cssi/SciSciGPT-SciSciNet huggingface dataset:
Repair of DNA damage induced by methylating agents in human uterine cervical cells with or without cancer precursor lesions

Abstract Experiments were carried out to study the repair capabilities of normal human cervical fibroblasts and fibroblasts derived from human uterine cervical dysplasia, carcinoma in situ and invasive carcinoma. Sedimentation analysis of DNA in alkaline sucrose density gradient was carried out to monitor the DNA damage induced by a methylating carcinogen, methylnitrosourea (MNU). The results indicate that none of the cell lines, namely, fibroblasts either derived from normal human uterine cervix (T 30 -11) or from cervical cells of cancer precursor lesions (T 4 -3F; T 23 -3; T 18 ) exhibited any significant repair in 72 h. In contrast fibroblasts derived from normal human skin (GM105) exhibited 38% repair of their DNA damaged by MNU. Epithelial-like cells (T 4 -3E) obtained from cervical dysplasia exhibited only 18% repair of MNU-induced DNA damage in 72 h. When the damage was induced by another methylating agent, methyl methanesulfonate (MMS), fibroblasts from normal human skin (GM105) exhibited 40% repair of the damaged DNA whereas fibroblasts from normal human uterine cervix (T 30 -11) exhibited only a 16% repair, in 72 h. These results suggest that fibroblasts derived from either normal human uterine cervix or from cervix with cancer precursor or cancer lesions exhibit low levels of repair of DNA damged by methylating agents.
Asymmetrical self-assembly from fluorinated and sulfonated block copolymers in aqueous media

Block copolymers of fluorinated isoprene and partially sulfonated styrene form novel tapered rods and ribbon-like micelles in aqueous media due to a distribution of sulfonation sites and a large Flory–Huggins interaction parameter. A combination of microscopy, light scattering, and simulation demonstrates the presence of these unique nanostructures. This study sheds light on the micellization behavior of amphiphilic block polymers by revealing a new mechanism of self-assembly.
Switch of flow direction in an Antarctic ice stream

Fast-flowing ice streams transport ice from the interior of West Antarctica to the ocean, and fluctuations in their activity control the mass balance of the ice sheet. The mass balance of the Ross Sea sector of the West Antarctic ice sheet is now positive—that is, it is growing—mainly because one of the ice streams (ice stream C) slowed down about 150 years ago1. Here we present evidence from both surface measurements and remote sensing that demonstrates the highly dynamic nature of the Ross drainage system. We show that the flow in an area that once discharged into ice stream C has changed direction, now draining into the Whillans ice stream (formerly ice stream B). This switch in flow direction is a result of continuing thinning of the Whillans ice stream and recent thickening of ice stream C. Further abrupt reorganization of the activity and configuration of the ice streams over short timescales is to be expected in the future as the surface topography of the ice sheet responds to the combined effects of internal dynamics and long-term climate change. We suggest that caution is needed when using observations of short-term mass changes to draw conclusions about the large-scale mass balance of the ice sheet.
MO‐F‐BRC‐03: Respiratory Motion Assessment of Liver Tumor during Free‐Breathing CBCT Scans Using Continuous B‐Spline Deformation

Purpose: To assess three‐dimensional livertumor movements during free‐ breathing CBCT scans. Methods: In this study, two CBCT scans were acquired for the same treatment position: one with breath hold (BH) and the other with free breathing (FB). First, BH‐CBCT images were reconstructed. Then the BH‐CBCT images were deformed into FB‐CBCT images through a bspline deformation map estimated based on scatter‐corrected FB‐CBCT projections. The FBCBCT projections were taken as a continuous data stream. As the gantry rotated, the deformation map was updated continuously. A liver case was studied using two methods. One method is to only use projections from current breath cycle and the other one is to combine projections of same respiratory phases from three breath cycles. Both methods were implemented based on an open source software (plastimatch) and accelerated by GPU. We evaluated the performance of the proposed methods by comparing tumor centroid trajectories in 4D CT and 4D CBCTimages. Results: Both methods were able to detect tumor movements along all three dimensions. In the tested case, the tumor moved 11.0, 3.7, and 4.3 mm along the longitudinal, lateral, and vertical directions, respectively. The maximum detection errors were 0.8, 1.4, and 3.2 mm for the single‐breath‐cycle method. The maximum detection errors were 1.5, 1.0, and 1.2 mm when projections from three breath cycles were combined. Conclusions: The study showed that it is feasible to detect three‐ dimensional respiratory motion of livertumor using continuous B‐spline deformation.
The effect of fiber orientation on fatigue crack propagation in SCS-6/Ti-15-3 composites

Abstract The fatigue crack propagation behavior of [0/90] s and [0/±45] s SCS-6/Ti-15-3 laminates at room temperature was studied and compared with that of a [0] 6 laminate. The testing was conducted in a tension-tension mode on specimens with a chevron notch perpendicular to the 0° surface layer. The maximum applied stress intensity ranged from 20 to 30 MPam 1/2 . The fatigue crack growth rates at various applied stress intensity levels were measured and the fatigue damage mechanisms were examined. It was found that fatigue crack damage in angle-ply SCS-6/Ti-15-3 laminates is much more complex than that identified in their unidirectional counterparts. The primary crack which originated from the notch interacted with secondary cracks, resulting in catastrophic failure of the laminate. Also, the direction of fatigue crack growth and the final crack length differed in each layer of the angle-ply laminates.
The centre and the frontier: Ottoman cooperation with the North African corsairs in the sixteenth century

Sixteenth-century North Africa, the "Forgotten Frontier" between two rival empires, the Habsburgs and the Ottomans, came into the latter's orbit with the incorporation of the North African corsairs into the Ottoman empire. The employment of these corsairs and the incorporation of their lands created opportunities as well as problems. This article aims to highlight the reasons behind and the limits of the cooperation between North African corsairs and Istanbul when the importance of the former for the latter reached its zenith, in tandem with the Ottoman-Habsburg rivalry in the Mediterranean. It furthermore tries to demonstrate the details of the relationship between the imperial centre in Istanbul and the frontier provinces of North Africa with its centrifugal elites. Thus it reveals the diversity of Ottoman administrative practices as well as the pragmatism and flexibility of the Ottoman government. Finally, it delineates the role that the corsairs played in the shaping of the Mediterranean strategy of the Ottoman empire.
Extracorporeal Removal Techniques for the Poisoned Patient: A Review for the Intensivist

The kidney is able to rapidly eliminate many water-soluble xenobiotics (exogenous chemicals). However, in the face of extraordinary serum concentrations of these xenobiotics or renal dysfunction, alternative elimination techniques often become necessary. Extracorporeal removal (ECR) techniques are used to increase the clearance of xenobiotics. These techniques include hemodialysis (HD), charcoal hemoperfusion (HP), and modalities grouped under the heading of continuous renal replacement therapy (CRRT): continuous venovenous hemofiltration (CVVH) and continuous venovenous hemodiafiltration (CVVHDF). Extracorporeal removal is limited to patients with significant or potentially significant clinical poisoning because the resources required to perform ECR are great. Therefore, most patients who are treated with these techniques are being cared for in intensive care units (ICUs). Our goal in this review is to discuss the properties that make xenobiotics amenable to removal by ECR and the advantages and disadvantages of the individual techniques. We discuss xenobiotics that constitute clear indications for ECR, including the toxic alcohols, salicylates, and lithium. We review the use of CRRT, a modality for which clear indications for treatment of poisonings are currently lacking.
Evolutionary biology: re-crowning mammals.

The evolutionary history of mammals is being tackled both through molecular analyses and through morphological studies of fossils. The 'molecules versus morphology' debate remains both vexing and vibrant.
Differential techniques for the kinetic analysis of DSC data

Abstract A simple technique for the kinetic analysis of rate vs. time data from an isothermal DSC experiment is presented. Selected ascending or descending sections of the rate curve are fitted to dq/dt = k[qo ± q)n Values for n are determined and their consistency tested by the ratios of times to reach reduced rates of reaction.
Intraventricular conduction intervals during orthograde conduction in patients with complete heart block.

His to ventricular activation (H-V) time intervals were evaluated during periods of orthograde conduction in five patients with electrocardiographic evidence of intraventricular conduction abnormalities who developed complete heart block (CHB). During CHB the site of block appeared to be in the intraventricular conduction system rather than in the A-V node. Normal H-V time intervals were found in four of the five patients during orthograde conduction. Three of these patients developed CHB within two-four days of their His bundle studies. These findings demonstrate that the presence of a normal intraventricular conduction time, as determined from the His bundle electrogram, does not preclude development of CHB within a relatively brief interval in patients with intraventricular conduction defects.
Variation of Opioid Use in Pediatric Inpatients Across Hospitals in the U.S.

Abstract Context Appropriate use of opioids is essential to manage moderate-to-severe pain in children safely and effectively, yet published guidance regarding opioid treatment for pediatric patients is limited, potentially resulting in excessive variation in opioid use in pediatric patients across hospitals in the U.S. Objectives The aim was to evaluate hospital variation in opioid use in pediatric inpatients. Methods Using data from the Pediatric Health Information System and the Premier Perspective Database regarding all pediatric inpatients in 626 hospitals, we examined hospital variation in opioid use and the length of opioid use, adjusting for patient demographic and clinical characteristics and for hospital type (children's vs. general) and hospital patient volume, using multilevel generalized linear regression modeling. Results Overall, 41.2% of all pediatric hospitalizations were exposed to opioids. Among the exposed patients, the mean length of exposure was 4.6 days. Exposure proportion and exposure length varied substantially across hospitals, even after accounting for patient demographic and clinical characteristics, hospital type and hospital patient volume, especially among terminal hospitalizations. For patients discharged alive vs. died, the adjusted exposure percentage for each hospital ranged from 0.7% to 99.1% (interquartile range [IQR]: 35.3%–59.9%) vs. 0.1% to 100.0% (IQR: 29.2%–66.2%), respectively, and the adjusted exposure length ranged from 1.0 to 8.4 days (IQR: 2.2–2.7 days) vs. 0.9 to 35.2 days (IQR: 4.0–7.4 days). Conclusion The substantial hospital-level variation in opioid use in pediatric inpatients suggests room for improvement in clinical practice.
A Review of Thermally Controlled Covalent Bond Formation in Polymer Chemistry

Abstract The purpose of this paper is to review known art in the area of thermally controlled covalent linkage formation for use in thermally reversible polymer systems. Only 1 :1 adduct forming reactions are considered in this paper; e.g., condensation reactions are not discussed because these reactions are controlled via the addition or elimination of small molecules. In the case of an exothermic process, covalent bonds would form at lower temperatures and disassemble at higher temperatures. Linkage formation could ideally be extended to either linear polymerizations or crosslinking schemes, as outlined in Fig. 1.
Transmetallation of a binuclear complex of nickel(O). Synthesis and structure of [NiAu(CNMe)2(dppm)2]Cl

Abstract The metallation of Ni2(μ-CNMe)(CNMe)2(dppm)2 (1) (dppm = PPh2Ch2PPh2) with (PPh3)Au(Cl) affords the transmetallation product, [NiAu(CNMe)2(dppm)2]Cl (2) in 49% yield. The 31P NMR spectrum of 1 is an AA′BB′ spin system centered at δ- 39.2 ppm. An X-ray structural study of the title compound was undertaken. Complex 2 crystallizes in the monoclinic space group Pn with a 12.992(1) A, b 11.760(1) A, c 17.579(5) A, β 109.36(2)°, V 2534(1) A3, and Z = 2. The structure was refined to convergence leading to R and R w of 0.020 and 0.025, respectively, for 3062 observations in the range 4° 3.0 σ(I) and Mo-Kα radiation. The NiAu separation is 3.0146(9) A suggesting there is not a significant NiAu interaction. The complex exhibits a cis-trans arrangement of the bridging dppm diphosphine ligands with essentially tetrahedral NiP2L2 (L = CNMe) and linear AuP2 centers.
Critical care nephrology: Core Curriculum 2009.

In the inpatient setting, a high proportion of nephrology consultations are requested for patients in the Intensive Care Unit (ICU). These patients may have acute kidney injury (AKI) or may be critically ill and have end-stage renal disease (ESRD). Thus, nephrologists need to understand recent evidence-based advances in the field of critical care, as well as areas of ongoing controversy and investigation. In this article, we summarize the diagnosis and management of shock, as well as the management of sepsis, acute lung injury/acute respiratory distress syndrome (ALI/ARDS), and fulminant hepatic failure, all of which are associated with high mortality in the critical care setting. We discuss infectious complications of critical care, including ventilator associated pneumonia and catheter related infections. Supportive care, including nutrition, insulin therapy and anemia management are reviewed. Dialysis considerations in critically ill patients are discussed. Lastly, we review the management of several life-threatening intoxications, many of which require early recognition and consideration of dialysis.
A simple proof of a time-space trade-off for sorting with linear comparisons

Abstract It is shown how to extend the techniques originally used to prove a lower bound of Ω( n 2 ) for the product of the time and space consumed for sorting in branching programs with elementary comparisons, to the case of linear branching programs where linear functions on n input elements can be computed in unit time.
Environmental exposures to polychlorinated biphenyls (PCBs) among older residents of upper Hudson River communities.

Abstract The upper Hudson River has been heavily contaminated with polychlorinated biphenyls (PCBs) due to discharges from former electrical capacitor plants in Hudson Falls and Fort Edward, NY. An epidemiologic study was conducted to assess the impact of dietary and residential exposure on PCB body burden among older, long-term, non-occupationally exposed adults living in the vicinity of these former capacitor plants. The study population consisted of 133 persons 55–74 years of age who had lived in Hudson Falls or Fort Edward for 25 years or more. The comparison group consisted of 120 persons from Glens Falls, which is upriver. Both groups were interviewed, and blood samples were obtained for congener-specific PCB analysis. Persons from the study area reported greater past consumption of Hudson River fish than did the comparison area, but current rates were very low in both areas. The geometric mean serum PCB concentrations for the study and comparison populations did not differ significantly (3.07 ppb wet weight and 3.23 ppb, respectively, for total PCB). Serum PCB concentrations increased with cumulative lifetime exposure to PCBs from Hudson River fish consumption ( p
An in Vitro Model of Cyclosporine-Induced Nephrotoxicity

The predominant hypothesis for cyclosporine-induced acute renal failure is postulated to be prerenal vasoconstriction with concomitant hemodynamic changes; an alternate hypothesis, however, may be that cyclosporine (CsA) affects intrarenal processes, i.e., direct renal parenchymal cell injury. However, reports on this direct effect of CsA on renal parenchymal cells are contradictory. Therefore, the purpose of this study was to address whether CsA is directly toxic to renal parenchymal cells in a primary culture system of rat renal cortical epithelial cells. The cytotoxicity of Sandimmune, the commercial form of CsA in a polyoxyethylated castor oil vehicle (Cremophor), CsA without vehicle, and the Cremophor vehicle was assessed by plasma membrane integrity (lactate dehydrogenase leakage), mitochondrial metabolic activity [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction], and gross morphology (phase-contrast microscopy). The cytotoxicity of Sandimmune was also assessed by lysosomal activity (neutral red uptake), by proximal tubular enzyme activity (alkaline phosphatase), and by three fluorescent probes using a multiwell scanner. The three fluorescent probes were propidium iodide which stains nuclei of nonviable cells; bis-carboxyethyl-carboxyfluorescein which is retained by viable cells; and rhodamine 123, which assesses mitochondrial membrane potential. The results of this study demonstrated that Sandimmune caused dose- (10, 25, and 50 microM) and time- (12, 24, and 48 hr) dependent cytotoxicity, while Cremophor caused cytotoxicity only at high concentrations and long incubations. We conclude that (1) CsA is directly toxic to renal parenchymal cells in vitro and this system potentially represents a sensitive model for further mechanistic studies; (2) CsA plus vehicle (Sandimmune) was more cytotoxic to renal cells than CsA alone (without the polyoxyethylated castor oil vehicle).
Diffusion coefficients in trimethyleneoxide containing comb branch polymer electrolytes

Abstract This paper reports on a new comb branch polymer based on trimethylene oxide (TMO) side chains as a polymer electrolyte for potential application in lithium metal rechargeable batteries. The trimethylene oxide (TMO) units are attached to the side chains of a polyepoxide ether to maximize the segmental motion. Lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) salt was used to formulate the polymer electrolyte with the new TMO containing polymers. The new polymer electrolytes show improved salt diffusion coefficients ( D s ) and conductivity at ambient and subambient temperature compare to the ethylene oxide (EO) counterpart, whereas performance at high temperature (85 °C) remains the same or is actually worse for salt diffusivity.
Neurophysiological activity and toxicity of pyrethroids derived by addition of methylene, sulfur or oxygen to the chrysanthemate 2-methyl-1-propenyl substituent

Abstract Conversion of chrysanthemates to their cyclopropane, episulfide, and epoxide derivatives by addition of methylene, sulfur, or oxygen, respectively, to the 2-methyl-1-propenyl double bond yields products generally of reduced toxicity but enhanced neurophysiological activity and photostability. The reduced toxicity is established with cis-cyphenothrin derivatives administered intracerebrally to mice and topically to house flies and with cis-phenothrin derivatives applied topically to American cockroaches and house flies, even in the presence of piperonyl butoxide for the house flies. In contrast, cyclopropane, episulfide, and epoxide derivatives of phenothrin are more potent than the parent compound in eliciting repetitive firing following stimulation of a cercal sensory nerve of the American cockroach in vitro. The individual 1′R and 1′S isomers of epoxides derived from (1R,cis,αS)cyphenothrin, (1R,cis)phenothrin, and (1R,trans)tetramethrin differ in potency by up to 20-fold for insecticidal activity, >30-fold for intracerebral toxicity to mice, and ∼100,000-fold in the cercal sensory nerve assay. In each case the epoxide isomer of higher Rf is more potent than that of lower Rf when derived from a trans-chrysanthemate and vice versa from a cis-chrysanthemate.
The Use of Electric Circuit and Sound Signal in Determining the Albumen Height of Eggs

Abstract Albumen height has been reported as an objective measure of egg quality by Heiman and Carver (1936) and Wilgus and Van Wagenen (1935). Indirectly, albumen height is used to determine egg grades and has been adapted by Haugh (1937) for scoring the interior quality of eggs which is used as the basis for many quality control programs. The height of the albumen is measured in millimeters using a tripod micrometer with direct reading dial as shown in Figure 1. This type of instrument has been used for a considerable length of time, therefore has become standardized by the egg industry. In the process, the egg is broken on a flat surface, the tripod is placed over it, and the measuring rod is adjusted downward until the rod touches the albumen. The critical point occurs just as it touches, but it is difficult to observe this juncture quickly. With several hundred…
Output feedback variable structure control design for a class of uncertain linear systems

A dynamic output feedback variable structure controller for linear systems with mismatched uncertainties is studied. The proposed controller consists of nonlinear and linear parts. The linear part with full dynamics completely handles mismatched uncertainties and on the other hand, the nonlinear part is simplified as possible. By using the Lyapunov theory and linear matrix inequality method, the condition of existence of dynamic output feedback variable structure control law is derived and transformed as the feasibility problem described by linear matrix inequality, which can be solved by Matlab LMI toolbox to obtain the variable structure control for a class of system. A simulation example is given to illustrate that the analysis method and the result are valid and feasible.
Design and Operating Experience with Electronic Systems for High Rate Liquid Argon Calorimeters

A number of experiments have been instrumented by an ADC scheme utilizing an integrated amplifier, a packaged delay line, the difference of two samples taken Before and After the signal exits the delay, and a multiplexer to a single ADC for a system. This paper discusses design features, operating peculiarities, and experience to date.
Restraint of Fgf8 signaling by retinoic acid signaling is required for proper heart and forelimb formation

Cardiomelic or heart-hand syndromes include congenital defects affecting both the forelimb and heart, suggesting a hypothesis where similar signals may coordinate their development. In support of this hypothesis, we have recently defined a mechanism by which retinoic acid (RA) signaling acts on the forelimb progenitors to indirectly restrict cardiac cell number. However, we still do not have a complete understanding of the mechanisms downstream of RA signaling that allow for the coordinated development of these structures. Here, we test the hypothesis that appropriate Fgf signaling in the cardiac progenitor field downstream of RA signaling is required for the coordinated development of the heart and forelimb. Consistent with this hypothesis, we find that increasing Fgf signaling can autonomously increase cardiac cell number and non-autonomously inhibit forelimb formation over the same time period that embryos are sensitive to loss of RA signaling. Furthermore, we find that Fgf8a, which is expressed in the cardiac progenitors, is expanded into the posterior in RA signaling-deficient zebrafish embryos. Reducing Fgf8a function in RA signaling-deficient embryos is able to rescue both heart and forelimb development. Together, these results are the first to directly support the hypothesis that RA signaling is required shortly after gastrulation in the forelimb field to temper Fgf8a signaling in the cardiac field, thus coordinating the development of the heart and forelimb.
Translational molecular diffusion in phospholipid monolayers : substrate coupling and phase transitions

The results of an investigation of the phases of a monolayer of the phospholipid dipalmitoylphosphatidylcholine, deposited by Langmuir-Blodgett techniques onto hydrocarbon-derivatized silicon substrates, are described Measurements of the long-range translational diffusion of fluorescent lipid analogs in such monolayers reveal the presence of a phase transition not previously seen in phospholipids. It is marked by a large increase of lipid mobility at a temperature characteristic of the employed combination of lipid and substrate-attached hydrocarbon residue. A second transition into a high temperature phase, characterized by a rapid, homogeneous diffusivity, is observed at a temperature slightly above the temperature of the so-called chain melting transition in hydrated multi-bilayers of the lipid. In the novel intermediate state between the two transitions, long-range translational diffusion in the uniformly fluorescent monolayers is best described in a manner analogous to transport in composite materials. Lipid analogs containing a fluorophore in the polar headgroup portion of the molecule sample coexisting populations of host lipid whose diffusivities differ by as much as an order of magnitude in this temperature range. A chain labelled lipid analog is found to exhibit completely different behaviour, remaining largely immobile on the scale of the experimental observation times at temperatures below 43 °C. In samples cycled through the high temperature phase, this label exhibits increased mobilities at lower temperatures for several hours before returning to its original state. The measured diffusivities are compared with corresponding values obtained for monolayers spread at the air-water interface for which the average density is fixed, and also with available data for hydrated multibilayers. In natural bilayer membranes the two monolayer leaflets are generally not identical. They thus exhibit the same type of asymmetry as the one inherent in the system described here.
Dissolution Testing of Ibuprofen Tablets

AbstractDissolution testing (using three different methods, USP, FDA and a suggested method) was performed on eight different brands of commercially available ibuprofen tablets as purchased and also after storage at 37 C and 75% Relative humidity. Two dissolution values were determined at time 15 and 30 minutes.Statistical interpretation was performed using a Student's t test and Duncan multiple range test with an ANOVA on a SAS program.Some batches tested, notably, sugar coated tablets appeared to be particularly sensitive to the storage conditions used in this study and concern may be felt about possible loss of clinical efficacy. Of the three dissolution testing methodologies, the present USP method was the least discriminating, the FDA method was intermediate and the new proposed method was the most discriminating.
Fully automated microcomputer calculation of vibrational spectra

A fully automated method for computing frequencies and atomic displacements of normal modes, giving synthetic infrared and Raman spectra, has been developed for use on small computers. No expertise in group theory or the mathematics of normal-mode calculation are required to use the computer program. The method takes full account of symmetry and is applicable to any crystal or molecule. Force constants can be specified in terms of any two-atom “bonds” or three-atom angles. The essential steps in the computer program are: (1) Locate all atoms in the unit cell or molecule and compute displacement vectors for each internal coordinate; (2) Convert the basis of the force constants from bonds and angles to cartesian displacements; (3) Construct the full-matrix irreducible representations of the point or factor group in question, using appropriate symmetry matrices and polynomial basis functions; (4) Derive the symmetry coordinates in terms of cartesian displacements using the projection/transfer-operator technique; (5) construct secular equations for each species with Wilson's f–g method; (6) solve for frequencies and atomic motions; and (7) use simple models of infrared and Raman intensities to calculate spectra.
An online prepurchase intentions model

Abstract In this study, an Online Prepurchase Intentions Model is proposed and empirically tested in the context of search goods. The focus of this research is to determine whether intent to search the Internet for product information is a key element for marketing researchers to employ in predicting consumers’ Internet purchasing intentions. Data were collected through a mail survey to computer users who resided in 15 U.S. metropolitan areas. Two-stage structural equation modeling was employed to test hypotheses. The results show that intention to use the Internet to search for information was not only the strongest predictor of Internet purchase intention but also mediated relationships between purchasing intention and other predictors (i.e., attitude toward Internet shopping, perceived behavioral control, and previous Internet purchase experience). Direct and indirect relationships between two antecedents (attitude toward Internet shopping and previous Internet purchase experience) and Internet purchase intention were also found. Theoretical and managerial implications are discussed.
Laryngeal videostroboscopy in the dog model: a simplified technique and applications

Laryngeal videostroboscopy (LVS) allows the physician to examine the vibratory free edge of the vocal fold providing direct visualization of the vocal fold surface and indirect visualization of the substance of the vocal fold. Previously in dog LVS, electrical stimulation of the superior and recurrent laryngeal nerves or painful stimuli in the lightly anesthetized animal provided the impetus for glottic closure. In this paper we present a new technique for LVS in the dog model that involves mechanical traction on arytenoid adduction sutures to achieve vocal fold adduction. This method is safe, effective, and reproducible, and the potential applications are numerous.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Large inclusions in receptor cells of the amphibian lateral line.

With few exceptions, anatomical studies of amphibian lateral line systems have been limited to gross and light microscopic investigations. The lateral line of Xenopus laevis had been studied at the fine structural level, but electron microscopic data are available only for late larval and adult stages. A comparison of the ultrastructure of lateral line receptor cells at different stages in the life histories of urodele species indicates that four categories of large (to 3 μ diameter) organelles occur in these animals. Apical and synaptic dense bodies are morphologically similar but lie at opposite ends of the cell. Lysosomes and multivesicular bodies are concentrated in regions of the Golgi apparatus. Previously undescribed perinuclear crystalline inclusions seem to be associated with bundles of microfilaments. Inclusions of similar internal structure also occur within the nucleus. The location of a crystalline structure in the nucleus makes the definition of a more typical nucleolus mandatory.
Developing a methodology for assessing safety programs targeting human error in aviation

There is a need to develop an effective methodology for generating and evaluating interventions for reducing accidents due to human error. In this study, the Human Factors Intervention Matrix (HFIX...
Abandoning Sverdrup's Critical Depth Hypothesis on phytoplankton blooms

The Critical Depth Hypothesis formalized by Sverdrup in 1953 posits that vernal phytoplankton blooms occur when surface mixing shoals to a depth shallower than a critical depth horizon defining the point where phytoplankton growth exceeds losses. This hypothesis has since served as a cornerstone in plankton ecology and reflects the very common assumption that blooms are caused by enhanced growth rates in response to improved light, temperature, and stratification conditions, not simply correlated with them. Here, a nine-year satellite record of phytoplankton biomass in the subarctic Atlantic is used to reevaluate seasonal plankton dynamics. Results show that (1) bloom initiation occurs in the winter when mixed layer depths are maximum, not in the spring, (2) coupling between phytoplankton growth (l) and losses increases during spring stratification, rather than decreases, (3) maxima in net population growth rates (r) are as likely to occur in midwinter as in spring, and (4) r is generally inversely related to l. These results are incompatible with the Critical Depth Hypothesis as a functional framework for understanding bloom dynamics. In its place, a ''Dilution-Recoupling Hypothesis'' is described that focuses on the balance between phytoplankton growth and grazing, and the seasonally varying physical processes influencing this balance. This revised view derives from fundamental concepts applied during field dilution experiments, builds upon earlier modeling results, and is compatible with observed phytoplankton blooms in the absence of spring mixed layer shoaling.
Pulmonary mixed-function oxidation: stimulation by glucose and the effects of metabolic inhibitors

Abstract Substrate requirements for pulmonary mixed-function oxidation of p -nitroanisole to p - nitrophenol were evaluated using the isolated perfused rabbit lung and a lung microsomal fraction. Addition of glucose (5 mM) to the lung perfusate (Krebs bicarbonate buffer) increased the mean rate of p -nitroanisole oxidation by 25–55 per cent; addition of pyruvate (5 mM) or palmitate (0.5 mM) gave similar results. Sucrose (5 mM) had no effect. Antimycin A, KCN, oligomycin and bis-hexafluoroacetonyl acetone (an uncoupling agent) markedly depressed p -nitroanisole metabolism by the isolated lung. KCN also inhibited p - nitroanisole metabolism by lung microsomes, but antimycin A was without effect. These results indicate that pulmonary mixed-function oxidation requires substrate for intermediary metabolism as well as ATP, for maintenance of maximal rates. Glucose and mitochondrial substrates are equally effective in providing the energy requirements and the reducing potential for this reaction.
Static load classification for improving the value predictability of data-cache misses

While caches are effective at avoiding most main-memory accesses, the few remaining memory references are still expensive. Even one cache miss per one hundred accesses can double a program's execution time. To better tolerate the data-cache miss latency, architects have proposed various speculation mechanisms, including load-value prediction. A load-value predictor guesses the result of a load so that the dependent instructions can immediately proceed without having to wait for the memory access to complete. To use the prediction resources most effectively, speculation should be restricted to loads that are likely to miss in the cache and that are likely to be predicted correctly. Prior work has considered hardware- and profile-based methods to make these decisions. Our work focuses on making these decisions at compile time. We show that a simple compiler classification is effective at separating the loads that should be speculated from the loads that should not. We present results for a number of C and Java programs and demonstrate that our results are consistent across programming languages and across program inputs.
Mortality and morbidity with outpatient anesthesia: the Massachusetts experience.

All 147 active members of the Massachusetts Society of Oral and Maxillofacial Surgeons responded to an anesthesia survey. They had treated 416,561 patients during 1989. This article reports the results of the survey and specific untoward anesthetic events as recalled by these practitioners. Use of various anesthetic agents in 1989 and 1984 are compared.
Use of Serial Casting in the Management of Knee Joint Contractures in an Adolescent with Cerebral Palsy

Treatment of adolescents with cerebral palsy often presents clinical problems that differ from those encountered when treating younger children with cerebral palsy. Muscle contractures, which may not yield to traditional therapeutic exercise, may be a problem. The purpose of this case report is to describe the use of serial casting in the treatment of knee joint flexion contractures in an adolescent with cerebral palsy.
Life at the Top: The Transition State of AChR Gating

Most neurotransmitter receptors belong to either the pentameric nicotinoid receptor family or the tetrameric glutamatergic receptor family. The muscle nicotinic acetylcholine receptor (AChR), the prototype of the nicotinoid receptor family, gates by switching between a closed configuration (in which ion permeation is forbidden) and an open configuration (which allows ions to pass through). Rate-equilibrium linear free energy relationship analysis has allowed us to explore the transition state that links these two stable conformations. A series of point mutations were made to individual AChR residues, and the ensuing changes in the rate constants of channel opening and closing for the fully liganded receptor were determined. These experiments suggest that gating occurs approximately as a reversible, solitary conformational wave that propagates between the neurotransmitter binding site and the membrane domain, along the long axis of the receptor. A detailed knowledge of the gating mechanism can serve as a basis for understanding the shape of the postsynaptic ion current and for the differences in synaptic responses among different ligand-gated channels.
A Shocking Experience Ionic Modulation of Virtual Electrodes in Defibrillation

The discovery of defibrillation in 1899 by Prevost and Battelli1 has left us one of the most exciting clinical and research puzzles of the 20th century despite the obvious success of this treatment for arrhythmias. Initially, the idea of arresting ventricular fibrillation by the application of electric shock had seemed too fantastic even for Wiggers et al,2 whose research at Western Reserve University had laid the foundation for the first clinical application of defibrillation by Beck et al.3 During the last 2 decades of the 20th century, we witnessed clinical recognition and widespread application of implantable cardioverter-defibrillators (ICDs), which were stimulated in part by growing concern regarding the potentially harmful effects of antiarrhythmic drugs.4 Yet compelling evidence has been presented that pharmacological therapy combined with ICD therapy could decrease the frequency of shocks and improve the quality of life.5 Unfortunately, a lack of understanding of the ionic mechanisms of defibrillation impedes formulation of basic pharmacological strategies of defibrillation and redefinition of the role of antiarrhythmic drugs.4 The study by Cheek et al6 in this issue of Circulation Research presents one of the first attempts to build the basic science bridge between pharmacological and nonpharmacological therapies to control arrhythmias. Many investigators during the 20th century were puzzled by the mechanisms of defibrillation. Unfortunately, the inability of existing …
A method for simulating a flux-locked DC SQUID

The authors describe a computationally efficient and accurate method for simulating a DC superconducting quantum interference device's (SQUID's) V- phi (voltage-flux) and I-V characteristics which has proven valuable in evaluating and improving various SQUID readout methods. The simulation of the SQUID is based on fitting of previously acquired data from either a real or a modeled device using the Fourier transform of the V- Phi curve. This method does not predict SQUID behavior, but rather is a way of replicating a known behavior efficiently with portability into various simulation programs such as SPICE. The authors discuss the methods used to simulate the SQUID and the flux-locking control electronics, and present specific examples of this approach. Results include an estimate of the slew rate and linearity of a simple flux-locked loop using a characterized DC SQUID. >
Altruism Born of Suffering: How Colombian Human Rights Activists Transform Pain Into Prosocial Action

This study examines the impetuses for altruistic behavior of Colombian human rights activists, all of whom experienced politically based trauma. Thirty-five human rights activists participated in individual interviews conducted between 1998 and 2009. Results of the analysis are illustrated in nine themes: affirmation of self despite fear, indignation, a search for meaning, spirituality, justice to build peace, leaving a legacy of peace and agency for the next generation, support by others, and recognition and equity for ethnic minorities and for women. It is the hope of the author that these results contribute to the examination of how healing and altruism endure even in times of civil conflict and often as a result of such times, all of which ultimately leads to the betterment of community life.
Cross Regulation in Signaling Networks: A FRET Study of the PhoB-PhoR Two-Component System in E-Coli

The signal for the PhoR-PhoB two-component regulatory system of E. coli is environmental inorganic phosphate (Pi). A signal for environmental Pi insufficiency is propagated across the membrane to the cytosolic domain of the signalling histidine kinase PhoR via the ABC (ATP-binding cassette) transporter, the Pst (Pi-specific transport) system, in the absence of transport by protein-protein interactions, both in the membrane and the cytoplasm of the cell. Cross regulation also exists between PhoR-PhoB two-component system and key regulatory systems in E. coli, including the ArcB-ArcA two-component system for redox signalling. Such cross regulation among key signalling systems is thought to be important for integration of diverse cellular pathways in the control of cell growth and for survival under conditions of stress. Knowledge of how these interactions is brought about necessary to understand fully the dynamics of the response of the Pi signalling network to environmental Pi insufficiency and to understand interactions of the PhoR-PhoB and other signalling systems. Here we have employed Forster resonance energy transfer (FRET) techniques (acceptor photobleaching and sensitized emission) coupled with specific knock-out mutants to investigate in live E. coli cells interactions between ECFP-labelled members of the PhoR-PhoB system and protein targets with which they are thought to interact such as the o-succinylbenzoyl-CoA synthase, MenC. We will show a strong enhancement of the FRET signal through the use of protein fusions and knock-out mutants. We will discuss results of this study in terms of their implication on the dynamics of the PhoR-PhoB two-component signal transduction system.
Endocrinology of Aging

1. Thyrotropic-Axis Adaptations in Aging and Chronic Disease (Morris) 2. Perimenopausal Reproductive Endocrinology (Burger), Hale, Dennerstein and Robertson) 3. Osteopenia of Male Aging (Khosla and Riggs) 4. Mechanisms of Premature Menopause (Rebar) 5. Relative Testosterone Deficiency in Older Men: Clinical Definition and Presentation (Wang) 6. Sarcopenia of Male Aging (Nair) 7. Insights into Physiological Mechanisms of Relative Hypogonadism (Liu and Veldhuis) 8. IGFBP Adaptations (Frystyk and Orskov) 9. Utility of Ultrasensitive GH Assays in Aging-Related Hyposomatotropism (Iranmanesh) 10. Sex-Steroid Control of Aging GH Axis (Veldhuis and Miles) 11. GH Secretagogue Use in Older Adults (Bowers) 12. Testing Pituitary Function in Aging Individuals (Ghigo) 13. Corticotropic-Adrenal Axis In Aging (Chrousos and Vgantzas)
Effects of Turbidity on Prey Consumption by Prairie Stream Fishes

Abstract Reduced suspended-sediment loads (i.e., turbidity) in many Midwestern prairie rivers have been hypothesized as contributing to the replacement of species that historically occupied highly turbid main-channel habitats by visually feeding species that are competitively superior in less-turbid waters. We examined the relationship between prey consumption and turbidity for six fish species from the Canadian River (New Mexico, Oklahoma, and Texas) and found experimental support for this hypothesis. Among species adapted to highly turbid main-channel habitats, we found that prey consumption by the peppered chub Macrhybopsis tetranema and flathead chub Platygobio gracilis was unaffected (P > 0.12) by elevated turbidity, whereas prey consumption by the Arkansas River shiner Notropis girardi was reduced (P < 0.01). Among species characteristic of less-turbid habitats, prey consumption by the emerald shiner N. atherinoides, red shiner Cyprinella lutrensis, and sand shiner N. stramineus was reduced (P < 0.0...
Inside Cover: A Phosphine‐Mediated Conversion of Azides into Diazo Compounds (Angew. Chem. Int. Ed. 13/2009)

In 1919 H. Staudinger and J. Meyer reported the reductive fragmentation of an azide to an amine. In their Communication on page 2359 ff., E. L. Myers and R. T. Raines report the complementary reaction—cleavage of the other NN bond in an azide to yield a diazo compound. Both transformations rely on a reagent that contains PIII. The painting, The Alchymist, in Search of the Philosopher's Stone, Discovers Phosphorus, by J. Wright (1771), depicts the discovery of phosphorus by H. Brandt in 1669 (cover art by H. A. Steinberg).
Power requirements and mechanical efficiency of treadmill walking

Abstract The instantaneous energy levels of body segments are computed from kinematic measurements on a level treadmill at various speeds with freely chosen step rates and a constant speed with different imposed step rates. The changes in the energy levels of segments are combined to compute the average work rate required to accelerate the total body (positive internal work). This work is compared to total metabolic power consumption to obtain a minimal estimate of mechanical efficiency. The efficiency increases rapidly from 9% to 0.84 m/sec to a maximum of 23% at 1.70 m/sec. Thereafter, the efficiency slowly decreases with speed to 18% at 2.35 m/sec. When different step rates are imposed at one constant speed, the average positive work rate remains constant. This work rate level is identical to that required for walking at the same speed with self-determined (free) step rate. Thus, maximum gross efficiency results at the free step rate.
Understanding the dynamics of rapidly evolving pathogens through modeling the tempo of antigenic change: influenza as a case study.

article i nfo Rapidly evolving pathogens present a major conceptual and mathematical challenge to our understanding of disease dynamics. For these pathogens, the simulation of disease dynamics requires the use of computational models that incorporate pathogen evolution. Currently, these models are limited by two factors. First, their computational complexity hinders their numerical analysis and the ease with which parameters can be statistically estimated. Second, their formulations are frequently not sufficiently general to allow for alternative immunological hypotheses to be considered. Here, we introduce a new modeling framework for rapidly evolving pathogens that lessens both of these limitations. At its core, the proposed framework differs from previous multi-strain models by modeling the tempo of antigenic change instead of the pathogen's genetic change. This shift in focus results in a new model of reduced computational complexity that can accommodate different immunological hypotheses. We demonstrate the utility of this antigenic tempo model in an application to influenza. We show that, under different parameterizations, the model can reproduce the qualitative findings of a diverse set of previously published flu models, despite being less computationally intensive. These advantages of the antigenic tempo model make it a useful alternative to address several outstanding questions for rapidly evolving pathogens.