cssi/SciSciGPT-SciSciNet huggingface dataset:
Stability and Diversity at Three Trophic Levels in Terrestrial Successional Ecosystems

An ecosystem perturbation experiment in which inorganic fertilizer was added to two successional old fields of different ages indicated that stability, expressed as resistance to modification by enrichment, increased during succession only at the primary trophic level. The perturbation was propagated throughout the arthropod herbivores and carnivores. Both herbivores and carnivores were less stable in the older field. In contrast to current ecological theory, greater diversity at a trophic level was accompanied by lower stability at the next higher level.
Bis(alkyne)cycloheptadienyl and Bis(alkyne)σ,η3-cycloheptenediyl Complexes of Tungsten

The syntheses of several new bis(alkyne)(carbonyl)(η5-cycloheptadienyl)tungsten(II) and bis(alkyne)(carbonyl)(σ,η3-cycloheptenediyl)tungsten(II) complexes are described. Addition of HBF4·Et2O to [(...
The catalytic heat exchanger using catalytic fin tubes

Abstract The characteristics of a catalytic heat exchanger which integrates heat generation and heat exchange into one equipment have been investigated by the experiment and numerical simulation. The surface of the fin tubes was catalyzed by the formation of the oxide layer and the subsequent washcoating of ZrO2, followed by the impregnation of Pd catalyst. The experimental results showed that the performance of catalytic combustion in the catalytic heat exchanger was more significantly affected by the inlet velocity of the mixture than by its inlet temperature and equivalence ratio. It was also found that the catalytic surface area was a critical parameter to obtain the complete conversion of the mixture. Numerical simulation has been performed with a commercial software FLUENT. The calculated results indicated that the performance of the catalytic combustion was influenced by the catalytic fin configuration as well as the flow pattern of the mixture over the catalytic fins. The results recommend that the number and thickness of catalytic fins should be designed above 6 pieces/inch and less than 1.0 mm to achieve the best performance in the catalytic heat exchanger.
The Natural Controlled Experiment in Organizational Research

The purpose of this paper is to delineate a research design-the natural controlled experiment - which offers a promising alternative in studying structure, process and change in social organizations. As the label - "natural controlled experiment" - implies, this design permits evaluations of causal relationships under controlled conditions, in a setting perceived as phenomenologically real (natural by the participants). In one sense this design may be conceptualized as combining some attributes of laboratory experiments and of field experiments of social organizations.
When the Lights Went Out (Nye, D.; 2010) [Book Review]

David Nye's newest book, When the Lights Went Out, is an examination of how the role of blackouts in America has evolved from a minor inconvenience to a potential terrorist plot. He contends that blackouts are a "break in the flow of social time" that reveal fundamental truths about the socioeconomic climate and the role of electricity in our lives. However, his concluding chapter on voluntary "greenouts" feels half-hearted without a discussion of technology-focused initiatives such as smart grid to improve grid reliability and encourage efficiency.
Comparison of intravenous and intranasal heroin self-administration by morphine-maintained humans.

Eight heroin-dependent individuals, maintained on divided daily doses of oral morphine, participated in a 2.5-week inpatient study comparing the effects of intranasal (IN) (placebo, 12.5, 25, 50, 100 mg) and intravenous (IV) (placebo, 6.25, 12.5, 25, 50 mg) heroin. Each morning, participants received $20 and a sample dose of heroin, and each afternoon they had the opportunity to self-administer all or part of the morning heroin dose or money amount. Participants responded under a modified progressive-ratio schedule (PR 50, 100, 200, 400, 800, 1200, 1600, 2000, 2400, 2800) during a ten-trial self-administration task. During each trial, participants could respond for 1/10th of the heroin dose or 1/10th of the money amount. The total amount of heroin and/or money chosen during the self-administration task was given at the end of the task. Thus, participants received drug and/or money twice each day: once during the morning sample session and once during the afternoon self-administration session. Participants received IV solution and IN powder simultaneously during each dosing; only one route contained active drug. Heroin produced dose-related increases in break point values by both routes of administration. Although IV heroin was approximately four-fold more potent than IN heroin, the maximal break point values for both routes were not significantly different. A similar difference in potency between the IV and IN routes was found for several ratings of subjective effects (e.g., “I feel a good drug effect,”“I feel high”), but maximal subjective ratings were lower for IN compared to IV heroin. These results suggest that the reinforcing efficacy of heroin is similar by the two routes of administration, but that IN heroin is less potent than IV heroin. The results also underscore the importance of evaluating drug self-administration in the evaluation of the abuse liability of drugs.
Demonstration of an integrated watershed assessment using a three-tiered assessment framework

Watersheds are useful templates for wetland protection and land use planning because they integrate cumulative effects that better inform site-specific management decisions. The goal of this study was to demonstrate application of a three-tiered assessment paradigm in the San Gabriel watershed (Los Angeles County, California) that incorporates monitoring at varying spatial scales and intensities. Data on wetland extent and distribution, habitat condition using rapid assessment, and intensive site monitoring were used to show how different levels of assessment can be used together to provide a deeper contextual understanding of overall wetland condition. Wetland sites in the less developed portions of the watershed were of higher overall condition compared to sites located in the more urbanized portions of the watershed. GIS analysis revealed that percent impervious surface is a useful landscape-scale indicator of riverine wetland condition. Furthermore, rapid assessment metrics were significantly correlated with stressors found at sites. Significant correlations also existed between riverine habitat condition, water chemistry, and benthic macroinvertebrate communities across streams in this watershed. This study highlights the following key concepts: (1) application of a multiple indicator approach at different spatial scales and sampling intensities promotes a better understanding of the causal relationships between land use, wetland condition, and anthropogenic stress, (2) a multi-tiered monitoring approach can provide a cost-effective means of integrating wetland status and trends assessments into routine watershed monitoring programs, and (3) a three tiered approach to monitoring provides wetland managers with an effective organizational tool that can be used to prioritize management activities.
A Hybrid Multicast Routing for Large Scale Sensor Networks with Holes

In this article, we present RE $^2$ MR, the first hybrid multicast routing protocol that builds on the strengths of existing topology-based, hierarchical and geographic multicast solutions, while addressing their limitations. In RE $^2$ MR, the multicast path search problem is formulated as the capacitated concentrator location problem (CCLP) which yields the network topology that minimizes the sum of path lengths from the multicast root to multicast members. Furthermore, its trajectory-based lightweight hole detection (THLD) discovers deployment area irregularities (i.e., network holes) that affect its solution and autonomously take them into account to generate updated routing paths, and its Energy-efficient Packet Forwarding (EPF) and Multi-level Facility Computation (MFC) reduce computational and communication overheads. We implement RE $^2$ MR in TinyOS and evaluate it extensively using TOSSIM for relatively large-scale simulations (400 nodes); we also implement RE $^2$ MR on real-hardware and perform experiments on a testbed consisting of 42 TelosB motes. Through the simulations and experiments on real-hardware, we demonstrate that RE $^2$ MR reduces the energy consumption by up to 57 percent and the end-to-end delay by up to 8 percent, when compared with the state-of-the-art multicast routing protocols.
Controlling quantum dynamics phenomena

Since the initial development of lasers in the 1960's, a longstanding dream has been to utilize these special intense radiation (light) sources to redirect the outcome of chemical reactions. In the ensuing years, much effort has gone into attempts at making this dream a reality. Emerging recent successful experiments derive from a confluence of ultrafast laser technology, control theory concepts, and suitable pattern recognition algorithms all drawn together to form adaptive machines. The adaptive machines are being used to manipulate chemical bonds, as well as a broad variety of other atomic and molecular dynamics phenomenon. These advances rest on the ability to delicately shape laser pulses so that they act as a special type of photonic reagents.
STUDIES IN STEROID METABOLISM. IX. THE EXCRETION OF PREGNANE-3α, 17α, 20α-TRIOL DURING PREGNANCY*

ABSTRACT Evidence is presented that certain enzyme preparations are unable to hydrolyze pregnane-3α,17α,20α-triol, although they readily cleave pregnane-3α,20α,diol. Comparison of enzymatic hydrolysis with mineral acid hydrolysis showed that the latter caused conversion of pregnanetriol to a substance with chromatographic properties similar to those of pregnanediol, resulting in interference with the assay of pregnanediol. The excretion of pregnanetriol during pregnancy (7 cases) showed two major peaks—in the first and third trimesters. Between these peaks there was complete disappearance of pregnanetriol from the urine at about the twelfth week. This suggests that the site of production of pregnanetriol precursors had shifted from the ovary and possibly the adrenal cortex to the placenta.
A Cost-Effective Model of Consultation-Liaison Psychiatry

Consultation-liaison psychiatry reduces the length of stay of hospitalized patients and facilitates treatment of a wide variety of psychiatric syndromes. Although consultationliaison psychiatry services now exist in virtually all academic departments of psychiatry, less than 1 percent of patients in general hospitals receive psychiatric consultations, primarily because of limited direct reimbursement (1). This paper describes a consultation-liaison service that derives significant reimbursement for time spent in patient care and earns even greater indirect revenues for the sponsoring hospital. Total reimbursement exceeds the cost of providing services, and the service is almost certainly cost-effective, two important considerations in an era of growing cost constraints (2,3).
Peripheral blood mononuclear cells from patients with bullous pemphigoid have an increased frequency of response to synthetic peptides encoded by BPAG1

Abstract We determined the response of peripheral blood mononuclear cells from patients with bullous pemphigoid and normal subjects to synthetic peptides encoded by BPAG1. Peripheral blood mononuclear cells from patients and normal subjects were cocultured in the presence of 15–22-aminoacid-long amphipathic and hydrophilic peptides selected from the BPAG1 sequence. Seven of 10 patients (70%) with bullous pemphigoid had an increased response of peripheral blood mononuclear cells (>3.25/10 6 cells) when cultured with amphipathic sequences encoded by BPAG1 compared to 3 of 10 (30%) normal subjects. Peripheral blood mononuclear cells from 3 of 15 (20%) patients and 3 of 15 normal subjects (20%) demonstrated an increased response when cultured with hydrophilic peptides. Peptides associated with an increased peripheral blood mononuclear cell response in patients with bullous pemphigoid were adjacent to regions of BPAG1 recently demonstrated to contain epitopes recognized by circulating autoantibodies in the sera of patients with bullous pemphigoid. Increased peripheral blood mononuclear cell responses were more commonly observed in patients with bullous pemphigoid with generalized disease and those who had their disease for longer than 2 months (p
Numerical investigation of the slope discontinuities in large deformation finite element formulations

In many multibody system applications, the system components are made of structural elements that can have different orientations, leading to slope discontinuities. In this paper, a numerical investigation of a new procedure that can be used to model structures with slope discontinuities in the finite element absolute nodal coordinate formulation (ANCF) is presented. This procedure can be applied to model slope discontinuities in the case of commutative rotations of gradient deficient elements that are used for modeling thin beam and plate structures. An important special case to which the proposed procedure can be applied is the case of all planar gradient deficient ANCF finite elements. The use of the proposed method leads to a constant orthogonal element transformation that describes an arbitrary initial configuration. As a consequence, one obtains, in the case of large commutative rotations and large deformations, a constant mass matrix for structures which have complex geometry. The procedure used in this investigation to model slope discontinuities requires the use of the concept of the intermediate finite element coordinate system. For each finite element, a new set of gradient coordinates that define, at the discontinuity node, the element deformation with respect to the intermediate element coordinate system is introduced. These new gradient coordinates are assumed to be equal for the two finite elements at the point of intersection. That is, the change of the gradients of two elements at the intersection point from their respective intermediate initial reference configuration is assumed to be the same. This procedure leads to a set of linear algebraic equations that define the orthogonal transformation matrix for the finite element. Numerical examples are presented in order to demonstrate the use of the proposed procedure for modeling slope discontinuities.
Learning Design Sketching from Animations and Storyboards

A digital pen-and-paper system that generates stroke-by-stroke animations was used to compare the perception of interactive animations versus printed storyboards. Design students studied a space-planning example as either an animation or a storyboard and then emulated the example in doing a similar problem. Students viewing the animations rather than the storyboards performed marginally better in terms of matching the example steps and meeting design quality criteria. Students may understand the process of design sketching, but may lack the skills to copy the steps. Emulating the solution requires both cognitive skills and graphic facility. While beginners could logically organize spatial adjacencies, they often radically resized required program areas to streamline geometry. After organizing building spaces, they lacked the graphic conventions to articulate architectural features, so they could not copy refinement steps. Subjects at all levels used approximately the same number of strokes, with more prod...
Childhood and adolescent psychosis: a review of the past 10 years.

ABSTRACT Objective Developmental aspects of psychosis are reviewed and related to the more frequent psychotic conditions in children and adolescents. Method The review of the recent literature focuses on developmental aspects of psychotic phenomena, i.e., hallucinations, delusions, and thought disorder. Results While the applicability of much early work on this topic is limited, more recent work suggests that psychotic conditions are observed in childhood and increase in frequency during adolescence. Conclusions Developmental factors in the expression of psychosis are relevant to the diagnosis and treatment of such conditions.
Hybrid TiO 2 nanoparticles: an approach for developing site specific DNA cleavage

We have developed hybrid light responsive TiO2 nanoparticles electronically linked to PNA oligonucleotides that site specifically bind to double stranded target DNA. This opens a new opportunity for the development of a highly efficient "artificial restriction enzyme" whose activity can be controlled by using light. The work focuses on the use of TiO2 nanocomposites as analogs of restriction enzymes with unique specificity that does not exist in current biological approaches. TiO2 nanoparticles electronically linked to DNA or PNA adapters have been site-specifically attached along double stranded λ DNA vectors. Illumination of this assembly results in selective oxidation of DNA at the deepest "thermodynamic traps" located closest to the nanoparticle surface, causing DNA cleavage. We investigate the effect of the sequence and length of DNA and PNA adapters on the specificity of DNA cleavage. Related to this issue, the potential use of TiO2/DNA nanocomposites as "rare cutters" that cleave DNA in the places not achieved with existing protein-based enzymes is investigated.
Cross sections for the dissociative attachment of electrons to NO

Cross sections for the production of O(-) by electron attachment to NO are reported. It is found that the maximum value of the cross section is about 52 percent higher than the measurement of Rapp and Briglia (1965). Cross sections for the process of polar dissociation, e + NO yields N(+) + O(_), have also been measured, and the threshold energy for this process has been obtained.
Knowledge management – systems implementation: lessons from the silicon valley

Hind Benbya (editor) Published by Chandos Publishing, Oxford, 2008, 288+xxx pp ISBN: 1-84334-266-9, price £39.95.The book entitled Knowledge Management – Systems Implementation: Lessons from the Si...
Gender-Specific Normative Perceptions of Alcohol-Related Protective Behavioral Strategies

The present research aimed (a) to determine whether students underestimate gender-specific descriptive normative perceptions for protective behavioral strategies; (b) to evaluate the relationships among perceived gender-specific descriptive and injunctive drinking norms and perceived gender-specific descriptive norms for protective behavioral strategies; and (c) to examine whether normative perceptions for protective behavioral strategies relate to use of these strategies when controlling for relevant drinking behavior factors (i.e., alcohol consumption, negative consequences, and attitude toward drinking behavior) and social norms factors (i.e., perceived descriptive and injunctive norms). Students (N = 666; 56.6% men) completed measures assessing drinking behavior and attitudes toward drinking, perceived descriptive and injunctive norms, perceived protective behavioral strategies, and protective behavioral strategies. Findings demonstrated that students consistently underestimated the use of strategies for the typical male student, whereas results were less consistent for the typical female student. In addition, results indicated that same-sex normative perceptions for protective behavioral strategies were associated with personal use of these strategies, even when controlling for relevant drinking behavior and social norms factors. Results stress the importance of evaluating factors that are associated with use of protective behavioral strategies. Implications for social norms preventative interventions are discussed.
An assay for betaine-homocysteine methyltransferase activity based on the microbiological detection of methionine

Abstract Betaine-homocysteine methyltransferase (BHMT: EC 2.1.1.5) catalyzes a methyl transfer from betaine to homocysteine (Hcy) forming dimethylglycine and methionine (Met), respectively. We have developed an assay for BHMT activity based on the microbiological detection of one of its products, Met. The microbiological assay uses Escherichia coli J5-3, a Met auxotroph. When cultured in minimal media, J5-3 growth increases linearly with Met supplementation up to 50 μM (2.24 μg/mL). Although not sensitive enough for kinetic analyses, this assay is adequate for measuring activity levels in crude or purified enzyme preparations using saturating substrate concentrations. When BHMT activity was measured in crude liver extracts, using both the radioactive and microbiological assays, the values obtained show a high degree of correlation ( r 2 > 0.93) over an eight-fold range of activities. We have used the microbiological assay to identify stachydrine as a naturally occurring methyl donor substrate for BHMT. The sensitivity of detecting BHMT activity by the microbiological assay for Met can be increased at least an order of magnitude by using dimethylacetothetin, a sulfonium analog of betaine, as the methyl donor substrate.
Finite element analysis of composite plates using a weak form of the Kirchhoff constraints

Abstract A six-node triangular C0 plate element is developed using the assumed strain method. A weak form of the Kirchhoff constraints is used to define the assumed shear strain field. The element so developed is free of shear locking and performs well even when the element boundaries are curved. It is demonstrated that the element provides satisfactory results in the analysis of various composite plates.
Endoscopic dacryocystorhinostomy in patients taking aspirin perioperatively.

Abstract Purpose The aim of this study is to report the results of endoscopic dacryocystorhinotomy (EDCR) in patients who did not interrupt their low-dose (75–150 mg daily) aspirin regimen for the procedure. Materials and methods A case note review was made of all 40 patients taking aspirin who had EDCR at Ipswich Hospital from May 1998 to October 2003. Age, gender, indications for surgery, complications, and outcome were analyzed and the bleeding rate compared to that in patients who were not on aspirin or warfarin who had an EDCR. Results Of the 51 EDCRs performed in the 40 patients, 47 had complete relief of epiphora. Two of the patients with a persistent watering eye are to have revision surgery, 1 patient was observed (75% improvement), and 1 patient has since died. A total of 33 patients had no postoperative complications; 5 had epistaxis but only 1 of these required a nasal pack; 1 each had minor periorbital bruising, confusion, and facial pain, none of which delayed discharge. None required readmission. Of 257 EDCRs in patients not on aspirin or warfarin, 1.3% had epistaxis resulting in delayed discharged or readmission. Conclusions EDCR is a safe and efficacious treatment in patients with distal nasolacrimal obstruction in patients taking aspirin and does not require stopping the aspirin perioperatively.
Mitochondrial RNA from cultured animal cells. Distinctive high-molecular-weight and 4 s species

Abstract Mitochondria were purified by differential and isopycnic centrifugation from cultures of hamster (BHK-21) cells that had been labeled for prolonged periods with radioactive RNA precursors, either during exponential growth or during treatment with a level of actinomycin (0.1 μg/ml.) that preferentially suppresses cytoplasmic ribosomal RNA synthesis. The mitochondrion-associated RNA was then characterized as to sedimentation properties, major and minor nucleotide composition, behavior on acrylamide gels, and sensitivity to rifampicin, actinomycin D and ribonuclease. The results indicated that the RNA consisted of three main classes. 1. (1) Cytoplasmic ribosomal RNA, presumably arising from cytoplasmic ribosomes present in the mitochondrial fraction; 2. (2) An “actinomycin-resistant” high-molecular-weight RNA fraction, that sedimented slightly behind cytoplasmic 18 s RNA on conventional density gradient centrifugation, and whose synthesis was resistant to 0.1 μg/ml. of actinomycin; and 3. (3) A slowly sedimenting (4 s) fraction. The actinomycin-resistant high-molecular-weight mitochondrial RNA was virtually unmethylated, had a low G+C content (38%), and was separable into two components either by prolonged centrifugation or by acrylamide gel electrophoresis; it was sensitive to ribonuclease, and its synthesis resembled cellular, rather than microbial or viral, RNA in sensitivity to rifampicin and to a high level of actinomycin. The mitochondrial 4 s RNA fraction had an electrophoretic mobility similar to that of cytoplasmic transfer RNA, but was only half as heavily methylated as the latter and also differed substantially in major and minor nucleotide patterns.
Point-charge calculation of quadrupolar parameters for bridging oxygen sites in vitreous silica: Structural implications

The quadrupolar coupling constant Cq and the asymmetry parameter $\ensuremath{\eta}$ for the bridging oxygen sites in vitreous silica structures derived via classical molecular dynamics simulation have been calculated using the point-charge lattice summation method. The results of these calculations indicate that while Cq is a function of both the Si-O-Si angle and the associated Si-O distances, $\ensuremath{\eta}$ depends only on the Si-O-Si angle. The analytical forms of these functional dependences are found to be similar to those reported in previous studies based on ab initio calculations on small clusters. However, the magnitude of Cq is found to decrease with increasing Si-O distance in contrast with a reverse trend obtained in previous ab initio calculations on small clusters. The present results, when combined with the previously reported $^{17}\mathrm{O}$ nuclear magnetic resonance spectroscopic results for bridging oxygen sites in vitreous silica, imply a strong negative correlation between Si-O bond lengths and Si-O-Si bond angles in the glass structure. Such a negative correlation is consistent with the anomalous density variation in silica as well as with energetic considerations.
Mass transfer studies of a Kiil haemodialyser.

This paper determines the worth, through comparison with experimental data, of a mathematical model of a flat-plate, countercurrent-flow dialyser. The model assumes a distributed mass transfer resistance on the blood side, a simple permeability for the membrane, and a lumped resistance on the dialysate side of the dialyser. The model agrees within 6 per cent when compared to experimental data. Mass transfer and ultrafiltration data are reported for the Kiil dialyser.
Mitochondrial amplification selectively increases doxorubicin sensitivity in breast cancer cells with acquired antiestrogen resistance

The metabolic phenotype of cancer, characterized by uncoupled mitochondrial respiration and increased mitochondrial oxidative stress, is an attractive pharmacological target for sensitizing cancer cells to therapies that rely on oxidative stress for their tumor specific cytotoxicity. The identification of specific cancer sub-types for which metabolic priming of tumors prior to chemotherapy is beneficial is critical, particularly in heterogeneous diseases such as breast cancer. The effects of the thiazolidinedione drug troglitazone were examined in normal mammary epithelial cells and cancer cell lines representing three clinically relevant breast cancer phenotypes. Endpoints measured were PGC1α mRNA expression, proliferation, cell cycle phase distribution, mitochondrial capacity and superoxide generation, and sensitivity to the chemotherapy drug doxorubicin. Troglitazone increases expression of PGC1α, a key mediator of mitochondrial biogenesis, in normal mammary epithelial cells and in breast cancer cell lines. The induction of PGC1α mRNA is at least partially dependent on PPARγ activation. In estrogen receptor negative cells and cells with acquired antiestrogen resistance, troglitazone treatment increased mitochondrial superoxide production and mitochondrial capacity. At pharmacologically achievable doses, troglitazone pretreatment significantly enhanced the sensitivity of cancer cells to the chemotherapy agent doxorubicin. This effect was most dramatic in estrogen receptor positive cells with acquired antiestrogen resistance, in which troglitazone and doxorubicin combined had superadditive effects compared to treatment with either agent alone. In contrast, troglitazone treatment did not appreciably sensitize non-malignant mammary epithelial cells to doxorubicin induced cytotoxicity, despite increasing PGC1α mRNA. These data suggest that troglitazone or a similarly acting compound could be used to selectively prime tumor cells to the cytotoxic effects of anticancer agents such as doxorubicin and ionizing radiation. This novel treatment strategy may be most effective in women with antiestrogen insensitive tumors, a patient population with historically poor response to traditional therapies.
A generalized framework for studying the vibrations of lumped parameter systems

Abstract In this short note we show that the classical approach for obtaining the governing equation for the vibration of lumped parameter systems is not sufficiently general enough to incorporate well accepted mechanisms for the dissipation and for the storage of energy that are constituents of the vibrating system. We discuss a generalization that reduces to a coupled system of differential-algebraic equations that need to be solved simultaneously. We show that the generalization allows us to study vibrating systems wherein one has an implicit relationship between the relevant forces and kinematical quantities with regard to the mechanisms for the storage and the dissipation of energy.
Armed/Disarmed Effects and Adamantyl Expansion of Some Caged Tricyclic Acetals en Route to Tetrodotoxin1,2

Transformation of the previously prepared tricyclic ketone 4 into an advanced intermediate, 2a, of the Kishi−Goto synthesis of tetrodotoxin requires, among other things, cleavage of the internal acetal. In our attempts to carry this out, we were confronted by two major obstacles, one resulting from armed/disarmed effects encountered during acid-catalyzed acetolyses. Thus ester protecting groups proximal to the acetal moiety inhibited cleavage, e.g., 4 → 8a and 7 → 8b. Although the corresponding ether analogs 9a and 9b did undergo acetolysis, the products obtained, 10a and 10b, respectively, revealed the second obstacle, namely the proclivity of the caged systems to undergo adamantyl expansion. The latter result was found to depend upon the presence of properly positioned nucleophilic substituents. Thus 11b underwent adamantyl expansion to 12b but its C7 epimer 15 experienced facile cleavage to bicyclic product 16. As an alternative to solvolysis for cleavage of the internal acetal, reductive elimination w...
Synthesis of polymers with amino end groups by atom transfer radical polymerization

Atom Transfer Radical Polymerization (ATRP) is a controlled radical polymerization process that produces polymers with predictable molecular weights, narrow polydispersities, and well-defined halogen end groups. The key factor in the control of the polymerization process is the presence of a metal/ligand complex that provides a fast, reversible activation and deactivation of the growing polymer chains. The ligands, used to complex the metal are mostly tertiary amino compounds. However, amines can interact with the halogen end groups of the initiator molecules or of the growing chains. Our investigations concern-ing this issue indicate that under the experimental conditions used during the polymerization process, interactions of end groups with tertiary amines are negligible. Ammonia and primary amines, e.g., n-butylamine, however can react with the halogen end groups. Moreover, after the polymerization reaction they can be used as nucleophilic agents to replace the halogens by other functional end groups....
A general growth model for mark-recapture data

Abstract The general four-parameter size-age growth model of Schnute incorporates many classical formulations, such as the von Bertalanffy, Gompertz, and Richards, as submodels. The general model has different submodels depending on the values of two model parameters a and b. We develop here the equivalent model representations for mark-recapture data, consisting of size measurements at the times of marking and recapture and the times at large. The general mark-recapture model for these data contains only three distinct parameters, because actual fish age is not included in the data set. Thus, mark-recapture data can be used to determine a general growth model only if one of the parameters, most likely size at the starting age, is specified beforehand. The model is applied to two data sets with both size-age and mark-recapture data: Arctic char in the Wood River system, Alaska and rainbow trout in the Kenai River, Alaska. Different growth formulations are isolated for the two data sets, illustrating the versatility of Schnute's formalism of growth. In only one instance is the ubiquitous von Bertalanffy growth model selected, suggesting that alternative growth models should be considered more frequently. We discuss how growth variations of individuals may be incorporated into the general model.
Progression from meiosis I to meiosis II in Xenopus oocytes requires de novo translation of the mosxe protooncogene.

Abstract The meiotic maturation of Xenopus oocytes exhibits an early requirement for expression of the mosxe protooncogene. The mosxe protein has also been shown to be a component of cytostatic factor (CSF), which is responsible for arrest at metaphase of meiosis II. In this study, we have assayed the appearance of CSF activity in oocytes induced to mature either by progesterone treatment or by overexpression of mosxe. Progesterone-stimulated oocytes did not exhibit CSF activity until 30-60 min after germinal vesicle breakdown (GVBD). Both the appearance of CSF activity and the progression from meiosis I to meiosis II were inhibited by microinjection of mosxe antisense oligonucleotides just prior to GVBD. These results demonstrate a translational requirement for mosxe, which is temporally distinct from the requirement for mosxe expression at the onset of meiotic maturation. In contrast to progesterone-treated oocytes, oocytes that were induced to mature by overexpression of mosxe exhibited CSF activity at least 3 hr prior to GVBD. Despite the early appearance of CSF, these oocytes were not arrested at meiosis I. These results indicate that, although CSF activity is capable of stabilizing maturation-promoting factor (MPF) at meiosis II and in cleaving embryos, it is incapable of stabilizing MPF prior to or at meiosis I. These studies show that the complex regulation of the cell cycle during meiosis differs significantly from the regulation of the cell cycle during mitosis.
The influence of convection electric fields on thermal proton outflow from the ionosphere

The continuity, momentum and energy hydrodynamic equations for an O(+)-H(+) ionosphere have been solved self-consistently for steady state conditions when a perpendicular (convection) electric field is present. Comparison of the H(+) temperature profiles obtained with and without the electric field show that the effect of the electric field is to enhance the H(+) temperature at high altitudes from about 3600 to 6400 K. Due to ion heating by the electric field, there is a net reduction of O(+) in the F2-region as compared with the case of a nonconvecting ionosphere. When the reduction of O(+) is neglected, the electric field acts to increase the H(+) outward flux. However, when the reduction of O(+) is included, there is a net reduction in the outward H(+) flux. Nevertheless, the convection electric field still results in an increase in the rate of depletion of the F-region ionization due to H(+) outflow, by a factor of 2.2 for a 100 mV/m electric field.
Optimal interdiction of a supply network

Under certain conditions, the re-supply capability of a combatant force may be limited by the characteristics of the transportation network over which supplies must flow. Interdiction by an opposing force may be used to reduce the capacity of that network. The effects of such efforts vary for differing missions and targets. With only a limited total budget available, the interdictor must decide which targets to hit, and with how much effort. An algorithm is presented for determining the optimum interdiction plan for minimizing network flow capacity when the minimum capacity on an arc is positive and the cost of interdiction is a linear function of arc capacity reduction.
A reinvestigation of the kinetic parameters of phosphoenolpyruvate carboxykinase

Abstract A new assay for phosphoenolpyruvate carboxykinase has been devised whose sensitivity is sufficient to detect the formation by crude hepatic extracts of 1 × 10−11 moles of phosphoenolpyruvate. By the utilization of this assay it has been determined that the apparent Km of oxaloacetate is in the range of 1 to 5 × 10−6 M for the hepatic enzymes from rat and guinea pig. These values are approximately two orders of magnitude lower than all previous data and indicate that the enzyme is sensitive to modulations of oxaloacetate concentrations that occur physiologically.
Neurotoxic amino acids in human degenerative disorders

Abstract A critical issue in clinical neurosciences concerns the mechanisms responsible for the selective neuronal degeneration that occurs in a number of hereditary disorders including Huntington's disease, Alzheimer's dementia and the various spinocerebellar degenerations. Although the modes of genetic transmission vary for these disorders, two peculiar features link them together. First, neuronal degeneration begins after a period of normal differentiation and function, often becoming manifest in mid- or late-life. Secondly, select populations of neurons are affected, whereas related and even contiguous neuronal systems are spared. One hypothesis to explain selective neuronal degeneration, which has attracted increasing attention over the last decade, implicates the neurotoxic effects of the acidic neuroexcitatory amino acids.
Further studies by the angiostomy method of hormonal secretion of pancreas and suprarenal.

These experiments are concerned with the study of the effect of the administration of various substances upon the function of the pancreas and the adrenal.The method employed consisted of the use of an angiostomy cannula implanted on the superior pancreatico-duodenal vein and the suprarenal vein. The use of this cannula had already been recorded.Procedure. Three control samples of blood were drawn from the angiostomized vessels and from the femoral artery. 0.2 cc. of each sample of blood were then injected intraperitoneally into three white mice. This was followed by the injection of the materials studied into the femoral vein of a dog. At varying intervals after the intravenous injection, blood was again drawn from the three vessels and injected intraperitoneally into a new series of white mice. These mice were subsequently killed two hours later by decapitation and their blood sugar determined by the Hagedorn-Jensen method. The secretion of epinephrin and insulin was interpreted by the effect upon the b...
Phosphate transfer enzymes in cartilage

An enzymically stable powder prepared from embryonic chick cartilage has permitted demonstration and partial purification of pyruvate kinase and adenylate kinase for the first time in cartilage. Pyruvate kinase from cartilage catalyzes synthesis of UTP, a process of potential usefulness to mucopolysaccharide synthesis. It has also been possible to conclusively demonstrate the presence of glucose-6-phosphatase in several fractions of cartilage extract, including one rich in matrix mucopolysaccharide. Un enzymaticamente stabile pulvere, preparate ab cartilagine de embryones de gallina, ha permittite pro le prime vice le demonstration e le purification partial de cinase de pyruvato e de cinase de adenylato in cartilagine. Cinase de pyruvato ab cartilagine age como catalysta in le synthese de triphosphato de uridina, un processo de utilitate potential in le synthese de mucopolysaccharido. Esseva etiam possibile demonstrar definitivemente le presentia de glucosa-6-phosphatase in plure fractiones de extracto de cartilagine, incluse un que esseva ric in mucopolysaccharido de matrice.
The scientific and practical importance of trace elements

E. J. Underwood's discovery of the essentiality of cobalt for ruminant animals is the classic example of the vast benefits to agricultural production of research into the nutritional significance of trace elements. The extension of this discovery, culminating in the identification of vitamin B $_{12}$ , resulted in similar benefits for human health, notably the conquest of pernicious anaemia. Since then, additional essential trace elements have been discovered. Deficiency or imbalance, whether occurring naturally or from human activities, has been shown to present significant problems for the health of man and animals. Essentiality has been proved for a rapidly growing range of 'new' trace elements, whose biochemical mechanisms of action and implications for human health are unknown. In spite of an increasing knowledge of significant changes in the exposure of man and animals to trace elements from diet and environment, the concern of nutrition policy planners for inorganic micro-nutrients remains overshadowed by that for the bulk components of the diet. The application of existing knowledge of trace element nutrition to problems of human and animal health will depend on a clear understanding of events that link molecular, biochemical mechanisms to the clinical manifestation of deficiencies.
Radiation enhancement by 9-aminocamptothecin: the effect of fractionation and timing of administration.

Abstract Purpose: The camptothecins (CPTs) are potent radiation sensitizers in vivo but the optimal schedule of administration is unknown. In this article, the effects of irradiation combined with 9-aminocamptothecin (9AC) on a mouse mammary cancer and the gastrointestinal tract were compared for single and fractionated treatment. We also examined the circadian dependency for cytotoxicity, radiation sensitization, and acute toxicity after single doses of 9AC given at six different times over 24 h. Materials and Methods: 9AC was administered intramuscularly to C3Hf/Kam mice with and without an 8 mm mouse mammary carcinoma (MCa-4). Acute toxicity was assessed by examination of body weight loss, peripheral blood counts, clinical assessment of diarrhea, and survival. Radiation sensitization was assessed using the tumor regrowth delay model. Results: Regrowth delay of MCa-4 tumor after a single treatment of 15 Gy is comparable to 28 Gy given in 14 fractions (absolute regrowth delays of 7.1 days and 6.6 days, respectively). With 9AC alone, comparable tumor regrowth was obtained with a total dose of 4 mg/kg given intramuscularly repeated twice weekly (1 mg/kg doses X 4), or as a single injection of 4 mg/kg (2.9 days and 3.8 days, respectively). 9-AC and irradiation together in single doses of 15 Gy and 4 mg/kg resulted in little radiation sensitization compared to the repeated 9AC schedule combined with fractionated irradiation [Dose Modifying Factors (DMF) of 1.12 vs. 2.8, respectively]. Acute normal tissue toxicity after single or fractionated 9AC treatment was assessed at six times over a 24-h period (6 a.m. , 10 a.m. , 2 p.m. , 6 p.m. , 10 p.m. , and 2 a.m. ) and was highest at 2 a.m. after either single or multiple doses. A single dose of 9AC administered with single fraction irradiation could be escalated by 33% when given at the best-tolerated time. Conclusion: The frequency and timing of CPT administration with irradiation are important factors to be considered in the design of clinical protocols. CPTs are S-phase inhibitors that are better tolerated by the mouse when given during the rest phase when intestinal mucosal proliferation is relatively low. A modest increase in CPT dosage was possible by choosing the best tolerated time to administer the radiation sensitizer. This concept could potentially be evaluated in clinical trials with this class of agents.
Bioactives in Blueberries Improve Insulin Sensitivity in Obese, Insulin-Resistant Men and Women

Dietary supplementation with whole blueberries in a preclinical study resulted in a reduction in glucose concentrations over time. We sought to evaluate the effect of daily dietary supplementation with bioactives from blueberries on whole-body insulin sensitivity in men and women. A double-blinded, randomized, and placebo-controlled clinical study design was used. After screening to resolve study eligibility, baseline (wk 0) insulin sensitivity was measured on 32 obese, nondiabetic, and insulin-resistant subjects using a high-dose hyperinsulinemic-euglycemic clamp (insulin infusion of 120 mU(861 pmol)⋅m(-2)⋅min(-1)). Serum inflammatory biomarkers and adiposity were measured at baseline. At the end of the study, insulin sensitivity, inflammatory biomarkers, and adiposity were reassessed. Participants were randomized to consume either a smoothie containing 22.5 g blueberry bioactives (blueberry group, n = 15) or a smoothie of equal nutritional value without added blueberry bioactives (placebo group, n = 17) twice daily for 6 wk. Both groups were instructed to maintain their body weight by reducing ad libitum intake by an amount equal to the energy intake of the smoothies. Participants' body weights were evaluated weekly and 3-d food records were collected at baseline, the middle, and end of the study. The mean change in insulin sensitivity improved more in the blueberry group (1.7 ± 0.5 mg⋅kg FFM(-1)⋅min(-1)) than in the placebo group (0.4 ± 0.4 mg⋅kg FFM(-1)⋅min(-1)) (P = 0.04). Insulin sensitivity was enhanced in the blueberry group at the end of the study without significant changes in adiposity, energy intake, and inflammatory biomarkers. In conclusion, daily dietary supplementation with bioactives from whole blueberries improved insulin sensitivity in obese, nondiabetic, and insulin-resistant participants.
Developing criteria for determining corrective action thresholds during reliability verification testing (RVT)

A formula for the expected number of corrective actions during reliability demonstration testing is derived. It is assumed that modes fail independently, each mode fails as a homogeneous Poisson process, and the distribution of modes is Pareto. Given these assumptions, the distribution of the time to corrective action is derived for a single mode. These mode results are then combined to obtain system results. An approximation is made at the system level to obtain useful results. >
Molybdenum in the diet: an estimate of average daily intake in the United States

Previous studies have estimated the average intake of molybdenum (Mo) from the diet at approximately 300 to 400 micrograms/day. Foods collected in a grocery basket sampling program were analyzed for Mo content. The Mo concentration of these foods was combined with published United States Department of Agriculture estimates of food consumption to estimate the average daily dietary intake of Mo in the United States. This estimate is less than those previously reported and varies between 120 and 240 micrograms Mo/day, depending on age, sex, and income.