cssi/SciSciGPT-SciSciNet huggingface dataset:
Organizational Change Efforts: Methodologies for Assessing Organizational Effectiveness and Program Costs Versus Benefits

This article presents two methodologies for evaluating organizational effectiveness and program costs versus benefits in organizational change programs. The first methodology describes the development of a standardized approach for identifying, defining, and measuring indicators of work behavior and performance that fit a broader concept of organizational effectiveness than traditional production and financial outcomes. The second methodology describes methods used to estimate the costs and benefits of work innovation or change programs, in terms of both economic and social utility. A framework for assessing organizational change is provided from which behavior and financial results can be estimated and compared with program costs to develop a cost-benefit ratio. Both methodologies are used to monitor and assess an extensive longitudinal quality of work life experiment.
Noninvasive forward-scattering system for rapid detection, characterization, and identification of bacterial colonies

Bacterial contamination of food products puts the public at risk and also generates a substantial cost for the food-processing industry. One of the greatest challenges in the response to these incidents is rapid recognition of the bacterial agents involved. Only a few currently available technologies allow testing to be performed outside of specialized microbiological laboratories. Most current systems are based on the use of expensive PCR or antibody-based techniques, and require complicated sample preparation for reliable results. Herein, we report our efforts to develop a noninvasive optical forward-scattering system for rapid, automated identification of bacterial colonies grown on solid surfaces. The presented system employs computer-vision and pattern-recognition techniques to classify scatter patterns produced by bacterial colonies irradiated with laser light. Application of Zernike and Chebyshev moments, as well as Haralick texture descriptors for image feature extraction, allows for a very high recognition rate. An SVM algorithm was used for classification of patterns. Low error rates determined by cross-validation, reproducibility of the measurements, and robustness of the system prove that the proposed technology can be implemented in automated devices for bacterial detection.
Effect of Dysthymia on Receipt of HAART by Minority HIV‐infected Women

BACKGROUND: Receipt of highly active antiretroviral therapy (HAART) differs by gender and racial/ethnic group and may reflect an effect of mood disorders.
Diuraphis Aizenberg (Hom., Aphididae): key to apterous viviparous females, and review of Russian language literature on the natural history of Diuraphis noxia (Kurdjumov, 1913)

This paper compiles and summarizes a great deal of extremely pertinent Russian language literature (most of which has remained little known and inaccessible to western scientists) covering virtually all of the basic early reports of the Russian wheat aphid, Diuraphis noxia (Kurdjumov, 1913), and traces the evolution of this insect into one of the world's most damaging pests of small grains. A longstanding error in the authorship of D. noxia is corrected. An original taxonomic key to the apterous vivipara of species of Diuraphis is proposed. Various old-world parasitoid, predator, and native host plant associations with Diuraphis species are described from the literature, and a number of potentially useful aphidophagous insects are identified and collection sites recommended. Zusammenfassung Diuraphis Aizenberg (Hom., Aphididae): Bestimmungsschlussel fur die ungeflugelten, viviparen Weibchen sowie Uberblick zur russischsprachigen Literatur uber die Bionomie von Diuraphis noxia (Kurdjumov, 1913) Die Arbeit fast einen grosen Teil der russischsprachigen Literatur (die uberwiegend in westlichen Landern wenig bekannt und erreichbar ist) uber die russische Weizenblattlaus Diuraphis noxia (Kurdj.) zusammen und verfolgt die Entwicklung dieser Blattlaus zu einem der grosten Getreideschadlinge der Welt. Ein langandauernder Irrtum uber die Urheberschaft dieser Spezies wird korrigiert. Es wird ein eigener Bestimmungsschlussel uber die ungeflugelten Viviparen der Gattung Diuraphis aufgestellt. Die verschiedenen altweltlichen Parasitoiden und Pradatoren sowie die ursprungliche Wirtspflanzen-Assoziation mit Diuraphis-Arten werden an Hand der Literatur wiedergegeben. Schlieslich wird eine Anzahl moglicherweise nutzbarer Aphidophagen betrachtet.
The singly constrained assignment problem: an AP basis algorithm

This manuscript presents a specialized primal simplex algorithm to obtain near optimal integer solutions for the singly constrained assignment problem. An optimal solution for the continuous relaxation of the problem is obtained by generalizing the alternating basis algorithm of Barr, Glover, and Klingman for the pure assignment problem. Near optimal integer solutions are obtained by pivoting into the optimal basis the slack variable associated with the side constraint. Our empirical analysis indicated that for our test problems the soft-ware implementation of this algorithm was six times faster than CPLEX and four times faster than NETSIDE (a specialized code for network problems with side constraints). The integer solutions obtained in our tests were typically within 2% of the optimum of the continuous relaxation.
An Infrared Study of the Interactions of CO and CO2 with Cu/SiO2

Abstract The adsorption of CO and CO2 on Cu/SiO2 have been investigated by infrared spectroscopy. CO adsorbs on Cu with a heat of adsorption of 8.4 kcal/mol, whereas CO2 weakly adsorbs on both Cu and SiO2 with a heat of adsorption of 6.9 kcal/mol. As much as 24% of the adsorbed CO2 is associated with Cu, and the rest with the silica support. On freshly reduced Cu/SiO2, adsorbed CO exhibits an infrared band 2103 cm−1 whereas CO2 exhibits a band at 2340 cm−1 when adsorbed on both SiO2 and Cu surfaces. A band at 2118 cm−1 is also observed during CO2 exposure. This feature is attributable CO associated with Cu+ formed via the dissociation of CO2 into COS and OS. The extent of CO2 dissociation on Cu is measured to be about 20%. During CO2 exposure the coverage of adsorbed CO increases rapidly, goes through a maximum, and then decays. This transient is attributable to the competition of CO and CO2 for Cu sites. The effects on the CO2 dissociation transient of temperature, pressure, space velocity, catalyst preoxidation, and H2 addition can be explained with the proposed mechanism.
Measurement of guinea pig eosinophil major basic protein by radioimmunoassay.

Abstract Major basic protein (MBP)‡ was measured by radioimmunoassay (RIA) using 131 I-MBP, rabbit anti-MBP, and burro anti-rabbit IgG. Two critical features of the assay were: (1) alkylation of the MBP with iodoacetamide prior to radioiodination and (2) inclusion of another basic protein, either protamine or histone, in the phosphate buffer. Freshly isolated non-alkylated MBP was immunologically deficient when compared to alkylated or reduced and alkylated MBP, but its reactivity could be restored by reduction with dithiothreitol and alkylation. Polymerized MBP also showed reduced immunoreactivity which could be regenerated by reduction and alkylation. MBP activity was rapidly destroyed at 56°C, but it could be lyophilized, and it survived treatment with 6 M guanidinium hydrochloride (GuHCl). After initial reduction and alkylation in the absence of dissociating solvents, subsequent reduction and alkylation in 6 M GuHCl renders the protein unreactive. MBP levels in normal guinea pig serum were less than 5 ng/ml and were not elevated in sera from guinea pigs parasitized with Trichiwlla spiralis and having peripheral blood eosinophilia. Muscle extracts from Trichinella infected animals showed significantly higher levels of MBP activity than normal controls. MBP was measurable in extracts of untreated eosinophils, but reduction and alkylation of these extracts increased MBP activity several fold. Extracts of purified eosinophils averaged 1.13 × 10 −3 ng MBP per cell. The RIA permits detection of MBP in body fluids and tissues at levels as low as 2 ng/ml. The RIA is useful in assessing increased or decreased levels of MBP activity in samples from experimental animals when compared to samples from controls.
Multigranular Molecular Dynamics Simulations of Polymer Melts Using Multibody Algorithms

In a multigranular approach for modeling molecular dynamics of polymer melts, different sections of the simulation box are modeled at different levels of detail viz. as particles, flexible bodies or rigid bodies. This approach eliminates high frequency localized motion while maintaining low frequency global conformational motion. This allows for longer integration time steps thus decreasing computational time. In this paper, we discuss our efforts to develop a consortium of dynamics algorithms capable of efficiently generating and solving the equations of motion at all three levels of modeling on a common software platform. A bead spring model of the polymer melt moving under the influence of truncated Lennard-Jones potential under periodic boundary conditions is pursued. Implementation issues and results from a test case consisting of 32 polymer chains of 16 beads each are presented. The paper also discusses the parallel implementation of this problem using MPI.Copyright © 2005 by ASME
Overview of Alzheimer's disease

In conclusion, many researchers from multiple disciplines are addressing AD at many levels, ranging from prevention, to cellular alterations, to treatment modalities, and coping and care giving with the consequences of the ravages left by the disease. Although much has been learned in the last several decades of active research, much remains to be learned. In its current status, AD is a chronic disease without a cure, which provides ample opportunities for nursing management throughout the course progression.
An anaerobic titration assembly for spectrophotometric use

Abstract An anaerobic titration apparatus capable of titrations of 2.5 ml of solution with microliter quantities of titrant is described. Numerous samples can be titrated with the same stock solution and back titrations with different titrants are possible. No detectable O 2 leaks (5 mμmoles of O 2 or greater) were observed over a 6 day period. Biochemical applications of the apparatus are discussed.
OPTIMIZATION OF PASSIVE AND ACTIVE NON-LINEAR VIBRATION MOUNTING SYSTEMS BASED ON VIBRATORY POWER TRANSMISSION

Abstract While significant non-linear behavior has been observed in many vibration mounting applications, most design studies are typically based on the concept of linear system theory in terms of force or motion transmissibility. In this paper, an improved analytical strategy is presented for the design optimization of complex, active of passive, non-linear mounting systems. This strategy is built upon the computational Galerkin method of weighted residuals, and incorporates order reduction and numerical continuation in an iterative optimization scheme. The overall dynamic characteristics of the mounting system are considered and vibratory power transmission is minimized via adjustment of mount parameters by using both passive and active means. The method is first applied through a computational example case to the optimization of basic passive and active, non-linear isolation configurations. It is found that either active control or intentionally introduced non-linearity can improve the mount's performance; but a combination of both produces the greatest benefit. Next, a novel experimental, active, non-linear isolation system is studied. The effect of non-linearity on vibratory power transmission and active control are assessed via experimental measurements and the enhanced Galerkin method. Results show how harmonic excitation can result in multiharmonic vibratory power transmission. The proposed optimization strategy offers designers some flexibility in utilizing both passive and active means in combination with linear and non-linear components for improved vibration mounts.
A small molecule compound inhibits AKT pathway in ovarian cancer cell lines.

Abstract Background and objective. Overactivation of AKT1 and gene amplification of AKT2 are frequently detected in ovarian cancer. Activated AKT kinases provide a cell survival signal that may confer resistance to apoptosis induced by conventional therapies in cancer cells. Therefore, development of potent inhibitors that block AKT pathway is an attractive therapeutic strategy for treating ovarian carcinoma. Methods. Ovarian cancer cell lines, A2780, MDAH2774, OVCAR-8, Caov-3, and normal murine fibroblasts (NIH3T3) were used. Cells were treated with different doses of a non-peptide small molecule compound, 9-methoxy-2-methylellipticinium acetate (termed API-59-OME) that potentially inhibit AKT pathway. Kinase assays and the phosphorylation of AKT, GSK-3α/β, PDK1, ERK1/2, SGK, p38, FAK, EGFR, JAK2, PKC isoforms, and the cleavage of poly (ADP-ribose) polymerase (PARP) were examined in treated and untreated cell lines. Further, cells treated with API-59-OME were analyzed for induction of apoptosis using sub-G1 profile with propidium iodide staining. Results. API-59-OME inhibited AKT kinase activity but did not inhibit ERK or JNK kinase activities in A2780, MDAH2774, and OVCAR-8 cell lines. API-59-OME did not reduce phosphorylation of other protein kinases in these cell lines. API-59-OME induced apoptosis and the cleavage of PARP in A2780, MDAH2774, and OVCAR-8 ovarian cancer cell lines that express elevated levels of phosphorylated AKT. In contrast, in Caov-3 and NIH3T3 cell lines, which lack constitutive AKT activity, API-59-OME only had minimal effect to induce apoptosis. Conclusion. These data suggest that API-59-OME may be a potent agent to target constitutively activated AKT pathway in ovarian cancer cells.
Abandoned Underground Storage Tank Location Using Fluxgate Magnetic Surveying: A Case Study

In 1993, during the removal of a diesel and a gasoline underground storage tank at the municipal garage of the Village of Kohler, Sheboygan County, Wisconsin, soil testing revealed environmental contamination at the site. A site investigation revealed the possibility of a second on-site source of petroleum contamination. Limited historical data and the present usage of structures within the suspected source area precluded the use of most invasive sampling methods and most geophysical techniques. A fluxgate magnetometer survey, followed by confirmatory excavation, was conducted at the site. The fluxgate magnetometer survey identified nine possible magnetic anomalies within the 18 × 25 m area. The subsequent excavation near the anomalies revealed the presence of five paired and two individual 2000 L underground storage tanks. The fluxgate magnetometer survey, although affected by the proximity of buildings, was able to detect the buried tanks within 3 m of the brick structures, using a 1.5 × 1.5 m sampling array.
MO-EE-A1-03: A New Technique for Rectal Endocavitary Radiotherapy: Treatment with an Electronic Brachytherapy Source

Purpose: To present the design aspects and clinical implementation of electronic brachytherapytreatment for early stage rectal adenocarcinoma. A dosimetric comparison between the historically used RT‐50 (Papillon technique) unit and a customized system utilizing the Xoft electronic brachytherapysource is investigated. Materials and Methods: Two proctoscope cones were manufactured by ElectroSurgical Instruments (ESI). Four custom surface applicators were manufactured by Xoft, Inc. and are designed to fit and interlock with the proctoscope cones from ESI. Dose rate, Half Value Layer (HVL), Percentage Depth Dose (PDD), and Exposure measurements were made with both the RT‐50 and the Xoft systems. Results: The Xoft system has a lower dose rate than the RT‐50. The average Xoft dose rate is approximately 2 Gy/min while the RT‐50 is 10–11Gy/min. Typical patient treatments are 20–30 Gy, resulting in a 10–15 minute treatment time with the new system compared to 2–3 minutes with the RT‐50. The HVLs and PDDs between the two systems are comparable resulting in similar doses to the target. The exposure rate in the direction of the beam are higher with the Xoft system. Lateral to the beam, the exposure rates are lower, most likely due to higher attenuation in the new stainless steel proctoscope. Conclusions: The RT‐50 unit is an older radiotherapy machine with limited replacement parts. Additionally the unit is cumbersome to use in an operating room due to its large size. The use of a custom‐designed proctoscope and commercial Xoft surface applicators allows delivery of a well established treatment with the ease of a modern radiotherapy device. While the treatment time is longer with Xoft, the treating staff may stand farther away from the radiation producing device, thus reducing radiation exposure. The availability of a modern radiotherapy system may result a renewed interest in performing endocavitary radiation therapy.
Rotating-disk method for determining cutaneous metabolism

Since design and evaluation of topical dosage forms should account for both skin permeation and cutaneous metabolism, an in vitro system was formulated to determine the metabolic component of viable guinea pig skin utilizing the diffusion layer property of the rotating disk. The drug investigated was vidarabine, an antiviral agent, which was rapidly metabolized to 9-β-D-arabinofuranosylhypoxanthine. The aqueous diffusion coefficient of the drug was determined by the capillary cell method. The rotating-disk system was standardized using benzoic acid. The dorsal skin of a guinea pig was removed after shaving, and the epidermal section was excised by a keratome. After the section was mounted on the stainless steel disk with a tissue adhesive, the preparation was immersed in a 10-ml beaker containing 5 ml of drug solution at 37°. At suitable intervals, samples were withdrawn, separated by TLC, and assayed by liquid scintillation. The enzyme rate constant was 1.54 × 10−1 sec−1.
Fecal Sterol and Bile Acid Biomarkers: Runoff Concentrations in Animal Waste-Amended Pastures

Nonpoint source pollution is the leading remaining cause of water quality problems. The extent of NPS pollution is often more difficult or expensive to monitor at the point(s) of origin, as compared to monitoring of point sources. This study evaluated the hypothesis that animal manure (chicken, cow, horse, and pig) applied to pasture contribute fecal sterols and bile acids to runoff. The study also assessed the potential benefit of fecal sterols and bile acids as biomarkers in distinguishing fecal pollution and its sources. Fecal sterol and bile acid concentrations were determined in flow-weighted composite runoff samples collected from 2.4 × 6.1 m plots (n = 3) amended with manure. Runoff was generated from simulated rainfall (152 mm.h−1). Runoff samples from manure-amended plots showed high concentrations of fecal sterol (ranged from 13 ± 1 to 1,287 ± 183) and bile acid (ranged from 24 ± 1 to 2,251 ± 248) biomarkers. The profiles of fecal sterols and bile acids in runoff samples were similar to those of fresh manure for all selected animals. For runoff and fresh manure, chenodeoxycholic acid, deoxycholic acid, epicoprostanol, and hyodeoxycholic acid were consistent biomarkers for chicken, cow, horse, and pig, respectively, suggesting that sterols and bile acids can be used to identify sources and occurrence of fecal matter in water and sediments.
Reverse Ventricular Remodeling and Improved Ventricular Compliance After Heart Transplantation in Infants and Young Children

After heart transplantation (HT) in infants and young children, environmental and intrinsic factors may lead to changes in the geometry and compliance of the donor heart. Serial demographic, clinical, hemodynamic, and echocardiographic data were obtained from HT recipients younger than 4 years of age. Echocardiographic chamber measurement z-scores were compared using recipient body surface area from the time of HT to 1 week, 3 months, and last follow-up visit. Left ventricular end-diastolic volume (LVEDV) z-scores were correlated with pulmonary capillary wedge pressure (PCWP) at each time point. Heart transplantation was performed for 13 children between March 2009 and December 2012, 9 of whom (69 %) were boys. The median age at HT was 8 months (range, 4–43 months), and the mean follow-up period was 13 ± 7 months. Left ventricular end-diastolic dimension z-scores decreased significantly (p = 0.03) between HT and 1 week, then increased from 1 week to 3 and 12 months. (−1.32 ± 1.7, −0.71 ± 1.8, 0.41 ± 2.1, 0.79 ± 2.3, respectively). A positive relationship (R2 = 0.48) between the LVEDV z-score and PCPW was present at the last follow-up visit. For infants and young children, the allograft demonstrates appropriate growth by 1 year after HT. Left ventricular compliance improves over time.
Dynamic Stability of a Translating Vehicle with a Simple Sling Load

A system consisting of helicopter with a singly tethered load is modeled as two particles connected by an inextensible link. The nonlinear equations of motion are linearized about a steady level flight condition, and it is shown that the perturbation equations separate into longitudinal and lateral/directional sets. For some selected parameter values, the modes are extracted and interpreted. Generally, instability will arise if the mass of the load is greater than the mass of the helicopter, or, if the tether length exceeds a critical value. Typically, this critical length is far in excess of reasonable values.
Thermodynamic parameters for an expanded nearest-neighbor model for the formation of RNA duplexes with single nucleotide bulges.

Thirty-four RNA duplexes containing single nucleotide bulges were optically melted, and the thermodynamic parameters ΔH°, ΔS°, ΔG° 37, and TM for each sequence were determined. Data from this study were combined with data from previous thermodynamic data [Longfellow, C. E., Kierzek, R., and Turner, D. H. (1990) Biochemistry 29, 278−85] to develop a model that will more accurately predict the free energy of an RNA duplex containing a single nucleotide bulge. Differences between purine and pyrimidine bulges as well as differences between Group I duplexes, those in which the bulge is not identical to either neighboring nucleotide, and Group II duplexes, those in which the bulge is identical to at least one neighboring nucleotide, were considered. The length of the duplex, non-nearest-neighbor effects, and bulge location were also examined. A model was developed which divides sequences into two groups: those with pyrimidine bulges and those with purine bulges. The proposed model for pyrimidine bulges predict...
Semi-automated hydrophobic interaction chromatography column scouting used in the two-step purification of recombinant green fluorescent protein.

Background Hydrophobic interaction chromatography (HIC) most commonly requires experimental determination (i.e., scouting) in order to select an optimal chromatographic medium for purifying a given target protein. Neither a two-step purification of untagged green fluorescent protein (GFP) from crude bacterial lysate using sequential HIC and size exclusion chromatography (SEC), nor HIC column scouting elution profiles of GFP, have been previously reported. Methods and Results Bacterial lysate expressing recombinant GFP was sequentially adsorbed to commercially available HIC columns containing butyl, octyl, and phenyl-based HIC ligands coupled to matrices of varying bead size. The lysate was fractionated using a linear ammonium phosphate salt gradient at constant pH. Collected HIC eluate fractions containing retained GFP were then pooled and further purified using high-resolution preparative SEC. Significant differences in presumptive GFP elution profiles were observed using in-line absorption spectrophotometry (A395) and post-run fluorimetry. SDS-PAGE and western blot demonstrated that fluorometric detection was the more accurate indicator of GFP elution in both HIC and SEC purification steps. Comparison of composite HIC column scouting data indicated that a phenyl ligand coupled to a 34 µm matrix produced the highest degree of target protein capture and separation. Conclusions Conducting two-step protein purification using the preferred HIC medium followed by SEC resulted in a final, concentrated product with >98% protein purity. In-line absorbance spectrophotometry was not as precise of an indicator of GFP elution as post-run fluorimetry. These findings demonstrate the importance of utilizing a combination of detection methods when evaluating purification strategies. GFP is a well-characterized model protein, used heavily in educational settings and by researchers with limited protein purification experience, and the data and strategies presented here may aid in development other of HIC-compatible protein purification schemes.
Reach-through claims for drug target patents: Rx for pharmaceutical policy.

Recognizing the value of the discovery and validation of new pharmaceutical targets would be a major step forward for pharmaceutical policy.
Abnormal ascospore morphology in the bud mutant of Neurospora tetrasperma

A recessive ascospore mutant of Neurospora tetrasperma, named bud, was isolated from a wild-collected heterokaryotic strain with four different nuclear components. bud segregates as a single mendelian gene. When bud is homozygous, meiosis is apparently normal but postmeiotic events are not. Abnormal orientation of spindles at the postmeiotic mitosis often results in failed pair-wise association of nuclei and their irregular distribution along the length of the ascus prior to spore delimitation. Consequently, many asci cut out more than four ascospores; some contain no nuclei while others contain more than two. The most dramatic effect of bud is on ascospore delimitation itself. Many ascospores are irregularly shaped and are often interconnected, because of incomplete spore delimitation. Ascospores also show one or two lobes or bud-like extensions of varying sizes. Over 75% of ascospores from bud x bud remain white or tan and are inviable. The interaction of bud with a dominant Eight-spore mutant (E) was examined in both heterozygous and homozygous crosses. When both bud and E are heterozygous, bud has no effect on ascospore delimitation or on the phenotype of E because bud is recessive; many asci produce 5-8 ascospores just as in E x E(+). And when bud is homozygous and E is heterozygous, ascospore delimitation is less affected than when E is absent. Moreover, when both bud and E are homozygous, the effect on ascospore development is less extreme than when E is homozygous singly.
A preliminary comparison of Cantonese and American‐English as taste languages

Groups of monolingual American-English speaking Americans of Chinese descent were compared with Cantonese/American-English bilingual Chinese living in America to examine their taste descriptions for a set of aqueous solutions. Cantonese, unlike other languages, did not appear to differ greatly from American-English in its general taste descriptive strategy and depth of vocabulary, although Cantonese speakers had a tendency to use 'glutamic' as a descriptive term for monosodium glutamate.
Singleton female mouse fetuses are subsequently unresponsive to the aggression-activating property of testosterone

Eight-day pregnant mice were surgically prepared so that they carried a single fetus which was delivered by cesarean section on Day 18, one day prior to term. Other animals were permitted to carry their entire complement of fetuses which also were delivered surgically. Their position within a uterine horn relative to one another was noted. Adult ovariectomized testosterone-treated females that had been situated in utero contiguous to no male fetuses attacked an olfactory bulbectomized adult stimulus male. In contrast, females that resided singly in the uterus were unresponsive to the hormone; they displayed no aggressive behavior. Masculinization, therefore, appears to occur in utero in the absence of contiguity to male fetuses.
Modeling herding behavior and its risks

Scientific communities can exhibit herding behavior when their members are reluctant to take research risks. This paper examines the epistemic consequences of herding behavior, as well as its surprising robustness. One way that herding behavior can be damped is by incentivizing research risks along the lines of recently announced National Science Foundation initiatives. Our models show that such incentives can have a small, but nevertheless significant impact on a scientific community's epistemic progress.
HYPERTROPHIC OSTEOARTHROPATHY IN CHILDHOOD.

The child who presents with arthritis may have an uncommon complication of a more common underlying disease. Hypertrophic osteoarthropathy, a syndrome characterized by clubbing, periostitis, and arthritis, is always associated in childhood with one of several chronic disease states. Pulmonary disorders have been supplanted by congenital heart disease as the most frequent underlying cause. The salient features of eight cases in children seen at this hospital are presented with a review of the world literature.
Development and evolutionary origin of feathers.

Avian feathers are a complex evolutionary novelty characterized by structural diversity and hierarchical development. Here, I propose a functionally neutral model of the origin and evolutionary diversification of bird feathers based on the hierarchical details of feather development. I propose that feathers originated with the evolution of the first feather follicle—a cylindrical epidermal invagination around the base of a dermal papilla. A transition series of follicle and feather morphologies is hypothesized to have evolved through a series of stages of increasing complexity in follicle structure and follicular developmental mechanisms. Follicular evolution proceeded with the origin of the undifferentiated collar (stage I), barb ridges (stage II), helical displacement of barb ridges, barbule plates, and the new barb locus (stage III), differentiation of pennulae of distal and proximal barbules (stage IV), and diversification of barbule structure and the new barb locus position (stage V). The model predicts that the first feather was an undifferentiated cylinder (stage I), which was followed by a tuft of unbranched barbs (stage II). Subsequently, with the origin of the rachis and barbules, the bipinnate feather evolved (stage III), followed then by the pennaceous feather with a closed vane (stage IV) and other structural diversity (stages Va–f). The model is used to evaluate the developmental plausibility of proposed functional theories of the origin of feathers. Early feathers (stages I, II) could have functioned in communication, defense, thermal insulation, or water repellency. Feathers could not have had an aerodynamic function until after bipinnate, closed pennaceous feathers (stage IV) had evolved. The morphology of the integumental structures of the coelurisaurian theropod dinosaurs Sinosauropteryx and Beipiaosaurus are congruent with the model's predictions of the form of early feathers (stage I or II). Additional research is required to examine whether these fossil integumental structures developed from follicles and are homologous with avian feathers. J. Exp. Zool. (Mol. Dev. Evol.) 285:291–306, 1999.© 1999 Wiley-Liss, Inc.
Ionic Supramolecular Assemblies

Supramolecular structures assembled via noncovalent interactions have found diverse applications in mechanical, biological, electronic, and manufacturing-related fields. Ionic interactions represent key noncovalent interactions, which can be used, for example, to create highly ordered, responsive, conductive, reversible, and/or viscoelastic supramolecular assemblies. The recent advances in the field of ionic supramolecular assemblies, including those prepared from polymers, small molecules, or a combination of the two are reviewed. The versatility and simplicity of constructing ionic supramolecular assemblies are illustrated through several examples. Finally, the outstanding issues and potential opportunities are discussed to stimulate critical discussions and encourage further discovery.
Neonatal Tolerance Revisited: Turning on Newborn T Cells with Dendritic Cells

For some time it has been thought that antigenic challenge in neonatal life is a tolerogenic rather than immunogenic event. Reexamination of the classic neonatal tolerance experiments of Billingham, Brent, and Medawar showed that tolerance is not an intrinsic property of the newborn immune system, but that the nature of the antigen-presenting cell determines whether the outcome is neonatal tolerance or immunization.
Multiple time scale analysis of macrotransport processes

Abstract Convective and diffusive transport of a Brownian tracer corpuscle is analyzed within a multidimensional space decomposed into local (internal) and global (external) subspaces. Multiple time scale methods are employed to successively eliminate from the kinetic equation governing the multidimensional microtransport process its dependence upon each of the internal coordinates. The resulting long-time equation describing the residual global-space macrotransport process derived by this systematic perturbation procedure is shown to accord with the well-established results of generalized Taylor dispersion theory, heretofore obtained by ad hoc arguments. By way of example, this macrotransport description is used to analyze the Taylor dispersion of a solute in a Poiseuille-type solvent flow occuring within a rectangular duct of small, but non-zero, aspect ratio. Elementary dispersion results obtained by ignoring the side walls apply only for relatively short times; for longer times the perturbing presence of the side walls acts to substantially increase the axial dispersivity, even in the limit of zero aspect ratio-where intuition would strongly suggest otherwise.
Gaussian approximation in the theory of MR signal formation in the presence of structure-specific magnetic field inhomogeneities

A detailed theoretical analysis of the free induction decay (FID) and spin echo (SE) MR signal formation in the presence of mesoscopic structure-specific magnetic field inhomogeneities is developed in the framework of the Gaussian phase distribution approximation. The theory takes into account diffusion of nuclear spins in inhomogeneous magnetic fields created by arbitrarily shaped magnetized objects with permeable boundaries. In the short-time limit the FID signal decays quadratically with time and depends on the objects' geometry only through the volume fraction, whereas the SE signal decays as 5/2 power of time with the coefficient depending on both the volume fraction of the magnetized objects and their surface-to-volume ratio. In the motional narrowing regime, the FID and SE signals for objects of finite size decay mono-exponentially; a simple general expression is obtained for the relaxation rate constant deltaR2. In the case of infinitely long cylinders in the motional narrowing regime the theory predicts non-exponential signal decay lnS approximately -tlnt in accordance with previous results. For specific geometries of the objects (spheres and infinitely long cylinders) exact analytical expressions for the FID and SE signals are given. The theory can be applied, for instance, to biological systems where mesoscopic magnetic field inhomogeneities are induced by deoxygenated red blood cells, capillary network, contrast agents, etc.
Investigation of CO Binding and Release from Mo-Nitrogenase during Catalytic Turnover†

During enzymatic turnover in the presence of CO, Mo-nitrogenase has been shown to generate two different EPR signals termed lo-CO (PCO = 0.08 atm) and hi-CO (PCO = 0.5 atm). When the formation of hi-CO is monitored under the conditions of very low electron flux, a 2 min lag is observed prior to the initial detection of the signal followed by a near-linear rate of formation during which the S = 3/2 cofactor signal exhibits similar decay kinetics. Increasing the electron flux produces a significant increase in the rate of both the formation of hi-CO and the decay of the S = 3/2 cofactor. These results are interpreted in terms of a state of the enzyme (redox or structural) generated only during turnover which is needed to initially bind CO to the cofactor. Under high electron flux conditions, new EPR inflections are observed at g = 5.78, 5.15 and g = 1.95, 1.81 and tentatively assigned to S = 3/2 and 1/2 states of the CO-bound cofactor and 1 equiv of oxidized P cluster, respectively. Sudden removal of CO fro...
Scalable solid-state quantum computer based on quantum dot pillar structures

We investigate an optically driven quantum computer based on electric dipole transitions within coupled single-electron quantum dots. Our quantum register consists of a free-standing n-type pillar containing a series of pairwise coupled asymmetric quantum dots, each with a slightly different energy structure, and with grounding leads at the top and bottom of the pillar. Asymmetric quantum wells confine electrons along the pillar axis, and a negatively biased gate wrapped around the center of the pillar allows for electrostatic confinement in the radial direction. We self-consistently solve coupled Schr\"odinger and Poisson equations and develop a design for a three-qubit quantum register. Our results indicate that a single gate electrode can be used to localize a single electron in each of the quantum dots. Adjacent dots are strongly coupled by electric dipole-dipole interactions arising from the dot asymmetry, thus enabling rapid computation rates. The dots are tailored to minimize dephasing due to spontaneous emission and phonon scattering and to maximize the number of computation cycles. The design is scalable to a large number of qubits.
Estimating a binomial parameter with finite memory

This article treats the asymptotic theory of estimating a binomial parameter p with time-invariant finite memory. The approach taken to this problem is as follows. A decision rule is a pair (t,a) in which t fixes the transition function of a finite automaton, and a is a vector of estimates of p . Attention is restricted to automata whose transition functions allow transitions only between adjacent states. Rules (t,a) for which t satisfies this restriction are termed tridiagonal. For the class of prior distributions on [0,1] which have continuous density functions, we study the performance of a corresponding class of tridiagonal rules \{ (t^{\ast},a^{\ast}) \} relative to quadratic loss functions. These rules display sensitivity to the shape of the prior, and have the advantage that the Bayes estimate a^{\ast} (given t^{\ast} ) is easily computed. Within the class of all tridiagonal rules, a particular rule (t^{\ast},a^{\ast}) is shown, for memory size up to 30, to be locally admissible and minimax as well as locally Bayes with respect to the uniform prior.
A Model of Nuclear Organization Demonstrates the Effect of Nuclear Envelope - Chromosome Contacts on 3D Organization of Chromosomes

We describe a method for modeling organization of the interphase nucleus, and its application to polytene chromosomes of Drosophila salivary glands. The model represents chromosomes as polymer chains confined within the nucleus. Physical parameters of the model are taken directly from experiment, no fitting parameters are introduced. The model is used to simulate chromosome tracing experiments. When applied to previously published data 33 new chromosome_nuclear envelope (Chr-NE) contacts are revealed. Most of these new Chr-NE contacts correspond to intercalary heterochromatin - gene poor, dark staining, late replicating regions of the genome; only three correspond to euchromatin - gene rich, light staining, early replicating regions of the genome. Analysis of regions least likely to form Chr-NE contacts reveals that these are mostly euchromatic, but may contain late replication regions or intercalary heterochromatin. We show that Chr-NE contacts may affect long range gene-gene interactions: depending on the chromosome contour length between two contacts, gene-gene interaction probability may increase or decrease. We also develop methods to objectively quantify chromosome territories and intertwining and discuss the corresponding experimental observations.View Large Image | View Hi-Res Image | Download PowerPoint Slide
Purification of α-glycerophosphate dehydrogenase from Drosophila melanogaster

A simple procedure has been devised for the purification of alpha-glycerophosphate dehydrogenase (EC 1.1.1.8) FROM Drosophila melanogaster. The method involves substrate elution of the enzyme from a carboxymethyl cellulose column, followed by salt elution from agarose-hexane-AMP and DEAE columns. The procedure requires only 3 days to complete, results in high yield, and preparations that appear homogeneous by several criteria. A subunit molecular weight of 31 700 was obtained by sodium dodecyl sulphate electrophoresis in 10% acrylamide gels. This value is half that published for the native enzyme, confirming the homodimeric structure of this enzyme suggested by genetic evidence.
Plasmonic enhancing nanoantennas for photodetection

This paper discusses the use of plasmonic nanostructured systems as nanoantennas for photodetection. Even though semiconductors and their heterostructures have many useful properties and widely used in photodetection, their electron density is very small compared to that of metals and, therefore, they have low absorption cross sections. The idea of using metal nanostructured antennas is to combine the high optical responses of metals with the functional electric properties of semiconductors.
MgATP-dependent activation by phosphoenolpyruvate of the E187A mutant of Escherichia coli phosphofructokinase.

Using enzymatic assays and steady-state fluorescence emission, we performed a linkage analysis of the three-ligand interaction of fructose 6-phosphate (Fru-6-P), phosphoenolpyruvate (PEP), and MgATP on E187A mutant Escherichia coli phosphofructokinase (PFK). PEP allosterically inhibits Fru-6-P binding to E. coli PFK. The magnitude of antagonism is 90-fold in the absence and 60-fold in the presence of a saturating concentration of MgATP [Johnson, J. J., and Reinhart, G. D. (1997) Biochemistry 36, 12814-12822]. Substituting an alanine for the glutamate at position 187, located in the allosteric site (i.e., mutant E187A), activates Fru-6-P binding and inhibits the maximal rate of enzyme turnover [Lau, F. T.-K., and Fersht, A. R. (1987) Nature 326, 811-812]. The allosteric action of PEP appears to depend on the presence of the cosubstrate MgATP. In the presence of a saturating concentration of MgATP, PEP enhances the binding of Fru-6-P to the enzyme by a modest 2-fold. Decreasing the concentration of MgATP mitigates the extent of activation. At MgATP concentrations approaching 25 microM, PEP becomes insensitive to the binding of Fru-6-P. At MgATP concentrations < 25 microM, PEP "crosses over" and becomes antagonistic toward substrate binding. The present study examines the role of Glu 187 at the allosteric site in the binding of Fru-6-P and offers a more complex explanation of the mechanism than that described by traditional allosteric mechanistic models.
Beryllium disease: a clinical perspective

A relatively new occupational disease, beryllium poisoning, is discussed. The history of this respiratory disease among workers after beryllium exposure from extraction and alloy manufacturing is not well documented in the US Attempts by industry to delay investigations into beryllium toxicity are described. The specific incidents occurring at a fluorescent lamp manufacturing plant in Salem, Massachusetts are presented. Clinical observations of chronic beryllium disease are discussed. Symptoms are described. The current status of diagnosis and treatment of beryllium poisoning is presented.
Characterization of SyrC, an aminoacyltransferase shuttling threonyl and chlorothreonyl residues in the syringomycin biosynthetic assembly line.

Summary Syringomycin, a lipopeptidolactone assembled from nine amino acid monomers by four enzymes, SyrB1, SyrB2, SyrC, and SyrE, is a cyclic nonribosomal peptide made by plant-associated Pseudomonas spp. This assembly is unusual because the terminal residue, 4-chlorothreonine, has been proposed to be added in trans since the ninth module of the megasynthetase SyrE lacks an adenylation domain required for Thr/Cl-Thr activation. SyrC is now identified as a Thr/Cl-Thr aminoacyltransferase, shuttling the Thr/Cl-Thr moiety between the pantetheinyl arms of the thiolation domain of SyrB1 and the thiolation domain in module nine of SyrE. SyrC uses Cys224 as a catalytic nucleophile to generate a Thr/Cl-Thr- S -enzyme intermediate during transfer. SyrC joins a growing family of such aminoacyl-shuttling enzymes that also use covalent catalysis to move aminoacyl groups from carrier proteins during coumermycin and coronamic acid biosynthesis.
Radiofrequency heating in porcine models with a "large" 32 cm internal diameter, 7 T (296 MHz) head coil.

Radiofrequency (RF) heating of an imaged tissue is a safety concern at ultra-high fields (i.e., static magnetic field strength ≥3 tesla [T]) (1). This is so because more RF power is transferred to an imaged tissue with an increase in the static field strength for a given pulse sequence (2). Additionally, higher conductivity of biological tissues and frequency dependent dielectric losses at higher field strengths cause more RF absorption (3–5). RF power at ultra-high fields is deposited nonuniformly because of the high gyromagnetic ratio of water proton and nonuniform distribution of tissue electrical properties (6,7). Nonuniform RF power together with a nonuniform geometry, tissue distribution, and blood flow may cause nonuniform RF heating with the potential of local hot spots. RF safety guidelines of the International Commission on Non-Ionizing Radiation Protection Committee limit the maximum rise of core body temperature to 0.5 and 1.0°C in normal and controlled operating modes, respectively. The maximum temperature in the head is restricted to 38°C for the two operating modes (i.e., maximum temperature change in the head to 1°C assuming core body temperature of 37°C). The maximum RF power per unit head weight (i.e., the whole head average specific absorption rate, SARavg) is restricted to 3 W kg−1 (averaged over any 6 min), and the maximum local specific absorption rate (SAR) in the head is restricted to 10 W kg−1 (averaged over a 10-g of tissue over any 6 min) for the two operating modes. The SARavg limit over any 10 sec is restricted to three times the SARavg limit of 6 min. No limit exists on the maximum duration of an RF power deposition if the temperature guideline is not exceeded (8,9). MR systems monitor the total RF power transferred from an RF coil alone to assure safety because of the lack of reliable and validated means to predict and monitor subject specific RF heating and local SAR. In principle, RF power, when deposited for a “long” time, may cause in vivo temperature changes greater than 1°C. Thermogenic cellular and systemic hazards are directly related to temperatures and temperature–time history and not to the SARavg and local SAR. The effects of nonuniform brain temperature change in the range of 1–3°C on local and systemic body functions that are not well understood and may cause altered thermophysiologic effects (6,10). Therefore, along with measuring net RF power delivered from an RF coil, it is prudent to study RF heating and associated thermophysiological changes in live, thermophysiologically conservative animal models to humans to better understand human safety at the highest fields. For biomedical human and animal research, 7 T MR systems are used routinely worldwide (11–13). However, only limited 7 T RF heating data are available, which is obtained in a rat with a 7 cm inner diameter quadrature birdcage coil (14). This article presents the first RF heating study because of the RF power deposition with a 7 T human head coil in porcine models of body weight comparable to humans.