cssi/SciSciGPT-SciSciNet huggingface dataset:
Evaluation of Dynamic [18F]-FDG-PET Imaging for the Detection of Acute Post-Surgical Bone Infection

Diagnosing bone infection in its acute early stage is of utmost clinical importance as the failure to do so results in a therapeutically recalcitrant chronic infection that can only be resolved with extensive surgical intervention, the end result often being a structurally unstable defect requiring reconstructive procedures. [18F]-FDG-PET has been extensively investigated for this purpose, but the results have been mixed in that, while highly sensitive, its specificity with respect to distinguishing between acute infection and sterile inflammatory processes, including normal recuperative post-surgical healing, is limited. This study investigated the possibility that alternative means of acquiring and analyzing FDG-PET data could be used to overcome this lack of specificity without an unacceptable loss of sensitivity. This was done in the context of an experimental rabbit model of post-surgical osteomyelitis with the objective of distinguishing between acute infection and sterile post-surgical inflammation. Imaging was done 7 and 14 days after surgery with continuous data acquisition for a 90-minute period after administration of tracer. Results were evaluated based on both single and dual time point data analysis. The results suggest that the diagnostic utility of FDG-PET is likely limited to well-defined clinical circumstances. We conclude that, in the complicated clinical context of acute post-surgical or post-traumatic infection, the diagnostic utility accuracy of FDG-PET is severely limited based on its focus on the increased glucose utilization that is generally characteristic of inflammatory processes.
Evaluation of elastic compensation using elastic/plastic rotating circular disk problems

Abstract A version of elastic compensation is evaluated in the context of stress and deformation analysis of elastic/plastic rotating circular disks of both constant and variable thicknesses undergoing small deflections. An iterative incremental method is combined with finite difference methodology to generate information about the entire quasistatic loading histories of such disks. The evaluation process involves comparison of representative numerical results with corresponding predictions existing in the literature.
The effects of different methods of preparing cellulose nitrate on the determination of the D/H ratios of non-exchangeable hydrogen of cellulose

Abstract Cellulose nitrate prepared by different methods was subjected to elemental, isotopic, and spectroscopic analysis. Cellulose nitrate prepared by nitration of wood powder was contaminated, most likely by nitrated lignin. Cellulose nitrate prepared by nitration of wood cellulose did not contain this component, and thus provides a more accurate measure of the D/H ratios of non-exchangeable hydrogen of cellulose. However, cellulose nitrate prepared directly from cellulose contained trace amounts of hemicellulose nitrates and was not completely nitrated. These conditions will not cause significant errors in the D/H ratios measured for most samples. Analysis of aliquots of the same samples nitrated by the two methods suggests that published δD values of cellulose nitrate from wood may be in error by 6–8‰ in many cases and occasionally by as much as 15‰.
The role of sugars in western spruce budworm nutritional ecology

. 1 The western spruce budworm, Choristoneura occidentalis Freeman, and Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, have been used to test the hypothesis that variation in levels of foliar sugars form part of the basis for plant resistance to herbivore attack. 2 Budworm population growth was evaluated on artificial diets with 2–45% sucrose using a three generation bioassay. Diets with 1.2% and 3.9% N were tested to determine if responses to sugar were dependent on levels of protein. The 3.9% N diets were supplemented with a mineral salt mixture, so they had high levels of N and minerals. 3 The response of budworm population growth to sucrose concentrations ≤20% was convex at 1.2% N and flat for 3.9% N. Population growth on the 1.2% N diet, which had levels of N and minerals similar to host foliage, was good with only 2% sugar, but optimal at the 6% sucrose level; the number of F1, F2 and F3 larvae produced declined substantially when sugar was increased to 11% and 20%. On the 3.9% N diets, population growth was equivalent for diets with 2% and 11% sucrose. Sucrose concentrations ≥29% were detrimental to the budworm at both N levels. 4 Sugar concentrations in Douglas-fir foliage varied between 5.7% and 18.4%. Thus, results from the 1.2% N experiment indicated that budworm performance was best on diets with sugar concentrations near the lower limit observed for host foliage. This implies that plants with higher foliar sugar may be inferior hosts for the budworm. Field observations supported this conclusion, as putatively resistant Douglas-fir trees had significantly higher levels of sugars in their foliage than nearby paired susceptible trees. Variation in foliar sugars among individual trees may be part of the mechanism in Douglas-fir resistance to C.occidentalis damage.
Fatty acylation of the rat and human asialoglycoprotein receptors. A conserved cytoplasmic cysteine residue is acylated in all receptor subunits.

Functional rat or human asialoglycoprotein receptors (ASGP-Rs) are hetero-oligomeric integral membrane glycoproteins. Rat ASGP-R contains three subunits, designated rat hepatic lectins (RHL) 1, 2, and 3; human ASGP-R contains two subunits, HHL1 and HHL2. Both receptors are covalently modified by fatty acylation (Zeng, F.-Y., Kaphalia, B. S., Ansari, G. A. S., and Weigel, P. H. (1995) J. Biol. Chem.270, 21382-21387; Zeng, F.-Y., Oka, J. A., and Weigel, P. H. (1996) Biochem. Biophys. Res. Commun.218, 325-330). We report here that the single Cys residue in the cytoplasmic domain of each RHL or HHL subunit is fatty acylated. The degree of acylation is ≥90% per subunit. Deacylation of affinity-purified ASGP-Rs with hydroxylamine results in the spontaneous formation of dimers through reversible disulfide bonds, indicating that deacylation concomitantly generates free thiol groups. Reaction of hydroxylamine-treated ASGP-R with [14C]iodoacetamide resulted in the specific incorporation of radioactivity into all RHL and HHL subunits, verifying that fatty acids are attached via thioester linkages. To identify the Cys residue involved in the thioester linkages, 14C-carboxyamidomethylated RHL subunits were separated by SDS-polyacrylamide gel electrophoresis and digested in-gel with trypsin, and the resulting peptides were separated by reverse-phase high performance liquid chromatography. Amino acid sequence of radioactive peptides revealed that Cys35 in RHL1 and Cys54 in RHL2 and RHL3 were radiolabeled and, therefore, are fatty acylation sites. Fatty acylation of HHL subunits was analyzed by site-directed mutagenesis. Metabolic labeling of Cos7 cells transfected with wild type HHL1 cDNA resulted in substantial incorporation of [3H]palmitate into purified HHL1. Incorporation of [3H]palmitate into a C36S mutant of HHL1 was negligible (∼1%) compared with wild type. This result also shows that Cys57 within the transmembrane domain of HHL1 is not normally palmitoylated. We conclude that Cys35 in RHL1, Cys54 in RHL2 and RHL3, and Cys36 in HHL1 are fatty acylated. Cys57 in HHL1 and probably Cys56 in RHL1 are not palmitoylated.
TRICUSPID VALVE TISSUE AS A SITE OF ECTOPIC IMPULSE FORMATION

Many patients following cardiac surgery have supraventricular arrhythmias. Because the tricuspid valve is subjected to surgical manipulation and the canine mitral valve has been shown to be a site of ectopic impulse formation we studied isolated preparations of canine tricuspid valve (TV) and contiguous right atrial (RA) muscle by microelectrode techniques to determine if this tissue has the potential to generate arrhythmias. Unlike the action potentials (AP) recorded from ordinary atrial muscle, AP's recorded from TV-RA demonstrated low maximum diastolic potential, slow upstroke velocity, a prominent plateau phase, and a diastolic afterpotential. All preparations showed spontaneous phase 4 depolarization initially or during superfusion with catecholamines. Impulses originating in the TV conducted to RA. Acetylcholine abolished automaticity and decreased AP amplitude in spontaneously depolarizing TV cells but had minimal effect on ordinary RA cells. This data indicates that ectopic impulses can arise from cells in either TV or contiguous RA. These cells respond to autonomic agents in a similar fashion as other supraventricular pacemaker cells and perhaps may be the site of origin of some of the supraventricular arrhythmias observed postoperatively in the clinical situation.
Analysis of complex mixtures by computer controlled high resolution mass spectrometry: I—application to atmospheric aerosol composition

Techniques are described for the computer reduction and identification of complex high resolution mass spectrometric data to yield qualitative and quantitative data for one hundred or more components in a complex mixture. The procedures described have been applied to direct insertion probe separations coupled with high resolution mass spectrometry. Two mass spectrometer computer systems are described in this paper. The basic techniques were developed at the University of Washington utilizing an A.E.I. MS-9 high resolution mass spectrometer, which was interfaced with a PDP-12 digital computer. The most recent system utilizes a Nova II computer interfaced to a Varian MAT 311 mass spectrometer. Programs were developed which were capable of determining the accurate mass (± 3 millimass) of up to 1000 ions per scan. High accuracy limited mass searches were first used to reduce the data. A correlation program was developed to resolve pure mass spectra from the composite mass spectral data using data obtained from the limited mass searches. A library search program was developed which used up to four major identifying masses and their relative abundances in addition to relative volatilization temperatures (probe) or relative retention times (gas chromatographic) for obtaining qualitative data. Quantitative data for each compound were obtained by comparing the total integrated ion current of one ion fragment to that of an internal standard. Instrumental and computer parameters are discussed with respect to the accuracy of the quantitative work. Final computer results gave compound identification and concentrations in μg/m3 or ppm. The use of this analytical technique for the analysis of complex mixtures of pollutants present in atmospheric aerosols is described.
Epidemiology of cervical spine fractures in the US military

BACKGROUND CONTEXT: The epidemiology of cervical spine fractures and associated spinal cord injury (SCI) has not previously been estimated within the American population. PURPOSE: To determine the incidence of cervical spine fractures and associated SCI and identify potential risk factors for these injuries in a large multicultural military population. STUDY DESIGN: Query of a prospectively collected military database. PATIENT SAMPLE: The 13,813,333 military servicemembers serving in the US Armed Forces between 2000 and 2009. OUTCOME MEASURES: The Defense Medical Epidemiology Database (DMED) was queried to identify all servicemembers diagnosed with cervical spine fractures with and without SCI during the time period under investigation. Data were used to determine the incidence of cervical spine fractures and SCI as well as identify risk factors for their development. METHODS: The DMED was queried for the years 2000 to 2009 using the International Classification of Diseases, Ninth Revision, Clinical Modification code for cervical spine fractures with and without SCI (805.0, 805.1, 806.0, and 806.1). The database was also used to determine the total number of servicemembers within the military during the same period. The incidence of cervical spine fractures and fractures associated with SCI was determined, and unadjusted incidence rates were calculated for the demographic characteristics of sex, race, military rank, branch of service, and age. Adjusted incidence rate ratios were then determined using multivariate Poisson regression analysis to control for other factors in the model and identify significant risk factors for cervical spine fractures and cervical injuries associated with SCI. RESULTS: From 2000 to 2009, there were 4,048 cervical spine fractures in a population at risk of 13,813,333 servicemembers. The overall incidence of cervical spine fractures was 0.29 per 1,000 person-years, and the incidence of fracture associated SCI was 70 per 1,000,000. The cohorts at highest risk of cervical spine fracture were males, whites, Enlisted personnel, those serving in the Army, Navy, or Marine Corps, and servicemembers aged 20 to 29. Risk of fracture-associated SCI was significantly increased in males, Enlisted personnel, servicemembers in the Army, Navy, or Marines, and those aged 20 to 29. CONCLUSIONS: This study is the largest population-based investigation to be conducted within the United States regarding the incidence of SCI and the only study addressing incidence and risk factors for cervical spine fractures. Male sex, white race, Enlisted military rank, service in the Army, Navy, or Marine Corps, and ages 20 to 29 were found to significantly increase the risk for cervical fractures and/or fracture associated SCI. Our findings support previously published data but also represent best available evidence based on the size and diversity of the population under study. LEVEL OF EVIDENCE: Prognostic; Level II. Language: en
T Antigens Encoded by Replication-defective Simian Virus 40 Mutants dl1135 and 5080

We present a preliminary biochemical characterization of two simian virus 40 mutants that affect different T antigen replication functions. SV40 T antigen mutants dl1135 (delta 17-27 amino acids) and 5080 (P-L) have been studied extensively with regard to their ability to transform cells in culture and induce tumors in transgenic mice. Both mutants are defective for viral DNA replication in vivo. In order to assess in more detail the molecular basis for the in vivo replication defects of 5080 and dl1135, we expressed the mutant proteins using the baculovirus system and purified them by immunoaffinity chromatography. With each of the purified proteins, we examined some of the biochemical activities of T antigen required for replication, viz. ATPase, binding to the origin of replication (ori) and assembly on ori, DNA helicase and unwinding, and replication in in vitro assays. Consistent with previous studies, we found that the 5080 protein is defective for multiple biochemical activities including ATPase, helicase, ori-specific unwinding, and ATP-induced hexamerization. However, this mutant retains some sequence-specific DNA binding activity. In contrast, the dl1135 protein exhibited significant levels of activity in all assays, including the ability to drive SV40 DNA replication in vitro. Thus, dl1135 is one of several mutants with an altered amino-terminal domain which can replicate DNA in vitro, but not in vivo. Thus, while the 5080 mutation affects a T antigen enzymatic function directly required for viral DNA synthesis, dl1135 may alter an activity required to prepare the cell for viral replication.
Electricity for groundwater use: constraints and opportunities for adaptive response to climate change

Globally, groundwater use is intensifying to meet demands for irrigation, urban supply, industrialization, and, in some instances, electrical power generation. In response to hydroclimatic variability, surface water is being substituted with groundwater, which must be viewed as a strategic resource for climate adaptation. In this sense, the supply of electricity for pumping is an adaptation policy tool. Additionally, planning for climate-change mitigation must consider CO2 emissions resulting from pumping. This paper examines the influence of electricity supply and pricing on groundwater irrigation and resulting emissions, with specific reference to Mexico—a climate–water–energy ‘perfect storm’. Night-time power supply at tariffs below the already-subsidized rates for agricultural groundwater use has caused Mexican farmers to increase pumping, reversing important water and electricity conservation gains achieved. Indiscriminate groundwater pumping, including for virtual water exports of agricultural produce, threatens the long-term sustainability of aquifers, non-agricultural water uses, and stream–aquifer interactions that sustain riparian ecosystems. Emissions resulting from agricultural groundwater pumping in Mexico are estimated to be 3.6% of total national emissions and are equivalent to emissions from transporting the same agricultural produce to market. The paper concludes with an assessment of energy, water, and climate trends coupled with policy futures to address these challenges.
Photoacoustic monitoring of clot formation during surgery and tumor surgery

When a blood vessel is injured, the normal physiological response of the body is to form a clot (thrombus) to prevent blood loss. Alternatively, even without injury to the blood vessel, the pathological condition called thromboembolism may lead to the formation of circulating blood clots (CBCs), also called emboli, which can clog blood vessels throughout the body. Veins of the extremities (venous thromboembolism), lungs (pulmonary embolism ), brain (embolic stroke), heart (myocardial infarction), kidneys, and gastrointestinal tract are often affected. Emboli are also common complications of infection, inflammation, cancer, surgery, radiation and coronary artery bypass grafts. Despite the clear medical significance of CBCs, however, little progress has been made in the development of methods for real-time detection and identification of CBCs. To overcome these limitations, we developed a new modification of in vivo photoacoustic (PA) flow cytometry (PAFC) for real-time detection of white, red, and mixed clots through a transient decrease, increase or fluctuation of PA signal amplitude, respectively. In this work, using PAFC and mouse models, we present for the first time direct evidence that some medical procedures, such as conventional or cancer surgery may initiate the formation of CBCs. In conclusion, the PA diagnostic platform can be used in real-time to define risk factors for cardiovascular diseases, assist in the prognosis and potential prevention of stroke by using a well-timed therapy or as a clot count as a marker of therapy efficacy.
A new microsporidian parasite of the mosquito Aedes taeniorhynchus.

Abstract A new species of microsporidium is described from the mosquito Aedes taeniorhynchus . This microsporidium is vertically transmitted and exhibits dimorphic development with one sequence leading to formation of short pyriform, uninucleate spores in male fourth instar larvae, pupae, and adults, and the other sequence leading to formation of diplocaryotic stages and cylindrical spores in adult females. Vertical transmission is apparently limited to a single generation, and the uninucleate spores are not transmissible per os to larvae.
Numerical stability of a cyclic adi iteration

We study the influence of round-off errors on a cyclic ADI iteration with variable parameters for solving large sparse and ill-conditioned systems of algebraic equations Au=g. We show that ADI iteration generates the computed solution ũ which approximates the exact solution u with the relative error at most of order kρ, where k is the spectral condition number of a matrix A and ρ is the relative computer precision. The residual norm is bounded by (ln(k) + k 2 ρ)||Apar; ||ũ||ρ. Therefore ADI iteration is stable and the natural residual stopping criterion is reliable.
Electrochemical Quantitation of DNA Immobilized on Gold

We have developed an electrochemical method to quantify the surface density of DNA immobilized on gold. The surface density of DNA, more specifically the number of nucleotide phosphate residues, is calculated from the amount of cationic redox marker measured at the electrode surface. DNA was immobilized on gold by forming mixed monolayers of thiol-derivitized, single-stranded oligonucleotide and 6-mercapto-1-hexanol. The saturated amount of charge-compensating redox marker in the DNA monolayer, determined using chronocoulometry, is directly proportional to the number of phosphate residues and thereby the surface density of DNA. This method permits quantitative determination of both single- and double-stranded DNA at electrodes. Surface densities of single-stranded DNA were precisely varied in the range of (1−10) × 1012 molecules/cm2, as determined by the electrochemical method, using mixed monolayers. We measured the hybridization efficiency of immobilized single-stranded DNA to complementary strands as a...
Development of a Dynamic Decohesion Criterion for Subsonic Fracture of the Interface between Two Dissimilar Materials

We present findings of an experimental study of dynamic decohesion of bimaterial systems composed of constituents with a large material property mismatch. Poly-methylmethacrylate (PMMA)-steel and PMMA-aluminium bimaterial fracture specimens were used. Dynamic one-point bend loading was accomplished with a drop-weight tower device (for low and intermediate loading rates) or a high-speed gas gun (for high loading rates). High-speed interferometric measurements were made using the lateral shearing interferometer of coherent gradient sensing in conjunction with high-speed photography. Very high crack propagation speeds (terminal crack-tip speeds up to 1.5c_s^(PMMA), where c_s^(PMMA) is the shear wave speed of PMMA) and high accelerations (of about 10^7g, where g is the acceleration of gravity) were observed and are reported. Issues regarding data analysis of the high-speed interferograms are discussed. The effects of near-tip three-dimensionality are also analysed. Dynamic complex stress factor histories are obtained by fitting the experimental data to avail-able asymptotic crack-tip fields. A dynamic crack growth criterion for crack growth along bimaterial interfaces is proposed. In the subsonic regime of crack growth it is seen that the opening and shearing displacements behind the propagating crack tip remain constant and equal to their value at initiation, i.e. the crack retains a self-similar profile during crack growth at any speed. This forms the basis of the proposed dynamic interfacial fracture criterion.
Up-regulation of inducible nitric oxide synthase in the substantia nigra by lipopolysaccharide causes microglial activation and neurodegeneration

The present study was designed to examine whether expression of iNOS was involved in LPS-induced neurodegeneration in rat substantia nigra (SN) and to study the role of NO in the loss of the SN dopaminergic neurons. In Western blot analysis, iNOS was induced in the SN after injection of LPS in a time- and dose-dependent manner. Immunofluorescence and immunohistochemical analyses revealed that the iNOS is located in a fully activated microglia with the characteristic amoeboid morphology. Furthermore, LPS-induced loss of dopaminergic neurons was significantly inhibited by the administration of L-N(G)-nitroarginine, a selective inhibitor of NOS, and the glucocorticoid dexamethasone. These inhibiting agents for iNOS reduced LPS-induced microglial activation, suggesting that NO has a role in inflammatory-mediated microglial activation. These results demonstrate that LPS induces the expression of iNOS in activated microglia in the SN, and that NO and/or its metabolites may play a crucial role in inflammation-mediated degeneration of dopaminergic neurons.
Cycles in metagraphs

Modeling information systems using metagraphs provides a versatile basis for the visualization and analysis of such systems. In a metagraph, directed edges are defined between sets of elements, rather than between individual elements, as is the case with directed graphs. This facilitates representation of the rich interactions that are found among the components of an information system, such as files, models, and rules. We show that mutual dependencies in a system can be represented by cycles in metagraphs. Specifically, we examine the properties of metagraph cycles, demonstrate that metagraphs provide a more powerful tool for modeling cyclic behavior than do traditional graphical tools, and investigate their usefulness in the design and integration of information systems. >
Design layout of hydrogen research and development garage

Abstract Research and development programs toward fuel cells and other hydrogen technologies have increased significantly during the past two decades. These programs require appropriate facilities to undertake the research and development programs. This paper discusses the design layout of one such facility, the “Missouri S&T EcoCAR Hydrogen Vehicle Garage”, which can be used as a model while designing a hydrogen R&D garage. The Missouri S&T EcoCAR garage is a 12.2 m × 7.6 m garage situated at the Missouri University of Science and Technology (Missouri S&T) and serves as the headquarters for the Missouri S&T EcoCAR team. Within the garage, students will gain real-world, hands-on experience by transforming a standard production vehicle into a hydrogen Fuel Cell Plug-in Hybrid Electric Vehicle (FC-PHEV). The garage is classified as a Class 1 Division 2, Group B hazardous location and is equipped to safely test and integrate the vehicle prototype. Specifically, the design includes (i) a hydrogen gas detection system, (ii) hazardous location electrical service, heating, ventilation and air-conditioning, lighting, and compressed air systems, and (iii) emergency backup electric power system with alarms/monitors/security cameras for the hydrogen R&D facility. The garage will be connected to an external backup power supply unit which will be powered by a PEM fuel cell.
A gas chromatographic method for the microdetermination of iodine

Iodine was quantitatively converted by reaction with acetone to a form which was easily separated by gas chromatography and which was easily detected with an electron capture detector. Linear response of the detector was obtained for solutions which contained up to 1μg/ml with an uncertainty of 8%. Milligram amounts of chloride or bromide andμg amounts of iodide do not interfere. Amplification of the amount of reaction product and the determination of both iodine and iodide was accomplished by the addition of KIO3.
3-D simulation of arbitrary crack growth using an energy-based formulation – Part II: Non-planar growth

Abstract The energy-based growth formulation and accompanying simulation technique introduced in Part I of this series is generalized in this work to predict arbitrary, mixed-mode, non-planar crack evolution. The implementation uses a novel basis-function approach to generate a crack extension expression, rather than relying on the local, point-by-point approach described in Part I. The basis-function expression dampens the effect of numerical noise on crack growth predictions that could produce numerically unstable simulation results. Two simulations are presented to demonstrate the technique’s ability to capture both general non-planar behavior, as well as local mixed-mode phenomena, e.g. “factory-roof” formation, along the crack front.
An Investigation of Polymer Diffusion in Hydrogel Laminates Using Near-Field FTIR Microscopy

The role of diffusion in gel/gel adhesion was examined by near-field FTIR microscopy. Using a near-field FTIR microscopy technique, compositional maps were obtained with improved spatial resolution and enhanced signal to noise ratio. With this technique, the resolution was enhanced by about a factor of 5. Polymer chain diffusion across a gel/gel interface was a substantial mechanism of adhesion. Diffusion of poly(ethylene glycol) (PEG) free chains across poly(acrylic acid) (PAA) gels was investigated. The diffusivity of PEG was on the order of 10-8 to 10-9 cm2/s for these swollen polymer gels. PEG diffusivity in PAA gels scaled to M-0.41. This was similar to values reported for PEG diffusion in aqueous solution.
Follow-up of carriers of BRCA1 and BRCA2 variants of unknown significance: Variant reclassification and surgical decisions

Purpose: Approximately 5–10% of patients who undergo genetic testing of BRCA1 and BRCA2 receive a variant of unknown significance (VUS) result. The ambiguous nature of a VUS may increase difficulty in patient understanding and decision making regarding risk reduction and surveillance options, including cancer risk-reducing surgeries. VUS reclassification to benign or deleterious may occur in time; however, clinical decisions may need to be made expeditiously, and some patients may pursue irreversible treatments before VUS reclassification. Methods: We reviewed the surgical decisions of 107 women postdisclosure of a BRCA VUS result counseled at our institute between 1998 and 2009. Conclusion: Among women receiving a BRCA VUS result at our center, 11 of 107 (10.3%) pursued cancer risk-reducing mastectomy and 22 of 107 (20.6%) pursued cancer risk-reducing bilateral salpingo-oophorectomy. Reclassification of VUS occurred up to 9 years after testing, and 5 of 22 (22.7%) women followed up for 8 or more years continue to have a VUS result. We discuss considerations for providers of genetic services to discuss with patients who receive a VUS result.
A Comparison Between Axisymmetric and Slab-Symmetric Cumulus Cloud Models

Abstract Axisymmetric and slab-symmetric cumulus cloud models with Kessler's parameterizations for microphysical processes are developed. By using a staggered grid arrangement and applying a modified upstream difference scheme, erroneous behavior in the center of a simulated cloud, which would result with the use of the ordinary upstream difference scheme, is eliminated. A comparison between the present two models of different geometries confirms in general the conclusions reached in previous studies: the updraft in an aixsymmetric model grows more vigorously than in a slab-symmetric model. However, the ratio of the maximum updraft in the slab-symmetric model to that in the axisymmetric model is 0.53 in this study, notably larger than Murray's 0.12. An analysis of the pressure gradient force associated with could motions reveals that the vertical pressure gradient force due to perturbed pressure is: 1) of the same order of magnitudes as that of the thermal buoyancy force in the core region of the cloud; i...
Resistance of Rosa microtubule polymerization to colchicine results from a low-affinity interaction of colchicine and tubulin

The inhibition of the polymerization of tubulin from cultured cells of rose (Rosa. sp. cv. Paul's scarlet) by colchicine and the binding of colchicine to tubulin were examined in vitro and compared with data obtained in parallel experiments with bovine brain tubulin. Turbidimetric measurements of taxol-induced polymerization of rose microtubules were found to be sensitive and semiquantitative at low tubulin concentrations, and to conform to some of the characteristics of a nucleation and condensation-polymerization mechanism for assembly of filamentous helical polymers. Colchicine inhibited the rapid phase of polymerization at 24°C with an apparent inhibition constant (Ki) of 1.4·10-4 M for rose tubulin and an apparent Ki=8.8·10-7 M for brain tubulin. The binding of [3H]colchicine to rose tubulin to form tubulin-colchicine complex was mildly temperature-dependent and slow, taking 2–3 h to reach equilibrium at 24°C, and was not affected by vinblastine sulfate. The binding of [3H]colchicine to rose tubulin was saturable and Scatchard analysis indicated a single class of low-affinity binding sites having an apparent affinity constant (K) of 9.7·102 M-1 and an estimated molar binding stoichiometry (r) of 0.47 at 24°C. The values for brain tubulin were K=2.46·106 M-1 and r=0.45 at 37°C. The binding of [3H]colchicine to rose tubulin was inhibited by excess unlabeled colchicine, but not by podophyllotoxin or tropolone. The data demonstrate divergence of the colchicine-binding sites on plant and animal tubulins and indicate that the relative resistance of plant microtubule polymerization to colchicine results from a low-affinity interaction of colchicine and tubulin.
Photochemical transformations XXV: quenching experiments in the triplet-sensitized conversion of norbornadiene to quadricyclene

Abstract The photochemical isomerization of norbornadiene to quadricyclene, sensitized by acetone, acetophenone and benzophenone, is investigated. Quenching of these reactions with piperylene and with 2,5-dimethyl-2,4-hexadiene indicates that triplet excitation transfer from these ketones to norbornadiene occurs with rate constants of about 10 9 l mol −1 s −1 . The initial products of excitation transfer to norbornadiene either have lifetimes of less than 1 ns or are converted almost completely to quadricyclene, regardless of whether they undergo “natural” decay or whether they decay by interaction with quencher.
The utility of the A1 and A2 criteria in the diagnosis of PTSD.

Abstract In the field of posttraumatic stress disorder (PTSD), the revisions to the DSM-IV definition of a potentially traumatic event are contentious. Proponents praise the subjective emphasis, while others contend that the changes to the criterion broadened the conceptualization of PTSD. This study examined the predictive utility of Criterion A events, examining the stressor (A1) and subjective emotional response (A2) components of the definition of a traumatic event. Rates of Criterion A events and PTSD were calculated for three diverse samples, and predictive power, sensitivity, specificity, and ROC curves were computed to determine the predictive utility of Criterion A requirements for PTSD symptom, duration, and functional impairment diagnostic criteria. Across all samples, the current Criterion A requirements did not predict much better than chance. Specifically, A2 reports added little to the predictive ability of an A1 stressor, though the absence of A2 predicted the absence of PTSD-related symptoms, their duration, and impairment. Notably, the combination of three A1 and A2 criteria showed the best prediction. Confronted events also showed less predictive ability than experienced events, with more variable performance across samples. These results raise fundamental questions about the threshold or “gate” that Criterion A ought to play in our current nosology.
Intermolecular Overhauser effects in fluoroalcohol solutions of cyclo-alanylglycine.

Interactions between the diketopiperazine cyclo-alanylglycine and four fluorinated alcohols in water–fluoroalcohol mixtures were examined by 1H{19F} intermolecular nuclear Overhauser effects (NOE) experiments. The alcohols studied were trifluoroethanol, hexafluoroacetone trihydrate, 1,1,1,3,3,3-hexafluoroisopropanol and perfluoro-t-butanol. The experimental methods used permit detection of solvent–solute NOEs of 0.1% or less. Solute and solvent diffusion coefficients were determined and apparent molecular radii of the fluoroalcohols estimated. Using these data, it was shown that observed 1H{19F} intermolecular NOEs are consistent with expectations based on theory. A method for extending conventional theory to take into account the shape of a solute and the exposure of its hydrogens to solvent is described. This approach gives reasonable agreement with experimental results, particularly if it is assumed that solute–solvent interactions take place in such a way that the fluorines of a fluoroalcohol are preferentially oriented toward the solute during solute–solvent encounters. The results support the suggestion that intermolecular 1H{19F} NOEs may become a useful tool for studies of peptide and protein conformations in fluoroalcohol–water solvent mixtures. © 2002 Wiley Periodicals, Inc. Biopolymers 64: 227–235, 2002
Correlation of the interpretation of fetal heart rate records with cord plasma erythropoietin levels

Summary. On the basis that fetal levels of plasma erythropoietin (Ep) may reflect fetal oxygenation the primary purpose of the present study was to assess the relation between Ep measured in cord plasma at delivery and the intrapartum fetal heart rate (FHR) record. A scoring system for interpreting FHR recordings blindly was prospectively utilized in 41 selected human pregnancies during the 4 h immediately preceding birth. The correlation of the overall mean FHR score for each individual patient with cord plasma Ep was significant such that the highest Ep levels were observed in those infants with the most abnormal FHR scores. Furthermore, when the birthweights of the infants were adjusted for gestational age, sex, and birth order, birthweight centile was negatively correlated with cord plasma Ep. When both FHR score and birthweight were simultaneously correlated with cord plasma Ep using multiple regression, the combined effect of these two factors improved the association of either alone with both contributing approximately equally.
Optimal Exponential Difference Scheme for Solving Parabolic Partial Differential Equations

The existing single-step finite-difference schemes for solving time-dependent parabolic partial differential equations become, due to the inadequate approximation of the time derivative, either inaccurate or unstable, or introduce spurious oscillations in the solution when the time step is relatively large. An optimal single-step exponential scheme is developed herein based on a study of the analytic behavior of time variation of the time derivative. Its excellent performance is demonstrated by its application to the one-dimensional transient diffusion equation. The comparison among a class of commonly used existing single-step schemes shows that it is by far the most accurate for a wide range of time steps. Its performance, the author believes, could be even more optimized if it is utilized in the context of an algorithm that automatically varies the time step based on the local truncation error. Generalizations to multidimensional problems are also discussed.
A Pilot Study of Normobaric Oxygen Therapy in Acute Ischemic Stroke

Background and Purpose— Therapies that transiently prevent ischemic neuronal death can potentially extend therapeutic time windows for stroke thrombolysis. We conducted a pilot study to investigate the effects of high-flow oxygen in acute ischemic stroke. Methods— We randomized patients with acute stroke (<12 hours) and perfusion-diffusion “mismatch” on magnetic resonance imaging (MRI) to high-flow oxygen therapy via facemask for 8 hours (n=9) or room air (controls, n=7). Stroke scale scores and MRI scans were obtained at baseline, 4 hours, 24 hours, 1 week, and 3 months. Clinical deficits and MR abnormalities were compared between groups. Results— Stroke scale scores were similar at baseline, tended to improve at 4 hours (during therapy) and 1 week, and significantly improved at 24 hours in hyperoxia-treated patients. There was no significant difference at 3 months. Mean (±SD) relative diffusion MRI lesion volumes were significantly reduced in hyperoxia-treated patients at 4 hours (87.8±22% versus 149.1±...
In vitro steroid secretion by staged spermatocysts (sertoli/germ cell units) of dogfish (Squalus acanthias) testis☆

Using the dogfish shark (Squalus acanthias) testis model in which different germ cell stages are topographically separated, we previously observed that steroidogenic enzyme activities vary qualitatively and quantitatively during spermatogenesis. To determine whether these data, obtained by radiolabeled tracer analysis of testicular microsomes, accurately predict steroid secretion by intact cultured spermatocysts (germ cell/Sertoli cell units), steroids were radioimmunoassayed directly in spent medium. Steroid output in basal medium was low, but after addition of 25-hydroxycholesterol (25-OH chol, 60 microM), large amounts of progestins (P) and testosterone (T) accumulated. Dehydroepiandrosterone (DHEA), androstenedione (A), and estradiol (E2) were low or nondetectable in the presence or absence of 25-OH chol; however, addition of T (1 microM) as substrate elevated E2 above assay limits. T and P contents of media increased progressively over a 24-hr culture period (Day 1). Replacement and analysis of spent media at 24-hr intervals indicated that secretion was continuous up to 6 days after seeding, although secretory rates (T plus P) and T/P ratios changed with time in culture. Spermatocysts in premeiotic (PrM), meiotic (M), and post-meiotic (PoM) stages all secreted T and P; however, absolute values, T/P ratios, and stage-dependent patterns varied from one experiment to another with no obvious seasonal pattern. Also steroid secretion by staged cysts did not consistently agree with predictions based on steroidogenic enzyme activities measured in earlier cell-free assays, whether or not 25-OH chol was present. This discrepancy was not explained by stage-related patterns of steroid secretion vs retention or by addition of putative in vivo regulators. Agents that elevated P and/or T were dibutyryl cyclic AMP, 1-isobutyl-3-methylxanthine (IBMX), and forskolin, whereas ventral lobe extract and Ca2+ ionophore (A23817) were inhibitory. An autoregulatory feedback loop was indicated by a negative relationship between cyst concentration per well and steroid secretion rate. In contrast to T and P, E2 secretion in the presence of substrate (T, 1 microM) was as predicted from previously determined patterns of aromatase activity (M > PrM > PoM) and increased in response to IBMX. Added [3H]P, [3H]T and [3H]E2 all were extensively metabolized to polar products and P metabolism was stage related (PoM > M > PrM). These data indicate that analysis of free P, T, and E2 in static cyst cultures may underestimate true steroidogenic potential. Assuming further characterization of the system, we conclude that cultured spermatocysts from dogfish testis have potential for studying the multifactorial regulation of steroid synthesis and secretion stage-by-stage during spermatogenesis.
Polarization Correlation in a Quasi-1-D Random System

Statistical correlation of polarization of microwave radiation from randomly positioned spheres inside a circular waveguide is investigated. Cross correlation vanishes in cylindrical coordinates but not in other orthogonal coordinate systems except on the waveguide axis.
Within-group variation in coat-color characteristics of the common tree shrew,Tupaia glis diard, 1820

Pelts of the common three shrew Tupaia glis from Southeast Asia have been examined to determine the degree of seasonal variation and sexual dimorphism. Sexual dimorphism in the pelts occurred on the venter and was variable in expression. Two molting periods could be determined, one in the first half of the year and one in the latter half. The difference between the two pelts was varied, and the variation generally appeared to be correlated with the geographical distribution of the sample. Specimens from coastal sites appeared to exhibit minimal differences between the two seasonal coats, whereas specimens from inland sites molted to a dark pelt in May and June and to a lighter pelt in September through December.
Assessing patterns of oak regeneration and C storage in relation to restoration-focused management, historical land use, and potential trade-offs

Abstract Restoration of composition, structure, and function in oak dominated ecosystems is the focus of management in temperate forests around the world. Land managers focused on oak ecosystem restoration are challenged by the legacy effects of complex land-use histories, urbanization, climate change, and potential stakeholder response to management. Trade-offs may exist between managing forests for climate mitigation (e.g., maximizing C storage or sequestration) and promoting shade-intolerant species historically associated with frequent or high-severity disturbances. This study assessed the potentially conflicting goals of sustained live biomass accrual and increased oak regeneration in the East Woods Natural Area at The Morton Arboretum in Lisle, IL, USA. We evaluated how biomass trends and oak regeneration were related to management regimes, land-use history, current stand structure and composition, and topoedaphic factors. Our results indicated no significant trade-off between sustained live biomass accrual and oak regeneration. Live biomass was increasing across the landscape (biomass increment averaged 18,186 kg ha−1 yr−1) and was not strongly related to differences in management or land-use history. Oak regeneration was rare, especially beyond the seedling stage (∼226 seedlings and 9 saplings ha−1) and was also not strongly related to recent management. Our results indicate that even 20+ years of annual prescribed burning combined with understory thinning has failed to produce the open canopy conditions and high light availability that are necessary for successful oak recruitment. The absence of any trade-offs between biomass accrual and oak regeneration may, therefore, be largely related to the ineffectiveness of current management for promoting oak regeneration. More intensive management utilizing canopy manipulations could produce greater trade-offs, but is likely necessary to establish and release oak regeneration.
THE STATUS OF NEUTRAL CURRENTS

As made apparent by many of the previous lectures, the situation of particle physics today is quite puzzling. On the one hand, the Standard Model (SM) of strong and electroweak interactions is consistent with all confirmed experimental data but theoretically rather unsatisfactory. On the other hand, none of the many theoretical speculations which try to go beyond the SM has (yet) received the slightest experimental support. The solution to this dilemma can only come from new data: either from the detection of a new particle threshold at high energy colliders, or from the appearance of some small discrepancy in high-precision experiments. A crucial sector for testing the SM and its extensions is that of neutral currents (NC), where an impressive amount of data has been collected in recent years. While waiting for the next generation of experiments, it is certainly useful to take stock of our knowledge, determining the NC parameters as precisely as we can and putting limits on possible deviations from the SM. The present talk contains the results of a recent analysis along these lines [1]: the first part illustrates how a set of ‘model-independent’ parameters can be extracted from the available NC data, the second part particularizes the analysis to the SM and to some superstring-inspired models with an additional Z ′ in their low-energy spectrum.
Emerging China and Critical Geopolitics: Between World Politics and Chinese Particularity

A prominent political and human geographer assesses the rise of contemporary China through the lens of critical geopolitics. In doing so he challenges both (a) conventional world political views of China as merely the most recent world power to emerge through a natural process of linear succession ("the linear narrative") and (b) conceptions of the country as a completely unique phenomenon shaped by a distinct historical experience and cultural particularity ("Sino-centrism"). The paper develops the argument that China's rise rather is shaped by a contradictory amalgam of Western-style nationalism and a traditional totalistic conception of world order that is reactive to and dependent on current world politics.