cssi/SciSciGPT-SciSciNet huggingface dataset:
Observations on applications of importance sampling in structural reliability analysis

Abstract Monte Carlo with Importance Sampling (MCIS) has been used to both evaluate the failure probability and search for the dominant failure modes of the system. Information generated from other schemes such as the First- and Second-Order Reliability Methods, and knowledge of the dominant modes, has been used to construct effective sampling densities to estimate failure probabilities. The implications of this information are discussed. In a system problem, a stratified density was used. Such a density tends to bound the weights and hence not cause the variance of the estimator to diverge. Also, the informationsused implies the knowledge of the unimportant random variables. The lack of this knowledge can lead to bad estimates. The use of the estimated coefficient of variation (COV) of the estimator is discussed. The estimated COV arising from densities contructed with the previously mentioned information tends to be small, i.e., the estimator is accurate. However, the COV can be misleading. In the second application, it is shown easily that MCIS can give erroneous answers.
26S Proteasome regulation of Ankrd1/CARP in adult rat ventricular myocytes and human microvascular endothelial cells

Ankyrin repeat domain 1 protein (Ankrd1), also known as cardiac ankyrin repeat protein (CARP), increases dramatically after tissue injury, and its overexpression improves aspects of wound healing. Reports that Ankrd1/CARP protein stability may affect cardiovascular organization, together with our findings that the protein is crucial to stability of the cardiomyocyte sarcomere and increased in wound healing, led us to compare the contribution of Ankrd1/CARP stability to its abundance. We found that the 26S proteasome is the dominant regulator of Ankrd1/CARP degradation, and that Ankrd1/CARP half-life is significantly longer in cardiomyocytes (h) than endothelial cells (min). In addition, higher endothelial cell density decreased the abundance of the protein without affecting steady state mRNA levels. Taken together, our data and that of others indicate that Ankrd1/CARP is highly regulated at multiple levels of its expression. The striking difference in protein half-life between a muscle and a non-muscle cell type suggests that post-translational proteolysis is correlated with the predominantly structural versus regulatory role of the protein in the two cell types.
Are there Differences in Typing Performance and Typing Forces between Short and Long travel Keyboards

With keyboards gravitating towards thinner designs (shorter key travel distances) it is important to understand how these short travel keyboards may affect typing performance, typing forces and operator comfort. Using 15 subjects (7 males, 8 females), we wanted to determine whether there were differences in typing performance when computer operators typed on three keyboards with the same activation force (0.6 N) but with different key travel distances (2.0mm, 2.5mm and 4.0mm). During a 15 minute typing session on each keyboard, typing performance (speed and accuracy), typing forces and perceived fatigue ratings were measured. There were no differences in typing speed (p = 0.39), typing accuracy (p = 0.33) or keystroke durations (p = 0.15) across the three keyboards. However, typing force differences were measured (p < 0.003) with the longest travel keyboard (4.0mm) having higher mean and peak forces compared to the shorter travel keyboards (2.0 and 2.5 mm). These findings indicate that there is no apparen...
Effect of Trap States on Interfacial Electron Transfer between Molecular Absorbates and Semiconductor Nanoparticles

TiO2 and ZrO2 nanocrystals synthesized by the thermal decomposition of molecular precursors in hot surfactant solvents show much improved crystallinity compared with nanoparticles prepared via hydrolysis of metal alkoxides in water (Trentler, T. J.; Denler, T. E.; Bertone, J. F.; Agrawal, A.; Colvin, V. L. J. Am. Chem. Soc. 1999, 121, 1613). In this work, we examine the effect of crystallinity and therefore the trap-state density on the dynamics of interfacial electron transfer between adsorbates and nanoparticles. Subpicosecond mid-IR and visible transient absorption spectroscopic techniques were used to study electron-injection and recombination dynamics of TiO2 and ZrO2 nanoparticles and nanocrystalline thin films sensitized with catechol and coumarin-343. Comparison of dynamics in materials with different crystallinity demonstrates that electron recombination dynamics are strongly dependent on the preparation method, and the effect on injection dynamics is significant when the injection energy level i...
Revisiting Bounded Rationality

The theory of bounded rationality harbors assumptions that lead to an understanding of human nature conflicting with observation. Arguments are presented explaining why the concept of bounded rationality will ultimately interfere with progress in cognitive science and why the concept presents an inadequate view of human nature to students of decision making.
High Content Image Analysis Identifies Novel Regulators of Synaptogenesis in a High-Throughput RNAi Screen of Primary Neurons

The formation of synapses, the specialized points of chemical communication between neurons, is a highly regulated developmental process fundamental to establishing normal brain circuitry. Perturbations of synapse formation and function causally contribute to human developmental and degenerative neuropsychiatric disorders, such as Alzheimer's disease, intellectual disability, and autism spectrum disorders. Many genes controlling synaptogenesis have been identified, but lack of facile experimental systems has made systematic discovery of regulators of synaptogenesis challenging. Thus, we created a high-throughput platform to study excitatory and inhibitory synapse development in primary neuronal cultures and used a lentiviral RNA interference library to identify novel regulators of synapse formation. This methodology is broadly applicable for high-throughput screening of genes and drugs that may rescue or improve synaptic dysfunction associated with cognitive function and neurological disorders.
Hypothermia impairs performance in the Morris water maze.

Abstract Fifteen rats were trained to learn the location of a spatially fixed platform hidden in a Morris water maze (14–16°C). Asymptotic performance was achieved over six training days (10 trials/day). Then retention of the task was assessed immediately after lowering core body temperature (T c ) to 28° or 30°C or stabilizing at 37°C (the normothermic control). The hypothermia treatment order was counterbalanced according to a Latin-square design. Hypothermia significantly impaired all measures of spatial performance. Hypothermic animals were then rewarmed in a 40°C water bath to 37°C T c and spatial performance tested again. Artificial rewarming resulted in complete recovery of all measures of spatial performance. These results demonstrate that hypothermia impairs performance in the Morris water maze, possibly by an amnesic mechanism, and that returning T c to normothermic levels initiates recovery of performance.
A high pressure thermobalance

Abstract A high pressure thermobalance was assembled by placing a DuPont Model 950 balance into a stainless steel enclosure. The thermobalance is capable of operation to a maximum pressure (of N 2 ) to 500 atm and to a maximum temperature of 500°C. Operation of the instrument is illustrated by the thermogravimetric curves of BaBr 2 ·2H 2 O, CuSO 4 ·5H 2 0 and NaHCO 3 at various pres
Is There a Role for MRI in the Preoperative Assessment of Patients With DCIS

Background Breast magnetic resonance imaging (MRI) is used to identify residual and additional disease in patients with invasive carcinoma. The use of MRI in assessing extent of disease for ductal carcinoma in situ (DCIS) is less well defined. This study assessed the value of MRI in the preoperative evaluation of DCIS.
Iterative solution of the eigenvalue problem for a dielectric waveguide

The authors present a numerical approach to the simulation of dielectric waveguides that is free of spurious modes and is based on the solution of an eigenvalue problem for the two transverse components of the magnetic field. They introduce a new discretization which has several computational advantages. In particular, by careful design of the discretization procedure, the authors obtain systems of equations for the two components which are equivalent in the sense that a rotation over 900 corresponds to a suitable permutation of indices. The eigenvalue problem is solved iteratively by using an adapted version of the Chebyshev-Arnoldi algorithm. This approach takes full advantage of the sparsity of the matrix and circumvents the large memory requirements and the large computational complexity associated with dense methods. This allows the authors to employ meshes that are sufficiently fine to resolve higher modes without large discretization errors. >
Aerosol-, but not intradermal-immunization with the live vaccine strain of Francisella tularensis protects mice against subsequent aerosol challenge with a highly virulent type A strain of the pathogen by an αβ T cell- and interferon gamma- dependent mechanism

Francisella tularensis is an extremely virulent facultative intracellular bacterial pathogen of many mammalian species including mice and humans in which it causes a spectrum of disease collectively called tularemia. In humans, intradermal or inhaled inocula of 10cfu or less of the most virulent strains of the pathogen are sufficient to cause severe infection and possible death; in mice similar inocula are routinely lethal. An attenuated live vaccine strain, F. tularensis LVS, was developed almost 50 years ago, and remains the sole prophylactic against virulent strains of the pathogen. Using F. tularensis LVS as a model vaccine, we recently showed that it was possible to systemically immunize various mouse strains and protect them against subsequent massive (2000 cfu) intradermal (i.d.) challenge, but not against low dose (approximately 10 cfu) aerosol challenge, with virulent strains of the pathogen. This is troubling because the latter route is considered an important means of deliberately disseminating F. tularensis in a bioterrorist attack. Others have previously shown that administering LVS to humans, guinea pigs and monkeys as an aerosol enhanced protection against subsequent aerosol challenge with virulent F. tularensis. In the present study, we show the same phenomenon in BALB/c and C3H/HeN mice. In this model, interferon gamma (IFNgamma) and CD4+ and CD8+ T cells are essential for the expression of anti-Francisella immunity in the lungs. Combined this immune response operates by limiting dissemination of the pathogen to susceptible internal organs. Further, understanding of how inhaled LVS elicits local cell-mediated protective immunity will be critical for devising improved vaccines against pulmonary tularemia.
Distributed radio relay for communication and control with physical-layer security in smart grid

Information security has become a prominent issue, and this is especially critical for communications in the smart grid. For wideband connections with substations or end users, short and medium range radio communication can offer great convenience and flexibility. However, compared to network security of wired networks, achieving wireless security is more difficult. In general confining a radio signal in a desired space is infeasible, thus wireless information leakage is a critical problem. Encryption and authentication based security techniques have been proved effective, but all of them need to consume additional radio resources. In this research a physical-layer security technique complementary to the security means implemented at upper layers is proposed and examined. It takes advantage of rich multipath environment to focus radio energy on some desired spatial spot, while achieving nulling at other spots. What makes spatial focusing and nulling possible is transmit waveform optimization based on propagation environments. In particular, radio relay is considered for outdoor wireless communication, not only due to its range extension ability, but its virtual radio mirror function. The use of radio relay makes a virtually rich multipath environment thus validates the proposed physical-layer security scheme. Using a matched filter receiver at test points, the optimization problem is actually the Quadratically Constrained Quadratic Program (QCQP) which is known as an NP-hard problem, thus the Semidefinite Program (SDP) as a relaxation technique is used to obtain suboptimal results. Physical-layer security in terms of channel gain discrimination is numerically validated using the IEEE802.15.4a outdoor NLOS outdoor channel model, considering worst-case (maximal) information leakage at the eavesdropping location.
Effects of volatile anesthetic on channel structure of gramicidin A.

Volatile anesthetic agent, 1-chloro-1,2,2-trifluorocyclobutane (F3), was found to alter gramicidin A channel function by enhancing Na transport (Tang et al. 1999. Biophys. J. 77:739 -746). Whether this functional change is associated with structural alternation is evaluated by circular dichroism and nuclear magnetic resonance spectroscopy. The circular dichroism and nuclear magnetic resonance results indicate that at low millimolar concentrations, 1-chloro-1,2,2-trifluorocy- clobutane causes minimal changes in gramicidin A channel structure in sodium dodecyl sulfate micelles. All hydrogen bonds between channel backbones are well maintained in the presence of 1-chloro-1,2,2-trifluorocyclobutane, and the channel structure is stable. The finding supports the notion that low affinity drugs such as volatile anesthetics and alcohols can cause significant changes in protein function without necessarily producing associated changes in protein structure. To understand the molecular mechanism of general anesthesia, it is important to recognize that in addition to structural changes, other protein properties, including dynamic characteristics of channel motions, may also be of functional significance.
Choreographing a queer ethics: Between Bill T. Jones and Keith Hennessy

What possibilities might melancholia offer for a queer ethics, and what might it mean to perform such an ethics onstage? In this essay the author analyzes mobile figurations of U.S. nationalism, violence, and visuality as theorized in the work of contemporary queer chorographers Bill T. Jones and Keith Hennessy. The author suggests that Jones's 1989 Untitled and Hennessy's 2006 Sol Niger evidence shifts in racialized sexuality and empire from the 1980s to the War on Terror, even as they both mark convergences between geopolitics and biopolitics. Reading these works together – despite their markedly different aesthetics and tones – elucidates a queer ethics rooted in and capable of contending with our contemporary political moment of war and U.S. empire building. Further, these works model how dance and other embodied, collective practices can engender what Jill Dolan calls “utopian performances” or possibilities for critique and transformation rooted in moving social bodies.
Employee appearance and the Americans with Disabilities Act: An emerging issue?

The recent passage of the Americans with Disabilities Act (ADA), considered the most far-reaching civil rights legislation since the Civil Rights Act of 1964, promises to raise demanding new challenges for employers. This article alerts readers to one example of what may prove to be a long list of unanticipated, but potentially onerous, repercussions from this legislation. Specifically discussed is the role of the ADA in the likely emergence of the issue of employee physical appearance. In addition to the role of the ADA, we explain how other legal forces, as well as organizational and economic forces, may propel physical appearances to the level of a formidable social issue.
Inertia and streamline curvature effects on peristaltic pumping

Abstract Peristaltic pumping by an infinite train of sinusoidal waves in the walls of a two-dimensional tube is investigated theoretically when the inertial and streamline-curvature effects are moderate but not negligible as it is the case for roller pumps and the gastrointestinal tract. It is found that the pumping performance increases with increasing wall curvature and is decreased by inertial effects except at high squeeze. As in the inertia-free, infinite wavelength case there is a backwards flow (reflux) near the moving walls which is enhanced by both the inertial and curvature effects. Under certain conditions, there are boluses of fluid moving at the wave speed as if they were trapped by the wave. The range of this trapping is decreased by inertial effects and increased by curvature effects.
Explicit use of the Biot coefficient in predicting shear‐wave velocity of water‐saturated sediments

Predicting the shear-wave (S-wave) velocity is important in seismic modelling, amplitude analysis with offset, and other exploration and engineering applications. Under the low-frequency approximation, the classical Biot-Gassmann theory relates the Biot coefficient to the bulk modulus of water-saturated sediments. If the Biot coefficient under in situ conditions can be estimated, the shear modulus or the S-wave velocity can be calculated. The Biot coefficient derived from the compressional-wave (P-wave) velocity of water-saturated sediments often differs from and is less than that estimated from the S-wave velocity, owing to the interactions between the pore fluid and the grain contacts. By correcting the Biot coefficients derived from P-wave velocities of water-saturated sediments measured at various differential pressures, an accurate method of predicting S-wave velocities is proposed. Numerical results indicate that the predicted S-wave velocities for consolidated and unconsolidated sediments agree well with measured velocities.
The effect of selenate, selenite, and sulfate on the growth of six unicellular marine algae

Abstract Axenic cultures of Chlorella sp., Dunaliella primolecta Butcher, Platymonas subcordiformis (Willie) Hazen, Platymonas sp., Porphyridium cruentum (Ag.) Nag., and Tetraselmis chuii Stein were grown in artificial sea water containing various concentrations of sulfate, selenate, and selenite. In the absence of selenium, most algae were sensitive to reductions in sulfate levels below those concentrations normally found in sea water. When selenium was added, low selenate (≈0.01 ppm Se) concentrations restored the rate of growth previously diminished by low sulfate concentrations, whereas high selenate concentrations (≈10 ppm Se) were lethal. No lethal effects were caused by selenite, even at concentrations as high as 100 ppm. The effects of selenite were somewhat conditioned by the sulfate concentration of the medium. Taken in toto, these experiments suggest that the effects of selenium on marine algae depend on the species of the alga, the concentration and oxidation state of the element, and the concentration of sulfate. Uptake studies indicate that selenite and selenate are incorporated into the algal cells.
ANTIGEN CAPTURE, PROCESSING, AND PRESENTATION BY DENDRITIC CELLS : RECENT CELL BIOLOGICAL STUDIES

Antigen uptake, processing and presentation by dendritic cells [DCs] have become amenable to cell biological approaches. The critical events occur in DCs that are undergoing maturation in response to inflammatory stimuli. Successful antigen presentation can be monitored directly using antibodies that are specific for particular MHC-peptide complexes. What a contrast to earlier times when it was difficult to visualize even the uptake of antigen into isolated DCs and DCs in the T cell areas of lymphoid organs! We emphasize here the efficiency of antigen capture and presentation by maturing DCs, especially for dying cells. This presentation of cellular antigens by DCs likely explains the phenomenon of cross priming in the setting of transplantation and other clinical states.
Immunology of human schistosomiasis: off the beaten path

SUMMARY Reviews of the immunology of human schistosomiasis generally address the host's protective responses against infection or the factors associated with development of severe pathology. However, there is a growing recognition that the high number of patients expressing moderate morbidity, rather than the few patients with severe morbidity, accounts for the greatest public health impact of schistosomiasis. Therefore, other aspects of the host immune response that have received relatively little attention may actually provide pivotal answers in our understanding and management of the morbidity associated with human schistosomiasis. This review highlights lines of investigation that focus on how immune responses to schistosomiasis may affect schistosomiasis-associated anaemia, alter susceptibility or disease progression during co-infections, and influence effective execution of mass treatment programmes.
Dementia Risk After Traumatic Brain Injury vs Nonbrain Trauma: The Role of Age and Severity

Importance Epidemiologic evidence regarding the importance of traumatic brain injury (TBI) as a risk factor for dementia is conflicting. Few previous studies have used patients with non-TBI trauma (NTT) as controls to investigate the influence of age and TBI severity. Objective To quantify the risk of dementia among adults with recent TBI compared with adults with NTT. Design, Setting, and Participants This retrospective cohort study was performed from January 1, 2005, through December 31, 2011 (follow-up, 5-7 years). All patients 55 years or older diagnosed as having TBI or NTT in 2005 and 2006 and who did not have baseline dementia or die during hospitalization (n = 164 661) were identified in a California statewide administrative health database of emergency department (ED) and inpatient visits. Exposures Mild vs moderate to severe TBI diagnosed by Centers for Disease Control and Prevention criteria using International Classification of Diseases, Ninth Revision ( ICD-9 )codes, and NTT, defined as fractures excluding fractures of the head and neck, diagnosed using ICD-9 codes. Main Outcomes and Measures Incident ED or inpatient diagnosis of dementia (using ICD-9 codes) 1 year or more after initial TBI or NTT. The association between TBI and risk of dementia was estimated using Cox proportional hazards models before and after adjusting for common dementia predictors and potential confounders. We also stratified by TBI severity and age category (55-64, 65-74, 75-84, and ≥85 years). Results A total of 51 799 patients with trauma (31.5%) had TBI. Of these, 4361 (8.4%) developed dementia compared with 6610 patients with NTT (5.9%) ( P P P P P P = .55; vs age 65-74: HR, 1.25; 95% CI, 1.04-1.51; P = .02; age interaction P Conclusions and Relevance Among patients evaluated in the ED or inpatient settings, those with moderate to severe TBI at 55 years or older or mild TBI at 65 years or older had an increased risk of developing dementia. Younger adults may be more resilient to the effects of recent mild TBI than older adults.
A secondary isotopic standard for 6Li/7Li determinations

A thirteen kilogram sample of highly purified Li2CO3 prepared from virgin ores has been assayed to have an absolute 6Li/7Li abundance ratio of 0.0832±0.0002. This value was determined by a mass spectrometric comparison with a primary standard blended from specially prepared, highly enriched, well-characterized isotopic materials. The abundance ratio of the primary standard was 0.083656±0.000003. The instrumental bias of the mass spectrometer was determined from isotopic ratio measurements of four primary standards having 6Li abundances in the 7–8% range.
Identification of a gonadotropin-releasing hormone-responsive region in the glycoprotein hormone alpha-subunit promoter.

Transcriptional regulation of the glycoprotein hormone alpha-subunit gene has been studied extensively in placental cells, but much less is known about its regulation in the pituitary gland. In this study, transcriptional control of the human alpha-subunit gene by GnRH was analyzed using transient expression assays in primary cultures of rat pituitary cells using alpha promoter constructs linked to a luciferase reporter gene. Deletion mutants between -846 and -156 basepairs (bp) had little effect on basal expression, but further deletion to -132 bp reduced basal activity by approximately 50%. Deletion of a cAMP response element between -132 and -99 bp caused a marked loss of basal activity, reducing expression to that of background luciferase activity. The same constructs were analyzed for cAMP responsiveness in primary pituitary cells. The degree of stimulation with 1 mM 8-bromo-cAMP (3.6- to 6.0-fold) was relatively unaffected by deletions from -846 to -132 bp, whereas cAMP stimulation was decreased by ...
Ceramic Engineering Education

Ceramic Engineering or Ceramics has existed as a separate academic discipline in the United States for over ninety years having been founded to ensure the application of the principles of chemistry to the fabrication of ceramic products. With the maturation of the traditional ceramic industries, including refractories and glass, and the growth markets of high technology ceramics for electronic and structural applications, the requirements of a ceramic engineering education are undergoing rapid change. The current status of the ceramic industry and its impact on education and the ceramic education infrastructure are reviewed. Within this framework and the property and structure emphasis unique to ceramics, a model undergraduate degree curriculum is presented.
Application of the Concept of Referenced Radio Navigation

This paper discusses referenced radio navigation, the concept whereby monitoring stations at known locations are used to calibrate out systematic errors in a navigation system. This concept is implemented by broadcasting calibration data to the navigating user for application as real-time corrections to the position fixes made by the user's basic navigation equipment. A method is suggested for the automatic transmission and receiver processing of the correction data. Referenced radio navigation overcomes many of the shortcomings generally associated with long-distance navigation systems, and can increase accuracy and repeatability significantly. The concept is particularly applicable to global navigation systems such as OMEGA, in which propagation or synchronization errors can contribute substantially to the system error budget.
Production of hypertension following choline deficiency in weanling rats.

SummaryOf 28 weanling rats surviving a 5-day choline-deficient diet and maintained on a normal diet for 6 months thereafter 20 animals or 71% had arterial blood pressure levels over 150 mg at the time of sacrifice. Similar animals receiving an 0.4 mg % or 2.0 mg % choline diet and older rats (140 g) surviving 10 days of similar diets did not have demonstrable hypertension at sacrifice 6 months later.
A light and electron microscopic study of the intraneuronal transport of horseradish peroxidase and wheat germ agglutinin-peroxidase conjugates in the rat visual system.

The ability of horseradish peroxidase (HRP) and the lectin wheat germ agglutinin (WGA) covalently conjugated with HRP to label retrogradely dorsal lateral geniculate nucleus (dLGN) neurons, subsequent to injections of either marker into rat striate cortex, was assessed by counting labelled neurons in the dLGN. Rats injected with either marker in concentrations ranging from 0.1 to 100μg/μl of HRP either free or coupled to WGA were perfused 24 h later and their brains incubated using the chromagen tetramethyl benzidine. At high concentrations (2–100μg/μ1), comparable numbers of labelled neurons were observed in the dLGN but at low concentrations (0.1–1.0μg/μ1), WGA-HRP labelled 2–5 times more dLGN neurons than did unconjugated HRP. The sugarN-acetylglucosamine, and free WGA added in excess to WGA-HRP, abolished the retrograde labelling of dLGN neurons.
Insights Into Trade Protection under U.S. Trade Remedy Laws

Abstract The U.S. managed trade policy has become increasingly controversial. In this paper, I investigate the determinants of trade remedy protection for the steel industry. A time series analysis suggests that protection is determined by both conventional economic factors and political economy factors. The empirical results offer a better insight into the origins of protective trade legislation under the U.S. trade remedy laws and have important implications for U.S. trade policy.
Alpha particle track production in polycarbonate foils amplified by electrochemical etching

Abstract We have examined two of the parameters concerned with alpha-particle track production in 250 μm thick polycarbonate foils as part of our work to find the average dose delivered to the endosteal surface of bone out to a distance of 10 μm by 239 Pu alpha particles. These parameters are (i) the efficiency of track production by α-particles from a “thin” source as a function of absorber thickness and (ii) the track diameter as a function of etching time. The efficiency was determined by varying the air pressure in our vacuum-sealed alpha-calibrator over a wide range and observing the energy degradation and number of alpha particles incident on a surface barrier detector from a 2.0 μCi 239 Pu source. The polycarbonate foils were then irradiated by α-particles at the same air densities ( T and P correction included) and using the same geometry as before; after which they were electrochemically etched. When the number of tracks vs absorber thickness was plotted, a curve showing the “Bragg-peak” resulted. The peak was approximately a factor of two above the flat portion of the curve. For the track diameter vs etching time determination, foils were irradiated by alpha-particle sources, and then electrochemically etched for times ranging from 15 min to 4 h. No tracks were observed below 30 min of etching. A plot of track diameter vs etching time for the tracks observed is presented. Two size groups, or categories, of tracks are observed on α-particle-irradiated foils after electrochemical etching. A reason for the two groups is proposed.
Pharmacological investigation of CNS unit responses in awake, freely moving animals

Knowledge of the effects of drugs on the CNS has progressed in parallel with the development of new techniques for investigating the functions of the CNS, once considered to be a relatively inaccessible organ for scientific study. One technique that has greatly enhanced our understanding of the effects of drugs on nervous tissue is the electrophysiological recording of single neurons. Single unit recordings have been utilized for several decades to examine the effects of various drugs on the CNS. However, the vast majority of these studies have employed acute animal preparations, using subjects that were anesthetized and/or paralysed. While these latter studies have greatly increased our knowledge of the effects of drugs within the CNS, it has only recently become apparent that immobilization of the animal, particularly when an anesthetic is employed, dramatically alters the response of CNS neurons to various pharmacological agents. Thus, the emergence of the technique of recording single unit activity within the CNS of awake, freely moving animals must be considered a mjor breakthrough in the study of CNS pharmacology.
A forward model of cave dripwater δ18O and application to speleothem records

Speleothem oxygen isotope records in arid regions are typically interpreted as indicators of the total precipitation amount and/or its seasonal balance. Such studies rarely address the potential influence of groundwater mixing processes on δ18O variability of cave dripwater. Here, we develop a model of oxygen isotopes in dripwater, which we compare to water and stalagmite measurements from Cave of the Bells, Arizona. We simulate moisture flux from surface to cave as a two-layer "leaky-bucket" model. In observations and the model, fed with modern climate data, dripwater δ18O is most comparable to that of winter precipitation. We show that seasonality and duration of the regional summer monsoon affect how much summer precipitation reaches the cave. We employ a Monte Carlo method to specify statistically realistic ranges for input climate variables and produce time series and variance spectra of cave drips. The spectra of our synthetic δ18O series exhibit a high degree of variance at decadal to multidecadal frequencies, despite being driven by synthetic data that includes only a seasonal cycle. This suggests that some background level of variance in speleothem δ18O records could be due to nonclimatic processes, such as subsurface water storage and mixing. Interpreting climatic vs. nonclimatic controls on speleothem δ18O variance could be achieved by replicating records from different caves.
Allosteric Networks in Thrombin

Serine proteases are found ubiquitously in both eukaryotes and prokaryotes however the dynamic motions of this largest peptidase family remains unknown. All serine proteases have a double β-barrel core surrounded by connecting loops and helices, but compared to the prototypical serine protease, chymotrypsin, thrombin has more extended loops that are thought to impart greater specificity. We analyzed apo-thrombin and active site-bound (PPACK-thrombin) using a combination of MD, accelerated MD and NMR. Community analysis of the MD ensembles identified groups of residues linked through correlated motions and physical contacts. AMD simulations, calibrated on measured residual dipolar couplings, revealed correlated loop motions connecting the active site with distal allosteric regulator binding sites. The backbone dynamics profile (from ps to ms motions) of thrombin was determined in both states using R1, R2, 15N-{1H}NOEs, TROSY Hahn-Echo, and relaxation dispersion experiments. The apo thrombin backbone is highly dynamic and shows motions across multiple time scales. The various surface loops move on different time scales. The substrate-binding loops showed intermediate time scale motions that are quenched upon PPACK binding. TROSY Hahn-echo and relaxation dispersion experiments reveal a large number of residues throughout the protein undergoing temporally correlated µs-ms motions. These include the Na+-binding loop and the β-strand connecting exosite 1 and the active site, both of which are implicated in allosteric coupling of effector binding sites with the active site. The results show a network of slowly exchanging residues extends through the entire apo-thrombin molecule.
Reversal of chronic regional myocardial dysfunction (hibernating myocardium) by synchronized diastolic coronary venous retroperfusion during coronary angioplasty.

Abstract A 62 year old man with previous myocardial infarction, an occluded right coronary artery and a 90% stenosis of the left anterior descending coronary artery underwent angioplasty with the support of coronary venous retroperfusion of arterial blood during the procedure. In two of four angioplasty balloon dilations of the left anterior descending coronary artery, synchronized diastolic retroperfusion of the coronary veins with arterial blood was applied to protect the severely dysfunctioning myocardium from additional ischemia. Two-dimensional echocardiography was used to monitor and quantitate alterations in left ventricular function. Retroperfusion of arterial blood resulted in immediate improvement in ischemic zone wall motion despite the totally occluded artery during balloon dilation. Echocardiographic images recorded after angioplasty showed a marked improvement in contraction of the previously dyskinetic segments, with changes similar to those seen during balloon dilations with synchronized diastolic coronary venous retroperfusion. Thus, in this patient, viability of chronically dysfunctioning myocardium could be demonstrated by the improvement in regional wall motion during retroperfusion. This technique could eventually be of value to elucidate the anatomic location of viable myocardium while maintaining adequate left ventricular systolic function during coronary artery interventions in the catheterization laboratory.
Germ cell-specific proteins interact with the 3' untranslated regions of Prm-1 and Prm-2 mRNA

The testis-specific mouse protamine genes (Prm-1 and Prm-2) are transcribed in haploid round spermatids, their mRNAs stored as cytoplasmic ribonucleoprotein particles and translated about 1 week later in elongating spermatids. We have compared the in vitro translational efficiencies of deproteinized Prm-1 mRNA isolated from purified populations of germ cells and found that Prm-1 mRNA from round spermatids translates as efficiently as Prm-1 mRNA from elongating spermatids, suggesting that translation of Prm-1 mRNA is normally repressed in round spermatids. Previous studies in transgenic mice have shown that the 3' UTR of Prm-1 mRNA is necessary and sufficient for its translational control (Braun et al., 1989). In this manuscript, we have used an RNA band shift assay to identify an activity, present in cytoplasmic fractions of meiotic spermatocytes and postmeiotic round spermatids, that binds the 3'UTRs of both Prm-1 and Prm-2 mRNA. We have used 3' UTR deletion variants to map the binding site to a 22-nt region within the Prm-1 3' UTR and to a 20-nt region within the Prm-2 3' UTR. uv cross-linking of the RNA band shift activities detected with the Prm-1 and Prm-2 3' UTRs generated the same two RNA/protein complexes of 53 and 55 kDa. The presence of the binding activity in the cell type and subcellular compartment associated with Prm-1 and Prm-2 mRNA storage suggest that the activity may be actively engaged in translational repression of these mRNAs.
Perceived neighborhood safety and incident mobility disability among elders: the hazards of poverty

We investigated whether lack of perceived neighborhood safety due to crime, or living in high crime neighborhoods was associated with incident mobility disability in elderly populations. We hypothesized that low-income elders and elders at retirement age (65 – 74) would be at greatest risk of mobility disability onset in the face of perceived or measured crime-related safety hazards. We conducted the study in the New Haven Established Populations for Epidemiologic Studies of the Elderly (EPESE), a longitudinal cohort study of community-dwelling elders aged 65 and older who were residents of New Haven, Connecticut in 1982. Elders were interviewed beginning in 1982 to assess mobility (ability to climb stairs and walk a half mile), perceptions of their neighborhood safety due to crime, annual household income, lifestyle characteristics (smoking, alcohol use, physical activity), and the presence of chronic co-morbid conditions. Additionally, we collected baseline data on neighborhood crime events from the New Haven Register newspaper in 1982 to measure local area crime rates at the census tract level. At baseline in 1982, 1,884 elders were without mobility disability. After 8 years of follow-up, perceiving safety hazards was associated with increased risk of mobility disability among elders at retirement age whose incomes were below the federal poverty line (HR 1.56, 95% CI 1.02 – 2.37). No effect of perceived safety hazards was found among elders at retirement age whose incomes were above the poverty line. No effect of living in neighborhoods with high crime rates (measured by newspaper reports) was found in any sub-group. Perceiving a safety hazard due to neighborhood crime was associated with increased risk of incident mobility disability among impoverished elders near retirement age. Consistent with prior literature, retirement age appears to be a vulnerable period with respect to the effect of neighborhood conditions on elder health. Community violence prevention activities should address perceived safety among vulnerable populations, such as low-income elders at retirement age, to reduce future risks of mobility disability.
Objective evaluation of expert performance during human robotic surgical procedures

Robotic laparoscopic surgery has revolutionized minimally invasive surgery and has increased in popularity due to its important benefits. However, evaluation of surgical performance during human robotic laparoscopic procedures in the operating room is very limited. We previously developed quantitative measures to assess robotic surgical proficiency. In the current study, we want to determine if training task performance is equivalent to performance during human surgical procedures performed with robotic surgery. An expert with more than 5 years of robotic laparoscopic surgical experience performed two training tasks (needle passing and suture tying) and one human laparoscopic procedure (Nissan fundoplication) using the da Vinci™ Surgical System (dVSS). Segments of the human procedure that required needle passing and suture tying were extracted. Time to task completion, distance traveled, speed, curvature, and grip force were measured at the surgical instrument tips. Single-subject analysis was used to compare training task performance and human surgical performance. Nearly all objective measures (8 out of 13) were significantly different between training task performance and human surgical performance for both the needle passing and the suture tying tasks. The surgeon moved slower, made more curved movements, and used more grip force during human surgery. Even though it appears that the surgeon performed better in the training tasks, it is likely that during human surgical procedures, the surgeon is more cautious and meticulous in the movements performed in order to prevent tissue damage or other complications. The needle passing and the suture tying training tasks may be suitable to establish a foundation of surgical skill; however, further training may be necessary to improve transfer of learning to the operating room. We recommend that more realistic training tasks be developed to better predict performance during robotic surgical procedures and testing the transferability of basic skill acquisition to surgical performance.
Evaluation of the effects of ischemic injury and ureteral obstruction on delayed graft function in cats after renal autotransplantation.

Objective— To determine the relative importance of ischemic injury to delayed graft function (DGF) in cats. Study Design— Experimental study. Animals— Six intact female cats. Methods— Cats had renal autograft transplantation without ureteral transection and reimplantation and a contralateral nephrectomy. Serum creatinine and blood urea nitrogen (BUN) concentrations were measured regularly and abdominal ultrasound was performed before surgery, the day after surgery and twice weekly thereafter. Ultrasound-guided renal biopsy was performed on day 7. Cats were euthanatized on day 21. Histology of the autograft, ureter, bladder, vascular anastomoses sites, and contralateral kidney were performed. Observations were compared with those from an historic group of research cats that had extravesicular ureteroneocystostomy and contralateral nephrectomy.1 Results— Five cats completed the study. Serum creatinine and BUN concentrations increased after surgery, peaking at 3.2±0.8 and 77.6±15.9 mg/dL, respectively, 1–2 days after surgery. Serum creatinine concentration returned to the reference interval by 6 days after surgery. BUN gradually decreased in all cats but did not return to the reference interval by study end. Serum creatinine and BUN concentrations were consistently lower but not significantly so (P=.29 and .56, respectively) compared with the historic ureteroneocystostomy group. No ultrasonographic abnormalities or renal biopsy histologic abnormalities were observed. At necropsy, 1 autograft had generalized interstitial fibrosis. Conclusion— Harvesting the renal graft and the ischemia before revascularization causes impaired renal function after engraftment. Clinical Relevance— The process of harvesting and reimplanting the renal graft can contribute to DGF in cats, independent of ureteral obstruction.
Confined states in phase dynamics: The influence of boundary conditions and transient behavior.

Confined states in phase dynamics\char21{}the coexistence of states with different wavelengths\char21{}are further studied. In particular, a stable and accurate numerical code is developed to study the dynamic equation of motion for two sets of boundary conditions\char21{}a pinned phase and an unpinned phase. With a pinned phase, stable confined states are found to exist for a wide range of parameter values. With an unpinned phase, the localized states are at best neutrally stable. Also, analytic solutions are found for the stationary confined states.
New Carbon Dioxide-Selective Membranes Based on Sulfonated Polybenzimidazole (SPBI) Copolymer Matrix for Fuel Cell Applications

Carbon dioxide-selective facilitated transport membranes containing both mobile and fixed carriers in the sulfonated polybenzimidazole copolymer matrix were successfully synthesized. Transport prop...
Cardiovascular System Effects of Marijuana

Marijuana and delta9-tetrahydrocannabinol (THC) increase heart rate, slightly increase supine blood pressure, and on occasion produce marked orthostatic hypotension. Cardiovascular effects in animals are different, with bradycardia and hypotension the most typical response. Cardiac output increases, and peripheral vascular resistance and maximum exercise performance decrease. Tolerance to most of the initial cardiovascular effects appears rapidly. With repeated exposure, supine blood pressure decreases slightly, orthostatic hypotension disappears, blood volume increases, heart rate slows, and circulatory responses to exercise and Valsalva maneuver are diminished, consistent with centrally mediated, reduced sympathetic, and enhanced parasympathetic activity. Receptor-mediated and probably nonneuronal sites of action account for cannabinoid effects. The endocannabinoid system appears important in the modulation of many vascular functions. Marijuana's cardiovascular effects are not associated with serious health problems for most young, healthy users, although occasional myocardial infarction, stroke, and other adverse cardiovascular events are reported. Marijuana smoking by people with cardiovascular disease poses health risks because of the consequences of the resulting increased cardiac work, increased catecholamine levels, carboxyhemoglobin, and postural hypotension.
Osmotic concentration of fruit slices prior to freeze dehydration.

Organoleptic quality of freeze-dried foods can be improved by increasing the solids content of the food material to levels of 25–35%. This also results in a reduction of the water load to the freeze-drier, which greatly improves the economics of the process. For solid foods, such as fruit slices, the increase in solids concentration is achievable by an osmosis process. Sucrose has generally been the solute of choice, but economic considerations are indicating that the suitability of new osmosis solutes should be evaluated. Several mixed osmosis solutes were evaluated for their effectiveness in concentrating apple slices prior to freeze-drying. Kinetics of water loss and solute uptake were determined for solutions of differing composition and concentration. Several of the osmotically preconcentrated freeze-dried apple slices were evaluated for organoleptic acceptability.