cssi/SciSciGPT-SciSciNet huggingface dataset:
Genetic analysis of the switch that controls porin gene expression in Escherichia coli K-12☆

The two-component regulatory system, OmpR and EnvZ, in Escherichia coli controls the differential expression of ompF and ompC in response to medium osmolarity. Previous studies suggest that EnvZ functions as a membrane sensor relaying information to the DNA-binding protein, OmpR, which in turn activates expression of the appropriate promoter. A strategy has been devised to isolate and characterize a collection of missense mutations in ompR that alter, but do not abolish protein function. Mutants were isolated using strains that contain the ompR and envZ genes in separate chromosomal locations yet maintain the production of both regulatory proteins at physiological levels. Such an arrangement facilitates ompR diploid analysis and tests of epistasis with known envZ mutations. The data obtained indicate that OmpR works in both a positive and negative fashion to control the transcription of ompF and this result forms the basis of a model for porin regulation that explains the switch from OmpF to OmpC production in response to increasing medium osmolarity.
Intraoperative US in patients undergoing surgery for liver neoplasms: comparison with MR imaging.

PURPOSE: To retrospectively compare intraoperative ultrasonography (US) and preoperative magnetic resonance (MR) imaging with contrast material enhancement for the depiction of liver lesions in patients undergoing hepatic resection. MATERIALS AND METHODS: A radiologist (D.V.S.) and a surgeon (K.K.T.) retrospectively identified 79 patients (36 female and 43 male patients; age range, 10–78 years; mean age, 57 years) who had undergone surgical resection for primary liver tumor or metastasis and had also undergone preoperative contrast-enhanced MR imaging within 6 weeks before surgery. MR imaging was performed with a 1.5-T system. Dedicated intraoperative US of the liver was performed or supervised by a gastrointestinal radiologist using a 7.5-MHz linear-array transducer, after adequate hepatic mobilization by the surgeon. Histopathologic evaluation of the 159 resected hepatic lesions served as the reference standard. The lesion distribution included colon cancer metastasis (n = 122), hepatocellular carcinoma...
A high-throughput screening fluorescence polarization assay for fatty acid adenylating enzymes in Mycobacterium tuberculosis.

Abstract Mycobacterium tuberculosis, the etiological agent of tuberculosis (TB), encodes for an astonishing 34 fatty acid adenylating enzymes (FadDs), which play key roles in lipid metabolism. FadDs involved in lipid biosynthesis are functionally nonredundant and serve to link fatty acid and polyketide synthesis to produce some of the most architecturally complex natural lipids including the essential mycolic acids as well as the virulence-conferring phthiocerol dimycocerosates, phenolic glycolipids, and mycobactins. Here we describe the systematic development and optimization of a fluorescence polarization assay to identify small molecule inhibitors as potential antitubercular agents. We fluorescently labeled a bisubstrate inhibitor to generate a fluorescent probe/tracer, which bound with a KD of 245 nM to FadD28. Next, we evaluated assay performance by competitive binding experiments with a series of known ligands and assessed the impact of control parameters including incubation time, stability of the signal, temperature, and DMSO concentration. As a final level of validation the LOPAC1280 library was screened in a 384-well plate format and the assay performed with a Z-factor of 0.75, demonstrating its readiness for high-throughput screening.
Some Trends in the World Economy and their Implications for International Business Strategy

* This brief essay addresses 3 questions. First, what are some intermediate trends in the world economy that promise to shape its structure and behavior over the next decade? Second, what are some long-term trends in the world economy that promise to shape its structure and behavior over the next quarter-century or more? Third, what are some implications of these intermediate and long-term trends for international business strategy? Clearly, answers to these questions are speculative. Furthermore, I belong to a crowd that has much to be modest about concerning its ability to anticipate the world economy, as was amply demonstrated by the monetary and energy "shocks" of the 1970s. With that disclaimer in mind, here are my thoughts about some intermediate and long-term futures of the international economy and the implications of those futures for international business.
Crowding depression of UV-mutagenesis in E. coli

Abstract Strains of E. coli B/r were exposed to UV radiation and assayed for reversion mutation, using a standard selection medium. If more irradiated bacteria were assayed per petri dish, a proportional increase in the number of indicated reversion mutants was found only up to a limiting plating density. Beyond a density of about 10 8 viable bacteria per petri dish, the number of indicated revertants per viable bacteria assayed (the mutation frequency) decreased as the plating density was increased. The crowding depression of mutagenesis was more severe for de novo and converted suppressor mutations, the mutation frequency being reduced 100-fold at a plating density of about 6 × 10 9 viable bacteria per plate. The effect on backmutation was 10 times less. Crowding depression of mutagenesis occured in excision-proficient and -deficient strains, with identical effects in the 2 strains on de novo and converted suppressor mutation, but different effects on backmutations. There were no accompanying effects on viability. Irreversible loss of potential mutants during crowded growded growth was indicated in was-off experiments. The kinetics suggested a half-life of approximately 1 h. Kinetics for accumulation by the bacteria of the limiting metabolite (tyrosine) on the assay plate indicated a short period of time for protein synthesis, but direct examination of the proteins synthesized during early growth on a crowded plate demonstrated successful induction of recA protein. The results suggested a possible disruption in the rec/lex respondency system somewhere between induction of recA protein and the various end points, including mutational repair, in cells plated close to one another.
Evidence for an Albian Hudson arm connection between the Cretaceous Western Interior Seaway of North America and the Labrador Sea

Numerous researchers have alluded to the existence of a Cretaceous Hudson Arm connection between the Labrador Sea and the Western Interior Seaway of North America. However, the evidence for this marine connection has been circumstantial. In this paper we present sedimentary geochemical data that indicate a marine influence in the Albian Mattagami Formation of the Moose River basin, James Bay Lowlands, Ontario. The facies associations between dinoflagellate-bearing laminated mudstones, fluvial sandstones, and early pyrite mineralization are interpreted to indicate deposition in the central basin of an estuary. We use the facies association between the estuarine fill and coeval kaolinitic paleosols in the Moose River basin, and in similar deposits in Quebec and Labrador, to reconstruct a southern shoreline of the Albian Hudson Arm to the Cretaceous Western Interior Seaway. We suggest that development of the Hudson Arm connection between the Labrador Sea and the Cretaceous Western Interior Seaway may be related to a regional extensional regime associated with rifting between Labrador and Greenland, and the passage of eastern North America over Cretaceous hotspots.
Modeling of a distributed device for simultaneous reactive vibration suppression and energy harvesting

Distributed devices or treatments are a mainstay of passively suppressing structural vibrations. In some cases, piezoelectric materials were included within the devices to utilize them as actuators. Interest in energy harvesting encourages a reassessment of these devices, using the piezoelectric materials as a means to convert input vibrational energy into electrical power. A numerical model of one such device, exhibiting mass-spring-damper dynamics, attached to a vibrating host structure is described and validated against 3D finite element analysis. The model is utilized to evaluate the simultaneous goals of passive vibration attenuation and energy harvesting of devices on a lightweight, clamped panel. The objectives are found to be partly in opposition, particularly when the total mass of the added devices becomes more substantial. This feature is widely neglected in employing mass-spring systems as energy-harvesting devices, where the mass of the device is insubstantial relative to the main structure. ...
Cavity-loss dependence of erbium glass laser lines

The competition of the 1.536-μm and the 1.543-μm laser lines of erbium in zinc aluminophosphate glass is presented. Experimental results show that the 1.536-μm line oscillates under high-loss conditions whereas the 1.543-μm line oscillates under low-loss conditions. Both Q -switch and long-pulse data are included.
Conformational epitope mapping of Pru du 6, a major allergen from almond nut.

Abstract Tree nuts are a widely consumed food. Although enjoyed safely by most individuals, allergic reactions to tree nuts, including almond, are not uncommon. Almond prunin (Pru du 6), an 11S globulin (legumin), is an abundant nut seed protein and a major allergen. Conformational epitope mapping studies of prunin have been performed with a murine monoclonal antibody (mAb) 4C10. This mAb reacts with non-reduced but not reduced prunin in immunoblotting assays, indicating the recognition of a conformational epitope. 4C10 competes with patient IgE, as assessed by ELISA, indicating clinical significance of the epitope. To characterize the 4C10 epitope, hydrogen/deuterium exchange (HDX) monitored by 14.5 T Fourier transform ion cyclotron resonance mass spectrometry (MS) was performed on the native prunin–4C10 complex and on uncomplexed native prunin. Several epitope candidate peptides that differ in deuterium uptake between the complexed and uncomplexed forms were identified. The epitope was further mapped by analyzing chimeric molecules incorporating segments of the homologous soybean allergen, Gly m 6, in immunoassays. These data indicate that the 4C10 epitope overlaps with a subset of patient IgE binding epitopes on almond prunin and further supports HDX-MS as a valid technique for mapping conformational epitopes.
Bacille Calmette Guérin immunization of health care workers exposed to multidrug-resistant tuberculosis: a decision analysis.

Abstract Setting: North American health care workers with exposure to multidrug-resistant tuberculosis. Objective: To evaluate the relative utilities of bacille Calmette Guerin (BCG) immunization and post-infection chemoprophylaxis for the protection of health care workers exposed to multidrug-resistant Mycobacterium tuberculosis Design: Decision analysis using SMLTREE software and published data for probabilities. Results: BCG vaccination was preferred by a small margin over post-infection chemoprophylaxis. Sensitivity analysis revealed that possible changes in probability values used tended to tilt the result towards use of BCG vaccination. The threshold for protective efficacy of BCG vaccination was 26%. Conclusions: BCG vaccination should be considered for health care workers in environments where there is a substantial risk of exposure to multidrug-resistant tuberculosis.
Polymorphism and inclusion properties of three-dimensional metal-organometallic frameworks derived from a terephthalate sandwich compound.

An organometallic sandwich compound of terephthalic acid, namely, [(η5-Cp)FeII{η6-(1,4-C6H4(COOH)2)}]+ (H21+), is reported, along with X-ray single crystal structures of [H1·H21][PF6] and H1. [H21·H1][PF6] was reacted with the nitrate salts of CoII and NiII to yield a series of three-dimensional (3D) metal-organometallic framework (MOMF) materials of the composition [M3(1)4(μ-H2O)2(H2O)2][NO3]2·xsolvent (M = CoII (2), NiII (3); xsolvent = 4EtOH, or 2DMF·2H2O). These framework structures were shown by single crystal and powder X-ray diffraction to be polymorphic, possessing identical 3D body-centered tetragonal network topologies, but differing in the manner by which the [CpFe]+ groups are arranged within the two-dimensional, square grid sheets of the 3D networks. α-2-EtOH, β-2-EtOH, α-3-EtOH, β-2-DMF, and β-3-DMF were thermally desolvated, giving rise to isolable apohosts of composition [M3(1)4(μ-H2O)2(H2O)2][NO3]2 (M = CoII (2), NiII (3)) that were shown by PXRD to possess different, as yet unknown, crys...
Comparing entering freshmen's perceptions of campus marijuana and alcohol use to reported use.

Use of marijuana and alcohol among current college students (N = 1101) was compared to the perceptions and use of entering freshmen (N = 481) surveyed before the start of classes. Entering freshmen significantly misperceived campus norms for marijuana use, over-estimating that almost every student used in the last 30 days, p < .001. Perceptions of alcohol use were relatively accurate. These discrepancies in perception could account for why 40.5% of entering students perceived the campus atmosphere to be promoting marijuana use, whereas only 16.2% perceived the campus atmosphere to be promoting alcohol use. How these misperceptions of social norms might be influenced by the reputation of the campus—and how this might affect potential applicants and enrolled students' behaviors are discussed.
A comparative study of theoretical methods on Goertler instability

Goertler vortices arise in boundary layers along concave surfaces due to centrifugal effects and these vortices in combination with Tollmien-Schlichting (TS) waves and crossflow vortices may play an important role in triggering early transition. There have been two distinct theoretical approaches to solve the problem. In the classical, normal-mode approach (NMA) the linear development of Goertler vortices is reduced to an eigenvalue problem. In the other method, initiated by Hall, the governing partial differential equations for the perturbations which are parabolic in the streamwise direction, are solved as an initial value problem. This method predicts multiple neutral curves depending on how and where the mean flow is perturbed, unlike the NMA where a unique but different neutral curve is predicted by each investigator. The present paper attempts to compare the two techniques and shows that mutually compatible results can be obtained when physically consistent assumptions are made.
Functional magnetic resonance imaging evidence of augmented pain processing in fibromyalgia

Objective To use functional magnetic resonance imaging (fMRI) to evaluate the pattern of cerebral activation during the application of painful pressure and determine whether this pattern is augmented in patients with fibromyalgia (FM) compared with controls. Methods Pressure was applied to the left thumbnail beds of 16 right-handed patients with FM and 16 right-handed matched controls. Each FM patient underwent fMRI while moderately painful pressure was being applied. The functional activation patterns in FM patients were compared with those in controls, who were tested under 2 conditions: the “stimulus pressure control” condition, during which they received an amount of pressure similar to that delivered to patients, and the “subjective pain control” condition, during which the intensity of stimulation was increased to deliver a subjective level of pain similar to that experienced by patients. Results Stimulation with adequate pressure to cause similar pain in both groups resulted in 19 regions of increased regional cerebral blood flow in healthy controls and 12 significant regions in patients. Increased fMRI signal occurred in 7 regions common to both groups, and decreased signal was observed in 1 common region. In contrast, stimulation of controls with the same amount of pressure that caused pain in patients resulted in only 2 regions of increased signal, neither of which coincided with a region of activation in patients. Statistical comparison of the patient and control groups receiving similar stimulus pressures revealed 13 regions of greater activation in the patient group. In contrast, similar stimulus pressures produced only 1 region of greater activation in the control group. Conclusion The fact that comparable subjectively painful conditions resulted in activation patterns that were similar in patients and controls, whereas similar pressures resulted in no common regions of activation and greater effects in patients, supports the hypothesis that FM is characterized by cortical or subcortical augmentation of pain processing.
On the exact control of mechanical systems

A general procedure for obtaining the exact control forces to be exerted on a mechanical system to maintain constraints is introduced in this paper. It is illustrated through a simple example. The discussion extends to Nature's choice of control forces and its relation to the general control forces.
Optimization of a Surface Plasmon Enhanced Metal-Semiconductor-Metal Photodetector on Gallium Arsenide

The effects of grating geometry on a Surface Plasmon enhanced planar Metal-Semiconductor-Metal photodetector on GaAs are investigated via Finite-difference Time-domain simulations. Substrate absorption is increased by a factor greater than 10 without compromising time response.
Climatic change and the broad-scale distribution of terrestrial ecosystem complexes

The broad-scale distribution of terrestrial ecosystem complexes is determined in large part by climate and can be altered by climatic change due to natural causes or due to human activities such as those leading to increasing atmospheric CO2 concentration. Classifications that recognize the dependence of natural vegetation on climate provide one means of constructing maps to display the impact of climatic change on the geography of major vegetation zones. A world map of the Holdridge Life-Zone Classification, developed from approximately 8,000 meteorological records, is compared with a Holdridge Map with average temperature increments simulated by a. model of climate under elevated atmospheric CO2 concentration. The largest changes are indicated at high latitudes, where the simulated temperature increase is largest and the temperature intervals defining life zones are smallest. Boreal Forest Zones are replaced by either Cool Temperate Forest or Cool Temperate Steppe, depending on average precipitation. Changes in the tropics are smaller; however, in some regions, Subtropical Moist Forest is replaced by Tropical Dry Forest.
N concentration controls decomposition rates of different strains of ectomycorrhizal fungi

Abstract The decomposition of soil organic matter in forest ecosystems is important in two ways. First, soil organic matter is the largest pool of C in terrestrial ecosystems, so understanding global carbon cycling requires an appreciation of the factors that control the size of that pool and the fluxes through it. Among these factors are those that control the rate of organic matter decomposition. Second, organic matter decomposition is the major process controlling the supply of nutrients to plants. In some ecosystems ectomycorrhizal fungi comprise a surprisingly large fraction of soil organic matter. However, little is known of the rates of decomposition of ectomycorrhizal fungi, or of the factors that control those rates. Therefore, we set out to examine the relationship between N concentrations and decomposition rates of ectomycorrhizal fungi using a wide variety of strains isolated from a Pinus resinosa plantation. We found that substantial variation among strains existed in decomposition rate, and that decomposition rate was highly correlated with tissue N concentration. We conclude, therefore, that the structures of ectomycorrhizal fungal communities may be ecologically important in terms of ecosystem C and N dynamics.
EXCHANGE DYNAMICS OF REDOX-ACTIVE SELF-ASSEMBLING MIXED MONOLAYERS

The exchange dynamics as well as the desorption and displacement reactions of redox-active self-assembling monolayers based on transition-metal complexes of osmium and ruthenium have been studied. On the basis of results from the above-mentioned processes, it appears that the exchange dynamics are controlled by the rate of desorption via a dissociative mechanism. We have also made use of wave-shape analysis in terms of shifts in the formal potentials and widths of the voltammetric waves with changes in the surface coverage and monolayer composition. The presence of mixed monolayers (Os/Ru) results in an increased broadening of the voltammetric wave associated with the ruthenium complex relative to the case of a monolayer of the ruthenium complex alone which we ascribe to an enhanced degree of electrostatic repulsion. Also based on an analysis of the voltammetric response, we believe that the mixed monolayers are randomly distributed rather than being composed of discrete and separated phases.
Black Homeownership: The Role of Temporal Changes and Residential Segregation at the End of the 20th Century*

Objective. This study examines how the odds of a black renter becoming a homeowner changed during the 1990s, considering significant policy changes aimed at dismantling discriminatory barriers to nonwhite homeownership during that time period and various housing-market characteristics, including the level of residential segregation. Methods. This study uses geocoded data from the Panel Study of Income Dynamics and from the 1990 and 2000 Censuses to estimate an event-history model of transition into homeownership for black Americans. Results. The results of this study suggest that blacks benefited from the changing home-lending environment and were more likely to become homeowners during the 1990s. These improvements appear to be both absolute and relative to whites. This implies that the policy changes had some success. Nevertheless, blacks were significantly less likely to become homeowners during the study period—even after controlling for a variety of factors known to be associated with homeownership—suggesting that further reforms may be necessary to eradicate disparities in access to homeownership between whites and blacks. The analysis also shows that blacks residing in metro areas with the highest levels of racial isolation were significantly more likely to become homeowners than blacks residing in metro areas with the lowest levels of isolation. Conclusion. The study results show that the policy reforms of the 1990s likely had a salutary effect on black homeownership. The results also suggest that residential segregation matters to black homeownership in complex ways.
DIPYRIDOPHENAZINE COMPLEXES OF OS(II) AS RED-EMITTING DNA PROBES : SYNTHESIS, CHARACTERIZATION, AND PHOTOPHYSICAL PROPERTIES

Polypyridyl complexes of Os(II) bearing one dipyridophenazine (dppz) derivative and two ancillary ligands derived from bipyridine (bpy) or phenanthroline (phen) exhibit emission maxima at ∼740 nm and average excited-state lifetimes in the 10 ns range upon binding to DNA by preferential intercalation of the dppz ligand. A family of [Os(L^1)(L^2)(L^3)]^(2+) and [Os(L^1)_2(L^2)]^(2+) complexes with simple modifications in the ancillary phen or bpy ligands (L^1 and L^3) as well as the intercalating dppz ligand (L^2) was prepared. By cyclic voltammetry, electron-donating substituents on the ancillary ligands lowered the Os(3+/2+) reduction potential but did not affect the reduction potential of the dppz ligand. A methyl substituent at the 7-, 8-, or 6-position of the dppz ligand shifted the phenazine reduction toward the negative but did not affect the Os(3+/2+) potential. Absorption titrations indicated intercalative binding to DNA with high affinity (K_B ∼10^6 M^(-1)) for the family of complexes, although at high ratios (50:1) of base pairs to metal, complexes with ancillary 4,7-dimethylphenanthroline or 4,4‘-dimethylbipyridine ligands exhibit less hypochromism (26−27%) in the π−π* transition on the dppz ligand compared to complexes with 5,6-dimethylphenanthroline (30−37%) or the parent phen (31−35%). By steady-state and time-resolved emission spectroscopy, complexes bound to DNA by intercalation with substituents on the 4,7- or 4,4‘-positions of the ancillary phen or bpy displayed lower quantum yields for emission (Φ_(em)) compared to complexes with the parent phen, while complexes with methyl substituents on the dppz ligand had the greatest Φ_(em). Studies with poly d(AT), poly d(GC), and mixed-sequence DNA revealed that the emission yields are also sequence-dependent. Comparative luminescence studies in CH_2Cl_2 demonstrated that these effects arise from a combination of (i) the inherent sensitivity of the excited state to ligand structure and (ii) perturbations in DNA binding geometry introduced by substituents on the ancillary and intercalating ligands. Our results clarify the relationships between ligand architecture and emission yield and lifetime in the presence and absence of DNA and illustrate the utility of dppz complexes of Os(II) as luminescent probes for DNA.
Incompatibility between Flac, R386, and F:pSC101 recombinant plasmids: the specificity of F incompatibility genes.

Abstract The specificity of F incompatibility genes ( inc + ) has been studied with the F lac and R386 plasmids, members of the IncFI incompatibility group. Recently, two inc + regions, inc A (46.4–49.3F) and inc B (43.1–46.4F) were identified by cloning these F sequences onto pSC101 and subsequently demonstrating incompatibility of the recombinants with F lac . It is shown here that the F inc A + recombinant is incompatible with both F lac and R386 while the F inc B + recombinant is incompatible only with F lac . Also, a plasmid mutant is described that has reduced incompatibility against F lac and R386. The mutation is located on the Bam HI restriction fragment that contains the F inc A region. These genetic findings are consistent with the deduction of Palchaudhuri and Maas, based on heteroduplex analysis of IncFI plasmids, that placed the IncFI determinant in the 46.4–48.6F region. The findings also indicate that the F inc B + gene product, which has been implicated in negative control of F copy number, is specific for the F replicon.
Characteristic Fragmentation of Polysiloxane Monolayer Films by Bombardment with Monatomic and Polyatomic Primary Ions in TOF-SIMS

This study reports the characteristic fragmentation patterns from two polysiloxane polymers that form ordered overlayer on silver substrates. Results are compared for the bombardment of various monatomic and polyatomic projectiles of Cs+, C 60 + (10 keV), Bi 1 + , and Bi 3 + (25 keV) in the high mass range time-of-flight secondary ion mass spectrometry (TOF-SIMS) spectra. Results are reported from sub-monolayer (solution cast) coverages of poly(dimethylsiloxane)s with the number average molecular weights (Mn) of 2200 and 6140 Da, respectively, and Langmuir-Blodgett monolayers of poly(methylphenylsiloxane) with molecular weights (MW) from 600 and 1000 Da. For each film, Bi projectiles resulted in the emission of positive silver cluster ions from the substrate under the polymer overlayer and peaks corresponding to silver cluster ions with larger mass were observed by impact of polyatomic 25 keV Bi 3 + projectiles. In addition, depending on the change of energy of Bi 3 + , a different pattern of fragments was observed. With Cs+ and C 60 + impact, however, the emission of silver cluster ions was not detected. In the case of C 60 + impact for PDMS-6140, peaks corresponding to silver-cationized intact oligomers were not observed. In this paper, these results are explained by the possible bombardment mechanism for each projectile, based on its mass, energy, and split trajectories of the component atoms under the polyatomic impact.
Enumeration of periodic tetrahedral frameworks. II. Polynodal graphs

Abstract In a previous study, we developed a database of periodic 4-connected graphs [Zeit. Kristallogr. 212 (1997) 768]. The database was built using a symmetry constrained intersite bonding search (SCIBS) method. This method enumerates all possible 4-connected nets within each space group type given the number of unique tetrahedral vertices, nT. Approximately 107 graphs were obtained, mostly for nT = 1, 2. nT = 4 was achieved for some space groups that were rich in mirror symmetry. There was a combinatorial explosion of graphs with increasing nT in some space groups, which ultimately limited the method. The uninodal graphs, nT = 1, were refined by simulated annealing. A simple cost function was used that favoured a regular tetrahedral arrangement of neighbouring silicon atoms to emulate zeolite frameworks. Many plausible hypothetical uninodal zeolitic frameworks were reported. Since that report, we have improved the efficiency of the combinatorial search, and extended the range of our graph database to nT = 7 for some high mirror symmetry space groups. We have also implemented a more sophisticated Monte Carlo strategy for imbedding graphs in real space as an SiO2 composition. Plausible refinements are then further optimized using the GULP program. Presently, there are almost 1010 graphs in our database, and the number of plausible regular tetrahedral SiO2 frameworks identified now exceeds 100,000.
All-Electron Study of Gradient Corrections to the Local Density Functional in Metallic Systems

Using the all-electron Linearized Augmented Plane Wave (LAPW) method, we calculate the effect of including gradient corrections to the exchange correlation functional on the structural properties of the simple metal Al, transition metals Ta, W, Pt, and noble metals Cu, Ag, Au. For all the systems studied, the local density approximation (LDA) yields bond-lengths that are too short and bulk moduli that are too large. The generalized gradient functional introduced by Perdew and Wang (PW91) yields corrections that are in the right direction (larger bond-lengths and smaller bulk moduli), but it frequently overcompensates, particularly for the heavier elements. The PW 91 functional predicts the lattice constant and bulk modulus of Al and Cu more accurately than the LDA but yields values that are less accurate than the LDA for W, Pt, Au.
One solution of the pentagon problem

2. Let us try to understand how many parameters are needed in order to determine the pentagon. Let CD = a; let angle BCD = p; and let angle CDE = y. We know the line BE to be parallel to CD, and (since the area of triangle BCD is l), the distance between the lines BE and CD must be 2/a. The parameters a, j3, and y, together with this parallelism and separation distance, consequently determine points B and E.
Reconfigurable terahertz metamaterial device with pressure memory

We demonstrate a liquid metal-based reconfigurable terahertz (THz) metamaterial device that is not only pressure driven, but also exhibits pressure memory. The discrete THz response is obtained by injecting eutectic gallium indium (EGaIn) into a microfluidic structure that is fabricated in polydimethylsiloxane (PDMS) using conventional soft lithography techniques. The shape of the injected EGaIn is mechanically stabilized by the formation of a thin oxide surface layer that allows the fluid to maintain its configuration within the microchannels despite its high intrinsic surface energy. Although the viscosity of EGaIn is twice that of water, the formation of the surface oxide layer prevents flow into a microchannel unless a critical pressure is exceeded. Using a structure in which the lateral channel dimensions vary, we progressively increase the applied pressure beyond the relevant critical pressure for each section of the device, enabling switching from one geometry to another (split ring resonator to closed ring resonator to an irregular closed ring resonator). As the geometry changes, the transmission spectrum of the device changes dramatically. When the external applied pressure is removed between device geometry changes, the liquid metal morphology remains unchanged, which can be regarded as a form of pressure memory. Once the device is fully filled with liquid metal, it can be erased through the use of mechanical pressure and exposure to acid vapors.
Bronchial-atrial fistula after lung transplant resulting in fatal air embolism

We describe a rare case of fatal air embolism in a patient in whom a left atrial-bronchial fistula developed 1 month after single lung transplant. The cause was a combination of mediastinal infection and bronchial necrosis.
Arthroscopic stabilization of type II SLAP lesions using an absorbable tack

Abstract Purpose: To document the outcomes of arthroscopic stabilization of Snyder type II SLAP (superior labrum, anterior and posterior) lesions, using a bioabsorbable tack. Type of Study: A case series. Methods: Twenty-five SLAP lesions were repaired arthroscopically using a bioabsorbable tack. There were 22 recreational, 2 high school, and 1 professional athlete in this group. Shoulder function was surveyed at a mean follow-up of 35 months (range, 24 to 51 months) using the UCLA and ASES shoulder scoring algorithms. Results: Shoulder function improved in 24 of the 25 cases. Follow-up UCLA scores averaged 32 points with 9 patients scoring as excellent, 13 good, 2 fair, and 1 poor, for an overall success rate of 88%. ASES shoulder scores similarly improved from a preoperative average of 45 points to a postoperative average of 92. All but 2 of the athletes had returned to their preinjury level of sports participation. Conclusions: Detachment of the superior labrum from the glenoid is recognized as a problematic injury in throwing athletes and others who engage in repetitive overhead activities. We conclude from our experience that using an absorbable tack to repair type II SLAP lesions is an effective treatment, even in athletes with high demands and expectations for shoulder function. Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 1 (January), 2001: pp 19–24
Transient Diffusion and Conduction in Heterogeneous Media: Beyond the Classical Effective-Medium Approximation

In this paper steady-state and transient diffusion and conduction in heterogeneous media, such as composite solids, are studied. The heterogeneities are of percolation type in the sense that a randomly-selected fraction of the system does not allow transport to take place. We present several new extensions of the classical effective-medium approximation (EMA) for diffusion and conduction in regular network models of heterogeneous media, including an EMA for topologically-random networks, such as the Voronoi network, for which we introduce a novel stochastic Green function, and a cluster (higher order) EMA for transient diffusion and other dynamical properties of heterogeneous media. In all cases the predictions are compared with the results of Monte Carlo simulations.
Pileup rejection in pulsed beam experiments

Abstract A simple method of pileup rejection suitable for pulsed beams is described, and its sensitivity and time resolution are analyzed.
The weight-average tube number and the weight-average rate factor in countercurrent distribution

Abstract Analysis of each tube in a zonal countercurrent distribution experiment can be used, after any arbitrary number of transfers and with any arbitrary partition coefficient, to determine accurately the weight-average tube number for a single ideal solute, from which the partition coefficient may be determined with similar accuracy. For polydisperse ideal solutes, this type of experiment leads to weight-average values for the weight-average tube number, related directly to weight-average rate factor (RF) numbers. For chemically interacting systems, a meaningful “descending boundary” counter-current distribution experiment may be performed. In such an experiment, the weight-average RF number is characteristic of the composition in the plateau region, it is related directly to the first moment in the concentration gradient distribution, and it describes the rate at which solute mass is being transferred through the plateau region. The variation of the weight-average RF number with the composition of the original solution may be used under optimal conditions to obtain quantitative information about chemical equilibrium in chemically interacting systems.
Does State Failure Cause Terrorism? An Empirical Analysis (1999–2008)

A developed-world consensus ties state failure to new and serious international insecurity. But that conclusion rests upon an uncertain foundation; insights into the nature and intensity of failure...
Expert judgment in a heterogeneous task environment

Recent times have seen an explosion of research on the intersection between rules, models, heuristics, and ecological task structure. Many groups have worked to connect loose strategies and findings into a more cohesive theory of judgment, specifying the particular ecologies under which various strategies work well or not. However, the majority of this research has been conducted under the assumption that judgment environments are homogeneous in composition. This paper reports an experiment in which the judgment task of interest possesses a heterogeneous structure, with different subsets of the task environment governed by different rules or weighting functions. Results reveal that experts were able to perform the task well by taking advantage of the heterogeneous nature of the task ecology, selectively choosing and adapting their use of strategies according to how well each operates in the different sub-ecologies of the task environment. Implications for understanding and supporting expert judgment in op...
Morphologic analysis of upper lip area following maxillary osteotomy via the tunneling approach

Preservation of favorable upper lip morphology is a critical factor in assessing the success of maxillary osteotomy surgery. Unesthetic postsurgical lips often appear thin and tight, with the vermilion border shortened and rolled inward. Clinical observation of patients who had undergone total maxillary alveolar process osteotomies by means of vertical buccal incisions and a tunneling approach suggests that presurgical lip morphology is minimally changed. This study investigates the presence and degree of change in upper lip morphology following this technique. Pre- and postoperative cephalometric radiographs of ten patients were compared by superimposition of acetate tracings on cranial base landmarks. Cross-sectional lip area was calculated by compensating polar planimetry presurgically and at four intervals following intervention: 1 to 3 days, 1 to 3.5 months, 6 to 9 months, and more than 10 months. Analysis showed the cross-sectional upper lip area, compared to the presurgical baseline, to be as follows: Immediately following surgery, the area increased by a mean of 27.8% (range, 15.0% to 36.9%; SE = 4.72). At 1 to 3.5 months postsurgery, the increase was reduced to 3.3% (range, 0 to 7.7%; SE = 0.82). At 6 to 9 months, lip area remained minimally increased, at + 0.78% (range, -5.0% to 7.6%; SE = 1.68). At 10 months or longer, the mean increase from preoperative values was 0.61% (range, -6% to 6.4%; SE = 1.38). The results of this study indicate that the upper lip cross-sectional area returns to its presurgical value at 6 months following surgery and remains constant at subsequent measurements. The performance of maxillary surgery with this flap design appears to preserve presurgical lip morphology.
Generalized reverse theorems for multipass applications in matrix optics

The reverse theorem that governs backward propagation through optical systems represented by transfer matrices is examined for various matrix theories. We extend several reverse theorems to allow for optical systems represented by matrices that may or may not be unimodular and that may be 2 × 2 or take on an augmented 3 × 3 form. As an example, we use the 3 × 3 form of the reverse theorem to study a laser with intracavity misaligned optics. It is shown that, by tilting one of the laser’s mirrors, we can align the laser output arbitrarily, and the mirror tilt angle is calculated.
Energetic cost of producing cyclic muscle force, rather than work, to swing the human leg

We compared two hypothesized energetic costs for swinging the human leg quickly. The first cost is to perform mechanical work on the leg, and the second is to produce muscle force cyclically at high frequencies. Substantial metabolic energy is expended to perform isolated leg swinging, especially at rates greater than the leg's natural pendular frequency. To determine whether the production of muscle force contributes to this cost, we measured oxygen consumption in human subjects (N=6) performing isolated swinging of the leg at frequencies 0.7-1.1 Hz. Amplitude of swing was varied as a function of frequency so that the rate of positive mechanical work performed on the leg remained fixed. We expected that the cost of producing force would increase, in contrast to the cost of performing work. The results showed that average rate of positive mechanical work performed on the leg remained nearly constant as a function of frequency, at 0.073+/-0.014 W kg(-1). Net metabolic rate, however, increased by 53%, from 0.66 W kg(-1) to 1.01 W kg(-1). Work may be performed on the leg and with a proportional metabolic cost, but it cannot explain the substantial increases observed here. Metabolic energy expenditure appears to increase in proportion with muscle force or torque, and in inverse proportion to duration of force. This energetic cost may be associated with cyclical calcium transport, where rate-limiting of crossbridge attachments may require greater sarcoplasmic calcium concentration at high frequencies of leg swinging to produce the same amplitude of muscle force. It may also be relevant to moving the legs back and forth relative to the body during walking.
Risk factor model to predict venous thromboembolism in hospitalized medical patients

BACKGROUND: The Joint Commission requires that all medical inpatients be assessed for venous thromboembolism (VTE) risk, but available risk stratification tools have never been validated. METHODS: We conducted a retrospective cohort study of patients age ≥18 years, admitted to 374 US hospitals in 2004–2005, with a primary diagnosis of pneumonia, heart failure, chronic obstructive pulmonary disease (COPD), stroke, and urinary tract infection, and length of stay ≥3 days. Subjects were randomly assigned (80/20) to a derivation or validation set. We then assessed VTE (International Classification of Diseases, Ninth Revision [ICD-9] code plus diagnostic test plus treatment), patient demographics, 21 potential risk factors, and other comorbidities. We created a VTE risk stratification tool using multivariable regression modeling and applied it to the validation sample. RESULTS: Of 242,738 patients, 612 (0.25%) patients fulfilled our criteria for VTE during hospitalization, and an additional 440 (0.18%) were readmitted for VTE within 30 days (overall incidence of 0.43%). In the multivariable model, age, sex, and 10 additional risk factors were associated with VTE. The strongest risk factors were inherited thrombophilia (OR 4.00), length of stay ≥6 days (OR 3.22), inflammatory bowel disease (OR 3.11), central venous catheter (OR 1.87), and cancer. In the validation set, the model had a c-statistic of 0.75 (95% CI 0.71, 0.78). Deciles of predicted risk ranged from 0.11% to 1.46% with observed risk over the same deciles from 0.17% to 1.81%. CONCLUSIONS: The risk of symptomatic VTE in general medical patients is low. A risk factor model can identify those at sufficient risk to warrant pharmacologic prophylaxis. Journal of Hospital Medicine 2011. © 2011 Society of Hospital Medicine.
Assessing the dynamics and ecology of marine picophytoplankton: The importance of the eukaryotic component

We assess population dynamics of picophytoplankton groups (#2 mm diameter; Prochlorococcus, Synechococcus, and picoeukaryote) at a Pacific Ocean coastal site in the Southern California Bight. Weekly sampling (August 2000 to January 2002), dilution experiments, and flow cytometric analysis were combined with an instrument-specific calibration for cell size determination, allowing biovolume and carbon biomass estimation. Synechococcus was almost always numerically dominant, accounting for 60 6 12% of the total picoplankton cells over time. It had moderately high growth rates (0.52‐0.86 d 21 21 ).
Control of nonlinear system with input saturation based on Gaussian potential function network

The authors present a novel approach to the neural-network-based control of a nonlinear system, or in particular for the neural-network-based regulation of a nonlinear system subject to input saturation. This approach is based on (1) the training of a Gaussian potential function network (GPFN) to model nonlinear system dynamics based on the hierarchically self-organizing learning (HSOL) algorithm, and (2) the planning of a path from the initial state to the goal state which ensures the state reachability under input saturation and the satisfaction of performance criteria. Path planning is done in the regulatable region associated with the feasible state transition region based on a potential field method. The advantage of using GPFN with HSOL compared to backpropagation networks is due to the capability of HSOL to recruit a required number of Gaussian hidden units automatically and incrementally by monitoring network performance. This makes it possible to overcome the structural limitations of a network and also the local minima problem in learning. >
A Novel Role for Viral-Defective Interfering Particles in Enhancing Dendritic Cell Maturation

Dendritic cell (DC) maturation is a crucial event in the development of adaptive immune responses that confer long-lasting protection against reinfection with the same virus. Sendai virus strain Cantell has a particularly strong ability to mature DCs independently of type I IFNs and TLR signaling, currently the best-described pathways for the induction of DC maturation. In this study, we demonstrate that defective-interfering (DI) particles present in Sendai virus-Cantell stocks are required for its robust DC maturation ability. DI particles contain incomplete genomes that are unable to replicate unless the viral polymerase is supplied by coinfection with complete virus. Accordingly, the improvement in the virus-induced maturation of DCs provided by DI particles requires standard virus coinfection and likely results from increased production of dsRNA replication intermediaries. This unique ability of DI particles to stimulate DC maturation cannot be mimicked by simply increasing the dose of standard virus. Furthermore, viruses with weak DC maturation abilities can be converted into potent DC stimulators with the addition of DI particles, supporting a potential application for DI particles as a novel natural adjuvant for viral immunizations.
Rapid cellular phenotyping of human pluripotent stem cell-derived cardiomyocytes using a genetically encoded fluorescent voltage sensor.

Summary In addition to their promise in regenerative medicine, pluripotent stem cells have proved to be faithful models of many human diseases. In particular, patient-specific stem cell-derived cardiomyocytes recapitulate key features of several life-threatening cardiac arrhythmia syndromes. For both modeling and regenerative approaches, phenotyping of stem cell-derived tissues is critical. Cellular phenotyping has largely relied upon expression of lineage markers rather than physiologic attributes. This is especially true for cardiomyocytes, in part because electrophysiological recordings are labor intensive. Likewise, most optical voltage indicators suffer from phototoxicity, which damages cells and degrades signal quality. Here we present the use of a genetically encoded fluorescent voltage indicator, ArcLight, which we demonstrate can faithfully report transmembrane potentials in human stem cell-derived cardiomyocytes. We demonstrate the application of this fluorescent sensor in high-throughput, serial phenotyping of differentiating cardiomyocyte populations and in screening for drug-induced cardiotoxicity.