 for 90% of strains tested for Escherichia coli; Klebsiella pneumoniae; Citrobacter diversus; Proteus mirabilis; and Salmonella, Shigella, and Yersinia spp. were less than or equal to 1 micrograms/ml. It was two- to eightfold less active than cefixime but was markedly superior to cefaclor, cephalexin, amoxicillin-clavulanate, and trimethoprimsulfamethoxazole. R-3746 inhibited 50% of Enterobacter cloacae, Enterobacter aerogenes, Citrobacter freundii, Morganella spp., Providencia spp., Proteus vulgaris, and Serratia marcescens at less than or equal to 8 micrograms/ml. Pseudomonas spp. were resistant. Fifty percent of Clostridium spp. were inhibited by 0.5 micrograms/ml, but MICs for Bacteroides spp. were greater than 128 micrograms/ml. R-3746 was not appreciably hydrolyzed by most chromosomal and plasmid-mediated beta-lactamases.
Effect of nonproximate atomic substitution on excited state intramolecular proton transfer

The central C atom of the OCCCO skeleton of the malonaldehyde molecule is replaced by N, and the effects upon the intramolecular H-bond and the proton transfer are monitored by ab initio calculations in the ground and excited electronic states. The H-bond is weakened in the singlet and triplet states arising from nπ* excitation in both molecules, which is accompanied by a heightened barrier to proton transfer.3ππ* behaves in the same manner, but the singlet ππ* state has a stronger H-bond and lower barrier. Replacement of the central C atom by N strengthens the intramolecular H-bond. Although the proton transfer barrier in the ground state of formimidol is lower than in malonaldehyde, the barriers in all four excited states are higher in the N-analog. The latter substitution also dampens the effect of the nπ* excitation upon the H-bond and increases the excitation energies of the various states, particularly ππ*. © 1998 John Wiley & Sons, Inc. J Comput Chem 19: 129–138, 1998
Integrating ns-3 model construction, description, preprocessing, execution, and visualization

There are many examples of meta-languages to describe computer network models, experiment designs, data formats, and visualization parameters. It is clear that the field recognizes the importance and benefits of a concise, portable and precise problem description, abstracted from the native representation used by any specific modeling or visualization framework. Yet none of the prior efforts have achieved widespread adoption. In this paper we discuss some of the issues in developing a model abstraction of wide utility. We survey the various communities that would benefit from such an abstraction, a range of use cases, and some of the semantic difficulties encountered. We propose a path forward to address the needs of various parts of the ns3 ecosystem, in a way that can be generalized to other network simulation frameworks and communities.
Plasma osmotic, Na+ and Cl− regulation under euryhaline conditions in Cyprinodon variegatus lacépède

Abstract 1. 1. Plasma osmotic, Na + and Cl − concentrations were evaluated in the teleost fish Cyprinodon variegatus Lacepede following acclimation in a series of ambient salinities from 1% sea-water (SW) to 360% SW. 2. 2. Plasma osmotic concentrations ranged from 337 ± 13 to 635 ± 39 mOsm/kg while plasma Na + ranged from 165 ± 8 to 285 ± 19 meq/l, and plasma Cl − from 129 ± 12 to 270 ± 19 meq/1 over this ambient range. 3. 3. Plasma Na + was more tightly regulated than plasma Cl − , with a Na + : Cl − ratio of 1.28 in 1% SW and 1.05 in 360% SW. 4. 4. Contributions of Na + plus Cl − to total osmotic concentration were not significantly altered over the ambient range.
Pancreatic cancer epidermal growth factor receptor (EGFR) intron 1 polymorphism influences postoperative patient survival and in vitro erlotinib response.

Background Epidermal growth factor receptor (EGFR) has a highly polymorphic CA repeat region that affects transcription efficiency and anti-EGFR drug sensitivity in carcinomas. Erlotinib is an EGFR tyrosine kinase inhibitor approved for pancreatic cancer treatment. We analyzed the impact of EGFR intron 1 CA repeat lengths in pancreatic cancer clinical outcome and in vitro response to erlotinib.
δ‐opioid receptor is present in presynaptic axon terminals in the rat nucleus locus coeruleus: Relationships with methionine5‐enkephalin

The three classes of opioid receptors, mu, delta, and kappa, are distributed within the locus coeruleus (LC) of the rat brain. We have recently shown with immunoelectron microscopy that the mu-opioid receptor (muOR) is localized prominently to extrasynaptic sites on the plasma membranes of noradrenergic perikarya and dendrites of the LC. To further characterize the cellular distribution of other opioid receptors in this region, in this study, we examined the ultrastructural localization of an antipeptide sequence unique to the delta-opioid receptor (deltaOR) in sections that were also dual labeled for methionine-enkephalin (M-ENK), an opioid peptide known to be an endogenous ligand of the deltaOR. Immunoperoxidase labeling for deltaOR was localized primarily to the plasma membranes of presynaptic axon terminals and was also associated with large dense core vesicles. The deltaOR-labeled axon terminals formed both excitatory (asymmetric) and inhibitory (symmetric) type synaptic specializations with unlabeled dendrites and were frequently apposed by astrocytic processes. Dual labeling showed that, of 180 deltaOR-labeled axon terminals, 16% showed colocalization with M-ENK. These formed both types of synaptic junctions. Peroxidase labeling for deltaOR was also observed occasionally within dendrites, unmyelinated axons, and glial processes. The deltaOR-labeled dendrites were usually postsynaptic to unlabeled axon terminals that contained both small clear and large dense core vesicles. These results provide the first ultrastrucutral evidence that, in the LC, deltaOR may play a role in the presynaptic modulation of release of both excitatory and inhibitory neurotransmitters. They also suggest involvement of deltaOR in autoregulation of M-ENK release from axon terminals in this region.
Dysgranulopoiesis is an independent adverse prognostic factor in chronic myeloid disorders with an isolated interstitial deletion of chromosome 5q

Dysgranulopoiesis is an independent adverse prognostic factor in chronic myeloid disorders with an isolated interstitial deletion of chromosome 5q
D/H isotope ratios of kerogen, bitumen, oil, and water in hydrous pyrolysis of source rocks containing kerogen types I, II, IIS, and III

Abstract Immature source rock chips containing different types of kerogen (I, II, IIS, III) were artificially matured in isotopically distinct waters by hydrous pyrolysis and by pyrolysis in supercritical water. Converging isotopic trends of inorganic (water) and organic (kerogen, bitumen, oil) hydrogen with increasing time and temperature document that water-derived hydrogen is added to or exchanged with organic hydrogen, or both, during chemical reactions that take place during thermal maturation. Isotopic mass-balance calculations show that, depending on temperature (310–381°C), time (12–144 h), and source rock type, between ca. 45 and 79% of carbon-bound hydrogen in kerogen is derived from water. Estimates for bitumen and oil range slightly lower, with oil–hydrogen being least affected by water-derived hydrogen. Comparative hydrous pyrolyses of immature source rocks at 330°C for 72 h show that hydrogen in kerogen, bitumen, and expelled oil/wax ranks from most to least isotopically influenced by water-derived hydrogen in the order IIS > II ≈ III > I. Pyrolysis of source rock containing type II kerogen in supercritical water at 381°C for 12 h yields isotopic results that are similar to those from hydrous pyrolysis at 350°C for 72 h, or 330°C for 144 h. Bulk hydrogen in kerogen contains several percent of isotopically labile hydrogen that exchanges fast and reversibly with hydrogen in water vapor at 115°C. The isotopic equilibration of labile hydrogen in kerogen with isotopic standard water vapors significantly reduces the analytical uncertainty of D/H ratios when compared with simple D/H determination of bulk hydrogen in kerogen. If extrapolation of our results from hydrous pyrolysis is permitted to natural thermal maturation at lower temperatures, we suggest that organic D/H ratios of fossil fuels in contact with formation waters are typically altered during chemical reactions, but that D/H ratios of generated hydrocarbons are subsequently little or not affected by exchange with water hydrogen at typical reservoir conditions over geologic time. It will be difficult to utilize D/H ratios of thermally mature bulk or fractions of organic matter to quantitatively reconstruct isotopic aspects of paleoclimate and paleoenvironment. Hope resides in compound-specific D/H ratios of thermally stable, extractable biomarkers (“molecular fossils”) that are less susceptible to hydrogen exchange with water-derived hydrogen.
Nutritional Selenium Supplements: Product Types, Quality, and Safety

Selenium supplements contain selenium in different chemical forms. In the majority of supplements, the selenium is present as selenomethionine. However, in multivitamin preparations, infant formulas, protein mixes, weight-loss products and animal feed, sodium selenite and sodium selenate are predominantly used. In some products, selenium is present in protein- or amino acid chelated forms; in still others, the form of selenium is not disclosed. Current evidence favors selenomethionine over the other forms of selenium. Extradietary supplementation of selenium at the dosage of 200 micrograms per day is generally considered safe and adequate for an adult of average weight subsisting on the typical American diet.
The nerve sheath tumor, solitary and in von Recklinghausen's disease; A unitary mesenchymal concept

The characteristic cell of peripheral nerves, the Schwann cell, is capable of forming peripheral myelin, but also of forming collagen and reticulin fibers and of being transformed into macrophages. This kind of cell has been demonstrated under circumstances in which its formation from pre-existing Schwann cells is precluded, as in regenerative foci within the brain in multiple sclerosis. It is suggested that this cell is a specilized mesenchymal element, and that it may be formed by maturation of the multipotential primitive reticular cells which give rise to other specialized mesenchymal elements in appropriate circumstances, and which are present in the brain as well as in most other tissues. It is suggested that only one type of neoplasm of specific Schwann cell origin exists, this being the same in the presence or absence of von Recklingshausen's neurofibromatosis. It may most simply be designated as the nerve sheath tumor. Von Recklinghausen's disease, however, is characterized by the occurrence of hamartomatous and degenerative phenomena, as well as the tendency to neoplasia, and these alter the appearnce of the specific nerve sheath tumor and of non-neoplastic segments of peripheral nerves. In addition, some neoplasms observed in this disease have been interpreted as of Schwann cell origin when, in fact, they are less specific fibromas originating in other connective tissue elements of a nerve, or in the extra-neural connective tissues. The term “neurofibroma” appears to have been applied to both of these phenomena, i.e., to degenerative, non-neoplastic changes in nerves, and to neoplasms which may not have originated in Schwann cells or even within peripheral nerves; its continued use is not warranted.
Growth, Yield, and Yield Component Changes among Old and New Soybean Cultivars

Soybean [Glycine max (L.) Merr.] yield has increased at a rate of 25 to 30 kg ha -1 yr -1 due in part to improved genetic gain, and has been further advanced by the addition of resistance to soybean cyst nematode (Heterodera glycines Ichinohe; SCN) in new cultivars. The objective was to determine specific growth changes that explain the yield improvement from old to new cultivars and the further yield improvement gained from the addition of SCN resistance. Studies were conducted at three Iowa locations during 2005 and 2006. Two old and two new SCN-susceptible, and two new SCN-resistant cultivars were evaluated for total dry matter (TDM) accumulation and leaf area index (LAI) through the season along with yield and yield components at harvest. New cultivars produced yields superior to older cultivars due to increased crop growth rate (CGR) culminating in greater TDM 105 days after emergence (DAE). Yield was strongly associated with the number of seeds produced m -2 and this yield component accounted for almost all of the yield differences among cultivars. Seeds m -2 was positively related to CGR between 42 and 105 (growth stage R1-R5.5) DAE and to LAI 105 DAE. New SCN-resistant cultivars produced yields 17 to 19% greater than new susceptible cultivars across three locations. Increased TDM and CGR explained the yield response at the low-yield location, but not at the high-yield locations. Apparent harvest index (HI) was similar among all cultivars at each location. Selection for increased yield has indirectly selected for increased TDM and CGR with a similar amount partitioned to seed dry weight. Future yield gains will be made by (i) increasing the amount and the rate of dry matter (DM) and (ii) through the increased production and duration of leaf area.
Inorganic arsenic compounds cause oxidative damage to DNA and protein by inducing ROS and RNS generation in human keratinocytes.

Arsenic is a naturally occurring element that is present in food, soil, and water. Inorganic arsenic can accumulate in human skin and is associated with increased risk of skin cancer. Oxidative stress due to arsenic exposure is proposed as one potential mode of carcinogenic action. The purpose of this study is to investigate the specific reactive oxygen and nitrogen species that are responsible for the arsenic-induced oxidative damage to DNA and protein. Our results demonstrated that exposure of human keratinocytes to trivalent arsenite caused the generation of 8-hydroxyl-2′-deoxyguanine (8-OHdG) and 3-nitrotyrosine (3-NT) in a concentration- and time-dependent manner. Pentavalent arsenate had similar effects, but to a significantly less extent. The observed oxidative damage can be suppressed by pre-treating cells with specific antioxidants. Furthermore, we found that pre-treating cells with Nω-nitro-l-arginine methyl ester (l-NAME), an inhibitor of nitric oxide synthase (NOS), or with 5,10,15,20-tetrakis (N-methyl-4′-pyridyl) porphinato iron (III) chloride (FeTMPyP), a decomposition catalyst of peroxynitrite, suppressed the generation of both 8-OHdG and 3-NT, which indicated that peroxynitrite, a product of the reaction of nitric oxide and superoxide, played an important role in arsenic-induced oxidative damage to both DNA and protein. These findings highlight the involvement of peroxynitrite in the molecular mechanism underlying arsenic-induced human skin carcinogenesis.
Vacuum-annealed Cu contacts for graphene electronics

Abstract We present transfer length method measurements of the contact resistance between Cu and graphene, and a method to significantly reduce the contact resistance by vacuum annealing. Even in samples with heavily contaminated contacts, the contacts display very low contact resistance post annealing. Due to the common use of Cu, and its low chemical reactivity with graphene, thermal annealing will be important for future graphene devices requiring non-perturbing contacts with low contact resistance.
Rising cyclin-CDK levels order cell cycle events.

Background Diverse mitotic events can be triggered in the correct order and time by a single cyclin-CDK. A single regulator could confer order and timing on multiple events if later events require higher cyclin-CDK than earlier events, so that gradually rising cyclin-CDK levels can sequentially trigger responsive events: the “quantitative model” of ordering. Methodology/Principal Findings This ‘quantitative model’ makes predictions for the effect of locking cyclin at fixed levels for a protracted period: at low cyclin levels, early events should occur rapidly, while late events should be slow, defective, or highly variable (depending on threshold mechanism). We titrated the budding yeast mitotic cyclin Clb2 within its endogenous expression range to a stable, fixed level and measured time to occurrence of three mitotic events: growth depolarization, spindle formation, and spindle elongation, as a function of fixed Clb2 level. These events require increasingly more Clb2 according to their normal order of occurrence. Events occur efficiently and with low variability at fixed Clb2 levels similar to those observed when the events normally occur. A second prediction of the model is that increasing the rate of cyclin accumulation should globally advance timing of all events. Moderate (<2-fold) overexpression of Clb2 accelerates all events of mitosis, resulting in consistently rapid sequential cell cycles. However, this moderate overexpression also causes a significant frequency of premature mitoses leading to inviability, suggesting that Clb2 expression level is optimized to balance the fitness costs of variability and catastrophe. Conclusions/Significance We conclude that mitotic events are regulated by discrete cyclin-CDK thresholds. These thresholds are sequentially triggered as cyclin increases, yielding reliable order and timing. In many biological processes a graded input must be translated into discrete outputs. In such systems, expression of the central regulator is likely to be tuned to an optimum level, as we observe here for Clb2.
Neph1 regulates steady-state surface expression of Slo1 Ca2+-activated K+ channels: different effects in embryonic neurons and podocytes

Large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels encoded by the Slo1 gene are often components of large multiprotein complexes in excitable and nonexcitable cells. Here we show that Slo1 proteins interact with Neph1, a member of the immunoglobulin superfamily expressed in slit diaphragm domains of podocytes and in vertebrate and invertebrate nervous systems. This interaction was established by reciprocal coimmunoprecipitation of endogenous proteins from differentiated cells of a podocyte cell line, from parasympathetic neurons of the embryonic chick ciliary ganglion, and from HEK293T cells heterologously expressing both proteins. Neph1 can interact with all three extreme COOH-terminal variants of Slo1 (Slo1(VEDEC), Slo1(QEERL), and Slo1(EMVYR)) as ascertained by glutathione S-transferase (GST) pull-down assays and by coimmunoprecipitation. Neph1 is partially colocalized in intracellular compartments with endogenous Slo1 in podocytes and ciliary ganglion neurons. Coexpression in HEK293T cells of Neph1 with any of the Slo1 extreme COOH-terminal splice variants suppresses their steady-state expression on the cell surface, as assessed by cell surface biotinylation assays, confocal microscopy, and whole cell recordings. Consistent with this, small interfering RNA (siRNA) knockdown of endogenous Neph1 in embryonic day 10 ciliary ganglion neurons causes an increase in steady-state surface expression of Slo1 and an increase in whole cell Ca(2+)-dependent K(+) current. Surprisingly, a comparable Neph1 knockdown in podocytes causes a decrease in surface expression of Slo1 and a decrease in whole cell BK(Ca) currents. In podocytes, Neph1 siRNA also caused a decrease in nephrin, even though the Neph1 siRNA had no sequence homology with nephrin. However, we could not detect nephrin in ciliary ganglion neurons.
The role of cytosolic Ca2+ in cell injury, necrosis and apoptosis.

Increases in cytosolic Ca2+ are believed to be a pivotal signal in the regulation of cell injury, cell death, cell proliferation, cellular differentiation and cellular aging. Changes in the concentration of cytosolic Ca2+ are involved in both acute and chronic cell injury, as well as in accidental or programmed cell death. Signalling in all of these phenomena is dependent on mediated activities of a number of intracellular factors, including phospholipases, proteases and endonucleases. The coordinate regulation of these factors, as well as of oncogene activation, seems to play a role both in the process of cell injury and cell death, and in the recovery from injury in sublethally injured cells.
The bear paw: A radiologic sign for congenital ureteropelvic junction obstruction

This article defines a new radiographic descriptor of high-grade hydronephrosis suggestive of ureteropelvic junction obstruction that is easily recognized by urologists and non-urologists alike. This is useful information for medical personnel participating in the management of children with hydronephrosis.
Transfer of orbital angular momentum between acoustic and optical vortices in optical fiber

Transfer of orbital angular momentum from an electronically controlled acoustic vortex to an optical vortex in optical fiber is experimentally demonstrated. Potential applications include quantum key encryption and decoding and optical trapping.
Mucus and surfactant synthesis and secretion by cultured hamster respiratory cells.

Procedures for the selective isolation and cultivation in monolayer of respiratory cells have been developed. This technique requires repeated protease treatment and gradient centrifugation of hams...
Malignant atrophic papulosis (Degos’ disease) involving three generations of a family ☆ ☆☆

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Guest Editor's Introduction: Top Picks from the Computer Architecture Conferences of 2009

This special issue is the seventh in an important tradition in the computer architecture community: IEEE Micro's Top Picks from the Computer Architecture Conferences. This tradition, started by IEEE Micro's then editor in chief, Pradip Bose, provides a means for sharing a sample of the best papers published in computer architecture during the past year with the IEEE Micro readership and researchers in the computer architecture community.
Single frame holographic particle image velocimetry

We present a novel method for single frame particle image velocimetry of micron scale spheres based on holographic video microscopy. Our approach takes advantage of the blurring that recorded holograms suffer when a sphere moves during the exposure period of the camera. By measuring the angular variance in intensity of the blurred hologram, we extract a modelindependent metric for the particle velocity. We find this to be accurate for speeds that permit characterization of other properties of the sphere, such as radius and refractive index through Lorenz-Mie mocroscopy. Singl-frame holographic velocimetry yields information on the dynamics of a particle, without sacrificing any other measurements.
Selecting expert system development techniques

Abstract The widespread development of Expert System applications with a wide variety of characteristics raises a risk that development techniques and application types are not properly matched. This could lead to ES development and maintenance problems, and unnecessary costs for the organization. Four widely used ES development techniques are discussed in terms of basic characteristics and their strength and limitations. The appropriate application of each technique is prescribed and the commercially available tools supporting the techniques are presented. IS managers and ES developers can use the information acquired and properly match ES development tools to applications targeted for ES use in their development.
Age-related reduction in pituitary corticotropin-releasing hormone receptors in two rat strains

Abstract Open field behavior and age-related changes in anterior pituitary corticotropin-releasing hormone (CRH) receptors, as well as plasma ACTH levels, were measured in two inbred rat strains. The strains utilized were Wistar Kyoto (WKY) and Brown-Norway (BN), the former characterized by shorter life-span and hyper-reactivity to stressors as compared to the latter. Behaviorally, WKY rats showed hyper-responsivity to a novel environment as indicated by their delay in entering the open field, increased grooming, reduced rearing, and reduced locomotion. These strain-dependent behavioral differences were not affected by aging. The binding capacity of CRH receptors was similar in both strains and Bmax values were decreased (25–27%) with aging, with no changes in Kd values. In contrast, plasma ACTH levels were 67% higher in WKY than in BN rats but did not change with aging. Thus, despite pituitary CRH receptor down regulation, plasma ACTH levels following decapitation were sustained during aging. This suggests the presence of some compensatory factors in the hypothalamic-pituitary axis regulation which sustain ACTH response during aging. Furthermore, the findings indicate that higher plasma ACTH levels and hyper-reactivity to a novel environment are inversely correlated with longevity in the rat.
One protein from two open reading frames: mechanism of a 50 nt translational bypass

Translating ribosomes bypass a 50 nt coding gap in order to fuse the information found in the two open reading frames (ORFs) of bacteriophage T4 gene 60. This study investigates the underlying mechanism by focusing on the competition between initiation of bypassing and termination at the end of the first ORF. While nearly all ribosomes initiate bypassing, no more than 50% resume translation in the second ORF. Two previously described cis-acting stimulatory signals are critical for favoring initiation of bypassing over termination. Genetic analysis of these signals supports a working model in which the first (a stem–loop structure at the junction between the first ORF and the coding gap) interferes with decoding in the A-site, and the second (a stretch of amino acids in the nascent peptide encoded by the first ORF) destabilizes peptidyl-tRNA–mRNA pairing.
Vertebral deformities and fractures are associated with MRI and pQCT measures obtained at the distal tibia and radius of postmenopausal women

Summary We investigated the association of postmenopausal vertebral deformities and fractures with bone parameters derived from distal extremities using MRI and pQCT. Distal extremity measures showed variable degrees of association with vertebral deformities and fractures, highlighting the systemic nature of postmenopausal bone loss.
Pharmacological action of Senecio riddellii.

The administration of the crude alkaloid of Senecio riddellii in mice produced acute intoxication followed by remission, recurrence of symptoms, and death. The toxic dose was determined by intraperitoneal and oral administration of the alkaloid. The feeding of plant produced typical symptoms of chronic poisoning similar to that observed in cattle. The alkaloid‐free resinous residue produced vascular damage in the intestinal tract with subsequent development of gangrene. The injection of the crude alkaloid of Senecio riddellii reduced the vitamin A content of the liver.
Effect of pH on Nonformaldehyde Durable Press Finishing of Cotton Fabric: FT-IR Spectroscopy Study Part II: Formation of the Anhydride Intermediate

Esterification of cotton cellulose by a polycarboxylic acid proceeds in two steps: the formation of a five-member cyclic anhydride intermediate by the dehydration of two adjacent carboxyl groups of the polycarboxylic acid, and the reaction between cellulose and that intermediate to form an ester. We studied the effect of finish bath pH on anhydride intermediate formation using Fourier transform infrared spectroscopy. Our previous research demonstrated that esterification of cellulose by a polycarboxylic acid was not acid-catalyzed. The infrared spectroscopy data presented here indicate that the amount of anhydride intermediate formed in a cotton fabric increases as the finish bath pH decreases from 4.5 to 1.5. Therefore, the formation of the cyclic anhydride intermediate is accelerated by an increase in proton concentration of the finish bath. Anhydride intermediate formation and cellulose esterification show different pH-de pendencies.
Digital signal processing aids cholesterol plaque detection

We describe four new methods for detection of cholesterol plaque deposits inside arteries, using digital signal processing. These methods have been tested on a number of patients. The results obtained are presented and discussed. An ultrasonic beam is directed towards the examined artery. Signal features obtained from the Doppler signal reflected from the bloodstream contain information about the character of turbulences caused by cholesterol deposits inside the artery. These features can thus provide information about the size, shape, and position of stenosis. Features in both the time and frequency domains were utilized, such as the LPC cepstrum, the exponential time-frequency distribution, the energy waveform and the wavelet transform.
The effect of pressure on the magnetic properties of the molecule-based canted metamagnet decamethylferrocenium 2,3-dicyano-1,4-naphthoquinonide, FeCp*2[DCNQ]

Abstract The pseudo-1D charge-transfer salt decamethylferrocenium 2,3-dicyano-1,4-naphthoquinonide, FeCp*2[DCNQ], is an unusual metamagnet that exhibits hysteresis centered on zero applied field in the nominally antiferromagnetically ordered state due to the presence of canting. Measurements of the a.c. susceptibility in a d.c. magnetic field in a He-gas cell up to hydrostatic pressures of 5 kbar have shown an approximately linear increase in both the Neel temperature and the metamagnetic critical field with increasing pressure, consistent with increasing net antiferromagnetic interstack interactions due to decreasing interstack distances.
Phylogenetic Analysis of the Bacterial Communities in Marine Sediments

For the phylogenetic analysis of microbial communities present in environmental samples microbial DNA can be extracted from the sample, 16S rDNA can be amplified with suitable primers and the PCR, and clonal libraries can be constructed. We report a protocol that can be used for efficient cell lysis and recovery of DNA from marine sediments. Key steps in this procedure include the use of a bead mill homogenizer for matrix disruption and uniform cell lysis and then purification of the released DNA by agarose gel electrophoresis. For sediments collected from two sites in Puget Sound, over 96% of the cells present were lysed. Our method yields high-molecular-weight DNA that is suitable for molecular studies, including amplification of 16S rRNA genes. The DNA yield was 47 micrograms per g (dry weight) for sediments collected from creosote-contaminated Eagle Harbor, Wash. Primers were selected for the PCR amplification of (eu)bacterial 16S rDNA that contained linkers with unique 8-base restriction sites for directional cloning. Examination of 22 16S rDNA clones showed that the surficial sediments in Eagle Harbor contained a phylogenetically diverse population of organisms from the Bacteria domain (G. J. Olsen, C. R. Woese, and R. Overbeek, J. Bacteriol. 176:1-6, 1994) with members of six major lineages represented: alpha, delta, and gamma Proteobacteria; the gram-positive high G+C content subdivision; clostridia and related organisms; and planctomyces and related organisms. None of the clones were identical to any representatives in the Ribosomal Database Project small subunit RNA database. The analysis of clonal representives in the first report using molecular techniques to determine the phylogenetic composition of the (eu)bacterial community present in coastal marine sediments.
Comparing the performance parameters of two network structures for scalable massively parallel processors

Packed exponential connection (PEC) networks and periodically regular chordal (PRC) rings, proposed as enhanced versions of linear arrays and rings respectively introduce skip links into the respective base networks. Both networks can be viewed as derivatives of symmetric chordal rings with restricted or reduced connection assignments. Thus, an interesting question arises: How can one prune or thin the connections of a given network to a prescribed degree such that the key network properties are still acceptable? We show the hierarchical arrangements and grouping strategies on which PEC networks and PRC rings are based and examine their effects on expandability, ease of implementation, network diameter, and routing schemes.
Hereditary Aplasia Cutis Congenita and Associated Defects Three Instances in One Family and a Survey of Reported Cases

Hereditary aplasia cutis congenita (ACC) is a rare, dominantly inherited syndrome of scalp aplasia associated with defects of the underlying skull and absent distal phalanges of the feet. The scalp lesions are generally benign, but the increased risk of bleeding or meningitis may require skin grafting.
Airborne measurements of stratospheric constituents over the Arctic in the winter of 1989

A Fourier transform spectrometer aboard the NASA DC-8 aircraft was used during the Airborne Arctic Stratospheric Expedition (AASE) to record infrared absorption spectra of the polar stratosphere. From these high resolution spectra, vertical column amounts above flight altitude were derived of O3, CH4, N2O, H2O, HCl, HF, NO, NO2, ClONO2, and HNO3 for eleven flights poleward of 60 deg N. In this paper, measurements on the flight of January 26, 1989 were derived when the flight path during the observations crossed from outside the polar vortex to inside. This allowed a clear comparison of the conditions of the air within the vortex with that outside. Observations of passive tracers such as CH4 and HF indicate that air of a certain composition within the polar vortex occurs at lower altitude than air outside. Within the vortex, markedly reduced columns of HCl and NO2. The ratio of HCl to HF column dropped from its typical midlatitude value of 4.5 to as low as 1.7 within the vortex, implying that the HCl had been chemically or physically removed from the air in the vortex. In contrast to the Antarctic observations, HNO3 values were elevated within the vortex.
Bilateral and Unilateral Antennal Lesions Alter Orientation Abilities of the Crayfish, Orconectes rusticus

Numerous animals use chemical cues within their environments to execute various behaviors. One of these behaviors is orientation to an odor source. Crayfish, in particular, can orient to food sources under a number of different conditions. It has not been determined, however, what kind of search strategy these animals employ to successfully locate a food source. To determine the role of antennae and antennules in this behavior and to investigate different modes of orientation behavior, the orientation patterns of crayfish with complete and partial antennal lesions were examined. Detailed analysis of orientation paths confirmed that crayfish could not locate odor sources with either bilateral or unilateral lesions. This suggests that crayfish are using the spatial information obtained from these appendages to successfully orient. Animals using information from the bilaterally paired appendages in the control group exhibited increased walking speed, increased speed to source and decreased heading angles towards the source compared to these measurements taken from lesioned groups. There was no significant difference in any parameters between animals with unilateral or bilateral lesions. This strongly suggests that these animals are reliant on the spatial comparison of differences between bilaterally paired olfactory appendages for successful orientation.
Comparative sensitivity of five species of macrophytes and six species of algae to atrazine, metribuzin, alachlor, and metolachlor

This data relates to the relative sensitivity of five species of aquatic macrophytes and six species of algae to four commonly used herbicides (atrazine, metribuzin, alachlor, and metoachlor). Toxicity tests consisted of 96 hour (duckweed and algae) or 14 day (submerged macrophytes) static exposures. The triazine herbicides (atrazine and metribuzin) were significantly more toxic to aquatic plants than were the acetanilide herbicides (alachlor and metolachlor). Toxicity studies ranked metribuzin > atrazine > alachlor > metolachlor in decreasing order of overall toxicity to aquatic plants. Relative sensitivities of macrophytes to thse herbicides decreased in the order of Ceratophyllum > Najas > Elodea > Lemna > Myriophyllum. Relative sensitivities of algae to herbicides decreased in the order of Selenastrum > Chlorella > Chlamydomonas > Microcystis > Scenedesmus > Anabaena. Algae and macrophytes were of similar overall sensitivities to herbicides. Data indicated that Selenastrum, a commonly tested green alga, was generally more sensitive compared to other plant species. Lemna minor, a commonly tested floating vascular plant, was of intermediate sensitivity, and was fivefold less sensitive than Ceratophyllum, which was the most sensitive species tested. The results indicated that no species was consistently most sensitive, and that a suite of aquatic plant test species may be needed to perform accurate risk assessments of herbicides.
Linking phenological shifts to species interactions through size-mediated priority effects

Summary 1. Interannual variation in seasonal weather patterns causes shifts in the relative timing of phenological events of species within communities, but we currently lack a mechanistic understanding of how these phenological shifts affect species interactions. Identifying these mechanisms is critical to predicting how interannual variation affects populations and communities. 2. Species’ phenologies, particularly the timing of offspring arrival, play an important role in the annual cycles of community assembly. We hypothesize that shifts in relative arrival of offspring can alter interspecific interactions through a mechanism called size-mediated priority effects (SMPE), in which individuals that arrive earlier can grow to achieve a body size advantage over those that arrive later. 3. In this study, we used an experimental approach to isolate and quantify the importance of SMPE for species interactions. Specifically, we simulated shifts in relative arrival of the nymphs of two dragonfly species to determine the consequences for their interactions as intraguild predators. 4. We found that shifts in relative arrival altered not only predation strength but also the nature of predator–prey interactions. When arrival differences were great, SMPE allowed the early arriver to prey intensely upon the late arriver, causing exclusion of the late arriver from nearly all habitats. As arrival differences decreased, the early arriver’s size advantage also decreased. When arrival differences were smallest, there was mutual predation, and the two species coexisted in similar abundances across habitats. Importantly, we also found a nonlinear scaling relationship between shifts in relative arrival and predation strength. Specifically, small shifts in relative arrival caused large changes in predation strength while subsequent changes had relatively minor effects. 5. These results demonstrate that SMPE can alter not only the outcome of interactions but also the demographic rates of species and the structure of communities. Elucidating the mechanisms that link phenological shifts to species interactions is crucial for understanding the dynamics of seasonal communities as well as for predicting the effects of climate change on these communities.
Learning Enhances the Survival of New Neurons beyond the Time when the Hippocampus Is Required for Memory

Trace memories are formed when a stimulus event becomes associated with another event that occurs later in time and is discontinuous with the first event. The formation of trace memories enhances the survival of newly generated neurons in the dentate gyrus of the adult hippocampus (Gould et al., 1999a). Here we tested whether the acquisition of trace memories early during training is sufficient to enhance cell survival. We also examined whether the new neurons affected by trace memory formation persist indefinitely or only as long as the hippocampus is necessary for the expression of those memories. Groups of adult rats were injected with bromodeoxyuridine (BrdU), a marker of dividing cells, and trained 1 week later with paired stimuli using a trace eyeblink conditioning task or exposed to the same number of unpaired stimuli. Cell survival was assessed after different numbers of training trials and survival periods after training. Overall cell survival was not enhanced by exposure to 200 trials of paired stimuli during trace conditioning. However, there was a positive correlation between performance of individual animals and cell survival. In addition, exposure to 800 trials of paired stimuli during trace conditioning increased the number of BrdU-labeled cells 60 d after training. The vast majority of these cells were neurons and coexpressed the neuronal markers class III-tubulin or neuronal nuclei. These data suggest that individual differences in associative learning predict whether new neurons will survive and that once affected, these neurons remain for months and beyond the time when they are required for the retention of trace memories.
WATER SOURCES USED BY DIDYMOPANAX PITTIERI AT DIFFERENT LIFE STAGES IN A TROPICAL CLOUD FOREST

The water sources used by epiphytic, hemiepiphytic, and arborescent life stages of Didymopanax pittieri were investigated in the tropical cloud forest reserve at Monteverde, Costa Rica. Each life stage was hypothesized to obtain its water from a different location because of differences in terms of where each stage placed its roots. Stable hydrogen isotope analyses of source and plant water samples confirmed that when plants were epiphytic they used water from canopy mats and from occult precipitation (mist, cloud water, and fog) while the arborescent life stage used only water in the soil from recent rainfall; the hemiepiphytic life stage used a mixture of these different water sources. These data demonstrate that along with changes in the life stage of this plant species come changes in its patterns of resource utilization. The generality of this finding for other tropical hemiepiphytes needs to be investigated.