cssi/SciSciGPT-SciSciNet huggingface dataset:
Visualization of the three-dimensional distribution of collagen fibrils over preovulatory follicles in the hamster.

Before an oocyte can escape from a preovulatory follicle, the apical wall must thin to the point of rupture. Although numerous layers of cells are present, it is the collagen fibrils in the theca externa that provide most of the strength to the developing follicle. The three-dimensional distribution and integrity of these fibrils over a follicle cannot be appreciated with standard used methods such as examination of thin sections by transmission electron microscopy. In this paper we describe a technique that removes cells superficial to the collagen fibrils so that their distribution may be examined by scanning electron microscopy. On the third day of the hamster's 4-day estrous cycle, bundles of fibrils pass from intrafollicular areas and ascend follicles. Approximately halfway up the follicle wall, the bundles fan out and form a meshwork of fibrils which covers the apex. As the time of ovulation approaches, the number of layers of fibrils decreases over the apex until a tear forms in the weakened matrix. Experimental results demonstrating that the meshwork is composed of collagen fibrils are presented. The usefulness of this technique in visualizing the collagen content in preovulatory follicles is discussed as well as factors that may aid in weakening this layer so that follicle rupture may occur.
Quantum electrodynamics based on self-fields: On the origin of thermal radiation detected by an accelerating observer.

We continue with our series of papers concerning a self-field approach to quantum electrodynamics that is not second quantized. We use the theory here to show that a detector with a uniform acceleration {ital a} will respond to its own self-field as if immersed in a thermal photon bath at temperature {ital T}{sub {ital a}}={h bar}a/2{pi}kc. This is the celebrated Unruh effect, and it is closely related to the emission of Hawking radiation from the event horizon of a black hole. Our approach is novel in that the radiation field is classical and not quantized; the vacuum field being identically zero with no zero-point energy. From our point of view, all radiative effects are accounted for when the self-field of the detector, and not the hypothetical zero-point field of the vacuum, acts back on the detector in a quantum-electrodynamic analog of the classical phenomenon of radiation reaction. When the detector is accelerating, its transformed self-field induces a different back reaction than when it is moving inertially. This process gives rise to the appearance of a photon bath, but the photons are not real in the sense that the space surrounding the accelerating detector is truly empty of radiation, a factmore » that is verified by the null response of an inertially moving detector in the same vicinity. The thermal photons are in this sense fictitious, and they have no independent existence outside the detector.« less
Incorporating Video Games into Physical Education.

(2007). Incorporating Video Games into Physical Education. Journal of Physical Education, Recreation & Dance: Vol. 78, No. 3, pp. 18-24.
Ambulatory electrocardiographic recordings at the time of fatal cardiac arrest.

Abstract The relation between arrhythmias at cardiac arrest and the outcome of arrest is poorly understood. The Holter monitor tracings of 13 patients were reviewed after they sustained an in-hospital cardiac arrest during ambulatory electrocardiographic monitoring. All had a prior cardiac arrest or cardiac syncope. Twelve patients had ventricular tachycardia (VT) as their initial arrest arrhythmia and 1 patient had bradycardia followed by ventricular fibrillation (VF). VT degenerated to VF in 10 of 12 patients after a mean interval of 96 ± 31 seconds (± standard error of the mean). The number of VT runs increased significantly during the hour immediately preceding arrest (p = 0.004). Despite prompt resuscitation efforts in 12 patients, only 6 survived. The 6 survivors and 6 nonsurvivors were not different with regard to age, ejection fraction, extent of coronary artery narrowing and time to first defibrillation. However, degeneration to VF within 30 seconds of arrest (5 of 6 nonsurvivors and 1 of 6 survivors, p = 0.04) and a slower rate of VT at the onset of arrest (166 beats/min in nonsurvivors and 227 beats/min in survivors, p = 0.02) were associated with unsuccessful resuscitation.
Two stage laser stabilization using external cavities: Application to a 10 μm CO 2 laser locked to an OsO 4 transition

A cw carbon dioxide laser, operating on the 10 μm R(0) transition (28.832 THz), was stabilized by locking its frequency to an evacuated Fabry–Perot cavity. The Fabry–Perot cavity was in turn stabilized to the saturated absorption resonance of the Q(15) line of 188OsO4 , contained in a second Fabry–Perot cavity. Cesium-clock referenced, frequency chain measurements of the resultant line frequency are presented together with detailed studies of the line shift sensitivities to various operating parameters.
The combined influence of trematode parasites and predatory salamanders on wood frog (Rana sylvatica) tadpoles.

Predators can have important impacts on host–parasite dynamics. For many directly transmitted parasites, predators can reduce transmission by removing the most heavily infected individuals from the population. Less is known about how predators might influence parasite dynamics in systems where the parasite relies on vectors or multiple host species to complete their life cycles. Digenetic trematodes are parasitic flatworms with complex life cycles typically involving three host species. They are common parasites in freshwater systems containing aquatic snails, which serve as obligate first intermediate hosts, and multiple trematode species use amphibians as second intermediate hosts. We experimentally examined the impact of predatory salamanders (Ambystoma jeffersonianum) and trematode parasites (Echinostoma trivolvis and Ribeiroia ondatrae) on short-term survival of wood frog tadpoles (Rana sylvatica) in 150-L outdoor pools. Two trematode species were used in experiments because field surveys indicated the presence of both species at our primary study site. Parasites and predators both significantly reduced tadpole survival in outdoor pools; after 6 days, tadpole survival was reduced from 100% in control pools to a mean of 46% in pools containing just parasites and a mean of 49% in pools containing just predators. In pools containing both infected snails and predators, tadpole survival was further reduced to a mean of 5%, a clear risk-enhancement or synergism. These dramatic results suggest that predators may alter transmission dynamics of trematodes in natural systems, and that a complete understanding of host–parasite interactions requires studying these interactions within the ecological framework of community interactions.
The Determination of Mercury in Small Terrestrial and Nonterrestrial Rock Samples by Atomic-Absorption Spectroscopy, and the Study of Mercury Release at Elevated Temperatures

An atomic-absorption method was developed for determining subnanogram amounts of mercury in 100 mg of samples and for studying the release of mercury at elevated temperatures. The rock samples were contained in a sidearm of a quartz cell, and the mercury released by heating was determined by measuring the absorption of 2537-A light passed through the cell. For a number of terrestrial and nonterrestrial samples analyzed, the results obtained agreed within a factor of 2 with neutron activation methods. This agreement is considered satisfactory since samples are not homogeneous. For a lunar sample that contained 1.79 ppb of mercury, the precision expressed as standard error is ±0.05 ppb. The sensitivity of this method for 1% light absorption is 0.03 ng; the limit of detectability is of the order of 0.01 ng. Mercury-release patterns obtained by atomic absorption methods also were in reasonable agreement with mercury-release patterns obtained by neutron-activation methods.
Modeling Deterrence and International Crises

The continuous Prisoner's Dilemma is a reasonable model for nuclear crises (usually represented by “Chicken”), and for the arms race. This article addresses the existence of credible deterrence strategies that promote cooperation as a dynamically stable steady state. Decisions made repeatedly in time are the selection by each side of a level of hostility. Assessment of the resulting situation is represented by a utility function for each player. As the game proceeds, players are concerned with the current situation as well as with the future consequences of their present decisions. Thus each side must formulate intentions and expectations of each other's future behavior and use them to infer their own present optimal decisions. A formal concept of deterrence strategy is introduced: It promises the other side retaliation in kind to prevent any gain from aggressive play, and it inflicts increasing losses as a result of escalation. If one side adopts such a deterrence strategy, the other side cannot do bette...
Electrical Measurements of the High Speed Switching Characteristics of Micron-Scale Discrete Ferroelectric Capacitors.

Abstract A novel technique was employed to obtain electrical measurements of the high speed switching characteristics of small, discrete, SBT ferroelectric capacitors in response to applied pulses. Switching speed and polarization were directly measured as a function of applied amplitude, pulse width, rise time, and capacitor area. Two different ferroelectric film thicknesses were studied: 175 nm and 240 nm. Measurements were performed using off-wafer circuitry and applied pulses with rise times as fast as 2 ns and pulse widths as narrow as 10 ns on capacitors as small as 4 μm2. A hysteresis loop was also obtained using a 20 MHz driving signal.
Tournai and Tyranny: Imperial Kingship and Critical Humanism

Almost from the first, the reign of Henry VIII witnessed high views of kingship. Some instances in the first decade of his rule have attracted much attention, but one critical episode has been overlooked. In the course of the occupation of Tournai between 1513 and 1519, Henry developed and successfully tested a complete theory of imperial kingship, partly cast in a new language of sovereignty. Drawing in part on the French models liberally strewn about the English cultural landscape, Henry asserted all the prerogatives of a rex imperator not only against the Tournaisiens but more significantly against Leo X. This new model kingship and its implications for royal relations with the church alarmed some of Henry's agents, especially Ralph Sampson. Sampson contented himself with expostulating about the threat to his conscience to his chief, Thomas Wolsey, but others showed more alarm. One of Sampson's friends, Thomas More, a similarly junior but rising functionary, offered two meditations on the potential dangers of Henry's kingship, going much beyond the abstract admonitions against tyranny of his Latin epigrams.
Pseudospectral Legendre-based optimal computation of nonlinear constrained variational problems

It is well known that, spectrally accurate solution can be maintained if the grids on which a nonlinear physical problem is to be solved must be obtained by spectrally accurate techniques. In this paper, the pseudospectral Legendre method for general nonlinear smooth and nonsmooth constrained problems of the calculus of variations is studied. The technique is based on spectral collocation methods in which the trajectory, x(t), is approximated by the Nth degree interpolating polynomial, using Legendre-Gauss-Lobatto points as the collocation points, and Lagrange polynomials as trial functions. The integral involved in the formulation of the problem is approximated based on Legendre-Gauss-Lobatto integration rule, thereby reducing the problem to a nonlinear programming one to which existing well-developed algorithms may be applied. The method is easy to implement and yields very accurate results. Illustrative examples are included to confirm the convergence of the pseudospectral Legendre method. Moreover, a numerical experiment (on a nonsmooth problem) indicates that by applying a smoothing filter procedure to the pseudospectral Legendre approximation, one can recover the nonsmooth solution within spectral accuracy.
Does endothelial dysfunction contribute to the clinical status of patients with peripheral arterial disease

Peripheral arterial disease leads to lower extremity ischemia and limb loss, and is linked to cardiovascular events. The anatomical extent of lower extremity atherosclerosis fails to fully explain ischemic symptoms or predict the development of critical limb ischemia. Endothelial dysfunction is known to contribute to the pathogenesis and clinical expression of coronary artery disease, but the importance of endothelial dysfunction in peripheral arterial disease remains incompletely understood. Endothelial dysfunction could contribute to lower extremity ischemia by impairing blood flow responses to ischemia, collateral formation and arterial remodelling, and by promoting vasospasm, thrombosis, plaque rupture and lesion progression. There is a need for additional studies examining the contribution of endothelial dysfunction to the pathogenesis of peripheral arterial disease, and the potential role of endothelial dysfunction as a surrogate marker with utility in the management of patients.
Relaxation of photon echoes in weakly ionized noble-gas plasmas

Photon echoes generated from visible transitions in the noble gases helium, neon, and argon are observed and the collisional relaxation rates are measured. The photon echoes are excited on transitions initiating from metastable states which are populated by electron impact in an rf discharge. The photon-echo intensity is measured as a function of time after the discharge is turned off and as a function of gas pressure. The reduction of the echo intensity in these two experiments is attributed to relaxation of the metastable population in the afterglow and dephasing collisions, respectively. The dependence of the photon-echo damping time on transition wavelength and perturber gas is interpreted by means of a simple van der Waals model for the excited-atom and perturber-gas interaction.
Relapsing and remitting viral diseases of the nervous system

Abstract Virus infections can recur intermittently as is painfully appreciated by sufferers of recurrent lesions caused by the herpesvirus. The mechanisms of viral exacerbation and remission have become of interest in the neurosciences with circumstantial evidence that some role is played by viruses in multiple sclerosis. Epidemiological data indicate that multiple sclerosis results from exposure to a virus in childhood followed by a long latency period. The clinical course is typically remitting and relapsing, and the brain and spinal cord contain multifocal demyelinative lesions of different ages. Studies of slow viral infections have now provided many explanations for long incubation periods and studies of both acute and persistent viral infections have shown varied mechanisms of demyelination. Several recent studies of latent and persistent viral infections have provided thought-provoking data on episodic disease.
Childhood carcinoid tumors: the St Jude Children's Research Hospital experience.

Abstract Background/Purpose: To better characterize childhood carcinoid tumors, the authors reviewed the clinical presentation, treatment, and outcomes of pediatric patients with these rare tumors. Methods: A retrospective review was conducted of medical records and pathologic materials of all children with carcinoid tumors treated at St Jude Children's Research Hospital between December 1977 and March 1999. Results: Eight patients (median age, 12.7 years) were identified; 2 were boys, and 7 were white. Primary tumor sites were the appendix (n = 5), small intestine (n = 1), bronchus (n = 1), and 1 unknown site. In 7 cases, carcinoid tumor was not suspected at the time the tumor was identified. Seven patients had localized disease; 5 remain disease-free after complete resection, and 2, whose carcinoid tumors were identified incidentally, died of metastatic mucinous adenocarcinoma of the colon. One patient who presented with symptoms of carcinoid syndrome had metastatic disease that responded poorly to cytotoxic chemotherapy and remains alive with active disease. Conclusions: Although most pediatric carcinoid tumors arise in the appendix, these tumors also occur in other primary sites. Clinical awareness and early diagnosis are important factors in preventing morbidity and mortality. Outcomes are excellent for patients with localized disease that is completely resected, but those with metastatic disease fare poorly. New therapeutic strategies are needed for these patients. J Pediatr Surg 35:1282-1286. Copyright © 2000 by W.B. Saunders Company.
Is the Poincare group a suitable gauge group for gravity

Abstract We argue that, instead of the Poincare group, the U(1)×SU(2) group generated by the quantum numbers mass and spin is a suitable gauge group for gravity. A Yang-Mills spin 2 gauge theory of gravity is proposed.
Alterations in adolescents' sensory taste preferences during and after pregnancy

Purpose: The purpose of this study was to determine adolescents' preferences during and after pregnancy for foods that differed in fat, sugar, and salt content, components that are associated with much of the flavor in food and, hence, are related to food acceptance. Methods: Sensory taste preferences for 16 foods were assessed by 52 white adolescents during the third trimester of pregnancy and again 11–13 months postpartum. The study design was a randomized, incomplete block design. Each subject evaluated the same eight foods at each interview using a 10-cm hedonic scale, which was scored 0="dislike extremely" to 10="like extremely." Three pairs of foods differed in fat content (e.g., ice cream vs. ice milk), two pairs differed in sugar content, but neither contained a sugar substitute (e.g., peaches in heavy syrup vs. natural juices), and three pairs differed in salt content (e.g., salted vs. unsalted peanuts). Differences in preferences were determined with least-squares analysis of variance. Results: Although preferences for 13 of the 16 foods did not differ between pregnancy and postpartum assessments, whole milk, skim milk, and salted peanuts were ranked significantly higher ( p = 0.02, 0.007, and 0.05) during pregnancy. Hedonic scores were higher ( p = 0.002 and 0.005) for whole milk over skim at both assessments, but ice cream was not preferred significantly over lower-fat frozen products. During pregnancy, but not after, salted peanuts, chips, and crackers were preferred ( p = 0.0003, 0.0001, and 0.03) over the unsalted/low-salt products. Conclusions: The adolescents' increased sensory taste preferences for milk and salty snack foods during pregnancy, as well as personal taste preferences, should be recognized by clinicians, and nutrition recommendations should be individualized to enhance compliance.
U.S. state government websites demonstrate better in terms of accessibility compared to federal government and commercial websites

Abstract State government websites are a main information portal for people. The primary objective of this study is to examine 50 U.S. state government websites to evaluate the status of their accessibility in comparison with federal government and randomly selected commercial websites. The results show a significant difference among the three groups (F(2, 101) = 11.81, p
Museum fatigue: a critical review.

ABSTRACT The literature on museum fatigue is critically reviewed in terms of (a) empirical studies, (b) phenomena associated with fatigue, (c) outcome measures used, and (d) possible causes of the phenomena. The review suggests that (a) fatigue should be defined in terms of both its causes and its outcomes; (b) museum fatigue is not a simple phenomenon and to understand it we need to examine the impact of all the phenomena as well as how they interact with each other; (c) at least 2 phenomena (object competition and information overload) that have been associated with “fatigue” appear to have little to do with fatigue other than share the pattern of decreased attention; (d) the 3 measures of direct observation (percent stop, viewing time, and time samples) are not highly correlated with one another; (e) added to the confusion are methodological issues, such as confounding variables and inconsistent outcomes; and finally, (f) there is a questionable relationship between overt measures of fatigue and self-r...
Pangaean divergent margins: historical perspective

Abstract Pangaean divergent margins caused by the breakup by rifting of that supercontinent display three distinct evolutionary stages. In their youth or rift stage, divergent margins display a synsediment fault style that has considerable tectonic instability. During the mature or drift stage (seafloor spreading) continental margins are relatively stable and are dominated by thermal subsidence. These two stages (rifting and drifting) are separated in many areas by an unconformity coeval with the oldest associated oceanic crust — the breakup unconformity; in some areas the onset of seafloor spreading is marked by intense magmatic activity. Sediment facies the rifting stage range from continental clastics landward of the continental basement hinge and along the flanks of the basin to saline deposits and more open-water carbonates in the axial zone of the rift. Lithologies emplaced during the rift or mature stage of margin development range from shallow clastics/carbonates to deep-water carbonate/siliceous oozes, turbidites and contourites, some of which were deposited in an anoxic environment. Deposition then is controlled by changes in configuration of basins, changes in sea level, and plate migration through several climatic belts. During the final, or old-age, of margin development, divergence gives way to convergence. This stage, which generally terminates with continental collision, is characterized by tectonism, magmatic activity, and crustal shortening. Mesozoic divergent margins along the east-west trending former Tethys Ocean have reached this stage in their evolution.
What You Told Us About Occupational Justice

In a recent issue of Occupational Therapy in Mental Health (Vol. 24(2), 2008) readers were invited to share their thoughts on the use of the terms occupational justice and social justice. There are...
Is Career Education Really Being Taught? A Second Look

There's still a long way to go to close the gap between perceptions of employers-teachers-students and skills/abilities necessary for life and work.
Right-sided Diverticulitis Mimics Appendicitis

Abstract Background Right-sided diverticulitis is a rare source of right lower quadrant pain in Western society; however, it is quite common in Asian societies. Right-sided diverticulitis presents very similarly to appendicitis, with right lower quadrant pain, fever, nausea, and laboratory abnormalities, and is often seen in young patients. Objectives In this report, we present a case of right-sided diverticulitis. We review right-sided diverticulitis’ diagnosis and management. It is important to diagnose right-sided diverticulitis because it is a good mimic of appendicitis and ideally should be diagnosed before a patient has unnecessary surgery. Case Report A 26-year-old Asian woman presented for evaluation of right lower quadrant pain and fever. She was initially thought to have appendicitis clinically, but had right-sided diverticulitis diagnosed by computed tomography (CT) scan. She was admitted and received intravenous antibiotics and bowel rest. Her right-sided diverticulitis resolved in 3 days. Conclusions Severe right lower quadrant pain in young patients of Asian descent can be right-sided diverticulitis. Right-sided diverticulitis is a benign condition managed medically that mimics appendicitis. CT imaging seems to be the best way to avoid unnecessary surgery.
Evidence for the outward transport of norepinephrine in synaptic vesicles attached to the plasma membrane.

In a low-sodium, choline+ (Ch+) medium, rat heart slices, that were labelled in vivo with [3H]norepinephrine, exhibited a delayed, Ca2+-dependent release of radioactivity, these radioactive compounds consisted of both amines and deaminated metabolites. The Ca2+-dependent release of radioactivity was largely blocked by cocaine suggesting that the release may represent an outward transport of [3H]amines. Reserpine, which is known to inhibit binding of norepinephrine to synaptic vesicles, stimulated the release of deaminated metabolites and some amines from the slices. Cocaine increased the release of [3H]amines in monoamine oxidase inhibited, reserpinized slices in the control medium. When Ch+ -Ca2+ and reserpine stimulation were combined, the effects of Ch + -Ca2+ predominated. These effects were blocked by cocaine, which then permitted the response to reserpine to become established. The conclusion derived from the above experiments is that norepinephrine coming from synaptic vesicles brought in close proximity to the plasma membrane by a Ca2+-dependent system can be transported outwardly to the extraneuronal space by a cocaine-sensitive mechanism.
Quantitative fractography of mixed mode fracture in glass and ceramics

Abstract Many ceramic structural applications involve a combination of tensile (mode I) and shear (mode II) loading conditions. Quantitative fractography was performed on monolithic and R -curve materials. Soda-lime-silica glass was selected as the monolithic material. A mica glass ceramic was selected to represent R -curve materials. Mixed-mode fracture surfaces in both materials were characterized by an absence of the mist region. For the mica glass ceramic, crack-to-mirror size ratios were found to be a function of the crack length and mode mixity. Hackle markings on mixed-mode fracture surfaces appear as lances and differ from those observed on surfaces failed in pure Mode I. Atomic force microscopy showed that the features in different regions on the mixed-mode fracture surfaces are similar and differ only by scale. The practical implications of these observations are that forensic analyses can be used without a priori knowledge of the loading conditions.
Modeling the competing phase transition pathways in nanoscale olivine electrodes

Abstract Recent experimental developments reveal that nanoscale lithium iron phosphate (LiFePO 4 ) olivine particles exhibit very different phase transition behavior from the bulk olivine phase. A crystalline-to-amorphous phase transition has been observed in nanosized particles in competition with the equilibrium phase transition between the lithium-rich and lithium-poor olivine phases. Here we apply a diffuse-interface (phase-field) model to study the kinetics of the different phase transition pathways in nanosized LiFePO 4 particles upon delithiation. We find that the nucleation and growth kinetics of the crystalline-to-crystalline and crystalline-to-amorphous phase transformations are sensitive to the applied electrical overpotential and particle size, which collectively determine the preferred phase transition pathway. While the crystalline-to-crystalline phase transition is favored by either faster nucleation or growth kinetics at low or high overpotentials, particle amorphization dominates at intermediate overpotentials. Decreasing particle size expands the overpotential region in which amorphization is preferred. The asymmetry in the nucleation energy barriers for amorphization and recrystallization results in a phase transition hysteresis that should promote the accumulation of the amorphous phase in electrodes after repeated electrochemical cycling. The predicted overpotential- and size-dependent phase transition behavior of nanoscale LiFePO 4 particles is consistent with experimental observations.
Localization of nigrostriatal dopamine receptor subtypes and adenylate cyclase

Quantitative autoradiography using [3H]-SCH 23390, [3H]-sulpiride and [3H]-forskolin was used to assess the effects of single and combined neurotoxin lesions of the nigrostriatal pathway in the rat brain on dopamine (DA) receptor subtypes and adenylate cyclase (AC), respectively. Ibotenic acid (IA) lesions of the caudate-putamen (CPu) resulted in near total loss of both [3H]-SCH 23390 and of [3H]-forskolin binding in the ipsilateral CPu and substantia nigra reticulata (SNR). [3H]-sulpiride binding in the CPu was only partially removed by this same lesion, and nigral [3H]-sulpiride binding was virtually unchanged. 6-Hydroxydopamine (6-OHDA) and IA lesions of the substantia nigra compacta (SNC) did not affect [3H]-SCH 23390 or [3H]-forskolin binding, but largely removed [3H]-sulpiride binding in the SNC. A 6-OHDA lesion of the nigrostriatal pathway followed by an ipsilateral IA injection of the CPu failed to further reduce [3H]-sulpiride binding in the CPu. These results demonstrate that postsynaptic DA receptors in the CPu are of both the D1 and D2 variety; however, a portion of D2 receptors in the CPu may be presynaptic on afferent nerve terminals to this structure. D1 receptors in the SNR are presynaptic on striatonigral terminals, whereas the D2 receptors of the SNC are autoreceptors on nigral DA neurons. The existence of presynaptic D2 receptors on nigrostriatal DA-ergic terminals could not be confirmed by this study. Co-localization of D1 receptors and AC occurs in both the CPu and SNR.
Salient findings in the hypnosis literature: April 2002.

Abstract Four important investigations were reported during the latter part of 2001. All address the biological impact of hypnotic interventions. Three of these studies focus specifically on if and how hypnotic interventions affect immune functions. A range of immune assays is employed, from allergic response to blood-based assays of immune functioning during nonlaboratory periods of stress. In all 3 cases, measurable shifts in immune functioning are associated with hypnotic interventions. A 4th compares the pattern of event-related brain potentials (ERPs) associated with hypnotic analgesia interventions and standard distraction protocols during exposure to pain.
Determination of crop-specific parameters used in foliar mass to area conversion: I. For selected varieties of grapes.

Over the years several authors have developed (Gunther et aL 1973; Gunther et aL 1974; Westlake et al. 1973) and consolidated (Iwata et aL 1977) a technique for quantifying the levels of pesticide available on treated foliage. Their efforts have provided a common methodology for more consistent residue data that can be used by diverse groups to more effectively evaluate hazards that workers encounter in treated crops. The technique developed by these authors involves a standard procedure for extracting residues from the rinsate after the foliage sample has been agitated in a surfactant solution. The amount of foliar pesticide residues recovered from this analytical procedure is commonly referred to as dislodgeable foliar residues (DFR), normally expressed in units of pesticide per unit area of leaf surface. This quantity is now of increasing interest largely because of the later development of several mathematical models that can quantitatively relate field reentry exposure to foliar pesticide dislodgeables (Popendorf and Leftingwell 1982; Nigg et aL 1984; Zweig et aL 1984; Zweig et aL 1985). The practical significance of this quantitative correlation is increased by recent amendments to a state regulation that permit California growers to collect their own residue data in support of a shorter reentry interval for methomyl on grapes (California Department of Food and Agriculture 1989).
Mitochondrial dynamics in Alzheimer's disease: opportunities for future treatment strategies.

The complexities that underlie the cognitive impairment and neurodegeneration characteristic of Alzheimer’s disease (AD) have yet to be completely understood, although many factors in disease pathogenesis have been identified. Particularly important in disease development seem to be mitochondrial disturbances. As pivotal role players in cellular metabolism, mitochondria are pertinent to cell survival and thus any deviation from their operation is certainly fatal. In this review, we describe how the dynamic balance of mitochondrial fission and fusion in particular is a necessary aspect of cell proliferation and that, as the cell ages, such balance is inevitably compromised to yield a destructive environment in which the cell cannot exist. Evidence for such disturbance is abundant in AD. Specifically, the dynamic balance of fission and fusion in AD is greatly shifted toward fission, and, as a result, affected neurons contain abnormal mitochondria that are unable to meet the metabolic demands of the cell. Moreover, mitochondrial distribution in AD cells is perinuclear, with few metabolic organelles in the distal processes, where they are normally distributed in healthy cells and are needed for exocytosis, ion channel pumps, synaptic function and other activities. AD neurons are thus characterized by increases in reactive oxidative species and decreases in metabolic capability, and, notably, these changes are evident very early in AD progression. We therefore believe that oxidative stress and altered mitochondrial dynamics contribute to the precipitation of AD pathology and thus cognitive decline. These implications provide a window for therapeutic intervention (i.e. mitochondrial protection) that has the potential to significantly deter AD progression if adequately developed. Current treatment strategies under investigation are described in this review.
Interface stoichiometry control in ZnO/Cu 2 O photovoltaic devices

Cu2O is a potential earth-abundant alternative to established thin photovoltaic materials (CIGS, CdTe, etc.) because of its low cost, high availability, and inexpensive processing, but Cu2O has seen limited development as a photovoltaic device material owing to challenges in measurement and control of interface stoichiometry and doping. We report measurements of Cu2O interface stoichiometry and the effect of interface composition on heterojunction device performance. ZnO/Cu2O interface stoichiometry was varied by adjusting the ZnO window layer deposition conditions and stoichiometry was measured by X-ray photoelectron spectroscopy. Current-voltage characteristics of ZnO/Cu2O heterojunctions indicate open circuit voltages of Voc ~ 530 mV for devices where the Cu2O layer is stoichiometric at the interface and Voc ~ 100 mV for devices where Cu2O is nonstoichiometric at the interface.
An acetaldehyde dehydrogenase from germinating seeds.

An acetaldehyde dehydrogenase from germinating peanut cotyledons has been purified and its properties have been studied. At the highest purification achieved the preparation is free of alcohol dehydrogenase activity.The enzyme is specific toward diphosphopyridine nucleotide, and can oxidize a variety of aldehydes. The highest reaction rate is obtained with acetaldehyde, which is oxidized to acetate. All the attempts to demonstrate the formation of an energy-rich acetyl derivative during the course of the reaction failed. The enzyme is inhibited by aldol; it is sensitive toward sulfhydryl reagents, including arsenite. Reduced glutathione stabilizes the enzyme, while cysteine, mercaptoethanol, and coenzyme A are inhibitory.Acetaldehyde dehydrogenase is activated by phosphate and inhibited by fatty acyl-CoA derivatives. It appears to be activated by the substrate, as was deduced from the shape of the plot of reaction velocity against acetaldehyde. These properties suggest that the enzyme is an allosteric protein.The plot of reaction velocity against substrate concentration is anomalous. The shape of this plot seems to reflect the presence of 2 different enzymatic activities, one with extremely high apparent affinity for acetaldehyde. The 2 activities may reflect 2 conformational states of a single enzyme or 2 separate enzymes.Experiments with tissue slices indicate that the reaction catalyzed by this enzyme is a step in the oxidation of ethanol to acetyl-CoA. This enzyme may also participate in the oxidation of pyruvate to acetyl-CoA in certain tissues.
An analytical framework for estimating the urban effect on climate

The surface energy budget has been used to illustrate the influence of urban landscape on both global and regional climate. This was done using empirical as well as remotely sensed data of components of the surface energy equation. At the global scale, the urban land cover has the least impact on the sensible and latent heat fluxes compared to the other land cover types. Replacing the urban land cover with vegetation did not result in a significant change to the proportionate values of the turbulent fluxes originally due to vegetation. The least impact of current urbanization on the global climate in terms of radiation and surface fluxes is because the urban land cover has the smallest fraction of all the land cover types. The relative importance of the urban landscape at the regional scale was illustrated using the example of Chester County and surroundings near Philadelphia, Pennsylvania, in the USA. The urban effect becomes more important as the fraction of urban land cover to the total increases. This is illustrated by computing turbulent fluxes for 1987, 1988, 1991, 1993 and 1996 over the Chester County area. Urbanization in Chester County and surrounding areas increased from 11% in 1987 to 19% in 1996. In 1996, urban land cover produced the largest proportionate sensible (21.4 Wm−2) and latent (14.2 Wm−2) heat fluxes during winter. During the 1996 summer, urban and vegetation land cover produced the largest proportionate sensible heat (59.2 Wm−2) while urban land cover produced the second largest proportionate latent heat flux (39.5 Wm−2). The implications of this simple analytical study point to the need to account for the urban landscape particularly in regional studies. Copyright © 2009 Royal Meteorological Society
Testosterone Stimulates the Primary to Secondary Follicle Transition in Bovine Follicles in Vitro

The mechanisms controlling the initiation and early stages of follicular growth are poorly understood. Our laboratory developed a serum-free culture system that supports spontaneous and wholesale activation of primordial follicles in pieces of cortex dissected from the ovaries of fetal calves and fetal baboons. However, very few follicles activated in vitro progressed to the secondary stage. To determine whether androgens can promote the primary to secondary follicle transition, pieces of fetal bovine ovarian cortex were cultured in serum-free medium in the absence or presence of testosterone (T, 10(-7) and 10(-6) M) or estradiol (E(2), 10(-6) M) for 10 days. Cortical pieces were then fixed and embedded in plastic for serial sectioning and morphometric analysis; fresh cortical pieces fixed on Day 0 served as uncultured controls. Freshly isolated cortical pieces contained mostly primordial follicles, whereas after 10 days in vitro, most primordial follicles had activated, differentiating into primary follicles as expected. Neither T nor E(2) affected the number of primordial and primary follicles compared with controls (P > 0.05). However, T (10(-7) and 10(-6) M) increased the number of secondary follicles (P < 0.05), whereas E(2) had no effect, suggesting that the effect of T was not due to conversion of T to E(2). In the second experiment, the optimal concentration of T for preantral follicle growth was determined. A range of lower doses of T (10(-10)-10(-7) M) increased the number of secondary follicles in cultured cortical pieces in a dose-dependent manner, with 10(-7) M T being the most effective (P < 0.05). In the third experiment, addition of a specific androgen receptor blocker, flutamide, inhibited the stimulatory effects of T on the primary to secondary follicle transition (P < 0.05), suggesting a receptor-mediated action of T. Localization of androgen receptors by immunohistochemistry revealed immunostaining for the androgen receptor in ovarian stromal cells and increasing immunoreactivity in follicle cells as follicular development progressed from primordial and primary to secondary to antral follicles, suggesting the involvement of the androgen receptor in bovine folliculogenesis. In summary, our results show that T promotes the growth of bovine follicles activated in vitro and suggest that its stimulatory effect is mediated through androgen receptors in the stroma and/or follicular cells.
Infrared Spectra of Zn and Cd Hydride Molecules and Solids

Laser-ablated Zn and Cd atoms react with molecular hydrogens upon condensation at 4.5 K to form the metal dihydride molecules in solid hydrogen and neon. Ultraviolet irradiation increases these absorptions by an order of magnitude. Natural zinc- and cadmium isotopic splittings are resolved in solid p-H2, o-D2, and HD. Weaker absorptions are assigned to the linear HMMH molecules and to metal cluster monohydrides with the assistance of DFT calculations. Upon sublimation of the hydrogen or neon matrix, the metal dihydride molecules polymerize into solid hydrides with broad absorption bands characteristic of hydrogen-bridge bonding.
Interactions among human T cell subsets.

TB and TT interactions involved in the regulation of human B cell differentiation were studied in vitro. The strategy employed here involved the isolation of OKT4+ and OKT8+ subsets and subsequent quantitative assessment of their effects on pokeweed mitogen (PWM) driven B cell differentiation as measured by the reverse hemolytic plaque assay. Thus, graded numbers of either untreated or irradiated OKT4+ and OKT8+ cell subsets were added to autologous B cells and after 6 days, cultures were assayed for plaque forming cells (PFC) activity. We found that the helper activity which is exclusively contained within the OKT4+ population is radiosensitive. Radioresistant OKT4+ helper cells could also be demonstrated but only at high T/B ratios. In contrast, the OKT8+ population is depleted of helper function and contains radiosensitive cells important in the suppression of B cell differentiation. However, the suppression observed with radiosensitive OKT8+ cells requires the presence of radiosensitive OKT4+ cells. Cooperative interactions between these subsets were further analyzed by investigating the immunoregulatory function of OKT4+ and OKT8+ cells in the induction of helper factor production in response to alloantigens. Evidence was obtained that the production of mixed lymphocyte culture (MLC) derived helper factor is dependent on OKT4+ cells but not OKT8+ cells. Furthermore, the alloantigen induced helper factor production and/or release was found to be suppressed by the radiosensitive OKT8+ subset. Finally, additional studies demonstrated that alloreactive as well as trinitrophenyl (TNP) altered-self reactive cytotoxic T lymphocytes (CTL) precursors are contained within the OKT8+ T cell subset. However, the killer cell activity was amplified by the presence of OKT4+ cells. This amplifying effect is mediated by factors released by OKT4+ cells after specific interaction with either soluble or alloantigens. These data, taken together, underscore the importance of functional TT interactions in the immunoregulation of both T and B cell differentiation.
Isotopic steam investigations of hematite (Fe2O3) for chemical looping combustion of methane

Abstract The effect of steam on the chemical looping combustion of methane over hematite (Fe2O3) is studied by the isotopic exchange method coupled with mass spectroscopy. Traditional steam was replaced with deuterium-oxide providing interesting mechanistic information not previously reported. The rapid kinetics of steam reforming were established before complete combustion reaction, and adsorption of deuterium into the iron structure was observed. Additionally, the presence of deuterium-oxide drastically reduced the combustion conversion of methane to carbon dioxide.
17O NMR spectroscopy of heterocycles. Steric effects for N-oxides

The 17O chemical shift data for a series of 2- and 4-alkyi- and -aryl-substituted pyridine N-oxides, as well as those for quinoline N-oxide (13), benzo[f]quinoline N-oxide (14) and benzo [h]quinoline N-oxide (15) at natural abundance were measured in acctonitrile at 75°C. 2-Alkyl groups cause a deshielding effect on the N-oxide chemical shifts compared with those of the 4-alkyl isomers. The largest effects are noted for 2-tert-butylpyridine N-oxide (8) and 2,6-dimethylpyridine N-oxide (12). Similarly, the 17 O chemical shift of 15 is deshielded by 18 ppm compared with that of 13 and 14. 17O chemical shift data were obtained for 2-and 4-tert-butylanisoles and compared with those of 8 and 4-tert-butylpyridine N-oxide (9). The sensitivity of the N-oxide 17O chemical shifts was substantially greater than that for the anisoles, an effect that was also observed in an analysis of the 13CNMR data of the tert-butyl groups of 8 and 9. Steric inhibition of resonance is noted for 3-methyl-4-nitropyridine N-oxide; the N-oxide 17O signal was shielded and the NO217O signal was deshielded relative to those for 4-nitropyridine N-oxide.
Lymphangioma presenting as a small renal mass during childhood.

Renal lymphangioma is a very rare lesion. A case of lymphangioma that presented as a small, hypercechoic renal mass on sonography in a child is reported. On CT, the lesion appeared as a low-density, enhancing renal mass. Despite its rarity, lymphangioma should be considered in the differential diagnosis of such a lesion. A suspected lymphangioma may be evaluated by percutaneous biopsy.
A Spectrally Efficient Frequency Hopping Scheme

Frequency hopping systems have been widely used in military communications to prevent hostile jamming, interception and detection. In traditional frequency hopping (FH) systems, hopping frequency selection at the transmitter end is controlled by a pseudo-random code sequence, and the receiver operates accordingly in exact synchronization with the transmitters hopping pattern. In an effort to meet the ever increasing requirement on information capacity and reduce the burden of synchronization, in this paper, an innovative message-driven frequency hopping (MDFH) system is proposed. By embedding part of information into the process of hopping frequency selection, the spectral efficiency of the FH system can be significantly improved. Quantitative analysis on the proposed scheme is presented to demonstrate its superior performance and enhanced security features.
Pretreatment strategy with adenosine A2A receptor agonist attenuates reperfusion injury in a preclinical porcine lung transplantation model.

Objective Adenosine A 2A receptor activation after lung transplantation attenuates ischemia–reperfusion injury by reducing inflammation. However, the effect of adenosine A 2A receptor activation in donor lungs before transplant remains ill defined. This study compares the efficacy of 3 different treatment strategies for adenosine A 2A receptor agonist in a clinically relevant porcine lung transplantation model. Methods Mature porcine lungs underwent 6 hours of cold ischemia before allotransplantation and 4 hours of reperfusion. Five groups (n = 6/group) were evaluated on the basis of treatment with ATL-1223, a selective adenosine A 2A receptor agonist: thoracotomy alone (sham), transplant alone (ischemia–reperfusion), donor pretreatment via ATL-1223 bolus (ATL-D), recipient treatment via ATL-1223 infusion (ATL-R), and a combination of both ATL-1223 treatments (ATL-D/R). Lung function and injury were compared. Results Blood oxygenation was significantly higher among ATL-D, ATL-R, and ATL-D/R groups versus ischemia–reperfusion (392.0 ± 52.5, 428.9 ± 25.5, and 509.4 ± 25.1 vs 77.2 ± 17.0 mm Hg, respectively, P P P P > .05). Conclusions Pretreatment of donor lungs with ATL-1223 was as efficacious as other treatment strategies in protecting against ischemia–reperfusion injury. If necessary, supplemental treatment of recipients with ATL-1223 may provide additional protection. These results support the development of pharmacologic A 2A R agonists for use in human clinical trials for lung transplantation.