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A computational aeroacoustic (CAA) solver was developed on Graphics Processing Units (GPUs) to solve linearized Euler equations (LEE) for sound propagation. The spatial derivatives are approximated by a 4 order optimized prefactored compact scheme and the increment in time uses a low dissipative and low dispersive Runge-Kutta method. In the current study, the implementation of the prefactored compact scheme, which is normally the “hotspot” of CAA solver, is in a bidiagonal matrix form. Four methods are employed to investigate the solution of a bidiagonal matrix on GPUs. The first method is a coarse-grained parallel approach and assigns one GPU thread to solve a recursive system. The second method employs a parallel cyclic reduction (PCR) approach and assigns one GPU thread to solve a row in the matrix. The third method is a matrix multiplication method. Both the second and the third methods are fine-grained parallel. The last method is a hybrid approach which combines the first method with either the second or the third method. The PCR approach is more suited to two-dimensional (2D) problems whereas the matrix multiplication method achieves a higher speedup for three-dimensional (3D) problems. For a 2D Gaussian pulse scattering problem, the code runs 77 times faster on a Tesla M2050 GPU than on a single Intel Xeon core (2.4GHz). For a spinning mode propagation in a 3D engine bypass duct case, the code runs 40 times faster on two GPUs than on two CPU processes.

Molecular dynamics computer simulations have been performed on Mouse (Mo) and Syrian Hamster (SHa) prion proteins. These proteins differ, primarily, in that the SHa form incorporates additional residues at the C-terminus and also includes a segment of the unstructured N-terminal region that is required for infectivity, The 1-ns simulations have been analyzed by using a combination of dynamical cross-correlation maps, residue-residue contact plots, digital filtering, and residue-based root-mean-square deviations. The results show that the extra residues present in the SHa form at the C- and N-termini produce changes in the stability of key regions of the protein. The loop region between strand S2 and helix B that contains part of the proposed discontinuous binding site for the chaperone, protein X, is found to be more stable in SHa than in the Mo protein; these results are consistent with the NMR data of James et al, (James et al, Proc Natl Acad Sci USA 1997;94:10086-10091), In addition, a degree of flexibility within the region between and including strand S1 and helix A is also shown in SHa, which is not present in the Mo form; the cross-correlation maps suggest that this is a consequence of the additional unstructured N-terminal region. Furthermore, the extra residues in the N-terminal region of SHa are found to form a beta-bridge with the beta-sheet, within which critical point mutations associated with prion diseases lie. The implications of these results for the conformational interconversion pathway of the prion protein are discussed.

The structure and energetics of zinc chlorides (ZnCln2-n, n = 0−4) in aqueous solution are studied by ab initio molecular orbital methods. The first solvation shell is included explicitly, the remainder of the solvent being modeled by the polarizable continuum method. The species Zn(H2O)62+, ZnCl2(H2O)2, ZnCl3(H2O)-, and ZnCl42- are predicted to occur in an aqueous environment. The predictions are consistent with the limited structural and energetic data available. A comparison with the predictions of the continuum model alone shows the necessity of including the first solvation shell explicitly to model solvation energies, although the continuum model is successful in predicting structural changes of ZnCl+ and ZnCl2 upon hydration.

It is suggested that Breit and Tuve's 1925 application of pulses to ionospheric sounding, which led to the most widely used form of radar, also gave rise to a scientific instrument whose utility, flexibility, and general suitability for intended applications place it on a par with such familiar and standard devices as the telescope or spectrograph. By way of background, there is included a discussion of the circumstances attendant upon the first measurement of ionospheric layer height, which took place in 1912.

Experimental and theoretical estimates or the tautomeric equilibria in aqueous 3-hydroxypyrazole are discussed. The use or pK a data is shown to be critically dependent upon the inclusion or corrections reflecting the substitution pattern or the compounds employed. Ab initio calculations, including a high level or electron correlation, or the gas-phase species are combined with both molecular dynamics simulations and continuum methods, to model solvation effects

Experimental and theoretical estimates or the tautomeric equilibria in aqueous 3-hydroxypyrazole are discussed. The use or pK a data is shown to be critically dependent upon the inclusion or corrections reflecting the substitution pattern or the compounds employed. Ab initio calculations, including a high level or electron correlation, or the gas-phase species are combined with both molecular dynamics simulations and continuum methods, to model solvation effects

A method for the rapid detection of Coxiella burnetii and differentiation between strains that cause endocarditis and those that cause acute Q fever is based on the observation that the different strains contain unique plasmid sequences. This method employs the polymerase chain reaction (PCR) and requires knowledge of specific DNA sequences in the region (target) of DNA to be amplified. To detect and differentiate between C. burnetii isolates, two sets of primers are required. The first set was derived from a fragment of plasmid QpH1 which has been detected in all C. burnetii isolates. A second PCR reaction was conducted using primers specific for DNA sequences that are shared only by QpRS plasmid-containing strains of C. burnetii. The first reaction detects the presence of C. burnetii. The second PCR is necessary to determine whether the isolate contains DNA sequences associated with strains causing chronic disease. These procedures detect as few as one to ten organisms.

Evidence is mounting in support of the idea that different isolates of Coxiella burnetii, the etiologic agent of Q fever, are responsible for the distinct disease syndromes observed clinically. Recent studies have shown distinct antibiotic susceptibilities of different isolates of C. burnetii implicated in distinct clinical Q fever syndromes. With this in mind, we performed antibiotic susceptibility testing of the "S" isolate, a chronic-type isolate retrieved from a human patient with chronic disease. Antibiotics with differing efficacies upon the Nine Mile and Priscilla isolates were tested for their abilities to control acute and persistent "S" isolate infection of L-929 cells in vitro. The efficacies of doxycycline, rifampin, and three fluoroquinolone drugs--ciprofloxacin, ofloxacin, and norfloxacin--were tested. Compared to the chronic Q fever-implicated Priscilla isolate, which has been shown to exhibit a significant resistance to these antibiotics, the "S" isolate was much more susceptible. In persistently infected cells (greater than 300 d), the "S" isolate proved to be significantly more resistant to doxycycline, slightly more resistant to ciprofloxacin, slightly more susceptible to rifampin, and equally sensitive to ofloxacin and norfloxacin compared to the acute Q fever-implicated Nine Mile isolate. As with both the Nine Mile and Priscilla isolates, the "S" isolate was more susceptible to doxycycline, rifampin, and ofloxacin in recently infected cells (22 d) compared to cells having been persistently infected. With respect to the resistant nature of the chronic Q fever-implicated Priscilla isolate, as well as the lack of success in treating the "S" isolate in vivo, these results were unexpected. Such data supports an evolving hypothesis that the distinct C. burnetii isolates which may be responsible for the clearly different Q fever syndromes exhibit a spectrum of antibiotic susceptibility ranging from very susceptible (acute-implicate), Nine Mile isolate), to moderately susceptible (chronic-implicated "S" isolate), to moderately resistant (chronic-implicated Priscilla isolate).

The free energy difference for the tautomeric equilibrium of 2-hydroxypyridine/2-pyridone is predicted to be up to 5.3 kJ mol −1 , by the use of the CCSD, QCISD, and QCISD(T) methods, values close to the experimental estimates of 2–3 kJ mol −1 .

Bacterial cell attachment to the surfaces of self-assembled monolayers formed by the adsorption of omega-substituted alkanethiols on transparent gold films has been studied under defined bacterial culture and flow conditions. Phase contrast microscopy was used to quantify the attachment of two organisms, one of medical (Staphylococcus epidermidis) and one of marine (Deleya marina) importance. Self-assembled monolayers terminated with hexa(ethylene glycol), methyl, carboxylic acid and fluorocarbon groups were investigated. Over the range of experimental conditions, self-assembled monolayers formed from HS(CH2)11(OCH2CH2)6OH were found to be uniformly resistant to bacterial attachment, with a 99.7% reduction of attachment for both organisms when compared to the most fouled surface for each organism. On other surfaces, S. epidermidis and D. marina were shown to exhibit very different attachment responses to the wettability of the substratum. While the attachment of S. epidermidis correlated positively with surface hydrophilicity, D. marina showed a preference for hydrophobic surfaces. This study suggests that surfaces incorporating high densities of oligo(ethylene glycol) are good candidates for surfaces that interact minimally with bacteria.

Isolation of Coxiella Burnetii in the standard laboratory setting is hazardous; therefore most diagnoses are based on retrospective detection of a rising antibody titer to C. burnetti. As a result, this disease is usually undiagnosed or misdiagnosed. Methods for the rapid detection of C. burnetti have now been developed that utilize specific hybridization of labeled DNA probes to nucleic acid in clinical samples. One method detects the presence of C. burnetii 16S ribosomal RNA (rRNA); another uses plasmid sequences. We have developed a probe that detects C. burnetii and one that differentiates between Coxiella strains capable of causing chronic disease and those that cause the acute form. Using these probes, C. burnetii can be identified in blood, urine, and tissue samples. The plasmid-derived probes detect as few as 10(4) organisms and less than 1 ng of Coxiella DNA. A third method differentiates between chronic (endocarditis-causing) strains and those that cause acute Q fever. This method uses the polymerase chain reaction (PCR), in which the target regions of DNA are amplified by iterative cycles of Taq I DNA polymerase chain extension to produce up to a 10(6) amplification of the target sequences. When Southern blotting is used in conjunction with PCR, the test detects as few as 2-9 C. burnetti cells.

Calculations of the free energy differences between the tautomer pairs, 2-hydroxypyridine/2-pyridone, and pyridine-2-thiol/pyridine-2-thione, are reported using large (TZV2P) basis sets and electron correlation at the QCISD(T) level. For the hydroxy/oxo system the predicted energy difference (2.9 kJ mol–1) is the same as the experimental value (2.9 ± 0.5 kJ mol–1). For the thiol/thione system, the predicted energy difference (15.2 kJ mol–1) is somewhat larger than the experimental value (9.9 ± 0.5 kJ mol–1). The importance of correlation energy contributions beyond second order is highlighted.

Ab initio molecular orbital methods have been used to predict the relative energies of the three tautomers of 3-amino-1,2,4-triazole, in the gas phase and in aqueous solution. At the highest level of theory employed [6-31G**(CCSD)//6-31G**(HF)] the 1H and 2H tautomers are essentially isoenergetic in the gas phase, with the 4H tautomer 7 kcal mol–1 to higher energy. Both the self-consistent reaction field and polarisable continuum models predict differential stabilisation of the 4H tautomer upon hydration. However, neither model is in accord with the relative energies of the hydrated tautomers suggested by 15N NMR spectroscopic data.

The equilibrium between 6-chloro-2-hydroxypyridine and 6-chloro-2-pyridone has been studied theoretically in the gas phase, in water and in carbon tetrachloride using a combination of electronic structure calculations, including geometry optimization and electron correlation, and molecular dynamics simulations. The use of a 6–31G** basis with correlation, correctly predicts the increased stability of the enol form upon chlorine substitution at the 6 position and, at the MP4 level, yields agreement with the gas phase energetics to within 1.5 kcal mol–1. The accuracy of the computer simulations in predicting the differential free energy of solvation of the two tautomers in water is also ca. 1.5 kcal mol–1, whilst for solvation in carbon tetrachloride the corresponding accuracy is ca. 0.2 kcal mol–1.

It is suggested that Breit and Tuve's 1925 application of pulses to ionospheric sounding, which led to the most widely used form of radar, also gave rise to a scientific instrument whose utility, flexibility, and general suitability for intended applications place it on a par with such familiar and standard devices as the telescope or spectrograph. By way of background, there is included a discussion of the circumstances attendant upon the first measurement of ionospheric layer height, which took place in 1912.

The interactions among Escherichia coli elongation factor G (EF-G), guanine nucleotides, ribosomes, and fusidic acid were investigated by a number of physical techniques. Equilibrium dialysis studies demonstrated the existence of a binary EF-G-GDP complex. This complex forms with a stoichiometry of ca 1:1 and an apparent Ka of 2.5 X 10(5) M-1. While no evidence was obtained for the formation of a ribosome-GDP complex, in the presence of ribosomes, the apparent Ka for guanosine diphosphate (GDP) increased 40-fold over that for binding to EF-G alone. Although the apparent Ka increased, the stoichiometry remained ca. 1 mol of GDP/mol of EF-G. An upper limit of 1.3 X 10(7) M-1 was calculated for the Ka for binding of ribosomes to the EF-G-GDP complex. Fusidic acid had no effect on the apparent Ka's for either the EF-G-GDP or EF-G-beta, gamma-methyleneguanosine triphosphate (GMP-P(CH2)P)=ribosome complexes, but markedly increased the Ka for GDP in the EF-G-GDP-ribosome complex without altering the stoichiometry. The apparent Ka for GDP was shown to be dependent upon the fusidic acid concentration. In addition, the rate of GDP exchange into the quaternary EF-G-GDP-ribosome-fusidic acid complex was inversely related to the fusidic acid concentration. All of the data obtained in these studies suggest that the formation and dissociation of complexes involving EF-G and guanine nucleotides is ordered. GDP is the first component to bind to EF-G, followed by the ribosome, and, finally, fusidic acid. This conclusion is consistent with the kinetic mechanism for the hydrolysis of GTP by EF-G and the ribosome proposed in the preceding paper of this issue (Rohrbach and Bodley (1976b). In addition to these binding studies, guanine nucleotides have also been shown to protect EF-G against both limited trypsinolysis and chemical modification by N-ethylmaleimide. These observations offer additional evidence for the existence of a guanine nucleotide binding site on EF-G.

Using a combination of radioimmunoprecipitation and SDS-polyacrylamide gel electrophoresis of the immunoprecipitate we studied the rate of synthesis of the heavy chain of β-lipovitellin in the liver of immature chicks. In male and female chicks the base-line synthesis of βL-lipovitellin 1 was about 30 molecules per minute and per cell. Four days after a single injection of 40 mg estradiol/kg, as many as 48,000 molecules of βL-lipovitellin were synthesized per minute and per diploid liver cell. The increase in the rate of βL-lipovitellin synthesis could be correlated with an increase in membrane bound mRNA coding for βL-lipovitellin.

Chest roentgenograms of 152 patients with type 2/3 disease observed 3 or more years were reviewed using modified ILO/UC nomenclature. After a mean length of observation of 9.3 years, clinical recovery was observed in 71.7% and radiologic recovery in 48.0% of the patients. Age; duration of observation; mediastinal adenopathy; and character (xyz, pgr, stu), size, extent, and profusion of pulmonary densities were similar in the 53 white and 99 black patients, who differed significantly only in sex distribution. White patients achieved clinical recovery (84.9%) more often than black patients (64.7%) (p = .05). Factors influencing clinical recovery were analyzed by means of stepwise logistic linear regression. The initial roentgenographic features were unrelated to outcome; only race and extrathoracic disease proved to have significant predictive value. The probability of clinical recovery is estimated to be .894 in white patients with disease limited to the chest, .697 in white patients with extrathoracic disease, and .760 in black patients without and .454 in black patients with extrathoracic sarcoidosis. Recovery appears to be related not to the severity of the initial pulmonary reaction but to racially associated factors that influence extrathoracic dissemination as well as lung damage.

A lipopolysaccharide (LPS) was isolated by hot phenol–water extraction from phase II Coxiella burnetii. The LPS was isolated from organisms that had a history of 95 serial yolk sac passages and others that were cloned. The chemical composition of the LPS was partially determined and compared with that of LPS previously isolated from phase I organisms. Most of the sugars present in phase I LPS were detected in phase II LPS; however, there were some quantitative and qualitative differences. The fatty acid profiles of phase I and II LPS were identical. The amount of LPS extracted from phase II organisms was about [Formula: see text] the amount extracted from phase I C. burnetii. Limulus lysate gelation was observed with subnanogram amounts of both phase I and II LPS. In complement fixation tests, both LPSs reacted only with antisera containing antibodies versus phase I antigen. Ouchterlony immunodiffusion tests demonstrated immunological identity of the two LPSs.

A means for adding, without circuit modification or wiring changes, continuously tunable band‐pass or band‐reject selectivity to existing audio amplifiers is described. This takes the form of an external electronic circuit connected to the amplifier by means of a wire attached to the plate pin of one tube, and a common ac ground connection.The arrangement is useful in laboratory and experimental work for temporarily rejecting or amplifying a particular frequency.

Continuous recordings of the instantaneous frequency of the strongest received signal component of WWV-20 (4000 km distant) were made for a period of 30 days in the spring of 1960 at Palo Alto, California. On normal days regular morning and evening frequency shifts, amounting to roughly 1 part in 107, were observed. The received frequency was higher than normal in the morning and lower than normal at night. On magnetically disturbed days, the maximum observed frequency shifts probably amounted to 3 parts in 107, a figure frequently cited by others [Essen, 1935; Booth and Gregory, 1948; Jackson, 1952; Lincoln, 1960]. On days when only the one-hop mode could propagate over the path, the observed frequency shifts were considerably smaller than when the two-hop mode was present. This circumstance may be of practical interest. On many days short-enduring upward frequency shifts amounting to as much as 3 cps, 1.5 parts in 107, were observed. The upward portion of these shifts typically took place in 1 to several minutes; they were followed by small downward shifts lasting several times as long. It is tentatively suggested that these shifts are caused by entry into the ionosphere of the downward-moving clouds of ionization first identified on ionograms by Wells, Watts, and George [1946] and subsequently studied by Bibl [1952]. During magnetically disturbed days, occasional periods were found during which changes in the instantaneous frequency of WWV-20 seemed to correlate reasonably well with changes in the earth's total magnetic field as measured at Palo Alto.

A purified lipopolysaccharide (LPS) isolated from the rickettsial agent of Q fever, Coxiella burnetii phase 1, possesses some of the in vivo and in vitro biological properties previously only associated with bacterial endotoxins. The Coxiella LPS is mitogenic for guinea pig leukocytes, induces non-specific resistance in mice to virulent Candida albicans, causes dermal Schwartzman reactions, and is positive by the limulus lysate assay.

E. coli 70S ribosomes uniformly labeled in vivo with 32PO4 were subjected to varying doses of u.v. radiation and then to the combined action of the RNases A and T1. Following these treatments the ribosomal proteins were separated by trichloroacetic acid precipitation from the noncovalently attached RNA degradation fragments. Subsequent two-dimensional gel electrophoresis and autoradiography of these proteins revealed that significant 32PO4 was associated with unique ribosomal proteins, L2 was among these.

Summary: L929 mouse fibroblast cells and J774 macrophage-like cells are both susceptible to persistent infection with the Q fever agent Coxiella burnetii. Previously this laboratory has shown that persistently infected cell populations multiply with unaltered generation times or cell cycle progression. It has also been reported by others and us that highly infected cells typically exhibit one large parasite-containing vacuole. We now report that lightly and heavily infected cells are capable of division and in the process segregate the parasite-containing vacuole into one of the emerging daughter cells; the companion daughter cell emerges parasite-free. This asymmetric division of infected cells, revealed via photomicrography of stained cells, accounts for the appearance of uninfected cells within persistently infected host cell populations that were previously 100% infected. Some of the persistently infected L929 populations were maintained in culture for over two years without the addition of normal cells.

A case is reported of a successful transplant of kidneys from a 15-month-old girl who died of complications of Reye’s syndrome. The patient is well 28 months after the transplant and? despite treatment for 2 rejection episodes, there has been no increase in viral serologic titers nor evidence of the clinical viral syndrome. The literature on renal transplantation in Reye’s syndrome as well as Reye’s syndrome itself is reviewed. The ’world literature on this subject is sparse and this case is presented to give support and justification for the use of Reye’s syndrome cadaver donors.

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The prevalence of digital technologies is forcing organizations to re-imagine the way their business models are configured, the way their business processes are designed, and the way they work in what is known today as a digital economy. While this brings a plethora of challenges due to the disruptive nature of digital technologies, the digital economy is also bringing plenty of promising opportunities for those who are aware and prepared to embrace the digital evolution. As such, it is imperative for digital enterprises to be opportunity-driven, as soon as they have identified a business problem that can be tackled. They can do so by leveraging the five emerging digitalization trends we are witnessing today, namely: (1) hyper connectivity, (2) supercomputing, (3) cloud computing, (4) smarter world, and (5) cyber security. In this chapter, we describe each trend, what it entails, and what its implications are for enterprises steering towards digitization by leveraging the five digitalization trends. We show how enterprises that benefit from these trends are able to attain not only competitive advantage through innovation, but also adapt to the changing circumstances while capturing new opportunities by means of transforming the way they run their business in the digital economy.

Digital transformation can create new business models, improve business processes, and change how a company works with real-time information. High expectations are set for the resulting disruptive and ongoing innovations, yet promising business transformations, with expected high business benefits for customers and the organizations, often fail because they collide with the company culture. In this chapter two best-practice examples illustrate how to avoid such failure by driving the changes in culture that can lead companies to digital success (The title of this chapter is inspired by Peter Drucker’s alleged statement ‘Culture eats strategy for breakfast’).