cssi/SciSciGPT-SciSciNet huggingface dataset:
Half-and-half cells in lichen planus. A possible clue to the origin and early formation of colloid bodies.

SUMMARY In the course of a study of wound healing in four patients with lichen planus, we found transformed keratinocytes with a hitherto undescribed ultrastructure in both wounded and undisturbed papules. We have called these epidermal cells half-and-half cells because they showed changes on the one hand of increased synthetic activity and, on the other hand, of fibrillar transformation closely resembling that seen in fully developed colloid bodies. We suggest that these half-and-half cells may provide a useful clue to the early changes occurring in colloid body formation.
On economically based quality control decisions

Abstract A new approach to the problem of quality control is investigated. It is based on the theories and models developed for optimal maintenance policies for equipment subject to stochastic failure. Four alternative sampling/inspection procedures are examined. They are easy to implement, do not require the process operator to compute his own operating decisions, and are capable of finding optimal intervals between successive samplings/inspections. Both fixed and variable costs are included in the models. Relatively efficient algorithms have been developed for finding the optimal quality control procedures; this is due, partially, to the simple form of the objective function.
DRGs and Specialized Nutrition Support. Prospective Payment and Nutritional Support: The Need for Reform

The Medicare Prospective Payment System does not recognize the use of parenteral and enteral nutrition services as an explicit factor to be used in determination of DRG payment rates. When the DRGs were originally created, the use of parenteral and enteral nutrition services (PENS) was not coded in discharge data sets. As a result, it was impossible to determine whether patients who received PENS were more expensive to treat. Data we have collected indicate that patients who receive PENS tend to have high hospital costs—costs that often exceed the DRG payments established by the Health Care Financing Administration (HCFA). The potential for a hospital to incur a financial loss as a result of treating patients who require PENS could make such patients less attractive to hospitals and thus could adversely affect patients requiring these services. In order to minimize this possibility, we suggest several alternative modifications to the DRG payment system. The modifications would provide higher payments for ...
Latitude Variation of Cosmic Ray Intensity Decreases at Sea-Level

Following a procedure used previously in a mountain altitude calculation, a yield function was combined with the modulation function and primary spectra to obtain the latitude variation of intensity decreases at sea level. Results of the calculations are shown to be in reasonable agreement with experimental data. (W.D.M.)
Russian to English machine translation with simple logical processing

A SKILLED polyglot accomplishes translation from one language to another by translating thoughts; the source-language material is read and digested, and then the thought of the material is formed into target language sentences and recorded. The unskilled translator would translate first on a word-for-word basis, and would then make improvements in the output by consideration of the context of the words. The ultimate in machine translation would be that of translation by thought, as the accomplished polygot would translate, but several fundamental problems remain to be solved before anything of this sort may be accomplished. For instance, there is a great spread between the amount of storage in the human brain and the greatest amount of storage available in any present-day computer. The brain is estimated to have a total storage capacity of 1015 to 1020 bits. The largest of computers stores only about 109 bits, or not over one millionth as much storage as the human brain. A second limitation is that of present knowledge of language. Linguistic knowledge concerning many problems which are vital to machine translation is rather lacking. Thus it would seem that in the present elementary state of the machine translation art the attempt to perform translations should be made more as the unskilled translator does, by basing the translations on the word-for-word translation, and making such improvements as possible from a consideration of the context of the words in the sentence.
Nonlinear theory of a laser with injected atomic coherence.

The influence of injected atomic coherence on a laser's operation is discussed by analyzing the semiclassical equations of motion of this system. Both stationary-steady-state and time-dependent regimes of operation are investigated. We present the dependence of the stationary laser intensity and phase on the external parameters (population inversion, amplitude of atomic coherence, and detuning). For small cavity-field detuning and large atomic coherence, both frequency and phase locking occurs. The laser frequency is locked to the atomic frequency, and the phase is locked to a value determined primarily by the phase of the atomic coherence. Under certain conditions, in the inverted regime, the output intensity is an ssS-shaped function of the atomic coherence, leading to the possibility of a bistable behavior. However, only a portion of the bistable curve gives stable stationary operation, and in critical points (the location of which depends crucially on the external parameters) time-dependent instabilities branch away. When the detuning is larger than a critical value there is neither phase nor frequency locking. We find that the time-dependent behavior of the laser intensity in this case is oscillatory (quasiperiodic), and show that there is a stable limit cycle in the phase plane of the quadratures. There is a small parameter region where a stationary steady state and an oscillatory state may coexist. We also consider the nonlinear quantum theory of a laser with injected atomic coherence, and include the effect of pumping statistics. We derive the Fokker-Planck equation for the P representation, and express the noise in terms of moments. We find that in the steady state the intensity noise can be suppressed below the shot-noise limit but that the phase fluctuations are not affected by pump regularity. For nonzero detuning, we find that transient squeezing of the phase fluctuations is possible.
Abstract PR12: Bringing the outside in: Macropinocytosis and cancer therapeutics

Oncogenic Ras mutations are prevalent in a variety of tumor types, including adenocarcinomas of the pancreas, colon, and lung. One of the most overt phenotypes associated with the expression of oncogenic Ras mutants is the stimulation of macropinocytosis, an endocytic process that involves extensive membrane remodeling and the internalization of extracellular fluid via large membrane-bound vesicles called macropinosomes. The functional consequences of this stimulation in oncogenic Ras-expressing cancer cells were unknown prior to our recent work where we linked macropinocytic uptake to nutrient delivery and amino acid supply in tumor cells. We found that Ras-transformed cells utilize macropinocytosis to internalize extracellular albumin, which is then lysosomally degraded releasing the constituent amino acids intracellularly. These protein-derived amino acids have the capacity to enter central carbon metabolism and fuel tumor cell proliferation even in a nutrient-depleted environment. Of particular relevance is the finding that the pharmacological inhibition of macropinocytosis compromises the growth of Ras-driven pancreatic xenograft tumors. This discovery raises the question of whether the inhibition of macropinocytosis can be utilized as a therapeutic intervention in a subset of cancers. Moreover, because macropinocytosis is an established mechanism of drug delivery for nanoparticles, our work highlights the possibility of exploiting this feature of Ras-induced tumors for the effective delivery of nanoscale therapeutics. Our recent studies focused on identifying novel modulators of macropinocytosis and examining macropinocytosis as a delivery mechanism for nab-paclitaxel, an albumin-based nanoparticle therapy, will be discussed. Citation Format: Cosimo Commisso, Venugopal Chenna, Elda Grabocka, Craig Ramirez, Maitra Anirban, Dafna Bar-Sagi. Bringing the outside in: Macropinocytosis and cancer therapeutics. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr PR12.
Effect of photon-assisted absorption on the thermodynamics of hot electrons interacting with an intense optical field in bulk GaAs

The use of a Boltzmann transport equation with a drift term is physically incorrect for optical-field frequencies. Also, the use of a simple energy-balance equation is found to lead to an inaccurate estimation of electron temperature. Therefore, we have established a Boltzmann-scattering equation for the accurate description of the relative scattering motion of electrons interacting with an incident optical field by including impurity- and phonon-assisted photon absorption as well as Coulomb scattering between two electrons. Multiple peaks on the high-energy tail of a Fermi-Dirac distribution are predicted and the effect of pair scattering is analyzed. Moreover, the effective electron temperature is calculated as a function of both the incident-field amplitude and the photon energy so that the thermodynamics of hot electrons may be investigated.
The effect of hypophysectomy on the regeneration of the liver after partial hepatectomy in dogs.

REGENERATION of the remaining portion of the liver after partial hepatectomy in the dog is rapid and complete within five to eight weeks (Mann, 1927; Fishback, 1929; Bollman and Mann, 1936; Grindlay and Bollman, 1952). Hypophysectomy was found to have little effect on regeneration of the liver in the albino rat if such factors as body growth and intake of food were considered. Franseen and co-workers (1938) and Higgins and Anderson (1931) and Higgins and Ingle (1939) came to the same conclusion, namely, that the retarded restoration of the remaining portion of the liver after the removal of the hypophysial body was largely if not entirely due to reduction in the amount of food consumed by the hypophysectomized rat. Canzanelli and associates (1949), in a more recent study, found great diminution in regeneration and content of nucleic acid of the liver after partial hepatectomy and hypophysectomy.
Technology and Alternative Cancer Therapies: An Analysis of Heterodoxy and Constructivism

Theories of the construction of technology are reviewed from the wider interdisciplinary conversation known as science and technology studies (STS) and from the growing field of the anthropology of science and technology. These theories are used to contribute to research situated at the intersection of the anthropology of alternative medicine and of medical technologies. Cases drawn from the research tradition on microbial theories of cancer are considered to show how unorthodox medical theories become embedded in technologies through choices in microscope design and treatment technologies. In turn, the technologies contribute to the heterodox standing of the researchers, their research, and their therapies.
Acid-catalyzed hydrolysis of maltose and selected maltose derivatives☆

Abstract Acid-catalyzed hydrolysis of maltitol, maltose phenylosotriazole, maltose cyanohydrin, and maltobionic acid differ very little from that of the parent compound, maltose, as determined by energies (30–33 kcal.mole-1) and entropies (+6 to 15 cal.mole-1degree-1) of activation. The hydrolysis of maltose I-phenyl-flavazole, however, had a much lower molar activation energy (13.2 kcal.mole-1) and a much more negative entropy of activation (—46.7 cal.mole-1degree-1). It is suggested that these differences are indicative of a different reaction mechanism for the hydrolysis of the latter compound.
Fine structure of differentiating oocysts and mature sporozoites of Haemoproteus metchnikovi in its intermediate host Chrysops callidus.

SYNOPSIS The fine structure of the sporogonic stages of Haemoproteus metchnikovi has been investigated by electron microscopy. Young oocysts are found beneath the basement membrane of midgut epithelial cells. These eventually protrude outward into the haemocoel space and are surrounded by a distinct oocyst capsule. Sporozoite formation begins with a subcapsular vacuolation. Evagination of the oocyst cytoplasm occurs in regions of membrane thickenings and 100–200 sporozoites are formed about a single sporoblastoid body. Remnants of the ookinete pellicle can be observed in maturing oocysts and always are found in the residual body. The fine structure of the mature sporozoite is essentially similar to that which has been described for other haemosporidia and a spherical body is described in association with the mitochondrion of the sporozoite. The sporogonic stages of H. metchnikovi have features common to the sporogonic stages of Plasmodium and Leucocytozoon that are not held in common by the latter 2 genera, including pattern of sporozoite formation and number of sporozoites formed, the presence of a cytostome and of “crystalloid” in the sporozoite.
Approximations for the random minimal spanning tree with application to network provisioning

This paper considers the problem of determining the mean and distribution of the length of a minimal spanning tree (MST) on an undirected graph whose arc lengths are independently distributed random variables. We obtain bounds and approximations for the MST length and show that our upper bound is much tighter than the naive bound obtained by computing the MST length of the deterministic graph with the respective means as arc lengths. We analyze the asymptotic properties of our approximations and establish conditions under which our bounds are asymptotically optimal. We apply these results to a network provisioning problem and show that the relative error induced by using our approximations tends to zero as the graph grows large.
The biosynthesis of D-galacturonate in plants. Functional cloning and characterization of a membrane-anchored UDP-D-glucuronate 4-epimerase from Arabidopsis

Pectic cell wall polysaccharides owe their high negative charge to the presence of D-galacturonate, a monosaccharide that appears to be present only in plants and some prokaryotes. UDP-D-galacturonate, the activated form of this sugar, is known to be formed by the 4-epimerization of UDP-D-glucuronate; however, no coding regions for the epimerase catalyzing this reaction have previously been described in plants. To better understand the mechanisms by which precursors for pectin synthesis are produced, we used a bioinformatics approach to identify and functionally express a UDP-D-glucuronate 4-epimerase (GAE1) from Arabidopsis. GAE1 is predicted to be a type II membrane protein that belongs to the family of short-chain dehydrogenases/reductases. The recombinant enzyme expressed in Pichia pastoris established a 1.3:1 equilibrium between UDP-D-galacturonate and UDP-D-glucuronate but did not epimerize UDP-D-Glc or UDP-D-Xyl. Enzyme assays on cell extracts localized total UDP-D-glucuronate 4-epimerase and recombinant GAE1 activity exclusively to the microsomal fractions of Arabidopsis and Pichia, respectively. GAE1 had a pH optimum of 7.6 and an apparent Km of 0.19 mm. The recombinant enzyme was strongly inhibited by UDP-D-Xyl but not by UDP, UDP-D-Glc, or UDP-D-Gal. Analysis of Arabidopsis plants transformed with a GAE1:GUS construct showed expression in all tissues. The Arabidopsis genome contains five GAE1 paralogs, all of which are transcribed and predicted to contain a membrane anchor. This suggests that all of these enzymes are targeted to an endomembrane system such as the Golgi where they may provide UDP-D-galacturonate to glycosyltransferases in pectin synthesis.
Robust subspace clustering by combined use of kNND metric and SVD algorithm

Subspace clustering has many applications in computer vision, such as image/video segmentation and pattern classification. The major issue in subspace clustering is to obtain the most appropriate subspace from the given noisy data. Typical methods (e.g., SVD, PCA, and eigen-decomposition) use least squares techniques, and are sensitive to outliers. In this paper, we present the k-th nearest neighbor distance (kNND) metric, which, without actually clustering the data, can exploit the intrinsic data cluster structure to detect and remove influential outliers as well as small data clusters. The remaining data provide a good initial inlier data set that resides in a linear subspace whose rank (dimension) is upper-bounded. Such linear subspace constraint can then be exploited by simple algorithms, such as iterative SVD algorithm, to (1) detect the remaining outliers that violate the correlation structure enforced by the low rank subspace, and (2) reliably compute the subspace. As an example, we apply our method to extracting layers from image sequences containing dynamically moving objects.
Internationalising Counseling Psychology in the United States: A SWOT Analysis

Dans le respect des exigences de cette edition speciale, cet article presente une analyse SWOT du domaine de la psychologie du counseling aux Etats-Unis. Apres un bref survol historique, on passe a la description du contexte des tentatives recentes d’internationalisation de la psychologie du counseling aux Etats-Unis au sein du mouvement multiculturaliste. Le premier plaidoyer en faveur du multiculturalisme initie par la division de psychologie du counseling de l’American Psychological Association est certainement l’un de ses points forts. L’ajout du multiculturalisme international au multiculturalisme local semble etre une evolution naturelle pour le domaine et ouvre un ensemble de nouvelles perspectives. On peut citer, comme voie prometteuse, notre preoccupation recente pour la justice sociale, autre champ majeur d’investigation et d’intervention. Cependant, le domaine de la psychologie du counseling reste menace comme le montre notre statut de «rejeton» de la psychologie clinique. On fait remarquer par la meme occasion qu’une part de nos faiblesses est due a notre incapacite d’exploiter certaines de nos activites de premiere importance telles que la reinsertion, la prevention ou la psychologie positive. Des soucis plus recents ont porte sur le declin organisationnel avec la fermeture d’un nombre important de formations de premier plan en psychologie du counseling. Les raisons de ces disparitions sont toujours sujettes a debat. Consistent with the framework recommended for this special issue, the current article provides a SWOT analysis of the field of counseling psychology within the United States. Beginning with a brief overview of the history of the field, the current analysis moves on to contextualise the recent attempts to internationalise counseling psychology in the United States within the multiculturalism movement. The early advocacy of multiculturalism undertaken by the Division of Counseling Psychology within the American Psychological Association is certainly one of its strengths. The movement to add international multiculturalism to domestic multiculturalism appears to be a natural transition for the field and provides a new set of opportunities. Other opportunities for the field include our recent attention to social justice as another core area of inquiry and intervention. Yet, the field of counseling psychology continues to experience threats as it relates to our “step-child” status vis-a-vis clinical psychology. At the same time, it was noted that part of the weakness of our field has been our failure to capitalise on some of our areas of emphasis such as rehabilitation, prevention, and positive psychology. More recent concerns have centered around organisational decline with the closure of a significant number of the leading counseling psychology training programs in the country. The meaning of these closures continues to be debated.
Torsion fatigue response of self-healing poly(dimethylsiloxane) elastomers

Incorporating self-healing functionality in a polysiloxane elastomer successfully retards the growth of fatigue cracks under torsional fatigue loading. The fully in situ self-healing material consists of a microencapsulated vinyl-terminated poly(dimethylsiloxane) resin containing platinum catalyst compounds and a microencapsulated initiator (methylhydrosiloxane), embedded in a poly(dimethylsiloxane) elastomer matrix. A torsion fatigue test protocol is adopted to assess the self-healing performance of two different elastomeric matrices. Significant recovery of torsional stiffness occurs after approximately 5 h, the time required to achieve a measurable degree of cure of the healing agents. Total fatigue crack growth in a self-healing specimen is reduced by 24% in comparison to relevant controls. The retardation of growing fatigue cracks is attributed, in part, to a sliding-crack-closure mechanism, where polymerized healing agent shields the crack tip from the applied far-field stress.
Limitations of power-spectrum and time-domain analysis of heart rate variability in short-term ECG recorded using telemetry in unrestrained rats

A radio-telemetry technique used to record electrophysiological signals in animals is broadly used in experimental studies. Using implantable probes, this technique can record electrocardiographic (ECG) signals without disturbing animal activities. In this study, we investigated the stability of heart rate variability (HRV) parameters computed from radio-telemetry ECG recordings in unrestrained rats. The experiment involved 4 normal rats in which ECGs were recorded during baseline conditions with and without drug-induced autonomic blockade. The study revealed that the stability of HRV estimators for both time and frequency domain analysis in unrestrained rats was highly dependent on the average heart rate (related to physical rats activity) as well as the length of the ECG recording.
Antifungal Properties of Polymyxin B and Its Potentiation of Tetracycline as an Antifungal Agent

High concentrations of polymyxin B inhibited the growth of Candida albicans and Saccharomyces cerevisiae. When these yeasts were incubated with concentrations of polymyxin B too low to affect growth, and were then exposed to tetracycline, protein synthesis was inhibited and at least 99% of the organisms were killed. Neither inhibition of protein synthesis nor cell death occurred in cultures treated with high concentrations of tetracycline alone. We conclude that polymyxin B at high concentrations affects the cell membrane of yeasts, which results in inhibition of growth. At low concentrations, it increases the permeability of the yeast cell membrane to tetracycline, which then inhibits protein synthesis and leads to cell death.
Evaluation of Item Candidates: The PROMIS Qualitative Item Review

One of the PROMIS (Patient-Reported Outcome Measurement Information System) network's primary goals is the development of a comprehensive item bank for patient-reported outcomes of chronic diseases. For its first set of item banks, PROMIS chose to focus on pain, fatigue, emotional distress, physical function, and social function. An essential step for the development of an item pool is the identification, evaluation, and revision of extant questionnaire items for the core item pool. In this work, we also describe the systematic process wherein items are classified for subsequent statistical processing by the PROMIS investigators. Six phases of item development are documented: identification of extant items, item classification and selection, item review and revision, focus group input on domain coverage, cognitive interviews with individual items, and final revision before field testing. Identification of items refers to the systematic search for existing items in currently available scales. Expert item review and revision was conducted by trained professionals who reviewed the wording of each item and revised as appropriate for conventions adopted by the PROMIS network. Focus groups were used to confirm domain definitions and to identify new areas of item development for future PROMIS item banks. Cognitive interviews were used to examine individual items. Items successfully screened through this process were sent to field testing and will be subjected to innovative scale construction procedures.
Active silicon stimulating microelectrodes and their use in the central auditory system

This paper describes the design of silicon intracortical stimulating microelectrodes for mapping of the functional organization in the central nervous system and potential neural prosthetic applications. Active microelectrodes with different configurations have been developed to facilitate various applications. In-vivo experiments were conducted in selected areas (auditory cortex, DCN, IC) in the auditory pathway of guinea pig models. The stimulating microelectrodes are capable of stimulating neural tissue with controllable current stimuli and selectively stimulating neurons in the DCN to elicit corresponding neural responses in the IC.
Formal Synthesis of (−)‐Englerin A and Cytotoxicity Studies of Truncated Englerins

Scheme 1. Representative structures of natural and synthetic englerins. Abstract: An efficient formal synthesis of (� )-englerin A (1) is reported. The target molecule is a recently isolated guaiane sesquiterpene that possesses highly potent and selective activity against renal cancer cell-lines. Our enantioselective strategy involved the construction of the BC ring system of compound 1 through a Rh II -catalyzed (4+3) cycloaddition reaction followed by subsequent attachment of the A ring through an intramolecular aldol condensation reaction. As such, this strategy allows the synthesis of truncat- ed englerins. Evaluation of these ana- logues with the A498 renal cancer cell- line suggested that the A ring of eng- lerin is crucial to its antiproliferative activity. Moreover, evaluation of these analogues led to the identification of potent growth-inhibitors of CEM cells with GI50 values in the range 1-3 mm.
Dignity and Speech: The Regulation of Hate Speech in a Democracy

The American tradition of free individual expression exists side-by-side with its Fourteenth Amendment commitment to equality. In the area of hate speech, the libertarian notion of free expression comes into tension with the aspiration of equal dignity. While it is evident that maintaining equality means that government has no power to treat the speech of similarly situated persons differently, potential interpersonal friction exists where the speech of one person threatens the rights or safety of another. With the expansion of the Internet, new regulatory challenges more frequently arise because of the global reach of hate propaganda transmitted from the United States, where it is legal, and streamed into countries, like France, where such communications are criminal offenses. The global reach of supremacist ideology creates a challenge to world democracies. Societies committed to pluralism are obligated to safeguard individual expression while promoting egalitarian principles against harming others' safety and dignity. Consequently, as much as American society extols freedom of speech, there are many instances in which competing interests, such as retaining a good reputation in one's community, place restraints on public communications. Where one person wishes to express false statements about another, defamation law sides not with the desire for inaccurate catharsis but with the protection of reputation. The preference for an individual's right to the protection of his own good name 'reflects no more than our basic concept of the essential dignity and worth of every human being.' Public policy favors the interest of libeled individuals over that of anyone wishing to intentionally or negligently spread fallacy. So too where words are likely to result in the immediate breach of the peace. The Supreme Court has found that the government has a countervailing social interest in order and morality that justifies some limitations on speech.This Article opens with a n analysis of hate speech in a democratic society. The first topic to investigate is the role of speech in our constitutional democracy. The current Supreme Court cases that affect the status of hate speech are then reviewed and critiqued. Finally, the Article contrasts the American approach to destructive messages with the European and Canadian models.
A debugger for computational grid applications

The Portable Parallel/Distributed Debugger project at the NASA Ames Research Center has built a debugger for applications running on heterogeneous computational grids. It employs a client-server architecture to simplify the implementation, and its user interface has been designed to provide process control and state examination functions on computations with a large number of processes. The debugger can find processes participating in distributed computations even when those processes were not created under debugger control. In addition to working in a computational grid environment, these techniques also work on other distributed memory jobs, such as those initiated by "mpirun".
A computationally attractive system model using a novel one-sided transformation

Abstract A new representation for systems' dynamic equations is introduced. First, the Householder QR factorization is used to decompose the system matrix. The result is then used to transform the original system model into a specially structured representation via a one-sided transformation. Next, the structural properties of this representation are developed. Then, an example is given to numerically verify the proposed method. Finally, some potential advantages of using such representation, with regard to computational cost and error, in control system analysis and design is discussed.
Origin of post-Minoan caves and volcaniclastic cave fill, Thera (Santorini), Greece

The Aegean island of Thera (Santorini) was covered by tephra from its cataclysmic Late Bronze Age (ca. 3600 yr B.P.) eruption. Vertical exposures of the eruptive sequence show secondary, nonvolcanic, circular (in cross section) features composed of stratified sediment. Many are inaccessible from the floors of modern quarries and appear to be caves filled with younger sediment, but show no connection to the land surface. A filled cave was found in the wall of a modern gully outside the modern quarries, and a filled cave was found in a terrace scarp, well above the modern gully. Natural (and probably rapid) incision by gullies into the thick tephra deposit left many locations with lateral access to tephra. Inhabitants from post-Minoan to recent times excavated tephra for materials and buildings, and caves were subsequently filled by sporadic (possibly seasonal) flood events that deposited sediment. These gullies may have provided access for modern tephra removal that isolated the filled caves high on the modern quarry walls. © 2003 Wiley Periodicals, Inc.
Canopy gaps affect long-term patterns of tree growth and mortality in mature and old-growth forests in the Pacific Northwest

Abstract Canopy gaps created by tree mortality can affect the speed and trajectory of vegetation growth, species’ population dynamics, and spatial heterogeneity in mature forests. Most studies focus on plant development within gaps, yet gaps also affect the mortality and growth of surrounding trees, which influence shading and root encroachment into gaps and determine whether, and how quickly, a gap becomes occupied by recovering vegetation. The objective of this study was to determine the effect of canopy gap size on mortality and growth of surrounding trees over a 16-year period in mature and old-growth Douglas-fir dominated forests in the coastal Pacific Northwest, USA. Replicates of four sizes of experimental gaps and controls were created in two mature stands (90 and 145-years old) and two old-growth stands (overstory trees 350–525-years old); mortality and diameter of surrounding trees were measured periodically over 16 years. A subset of trees was cored to compare growth increment before and after gap creation. There was no difference between mortality rates of trees within 8 m of gaps and trees in closed-canopy controls, although mortality causes did differ for understory trees. Mortality of understory trees was higher at gap edges than in controls, but lower several meters into the forest, suggesting a shift from negative to positive effects with the gradient in exposure. Diameter growth rates of trees were greater next to gaps than in controls, with the greatest difference ranging from 39% for overstory trees to 111% for understory trees in mature stands. Growth rates of trees in old-growth stands differed by crown class and position around gap, suggesting an effect of direct solar radiation. Growth rates of trees in mature stands were relatively insensitive to gap size and position, suggesting that increased soil moisture drove responses in these stands. Somewhat unexpectedly, there were rapid increases in growth in some old-growth trees, but not in the largest gap sizes. Results suggest canopy gaps can create heterogeneity of ecosystem function through spatial variation in effects on growth and mortality across mature and old-growth stands.
Fine-needle aspiration biopsy of metastatic Ewing's sarcoma with MIC2 (CD99) immunocytochemistry

The use of fine-needle aspiration biopsy (FNAB) has been infrequently described as a diagnostic modality for Ewing's sarcoma (ES) patient follow-up and management. The purpose of this study is to examine the use and accuracy of FNAB combined with MIC2 immunocytochemistry for evaluating metastases in patients with ES. Records from Saint Louis University Health Sciences Center and Indiana University Medical Centers identified patients with known ES who had undergone FNAB for evaluation of potential metastases. Immunocytochemical analysis for MIC2 (CD99) was performed retrospectively on cell blocks and direct aspirate smears. FNABs from nine patients were procured either percutaneously or under radiologic guidance and in all cases a definitive cytologic diagnosis of metastatic ES was rendered. Aspirates were cellular with many single discohesive small round cells and occasional loosely cohesive clusters. The nuclei were round with a fine chromatin pattern and small nucleoli. The cytoplasm was scanty and the nuclear-cytoplasmic ratio was high. Six of six cases showed strongly positive immunocytochemical labeling for MIC2. Immunocytochemistry with MIC2 in FNAB aspirate smears can provide supportive evidence of ES in patients with known disease.
Identification of Ovotransferrin as an Acute Phase Protein in Chickens

Inflammation is homeostatic process associated with a variety of cellular injuries resulting from infections, toxicosis, and physical trauma. The studies on inflammation in avian species are limited. To understand the inflammation-induced changes, 4-wk-old male broiler chickens were subjected to experimental inflammation by a subcutaneous injection of croton oil (inflammatory) with changes in serum measured over time and were compared with birds treated similarly with olive oil (injected control). Croton oil treatment significantly elevated serum interleukin (IL)-6 concentrations and heterophil counts by 6 and 16 h postinjection, respectively, which returned to the basal levels of controls at 16 and 24 h, respectively. Croton oil treatment affected the serum protein profiles of chickens as assessed by SDS-PAGE and densitometric analyses. Compared with olive oil-injected or noninjected chicken sera, there were increases in the density of protein bands corresponding to molecular weights (MW) of 42, 65, 200, and 219 kDa and decreases in bands corresponding to 49 kDa (serum albumin) and a 56-kDa protein in chickens treated with croton oil. Most of these changes were evident at 24 h and lasted through 48 h. The protein band corresponding to 65 kDa was further characterized using two-dimensional gel electrophoresis and N-terminal sequence analyses. A sequence similarity search in the Genbank database using the first 22 amino acids yielded a complete homology with chicken ovotransferrin. Western blot analysis using antichicken serum transferrin or antichicken ovotransferrin antibodies also confirmed the 65-kDa protein band to be ovotransferrin. Under nonreducing conditions, the ovotransferrin standard also showed an apparent MW corresponding to 65 kDa, like the serum transferrin. The serum ovotransferrin was found to be glycosylated using a glycoprotein stain. Although the significance of ovotransferrin in avian inflammation is not clear, these results show that it is a major acute phase protein (APP) in chickens.
The Chinese Hamster Dihydrofolate Reductase Replication Origin Decision Point Follows Activation of Transcription and Suppresses Initiation of Replication within Transcription Units

Chinese hamster ovary (CHO) cells select specific replication origin sites within the dihydrofolate reductase (DHFR) locus at a discrete point during G1 phase, the origin decision point (ODP). Origin selection is sensitive to transcription but not protein synthesis inhibitors, implicating a pretranslational role for transcription in origin specification. We have constructed a DNA array covering 121 kb surrounding the DHFR locus, to comprehensively investigate replication initiation and transcription in this region. When nuclei isolated within the first 3 h of G1 phase were stimulated to initiate replication in Xenopus egg extracts, replication initiated without any detectable preference for specific sites. At the ODP, initiation became suppressed from within the Msh3, DHFR, and 2BE2121 transcription units. Active transcription was mostly confined to these transcription units, and inhibition of transcription by alpha-amanitin resulted in the initiation of replication within transcription units, indicating that transcription is necessary to limit initiation events to the intergenic region. However, the resumption of DHFR transcription after mitosis took place prior to the ODP and so is not on its own sufficient to suppress initiation of replication. Together, these results demonstrate a remarkable flexibility in sequence selection for initiating replication and implicate transcription as one important component of origin specification at the ODP.
Some comments on the electrostatic potential of a molecule

In this article we discuss several principles and tools which should expedite description of the electrostatic potentials and electrostatic interactions of molecules, and show that these also lead to some rather remarkable results in the theory of the irreducible representations of the full rotation group SO(3). First, by representing a molecule's charge-density matrix over a basis of atomic-like orbitals (on the various atoms), we observe that outside its charge distribution the molecule's electrostatic potential is exactly the same as if that charge distribution were merely a sum (and in the case of a finite orbital basis, this is a finite sum) of point multipoles on each of the atomic centers and line multipoles on the line segments joining each of those atomic centers. Possible methods of approximating the field of these line charges and line multipoles, as if they were due to point charges and point multipoles, are discussed. The calculation of the interaction of point multipoles of high order, as is necessary for this procedure to successfully calculate the interaction of arbitrarily oriented molecules, motivates our second topic. Here we present a differential operator which, when acting on the 3-dimensional delta function, produces the source density for a scalar field that is exactly an (l,m) multipole field. Using the Hermitian adjoint of this operator, we express the interaction of this (l,m) multipole with an external scalar field as the result of this differential operator acting on that external field at the location of this multipole source. Irreducible representation matrices of the full rotation group are then used, together with these relations, to simplify the interaction of two arbitrarily oriented multipoles of any orders. Finally, we use the representation of the Condon and Shortley “raising and lowering” relations on eigenstates of the z-component of angular momentum, in an orientation that is not aligned with its fundamental basis states, to generate recursion relations that allow simple calculations of the irreducible representation matrices of the full rotation group, SO(3), and the special unitary group, SU(2). From these recursion relations we display some useful symmetry properties of our parameterization of these matrices, that allow the entire matrix to be very simply generated from an explicit calculation of only about 1/8 of its elements. © 1992 John Wiley & Sons, Inc.
Discrete recurrent neural networks for grammatical inference

Describes a novel neural architecture for learning deterministic context-free grammars, or equivalently, deterministic pushdown automata. The unique feature of the proposed network is that it forms stable state representations during learning-previous work has shown that conventional analog recurrent networks can be inherently unstable in that they cannot retain their state memory for long input strings. The authors have previously introduced the discrete recurrent network architecture for learning finite-state automata. Here they extend this model to include a discrete external stack with discrete symbols. A composite error function is described to handle the different situations encountered in learning. The pseudo-gradient learning method (introduced in previous work) is in turn extended for the minimization of these error functions. Empirical trials validating the effectiveness of the pseudo-gradient learning method are presented, for networks both with and without an external stack. Experimental results show that the new networks are successful in learning some simple pushdown automata, though overfitting and non-convergent learning can also occur. Once learned, the internal representation of the network is provably stable; i.e., it classifies unseen strings of arbitrary length with 100% accuracy. >
Gene-Nutrient Interactions and DNA Methylation

Many micronutrients and vitamins are critical for DNA synthesis/repair and maintenance of DNA methylation patterns. Folate has been most extensively investigated in this regard because of its unique function as methyl donor for nucleotide synthesis and biological methylation. Cell culture and animal and human studies showed that deficiency of folate induces disruption of DNA as well as alterations in DNA methylation status. Animal models of methyl deficiency demonstrated an even stronger cause-and-effect relationship than did studies using a folate-deficient diet alone. Such observations imply that the adverse effects of inadequate folate status on DNA metabolism are mostly due to the impairment of methyl supply. Recently, an interaction was observed between folate status and a common mutation in the gene encoding for methylenetetrahydrofolate reductase, an essential enzyme in one-carbon metabolism, in determining genomic DNA methylation. This finding suggests that the interaction between a nutritional status with a genetic polymorphism can modulate gene expression through DNA methylation, especially when such polymorphism limits the methyl supply. DNA methylation, both genome-wide and gene-specific, is of particular interest for the study of cancer, aging and other conditions related to cell-cycle regulation and tissue-specific differentiation, because it affects gene expression without permanent alterations in DNA sequence such as mutations or allele deletions. Understanding the patterns of DNA methylation through the interaction with nutrients is fundamental, not only to provide pathophysiological explanations for the development of certain diseases, but also to improve the knowledge of possible prevention strategies by modifying a nutritional status in at-risk populations.
Ups and downs of guided vessel sprouting: The role of polarity

Blood vessel networks expand to meet oxygen demands via sprouting angiogenesis. This process is heterogeneous but not random; as sprouts form and extend, neighboring endothelial cells do not sprout but divide. Sprouting is regulated by local sprout guidance cues produced by the vessels themselves, as well as extrinsic cues. Endothelial cells in developing vessels orient in several axes to establish migratory polarity, apical-basolateral polarity, and planar cell polarity. Although little is known about how polarity axes are set up or maintained, they are important for vessel formation and function. This review focuses on the current knowledge of how blood vessel sprouting is regulated and guided, the role of endothelial cell polarity in forming vessels, and how these processes affect vessel function and are potentially perturbed in pathologies with vascular components.
Modeling drivers' visual attention allocation while interacting with in-vehicle technologies

In 2 experiments, the authors examined how characteristics of a simulated traffic environment and in-vehicle tasks impact driver performance and visual scanning and the extent to which a computational model of visual attention (SEEV model) could predict scanning behavior. In Experiment 1, the authors manipulated task-relevant information bandwidth and task priority. In Experiment 2, the authors examined task bandwidth and complexity, while introducing infrequent traffic hazards. Overall, task priority had a significant impact on scanning; however, the impact of increasing bandwidth was varied, depending on whether the relevant task was supported by focal (e.g., in-vehicle tasks; increased scanning) or ambient vision (e.g., lane keeping; no increase in scanning). The computational model accounted for approximately 95% of the variance in scanning across both experiments.
Fat Metabolism and Acetoacetate Formation

Publisher Summary This chapter provides an overview of the chemical pathways involved in the metabolism of fatty acids, namely, their breakdown, syntheses, and interconversions with other body constituents. A pivotal point in these pathways is the 2-carbon fragment. In early research, Lipmann—and, independently, Nachmansohn and Berman—discovered that a coenzyme is required for acetylation reactions in the metabolism of fatty acids. From the contributions of many workers, it is now known that the 2-carbon fragment is an acetylated derivative of the coenzyme. The chapter discusses the use and significance of labeling agents, nonisotopic and isotopic as well, in the study of fat metabolism.
Both novelty and conspicuousness influence selection by mammalian predators on the colour pattern of Plethodon cinereus (Urodela: Plethodontidae)

Predators influence the evolution of colour pattern in prey species, yet how these selective forces might differ among predators is rarely considered. In particular, prey colour patterns that indicate unpalatability to some predator species may not carry the same signal for other predators. We test several hypotheses of selection on patterning between mammal predators and the polymorphic salamander Plethodon cinereus, which, under an avian visual system appears as a mimic of the toxic newt Notophthalmus viridescens. We fit each hypothesis against field observations of mammalian attacks on salamander clay replicas. We then develop a novel analytical procedure that enables the combination of multiple non-exclusive models in a likelihood framework. We find that mammals do not follow any single hypothesis proposed, including the hypothesis of mimicry. Instead, mammals in this system use visual cues while foraging to avoid unfamiliar, novel prey and attack conspicuous prey. We propose that mammals may help to maintain colour pattern polymorphism within populations of P. cinereus by avoiding novel, unfamiliar colour morphs. Additionally, selective pressures from multiple predators and variation in predator communities among sites may contribute to the maintenance of colour polymorphism within and among localities in this salamander species.