cssi/SciSciGPT-SciSciNet huggingface dataset:
Receding horizon optimal control for some stochastic hybrid systems

We consider optimal control problems for a class of hybrid systems with switches dependent on an external event process. In the case where all event times in this process are fully known, the solution to such problems was obtained in prior work. When event times are uncertain or unknown, we have proposed a receding horizon (RH) control scheme in which only some future event information is available within a time window of length T and have obtained several properties of this scheme. In this paper, we provide a full set of properties for this scheme, including the fact that the error due to lack of future event information is monotonically decreasing under certain conditions and may be zero for segments of the sample path, depending on the window length T. This enables the use of a controller based on limited knowledge of future events with limited loss of optimality properties. We further explore the case where T = 0, i.e., allowing no lookahead capability in the controller, as well as the cases of estimating some future event times.
Einsatzmöglichkeiten und Wirtschaftlichkeit von On‐line‐Systemen in der Industrie

Feasibility and economic aspects of on-line systems in industry. Starting with a summary description of the principal practical aims, data are given on the magnitude of the resulting material to be dealt with and thus on the extent of the operation. After a comparison with the most important traditional aids, the advantages to be gained from new technology are shown, such as reduction of time losses, more favourable operational running costs, as well as more extensive possible combinations and more precise selection. The main requirements appear to be a knowledge of numerous sources of information and frequent, if possible daily, updating of data as well as thorough professional understanding. Because of the preponderance of literature references and smaller amount of direct data (factual data or hard facts) the main task in decision making and in supporting established decisions lies in relieving the qualified key staff of tedious and laborious literature searches.
CEO/CFO Certification and Emerging Needs to Separate Facts and Forecasts: Exploring 'Intertemporal Financial Statements' with Two Time-Phases

The Sarbanes-Oxley Act of 2002 created mandatory certification of financial reports by chief executive officers and chief financial officers, possibly exposing them to forecast risks. This is because accounting standards have moved to include more and more forecasts, while the public expects financial statement figures to be much more solid than they actually are. Presenting forecasts separately from facts seems most important now and also to qualify them for the SEC's Safe Harbor protection. "Intertemporal financial statements" are explored here. Their amounts are presented in three columns, "facts," "forecasts," and "total," where the total column is exactly the same as those in conventional statements. All completed transactions and all cash transactions appear in the fact column and all non-cash transactions awaiting terminating transactions appear in the forecast column. Each column is like pre-consolidation statements for a subsidiary and balances on its own in all statements. Investors and regulators will welcome this added breakdown of conventional numbers since hard and soft numbers are clearly separated for a better assessment of corporate financial positions and performances. We also present a principal-agent setting in which it is optimal to remove contractual pressure from forecasts when the environment is unknown or subject to rapid change.
Agile development of workflow applications with interpreted task models

We demonstrate that the development of interactive workflow applications can be made easier by providing developers with custom user interface components that interpret a workflow task model. This enables occasional developers to create workflow applications by adapting template data objects, template user interface pages, and a template workflow task definition. The resulting interactive workflow system is open to agile adaptation by experienced developers. This is an improvement over existing workflow systems which use workflow task models to create workflow application user interfaces that are difficult to extend.
Airway microbial culture and susceptibility patterns in dogs and cats with respiratory disease of varying severity.

Objective – To compare airway microbiological culture and susceptibility results in 2 groups of dogs and cats: 1 with respiratory failure requiring positive pressure ventilation (PPV) and 1 with respiratory disease. Design – Retrospective study. Setting – University teaching hospital. Animals – Fifty-two dogs and cats requiring PPV that had an airway microbiologic culture submitted from October 1, 2003 to October 31, 2008 were included. One hundred and four airway microbiologic cultures from dogs and cats with respiratory disease not requiring PPV were randomly sampled for comparison. Interventions – None. Measurements and Main Results – Patients with respiratory failure were more likely to have a gram-negative enteric isolate identified (P<0.001), while patients with respiratory disease were more likely to have a gram-negative nonenteric isolate (P<0.001) or anaerobic isolate (P<0.001) identified. Aerobic bacterial isolates from patients with respiratory failure were less likely to be susceptible to ampicillin (P=0.006), amoxicillin/clavulonate (P<0.001), chloramphenicol (P=0.004), enrofloxacin (P<0.001), ticarcillin/clavulonate (P=0.004), and the combination of ampicillin with enrofloxacin (P<0.001) than were aerobic bacterial isolates from patients with respiratory disease. Conclusions – Canine and feline patients with respiratory failure severe enough to require PPV exhibit a different pattern of bacterial isolates cultured from their airways when compared with isolates from patients with respiratory disease that has not resulted in ventilator dependence. These isolates are more likely to be resistant to commonly used antimicrobials/antimicrobial combinations than patients in the respiratory disease group. These findings suggest that in canine and feline patients with infectious lower respiratory tract disease, consideration of the severity of the pulmonary insult may allow for better prediction of likely isolates and their antimicrobial susceptibilities. Further prospective studies with a standardized collection technique are warranted.
War of the Words: Reviewing Herbert J. Gans, The War Against the Poor: The Underclass and Antipoverty Policy (1995)

This articles reviews Herbert J. Gans, The War Against the Poor: The Underclass and Antipoverty Policy (1995).
Coherent versus noncoherent massive SIMO systems: Which has better performance?

We consider one single-antenna transmitter communicating over a block-fading channel with a receiver that has a large number of antennas. We analyze coherent schemes with training overhead and noncoherent schemes with no training overhead. The latter systems only know the large scale fading statistics and the additive Gaussian noise power. In contrast to prior work on capacity characterizations of such systems, our approach is based on comparing error exponents with an increasing number of receive antennas. We provide an analytical lower bound on the error exponent for both coherent and noncoherent systems, and describe it explicitly for the case of a communication system with PSK constellations. Based on these analytic expressions, we show that noncoherent schemes can significantly outperform coherent schemes in channels with a strong line of sight component, low SNR or a short coherence time. We present numerical comparisons of our analytical BER performance bounds with Monte Carlo simulations for typical PSK constellations, system sizes and fading/noise statistics.
Apparent motion in geometric depth

The ability to detect small excursions of apparent movement of a point light source was investigated. Apparent movement was achieved by alternately presenting a point source in two different planes. The presentations, each lasting about 500 milliseconds, had an overlap of approximately 8 milliseconds. Using 7 subjects, the limen for apparent motion was a stimulus separation of 43.9 mm, which is a visual angle of 1′ 21″. Possible application of the effect in a highly precise visual guidance system is discussed in light of the results.
Schaffer's Demon

Jonathan Schaffer (2010) has summoned a new sort of demon – which he calls the debasing demon – that apparently threatens all of our purported knowledge. We show that any debasing skeptical argument must attack the justification condition and can do so only if a plausible thesis about justification is false.
Comparison of air and ground transport of cardiac patients.

Purpose: To investigate the outcome of cardiac patients transported by helicopter versus ground ambulance Setting: A hospital-based helicopter program in southeastern Minnesota Methods: Retrospective chart review assessing an 18-month period (January 1998 to June 1999). Charts were reviewed for type of cardiac diagnosis, level of pain, treatments en route, time to intervention, and length of stay (LOS). Two-hundred-sixty-six cardiac patients came by helicopter. Of the 86 turndowns, 50 came by ground ambulance; 28 records were recovered in this group. These patients composed the comparison ground group. Results: Prehospital time was less for patients transported by air than ground transports (P < .001). The amount of time from the call for transport until arrival at our hospital was less for helicopter transports (P = .002). Air transports had more patients with reduced chest pain on arrival. Difference in CCU LOS was not significant (P = .94). Air patients spent an average of 2 fewer days in the hospital than did ground patients (P = .036). Discussion: Helicopter transport benefits the cardiac patient with decreased chest pain as a result of more treatments en route; decreased time from the call until arrival, resulting in decreased time to intervention; and shorter prehospital time and hospital stays. Conclusion: All of these improved variables relate to salvaged cardiac muscle.
Causes of taxonomic sorting by adults: A test of the thematic-to-taxonomic shift

The tendency among adults to sort items into taxonomic and thematic categories was examined in two experiments. Past demonstrations of adults’ preference for taxonomic categories have usually not used stimuli with a salient thematic organization. The stimuli in Experiment 1 could be divided into three equal-size categories either thematically or taxonomically. Under two sets of instructions, the majority of the college-student subjects sorted thematically. In Experiment 2, a subset of the stimuli was changed so that those within it were strongly taxonomically organized. Subjects then preferred to sort the remaining items taxonomically as well. The two experiments explain why many past sorting studies have yielded a taxonomic preference in adults and provide further evidence against a global change from thematic to taxonomic preference with development.
Testing the Difference between Two or More Independent Coefficients Alpha: An Example

Summay.-The method for testing the difference benveen two or more ilzdependent alpha coefficients is provided along with the method for painvise port hoc comparisons. These methods have been available for several years, but apparently have gone unnoticed. An example illustrating the use of the formulas is given. Feldt (1969, 1980) derived tests of the equahty of two values of alpha. Twenty years ago Hakstian and Whalen (1976) provided the method for testing two or more independent alphas and Feldt, Woodruff, and Salih (1987) presented an alternative for that method. Therefore, the methodology for testing two or more alphas has been around for several years, but I have never seen it applied in journal articles. Part of the problem may be that the method is found in technical journals, and statistically unsophisticated researchers may have ~iculty extracting the correct formulas for applied use. The following formulas, from the Feldt, Woodruff, and Salih article, should be used for testing the difference between two or more independent alphas. The formulas have been changed algebraically to make the computations easier, but produce the same results as the original formulas. The sample coefficient alpha, including the Kuder-Fbchardson Formula 20 (KR-2O), is denoted by A to avoid confusion with the symbolic representation of the statistical significance level, usually denoted by alpha (a). The formulas for testing the difference between k independent As with n number of test items and N number of subjects are
Arthroscopic Management of Anterior Capsulolabral Lesions: How and Why

There are a variety of etiologies that may lead to recurrent instability with most of these lesions leading to incompetence of the anterior capsulolabral complex. The anterior labral periosteal sleeve avulsion is a unique pathoanatomical entity that often renders the glenohumeral joint functionally unstable. This lesion, in addition to other anterior capsulolabral injuries, historically, was repaired using open approaches. These techniques are associated with a high level of patient morbidity, and over the past 2 decades have been abandoned for the use of less invasive arthroscopic treatment modalities. Developments in the equipment and techniques used during shoulder arthroscopy have made arthroscopic management of anterior capsulolabral lesions an effective, safe, and reliable mode of treatment. To achieve successful and consistent patient outcomes with arthroscopic repair of anterior labral lesions, an understanding of the surgical indications, surgical setup, arthroscopic techniques, and equipment is necessary.
Effect of Boundaries and Isotopes on the Thermal Conductivity of LiF

In order to test thermal-transport theories with data involving readily calculable phonon scattering rates, the thermal conductivity of LiF has been measured between 1 and 100\ifmmode^\circ\else\textdegree\fi{}K, first for a series of isotopically pure crystals with sandblasted surfaces ranging in mean width from 1 to 7 mm, and then for a series of crystals ranging in isotopic content of $^{7}\mathrm{Li}$ from 99.99 to 51%. These data are used to investigate Casimir's theory, the boundary scattering mechanism, and the importance of normal processes in LiF. Sandblasted crystals at the lowest temperatures are found to exhibit a boundary-limited conductivity proportional to crystal width and the cube of the temperature, in agreement with Casimir's theory. However, the proportionality constant is strongly influenced not only by the sandblasting procedure but also by dislocations in the crystal interior. Further measurements, coupled with annealing studies and etch-pit counts, show that dislocations introduced near the crystal surface during sandblasting play a major role in the frequency-independent surface scattering of phonons assumed in Casimir's theory. The importance of normal processes is assessed by comparing both the boundary and isotope data with conductivities calculated from Callaway's model with normal processes neglected. Berman and Brock have already fitted similar isotope data with Callaway's theory, and normal processes played a crucial part in the fit. The present fits demonstrate the necessity of considering normal processes in LiF by showing that, though boundary data can be matched, even a determined effort to match the isotope data does not succeed when normal processes are neglected. Furthermore, normal processes are shown to provide the only mechanism for improving the fit.
Efficient algorithms for automated process planning of 2.5D machined parts considering fixturing constraints

In this report, algorithms that perform automated set-up sequencing and fixture planning for prototype machining of 2.5D machined parts using three-axis milling and drilling are presented. A framework for the integration of efficient set-up sequencing algorithms with algorithms for fixture planning is developed. At a higher level of abstraction, these algorithms can be applied for automated process planning of 2.5D parts irrespective of the nature of fixturing elements used. The application of these algorithms to situations where standard fixturing elements, such as parallel-sided vices and toe-clamps, are used is also discussed. In addition, an improved version of an existing algorithm for fixture planning using toe-clamps is presented. The algorithms have been implemented as part of a feature-based CAD/CAM environment.
CLASSIFICATION, SYMMETRY AND THE PERIODIC TABLE

Abstract The scientific use of qualitative, descriptive class concepts versus quantitative, casual mathematical relations is first examined, both with respect to their relative importance in the fields of chemistry, physics, and biology, and with respect to the potential relevance of symmetry considerations. The graphical representation of class concepts by means of sorting maps is then introduced and illustrated with examples from the field of chemistry. When atomic number is used as one of the map coordinates, a special class of map is produced that exhibits symmetry features in the form of an approximate periodicity. This, in turn, leads both to enhanced predictive abilities for the maps in questions and to chemistry's most powerful example of the use of class concepts—the periodic table. The paper concludes with a detailed analysis of the current status of the periodic table in chemistry as exemplified by the step—pyramid form of the table and with a brief commentary on the abuse of symmetry considerations in the construction and interpretation of periodic tables in general.
Security through Information Risk Management

Managing information risk means building risk analysis into every business decision. Chief information security officers widely agree that action plans must include risk categorization, communication, and measurement.
Symptom perception and functional morbidity across a 1-year follow-up in pediatric asthma.

The purpose of this study was to examine the association between asthma symptom perception measured during a 5–6 week baseline and functional morbidity measured prospectively across a 1-year follow-up. Symptom perception was measured by comparing subjective ratings with peak expiratory flow rate (PEFR) and forced expiratory volume in one second (FEV1). We hypothesized that accurate symptom perception (ASP) would be associated with less functional morbidity. Participants consisted of 198 children with asthma ages 7–17 recruited from three sites. The children used a programmable electronic spirometer in the home setting to guess their PEFR prior to exhalation. Each “subjective” guess was classified as being in an ASP, dangerous symptom perception (DSP; underestimation of symptoms), or symptom magnification (SM; overestimation) zone based upon the corresponding measurement of PEFR or FEV1. An index of functional morbidity was collected by parent report at baseline and across 1-year follow-up. A greater proportion of ASP blows and a lower proportion of DSP blows based on PEFR predicted less functional morbidity reported at baseline, independent of asthma severity and race/ethnicity. A greater proportion of ASP blows (using PEFR and FEV1) and a lower proportion of SM blows (using FEV1) predicted less functional morbidity across 1-year follow-up. Symptom perception was not associated with emergency department visits for asthma at baseline or across follow-up. In comparison to PEFR, FEV1 more frequently detected a decline in pulmonary function that children did not report. Symptom perception measured in naturalistic settings was associated with functional morbidity at baseline and prospectively across 1-year follow-up. Support was found for including multiple measures of pulmonary function in the assessment of asthma symptom perception. Pediatr Pulmonol. 2007; 42:339–347. © 2007 Wiley-Liss, Inc.
Hydrodynamic explosion of xenon clusters driven by intense XUV light from high harmonic generation

Explosions of xenon clusters exposed to intense XUV pulses are analyzed by time-off-light spectroscopy. Ion charge states and kinetic energy spectra indicate hydrodynamic, not Coulombic, plasma expansion, in contrast to intense infrared/cluster interactions.
Gibbs measure evolution in radial nonlinear wave and Schrödinger equations on the ball

Abstract We establish new results for the radial nonlinear wave and Schrodinger equations on the ball in R 2 and R 3 , for random initial data. More precisely, a well-defined and unique dynamics is obtained on the support of the corresponding Gibbs measure. This complements results from Burq and Tzvetkov (2008) [8] , [9] and Tzvetkov (2006, 2008) [10] , [11] .
CDC-42 regulates PAR protein localization and function to control cellular and embryonic polarity in C. elegans.

Abstract Background: The polarization of the anterior–posterior axis (A-P) of the Caenorhabditis elegans zygote depends on the activity of the par genes and the presence of intact microfilaments. Functional links between the PAR proteins and the cytoskeleton, however, have not been fully explored. It has recently been shown that in mammalian cells, some PAR homologs form a complex with activated Cdc42, a Rho GTPase that is implicated in the control of actin organization and cellular polarity. A role for Cdc42 in the establishment of embryonic polarity in C. elegans has not been described. Results: To investigate the function of Cdc42 in the control of cellular and embryonic polarity in C. elegans , we used RNA-mediated interference (RNAi) to inhibit cdc-42 activity in the early embryo. Here, we demonstrate that RNAi of cdc-42 disrupts manifestations of polarity in the early embryo, that these phenotypes depend on par-2 and par-3 gene function, and that cdc-42 is required for the localization of the PAR proteins. Conclusions: Our genetic analysis of the regulatory relationships between cdc-42 and the par genes demonstrates that Cdc42 organizes embryonic polarity by controlling the localization and activity of the PAR proteins. Combined with the recent biochemical analysis of their mammalian homologs, these results simultaneously identify both a regulator of the PAR proteins, activated Cdc42, and effectors for Cdc42, the PAR complex.
Osteosarcoma of the nasal bone in a child

Osteosarcoma commonly arises in the metaphyses of the long bones and rarely appears in other parts of the long bones or in flat bones. In the head and neck, 6.5% of all osteosarcomas occur in the jaws. A very rare case is presented in which an osteosarcoma developed in the nasal bones of a 4-year 9-month-old girl without any predisposing cause. The literature pertaining to osteosarcomas of the head and neck, particularly in children, also is reviewed.
Beyond ‘bad apples’ and ‘weak leaders’ Toward a neo-institutional explanation of organizational deviance

This article examines two starkly different cases—the abuse of prisoners in the Abu Ghraib prison and the falsification of architectural internship reports—in developing a neo-institutional analysis of deviance within organizations. We argue that the organization’s role extends beyond a failure to act (e.g. monitor, prevent, punish) to include implementing formal structures—decoupling—that make individual deviance both predictable and a predicate of organizational ‘success’. We identify environmental conditions associated with decoupling, strategies to achieve it and organizational responses of deflection. By linking macro-level rule environments, organizational structure and participant behavior, we offer a theoretical framework that elides the long-standing definitional struggles in white-collar crime research through the simultaneous consideration of the organization as environment and the environment of the organization.
A study of atrioventricular conduction in man using premature atrial stimulation and His bundle recordings.

In 20 subjects the effects of controlled premature atrial stimulation on atrioventricular conduction was studied using an electrode catheter technic for recording electrical activity of specialized conducting fibers. The least common type of response observed was that in which A-V conduction delay was limited only to the A-V nodal region (type A). This type of response was obtained whenever the conduction delay in the A-V nodal region increased in direct proportion to the prematurity of a propagated atrial impulse. It was characterized by a progressive prolongation in the P-H interval with ultimate failure of conduction occurring proximal to the His bundle. In type B response, conduction delay occurred in both the A-V nodal and His-Purkinje systems. The recording of a characteristic A-V nodal potential permitted the localization of A-V nodal delay to the N-H interval.
Advanced Automated Solar Filament Detection And Characterization Code: Description, Performance, And Results

We present a code for automated detection, classification, and tracking of solar filaments in full-disk Hα images that can contribute to Living With a Star science investigations and space weather forecasting. The program can reliably identify filaments; determine their chirality and other relevant parameters like filament area, length, and average orientation with respect to the equator. It is also capable of tracking the day-by-day evolution of filaments while they travel across the visible disk. The code was tested by analyzing daily Hα images taken at the Big Bear Solar Observatory from mid-2000 until beginning of 2005. It identified and established the chirality of thousands of filaments without human intervention. We compared the results with a list of filament proprieties manually compiled by Pevtsov, Balasubramaniam and Rogers (2003) over the same period of time. The computer list matches Pevtsov's list with a 72% accuracy. The code results confirm the hemispheric chirality rule stating that dextral filaments predominate in the north and sinistral ones predominate in the south. The main difference between the two lists is that the code finds significantly more filaments without an identifiable chirality. This may be due to a tendency of human operators to be biased, thereby assigning a chirality in less clear cases, while the code is totally unbiased. We also have found evidence that filaments obeying the chirality rule tend to be larger and last longer than the ones that do not follow the hemispherical rule. Filaments adhering to the hemispheric rule also tend to be more tilted toward the equator between latitudes 10∘ and 30∘, than the ones that do not.
Are U4 small nuclear ribonucleoproteins involved in polyadenylation

The mechanism whereby eukaryotic pre-messenger RNAs are polyadenylated is unknown. Most models for polyadenylation invoke cleavage of precursor transcripts at the site of poly(A) addition followed by polymerization of A residues by poly( A) polymerase1–5. Analysis of the sequences surrounding poly(A) addition sites has identified the consensus recognition sequence element AAUAAA as necessary but not sufficient for polyadenylation6–14. A second recognition sequence element CACUG, was observed by Benoit et al.15 to be adjacent to the site of poly(A) addition in several sequenced RNAs. Here, we analyse 61 vertebrate poly(A) addition sequences, define a more extensive recognition sequence for polyadenylation than previously recognized and suggest how the site of poly(A) addition may be chosen. Furthermore, we find that the defined recognition sequence has elements which are complementary to regions within the small nuclear RNA U4, suggesting that U4 small nuclear ribonucleoproteins (snRNPs) may mediate polyadenylation in a fashion similar to the role of U1 snRNPs in splicing. The model invokes hybridization of U4 RNA to AAUAAA recognition elements as related to primary site selection, and hybridization to CAYUG recognition elements as related to cleavage site selection.
Taxonomies to tax the couch-potato's cortex

Growing up in the 1950s, there were only three TV stations , one for each network, so checking the television listings in the newspaper was a relatively simple task. Knowing that I had to get back home in time for The Mickey Mouse Club on weekday afternoons and The Milton Berle Show on Tuesday nights at 8 p.m. was a straightforward matter of scheduling.
Reactivities of Lipid Solvents with Thiobarbituric Acid

SUMMARY Methyl alcohol, ethyl alcohol, chloroform, diethyl ether, petroleum ether, cyclohexane, and carbon tetrachloride were tested for reactivity with thiobarbituric acid. Pigments with absorption maxima at 450 and 532 mμ were readily formed from petroleum ether and diethyl ether; methyl alcohol, ethyl alcohol, chloroform, and hexane reacted, but to a lesser extent; carbon tetrachloride was unreactive. The production of these malonaldehyde-like compounds, presumably from contaminants in the solvents, was increased by heating.
Orthophosphate and phytate extraction from soil components by common soil phosphorus tests

Chemically extractable phosphorus (P) is widely used for environmental risk assessment, because of its strong relationship with P loss through surface runoff and/or subsurface leaching. We used five common soil test extractants, water, 0.01 M CaCl2, Mehlich I, Mehlich III and acidified ammonium oxalate in darkness (AOD) to recover two major P forms, orthophosphate (Pi) and phytate (inositol hexakisphosphate or IHP), which were adsorbed at various P saturation levels on Na-saturated goethite, gibbsite, kaolinite and montmorillonite. Our objective was to evaluate how the P form and mineral type influence the efficiency of these extractants to solubilize P and to examine the inter-correlations between extractable P fractions and the implications in P risk assessment. Phytate had a greater Langmuir adsorption maximum than Pi for all the studied minerals, whereas IHP had a lower extractability than Pi by all extractants. Phosphorus extractabilities increased in the order goethite < gibbsite < kaolinite < montmorillonite. Water and 0.01 M CaCl2 extracted negligible IHP from all P saturation levels of these minerals. Mehlich III and AOD were equivalent in terms of the amount of P extracted. Mehlich III-P showed the best prediction of AOD-P, which is used for estimating soil degree of P saturation (DPS), whereas Mehlich I had a close relationship with AOD-P within a P form. The relationship between DPS estimated by AOD extraction and the true surface P saturation and the factors affecting the relationship were discussed in the model systems.
Multiattribute utility copulas for multiobjective control

In this paper, a design of control laws for mobile agents intending to accomplish multiple objectives is proposed. The agents wish to reach assigned waypoints and at the same time avoid collisions between one another and with static obstacles. A gradient-based controller is constructed using non-negative objective functions and a multiattribute utility copula. Parameters of the multiattribute utility function represent an agent's preference towards the given objectives. Simulations were conducted to demonstrate the control law's ability to accomplish both objectives as well as to illustrate the effects of varying the parameters of the multiattribute utility functions.
Cryptobiosis — a peculiar state of biological organization

Abstract David Keilin (Proc. Roy. Soc. Lond. B, 150, 1959, 149–191) coined the term ‘cryptobiosis’ (hidden life) and defined it as ‘the state of an organism when it shows no visible signs of life and when its metabolic activity becomes hardly measurable, or comes reversibly to a standstill.’ I consider selected aspects of the 300 year history of research on this unusual state of biological organization. Cryptobiosis is peculiar in the sense that organisms capable of achieving it exhibit characteristics that differ dramatically from those of living ones, yet they are not dead either, so one may propose that cryptobiosis is a unique state of biological organization. I focus chiefly on animal anhydrobiosis, achieved by the reversible loss of almost all the organism's water. The adaptive biochemical and biophysical mechanisms allowing this to take place involve the participation of large concentrations of polyhydroxy compounds, chiefly the disaccharides trehalose or sucrose. Stress (heat shock) proteins might also be involved, although the details are poorly understood and seem to be organism-specific. Whether the removal of molecular oxygen (anoxybiosis) results in the reversible cessation of metabolism in adapted organisms is considered, with the result being ‘yes and no’, depending on how one defines metabolism. Basic research on cryptobiosis has resulted in unpredicted applications that are of substantial benefit to the human condition and a few of these are described briefly.
The use of cyclofructans as novel chiral selectors for gas chromatography

Cyclofructans cannot be used as chiral stationary phases for GLC in their native states. This is due to their high melting points and their inability to be solubilized in other liquid stationary phases. However, when cyclofructans are derivatized (via the 3-, 4-, or 6-hydroxyl groups) they can then be dissolved in an achiral matrix and the mixture is suitable as a GLC chiral stationary phase. In this study, per-O-methylated cycloinulohexaose (PM-CF6), per-O-methylated cycloinuloheptose (PM-CF7) and 4,6-di-O-pentyl cycloinulohexaose (DP-CF6) were tested as new chiral selectors for GLC. Enantiomeric separations of several different compounds were observed when using the derivatized cyclofructans as chiral selectors. The enantiomers separated include esters, β-lactams, alcohols, and amino acid derivatives. Differences in the enantiomeric separations obtained by using PM-CF6, PM-CF7 and DP-CF6 as the chiral selector were observed. These differences gave some insight as to the mechanism of enantioselectivity for permethylated cyclofructans as GLC chiral selectors.
Magnetic Properties of Self-Assembled Fe Nanoparticle Arrays

Abstract : The magnetic properties of multilayer arrays of Fe nanoparticles were compared with those of frozen, dilute suspensions of the same particles. The array sample displayed larger coercivity in both hysteretic and remanent magnetization measurements. However, the derivative of the remanent magnetization curve shows a much broader switching field distribution for the arrays than for the dilute sample. Magnetic relaxation measurements show the convergence of the time dependent properties of the samples at large times, and much more rapid relaxation in the arrays at short times.
Atmospheric guidance law for planar skip trajectories

The applicability of an approximate, closed-form, analytical solution to the equations of motion, as a basis for a deterministic guidance law for controlling the in-plane motion during a skip trajectory, is investigated. The derivation of the solution by the method of matched asymptotic expansions is discussed. Specific issues that arise in the application of the solution to skip trajectories are addressed. Based on the solution, an explicit formula for the approximate energy loss due to an atmospheric pass is derived. A guidance strategy is proposed that illustrates the use of the approximate solution. A numerical example shows encouraging performance.
Alzheimer's disease: Initial report of the purification and characterization of a novel cerebrovascular amyloid protein

A purified protein derived from the twisted beta-pleated sheet fibrils in cerebrovascular amyloidosis associated with Alzheimer's disease has been isolated by Sephadex G-100 column chromatography with 5 M guanidine-HC1 in 1 N acetic acid and by high performance liquid chromatography. Amino acid sequence analysis and a computer search reveals this protein to have no homology with any protein sequenced thus far. This protein may be derived from a unique serum precursor which may provide a diagnostic test for Alzheimer's disease and a means to understand its pathogenesis.
An automated microdensitometer for the quantitation of pherograms and zymograms in acrylamide gels

Abstract An automated optical density analyzer for microdensitometric measurements of electrophoretic patterns on acrylamide gels is described. The instrument records the densitometric trace of a pherogram or zymogram, automatically selects and integrates each peak, delineates the peaks on the densitometric trace, and presents the integral for each peak in digital form on paper tape. Bands as small as 35 μ in width can be accurately quantitated over a range of 0.01 to 2.0 optical density units at a maximum rate of almost 4000 counts per second.
Estimation of Covariate Effects With Current Status Data and Differential Mortality

The assessment of the impact that socioeconomic determinants have on the prevalence of certain chronic conditions reported by respondents in population surveys must confront two problems. First, the self-reports could be in error (false positives and false negatives). Second, those reporting are a selected sample of those who ever experience the problem, and this selection is heavily influenced by excess mortality attributable to the condition being reported. In this article, we use a combination of empirical data and microsimulation to (a) assess the magnitude of the bias attributable to the selection problem, and (b) suggest an adjustment procedure that corrects for this bias. We find that the proposed adjustment procedure considerably reduces the bias arising from differential mortality.
Effect of 20,25-diazacholesterol on viability and steroid synthesis capability of cultured chick embryo pectoral muscle cells.

Abstract The anticholesterolemic drug 20,25-diazacholesterol (DAC) inhibits the transfer of radioisotope from acetate to cholesterol in cultured chick embryo pectoral muscle cells. In a 12 hour parallel exposure to tracer and drug (1 μg/ml culture fluid), inhibition was complete as determined by radiogas chromatography (RGC). Drug levels in excess of 5 μg/ml caused cell lysis. RGC/mass spectrometry (selected ion monitoring mode) revealed that desmosterol did not accumulate as a result of the treatment nor was radioactivity transferred to desmosterol. Mass and radioactivity did accumulate in other steroids. The significance of these findings on DAC's mode of action as an anticholesterolemic and myotonia-inducing agent, is discussed.
Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry of polymers

Matrix-assisted laser desorption/ionization mass spectrometry has been demonstrated to be a powerful analytical technique for the analysis of polymeric materials. The advantages of this technique for such analyses include low sample consumption, ease of sample preparation, short analysis times, and soft ionization which leads to negligible or no fragmentation of analytes. It provides absolute, fast and accurate molecular masses for polymers with narrow polydispersity as opposed to relative masses provided by other techniques. It provides masses for the entire polymer distribution instead of the average value, hence providing molecular mass information which can be used to obtain the mass of the end-groups, mass of the repeat unit (monomer), and chemical modifications on the polymer if oligomer resolution is attained. This review concentrates on the developments in methodology that have allowed for the increased use of this technique for polymer analysis.
Time-Dependent Effect of Oral Procainamide in Patients with Exertional Arrhythmias

Abstract The direct translation of procainamide pharmacokinetic data such as absorption and elimination half-lives into practical dosage regimen recommendations involves the assumption that procainamide is reversibly acting, i.e., its antiarrhythmic effect is directly related to its presence in plasma (1). Studies (2–4) have established effective plasma concentration ranges of 4–8 and 4–10 μ g/ml in hospitalized patients with acute myocardial infarction or coronary artery disease.
Asymptomatic urolithiasis in living donor transplant kidneys: initial results.

Objectives During the preoperative evaluation of potential kidney donors, the increased sensitivity of spiral computed tomography (CT) could detect more asymptomatic small (less than 4 mm) renal calculi. However, whether these stones will be of consequence later has yet to be determined. We evaluated the rate of spontaneous passage, development of symptoms, and change in the size of asymptomatic renal calculi in donor kidneys transplanted without removal of the calculi. Methods Five donor kidneys from living donors were transplanted with small (less than 4 mm), asymptomatic renal calculi incidentally detected on CT (eight stones). No donors had any metabolic derangements or history of previous lithiasis. Each kidney was laparoscopically removed and transplanted with the calculi in situ. The recipients were followed up with serial creatinine measurements, history taking, and CT scans. Results None of the recipients had had any symptoms consistent with the progression of disease, including hydronephrosis, renal failure, or the elevation of serum creatinine at a mean follow-up of 711 ± 334 days. The follow-up CT scans showed spontaneous passage of the stones in 3 patients. In the remaining 2 patients, two of the stones remained stable, and one had increased in size from 1 to 2 mm. Those with the stones remaining had had a significantly shorter length of follow-up (204 ± 72 versus 711 ± 200 days, P Conclusions In our series of 5 patients with small asymptomatic renal calculi, none of the patients have had complications, and only three of the eight stones were still in situ at the latest follow-up visit. Transplantation of small (less than 4 mm), asymptomatic stones in situ can be safely performed with adequate follow-up and monitoring for the development of obstructing transplant stones.
Nitric oxide gas phase release in human small airway epithelial cells

Asthma is a chronic airway inflammatory disease characterized by an imbalance in both Th1 and Th2 cytokines. Exhaled nitric oxide (NO) is elevated in asthma, and is a potentially useful non-invasive marker of airway inflammation. However, the origin and underlying mechanisms of intersubject variability of exhaled NO are not yet fully understood. We have previously described NO gas phase release from normal human bronchial epithelial cells (NHBEs, tracheal origin). However, smaller airways are the major site of morbidity in asthma. We hypothesized that IL-13 or cytomix (IL-1β, TNF-α, and IFN-γ) stimulation of differentiated small airway epithelial cells (SAECs, generation 10–12) and A549 cells (model cell line of alveolar type II cells) in culture would enhance NO gas phase release. Confluent monolayers of SAECs and A549 cells were cultured in Transwell plates and SAECs were allowed to differentiate into ciliated and mucus producing cells at an air-liquid interface. The cells were then stimulated with IL-13 (10 ng/mL) or cytomix (10 ng/mL for each cytokine). Gas phase NO release in the headspace air over the cells was measured for 48 hours using a chemiluminescence analyzer. In contrast to our previous result in NHBE, baseline NO release from SAECs and A549 is negligible. However, NO release is significantly increased by cytomix (0.51 ± 0.18 and 0.29 ± 0.20 pl.s-1.cm-2, respectively) reaching a peak at approximately 10 hours. iNOS protein expression increases in a consistent pattern both temporally and in magnitude. In contrast, IL-13 only modestly increases NO release in SAECs reaching a peak (0.06 ± 0.03 pl.s-1.cm-2) more slowly (30 to 48 hours), and does not alter NO release in A549 cells. We conclude that the airway epithelium is a probable source of NO in the exhaled breath, and intersubject variability may be due, in part, to variability in the type (Th1 vs Th2) and location (large vs small airway) of inflammation.
Lid Protractor Force Generation in Graves' Eye Disease

The posterior vector of the lid protractor force was measured in 29 patients with Graves' eye disease (GED) and 70 normal subjects. Patients with GED had significantly lower mean lid protractor force generation than normal subjects, although GED patients with compressive optic neuropathy did not show this difference. There was a negative correlation between the posterior force vectors and the exophthalmometer reading in GED patients only. It is conjectured that these two factors are linked by orbital and lid inflammation. The inflammation that increases orbital bulk, and thus increases the exophthalmometer reading, may well cause atrophy in the orbicularis oculi muscles, decreasing its force generation.
Evaluation of total energy-rate feedback for glidescope tracking in wind shear

Low-altitude wind shear is recognized as an infrequent but significant hazard to all aircraft during take-off and landing. A total energy-rate sensor, which is potentially applicable to this problem, has been developed for measuring specific total energy-rate of an airplane with respect to the air mass. This paper presents control system designs, with and without energy-rate feedback, for the approach to landing of a transport airplane through severe wind shear and gusts to evaluate application of this sensor. A system model is developed which incorporates wind shear dynamics equations with the airplance equations of motion, thus allowing the control systems to be analyzed under various wind shears. The control systems are designed using optimal output feedback and are analyzed using frequency domain control theory techniques. Control system performance is evaluated using a complete nonlinear simulation of the airplane and a severe wind shear and gust data package. The analysis and simulation results indicate very similar stability and performance characteristics for the two designs. An implementation technique for distributing the velocity gains between airspeed and ground speed in the simulation is also presented, and this technique is shown to improve the performance characteristics of both designs.
Siderophore-fluoroquinolone conjugates containing potential reduction-triggered linkers for drug release: synthesis and antibacterial activity

Syntheses of two Siderophore–fluoroquinolone conjugates with a potential reduction triggered linker for drug release are described. The “trimethyl lock” based linker incorporated in the conjugates was designed to be activated by taking advantage of the reductive pathway of bacterial iron metabolism. Electrochemical and LC–MS studies indicated that the linker is thermodynamically reducible by common biological reductants and the expected lactonization proceeds rapidly with concomitant release of the drug. Antibacterial activity assays revealed that conjugates with the reduction-triggered linker were more potent than their counterparts with a stable linker, which suggests that drug release occurs inside bacterial cells.
Association and insertion complexes of nickel with water and methanol studied using Kohn-Sham theory

The complexes formed by simple association of the nickel atom with water and methanol, and those formed by insertion of nickel into O-H and O-C bonds, have been studied by the Linear Combination of Gaussian-type orbitalsdensity functional (LCGTO-DF) method. The binding energies calculated for theassociation complexes are 7 kcal/mol for both Ni(H2O) and Ni(CH3OH). These association complexes have equilibrium geometries characterized by a tetrahedral arrangement of bonds and lone pair around the oxygen atom. Theinsertion complexes HNiOH and HNiOCH3 are more stable than the association complexes by 14 and 18 kcal/mol, respectively. The H3CNiOH insertion complex is still more stable, by an additional 14 kcal/mol. In all five complexes, the lowest singlet and triplet states are nearly degenerate. Comparison of calculated frequencies with infrared spectra of matrix isolated species [MA Park (1988) PhD thesis, Rice University] indicates that only triplet states are seen in the experiment.