cssi/SciSciGPT-SciSciNet huggingface dataset:
Quantum cluster size and solvent polarity effects on the geometries and Mössbauer properties of the active site model for ribonucleotide reductase intermediate X: a density functional theory study

In studying the properties of metalloproteins using ab initio quantum mechanical methods, one has to focus on the calculations on the active site. The bulk protein and solvent environment is often neglected, or is treated as a continuum dielectric medium with a certain dielectric constant. The size of the quantum cluster of the active site chosen for calculations can vary by including only the first-shell ligands which are directly bound to the metal centers, or including also the second-shell residues which are adjacent to and normally have H-bonding interactions with the first-shell ligands, or by including also further hydrogen bonding residues. It is not well understood how the size of the quantum cluster and the value of the dielectric constant chosen for the calculations will influence the calculated properties. In this paper, we have studied three models (A, B, and C) of different sizes for the active site of the ribonucleotide reductase intermediate X, using density functional theory (DFT) OPBE functional with broken-symmetry methodology. Each model is studied in gas-phase and in the conductor-like screening (COSMO) solvation model with different dielectric constants e = 4, 10, 20, and 80, respectively. All the calculated Fe-ligand geometries, Heisenberg J coupling constants, and the Mossbauer isomer shifts, quadrupole splittings, and the 57Fe, 1H, and 17O hyperfine tensors are compared. We find that the calculated isomer shifts are very stable. They are virtually unchanged with respect to the size of the cluster and the dielectric constant of the environment. On the other hand, certain Fe-ligand distances are sensitive to both the size of the cluster and the value of e. e = 4, which is normally used for the protein environment, appears too small when studying the diiron active site geometry with only the first-shell ligands as seen by comparisons with larger models.
Conformational properties of the A-state of cytochrome c studied by hydrogen/deuterium exchange and electrospray mass spectrometry

Abstract Hydrogen/deuterium (H/D) exchange studies that were monitored by liquid chromatography–electrospray ionization mass spectrometry (LC–ESIMS) were used to obtain a structural description of the compact acid-denatured state of ferricytochrome c (A-state). Due to the very different solvent conditions necessary to generate the nonnative states, it was essential that after deuterium labeling the nonnative states were refolded to the native state to insure high reproducibility during sample preparation and LC–ESIMS analysis. Approximately 30% lower deuterium was found incorporated in the A-state compared to the acid-denatured (U A ) state. The analysis of the width of the mass peak suggests that the distribution of conformers sampled in the A-state was relatively narrow and that the compactness of the A-state was much closer to that of the native state than to the acid-denatured state. The LC–ESIMS study of partially deuterium-labeled peptic fragments derived from the A-state conformer generated under H/D quenching conditions were interpreted in terms of a significant loss of structural integrity within amino acid region 22–46.
REGULATION OF ORGANELLE TRANSPORT : LESSONS FROM COLOR CHANGE IN FISH

Organelles transported along microtubules are normally moved to precise locations within cells. For example, synaptic vesiceles are transported to the neruronal synapse, the Golgi apparatus is generally found in a perinuclear location, and the membranes of the endoplasmic reticulum are actively extended to the cell periphery. The correct positioning of these organelles depends on microtubules and microtubule motors. Melanophores provide an extreme example of organized organelle transport. These cells are specialized to transport pigment granules, which are coordinately moved towards or away from the cell center, and result in the cell appearing alternately light or dark. Melanophores have proved to be an ideal system for studying the mechanisms by which the cell controls the direction of its organelle transport. Pigment granule dispersion (the movement away from the cell center) requires protein phosphorylation, while pigment aggregation (the movement towards the cell center) requires protein dephosphorylation. The target of this phosphorylation and dephosphorylation event is a protein that interacts with the microtubule motor protein, kinesin. Thus, the direction of organelle transport along microtubules may be regulated by controlling the activity of a microtubule motor.
The Bacteriology of Brick Cheese. III. The Bacteria Involved in Ripening

Summary Examination of 1016 cultures isolated at different stages of ripening from 18 lots of Brick cheese yielded the following results: 1Str. lactis was the predominant organism throughout the ripening of cheese in which it was used as part or all of the starter. Its numbers rose steadily to one to three billions per gram during the first one to four days, and declined again after three to four weeks. It also increased slowly in cheese to which it had not been added and reached numbers of several hundred millions per gram after one to two weeks. 2When Str. thermophilus was used as the starter its numbers increased rapidly to a maximum of one to two billions per gram at twelve hours, then after one to two weeks they decreased sharply and the organisms seldom were found later in the ripening period. 3Lactobacilli were found in the raw milk cheese after the first one or two weeks, but they seldom appeared in cheese made from pasteurized milk. L. casei occurred most frequently and in numbers up to ten to one hundred millions per gram; L. brevis was found less consistently than L. casei and usually in much smaller numbers; L. lactis appeared in a few of the samples after three to four weeks in insignificant numbers. 4Str. liquefaciens was found in six of the lots of cheese after two to three weeks in numbers sometimes as high as 10,000,000 per gram. A few instances of bitter flavor probably were due to excessive numbers of this organism. 5Str. bovis and Str. fecalis usually appeared in the cheese after one to two weeks, and ranged in numbers from a few thousands to as high as one hundred millions per gram. These organisms were most prevalent in cheese made from pasteurized milk. 6Late gas formation by anaerobic spore forming bacteria occurred in all cheese in which the pH did not drop below 5.3 during the first three days of ripening. This condition was most pronounced in cheese made with Str.thermophilus starter by the washed-curd method from pasteurized milk. The main function of the starter bacteria is a rapid and steady production of lactic acid during manufacture. The most important organism in bringing about the changes in body within the cheese during ripening is L. casei, and this organism also contributes to the flavor.
Laetoli Footprints Preserve Earliest Direct Evidence of Human-Like Bipedal Biomechanics

Background Debates over the evolution of hominin bipedalism, a defining human characteristic, revolve around whether early bipeds walked more like humans, with energetically efficient extended hind limbs, or more like apes with flexed hind limbs. The 3.6 million year old hominin footprints at Laetoli, Tanzania represent the earliest direct evidence of hominin bipedalism. Determining the kinematics of Laetoli hominins will allow us to understand whether selection acted to decrease energy costs of bipedalism by 3.6 Ma.
Trace metal enrichments in Lake Tanganyika sediments: Controls on trace metal burial in lacustrine systems

Abstract We investigate the distributions of several key diagenetic reactants (C, S, Fe) and redox-sensitive trace metals (Mo, Cd, Re, U) in sediments from Lake Tanganyika, East Africa. This study includes modern sediments from a chemocline transect, which spans oxygenated shallow waters to sulfidic conditions at depth, as well as ancient sediments from a longer core (∼2 m) taken at ∼900 m water depth. Modern sediments from depths spanning ∼70–335 m are generally characterized by increasing enrichments of C, S, Mo, Cd, and U with increasing water depth but static Fe distributions. It appears that the sedimentary enrichments of these elements are, to varying degrees, influenced by a combination of organic carbon cycling and sulfur cycling. These modern lake characteristics contrast with a period of high total organic carbon (Corg), total sulfur (STot), and trace metal concentrations observed in the 900 m core, a period which follows the most recent deglaciation (∼18–11 ky). This interval is followed abruptly by an interval (∼11–6 ky) that is characterized by lower C, S, U, and Mo. Consistent with other work we suspect that the low concentrations of S, Mo, and U may indicate a period of intense lake mixing, during which time the lake may have been less productive and less reducing as compared to the present. An alternative, but not mutually exclusive, hypothesis is that changes in the lake’s chemical inventory, driven by significant hydrological changes, could be influencing the distribution of sedimentary trace elements through time.
The effects of cycloheximide on the ultrastructure of rat liver cells

Abstract Within 6 h after the administration of cycloheximide, perichromatin granules in the rat liver nucleus were significantly increased in number and concentration. In the cytoplasm, glycogen loss and degranulation of the endoplasmic reticulum were observed. In addition, numerous membranous whorls and lamellar structures were distributed throughout the cytoplasm. These observations suggest a close association between the inhibition to cytoplasmic protein synthesis and the biosynthesis of perichromatin granules.
Intranuclear distribution of satellite DNA from kangaroo rat.

Abstract Nuclei, nucleoli and three chromatin fractions of varying density were prepared from the livers of kangaroo rats, which have an unusually large content of two satellite DNAs. These components were incubated with sodium dodecyl sulfate and Pronase and were submitted to analytical buoyant density ultracentrifugation in CsCl gradients. The nucleoli and heavy chromatin fractions were markedly enriched in the satellite DNAs. The distribution was similar to that previously reported in the laboratory mouse; however, in the kangaroo rat about 48% of the total cell DNA was present as satellites.
An Unusual Cause of Hoarseness: Rhabdomyosarcoma of the Larynx

Laryngeal sarcomas account for <1% of laryngeal malignancies. Laryngeal spindle cell rhabdomyosarcomas (RMS) are rare with only a few reports in the literature. Presenting symptoms vary from hoarseness or dysphagia to respiratory failure. Four subdivisions of rhabdomyosarcomas exist including embryonal, alveolar, pleomorphic, and botryoid variant. Worse outcomes have been found in adults versus children. Multimodality therapy remains the mainstay of treatment. Our report describes a case of a 30 year old man with hoarseness discovered to have glottic spindle cell rhabdomyosarcoma. He underwent frontolateral partial laryngectomy followed by chemotherapy and radiation.
Effect of salt stress on plant gene expression: A review

Soil salinity is an important agricultural problem, particularly since the majority of crop plants have low salt tolerance. The identification of genes whose expression enables plants to adapt to or tolerate salt stress is essential for breeding programs, but little is known about the genetic mechanisms for salt tolerance. Recent research demonstrates that salt stress modulates the levels of a number of gene products. Although the detection of gene products that respons specifically to salt stress is a significant finding, they must be identified, functions assigned, and their relation to salt tolerance determined. This article focuses on a few of the salt-responsive proteins and mRNAs that have been discovered and the methods employed to identify and characterize them.
A quantum memory with telecom-wavelength conversion

Atomic transitions afford a convenient way of storing quantum bits. However, there are few ground-state transitions suitable for use with light at telecommunication wavelengths. Now, researchers show that ensembles of cold rubidium atoms not only make good quantum memories, but can also noiselessly convert the emitted photons into and out of the telecoms band.
Independent Component Analysis by Using Joint Cumulants and its Application to Remote Sensing Images

In this paper, a joint cumulant independent component analysis (JC-ICA) algorithm is presented. It utilizes the higher order joint cumulants to extract independent components and can be implemented efficiently by a neural network. Its application in SAR (synthetic aperture radar) image analysis is presented and a comparison is also made with two other ICA methods. The results show the usage in image analysis and separation. Because the algorithm is based on statistics of order higher than the second, it is suitable also for applications to data with non-Gaussian distributions in blind signal processing.
Contribution of Helicobacter hepaticus cytolethal distending toxin subunits to human epithelial cell cycle arrest and apoptotic death in vitro.

Background Cytolethal distending toxin (CDT) is the only known virulence factor found in H. hepaticus, the cause of chronic typhlocolitis and hepatitis leading to colonic and hepatocellular carcinomas in mice. Interaction of the tripartite polypeptide CdtA, CdtB, and CdtC subunits produced by H. hepaticus CDT (HhepCDT) causes cell cycle arrest and apoptotic death of cultured cells; however, the contribution of individual subunit to these processes has not been investigated. Materials and Methods The temporal relationship between cell cycle and apoptotic death of human epithelial HeLa and INT407 cells intoxicated with HhepCDT holotoxin or reconstituted recombinant HhepCDT was compared by flow cytometry. The genotoxic activity of individual and combinations of recombinant HhepCDT protein subunits or increasing concentrations of individual recombinant HhepCDT protein subunits transfected into HeLa cells was assessed at 72 hours post-treatment by flow cytometry. Results Similar time course of HhepCDT-induced G2/M cell cycle arrest and apoptotic death was found with both cell lines which reached a maximum at 72 hours. The presence of all three HhepCDT subunits was required for maximum cell cycle arrest and apoptosis of both cell lines. Transfection of HeLa cells with HhepCdtB, but not with HhepCdtA or HhepCdtC, resulted in a dose-dependent G2/M arrest and apoptotic death. Conclusion All three subunits of HhepCDT are required for maximum epithelial cell cycle arrest and progression to apoptotic death, and HhepCdtB subunit alone is necessary and sufficient for epithelial cell genotoxicity.
The Influence of Body Dissatisfaction on Set Shifting Ability

Set shifting, or the ability to shift back and forth between multiple tasks or mental sets, has been shown to be impaired in individuals with eating disorders. The purpose of this study was to experimentally examine set shifting among acutely body dissatisfied women. Participants included 146 undergraduate women selected for self-reported high or low body shame. Each participant was randomized to one of three still-image induction groups: body dissatisfaction, negative affect, or neutral affect. Immediately following the induction, participants were administered the Wisconsin Card Sorting Test (WCST) to assess set shifting. A 2 (high vs. low body shame) × 3 (induction group condition) ANOVA was conducted on the total number of WCST perseverative errors. The results suggest that for women who feel relatively satisfied with their bodies, thin ideal or negative affective images do not impact set shifting performance. However, for women who experience body shame, acute body dissatisfaction and negative affect may impact executive functioning as demonstrated by set shifting performance. In other words, women who endorse body shame may have difficulty shifting set during moments of increased negative affect, regardless of the general or body-specific nature of the negative affect.
Cyclic 3',5'-AMP and uterine contractility.

Hays and Vandemark1 observed decreased spontaneous motility of the bovine uterus after administration of adrenaline and partial or complete inhibition of the uterine response to oxytocin. Jensen and Vennerod2 reported inhibition of the uterine contraction to human urinary kinin after adrenaline. In neither case was the mechanism of this induced inhibition explained. Our experiments offer a possible explanation of this phenomenon and point out its physiological significance.
Lymphoblastoid transmembrane potential in bipolar patients, their siblings, and unrelated healthy comparison subjects

Abstract Bipolar illness appears to be characterized by alterations in ionic homeostasis that are related to mood state. This is reflected by reports of altered intracellular sodium and calcium concentrations, altered sodium pump (Na + ,K + -adenosine triphosphatase), and calcium pump (Ca 2+ -adenosine triphosphatase) activity. Recent ex vivo studies with fresh lymphocytes and in vitro studies with cultured lymphoblasts suggest that there may be an enduring trait-related abnormality in Na + ,K + -adenosine triphosphatase as well. We have previously found that the lymphocyte transmembrane potential (TMP) varies with mood state. To examine the question of trait-related changes in TMP, we studied TMP of immortalized lymphoblasts from 14 patients with bipolar illness, nine unaffected siblings, and eight normal subjects. TMP was the same in all three groups. These preliminary data suggest that TMP is a state- rather than a trait-related marker.
A facile synthesis of ceramides.

Abstract A new simple procedure for the synthesis of ceramide from free fatty acid and sphingosine by oxidation-reduction condensation with triphenylphosphine and 2,2′-dipyridyldisulfide has been described. N-lignoceroyl and N-cerebronoyl sphingosine were synthesized with this procedure producing an overall yield of 74% from lignoceric acid and 64% from cerebronic acid.
Minimal 10D anomaly-free supergravity and the effective superstring theory

Abstract Using a theorem by Bonora, Pasti and Tonin on the existence of a solution for D =11, N =1 Bianchi identities in the presence of the Lorentz-Chern-Simons form we found the explicit rheonomic parametrizations of all curvatures. This leads to a differential equation for the torsion field which we exhibit and also to the equations of motion whose form has not been worked out yet. We show how the lagrangian can be constructed and we argue that the presently constructed anomaly free supergravity contains all the terms of the heterotic string effective theory except those with a ζ(3) coefficient whose addition ought to be studied.
Viral Protein Synthesis in Bacteriophage φ29-Infected Bacillus subtilis

Abstract Twenty-three 14C-labeled phage 29-specific proteins in lysates of UV-irradiated Bacillus subtilis have been resolved by sodium dodecyl sulfate polyacrylamide gel electrophoresis and identified by autoradiography. Included in this group of proteins are the six major structural proteins of the virion. Analysis of the temporal sequence of viral protein synthesis indicates that three groups of proteins can be identified by time of appearance, beginning at 2 to 4, 4 to 6, or 8 to 10 min after infection, respectively. These proteins account for approximately 90% of the coding capacity of the 29 genome.
The reaction of formaldehyde with denatured DNA: Spectrophotometric, immunologic, and enzymic studies

The reaction between formaldehyde and thermally denatured DNA has been studied by spectrophotometric, immunologic, and enzymatic methods. Formaldehyde reacts with amino groups which become available during thermal denaturation of DNA, and the formaldehyde-linked amino groups are no longer available for hydrogen bonding on cooling of the denatured DNA. Renaturation during slow cooling is prevented by formaldehyde, as is random intramolecular hydrogen bonding during rapid cooling. Formaldehyde increases the antigenic effectiveness of rapidly cooled denatured DNA in complement fixation reactions with natural and experimental antibodies to denatured DNA. This effect is interpreted as reflecting the role of formaldehyde in preventing the intramolecular hydrogen bonding, and thus maintaining the molecule in a relatively uncoiled state, more efficient for antigen—antibody aggregation. Hydrolysis of heat denatured DNA by an exonucleolytic phosphodiesterase of E. coli B proceeds at 35°C at a rapid initial rate, followed by a second slower rate. At 45°C, the reaction follows a single rate to completion. DNA denatured in the presence of formaldehyde is acted upon at 35°C at a similar single rate. It is concluded that the effect of formaldehyde, and of the increased temperature, is to produce a less hydrogen-bonded molecule, all parts of which are readily accessible to the enzyme. These experimental results are consistent with the hypothesis that rapidly cooled denatured DNA exists as a randomly coiled structure, containing intramolecular hydrogen bonds involving the amino groups of the purine and pyrimidine bases.
Measurement of 15N relaxation rates in perdeuterated proteins by TROSY-based methods

While extracting dynamics parameters from backbone 15N relaxation measurements in proteins has become routine over the past two decades, it is increasingly recognized that accurate quantitative analysis can remain limited by the potential presence of systematic errors associated with the measurement of 15N R1 and R2 or R1ρ relaxation rates as well as heteronuclear 15N-{1H} NOE values. We show that systematic errors in such measurements can be far larger than the statistical error derived from either the observed signal-to-noise ratio, or from the reproducibility of the measurement. Unless special precautions are taken, the problem of systematic errors is shown to be particularly acute in perdeuterated systems, and even more so when TROSY instead of HSQC elements are used to read out the 15N magnetization through the NMR-sensitive 1H nucleus. A discussion of the most common sources of systematic errors is presented, as well as TROSY-based pulse schemes that appear free of systematic errors to the level of <1 %. Application to the small perdeuterated protein GB3, which yields exceptionally high S/N and therefore is an ideal test molecule for detection of systematic errors, yields relaxation rates that show considerably less residue by residue variation than previous measurements. Measured R2′/R1′ ratios fit an axially symmetric diffusion tensor with a Pearson’s correlation coefficient of 0.97, comparable to fits obtained for backbone amide RDCs to the Saupe matrix.
Outline extraction of microfossils in reflected light images

Abstract Microcomputer-based systems coupled with real-time video digitizers provide an efficient method of collecting shape data by extracting the outline of an object presented for viewing from a digitized video image. A system is described for outline extraction of microfossil specimens viewed in reflected light, focusing on software algorithms which are appropriate for the anticipated images. Implemented procedures draw heavily on standard techniques such as image segmentation based on thresholding, and edge extraction utilizing the method of heuristic search. The approach makes several assumptions about the images which limits its general applicability. However, it is considered readily adaptable to other images, such as those produced by a scanning-electron microscope, which have similar properties to those observed using reflected light, and which might be encountered by workers studying shape.
Wrist position affects loading of the dorsal scaphoid: possible effect on extrinsic scaphoid blood flow.

Cadaver studies using radial artery injection techniques were used to study the vascular supply along the dorsal ridge of the scaphoid. These revealed an intraarticular membrane between the wrist capsule and the dorsal ridge of the scaphoid through which arteriolar vessels (25–100 μm internal diameter) passed. Biomechanical tests revealed that the extensor carpi radialis brevis may apply significant pressure to the dorsal ridge of the scaphoid when the wrist is flexed. The highest pressures occurred with the wrist flexed at 60° or 90° and in slight (15°) ulnar deviation. The authors suggest that these vascular and biomechanical factors may contribute to the aetiology for idiopathic osteonecrosis of the scaphoid.
Further notes on Mesolithic-Neolithic contacts in the Iron Gates Region and the Central Balkans

Hunter-gatherer/farmer contact in the Iron Gates region is re-examined in view of recent archaeological research, and the social dynamics, population movements and interactions of small scale societies. Full, non-hostile interaction between hunter-gatherers and farmers in the Iron Gates region is proposed for the mid- 7th millennium calBC, followed by hunter-gatherer encapsulation at the end 7th millennium calBC. The lack of archaeological records on the Central Balkan Postglacial and Early Holocene hunter-gatherers is highlighted as a major obstacle to fully understanding cultural transformations, including the Neolithic transition, in this region.
Chandra data archive operations

The Chandra Data Archive plays a central role in the Chandra X-ray Center (CXC) that manages the operations of the Chandra X-ray Observatory. We shall give an overview of two salient aspects of the CDA's operations, as they are pertinent to the operation of any large observatory. First, in the database design it was decided to have a single observation catalog database that controls the entire life cycle of Chandra observations (as opposed to separate databases for uplink and downlink, as is common for many scientific space missions). We will discuss the pros and cons of this design choice and present some lessons learnt. Second, we shall review the complicated network that consists of Automated (pipeline) Processing, archive ingest, Verification & Validation, reprocessing, data distribution, and public release of observations. The CXC is required to deliver high-level products to its users. This is achieved through a sophisticated system of processing pipelines. However, occasional failures as well as the need to reprocess observations complicate this seemingly simple series of actions. In addition, we need to keep track of allotted and used observing time and of proprietary periods. Central to the solution is the Processing Status Database which is described in more detail in a related poster presentation.
Kilovoltage Rotational External Beam Radiotherapy on a Breast Computed Tomography Platform: A Feasibility Study

Purpose To demonstrate the feasibility of a dedicated breast computed tomography (bCT) platform to deliver rotational kilovoltage (kV) external beam radiotherapy (RT) for partial breast irradiation, whole breast irradiation, and dose painting. Methods and Materials Rotational kV-external beam RT using the geometry of a prototype bCT platform was evaluated using a Monte Carlo simulator. A point source emitting 178 keV photons (approximating a 320-kVp spectrum with 4-mm copper filtration) was rotated around a 14-cm voxelized polyethylene disk (0.1 cm tall) or cylinder (9 cm tall) to simulate primary and primary plus scattered photon interactions, respectively. Simulations were also performed using voxelized bCT patient images. Beam collimation was varied in the x–y plane (1–14 cm) and in the z-direction (0.1–10 cm). Dose painting for multiple foci, line, and ring distributions was demonstrated using multiple rotations with varying beam collimation. Simulations using the scanner's native hardware (120 kVp filtered by 0.2-mm copper) were validated experimentally. Results As the x–y collimator was narrowed, the two-dimensional dose profiles shifted from a cupped profile with a high edge dose to an increasingly peaked central dose distribution with a sharp dose falloff. Using a 1-cm beam, the cylinder edge dose was i.e. , skin sparing) was demonstrated by weighted summation of four dose profiles using different collimation widths. Simulations using patient bCT images demonstrated the potential for treatment planning and image-guided RT. Conclusions Rotational kV-external beam RT for partial breast irradiation, dose painting, and whole breast irradiation with skin sparing is feasible on a bCT platform with the potential for high-resolution image-guided RT.
Superconducting loop quantum gravity and the cosmological constant

We argue that the cosmological constant is exponentially suppressed in a candidate ground state of loop quantum gravity as a nonperturbative effect of a holographic Fermi-liquid theory living on a two-dimensional spacetime. Ashtekar connection components, corresponding to degenerate gravitational configurations breaking large gauge invariance and CP symmetry, behave as composite fermions that condense as in Bardeen–Cooper–Schrieffer theory of superconductivity. Cooper pairs admit a description as wormholes on a de Sitter boundary.
Insect and fungal chitin synthetase activity: specificity of lectins as enhancers and nucleoside peptides as inhibitors.

Abstract Tribolium castaneum chitin synthetase (CS) activity is stimulated by chitooligosaccharide-binding lectins by up to 2.5-fold in the presence of N -acetyl- d -glucosamine (GlcNAc) and up to 3.5-fold in the absence of GlcNAc. Lectins of particularly high stimulating activity are those obtained from Triticum vulgaris and Phytolacca americana , but not those derived from eight other species with no specificity for GlcNAc. T. castaneum CS is inhibited 50% by 0.2 μ M nikkomycin Z (NZ) and the inhibitory effect is not alleviated by stimulating lectins. The CS of Neurospora crassa differs from that of T. castaneum by its lower sensitivity to inhibition by NZ and lesser stimulatory effects of lectins. Apparently the lectins do not act at the active site of Tribolum CS but may instead facilitate the detachment of GlcNAc polymers, thereby enhancing incorporation of label from uridine 5′-diphospho-[ 3 H]GlcNAc.
The electron microscopy of F-actin

Abstract Electron micrographs have been made of deposits of F-actin polymerized in situ from the globulin form. Aggregates of fibers obtained in this way show a new cross segmentation and lateral association which indicates a fine structure within the single fibers.
Local energy as an indicator of the accuracy of wave functions and probability densities for helium

The local energy is examined as an indicator of the accuracy of approximate wave functions for the ground state of helium. It is observed that at a given point (1) an inaccurate local energy may or may not correspond to an inaccurate value of the wave function or probability density, but (2) a value of the local energy within 0.1 a.u. of the ground-state energy corresponds to a value of the approximate wave function or probability density within about 10% of that for the ground-state wave function.
Poor correlation between the erythrocyte sedimentation rate and clinical activity in juvenile rheumatoid arthritis.

Despite questions regarding its validity as an estimator of inflammatory disease activity, monitoring of the erythrocyte sedimentation rate (ESR) continues to be routine practice among pediatric rheumatologists caring for children with juvenile rheumatoid arthritis (JRA). We studied a large group of patients with JRA in order to determine the degree of correlation between clinically apparent inflammation and the ESR. regression and correlation analyses and descriptive statistical techniques were used to establish the relationship between 1) the ESR and the amount of clinically apparent inflammation at a point in time, and 2) changes in the ESR and the corresponding changes in apparent inflammation. One hundred fifty-nine children with JRA who were participants in a double-blind, controlled trial of two antirheumatic drugs were assessed for clinical and laboratory evidence of inflammatory disease activity at an initial visit, and then periodically for the duration of the one year study. Results showed that, at the initial assessment, neither the total number of joints with active arthritis nor the severity score correlated well with the ESR (r=.196 and .245 respectively). These findings were independent of the course type of JRA and age of the child. Changes from baseline in inflammation showed little correlation (r<.25) with changes in the ESR. These findings suggest that the ESR is a relatively poor indicator of the amount of articular inflammation present, and that changes of disease activity are not reflected closely by changes in the ESR among children with JRA.
Some observations on the carbon dioxide burst in chlorella and chlamydomonas.

In the course of mass spectrometer studies with the algae Chlorella and Chlamydomonas, data were obtained which indicate that the CO(2) burst and gulp are sensitive to oxygen. Furthermore, the CO(2) burst was found to be strongly suppressed when wave lengths shorter than 460 nanometers were blocked at intensities adequate to saturate photosynthesis. Under appropriate conditions at 30 degrees , the CO(2) burst was interrupted by a brief CO(2) gulp and the post illumination gulp by a brief burst of CO(2). The post illumination gulp of CO(2) could be induced during illumination by interposition of a filter blocking wave lengths shorter than 460 nanometers. These data are discussed in relation to earlier reports of the phenomenon and briefly as they affect the detection of photorespiration.
How long is a moment: The perception and reality of task-related absences

We have investigated actual and perceived human performance associated with a simple task involving walking and applied the developed knowledge to a human-robot interaction. Based on experiments involving walking at a “purposeful and comfortable” pace, parameters were determined for a trapezoidal model of walking: starting from standing still, accelerating to a constant pace, walking at a constant pace, and decelerating to a stop. We also collected data on humans’ evaluation of the accomplishment of a simple task involving walking: determining the transitions from having taken too short a period of time to an appropriate time and from having taken an appropriate time to having taken too long. People were found to be accurate in estimating the task duration for short tasks, but to underestimate the duration of longer tasks. This information was applied to a human-robot interaction involving a human leaving for a “moment” and the robot knows how long the task should take and how time is evaluated by a human.
Document similarity based on concept tree distance

The Web is quickly moving from the era of search engines to the era of discovery engines. Whereas search engines help you find information you are looking for, discovery engines help you find things that you never knew existed. A common discovery technique is to automatically identify and display objects similar to ones previously viewed by the user. Core to this approach is an accurate method to identify similar documents. In this paper, we present a new approach to identifying similar documents based on a conceptual tree-similarity measure. We represent each document as a concept tree using the concept associations obtained from a classifier. Then, we make employ a tree-similarity measure based on a tree edit distance to compute similarities between concept trees. Experiments on documents from the CiteSeer collection showed that our algorithm performed significantly better than document similarity based on the traditional vector space model.
Aspects of The Optimization Process in Practice

Occasionally, a structural analyst will write a design program that includes the calculation of structural response as well as an implementation of a constrained optimization algorithm, such as those discussed in Chapter 5. More often the analyst will have a structural analysis package, such as a finite-element program, as well as an optimization software package available to him. The task of the analyst is to combine the two so as to bring them to bear on the structural design problem that he wishes to solve.
An Inquiry into Protein Structure and Genetic Disease: Introducing Undergraduates to Bioinformatics in a Large Introductory Course

This inquiry-based lab is designed around genetic diseases with a focus on protein structure and function. To allow students to work on their own investigatory projects, 10 projects on 10 different proteins were developed. Students are grouped in sections of 20 and work in pairs on each of the projects. To begin their investigation, students are given a cDNA sequence that translates into a human protein with a single mutation. Each case results in a genetic disease that has been studied and recorded in the Online Mendelian Inheritance in Man (OMIM) database. Students use bioinformatics tools to investigate their proteins and form a hypothesis for the effect of the mutation on protein function. They are also asked to predict the impact of the mutation on human physiology and present their findings in the form of an oral report. Over five laboratory sessions, students use tools on the National Center for Biotechnology Information (NCBI) Web site (BLAST, LocusLink, OMIM, GenBank, and PubMed) as well as ExPasy, Protein Data Bank, ClustalW, the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, and the structure-viewing program DeepView. Assessment results showed that students gained an understanding of the Web-based databases and tools and enjoyed the investigatory nature of the lab.
War, Trade, and the Mediation of Systemic Leadership

Processes of war, trade, and systemic leadership are often examined in isolation from one another. Sometimes, two of the three are studied together. Does war interrupt trade? Does systemic leadership reduce the level of warfare? Does systemic leadership lead to freer trade? While these are familiar questions, our contention is that all three processes are interrelated at the systemic level. War and trade are dependent upon systemic leadership. Trade expands in the presence of systemic leadership, and war expands as systemic leadership declines. Yet the expansion of war is also critical to the emergence of systemic leadership. At the same time, these relationships have not remained constant over time but have evolved. The scope of systemic leadership and the intensity of war have increased while the frequency of war among the most powerful actors has contracted. Trade, on the other hand, has expanded dramatically. A vector autoregression analysis of the three processes provides substantial empirical support for the argument that leadership leads to more trade and less war, while also promoting increasingly more pacific relations among elite states in the world system.
Structural insights from high-resolution diffusion tensor imaging and tractography of the isolated rat hippocampus.

Abstract The hippocampus is a critical structure for learning and memory formation injured by diverse neuropathologies such as epilepsy or Alzheimer's disease. Recently, clinical investigations have attempted to use diffusion tensor MRI as a more specific surrogate marker for hippocampal damage. To first better understand the tissue architecture of healthy hippocampal regions, this study characterized 10 rat hippocampi with diffusion tensor imaging (DTI) at 50-μm in-plane image resolution using a 14.1-T magnet. Chemical fixation of the dissected and straightened rat hippocampus provided a simple, effective way to reduce partial volume effects when segmenting hippocampal regions and improved mean signal-to-noise per unit time (e.g. 50.6 ± 4.4 at b = 1250 s/mm2 in 27 min). Contrary to previous reports that water diffusion is homogeneous throughout the nervous system, statistically different mean diffusivities were observed (e.g. 0.238 ± 0.054 and 0.318 ± 0.084 μm2/ms for the molecular and granule cell layers respectively) (ANOVA, P
Modified SIS epidemic model for analysis of virus spread in wireless sensor networks

In this paper, a modified SIS epidemic model is proposed to study the dynamics of virus spread in wireless sensor networks. The sensor nodes are attacked by viruses and initially only a small number of nodes are infected. The virus spreads itself to its neighbour nodes by piggybacking on normal data via regular communications. The infected neighbour nodes repeat the process to their respective neighbour nodes. Each sensor node is installed with an antivirus program, which can be periodically refreshed to recover the infective nodes to the susceptible group. Some explicit solutions are derived, which can capture both the spatial and temporal dynamics of the virus spread process. An adjustable virus spread control scheme is developed to effectively restrain the virus outbreak and avoid the network failure. Numerical results and simulations are provided for validation. The proposed model and analysis method can be applied to different types of networks such as wireless networks, computer networks, biomedical networks and social networks.
Hormone-Induced Synthesis of DNA by Mammary Gland in Vitro

The hormonal requirements for stimulation of DNA synthesis in mouse mammary explants were further studied. Addition of insulin or growth hormone to the synthetic medium augmented the rate at which epithelial cells initiated DNA synthesis, but did not alter the rate of DNA replication. DNA synthesis increased linearly over a wide range of growth hormone concentrations, with a minimal effective concentration of approximately 4 × 10−9m. Although insulin induced larger numbers of epithelial cells to initiate DNA synthesis, its minimal effective concentration was higher, at approximately 4×10−8m (0.1 μg/ml). Experiments with inhibitors of protein synthesis indicated that concurrent protein synthesis is necessary for the initiation of DNA synthesis and for completion of DNA replication in these cells. (Endocrinology 82: 540, 1968)
Familial Microdeletion of 17q24.3 Upstream of SOX9 Is Associated With Isolated Pierre Robin Sequence Due to Position Effect

Pierre Robin sequence (PRS) is a malformation pattern characterized by the core triad of retrognathia, glossoptosis, and cleft palate that causes difficulty in glossopharyngeal-laryngeal-vagal functions. The etiology of PRS remains largely unknown; previous reports have suggested that it is caused by intrauterine constriction or external conditions such as oligohydramnios, breech position, or abnormal uterine anatomy. Genetic causes include occurrence as a manifestation of many single gene conditions and chromosomal rearrangements. Positional effect on some loci or genes, including SOX9 has also been posited as a cause. Here, we report on an 18-month-old girl born with isolated PRS. Clinical chromosome microarray analysis (CMA) revealed a maternally inherited ~623 kb microdeletion that is -725 kb upstream of 5' SOX9 at chromosome locus 17q24.3. Her mother had cleft palate. This region, although devoid of any genes, is known to have a position effect on SOX9 due to elimination of highly conserved non-coding cis-regulatory elements. This report supports the evidence that deregulation of an intact SOX9 coding region is a cause of or associated with isolated PRS, and provides further evidence that CMA in the clinical setting is a powerful tool in detecting microdeletions in gene "desert" regions that have pathogenic position effect on specific genes.
Probabilistic crack growth behavior of aluminum 2024-T351 alloy using the ‘unified’ approach

Abstract In a previous paper, a deterministic experimental crack growth model for aluminum 2024-T351 alloy was formulated based on published experimental results, using the ‘unified’ approach. In the present paper, random equivalent initial flaw size (EIFS) values obtained from other experimental results are introduced to the model, and the crack growth probabilistic behavior is demonstrated. The EIFS values computed from published experimental results of 3-D cracked fastener holes are well-approximated by a Weibull distribution. This approximated EIFS distribution is used as a distribution of the initial cracks in a large number of computations for a 2-D case which is very similar to the 3-D one, and serves for demonstration purposes. A computation program was written to numerically solve the behavior of crack lengths vs. the number of load cycles. It is shown that part of the initial cracks do not propagate, as their initial value is smaller than the required threshold criteria set by the ‘unified’ approach. A dispersion in the number of load cycles required to obtain a given crack length is shown. Although the coefficient of variation (COV) of this dispersion is smaller than the COV of the initial random cracks, it may be of concern to designers, as the life period of the design may change by a factor of more than 3.
Movements of male sockeye salmon, Oncorhynchus nerka, on spawning grounds: effects of in-stream residency, density and body size

Philopatry or homing isolates breeding groups and therefore strongly affects population structure within a species. In salmonid fish, the movements of males among nesting females may control gene flow, and therefore affect fine-scale population structure, within and among breeding grounds. In this study, we recorded the daily movements of male sockeye salmon from three populations during the breeding period. We modelled daily movement using an exponential function and then added additional parameters to explore the extent to which movement varied between streams, between years within streams as salmon density varied, and between males of different ages/sizes. This approach revealed that: (1) in all three streams, male movement decreased as a function of time on the breeding grounds and was limited in most cases, (2) movement patterns, particularly initial exploratory movement, differed between streams, (3) movement patterns differed between years within a stream but were unrelated to density, and (4) there was little effect of age/size on movement; the small observed effect was due to differences in exploratory movement, not sustained differences over the entire breeding season. Overall, the restricted movements by males on the breeding grounds indicated that salmon populations can be structured on fine spatial scales as a result of limited gene flow within seasons if homing to precise natal locations also occurs.
Femoral neck fractures in the elderly: A changing paradigm

Abstract Femoral neck fractures are often life-changing events, and maximizing the patient's post-injury outcome hinges on optimal surgical management. The goal is to minimize pain and disability, and restore as much as possible of the patient's pre-injury functional capacity, with a single procedure. It is helpful to approach the surgical management of femoral neck fractures with an algorithm. A decision must first be made between internal fixation and arthroplasty; internal fixation is usually chosen for younger patients or for nondisplaced femoral neck fractures at any age, while arthroplasty is generally beneficial for displaced femoral neck fractures in the elderly. If arthroplasty is chosen, then the type of arthroplasty to be used is decided upon based on the patient's health and functional status, with total hip arthroplasty being the preferred intervention in healthy, active patients that live at home. Finally, there is no evidence in the recent literature that indicates that bipolar hip hemiarthroplasty has a better functional outcome than the unipolar variety, and therefore the use of unipolar implants would probably reduce the economic burden on the healthcare system without compromising patient care.