cssi/SciSciGPT-SciSciNet huggingface dataset:
Graphite furnace atomic absorption spectrophotometers as automated element-specific detectors for high-pressure liquid chromatography

Abstract Techniques for the determination of trace element compounds at ppb 1 and ppm levels (in contrast to the determination of the total element concentration) are a prerequisite for the study of the transformations of trace elements in biological systems and the interactions of trace element compounds with biologically important molecules. Two automated high-pressure liquid chromatography (HPLC) systems with element-specific detectors, capable of detecting, identifying and quantitating trace element compounds were developed independently in our laboratories. One of the detectors consists of a Perkin-Elmer graphite furnace atomic absorption spectrometer (GFAA) and a specially adapted autosampler, whereas a Hitachi-Zeeman GFAA, a sample valve, an injector and associated electronics to control the analysis sequence comprise the components of the other detector. The capability of these systems to speciate trace element compounds is demonstrated using arsenite, arsenate, methylarsonic acid (MAA) and dimethylarsinic acid (DMAA) as examples. Arsenite, MAA and DMAA were successfully separated and quantitatively determined on a strong anion-exchange column with an aqueous acetate buffer as mobile phase. Arsenite, DMAA and arsenate can be speciated with a strong cation-exchange column using an aqueous solution of ammonium acetate as mobile phase. All four arsenic compounds can be separated on a C18 reversed-phase column with methanol-water mixtures saturated with tetraheptylammonium nitrate. These compounds can be identified and quantified in solutions containing 10–20 ppb arsenic. Sample sizes required for GFAA analysis vary between 20 and 100 μl. The separation schemes developed for the four arsenic compounds were used to speciate these compounds in 5 ppb even in rather complex matrices employing a SAX column. Arsenate and arsenite can be determined using a SCX column provided methylarsonate is not present. All four compounds can be separated and quantitated on a C18 reversed-phase column. These separation schemes are applicable to the determination of arsenic compounds in soil extracts and drinking water samples. The separations reported in this paper very likely can be improved by application of columns tailored to arsenic compounds. As an example of column materials development the preparation of reversed-phase cation- and anion-exchange resins is mentioned. These columns were used to separate heterocyclic nitrogen bases and ribonucleoside phosphates12 and should be applicable to the separation of arsenic compounds. Recently the use of a proprietary special anion-exchange column for the separation of arsenic compounds was reported13. Improved column design will make the HPLC-GFAA technique even better suited for the speciation of trace element compounds in a variety of matrices. The work with arsenic compounds clearly shows the great potential of these systems in the area of environmental trace element chemistry, in the field of physiological chemistry and in trace-element related nutritional studies.
A Phase 1 Trial of Intravenous Boronophenylalanine-Fructose Complex in Patients with Glioblastoma Multiforme

Seven patients with glioblastoma multiforme received 2-hour intravenous infusions of p-boronophenylalanine (BPA) prior to craniotomy. The BPA was solubilized for injection by complexation with fructose. Administered BPA doses were 100mg BPA/kg (n=1), 130 mg BPA/kg (n=5) and 170 mg BPA/kg (n=1). The boron concentration in blood was proportional to the administered dose. The boron concentrations in scalp were 1-2 times higher than the corresponding boron concentration in the blood. The boron concentrations in the tumor (range, 11–26µg 10B/g) were from 1–4 times the corresponding levels in the blood.
A practical approach to clinical and research biobanking

Powerful technologies critical to personalized medicine and targeted therapeutics require the analysis of carefully validated, procured, stored, and managed biospecimens. Reflecting advancements in biospecimen science, the National Cancer Institute and the International Society for Biological and Environmental Repositories are periodically publishing best practices that can guide the biobanker. The modern biobank will operate more like a clinical laboratory with formal accreditation, standard operating procedures, and quality assurance protocols. This chapter highlights practical issues of consent, procurement, storage, quality assurance, disbursement, funding, and space. Common topics of concern are discussed including the differences between clinical and research biospecimens, stabilization of biospecimens during procurement, optimal storage temperatures, and technical validation of biospecimen content and quality. With quickly expanding biospecimen needs and limited healthcare budgets, biobanks may need to be selective as to what is stored. Furthermore, a shift to room-temperature storage modalities where possible can reduce long-term space and fiscal requirements.
Rethinking Information and Communications Technology Policy Focus on Internet versus Teledensity Diffusion for Africa's Least Developed Countries

The digital divide between the West and Africa seems to be drawing closer for many northern and southern African countries in terms of information and communications technology. These countries are experiencing tremendous growth in use of computers, Internet connectivity, wireless communications and many other related technologies. However, the same is not true for Africa?s Least Developed Countries (LDCs) that are still greatly behind other regions of the world in terms of the level of basic telecommunications infrastructure such as teledensity (number of main telephone lines for every one hundred inhabitants). While it is true that Africa?s LDCs have some Internet presence, it seems to be limited only to the urban elite. These countries may therefore not be in the position to exploit most of the benefits the Internet can offer. This study suggests a sound teledensity infrastructure as the precursor to the diffusion of various information and communications technologies. Furthermore this study proposes a set of strategies that Africa?s LDCs should consider as steps to improve growth of their teledensity.
An algorithm to reduce automated emission measurement data

When performing automated measurement of electromagnetic interference (EMI) emission characteristics of an equipment, the resulting data sets can contain hundreds or thousands of data points. From the standpoint of an engineer trying to assess the electromagnetic compatibility (EMC) of the equipment in a particular platform, the envelope of the emission spectrum is typically of greatest importance. It is desirable to have an automated method of reducing the large data set into a compact set that contains only those points which represent a close approximation to the spectrum envelope. An algorithm has been developed which performs automated reduction of emission data. The degree of reduction can be varied by the user through the choice of two parameters. Trial results show that the algorithm performs very well in approximating the envelope of typical emission curves. >
The p-adic L-function

In this chapter we return to p-adic integration theory, and give Mazur’s formulation of the p-adic L-function as Mellin transform. It turns out to be more convenient as a basic definition, than Iwasawa’s previous formulation in terms of power series. The connection is made via Example 2 of §1. We derive further analytic properties, which allow us to make explicit its value at s = 1, thereby obtaining Leopoldt’s formula in the p-adic case, analogous to that of the complex case. We also give Leopoldt’s version of the p-adic class number formula and regulator.
Model of yield response of corn to plant population and absorption of solar energy.

Biomass yield of agronomic crops is influenced by a number of factors, including crop species, soil type, applied nutrients, water availability, and plant population. This article is focused on dependence of biomass yield (Mg ha−1 and g plant−1) on plant population (plants m−2). Analysis includes data from the literature for three independent studies with the warm-season annual corn (Zea mays L.) grown in the United States. Data are analyzed with a simple exponential mathematical model which contains two parameters, viz. Ym (Mg ha−1) for maximum yield at high plant population and c (m2 plant−1) for the population response coefficient. This analysis leads to a new parameter called characteristic plant population, xc = 1/c (plants m−2). The model is shown to describe the data rather well for the three field studies. In one study measurements were made of solar radiation at different positions in the plant canopy. The coefficient of absorption of solar energy was assumed to be the same as c and provided a physical basis for the exponential model. The three studies showed no definitive peak in yield with plant population, but generally exhibited asymptotic approach to maximum yield with increased plant population. Values of xc were very similar for the three field studies with the same crop species.
From receiver operating characteristic to system operating characteristic: evaluation of a track formation system

The authors discuss the application of multitarget tracking techniques in combination with a Markov chain model to the evaluation of a track formation system based on a composite logic. Target track detection probability is computed in the presence of false alarms. The target track detection probability versus the false track probability is plotted; the values of target detection probability and the false alarm probability are varied to conform to the system's operating signal-to-noise ratio. This allows choice of the detector's operating point so to satisfy the overall system requirements. A procedure for inferring the overall system capacity in terms of the minimum spacing of targets that ensures tracking with a certain reliability is presented. The entire methodology is illustrated by a case study of an actual system. >
Case-Based Retrieval Approach of Supporting Process Planning in Layer-Based Additive Manufacturing

The process planning task for a given design problem in additive manufacturing can be greatly enhanced by referencing previously developed process plans. In this research, a case-based retrieval method, called the DFM (Design For Manufacturing) framework, that retrieves previously formulated process plans is proposed to support process planning. To support the DFM Framework, we have developed an information model (ontology) of manufacturing process knowledge in the domain of additive manufacturing processes, including design requirements, process plans, and rules that map requirements to plans. Description Logic (DL) is identified as an appropriate mathematical formalism to encode the ontology and realize the computational mapping between the design and manufacturing domains. Storage and retrieval algorithms are presented that, first, structure the repository of previous DFM problems and, second, enable DFM problems to be retrieved.© 2007 ASME
Genetic Analysis of the HAMP Domain of the Aer Aerotaxis Sensor Localizes Flavin Adenine Dinucleotide-Binding Determinants to the AS-2 Helix

HAMP domains are signal transduction domains typically located between the membrane anchor and cytoplasmic signaling domain of the proteins in which they occur. The prototypical structure consists of two helical amphipathic sequences (AS-1 and AS-2) connected by a region of undetermined structure. The Escherichia coli aerotaxis receptor, Aer, has a HAMP domain and a PAS domain with a flavin adenine dinucleotide (FAD) cofactor that senses the intracellular energy level. Previous studies reported mutations in the HAMP domain that abolished FAD binding to the PAS domain. In this study, using random and site-directed mutagenesis, we identified the distal helix, AS-2, as the component of the HAMP domain that stabilizes FAD binding. AS-2 in Aer is not amphipathic and is predicted to be buried. Mutations in the sequence coding for the contiguous proximal signaling domain altered signaling by Aer but did not affect FAD binding. The V264M residue replacement in this region resulted in an inverted response in which E. coli cells expressing the mutant Aer protein were repelled by oxygen. Bioinformatics analysis of aligned HAMP domains indicated that the proximal signaling domain is conserved in other HAMP domains that are not involved in chemotaxis or aerotaxis. Only one null mutation was found in the coding sequence for the HAMP AS-1 and connector regions, suggesting that these are not active signal transduction sites. We consider a model in which the signal from FAD is transmitted across a PAS-HAMP interface to AS-2 or the proximal signaling domain.
Effective use of radiation shields to minimize operator dose during invasive cardiology procedures.

Objectives This study sought to measure the protection from scatter radiation offered to the primary physician by a variety of available shields and to provide best practice guidelines for shield use during invasive cardiology procedures. Background It is accepted that exposure to radiation includes a predicted increase in cancer risk. In the cardiac interventional laboratories, radiation shields are widely available; however, proper use of the shields to optimize protection during cardiac interventional procedures is not well understood. Methods The protection from scatter radiation offered by a variety of shields used alone and in combination was measured. Protection was assessed from air-kerma measurements of scatter radiation from a phantom performed without and with the shields. Protection was assessed for 3 patient- access locations (right jugular vein, right femoral artery, and left anterior chest) and for elevations ranging from 25 to 175 cm from the floor. The influence of precise placement of the ceiling-mounted upper body shield was specifically assessed. Results The utility and protection of shielding varied for the 3 access points and with elevation. For femoral artery access locations, the shields can provide at least 80% protection from scatter at all elevations; however, protection depends substantially on upper body shield position. A disposable radiation-absorbing pad can provide 35% to 70% upper body protection for procedures during which the upper body shield cannot be used effectively. Conclusions Radiation shields can provide substantial protection from radiation during cardiac interventional procedures. Shields must be thoughtfully and actively managed to provide optimum protection. Best practice guidelines for shield use are provided.
Vascular radiation in a drug-eluting stent world: it's not over till it's over.

Have you ever wondered how those who developed the iron lung for victims of polio felt about Jonas Salk? Given the promise of drug-coated stents, one wonders if the extensive work done in perfecting vascular brachytherapy may soon be valued only as an historical anecdote. After innumerable therapeutic failures, vascular brachytherapy was the first effective antiproliferative treatment for restenosis. To date, more than a dozen randomized trials have demonstrated its safety and efficacy.1–11 After redilatation of in-stent restenosis, brachytherapy reduces the risk of subsequent recurrence by ≈50%. Its adoption by the interventional cardiology community was widespread and extraordinarily rapid. Today, less than 3 years after FDA approval, brachytherapy is used in more than 400 US catheterization laboratories, and each year >40 000 patients receive brachytherapy for in-stent restenosis. The current enthusiasm for drug-eluting stents, however, may soon make vascular brachytherapy obsolete. Drug-coated stents may abolish, or nearly abolish, in-stent restenosis. Because coronary brachytherapy has only been proven effective as a treatment for in-stent restenosis, its fate in the drug-eluting stent world is uncertain. When drug-eluting coated stents are widely available, vascular brachytherapy risks being discarded just as quickly as it was embraced only a few years ago. Will drug-coated stents transform vascular brachytherapy into a cure without a disease? Let’s examine the evidence. As of October 2002, we have data from numerous large randomized trials. The largest of these, a randomized, double-blind study of the SIRolImUS-eluting …
Are Environmental Protection Agency Approved Total Maximum Daily Loads Consistent in Their Use of Sound Data and Analysis

The recent National Research Council ~NRC! report, Assessing the TMDL Approach to Water Quality Management ~National Academy Press, 2001! recommends steps that are necessary to improve all phases of the total maximum daily load ~TMDL! development process. Most importantly, the NRC experts felt ‘‘that the data and science have progressed sufficiently over the past 35 years to support the nation’s return to ambient-based water quality management.’’ The executive summary states that ‘‘given reasonable expectations for data availability and the inevitable limits on our conceptual understanding of complex systems, statements about the science behind water quality management must be made with acknowledgment of uncertainties.’’ The report further states, ‘‘the Committee has concluded that there are creative ways to accommodate this uncertainty while moving forward in addressing the nation’s water quality challenges.’’ The NRC report is undoubtedly correct, but the information and experience held by the committee may not be shared at all technical levels represented among those charged with preparation of TMDLs for the nations waterways. Beginning in 2000, for example, the Government Accounting Office ~GAO! addressed several issues related to TMDL development—particularly the adequacy of data resources used by states in listing impaired waters and developing TMDLs. If the data on which the process was founded is flawed, how likely is it that model-derived water quality impacts—leading to management options to bring listed stream segments into compliance—will be useful. EPA approval of TMDLs based on inadequate data will lead to load allocations that are inconsistent and may be unfair to stakeholders when implemented. Relevant reports cited by the GAO include
Signals and Systems II Part I: Signals and their representations

The goal of this series is a principles-based capability to design signal-processing architectures to convert signals between various forms. Signals are continuous-time or discrete-time, real or complex, and baseband or passband. Operations used on those signals include analog filtering, digital filtering, interpolation, decimation, and frequency shifts. The approach is rigorous but largely graphical with little explicit mathematics.
QT Interval Prolongation as a Biomarker for Torsades de Pointes and Sudden Death in Drug Development

Prolongation of the QT interval on the surface 12-lead electrocardiogram is widely accepted as a biomarker for the potential of a drug to produce torsades de pointes and/or sudden death. Detection of drug-induced prolongation of the QT interval in animals and man is frequently confounded by extrinsic and intrinsic factors that limit the ability to detect a true drug effect. In particular drugs that increase heart rate show an apparent increase in QT interval that confounds assessment of a true drug effect on cardiac ventricular repolarization. The basis for the use of the QT interval as a biomarker will be examined.
Suppression of an IL-13 Autocrine Growth Loop in a Human Hodgkin/Reed-Sternberg Tumor Cell Line by a Novel IL-13 Antagonist

IL-13 has been proposed to be an autocrine growth factor for Hodgkin/Reed-Sternberg tumor cells (H/RS cells). Since we have recently identified and produced a novel IL-13 antagonist (IL-13E13K) that can suppress the biological activity of IL-13, here we examined whether IL-13E13K can inhibit growth of Hodgkin lymphoma (HL)-derived cell lines. IL-13E13K not only inhibited the growth of an unstimulated H/RS cell line (L1236) but also cells that were stimulated by exogenous IL-13 in a dose-dependent manner. Several HL-derived cell lines expressed IL-13 message and protein and message for various chains of IL-13R. H/RS cell lines expressed mRNA for the IL-13R alpha 1, IL-4R alpha, and IL-2R gamma chains. However, none of these cell lines expressed the IL-13R alpha 2 chain. An H/RS cell line (L1236) internalized the ligand-receptor complex after binding to a fusion protein composed of IL-13 and a mutated form of Pseudomonas exotoxin A (IL-13-PE38QQR, or IL-13 cytotoxin), as IL-13 cytotoxin was specifically cytotoxic to H/RS cells in vitro. These results indicate that IL-13E13K and IL-13 cytotoxin can effectively suppress growth of a L1236 H/RS cell line. Therefore, additional studies should be performed to determine the expression of IL-13 and IL-13R in primary clinical samples of Hodgkin's lymphoma and both agents should be further tested in vitro and in vivo as possible therapeutic agents for HL.
Mental and Biophysical Terrains of Biodiversity: Conserving Oak on Family Forests

This research explores the mental and biophysical terrains of family forest owners' relationships with biodiversity. We used concept mapping, in-depth unstructured interviews, property mapping, and field observation to explore owners' knowledge, beliefs and management approaches. We conducted our research in one watershed in the Oregon white oak (Quercus garryana) ecotype of western Oregon, an ecotype that is considered at risk. The owners in our sample are knowledgeable about the concept of biodiversity and believe they should steward the biodiversity of their forests through management. However, their notion of biodiversity appears to be quite generic, rather than specific to the oak ecotype in which they own land. Moreover, external economic and social forces encourage them to manage for Douglas fir rather than oak. Extending Schneider and Ingram's (1990) theoretical policy framework to conservation, we propose ways for policy to address these limitations and build on owners' motivations.
Moscow Does Not Believe in Tears: From Oscar to consolation prize

AbstractThe article traces the changing status of Vladimir Men'shov's Oscar-winning film, Moscow Does Not Believe in Tears (1979). This film, lauded by Hollywood for its ‘apolitical’ celebration of three women in Brezhnev's Russia, has nonetheless gone through various, more complex interpretations by various audiences, both at home and abroad. A movie known in the West as a Soviet success on the red carpet, this film has today inspired a new, very different generation of Russian television heroines in serialized dramas. What appears to us a Cinderella story is now seen at home as the foundation for sadder, ‘consolatory’ tales. Ironically, the ability to forge a career and find a husband has become so difficult in modern Moscow that Men'shov's film is today endlessly, ironically referenced as a tale that should come true — but. never does.
PRODUCTION TECHNOLOGY, NONDEBT TAX SHIELDS, AND FINANCIAL LEVERAGE

In the literature a negative relationship between debt and nondebt tax shields is predicted only for firms that have the same production technology (i.e., firms with perfectly correlated pretax output). In this paper we examine the relationship between production technology and differences in firms' financial leverage ratios, and find that firms in the same industry with highly (lowly) correlated output make similar (dissimilar) leverage decisions. Thus, the correlation of output across states of nature helps explain leverage differences that are not explained by industry differences. Contrary to previous predictions, however, leverage differences for firms with highly correlated pretax output suggest a positive relationship between debt and nondebt tax shields.
Ocean of information: fusing aggregate & individual dynamics for metropolitan analysis

In this paper, we propose a tool to explore human movement dynamics in a Metropolitan Area. By analyzing a mass of individual cell phone traces, we build a Human-City Interaction System for understanding urban mobility patterns at different user-controlled temporal and geographic scales. We solve the problems that are found in available tools for spatio-temporal analysis, by allowing seamless manipulability and introducing a simultaneous\multi-scale visualization of individual and aggregate flows. Our tool is built to support the exploration and discovery of urban mobility patterns and the daily interactions of millions of people. Moreover, we implement an intelligent algorithm to evaluate the level of mobility homophily of people moving from place to place.
Perspective-taking in dialogue as self-organization under social constraints

Abstract We present a dynamical systems account of how simple social information influences perspective-taking. Our account is motivated by the notion that perspective-taking may obey common dynamic principles with perceptuomotor coupling. We turn to the prominent HKB dynamical model of motor coordination, drawing from basic principles of self-organization to describe how conversational perspective-taking unfolds in a low-dimensional attractor landscape. We begin by simulating experimental data taken from a simple instruction-following task, in which participants have different expectations about their interaction partner. By treating belief states as different values of a control parameter, we show that data generated by a basic dynamical process fits overall egocentric and other-centric response distributions, the time required for participants to enact a response on a trial-by-trial basis, and the action dynamics exhibited in individual trials. We end by discussing the theoretical significance of dynamics in dialog, arguing that high-level coordination such as perspective-taking may obey similar dynamics as perceptuomotor coordination, pointing to common principles of adaptivity and flexibility during dialog.
Induced asymmetry in the prosthetic group of rhodopsin

Abstract The optical rotatory dispersion technique is used to investigate the induced asymmetry of the prosthetic group of rhodopsin. A Cotton effect is generated in the visible which is attributed to 11- cis retinal. In another part of the experiment, a double-flash technique is used to irradiate meta II thus photoreversing it to stable rhodopsin. It is found that the retinal of photoreversed rhodopsin exhibits as much induced asymmetry as the one in native (freshly extracted) rhodopsin.
Reverse Wenckebach Block and Complete Atrioventricular Dissociation due to Potassium and Digitalis

The relation of digitalis to potassium was studied by administering potassium intravenously before and after digitalization. The disturbances of conduction due to potassium and those occurring after digitalis were observed and are here discussed.
Cell Fusion Induced by Herpes Simplex Virus Glycoproteins gB, gD, and gH-gL Requires a gD Receptor but Not Necessarily Heparan Sulfate

To characterize cellular factors required for herpes simplex virus type 1 (HSV-1)-induced cell fusion, we used an efficient and quantitative assay relying on expression of HSV-1 glycoproteins in transfected cells. We showed the following: (1) Cell fusion depended not only on expression of four viral glycoproteins (gB, gD, and gH-gL), as previously shown, but also on expression of cell surface entry receptors specific for gD. (2) Cell fusion required expression of all four glycoproteins in the same cell. (3) Heparan sulfate was not required for cell fusion. (4) Coexpression of receptor with the four glycoproteins in the same cell reduced fusion activity, indicating that interaction of gD and receptor can limit polykaryocyte formation. Overall, the viral and cellular determinants of HSV-1-induced cell fusion are similar to those for viral entry, except that HSV-1 entry is significantly enhanced by binding of virus to cell surface heparan sulfate.
Environmental psychology or behavioral geography? Either way it was a good start

The paper traces the author's background as a British geographer and the intellectual climate at Clark University in 1968 which led him out of urban social geography into the uncharted domain of children's knowledge of the geographic environment. Following the integration of theory and research on the development of spatial cognition in children came the need to investigate child development in relation to the physical landscape more comprehensively in a Ph.D. dissertation. Subsequent work, built entirely from this early base, continues to investigate children's use, knowledge and experience of physical environment in a variety of settings. Applications of research are made in both the fields of environmental education and environmental planning and design.
The impact of total enteral nutrition on distraction osteogenesis in a rat model.

Limb lengthening by gradual mechanical distraction, termed distraction osteogenesis (DO), results in new bone formation. We have developed a rat tibial model for DO and have proceeded to study the effects of nutrition on this process. We have combined the intragastric diet delivery system of total enteral nutrition (TEN) with DO in the rat model. The first study was designed to address the weight loss associated with DO in dogs and patients. Rats in the chow + DO group lost 10% body weight over the 20-day distraction period but gradually gained weight back to the preoperative level by the end of the 5th week of the bone consolidation period. In contrast, in the TEN + DO group, a weight gain was recorded during the 20-day distraction phase. A second study was conducted to determine the effects of TEN on the rate and histology of regenerate bone formation. The weight changes replicated those seen in the first study. Standardized radiographs, taken on day 20, revealed increases (p > 0.003) in regenerate bone formation in the TEN group when compared with the chow group. Increased numbers of osteoclasts in the TEN group may indicate an accelerated entry into the remodeling phase of consolidation. Serum IGF-I values, taken at day 20, did not differ between the groups. These results demonstrate that the nutritional support dramatically increased the mineralized bone formed over the 20-day distraction period. (J Bone Miner Res 1996;11:962–969)
Testing the equality of the smallest latent roots of a correlation matrix

SUMMARY The asymptotic variance of a statistic used to test the equality of the smallest latent roots of a correlation matrix is computed. This permits an approximation to its null distribution suggested by Lawley (1956). A simulation is used to compare the performance of this approximation with others currently in use.
The frequency of marker changes in sugarcane plants regenerated from callus culture

This study investigates the frequency of apparent and permanent expression of marker change following two types of tissue culture, conventional callus and direct regeneration cultures, and for two markers it relates this frequency to that following breeding. Each clone was used for only one marker. After conventional callus culture, plants of the sugarcane clone Arundoid B, a clone having a growth habit with shortened internodes and leaves, were freed of this marker at a rate of 1 in 172 plants. Marker remission in a second clone with a leaf blotch was enhanced in the presence of a mutagen. Callus culture alone gave a remission rate of 1/280 plants, while treatment of callus with ethyl methanesulfonate gave a remission rate of 1/42 plants. Of two markers subjected to vegetative and sexual transmission, the first, a leaf marker, was stable in callus culture with no remissions; crossing with non-marker parents produced progeny with 54% lacking the marker. The second, a stalk marker (multibud), showed epigenetic effects during two generations of vegetative propagation; plants lacking the multibud marker produced vegetative progeny in which the marker reappeared. Nine crosses to nonmarker parents produced progeny of which an average of 29% had the marker. The use of stalk chimeras as markers demonstrated that passage through conventional callus or direct regeneration culture resulted in the loss of the donor phenotype in all plants regenerated. Phenotypic variation in plants derived from callus culture appears to arise from several sources; chimeral segregants, epigenetic transients, and mutational variants.
The use of ventricular pacing for suppression of ectopic ventricular activity

Abstract In 13 patients with acute myocardial infarction, digitalis toxicity or recent cardiac surgery, ventricular pacing was found to be of value for control of ectopic ventricular beats. In 12 of the 13 pacing alone was found to produce complete suppression, whereas the thirteenth required both pacing and beta adrenergic blockade with propranolol to prevent ventricular tachycardia resistant to either alone. The indications for pacing in these patients were found to be lack of response to standard drugs, underlying bradyarrhythmias or heart block, presumed allergy to suppressive agents or fear of myocardial depression by drugs. The advantages of pacing for suppression of ectopic ventricular beats are discussed, and possible electrophysiologic mechanisms by which ventricular pacing is effective in control of the irritable heart are reviewed.
Genes del desarrollo y enfermedad cardíaca

The past three years can be considered in cardiology as critical for understanding the relevance of developmental genes in the adult cardiac physiology. Also, for the first time, endogenous control of programmed cell death has been demonstrated to mark the transition between normal adaptation and cardiac hypertrophy. Most of this work has been based on previous analysis using molecular markers of cardiac determination and differentiation, work that has served a double aim: First, the determination of the cellular process that contribute to the specification of the working heart and secondly, the characterization of key regulatory factors in cardiogenesis. These studies in conjunction with the recent availability of single gene mutation in transgenic mice have furnished a new perspective in the nature of cardiac defects either in shape or function. Here we review some of the key factors in cardiac morphogenesis from the perspective of the analysis of gene mutation.
Inhibition of the phosphodiesterase activity of commercial E. coli phosphatase

Abstract Phosphatases are used to determine the chain length of oligonucleotides. Contamination by phosphodiesterases may cause the nucleotide chain to appear shorter than it really is. To circumvent this difficulty, Furlong (1) suggested digestion with E. coli alkaline phosphatase at 60° in the presence of 2.5–4 M salt. These conditions increase the phosphatase activity, but unfortunately, as shown in this paper, cause a concomitant increase in phosphodiesterase activity. It is possible to inhibit the phosphodiesterase activity completely and the alkaline phosphatase activity minimally, by adjusting the reaction mixture containing 2.5 M NaCl to 700 μM in EDTA.
The effect of non-convertible preferred stock retirement on shareholder wealth

In this paper the authors examine the common stock price behavior of firms that call their non-convertible preferred stock. The findings for the entire sample of preferred stock calls are consistent with the Modigliani and Miller (MM) leverage hypothesis that preferred stock financing adds no value to the firm. However, for those firms whose preferred stock was completely eliminated from the capital structure, a significant, positive announcement effect is observed. This finding is consistent with an information signaling effect related to the earnings prospects and tax status of the calling firms and also is suggestive of a burdensome covenant effect. No evidence is found to support the free cash flow theory of common stock price reactions to preferred stock calls.
Modifications of mammalian cell surfaces induced by sugars: Scanning electron microscopy

Abstract Substitution of galactose, xylose, or mannose for glucose in the growth medium of L cells or the addition of equal concentrations of the alternate sugars to glucose-containing medium results in marked morphologic changes. The changes are revealed by conventional staining for light microscopy and by scanning electron microscopy. L cells grow indefinitely on combinations of equal concentrations of glucose and galactose, xylose, or mannose. There appear to be no significant differences in growth rate on glucose compared to the combinations of sugars cited. Cells subcultured from glucose to the combinations while undergoing rapid multiplication show marked morphologic changes by light and scanning electron microscopy within 36 hr. Of particular note are the loss of microvilli; flattening of the cells; assumption of polygonal shape; prominence of nuclei and nucleoli; and changes in the structure and distribution of filopodia. Virtually all cells in the population exhibit the changes noted.
Clarifying cougar management in Oregon.

I am concerned that V. Morrell's Science Now article “Oregon cougars to be hounded” ( ; posted 29 June) may lead readers to misconstrue how the passage of the new law, HB 2971, affects cougar management in the state. HB 2971 does not
Algebraic rotating-frame approach to electron-molecule scattering.

An approach to electron scattering from molecules is discussed, in which an algebraic description of the rovibrational states in the molecule (vibron model) is combined with a rotating-frame approximation. The latter was first introduced for atomic-molecule scattering under the name centrifugal sudden approximation. The coupled multichannel problem reduces to single-channel central potential scattering with a fluctuating potential. The method is applied to electron scattering from a rigid molecule with large dipole moment. Comparison with exact coupled-channel calculation shows that the approach works well for all partial waves except those with very low angular momentum. The method is also compared with the algebraic eikonal approach.
The impact of a building implosion on airborne particulate matter in an urban community.

Abstract In response to community concerns, the air quality impact of imploding a 22-story building in east Baltimore, MD, was studied. Time- and space-resolved concentrations of indoor and outdoor particulate matter (PM) (nominally 0.5–10 µm) were measured using a portable nephelometer at seven and four locations, respectively. PM10 levels varied in time and space; there was no measurable effect observed upwind of the implosion. The downwind peak PM10 levels varied with distance (54,000–589 µg/m3) exceeding pre-implosion levels for sites 100 and 1130 m 3000- and 20-fold, respectively. Estimated outdoor 24-hr integrated mass concentrations varied from 15 to 72 µg/m3. The implosion did not result in the U.S. Environmental Protection Agency (EPA) National Ambient Air Quality Standard (NAAQS) for PM10 being exceeded. X-ray fluorescence analysis indicated that the elemental composition was dominated by crustal elements: calcium (57%), silicon (23%), aluminum (7.6%), and iron (6.1%). Lead was above background ...
Immunological control of hematophagous arthropod vectors: utilization of novel antigens.

Abstract Immunological control of ixodid ticks requires development of a vaccine that stimulates an effective anti-tick response. However, it is important to avoid induction of intense host skin reactivity to tick feeding. Salivary-gland-derived molecules are introduced into the host during ixodid engorgement; therefore, use of these moieties might not be an optimal immunization strategy. Antigens not normally involved in acquired resistance can be used to induce anti-tick immunity. These “novel” antigens, obtained from tick gut absorptive surface, are not introduced into the host during tick feeding, but are exposed to host-immune effector elements in the blood meal, resulting in ixodid rejection, prevention of ova production and death. Anti-tick immunity is induced with microgram quantities of this ixodid gut antigen preparation. Sera obtained from immunized animals were used to identify antibody-reactive components of the resistance-inducing extract. Tick gut absorptive surface antigen glycoconjugates were identified by lectin blotting, using a series of probes with different carbohydrate specificities. The lectins, peanut and wheat germ agglutinin, and immunized host antibodies bound extract components with similar molecular weights. Solubilization and fractionization of tick gut proteins with the non-ionic detergent Triton X-114 is described.
Appearances can be deceiving

Dick-Biascoechea. Appearances can be deceiving. Am J Obstet Gynecol 2014. Case notes An 82-year-old patient complained to her gynecologist about 6 months worsening vaginal prolapse, pelvic pressure, and a constant urge to void and defecate. She had used a pessary, which she was unable to replace. Pelvic examination revealed a gaping introitus with an apparent stage 3 posterior vaginal prolapse (Figure 1). Speculum examination was not possible because of a mass displacing the vagina anteriorly. Magnetic resonance imaging showed a 16 8.8 6.5ecm cystic mass anterior to the rectum (Figure 2). The differential diagnosis included a tailgut cyst vs rectal duplication. The patient was taken to the operating room by a team of gynecologic oncologists and colorectal surgeons. They found a large mass in the left ovary, directly contiguous with the uterus and rectosigmoid colon that dissected the rectovaginal septum down to the perineum, ascites, an omental cake that involved the transverse colon, and enlarged periaortic lymph nodes. A total abdominal hysterectomy (bilateral salpingo-oophorectomy [Figure 3], en-bloc resection of the tumor that included the rectosigmoid colon [Figure 4], proctectomy with descending end colostomy omentectomy, periaortic lymphadenectomy, and tumor debulking) was performed. The final pathologic report confirmed a high-grade serous carcinoma that involved the ovaries, fallopian tubes, uterine serosa, rectosigmoid colon, and omentum. Periaortic and mesenteric nodes contained metastatic cancer. The patient was discharged from the hospital to a skilled nursing facility for short-term rehabilitation after 15 days and has just completed adjuvant carboplatin and paclitaxel.
Crossbreds of Jersey × Holstein Compared with Pure Holsteins for Production, Fertility, and Body and Udder Measurements During First Lactation

Jersey x Holstein crossbreds (JxH; n = 76) were compared with pure Holsteins (n = 73) for 305-d milk, fat, and protein production; conception rate; days open; proportion of cows pregnant within fixed intervals postpartum; and body and udder measurements during first lactation. Cows were housed at 2 research locations of the University of Minnesota and calved from September 2003 to May 2005. The JxH were mated to Montbeliarde sires, and Holstein cows were mated to Holstein sires. Best Prediction was used to determine actual production (milk, fat, and protein) for 305-d lactations with adjustment for age at calving, and records less than 305 d were projected to 305 d. The JxH (274 kg) and pure Holsteins (277 kg) were not significantly different for fat production, but JxH had significantly less milk (7,147 vs. 7,705 kg) and protein (223 vs. 238 kg) production than pure Holsteins. The JxH had significantly fewer days open than pure Holsteins (127 vs. 150 d). Also, a significantly greater proportion of JxH were pregnant at 150 and 180 d postpartum than pure Holsteins (75 vs. 59% and 77 vs. 61%, respectively). The JxH had significantly less body weight (60 kg) at calving, but significantly greater body condition (2.80 vs. 2.71). Furthermore, JxH had significantly less udder clearance from the ground to the bottom of the udder than pure Holsteins (47.7 vs. 54.6 cm), and greater distance between front teats (15.8 vs. 14.0 cm) than pure Holsteins during first lactation.
Who Should Receive Neoadjuvant Chemotherapy Prior to Liver Resection for Colorectal Carcinoma Liver Metastases

The role for neoadjuvant chemotherapy in patients with colorectal cancer liver metastases has expanded over the last 10 years. Evolution of various therapeutic modalities has occurred in the setting of an evolving and more frequent use of hepatic metastasectomy. It is clear that achieving a state of potential “resectability” is the only opportunity to obtain a cure and/or significantly extend life. Compelling evidence now exists that a neoadjuvant approach should be standard for select patients with so-called “borderline resectable” lesions. In addition, patients with initially resectable liver metastases may achieve further survival benefit from the addition of neoadjuvant treatment, with the subset of patients that obtain a complete pathologic response benefitting the most. Future neoadjuvant randomized controlled trials may further elucidate patients that will benefit from these therapeutic strategies.
The regulation of HIV-1 gene expression: the emerging role of chromatin.

Host and viral factors that regulate the expression of the human immunodeficiency virus type 1 (HIV-1) 5′ long terminal repeat (LTR) promoter have been studied since the recognition that HIV is the...
Crystal structure of the koh-amylose complex

Abstract The crystal structure of potassium hydroxide complexed amylose, obtained by heterogeneous deacetylation of amylose triacetate, has been determined through a combined stereochemical structure-refinement and X-ray diffraction-analysis. The structure crystallizes in an orthorhombic unit-cell with parameters a  8.84, b  12.31, and c (fiber repeat)  22.41 A, and with P212121 symmetry. The conformation of the amylose chain is a distorted, left-handed helix with 6 d -glucose residues per turn. Each three-residue asymmetric unit is complexed with one molecule of potassium hydroxide and three molecules of water. The K+ ion coordinates with four oxygen atoms of the amylose chain and with two other oxygen atoms, and this coordination is probably the cause for the more-extended amylose chain-conformation than would be predicted from a φ, ψ map. The distortions in the chain are primarily manifested by different O-6 rotations and by slightly different bridge and φ, ψ angles for the individual residues. The structure is extensively hydrogen bonded, although largely through water molecules, which accounts for its ready water solubility. The left-handed conformation of the chain in this structure is consistent with the conformations of amylose triacetate and V-amylose, both of which are left-handed.
An Optimization Regularization Method for Determination of Partial Structure Factors from Small-Angle Scattering Experiments

A new method is introduced for extracting partial structure factors from scattering data. For a bimodal mixture of colloidal particles, a minimum of three contrast-variation scattering experiments are necessary to determine the three partial structure factors. This determination of partial structure factors is a classically ill-posed matrix inversion. In addition to the random measurement error, there is random concentration error present in the set of scattering experiments, and composition parameters must be optimally chosen to minimize their effect on the inversion. The standard methods of least squares and regularization have been applied to the inversion, but are unable to provide physically significant solutions. Partial structure factors derived from the optimization regularization technique developed here satisfy the smoothness and physical constraints that partial structure factors must obey. This technique is effective in extracting partial structure factors from data with hard-sphere and sticky-hard-sphere interactions that contain concentration errors and wavelength-smearing effects.