cssi/SciSciGPT-SciSciNet huggingface dataset:
The intrinsic ATPase activity of Mycobacterium tuberculosis DnaA promotes rapid oligomerization of DnaA on oriC.

Summary Oligomerization of the initiator protein, DnaA, on the origin of replication ( oriC ) is crucial for initiation of DNA replication . Studies in Escherichia coli (Gram- negative) have revealed that binding of DnaA to ATP, but not hydrolysis of ATP, is sufficient to promote DnaA binding, oligomerization and DNA strand separation. To begin understanding the initial events involved in the initiation of DNA replication in Myco- bacterium tuberculosis (Gram-positive), we investi- gated interactions of M. tuberculosis DnaA (DnaA TB ) with oriC using surface plasmon resonance in the presence of ATP and ADP. We provide evidence that, in contrast to what is observed in E. coli , ATPase activity of DnaA TB promoted rapid oligomerization on oriC. In support, we found that a recombinant mutant DnaA TB proficient in binding to ATP, but deficient in ATPase activity, did not oligomerize as rapidly. The corresponding mutation in the dnaA gene of M. tuberculosis resulted in non-viability, presumably due to a defect in oriC -DnaA interactions. Dimethy sulphate (DMS) footprinting experiments revealed that DnaA TB bound to DnaA boxes similarly with ATP or ADP. DnaA TB binding to individual DnaA boxes revealed that rapid oligomerization on oriC is trig- gered only after the initial interaction of DnaA with individual DnaA boxes. We propose that ATPase activ- ity enables the DnaA protomers on oriC to rapidly form oligomeric complexes competent for replication initiation.
Genetics of interventional cardiology. Old principles, new frontiers.

The Master said, “ By nature, men are nearly alike; by practice, they get to be wide apart. ” —Confucius, Analects The origin of cardiovascular disorders, as of all disease, lies in the duality of inborn predisposition, or susceptibility, and the exposure to external (environmental) influences. We apply this knowledge in our daily clinical practice as we consider anamnestic data from a patient’s family history as well as from his or her lifestyle and occupation in our assessment of cardiovascular risk. We also commonly draw a connection between these two etiologic domains, simplistic as it may be, by estimating a proportionately higher risk in the presence of “positive” findings from both categories. At the same time, we are keenly aware of how vague and inaccurate prognostications remain that are based on these recognized risk factors and how little specific guidance for the management of individual patients they offer. Is it possible that more detailed knowledge of the genetic component of a patient’s “risk profile” might raise the precision and specificity of our risk assessment and thus improve the success rate of intervention? To the geneticist, the specific, not simply additive, interaction between inherited characteristics and environmental factors is a well-appreciated phenomenon: neither exposure to dietary phenylalanine nor a defect in the gene encoding phenylalanine hydroxylase is by itself associated with disease, yet the combination of the two results in the severe syndrome of pronounced mental retardation and associated somatic abnormalities typical of phenylketonuria. We may expect that in other diseases that show the markings of both inherited and acquired disorders, similar specific “ecogenetic” interactions between external influences and genetic mutations exist that predict with a high degree of specificity an individual’s response or disease susceptibility to an environmental exposure. Complex diseases, which encompass most cardiovascular as well as other epidemiologically …
Comparison of refractometer and biuret methods for total protein measurement in body cavity fluids.

Most hand-held medical refractometers have internal scales that limit protein measurement to results >/=2.5 g/dL. Tables for conversion of refraction (r) to protein concentration for values as low as 0.1 g/dL were published in the 1960s, but their accuracy for use on body fluids has not been established. The purpose of this study was to assess the reliability of body cavity fluid protein determination by refractometry. We compared the protein concentration of 25 body cavity fluids as determined by 2 Goldberg type hand-held refractometers with results obtained by the biuret method. Published charts converting refraction (r) to protein concentration were used to determine protein concentration in samples with protein /=0.6 g/dL, the lowest concentration of the biuret method's standard curve. Twenty-one peritoneal fluid, 2 pleural fluid and 2 pericardial fluid samples from 16 horses, 5 cattle, 3 dogs, 2 llamas and 1 cat were tested. The results obtained by the two refractometers were closely and linearly related to biuret results (P 0.977. Based on this study, the range for quantification of body cavity fluid protein concentration by refractometry can be extended below 2.5 g/dL, allowing for quantitative assessment of most clinical samples.
DNA methyltransferases are required to induce heterochromatic re-replication in Arabidopsis.

The relationship between epigenetic marks on chromatin and the regulation of DNA replication is poorly understood. Mutations of the H3K27 methyltransferase genes, ARABIDOPSIS TRITHORAX-RELATED PROTEIN5 (ATXR5) and ATXR6, result in re-replication (repeated origin firing within the same cell cycle). Here we show that mutations that reduce DNA methylation act to suppress the re-replication phenotype of atxr5 atxr6 mutants. This suggests that DNA methylation, a mark enriched at the same heterochromatic regions that re-replicate in atxr5/6 mutants, is required for aberrant re-replication. In contrast, RNA sequencing analyses suggest that ATXR5/6 and DNA methylation cooperatively transcriptionally silence transposable elements (TEs). Hence our results suggest a complex relationship between ATXR5/6 and DNA methylation in the regulation of DNA replication and transcription of TEs.
Nanomechanical Probes of Single Corneal Epithelial Cells: Shear Stress and Elastic Modulus

Living human corneal epithelial cells have been probed in vitro via atomic force microscopy, revealing the frictional characteristics of single cells. Under cell media, measured shear stresses of 0.40 kPa demonstrate the high lubricity of epithelial cell surfaces in contact with a microsphere probe. The mechanical properties of individual epithelial cells have been further probed through nanometer scale indentation measurements. A simple elastic foundation model, based on experimentally verifiable parameters, is used to fit the indentation data, producing an effective elastic modulus of 16.5 kPa and highlighting the highly compliant nature of the cell surface. The elastic foundation model is found to more accurately fit the experimental data, to avoid unverifiable assumptions, and to produce a modulus significantly higher than that of the widely used Hertz–Sneddon model.
Fatty acid acylation of salivary mucin in rat submandibular glands.

Abstract The acylation of salivary mucin with fatty acids and its biosynthesis was investigated by incubating rat submandibular salivary gland cells with [ 3 H]palmitic acid and [ 3 H]proline. The elaborated extracellular and intracellular mucus glycoproteins following delipidation, Bio-Gel P-100 chromatography, and CsCl equilibrium density gradient centrifugation were analyzed for the distribution of the labeled tracers. Both preparations gave single bands at the CsCl density of 1.48, in which carbohydrate peaks coincided with that of the labels. The [ 3 H]palmitic acid in these glycoproteins was susceptible to cleavage by alkali and hydroxylamine, thus indicating the ester nature of the bond. With both intracellular and extracellular glycoproteins deacylation caused the glycoproteins to band in the CsCl gradient at a density of 1.55. The incorporation of both markers into mucus glycoprotein increased steadily with time up to 4 h, at which time about 65% of [ 3 H]palmitate and [ 3 H]proline were found in the extracellular glycoprotein and 35% in the intracellular glycoprotein. The incorporation ratio of proline/ palmitate, while showing an increase with incubation time in the extracellular glycoprotein, remained essentially unchanged with time in the intracellular glycoprotein and at 4 h reached respective values of 0.14 and 1.12. The fact that the proline/palmitate incorporation ratio in the intracellular glycoprotein at 1 h of incubation was 22 times higher than in the extracellular and 8 times higher after 4 h suggests that acylation occurs intracellularly and that fatty acids are added after apomucin polypeptide synthesis. As the incorporation of palmitate within the intracellular mucin was greater in the mucus glycoprotein subunit, it would appear that fatty acid acylation of mucin subunits preceeds their assembly into the mucus glycoprotein polymer.
Evaluation and Analysis of Attenuated Total Reflectance FT-IR Spectra Using Kramers-Kronig Transforms

Two commonly used correction algorithms that were originally developed by Bertie and Dignam and their co-workers for quantitative analysis of ATR spectra are examined. It is shown that the Dignam theory is more suitable for strong ATR bands, whereas the Bertie algorithm is more applicable for weak bands. On the basis of analysis of possible deviation sources determined in the Bertie and Dignam theories, a new ATR algorithm is developed and analyzed. With this approach, the initial estimate of the absorption index spectrum is obtained by KK correlation of the intensity and the phase of the complex Fresnel reflection coefficient. An iterative process that minimizes the difference between the true and calculated reflectivity spectra while maintaining the KK relation between refractive and absorption indices is used in conjunction with the Maclaurin numerical KKT method. Such an approach appears to improve accuracies for both weak and strong ATR bands.
Moderate-resolution study of the two-photon spectrum of the 1B2u state of benzene-h6 and benzene-d6

Abstract The two-photon absorption spectra at ≈ 2 cm −1 resolution is presented for benzene- h 6 and benzen- d 6 . A number of vibrations of b 1u , b 2u , e 1u and c 2u symmetry are assigned and the results compared with theoretical expectations. It appears as if the π-electron states dominate the coupling to the radiation in causing the two-photon transitions.
High‐resolution image of Calaveras Fault seismicity

[1] By measuring relative earthquake arrival times using waveform cross correlation and locating earthquakes using the double difference technique, we are able to reduce hypocentral errors by 1 to 2 orders of magnitude over routine locations for nearly 8000 events along a 35-km section of the Calaveras Fault. This represents ∼92% of all seismicity since 1984 and includes the rupture zone of the M 6.2 1984 Morgan Hill, California, earthquake. The relocated seismicity forms highly organized structures that were previously obscured by location errors. There are abundant repeating earthquake sequences as well as linear clusters of earthquakes. Large voids in seismicity appear with dimensions of kilometers that have been aseismic over the 30-year time interval, suggesting that these portions of the fault are either locked or creeping. The area of greatest slip in the Morgan Hill main shock coincides with the most prominent of these voids, suggesting that this part of the fault may be locked between large earthquakes. We find that the Calaveras Fault at depth is extremely thin, with an average upper bound on fault zone width of 75 m. Given the location error, however, this width is not resolvably different from zero. The relocations reveal active secondary faults, which we use to solve for the stress field in the immediate vicinity of the Calaveras Fault. We find that the maximum compressive stress is at a high angle, only 13° from the fault normal, supporting previous interpretations that this fault is weak.
Radiation from Cerenkov Wakes in a Magnetized Plasma

The Cerenkov wake excited by a particle beam or a short laser pulse in a perpendicularly magnetized plasma is analyzed. The wake couples to electromagnetic radiation of approximate frequency {omega}{sub p} at the plasma/vacuum boundary. The radiation amplitude is {omega}{sub c}/{omega}{sub p} times the amplitude of the wake excited in the plasma (for a sharp boundary). Particle-in-cell simulations verify the scaling laws. Since plasma wakes as high as a few GeV/m are produced in current experiments, the potential for a high-power (i.e., GW) coherent microwave to THz radiation source exists. {copyright} {ital 1997} {ital The American Physical Society}
Monotone method and convergence acceleration for finite‐difference solutions of parabolic problems with time delays

In this article we study a finite-difference system, which is a discrete version of a class of nonlinear reaction-diffusion systems with time delays. Existence-comparison and uniqueness theorem are first established for the discretized problem by the method of upper and lower solutions. A monotone iterative scheme is also developed for the solution of the finite-difference system. Under a convergence acceleration scheme, it is shown that the monotone sequences converge quadratically to the solution of the finite-difference system. At last, numerical results on some model problems are demonstrated to substantiate our theorems. © 1995 John Wiley & Sons, Inc.
Marine ecology — some chemical aspects

Relationships among biota on tropical coral reefs are frequently governed by chemical phenomena. This article describes some of the ecological events that may lead to a human intoxication known as ciguatera, and a few examples of the survival strategy that is used by physically unprotected gastropod mollusks.
70Z/3 Cbl induces PLC gamma 1 activation in T lymphocytes via an alternate Lat- and Slp-76-independent signaling mechanism.

70Z/3 Cbl induces PLC γ 1 activation in T lymphocytes via an alternate Lat- and Slp-76-independent signaling mechanism
Florigen: One Found, More to Follow?

Florigen(s) are molecules that are synthesized in response to appropriate photoperiods and transmitted from leaves to shoot apices to promote floral initiation. It has been recently discovered in Arabidopsis that mRNA of the FT gene acts as a florigen. In Arabidopsis, cryptochromes and phytochromes mediate long-day promotion of CO protein expression, which activates FT mRNA expression in leaves. FT mRNA is transmitted to the shoot apex, where it acts together with FD to activate transcription of floral meristem identity genes, resulting in floral initiation. The discovery of the molecular nature of a florigen was a major scientific breakthrough in 2005. (Managing editor: Li-Hui Zhao)
Massive Hematochezia: A Complication of Methamphetamine-Induced Vasculitis Treated by Transcatheter Hemostasis

A long-term, heavy methamphetamine user with life-threatening rectal hemorrhage was treated with transcatheter occlusion of the bleeding arteries. The bleeding blood vessels were vulnerable submucosal arteries, part of the collateral supply to the distal colon. Visceral arteriography demonstrates severe arterial stenotic lesions of the celiac axis, superior mesenteric artery and the inferior mesenteric artery. Collateral vessels were seen with corkscrew morphology similar to that seen with thromboangiitis obliterans.
Indicating the body: Expression of body part terminology in American Sign Language

This article inventories and examines the articulation of body part terms in American Sign Language (ASL). The question of whether ASL primarily relies on the pointing gesture to refer to body parts underlies this investigation. Results indicate that the pointing gesture insufficiently captures the complexity of the human representation of the body. Through regular phonological contrasts, ASL encodes a systematic categorization of the body that is based on body part size, internal vs. external body parts, and proximal vs. distal body parts. Some body signs in ASL incorporate the 1-Hand handshape, which shares its form with that of the pointing gesture. Signers differentiate body part labels from the pointing gesture by reduplicating movement toward the indexed body part, mouthing the English body part term, or supplementing the index with the fingerspelled English term.
Growth of myoblasts in lipoprotein-supplemented, serum-free medium: Regulation of proliferation by acidic and basic fibroblast growth factor

BC3H1 myoblast cells seeded at low density on gelatin-coated dishes and exposed to a 1∶1 (vol/vol) mixture of Dulbecco’s modified Eagle’s medium and Ham’s F12 medium, proliferate actively when exposed to high density lipoproteins (HDL), transferrin, insulin, and basic or acidic fibroblast growth factor (FGF). This serum-free medium combination supported cell multiplication at a rate equal to that of serum-supplemented medium, and at low cell input (103 cells/35-mm dish). It also allowed serial transfer of the cultures under serum-free conditions. HDL seems to promote cell survival and to act as progression factor allowing cells to divide when exposed to either basic or acidic FGF. When the potency of basic and acidic FGF were compared, acidic FGF was 20-fold less potent than basic FGF.
Ligand Entry and Exit Pathways in the β2-adrenergic Receptor

The recently determined crystal structure of the human beta(2)-adrenergic (beta(2)AR) G-protein-coupled receptor provides an excellent structural basis for exploring beta(2)AR-ligand binding and dissociation process. Based on this crystal structure, we simulated ligand exit from the beta(2)AR receptor by applying the random acceleration molecular dynamics (RAMD) simulation method. The simulation results showed that the extracellular opening on the receptor surface was the most frequently observed egress point (referred to as pathway A), and a few other pathways through interhelical clefts were also observed with significantly lower frequencies. In the egress trajectories along pathway A, the D192-K305 salt bridge between the extracellular loop 2 (ECL2) and the apex of the transmembrane helix 7 (TM7) was exclusively broken. The spatial occupancy maps of the ligand computed from the 100 RAMD simulation trajectories indicated that the receptor-ligand interactions that restrained the ligand in the binding pocket were the major resistance encountered by the ligand during exit and no second barrier was notable. We next performed RAMD simulations by using a putative ligand-free conformation of the receptor as input structure. This conformation was obtained in a standard molecular dynamics simulation in the absence of the ligand and it differed from the ligand-bound conformation in a hydrophobic patch bridging ECL2 and TM7 due to the rotation of F193 of ECL2. Results from the RAMD simulations with this putative ligand-free conformation suggest that the cleft formed by the hydrophobic bridge, TM2, TM3, and TM7 on the extracellular surface likely serves as a more specific ligand-entry site and the ECL2-TM7 hydrophobic junction can be partially interrupted upon the entry of ligand that pushes F193 to rotate, resulting in a conformation as observed in the ligand-bound crystal structure. These results may help in the design of beta(2)AR-targeting drugs with improved efficacy, as well as in understanding the receptor subtype selectivity of ligand binding in the beta family of the adrenergic receptors that share almost identical ligand-binding pockets, but show notable amino acid sequence divergence in the putative ligand-entry site, including ECL2 and the extracellular end of TM7.
Fix and flap in the era of vacuum suction devices: What do we know in terms of evidence based medicine?

Abstract Introduction The concept of immediate or early fixation and soft tissue coverage of open fractures is frequently referred to as ‘fix and flap,’ and negative pressure wound therapy (NPWT) has had a major impact in this area. This article aims to review concepts and evidence relevant to the use of NPWT in open fractures. Review of open fracture management Muscle flaps in open fractures do well in part because they improve blood supply to the underlying fracture. Outcomes of muscle flaps are best when done acutely, before bacterial colonisation. The colonised subacute wound is managed with ‘open-wound techniques’ until it becomes a chronic localised wound, when flap coverage is again indicated. NPWT provides a useful adjunct in this process as the zone of injury is determined. Vacuum-assisted closure: review of basic and clinical science literature Proposed mechanisms of action of NPWT include: increased blood flow, decreased oedema, cytokine release induced by mechanical stretch and increased lactate and oxygen tension in the tissue with induction of collagen transcription and angiogenesis. Vacuum-assisted closure in open fractures NPWT to open fractures caused early appearance of healthy granulation tissue, a reduction in wound area and allowed simpler soft tissue procedures for wound closure. NPWT also improved clinical survival of muscle flaps despite occluded flap venous outflow. Summary The aim in open fractures is to stabilize the fracture and achieve soft tissue coverage before infection develops. NPWT, applied as a temporizing dressing, simplifies soft tissue coverage on the ‘reconstructive ladder.’ The only Level-I data on that topic showed a significant decrease in infections. However, NPWT does not allow delay in soft tissue coverage. NPWT increases the ‘take rate’ of skin grafts, skin substitutes and composite skin grafts and allows quicker graft incorporation.
Grain boundary effects in polycrystalline silicon solar cells II: Numerical calculation of the limiting parameters and maximum efficiency

Abstract Extensive numerical calculations have been made of the photocurrent, the dark current and the fill factor for n-p junction polycrystalline silicon solar cells utilizing our previously developed theory in three dimensions. Various grain boundary effects such as grain boundary recombination velocity, grain size and grain orientations were considered. It has been shown that for zero grain boundary effect the current-voltage characteristics, fill factor and efficiency approach the single-crystal limit. For polycrystalline silicon solar cells it has been demonstrated that an efficiency of about 15% could be produced with fibrously grained samples of grain size 100 μm, recombination velocity 100 m s−1 and thickness 100 μm.
Weak-boson production at Fermilab Tevatron energies.

Weak bosons are produced in hadron collisions by quarks and antiquarks withaverage fractional momenta /ital x/=/ital M//sub /ital W/,/ital Z/// /radical/s . When /radical//ital s/is increased by a factor of 3, the average value of /ital x/ shifts fromabout 0.15 at CERN /ital pp/bar // collider energies to 0.05 at the FermilabTevatron, i.e., from a regime where valence quarks dominate to a regime wheresea quarks dominate the production features of weak bosons. We investigatesystematically the problem of calculating /ital W/ and /ital Z/ cross sections inthis new regime, paying special attention to the ratio/sigma/(/ital W/)//sigma/(/ital Z/) which is necessary for determining the ratio oftotal widths /Gamma/(/ital W/)//Gamma/(/ital Z/) from hadron-collider data. Weemphasize that with the increased statistics in /ital pp/bar // experiments, theparton fluxes responsible for the production of weak bosons can be controlledinternally by a study of the asymmetry of the rapidity distribution of the/ital W/ boson. We derive a relation between the asymmetry in /ital W//sup /plus minus//rapidity distributions and the ratio/ital F//sub 2//sup /ital n///F/sub 2//sup p/ of deep-inelastic lepton-hadronscattering structure functions. The production rates of weak bosons also becomesensitive to production via the charm quark. This calculation raises someinteresting theoretical issues. We discuss both problems inmore » detail. We alsostudy the implications of our results for the determination of the number oflight neutrinos and the mass of the top quark via a measurement of the/ital W/-to-/ital Z/ event ratio.« less
Cathepsin B-sensitive polymers for compartment-specific degradation and nucleic acid release.

Abstract Degradable cationic polymers are desirable for in vivo nucleic acid delivery because they offer significantly decreased toxicity over non-degradable counterparts. Peptide linkers provide chemical stability and high specificity for particular endopeptidases but have not been extensively studied for nucleic acid delivery applications. In this work, enzymatically degradable peptide-HPMA copolymers were synthesized by RAFT polymerization of HPMA with methacrylamido-terminated peptide macromonomers, resulting in polymers with low polydispersity and near quantitative incorporation of peptides. Three peptide-HPMA copolymers were evaluated: (i) pHCathK 10 , containing peptides composed of the linker phe-lys-phe-leu (FKFL), a substrate of the endosomal/lysosomal endopeptidase cathepsin B, connected to oligo-( l )-lysine for nucleic acid binding, (ii) pHCath( d )K 10 , containing the FKFL linker with oligo-( d )-lysine, and (iii) pH( d )Cath( d )K 10 , containing all ( d ) amino acids. Cathepsin B degraded copolymers pHCathK 10 and pHCath( d )K 10 within 1 h while no degradation of pH( d )Cath( d )K 10 was observed. Polyplexes formed with pHCathK 10 copolymers show DNA release by 4 h of treatment with cathepsin B; comparatively, polyplexes formed with pHCath( d )K 10 and pH( d )Cath( d )K 10 show no DNA release within 8 h. Transfection efficiency in HeLa and NIH/3T3 cells were comparable between the copolymers but pHCathK 10 was less toxic. This work demonstrates the successful application of peptide linkers for degradable cationic polymers and DNA release.
Double-Strand Break Repair Deficiency and Radiation Sensitivity in BRCA2 Mutant Cancer Cells

Background: The protein product of the BRCA2 gene mediates repair of double-strand breaks in DNA. Because a number of cancer therapies exert cytotoxic effects via the initiation of double-strand breaks, cancers comprised of cells carrying BRCA2 gene mutations may be more amenable to treatment with agents that cause such breaks. Methods: We identified a human pancreatic adenocarcinoma cell line lacking one copy of the BRCA2 gene and containing a mutation (6174delT) in the remaining copy. In vitro and in vivo experiments were conducted with this cell line and with other carcinoma cell lines matched for similar genetic mutations, similar differentiation status, and/or similar carcinoma type to examine double-strand break repair, sensitivity to drugs that induce double-strand breaks, and radiation sensitivity. Results: BRCA2-defective cells were unable to repair the double-strand DNA breaks induced by ionizing radiation. These cells were also markedly sensitive to mitoxantrone, amsacrine, and etoposide (drugs that induce double-strand breaks) (two-sided P = .002) and to ionizing radiation (two-sided P = .001). Introduction of antisense BRCA2 deoxyribonucleotides into cells possessing normal BRCA2 function led to increased sensitivity to mitoxantrone (two-sided P = .008). Tumors formed by injection of BRCA2defective cells into nude mice were highly sensitive (>90% tumor size reduction, two-sided P = .002) to both ionizing radiation and mitoxantrone when compared with tumors exhibiting normal BRCA2 function. Histologic analysis of irradiated BRCA2-defective tumors showed a large degree of necrosis compared with that observed for control tumors possessing normal BRCA2 function. Conclusion: BRCA2defective cancer cells are highly sensitive to agents that cause double-strand breaks in DNA. [J Natl Cancer Inst 1998;90: 978‐85]
Metabolic products of arachidonic acid in rats.

Abstract The pattern of eicosanoid metabolites appearing in urine and feces following oral administration of radioactive arachidonic acid was investigated using rats deficient in essential fatty acids. About 70–80% of the radioactivity in the urine during the first day after feeding was adsorbed to XAD-2 resin and he represented eicosanoid metabolites, whereas the rest of the radioactivity was mainly 3H2O. The eicosanoid metabolites were fractioned into different polarity classes using reverse phase Sep-Pak C18 cartridges. Gas chromatographic analysis of the urinary metabolites following their derivatization into methyl ester-methoxime- tert -butyl-dimethylsilyl ethers revealed that nearly one-half of the metabolites had ECL values less than 22 and represented metabolites more oxidized than commonly described. Only 30% of the metabolites had ECL values between 26 to 32, corresponding to the values for the metabolites that originate from exogenously infused prostaglandins. A large portion of the eicosanoid metabolites was also excreted with the feces. The isotropic patterns from the reverse phase chromatography indicated that many of the fecal metabolites may be similar to those in urine although some metabolites in feces were not present in urine. Based on the specific radioactivity of the administered arachidonic acid, it appeared that at least 6 to 8 mg of eicosanoid metabolites were excreted through urine and feces within 24 hrs following an oral bolus of 60 mg arachidonic acid. The rapid increase and subsequent decrease in eicosanoid metabolite excretion after oral administration of arachidonate indicates that the dietary intake of polyunsaturated fatty acids may have a more rapid effect upon the endogenous production of eicosanoids than is generally recognized.
Opinion: Lay summaries needed to enhance science communication

At first blush, the notion of lay summaries seems a simple idea with admirable aims: Scientists write summaries of journal articles emphasizing the broad significance of research in accessible language. However, viewed from an ivory tower that has been besieged by an increasing amount of paperwork, scientists could easily regard lay summaries as just one more hurdle in peer-reviewed publishing, another administrative task to fit into an already busy agenda. But rather than an unrewarding burden, scientists (and journal publishers) should consider widespread adoption of lay summaries—accompanying online publications and made publicly available with traditional abstracts—as a way to increase the visibility, impact, and transparency of scientific research. This is a particularly important undertaking given the changing science media landscape. There are clear professional benefits to increasing visibility of one’s own research through broad communication. Disparate studies show consistent connections between public communication, increased visibility of research, and greater numbers of citations (e.g., refs. 1 and 2). Concerns voiced by scientists that public communication is time-consuming, too difficult, and even professionally risky (3) contrast strongly with research documenting that scientists who engage in public communication enjoy an enhanced reputation among peers, and rate contacts with media as generally positive and beneficial to their careers (2, 4). Furthermore, scientists who engage in public communication tend to be more academically productive; few experience negative career impacts from these activities (5). Journalists also value and cultivate connections with scientists who can communicate clearly and accessibly (6). At best, scientists could view lay summaries as opportunities to contextualize their research and communicate with interested nonspecialists. But regardless, they could serve as building blocks for broad and transparent communication of research. The value of lay summaries increases when considered within the radically changing science media landscape. There is little debate that dissemination of research … [↵][1]1To whom correspondence should be addressed. Email: olden{at}uw.edu. [1]: #xref-corresp-1-1
Exchange rates forecasting: local or global methods?

Exchange rates forecasters usually assume that local methods (nearest neighbour) dominate the global ones (neural networks or genetic programming, for example). In this article, first, we use different generalizations of the standard nearest neighbours to predict the dynamic evolution of the Yen/US$ and Pound Sterling/US$ exchange rates one-period ahead. Second, we compare our results with those employing global methods such as neural networks, genetic programming, data fusion and evolutionary neural networks. Finally, we find out the existence of predictable structures τ periods ahead. Our results reveal a slightly but significant forecasting ability for one-period ahead which is lost when more periods ahead are considered, and no important predictive differences between local and global methods have been found.
Online Vibration Monitoring Of Ball Bearing Damage Using an Experimental Test Rig

Rolling element bearings in rotating machinery are vulnerable mechanical components that are prone to premature failure with dire consequences. Early warning of impending bearing failures is vital to the safety and reliability of high-speed turbomachinery. At present, vibration monitoring is one of the most common procedures used to detect online damage and early failure of rolling element bearings. This paper presents results from an experimental rotor-bearing test rig with known induced damage in the supporting ball bearings. Two types of damages are examined, namely, that of 1) the ball rolling element and 2) the inner race of the bearing. Four online vibration signature analyzing schemes are used: 1) time averaging, 2) frequency domain analysis, 3) joint time-frequency analysis (Wigner-Ville and wavelet transforms), and 4) chaotic vibration analysis (modified Poincare diagrams). The results from the various procedures are compared for efficiency in early pinpointing of damage and reliability in the detection. Based on this study, it was found that, in the case of race damage in which interactions with the damage area take place in a periodic manner during shaft rotation, vibration signals resulting from contacts with the damage location can generally be found within a typical window of data sampling, and damage can be identified using all four selected online procedures. For the case of ball-element damage, the vibration signals are chaotic in nature due to the unpredictable rotational patterns of the ball elements. Under such conditions, interactions with the ball-element damage area may not occur within the particular data sampling period, and as a result, damage cannot be detected by the traditional time-frequency procedures. It is also demonstrated that, in this study, the modified Poincare map approach using a relatively large amount of sampling data can be effective in identifying damage in the ball rolling element.
Small-scale patterns in community structure of Sarracenia purpurea inquilines

We examined the environmental factors associated with community structure in the inquiline communities of the purple pitcher plant (Sarracenia purpurea L.). We sampled all 141 communities in a 10- x 20-m grid and recorded their spatial relationships to determine the relative influence of environmental and spatial factors on community structure. Environmental and spatial factors contributed equally to the variance in community composition (species identity and abundance) among pitchers. The species richness of communities was influenced by both spatial and environmental variables, particularly environmental variables related to community size. In addition, our study suggests a number of hypotheses about factors influencing community structure (e.g. predation) that could be tested experimentally.
Stresses in a layered rotating disk

Abstract The solution for the state of stress of a symmetrical, three-layer circular disk, rotating about its own axis, with top and bottom layers of the same material and thickness, but differing from the center substrate, to which they are rigidly bonded, is obtained in terms of Fourier-Bessel integrals. The solution applies to that for a solid rotating disk when the elastic properties of the layered materials are the same as those of the substrate. Numerical results are obtained to show the effect of the difference in the elastic properties between the layers and the substrate on the state of existing stresses and are compared with Timoshenko and Goodier's solution for the case of a solid disk.
Fundamental Combustion Properties of H2/CO Mixtures: Ignition and Flame Propagation at Elevated Pressures

Because of the current interest in the use of syngas in gas turbine applications, this article provides an overview of the fundamental combustion characteristics of H2/CO mixtures, with emphasis on ignition and flame propagation at high pressures. Specifically, the effects of pressure on the fundamental combustion properties, including auto-ignition delays, forced ignition limits, and laminar flame speeds, are demonstrated and discussed through several recent high-pressure experiments. The controlling reactions in ignition and flame propagation are identified. Through comparison of the newly obtained high-pressure experimental data and the computational results based on existing kinetic models, discrepancies in the rate parameters for the sensitive reactions are also discussed.
Barium enema findings in type I hepatorenal glycogen storage disease.

Four children with Type I hepatorenal glycogen storage have been studied by barium enema. All showed strikingly similar changes of a smooth-walled, slightly narrow but normal length colon without any haustration. The findings simulated colitis but the patients had either mild diarrhea or no gastrointestinal complaints. Small bowel series was normal. Endoscopy and biopsy failed to provide an adequate explanation, there being no evidence of glycogen storage in the biopsy material and the degree of colitis in two patients who were endoscoped was minimal. The explanation for these radiographic findings is not known at present, although they have similarities to the “cathartic colon syndrome” described in adults.
Coulomb-nuclear interference in elastic heavy-ion scattering

Abstract Elastic heavy-ion angular distributions at small angles, forward of the quarter-point angle, have often been characterized as examples of either a Coulomb rainbow or of Fresnel diffraction. Using the modern high-quality data of Hostachy et al. as an example, we argue that the truth is intermediate between these two extremes, and indeed so far from them as to make both models quite inappropriate descriptions of nuclear reality. We suggest retreating to the more general label of “Coulomb-nuclear interference”, which includes both of these (inapplicable) extremes as special cases. A semiclassical analysis of optical-model fits is found to offer helpful insight into the nature of this interference.
Governing equations for heat and mass transfer in heat-generating porous beds—II. Particulate melting and substrate penetration by dissolution

Abstract Upon dryout of the bed, the dominant modes of heat transfer are conduction and radiation. Radiation is modeled through the Rosseland approximation. The melting of stainless-steel particulate imbedded in the fuel is modeled by assuming the bed to be a continuum with conduction and radiation as the dominant modes of heat transfer. The molten steel, after it drains to the bottom of the bed, is assumed to disappear into cracks and mortar joints of the MgO bricks. The melting of fuel in the interior of the bed is modeled identically to the steel particulate, except for the bed settling which is more pronounced in the case of fuel melting and is assumed to be instantaneous owing to the significant weight of overlying bed and sodium pool. The molten layer of fuel, as it collects at the bottom of the bed, causes the heatup of the MgO lining to the eutectic temperature (2280°C), and the MgO lining begins to dissolve. The density gradient caused by the dissolution of MgO leads to natural convection and mixing in the molten layer. The submerged fuel particulate also begins to dissolve in the molten solution and ultimately leads to the conversion of debris to a molten pool of fuel and MgO. The process of penetration of the MgO lining continues until the mixing process lowers the concentration of fuel in the volume of the pool to the level where the internal heat rate per unit volume is not enough to keep the body of the pool molten and leads to freezing in the cooler part of the pool. As the molten pool reaches a frozen or a quiescent state, the MgO brick lining thickness provided is deemed ‘safe’ for a given bed loading and the external rate of cooling.
Effects of nanosecond pulsed electric fields on the human prostate cancer cell line LNCaP

The effects of nanosecond pulsed electric fields (nsPEF) on the human prostate cancer cell line LNCaP was investigated for changes in protein and DNA concentrations as well as for the 11beta hydroxysteroid dehydrogenase type 2 (11betaHSD2) enzyme activity. Electric fields with intensities of 32.5 kV/cm and pulse widths of 60 ns were applied to cancer cells in trains of 1, 5, and 10 pulses. Protein concentrations were determined through a Bio-Rad DC protein assay, while Hoechst 33258 was used to quantify DNA concentrations. The analyses showed that protein concentrations decreased by 18.77% and 19.04% for 1 and 10 pulses, respectively, while DNA concentrations decreased by 5.29%, 8.95%, and 18.36% for 1, 5, and 10 pulses, respectively, as compared to control groups. The 11betaHSD2 enzyme activity in LNCaP cells also decreased following exposure, thus supporting our initial hypothesis that ultrashort pulses affect intracellular structures; thus, a decrease in the enzyme activity could result in enhancing the anti-proliferative actions of glucocorticoids.
Ventricular function following experimental coronary artery bypass grafting: the relationship of functional improvement to haemodynamics in the graft

The effects of myocardial revascularization were studied acutely in 13 dogs with chronic coronary artery occlusion. In nine animals an improvement in ventricular function was demonstrated following revascularization. Functional improvement was generally associated with high flow through the graft and low collateral flow.
Deciduous-forest bird communities in a fragmented landscape dominated by exotic pine plantations

Impacts of habitat fragmentation on forest bird communities have often been studied in landscapes dominated by agriculture. The striking structural differences between forest fragments and the matrix have led most researchers to rely on island biogeographic theory to predict the distribution of bird species in fragmented forests. However, in some cases the vegetation surrounding fragments is not completely unsuitable for forest birds. Thus, a more general framework is needed to understand the effects of habitat fragmentation. The mosaic approach considers fragments as integrated parts of a complex landscape composed of patches of habitat of different qualities. In the coastal area of the Maule region in central Chile the remaining hualo (Nothofagus glauca) forests cover <10% of the landscape, are severely fragmented, and are imbedded in a matrix of exotic pine plantations. We compared the island and mosaic approaches as explanations for the distribution and abundance of forest birds. Variable circular plo...
Sustainability as an Organizing Principle

The history of humankind can be written in many ways, and surely one is in the artifacts of our endeavors to survive and to make things. In so doing we have dug, drilled, planted, manufactured, mined, synthesized, burned, buried, and dumped. And in so doing, we have been the recipients of enormous advantages and as well as unfortunate legacies of our development. Just as universities have encouraged archeologists and historians to develop skills to reconstruct the workings of societies based on a few fragments of pottery or obscure texts, a technological university can provide skills to construct the works of society based upon knowledge of the legacies we would like to leave. Early efforts of the technological university in the area of environmental legacies were naturally directed toward applying engineering and scientific disciplines to the challenge of characterizing and reducing risk from contaminated soils, water, and air. From the first frightening days of the modern environmental era emerged new technology for containment, for washing contaminated soil, for scrubbing contaminated air, and for removal of pollutants from water. Technological universities aided these developments by improvements and advances. These included phytoremediation, microwaves for soil cleanup, microbial remediation, pneumatic fracturing, sequential batch reactions, novel membrane applications, and treatments for sulfur oxides in air. The focus at this stage was on improving performance of the risk reduction technique while achieving economical treatment costs. Later, in parallel with the foregoing, much more attention was paid to pollution prevention. Here the focus is on substituting materials in the production processes that are much more benign and that have more benign side effects. In part, the rationale for this approach is based on the belief that it is more efficient and economical to reduce waste at the source rather than striving to control it after its release into an environmental medium. Materials used, not wasted, and energy not expended to capture substances released into the air or water are a better use of society’s time and capital. Research and new thinking in pollution prevention have ranged from improved operating practices and spill and leak control to the selection of new solvents for cleaning and maintenance and to better scheduling of production. Critical analysis of the relationships between production and environmental waste has led to the understanding that product and process modification should also be included in these approaches. The concept of ‘‘design for the environment’’ has emerged from these considerations as a vital tool for improving the quality and costs of products and protecting the quality of the environment, while extending the usable supply of raw materials and energy resources.
Dyadic Green's Functions for an Anisotropic, Non-Local Model of Biased Graphene

Dyadic Green's functions are presented for an anisotropic surface conductivity model of biased graphene. The graphene surface can be biased using either a perpendicular static electric field, or by a static magnetic field via the Hall effect. The graphene is represented by an infinitesimally-thin, two-sided, non-local anisotropic conductivity surface, and the field is obtained in terms of Sommerfeld integrals. The role of spatial dispersion is accessed, and the effect of various static bias fields on electromagnetic field behavior is examined. It is shown that by varying the bias one can exert significant control over graphene's electromagnetic propagation characteristics, including guided surface wave phenomena, which may be useful for future electronic and photonic device applications.
An Elementary Classification of Finite Metacyclic p-Groups of Class at Least Three

In this paper, we classify metacyclic p-groups of nilpotency class at least three up to isomorphism by giving a canonical presentation for each isomorphism class.
Dielectric slab-loaded resonant cavity for applications requiring enhanced field uniformity

This paper introduces and analyzes a rectangular resonant structure that provides an alternative to the multimode resonant cavity in applications requiring enhanced field uniformity. The resonant cavity contains four dielectric loading slabs placed along the cavity walls. Its first resonant mode is related to the uniform field distribution supported in a rectangular TEM waveguide. The electromagnetic fields within the cavity are described using a closed-form approach, with approximations taken to account for the presence of two of the loading slabs. Application of the boundary conditions leads to an eigenvalue formulation, which is used to determine resonant frequencies and electromagnetic field distributions within the cavity. Measurements of both resonant frequencies and electric field magnitudes confirm the analysis. This work provides the basis for future analyses and implementation of slab-loaded cavities in both scientific and industrial settings.