cssi/SciSciGPT-SciSciNet huggingface dataset:
Debugging in Distributed Systems

Debugging sequential programs on a uniprocessor is a fairly well-understood task. A good interactive debugger supports breakpoints and single-step execution for a line-by-line analysis of the effect of procedures and instructions on program state, all in the context of the original source code. At any moment in time, the user can halt execution and examine any aspect of the program's state, tracing the relationship between source code and error symptoms at whatever level of detail desired. Distributed systems, on the other hand, introduce enormous complications for debugging. The physical separation of processors and the communication delays between processors make halting all processors instantaneously impossible. There are properties that adds a dimension to the problem of debugging that is not present with sequential programs. Perhaps the greatest difficulty stems from the uncertainty present in any system with unpredictable communication delays. Any debugging technique that requires use of the processors or communication medium can introduce these delays, and obscure the true execution being observed. Distributed systems require debugging techniques that explicitly address the uncertainty inherent in distributed systems. Not all queries are possible, especially queries that require the debugger to know something about the state of two different processors at the same precise moment in time. In fact, distributed systems require a new notion of time, where time is relative to the processor making the observation. In addition, since a distributed program is made up of many sequential programs, distributed systems need an expanded notion of program state and the events that cause changes in that state. Distributed systems also need new techniques for monitoring program executions and new debugging tools that allow for examination of the execution state and interact with a program in execution. In a distributed system, processes communicate by exchanging messages. Therefore, message operations are the primary events of interest during debugging. There are several techniques that can be used to monitor execution and recognize the occurrence of message events. During the debugging cycle, the debugger and user interact to find the source of errors. The debugger captures execution information and presents it to the user; the user analyzes the information, makes hypotheses, initiates experiments, and requests more information. Thus, the way in which the debugger presents information to the user is crucial. As with any software system, there are a variety of ways to present information to the user. Despite the many advances made since 1985 or so, distributed program debugging remains a difficult problem. Problems (among others) will be the focus of research efforts, while users continue to gain valuable experience with the techniques already developed. Keywords: debugging; event recognition; time; distributed systems; halting execution; breakpoints; open problems; user interface
Study of the mechanisms of hydrogen peroxide and hydroxyl free radical-induced cellular injury and calcium overload in cardiac myocytes

There is evidence that myocardial injury, as would occur on post-ischemic reperfusion, may be caused by the generation of oxygen radicals, as well as by the induction of intracellular calcium overload; however, the relationship between these two mechanisms of injury is not known. To test the hypothesis that oxidants and oxygen radicals can cause cardiac myocyte injury and intracellular calcium overload, isolated adult rat ventricular myocytes were exposed to H2O2 (1-10 mM) and Fe3(+)-nitrilotriacetate. EPR measurements confirmed the production of the highly reactive .OH radical by this system. The oxygen radical generating system initially caused a transient augmentation of twitch amplitude in single field stimulated myocytes. This was followed by contractile oscillations occurring during the twitch prior to full cell relaxation, and spontaneous mechanical oscillations occurring between electrically stimulated contractions. Eventually, cells became inexcitable and abruptly underwent contracture. In the presence of lower bathing calcium concentrations, these oxidant-induced alterations were prevented or delayed. However, cells exposed to the radical generating system in the absence of extracellular calcium still eventually underwent contracture but stimulated contractions or mechanical oscillations were not seen. Measurements in single myocytes loaded with the fluorescent probe of intracellular calcium, Indo-1, demonstrated a rise in both systolic and diastolic fluorescence ratio, as well as oscillations and widening of the fluorescence transient, suggestive of cellular calcium loading, following exposure to the radical generating system. Injured myocytes did not take up trypan blue dye. Contractile dysfunction and calcium channel blocker, nitrendipine. NMR measurements of cellular [ATP] demonstrated that these alterations in cellular calcium preceded the depletion of ATP. Subsequent depletion of ATP was accompanied by the appearance of increased concentrations of sugar phosphates indicative of a block in glycolysis and ATP depletion correlated with cellular rigor. Thus, oxygen free radicals can cause cardiac myocyte injury with contractile abnormalities which occur due to myocyte calcium loading. The mechanism of oxidant-induced calcium loading is not due to nonspecific membrane damage, or energy depletion, but rather due to increased calcium influx through voltage gated calcium channels. This early calcium overload state as well as oxidant induced block of glycolysis result in cellular energy depletion and cell death with the induction of contracture.
β-Lactam Antibiotics

The β-lactam antibiotics are a large class of diverse compounds used clinically in both the oral and parenteral forms. The β-lactam antibiotic agents have become the most widely used therapeutic class of antimicrobials because of their broad antibacterial spectrum and excellent safety profile. Reports of drug-drug interactions with the β-lactam antimicrobials are a relatively rare phenomenon, and when interactions do occur, they are generally minor. This chapter describes the drug-drug interactions of the β-lactam antibiotics: penicillins, cephalosporins, carbapenems, and monobactams.
A compositional framework for real-time embedded systems

While component technology has been widely accepted as a methodology for designing complex systems, there are few component technologies that have been developed to accommodate the characteristics of embedded systems. Embedded systems are often subject to resource constraints as well as timing constraints. Typical scarce resources include memory for cost-sensitive systems. Many techniques, developed for reducing code size, often yield code size vs. execution time tradeoffs. Our goal is to develop a framework for supporting the compositionality of resource and timing properties. The proposed framework allows component-level resource and timing properties, which include the resource/time tradeoffs, to be independently analyzed, abstracted, and composed into the system-level resource and timing properties. In this paper, we focus on the problem of composing the collective task-level code size vs. execution time tradeoffs into a component-level code size vs. execution time tradeoff.
Remarks by Commentating Editor

Years ago, when we first started this journal we were the new kids on the block; uncertain about the response of the criminology community and our place in the academic world. However, we were clea...
Postnatal Selenium Repletion Protects Lungs of Neonatal Rats from Hyperoxia

We reported previously that Se-adequate neonatal rat pups born to Se-adequate dams were resistant to lung damage by hyperoxia. To assess whether early postnatal Se repletion could also protect developing pups reared under hyperoxia, female Sprague-Dawley rats (n = 20) were bred and fed a Se-deficient (0.04 microgram/g) diet during pregnancy. On d 1 postpartum, dams were divided into two groups and fed either a Se-deficient diet or a Se-repleted (0.5 microgram/g) diet. On d 4 postpartum, litters in each group were randomly assigned to either air or high oxygen (greater than 95% O2) environments. Histologic evaluation of lungs from d-8 pups indicated that Se repletion significantly reduced the incidence of lung lesions caused by hyperoxia. Selenium-repleted pups also had significantly greater lung volumes and internal surface areas. The 7-d period of Se repletion resulted in significantly elevated maternal milk Se concentrations compared with a Se-deficient group, which was reflected in the pups by elevated plasma and hepatic Se concentrations and Se-dependent glutathione peroxidase (SeGPx) activities. Pulmonary glutathione concentration and SeGPx activity in pups were affected by oxygen exposure only, not by Se nutrition. Therefore, early postnatal Se repletion can protect the developing lung from oxygen-induced injury, a protection that is not entirely due to the effects of Se on pulmonary SeGPx activity and glutathione concentration.
Amplification of Single-Walled Carbon Nanotubes from Designed Seeds: Separation of Nucleation and Growth†

Single-walled carbon nanotubes (SWNTs) may be grown from designed seeds containing an SWNT and the catalyst required for continued growth. Dodecyl side-walled functionalized SWNTs (DD-SWNTs) are end-functionalized with 4-hydroxypyridine via dicyclohexylcarbodiimide coupling to allow covalent coordination of an inorganic cluster pro-catalyst (FeMoC). DD-SWNT-py-FeMoC on spin-on glass was exposed to H2/CH4 at 800 °C, resulting in 3-fold growth in the length of 40% of the seed SWNTs. Only ∼1% of the procatalyst alone nucleate SWNTs under the same conditions, suggesting effective separation of the nucleation and growth processes.
The effects of boron in TiAl/Ti3Al

Abstract The TiAl/Ti 3 Al interfacial misfit dislocations structures were investigated by TEM in Ti-45Al alloy and Ti-45Al/TiB 2 composite. For TiAl with c/a = 1.02, only a single set of misfit dislocation arrays are crystallographically possible; these were observed in Ti-45Al alloy. However, the observation of three sets of misfit dislocation arrays in the Ti-45Al/TiB 2 composite suggests that the occupation of octahedral sites in the TiAl structure by excess boron was responsible for a decrease in the c/a ratio leading to an increased fcc character of the TiAl at the TiAl/Ti 3 Al interface.
Variability in reader selection of subtle cases for inclusion in a reduced size receiver operating characteristic (ROC) study

Sample size in ROC studies may be significantly reduced by including only difficult cases in the image set, but variability across studies may be a possible obstacle in the development of such a methodology due to case selection. To assess this situation, 300 cases used in a previous large ROC study, which included nine observers, were independently classified as subtle or typical by two experienced readers. Data from the previous study were reanalyzed using data sets consisting only subtle or typical images as designated by each classifier. Results showed a marked decrease in observer performance from the original study's results when only the subtle cases of either classifier were included in the analyses. For 12 of 15 possible comparisons (3 imaging modes and 3 diseases for subtle cases of either classifier were included in the analyses. For 12 of 15 possible comparisons (3 imaging modes and 3 diseases for subtle cases, 3 modes and 2 diseases for typical cases), the Spearman rho correlation coefficient between the performance indices computed for each reader for the subsets classified as subtle and typical was high and significant (P < 0.05). The results obtained in this preliminary study are encouraging and point out areas that warrant further investigation.
Linearity of research design in ethnographic studies of speaking

“Linearity” in the design and conduct of research refers to the specification, in advance of data collection, of both a purpose for research and of the steps to be taken to serve the purpose. The requirements of naturalistic inquiry can make it difficult to design and conduct research according to the standards of linearity which are implicitly or explicitly reflected in scientific inquiry in speech communication. Ethnographies of speaking, one variety of naturalistic inquiry, are exemplary of this difficulty, but a consideration of how ethnographers can and do follow a standard of linearity in research design and conduct suggests that the difficulty is surmountable.
Teleoncology: current and future applications for improving cancer care globally

Summary Access to quality cancer care is often unavailable in low-income and middle-income countries, and also in rural or remote areas of high-income countries. Teleoncology—oncology applications of medical telecommunications, including pathology, radiology, and other related disciplines—has the potential to enhance access to and quality of clinical cancer care, and to improve education and training. Implementation of teleoncology in the developing world requires an approach tailored to priorities, resources, and needs. Teleoncology can best achieve its proposed goals through consistent and long-term application. We review teleoncology initiatives that have the potential to decrease cancer-care inequality between resource-poor and resource-rich institutions and offer guidelines for the development of teleoncology programmes in low-income and middle-income countries.
The contrasting effects of diphenylhydantoin and procaine amide on A-V conduction in the digitalis-intoxicated and the normal heart

Abstract The effects of diphenylhydantoin (DPH) and procaine amide on A-V conduction in the digitalis-intoxicated and the normal heart were compared. DPH consistently converted more acetylstrophanthidin-induced ventricular tachycardia to sinus rhythm and completely restored A-V conduction to control values. In contrast, procaine amide, in doses necessary to counteract digitalis-induced ventricular tachycardia, invariably exacerbated the A-V conduction prolongation produced by the glycoside. The effect of DPH on A-V conduction makes this a unique drug in the therapy of digitalis toxicity, since it abolishes both the ventricular ectopia and A-V conduction abnormalities produced by the glycoside. The selective effects of DPH are in contrast with agents such as procaine amide which depress both ventricular ectopia as well as A-V transmission in the digitoxic heart. However, DPH is contra-indicated in complete heart block.
No evidence that a common pesticide impairs female mate choice in a freshwater amphipod

Sublethal concentrations of pesticides may drastically alter the evolutionary trajectories of populations by interfering with mating behaviors. We used a median lethal concentration (LC50) experiment to test the sensitivity of three amphipod (Hyalella sp.) classes (females, small males, and large males) to five concentrations [10.4, 1.52, 0.16, 0.05, none detected (ND) μg/L] of the most commonly applied pesticide (malathion) in the United States. We then tested the sensitivity of female mate choice to sublethal concentrations (0.55, 0.38, and 0.05 μg/L) of malathion using a dichotomous choice test. Mortality was relatively high at low concentrations for all three amphipod classes with LC50s ranging from 0.06 μg/L in females to 0.19 μg/L in small males. There was overlap in the 95% CI of these estimates across amphipod classes suggesting no class-specific differences in sensitivity to malathion. We found no evidence that malathion interferes with female choice in this species, suggesting that mating behavior may not always be a good indicator of sublethal pesticide contamination. © 2009 Wiley Periodicals, Inc. Environ Toxicol 2010.
The politics of student alienation: the case of Iran

(1969). The politics of student alienation: the case of Iran. Iranian Studies: Vol. 2, No. 1, pp. 8-26.
Dual-Carrier Aggregation Receiver With Reconfigurable Front-End RF Signal Conditioning

A reconfigurable receiver that can support dual-carrier aggregation is demonstrated. Switched Capacitor (SC) technique is explored at the receiver front-end for direct RF signal conditioning. By changing the connections of the switches and capacitors, various filtering profiles, including bandpass and notch functions, can be synthesized. On the other hand, complex-domain signal processing enables RF selectivity with controllable offset frequency relative to the LO frequency. Therefore, multiple RF channels can be selected simultaneously by multiple complex-domain signal processors and a shared single front-end. The scheme also enables a 4th-order RF bandpass transfer function by combining two 2nd-order bandpass transfer functions with slightly different center frequencies. In this work, a combination of a reconfigurable front-end passive SC network and two concurrent complex-domain signal processors enables the receiver to handle different signal scenarios. A proof-of-concept CMOS chip fabricated in a 65 nm CMOS technology is presented that supports single-channel and dual-carrier aggregation receiving modes. The receiver covers the frequency range from 0.1 to 1 GHz. The frequency distance between two concurrent RF channels can be tuned anywhere between 0 to +100 MHz. The near-band blocker resilience is improved by 15 dB when the front-end is configured as a notch filter.
Synthesis, characterization, and molecular structure of the quadruply bonded ditungsten(ll) complex, W2Cl4(dppm)2

The reaction of W2Cl4[P(n-Bu)3]4 with bis(diphenylphosphino)methane (dppm) affords the highly air-sensitive material, W2Cl4(dppm)2, which has been characterized by IR and visible spectroscopy, and by X-ray crystallography. The compound crystallizes in the centrosymmetric space group C2/c with the following parameters: a = 17.298(3); b = 17.011- (2); c = 18.413(2) A; β = 98.93(2); V = 5352(2) A3; Z = 4. The molecule is positioned about a C2 axis which allows for a net torsion angle of 17.25° down the WW vector. This does not seem to significantly effect the WW bond distance (2.269(1) A) relative to other quadruply bonded ditungsten species.
Lower cretaceous sediments from the northwest pacific.

The first occurrence of deep-sea Lower Cretaceous (Albian) sediments in the Pacific Ocean is reported from the Shatsky Rise at 31°519N, 157°209E. Seismic-profile records indicate that the core was taken between the extensive seismic reflectors A and B. Two hundred meters of unconsolidated sediment lies between the core site and basement (B) and suiggests that the sediment just above basement may be at least as old as Middle Jurassic.
Interstellar diazenylium recombination and nitrogen isotopic fractionation

In an earlier paper (Charnley & Rodgers), we demonstrated that gas-phase chemistry in selectively depleted interstellar cores and/or protostellar discs can lead to significant 15 N enhancements. Recent laboratory measurements of the electron dissociative recombination of N 2 H + show that this reaction is able to break the N-N bond and so will release nitrogen atoms and NH radicals into the gas at a much faster rate than previous models have assumed. We have assessed the importance of this new result for the 15 N chemistry and find that the reaction acts to reduce the degree of 15 N enhancement. We discuss two modifications to our original model that each allow the high 15 N/ 14 N ratios to be recovered: N 2 H + recombination on polycyclic aromatic hydrocarbon (PAH) molecules and a small barrier in the N + NH reaction. We find that higher 15 N/ 14 N ratios can be produced in this revised model. Some observational consequences of these are outlined.
The Internet and Anti-War Activism: A Case Study of Information, Expression, and Action

This case study examines how traditional and Internet news use, as well as face-to-face and online political discussion, contributed to political participation during the period leading up to the Iraq War. A Web-based survey of political dissenters (N = 307) conducted at the start of the U.S.-led invasion of Iraq provides the data used to examine the relationships among informational media use, online and face-to-face political discussion, and political participation among the respondents, who were recruited through blogs, discussion boards, and listservs opposing the Iraq war. Analyses reveal that among these respondents, Internet news use contributed to both face-to-face and online discussion about the situation in Iraq. Online and face-to-face political discussion mediated certain news media effects on anti-war political participation. The study stresses the complementary role of Web news use and online political discussion relative to traditional modes of political communication in spurring political participation.
Covariates of Self-Efficacy Caregiver Characteristics Related to Mental Health Services Self-Efficacy

Increasingly, professionals are recognizing the need to involve parents and other caregivers in the mental health treatment of children. However, parents and caregivers may not feel efficacious whe...
Valproic acid treatment of experimental status epilepticus

Abstract The efficacy of valproic acid (VPA) in control of generalized convulsive status epilepticus was tested in a rat model. Rats with cortical cobalt lesions were injected with homocysteine thiolactone to induce secondarily generalized tonic-clonic seizures (GTCS). The median effective dose (ED 50 ) for control of GTCS was 211.9 mg/kg (270 μg/ml in serum 30 min post dose) when treatment was given intraperitoneally after the second GTCS. VPA entered both serum and brain very rapidly after injection, with little change in concentration from 5 to 30 min post dose. In earlier experiments with phenytoin, phenobarbital, diazepam and lorazepam in this model, we found that the serum concentrations produced by the ED 50 s versus GTCS were very similar to those which have been reported to be effective in treating human status epilepticus. If this same relationship holds true for VPA, we would predict that a serum concentration of around 270 μg/ml VPA would be required for control of generalized convulsive status epilepticus in human patients. The safety of this high a concentration of VPA has not been tested.
Determination of Ratio of Complex Eigenvalues of Optical Systems with Known Eigenpolarizations by Ellipsometry

Surface ellipsometry involves measurement of the ratio of eigenvalues (reflection coefficients) associated with the orthogonal linear eigenpolarization parallel and perpendicular to the plane of incidence. This paper shows that the ratio of complex eigenvalues of any optical system with known arbitrary eigenpolarizations can be determined, with equal ease, using the same ellipsometer arrangements of surface ellipsometry. Expressions are derived that give the ratio of eigenvalues as a function of (1) the Cartesian complex polarization variables that describe the eigenpolarizations, (2) a set of nulling angles in the symmetrical PC1SC2A or asymmetrical PCSA and PSCA ellipsometer arrangements, (3) the slow-to-fast complex relative transmittance of the compensator(s). The results are applied to the ellipsometric measurement of optical rotatory dispersion and circular dichroism.
Role of the initial growth mode on the dislocation structure in MBE grown ZnSe/GaAs(100)

Abstract We investigate the effect of manipulating the initial growth mode of ZnSe on GaAs(100) on the dislocation distribution and crystal quality of the epilayers. The growth mode is manipulated, from a three-dimensional to a two-dimensional one, by controlling the impinging sequence of source beam fluxes on Ga or As stabilized GaAs(100) surfaces. Through electron microscopy, photoluminescence, and Raman spectroscopy studies we find that an increasingly two-dimensional growth mode strongly improves crystal quality, and results in drastic reduction of threading dislocation densities. Growth of a 1 μm ZnSe layer under two-dimensional initial growth conditions results in a very low (fewx106 cm-2) threading dislocation density at the epilayer surface.
Temporal and spatial behavior of photon echoes stimulated from long pulses

Abstract To evaluate the coherent saturation effects of continuous optical processing using optical coherent transients we studied the time dependence of the photon echoes stimulated by probe fields with constant amplitudes and durations comparable to the coherent dephasing time. The propagation directions of the long echoes were also found to be different from brief pulse echoes. Echoes in the non-causal direction were predicted with a theory based on Maxwell–Bloch equations, observed experimentally, and explained analytically.
Resolution of pace mapping stimulus site separation using body surface potentials.

BACKGROUNDSeveral studies have related 12-lead ECG waveform during ventricular tachycardia to ECG waveform during ventricular pacing to identify ablation sites for therapy of ventricular tachycardia. QRS isopotential maps and QRS isointegral maps derived from body surface isopotential maps have also been correlated with left ventricular pacing sites with the same objective. The comparison process used is subjective and only semiquantitative. Improved accuracy of catheter placement may improve success rates of ablation therapy.METHODS AND RESULTSThis animal study was performed to determine the spatial resolution with which left ventricular pacing sites could be distinguished by body surface isopotential mapping. Potentials were recorded from 64 evenly spaced thoracic leads. Hexapolar or octapolar pacing catheters with 2-mm interelectrode spacing were placed percutaneously in the left ventricle in each of six dogs, and bipolar endocardial pacing was performed using each pair of adjacent electrodes. QRS isop...
Study on side-chain liquid–crystalline copolymer as a new β -nucleating agent to induce phase behavior of isotactic polypropylene

The nucleating activity of side-chain liquid–crystalline copolymer, as new β-nucleating agent (LCP-NA3), towards isotactic polypropylene (iPP) was investigated by differential scanning calorimetry, wide-angle X-ray diffraction, and polarized optical microscopy. The effect of LCP-NA3 content, crystallization temperature, and time on the phase behavior of the iPP has been discussed. The results indicate that the relative content of β-crystal mainly depends on LCP-NA3 content, crystallization temperature, and time. A high content of β-crystal can be obtained by the combined effect of the optimum LCP-NA3 concentration, crystallization temperature, and time. The maximum content of β-crystal reaches 0.63 when the LCP-NA3 content, crystallization temperature, and time are 0.8 wt%, 130 °C, and 1 h, respectively. In addition, LCP-NA3 is identified to have dual nucleating ability for α- and β-crystals under appropriate kinetic conditions.
Introduction: Immunopathology and the promise of stem cell research.

During the last few years, stem cell technology has elicited a great deal of fascination, hope and controversy as have done other cell research programs. The primary aim of developing stem cells for medical application is to regenerate tissues and repair failing organs. In addition, stem cell research can be viewed as a key to addressing and understanding many of the most fundamental and basic questions in clinical biology. A better insight into early cell development will provide answers to the question why cells behave abnormally and generate pathologies such as cancer or autoimmune and degenerative diseases. The huge interest focussing on this research and its potentially therapeutic applications are evident from the large investment made by companies, governments and universities worldwide. In October and November 2010, the two first human trials of cell therapy by embryonic stem cell-derived injections for spinal cord injury and non-hereditary forms of blindness were approved by the FDA. The source of stem cells, however, remains a subject of debate. Taking into account genetic and immunological criteria, stem cells can be derived from either of the following:
Comment on ''Molecule formation during sputtering by two-body associative ionization with diabatic curve crossing''

A Comment on the Letter by K. J. Snowdon, W. Heiland, and E. Taglaver, Phys. Rev. Lett. 46, 284 (1981).
First-class views: a key to user-centered computing

Large database systems (e.g., federations, warehouses) are multi-layer — i.e., a combination of base databases and (virtual or physical) view databases1. Smaller systems use views for layers that hide detailed physical and conceptual structures. We argue that most databases would be more effective if they were more user-centered — i.e., if they allowed users, administrators, and application developers to work mostly within their native view. To do so, we need first class views — views that support most of the metadata and operations available on source tables.First class views could also make multi-tier object architectures (based on objects in multiple tiers of servers) easier to build and maintain. The views modularize code for data services (e.g., query, security) and for coordinating changes with neighboring tiers. When data in each tier is derived declaratively, one can generate some of these methods semi-automatically.Much of the functionality required to support first class views can be generated semi-automatically, if the derivations between layers are declarative (e.g., SQL, rather than Java). We present a framework where propagation rules can be defined, allowing the flexible and incremental specification of view semantics, even by non-programmers. Finally, we describe research areas opened up by this approach.
The Influence of Metabolism on Percutaneous Absorption of Cyclosporin-A

AbstractOur previous reports using hairless mouse skin model showed that topical delivery of cyclosporin-A (CsA) could be achieved and controlled with nonionic liposomal and nonionic lipid-based formulations composed of glyceryl dilaurate (GDL), cholesterol (CH), and polyoxyethylene-10-stearyl ether (POE-10) at varying weight ratios (1,2). However, the distribution profiles were obtained using radiolabeled CsA and thus could represent intact drug as well as its metabolites. The present studies aim to investigate if the previously reported profiles actually represented intact CsA. The studies were carried out using a “high-pressure” liquid chromatography (HPLC) method and in vitro skin deposition studies with a metabolic inhibitor (sodium azide) incorporated in the receptor fluid. The results indicated that skin metabolism of CsA and hence its effect on percutaneous absorption of CsA is minimal and that the CsA distribution profiles obtained using radiolabeled CsA represented distribution of intact drug an...
Pharyngeal adaptation in Zenker's diverticulum : The faux pharyngoesophageal segment

Background We have noticed a protrusion on the pharyngeal wall in patients with Zenker's diverticulum (ZD). The protrusion gives the appearance of a neo-pharyngoesophageal segment (faux-PES) and may represent an adaptation to protect the airway. Study Design A case-control study. Methodology The fluoroscopic swallow studies of patients with ZD were compared with matched controls. Information regarding the presence and location of a faux-PES, true PES opening, pharyngeal constriction, and laryngohyoid elevation was compared. Results The fluoroscopic swallow studies of 31 patients with ZD were compared with 31 controls. A faux-PES was found in 100 percent of ZD patients and in 0 percent of controls. The mean maximum opening of the faux-PES was 1.5 (±0.27) cm. The faux-PES was located 1 cm above the true PES below the entrance to the supraglottic airway. This is the optimal location for airway defense. Conclusions The faux-PES was identified in 100 percent of patients with ZD. The faux-PES may represent a physiologic adaptation to protect the airway from regurgitation out of a ZD.
Self-assembled monolayers formed by 5,10,15,20-tetra(4-pyridyl)porphyrin and cobalt 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine on iodine-passivated Au(1 1 1) as observed using electrochemical scanning tunneling microscopy and cyclic voltammetry

Abstract Self-assembled monolayers (SAMs) of 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP) and cobalt 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine (CoTPyP) were formed by in situ equilibrium adsorption onto Au(1 1 1) electrodes passivated by an interposed adlayer of iodine. Adsorption of the porphyrins onto Au(1 1 1) was confirmed by cyclic voltammetry, and each of the SAMs was imaged using electrochemical scanning tunneling microscopy (EC-STM). The TPyP and CoTPyP SAMs were found to contain highly ordered domains on I–Au(1 1 1) at positive potentials where a disordered SAM would be expected for bare Au(1 1 1). Cyclic voltammetry was also used to observe in situ the assembly of binary SAMs containing TPyP and CoTPyP as they formed.
Intracellular Calcium Release at Fertilization in the Sea Urchin Egg

Abstract Fertilization or ionophore activation of Lytechinus pictus eggs can be monitored after injection with the Ca-sensitive photoprotein aequorin to estimate calcium release during activation. We estimate the peak calcium transient to reach concentrations of 2.5–4.5 μ M free calcium 45–60 sec after activation and to last 2 3 min, assuming equal Ca 2+ release throughout the cytoplasm. Calcium is released from an intracellular store, since similar responses are obtained during fertilization at a wide range of external calcium concentrations or in zerocalcium seawater in ionophore activations. In another effort to estimate free calcium at fertilization, we isolated egg cortices, added back calcium quantitatively, and fixed for observation with a scanning electron microscope. In this way, we determined that the threshold for discharge of the cortical granules is between 9 and 18 μ M Ca 2+ . Therefore, the threshold for the in vitro cortical reaction is about five times the amount of free calcium, assuming equal distribution in the egg. This result suggests that transient calcium release is confined to the inner subsurface of the egg.
6-mercaptopurine and spermatogenesis in the young rat

In recent years, 6-MP treatment has been beneficial in the treatment of inflammatory bowel disease (IBD). Since 6-MP and its metabolites interfere with various steps in nucleic acid biosynthesis, chronic use of 6-MP could theoretically alter normal cell turnover, including spermatogenesis. Therefore, we have investigated the effect of daily 6-MP administration on spermatogenesis in the young rat. 6-Mercaptopurine was administered in clinically relevant doses 24 and 40 mg/m2. Testicular weights of rats treated with 24 mg/m2 for 75 days or 40 mg/m2 for 25 days were not significantly different among 6-MP, pair-fed, orad libitum chow-fed groups. Quantitation of the stages of seminiferous tubules or the number of homogenization-resistant, mature spermatids per testis were not affected by 6-MP treatment. In addition, 6-MP had no effect on serum testosterone or on HCG-stimulated testosterone release by the testes. These results suggest that chronic low-dose 6-MP therapy, as used in the treatment of IBD, may not carry as great a risk for suppression of spermatogenesis as theorized. Our study in animals indicates that evaluation of 6-MP and spermatogenesis in man is warranted.
Stochastic Lorentz observers and the divergences in quantum field theory

Sharp space-time coordinatesx are replaced by stochastic space-time coordinatesX with meansx and dispersion measured by a universal lengthλ as the kinematical basis of Lorentz covariant field theories, classical or quantum. It is found that 4-dimensional distributions are not possible, but 3-dimensional (unsharp rods, sharp clocks) and 1-dimensional (unsharp clocks, sharp rods) distributions are allowed. We find that Lorentz invariance and the new feature of nonzero dispersion together imply that a given physical field be represented by an infinity of (in general, slightly different) tensor fields, one for each equivalent observer. Some consequences of this idea in quantum field theory are investigated. It results, generally speaking, in high momentum cut offs in some expressions. For free fields we remark that the invariant functions turn out continuous and bounded; a « skin effect» violation of microcausality is present in the exterior of the light cone. For interacting fields we mention only that the iteration solutionS-matrix is unambiguous (no subtraction formalism) and has only finite matrix elements. The renormalization idea that self energy parts, etc., only renormalize bare particle parameters must, strictly speaking, be given up. Correction to « point particle» scattering arise in the form of form factor functions of momentum transfersq. These arenot functions ofq2 only, as in currentad hoc theories. The « standard deviation» λ is estimated as nucleon Compton wave length or smaller.
Minimum principles in motor control

Abstract Minimum (or minimal) principles are mathematical laws that were first used in physics: Hamilton's principle and Fermat's principle of least time are two famous example. In the past decade, a number of motor control theories have been proposed that are formally of the same kind as the minimum principles of physics, and some of these have been quite successful at predicting motor performance in a variety of tasks. The present paper provides a comprehensive review of this work. Particular attention is given to the relation between minimum theories in motor control and those used in other disciplines. Other issues around which the review is organized include: (1) the relation between minimum principles and structural models of motor planning and motor control, (2) the empirically-driven development of minimum principles and the danger of circular theorizing, and (3) the design of critical tests for minimum theories. Some perspectives for future research are discussed in the concluding section of the paper.
The relationship of Ureaplasma urealyticum cervical colonization and preterm delivery in high-risk pregnancies

Objective: To determine whether cervical colonization with Ureaplasma urealyticum is associated with preterm delivery in a high-risk clinic population. Methods: Patients from the high-risk clinic at Saint Peter’s University Hospital from December 1997 to June 1999 with history of preterm delivery (PTD), preterm labor, second- trimester loss, or fetal demise served as the study population. Cervical cultures for Ureaplasma (UR) were obtained at the first prenatal visit, and patients were divided into groups based on results. Patients with positive UR served as the study group and were compared with noncolonized patients. All patients with positive cultures were treated. Age, gravidity, parity, number of prenatal visits, gestational age (GA) at first visit, weight gain, drug use, smoking, antibiotic therapy, use of aspirin, use of aspirin and heparin, cerclage, and GA at delivery were the variables collected. The outcome variable was PTD, which was defined as delivery between 24 and 37 weeks of gestation. Significance was set as P less than 0.05. Results: A total of 100 patients met the inclusion criteria. Positive cultures were found in 69% (69/100) of the patients. UR cervical colonization was not significantly associated with PTD. There were no significant differences between groups for the maternal variables studied. Conclusion: In this high-risk clinic population, antibiotic therapy for UR cervical colonization at the first prenatal care visit did not reduce the risk for preterm delivery.
Teaching Social Skills to Shy Single Men

This intervention study compared the efficacy of two treatments for increasing dating frequency and reducing interpersonal discomfort in heterosocial interactions among shy men. Sixty self-described shy single men were randomly assigned to one of three groups: cognitive-behavioral workshop, practice dating, or waiting-list (delayed work-shop) control. All participants agreed to attend a singles function where female observers, posing as party goers, made notes regarding the men's social behavior at this public event. These notes indicated that, overall, workshop participants demonstrated greater levels of social competence than did either practice daters or control group members. Workshop participants also showed greater increases in social self-efficacy than did men in the control group. Dating frequency increased modestly for workshop and practice-dating participants and significantly for delayed workshop participants at a 2-month follow- up.
A Suggested Behavioral Approach to Cost-Benefit Analysis

Whenever problems arise from differences of opinion, there probably exists a lack of understanding of the behavioral situations that contributed to the problems. In his interaction with others, man passes from a level of ignorance to one of awareness and seldom reaches a level of understanding. Without that understanding, however, there is no common premise for resolving problems either with regard to methods or results. Today's executive faces issues that deal not only with the familiar technical business decisions but, more significantly, with related labor, social and environmental responsibilities, and political implications both at home and abroad. Consequently, he must be equipped with the essential tools for analysis of complex behavioral interactions as a requisite to effective application of quantitative techniques. The objective here is to develop a systems approach to behavior by building a common analytical premise. This is done 1 by showing consistency between internal need and environmental resources as determinants of behavior, 2 by establishing values as explanations of these initiating forces, and 3 by then letting these values serve as standards of conduct for man's individual and group personality patterns as end-products of behavior. The basic hypothesis is that a triadic paradigm of unique combinations of need-resource qualities generates corresponding actions and interactions among individuals which are observable in the personalities defined by psychoanalysts. The relationship permits a theoretical classification of behavior patterns for identification, prediction, and resolution of problems within the specific contexts of need and environment that govern man's actions. Through this approach, the manager gains a systematic tool for behavioral analysis on an integrated basis, somewhat like the economic concept of pure competition serving as a reference parameter against which reality becomes a measurable entity. Many salient features had to be condensed in this paper, permitting only a symbolic application of the behavioral theory to cost-benefit analysis of the war in Vietnam. However, present working papers using nonmetric multi-dimensional scaling, factor analyses, and clustering techniques already indicate the applicability of such a behavioral framework.
Computer Use in the Scientific Office

The current research was designed to contribute to the study of scientists' computer use through the development of a linear predictive model of use. Nine variables were selected for study: computer experience, job requirements (profession, time spent on, and importance of 11 work activities), support system size, computer literacy, satisfaction with current tools, overall impact, the importance of computer literacy and skills to management, the importance of computer literacy and skills to colleagues, and interest in computers. There were three components to data collection: (a) on-line recording of participant computer use, (b) a questionnaire, and (c) a discussion period held immediately following completion of the questionnaire. Questionnaire measures were assessed for test-retest reliability and were developed to ensure content validity. Computer use was measured both with a computer-based measurement tool and with the study questionnaire. A cluster analysis on work activity data revealed three disti...
Isolation of Transcriptionally Active Mutants of T7 RNA Polymerase that do not Support Phage Growth

Mutants of bacteriophage T7 RNA polymerase defective in functions other than transcription were sought by random chemical mutagenesis of the cloned gene and selection for inability to support the growth of a T7 mutant whose growth is dependent on T7 RNA polymerase supplied by the host cell. About half of the mutant clones appeared unable to make full-length T7 RNA polymerase, many of them producing a truncated protein. Among 116 mutants expressing full-length protein, two-thirds were severely impaired in transcription, but a surprisingly high one-third were able to direct significant transcription in vivo. Both types of mutation were distributed across much of the gene, as determined by a rapid genetic mapping procedure that allows the lethal mutation in each clone to be localized. One mutation (isolated twice) allowed normal gene expression but prevented the formation of mature ends of T7 DNA from concatemers, which normally happens during packaging into phage particles. Thirty-seven of the mutations appeared to increase the sensitivity of the polymerase to inhibition by T7 lysozyme; all were suppressed by mutations in the lysozyme gene, including one suppressor constructed to retain full amidase activity but to be unable to bind T7 RNA polymerase. The two lysozyme-hypersensitive polymerase mutants analyzed in detail showed premature cessation of transcription during infection. Early proteins and those late proteins specified by genes as far right in T7 DNA as genes 8-9 appeared to be produced normally, but expression of genes farther to the right was strongly depressed. DNA replication was depressed about 50% in one of these mutants and 90% in the other, even though the T7 replication proteins were made in normal amounts at the normal time.
Why the Doctor Will NOT See You Now: The Ethics of Enforcing Covenants Not to Compete in Physician Employment Contracts

When a physician employment relationship terminates, the physician–patient relationship may also be terminated by enforcement of a covenant not to compete, which typically forces the physician to leave the geographic area for a period of time. This gives rise to several ethical dilemmas. The public interest is compromised when enforcement of these covenants contributes to the shortage of physicians in the community, and individual patients are harmed when their physicians are no longer available. The authors undertook a unique study to explore physician perspectives concerning the ethics of banning a physician from practice and the impact of the ban on both the physician and the physician’s patients. The results identified harmful effects that have not been raised in prior scholarly articles or reported court opinions. After reviewing the legal background of covenants not to compete, this paper presents the results of that study and concludes that resorting to the legal system for enforcement of covenants not to compete is not always the ethical course of action.
Torsion of testicular appendage

A 12-year-old boy was evaluated for acute onset of pain in the right scrotum. There was no history of fever or dysuria. On examination, point tenderness was found superior to the right testicle with a bluish skin discoloration. Both testes were normal to palpation. On US, a hypoechoic mass was seen adjacent to the right epididymal head. While the mass had no internal vascularity, there was adjacent hyperemia typical of torsion of a testicular appendage (Figs. 1 and 2). Testicular appendages are remnants of the embryonic mesonephric and paramesonephric ducts. Torsion of testic-