cssi/SciSciGPT-SciSciNet huggingface dataset:
Modeling calcium dynamics in neurons with endoplasmic reticulum: existence, uniqueness and an implicit-explicit finite element scheme

Like many other biological processes, calcium dynamics in neurons containing an endoplasmic reticulum are governed by diffusion-reaction equations on interface-separated domains. Interface conditions are typically described by systems of ordinary differential equations that provide fluxes across the interfaces. Using the calcium model as an example of this class of ODE-flux boundary interface problems, we prove the existence, uniqueness and boundedness of the solution by applying comparison theorem, fundamental solution of the parabolic operator and a strategy used in Picard's existence theorem. Then we propose and analyze an efficient implicit-explicit finite element scheme which is implicit for the parabolic operator and explicit for the nonlinear terms. We show that the stability does not depend on the spatial mesh size. Also the optimal convergence rate in $H^1$ norm is obtained. Numerical experiments illustrate the theoretical results.
Translesion polymerase eta both facilitates DNA replication and promotes increased human genetic variation at common fragile sites.

Common fragile sites (CFSs) are difficult-to-replicate genomic regions that form gaps and breaks on metaphase chromosomes under replication stress. They are hotspots for chromosomal instability in cancer. Repetitive sequences located at CFS loci are inefficiently copied by replicative DNA polymerase (Pol) delta. However, translesion synthesis Pol eta has been shown to efficiently polymerize CFS-associated repetitive sequences in vitro and facilitate CFS stability by a mechanism that is not fully understood. Here, by locus-specific, single-molecule replication analysis, we identified a crucial role for Pol eta (encoded by the gene POLH) in the in vivo replication of CFSs, even without exogenous stress. We find that Pol eta deficiency induces replication pausing, increases initiation events, and alters the direction of replication-fork progression at CFS-FRA16D in both lymphoblasts and fibroblasts. Furthermore, certain replication pause sites at CFS-FRA16D were associated with the presence of non-B DNA-forming motifs, implying that non-B DNA structures could increase replication hindrance in the absence of Pol eta. Further, in Pol eta-deficient fibroblasts, there was an increase in fork pausing at fibroblast-specific CFSs. Importantly, while not all pause sites were associated with non-B DNA structures, they were embedded within regions of increased genetic variation in the healthy human population, with mutational spectra consistent with Pol eta activity. From these findings, we propose that Pol eta replicating through CFSs may result in genetic variations found in the human population at these sites.
The Middle East in Modern World History

The Middle East in Modern World History examines how global trends over the last 200 years have shaped the Middle East and how these trends were affected by the region’s development. Covering a key period in the history of the Middle East, this book highlights three major trends within the region’s development over the past two centuries: the role of the region as a strategic conduit between East and West, the development of the region’s natural resources, especially oil, and the impact of a rapidly globalizing world economy on the Middle East. This new edition extends coverage to the present day and includes more thematic and interpretive discussion on the impact of global migration and the evolution of the roles of women. It also provides more theoretical insights into current historical research and recent developments in the region, firmly placing these developments within their historical context. Clearly written and supported throughout by maps, images, discussion questions, and suggestions for further reading, as well as including a comprehensive chronology and glossary that enable readers to develop a clearer picture of political, economic, social, and cultural life within the region, The Middle East in Modern World History is the perfect textbook for all students of the history of the modern Middle East within a global context.
Influence of Chromosome Structure on the Frequency of tonB trp Deletions in Escherichia coli

The frequency of tonB trp deletions varies in different strains and substrains of Escherichia coli. Studies with chromosomal hybrids constructed by transducing various segments of the cysB-trp-suIII region from K-12(Ymel) into K-12(W3110) indicate that the characteristic low deletion frequency of K-12(Ymel) is determined largely by the (genetic) structure of the trp-suIII region of the chromosome. Transduction of the trp region from K-12(W3110) or K-12(Ymel) into strain B has little effect on the frequency of tonB trp deletions in that strain. When tonB trp deletions occur at 42 C rather than at 37 C, there is a significant reduction in the frequency of deletions in all strains examined except K-12(Ymel) and hybrids exhibiting a Ymel deletion pattern. The magnitude of this temperature effect in different K-12 strains increases proportionally with the frequency of tonB trp deletions at 37 C. At 42 C the frequency of tonB trp deletions in all K-12 strains approaches the low frequency observed for Ymel at 37 or 42 C. In contrast, spontaneous deletions in another region of the genome which simultaneously result in resistance to phages T7 and lambda and in proline auxotrophy (tfrA pro deletions) occur at a constant frequency regardless of growth temperature or the structure of the chromosome in the trp region. Two mutants of strain KB30 obtained after treatment with nitrosoguanidine show very low tonB trp deletion frequencies. The alterations in both mutants map in the trp region of the chromosome. These studies indicate that the structure of the cysB-trp-suIII region is responsible for many of the characteristic deletion frequencies observed.
The impact of missing data on data mining

Data mining is based upon searching the concatenation of multiple databases that usually contain some amount of missing data along with a variable percentage of inaccurate data, pollution, outliers, and noise. The actual data-mining process deals significantly with prediction, estimation, classification, pattern recognition, and the development of association rules. Therefore, the significance of the analysis depends heavily on the accuracy of the database and on the chosen sample data to be used for model training and testing. The issue of missing data must be addressed since ignoring this problem can introduce bias into the models being evaluated and lead to inaccurate data mining conclusions.
The lesions of porcine adenoviral infection in germfree and pathogen-free pigs.

A porcine adenovirus isolated from the brain of a pig with encephalitis was shown to be pathogenic for germfree and pathogen-free pigs. Lesions were produced by 5 different routes of inoculation, of which the intranasal was the most effective. The animals inoculated intranasally developed an interstitial pneumonia which involved entire lobules and was especially prominent near the hilus. Distinct intranuclear inclusion bodies were seen. Lesions and inclusion bodies were also found in the kidneys, thyroids, and lymph nodes. Viral antigen was demonstrated in the lesions by immunofluorescence. Intracerebral inoculation resulted in polioencephalitis involving only the cerebral cortex. Many features of this disease were similar to adenoviral diseases of man and other animal species.
Calcium/calmodulin-activated phosphodiesterase expressed in olfactory receptor neurons

We show that calmodulin-dependent phosphodiesterase (CAM-PDE) is selectively expressed in mature olfactory receptor neurons within the olfactory mucosa. Immunocytochemical staining reveals neuronal immunoreactivity that is most pronounced within cilia, dendritic knobs, and axon bundles. Neither sustentacular cells nor basal cells display immunoreactivity. The extent of loss of neuronal immunoreactivity following bulbectomy resembles loss of the neuronal population. High- affinity CAM-PDE activity in olfactory cilia is fivefold greater than in brain, when assayed at low micromolar cAMP. This activity is depleted in turbinates following bulbectomy. Olfactory mucosal PDE activity is composed of a minimum of two major forms. In the absence of Ca(2+), rolipram-sensitive PDE comprises 65% of total activity. Following stimulation by Ca2+, CAM-PDE activity is elevated sixfold to become the predominant form, thereby increasing total activity 300%, with half-maximal effect at 1 microM Ca2+. We propose that Ca2+ stimulation of CAM-PDE may be necessary for termination of olfactory signals.
Turbulence Characteristics in the Annulus-Wall Boundary Layer and Wake Mixing Region of a Compressor Rotor Exit

The flow at the exit of a turbomachinery rotor near the annulus wall is three-dimensional with a varying degree of turbulence and nonisotropic characteristics. The characteristics of the turbulence vary considerably with radial and axial location, blade loading, Reynolds number, free-stream turbulence, and the rotor blade geometry. This paper is concerned with the turbulence properties near the annulus wall region of a moderately loaded compressor blade. The variation of the streamwise, normal, and radial intensities as well as the stresses across the wake, its profile and decay characteristics, were determined with a tri-axial hot-wire probe in the stationary frame of reference. The turbulence characteristics in the annulus-wall region of the rotor exit were found to be highly complex due to the interaction of the blade wake and the annulus wall.
Analytical techniques and bioactivity assays to compare the structure and function of filgrastim (granulocyte-colony stimulating factor) therapeutics from different manufacturers

The FDA has approved more than 100 protein and peptide drugs with hundreds more in the pipeline (Lanthier et al. in Nat Rev Drug Discov 7(9):733–737, 2008). Many of these originator biologic products are now coming off patent and are being manufactured by alternate methods than the innovator as follow-on drugs. Because changes to the production method often lead to subtle differences (e.g., degradation products, different posttranslational modifications or impurities) in the therapeutic (Schiestl et al. in Nat Biotechnol 29(4):310–312, 2011), there is a critical need to define techniques to test and insure the quality of these drugs. In addition, the emergence of protein therapeutics manufactured by unapproved methodologies presents an ongoing and growing regulatory challenge. In this work, high-resolution mass spectrometry was used to determine the presence or absence of posttranslational modifications for one FDA-approved and three foreign-sourced, unapproved filgrastim products. Circular dichroism (CD) was used to compare the secondary structure and probe the temperature stability of these products. Native 2D 1H,15N-heteronuclear singular quantum coherence (HSQC) NMR test was applied to these samples to compare the higher-order structure of the four products. Finally, a cell proliferation assay was performed on the filgrastims to compare their bioactivity, and stressed filgrastim was tested in the bioassay to better understand the effects of changes in protein structure on activity. The results showed that orthogonal approaches are capable of characterizing the physiochemical properties of this protein drug and assessing the impact of structural changes on filgrastim purity and potency.
Global Child Health Fellowship Programs in Demand: In Reply

We are excited about the prospect of multiple pediatric global health fellowships. Given the desperate state of child health worldwide and the growing interest in professional development for pediatric global health leaders, there is a clear need for formal postresidency training in pediatric …
Heritability of psychosis in Alzheimer disease.

Objective The authors have previously demonstrated familial clustering of psychotic symptoms in late-onset Alzheimer disease (LOAD+P) and sought to estimate and explore the nature of the heritability of LOAD+P. Methods The heritability of LOAD+P, defined by single and multiple psychotic symptoms, was estimated with data from the National Institute of Mental Health AD Genetics Initiative. Results The estimated heritability for LOAD+P defined by multiple psychotic symptoms was 61%; for LOAD+P defined by any occurrence of psychotic symptoms, it was 30%. Conclusion Multiplicity of symptoms may represent a useful means for defining a genetically determined LOAD+P phenotype.
Factors associated with colon cancer screening: the role of patient factors and physician counseling.

Abstract Background. The prevalence of colon cancer screening is nationally low. The relative contribution of patient factors and physician counseling patterns to the low prevalence of screening is unclear. Methods. We used multivariable analysis to examine the prevalence of colon cancer screening nationally and the reasons for this low prevalence using data from the 2000 National Health Interview Survey, a nationally generalizable survey of US households. Results. Among 11,427 respondents to the Cancer Control Supplement, 16% reported annual fecal occult blood testing (FOBT) and 29% reported having undergone a sigmoidoscopy in the last 5 years or a colonoscopy in the last 10 years. After adjusting for age, sex, body mass index (BMI), healthcare access, and region of the country, Hispanics were less likely to undergo FOBT [OR 0.7 (95% CI 0.6–0.9)] and sigmoidoscopy or colonoscopy [OR 0.8 (95% CI 0.7–0.9)] compared to Whites. Respondents with lower education levels were also less likely to undergo screening. These factors were not associated with being less adherent to physician recommendations for screening. Nevertheless, non-Whites and those less educated were less likely to receive counseling from their health provider about colon cancer screening. Among respondents who did not undergo FOBT, 64% were unaware they needed the test; only 2% cited pain and discomfort as a deterrent, but 94% were not counseled by their physician about the test. Among those who did not undergo sigmoidoscopy or colonoscopy, 72% were unaware that they needed the test and only 1% was deterred by pain and discomfort; 92% were not counseled by their physician. Conclusion. The low prevalence of screening for colorectal cancer appears to be due to lack of awareness and inadequate provider counseling rather than poor patient acceptance for screening. Systematic counseling about colorectal cancer screening will likely improve screening rates and reduce disparities by race/ethnicity and education.
Moments of Gaps Between k-Free Numbers

Abstract Let k be a fixed positive integer, and let s n denote the n th k -free number. If k ≥ 3 and 0 ≤ γ k − 2 + 4/( k + 1), then [formula].
Coagulation disorders and liver disease.

Hepatic disease is associated with abnormalities of coagulation factor production, which can cause abnormalities of certain screening tests, such as the prothrombin time and activated partial thromboplastin time. Clinically evident bleeding is unusual, however, except in cases of advanced liver disease or acute, diffuse hepatic injury. This article presents an overview of the subclinical coagulopathies seen in domestic animals and man with both acute and chronic liver disease.
Wee1-dependent mechanisms required for coordination of cell growth and cell division

Wee1-related kinases function in a highly conserved mechanism that controls the timing of entry into mitosis. Loss of Wee1 function causes fission yeast and budding yeast cells to enter mitosis before sufficient growth has occurred, leading to formation of daughter cells that are smaller than normal. Early work in fission yeast suggested that Wee1 is part of a cell-size checkpoint that prevents entry into mitosis before cells have reached a critical size. Recent experiments in fission yeast and budding yeast have provided new support for this idea. In addition, studies in budding yeast have revealed the existence of highly intricate signaling networks that are required for regulation of Swe1, the budding yeast homolog of Wee1. Further understanding of these signaling networks may provide important clues to how cell growth and cell division are coordinated.
Carbon dioxide pneumoperitoneum-mediated attenuation of the inflammatory response is independent of systemic acidosis.

Background The purpose of this study was to determine if systemic acidosis induced by peritoneal absorption of carbon dioxide (CO2) during laparoscopy plays a role in CO2 pneumoperitoneum–mediated attenuation of the acute phase inflammatory response associated with perioperative sepsis. The influence of hepatic polymorphonuclear (PMN) leukocyte infiltration on this phenomenon was also investigated. Methods Forty-five rats were randomized into 5 groups: anesthesia control, open cecal ligation and puncture (OCLP), laparoscopic cecal ligation and puncture using helium for insufflation (He LCLP), LCLP using CO2 with continued spontaneous ventilation (LCLP-SV), and LCLP using CO2 with intubation and positive pressure ventilation (LCLP-PPV). Results After 30 minutes, arterial blood gas parameters remained normal in control, OCLP rats, and He LCLP rats, while CO2 LCLP-SV rats developed significant hypercarbic acidosis. This acidosis was corrected in CO2 LCLP-PPV rats (P Conclusions CO2 insufflation–induced systemic acidosis is not responsible for the reduction in the acute phase inflammatory response observed in laparoscopic animal models of sepsis. Hepatic PMN infiltration also does not appear to mediate this effect.
The Relationship of Post-traumatic Stress Disorder and Depression to Antiretroviral Medication Adherence in Persons with HIV

ABSTRACT In HIV/AIDS, symptoms of depression or post-traumatic stress may interfere with important self-care behaviors such as the ability to adhere to one's medical treatment regimen. However, these problems may frequently go undetected in HIV care settings. The present study used brief self-report screening measures of depression and post-traumatic stress disorder (PTSD) in the HIV/AIDS care settings to examine (1) frequency of positive screens for these diagnoses; (2) the degree to which those with a positive screen were prescribed antidepressant treatment; and (3) the association of continuous PTSD and depression symptom scores, and categorical (screening positive or negative) PTSD and depression screening status, to each other and to ART adherence as assessed by the Medication Event Monitoring System, regardless of antidepressant treatment. Participants were 164 HIV-infected individuals who took part in a multisite adherence intervention study in HIV treatment settings in Massachusetts. Available dat...
Conjugated donor-acceptor copolymer semiconductors with large intramolecular charge transfer : Synthesis, optical properties, electrochemistry, and field effect carrier mobility of thienopyrazine-based copolymers

Several conjugated thieno[3,4-b]pyrazine-based donor−acceptor copolymers were synthesized by Stille and Suzuki copolymerizations, and their optical, electrochemical, and field-effect charge transport properties were characterized. The new copolymers, poly(5,7-bis(3-dodecylthiophen-2-yl)thieno[3,4-b]pyrazine) (BTTP), poly(5,7-bis(3-dodecylthiophen-2-yl)thieno[3,4-b]pyrazine-alt-2,5-thiophene) (BTTP-T), poly(5,7-bis(3-dodecylthiophen-2-yl)thieno[3,4-b]pyrazine-alt-9,9-dioctyl-2,7-fluorene) (BTTP-F), and poly(5,7-bis(3-dodecylthiophen-2-yl)thieno[3,4-b]pyrazine-alt-1,4-bis(decyloxy)phenylene) (BTTP-P), had moderate to high molecular weights, broad optical absorption bands that extend into the near-infrared region with absorption maxima at 667−810 nm, and small optical band gaps (1.1−1.6 eV). They showed ambipolar redox properties with low ionization potentials (HOMO levels) of 4.6−5.04 eV. The field-effect mobility of holes varied from 4.2 × 10-4 cm2/(V s) in BTTP-T to 1.6 × 10-3 cm2/(V s) in BTTP-F. These r...
Experimental component mode synthesis of structures with sloppy joints

The accuracy of component mode synthesis is investigated experimentally for substructures coupled by nonideal joints. The work is based upon a segmented experimental beam for which free-interface frequency response matrices are measured for each segment. These measurements are used directly in component mode synthesis to predict the behavior of the assembled structure; the segments are then physically joined, and the resulting frequency response of the superstructure is compared to the prediction. Rotational freeplay is then introduced into the connecting joint, and the new superstructure frequency response is compared to the original linear component mode synthesis prediction. The level of accuracy to be expected in component mode synthesis is discussed in terms of the degree of nonlinearity in the joints, mode number, and mode shapes.
Benign metastasizing pleomorphic adenoma of salivary gland: Diagnosis of bone lesions by fine‐needle aspiration biopsy

Two cases of benign salivary gland pleomorphic adenomas metastatic to bone (benign-metastasizing pleomorphic adenomas) diagnosed by fine-needle aspiration biopsy are presented. Both primary tumors were slightly atypical cytologically but neither case demonstrated features of carcinoma. The metastatic lesions contained benign epithelial, myoepithelial, and stromal components. In both cases the clinical history was either not known by the radiologist or not communicated to the cytopathologist interpreting the case, and a primary tumor of bone was the leading clinical diagnosis. Obtaining pertinent clinical history and comparing the cytomorphology of the bone aspirate with the primary parotid tumor allowed for an accurate diagnosis in both cases. The differential diagnosis with primary bone tumors is discussed and the importance of clinical history is emphasized.
Level structure of the odd-odd nucleus 22489Ac

Abstract The level structure of the odd-odd nucleus 224Ac has been studied by measuring radiations associated with the α-decay of the 22 h 228Pa isotope. The 228Pa activity was produced by the irradiation of Th metal foils with 45 MeV protons. The Pa fraction was subsequently chemically isolated. Alpha singles as well as αγ-, αe-, αγγ-coincidence measurements were performed with thin sources, and a partial level scheme was deduced for the 224Ac. Although the spins of the observed levels have not been uniquely determined, the data establish positive- and negative-parity bands which exhibit characteristics of parity doublets. In particular, two bands at 354 and 360 keV appear to be members of a parity doublet. The similarity in the hindrance factors of α-decays to the 354 and 360 keV levels, which have opposite parities, indicates that the wavefunctions of the two states are very similar, which is a signature for octupole deformation.
A Review of Quantitative Phase-Field Crystal Modeling of Solid–Liquid Structures

Phase-field crystal (PFC) is a model with atomistic-scale details acting on diffusive time scales. PFC uses the density field as its order parameter, which takes a constant value in the liquid phase and a periodic function in the solid phase. PFC naturally takes into account elasticity, solid–liquid interface free energy, surface anisotropy, and grain boundary free energy by using this single-order parameter in modeling of coexisting solid–liquid structures. In this article, the recent advancements in PFC modeling of materials nanostructures are reviewed, which includes an overview of different PFC models and their applications, and the numerical algorithms developed for solving the PFC governing equations. A special focus is given to PFC models that simulate coexisting solid–liquid structures. The quantitative PFC models for solid–liquid structures are reviewed, and the methods for determining PFC model parameters for specific materials are described in detail. The accuracy of different PFC models in calculating the solid–liquid interface properties is discussed.
Full-scale structural model of the Inferior Olive and Olivocerebellar projection constructed from constraining meshes and directed growth

Constructing a full scale model of a brain structure demands several considerations. First, to be useful, the model must be of a computable size. Previously, we mapped the computation of dense multicompartmental models of neural tissue to the Blue Gene/P supercomputer at ~250 neurons per node of this machine. A ~30k neuron structure such as the Inferior Olive [1] is therefore well within the limits of today's machines, and so we aimed to build a structural model of this structure that could appropriately constrain a hypothetical physiological model. Next, to constrain olivary physiology appropriately with our structural model, we included axons in addition to the usual structural constraints on neuronal integration imposed by dendritic morphologies, because spike generation and bursting properties of olivary neurons depend on axonal length [2]. To create our structural model, we first constructed a 3-D mesh from a segmented stack of slices through the granule cell and Purkinje cell layers of the rat cerebellum. Through this mesh, we required olivocerebellar projections and climbing fibers to course (Figure 1A, 1B) to arrive at and create Purkinje cell ramifications [3]. This method generates our distribution of axon lengths. Figure 1 A. Bounding triangular meshes for cerebellar granule cell layer (top) and inferior olivary nucleus (bottom), embedded in brain coordinates. B. Granule cell layer mesh constrains waypoint-based axonal growth into the Purkinje cell layer of olivary neurons, ... Finally, we constrained dendritic morphology using a version of our previous model of self-referentially biased dendritic growth [4], modified to give a better match to olivary neuron morphology. This new model takes as input a 3-D mesh, which approximates nucleus boundaries using measurements of the Inferior Olive size and composition [1]. As before, we generated dendritic arbors to match morphological measures [5], but determined that their characteristic spiral shape depends on a repulsive force from the bounding mesh. The full 24,815 dendritic arbors were then generated on 64 nodes of Blue Gene/Q, running 8 tasks/node, and 8 threads/task in <15 mins. (Figure ​(Figure1C).1C). We discuss future physiological models, including gap junctions, constrained by this structural model.
Frost rings in trees as records of major volcanic eruptions

New data about climatically-effective volcanic eruptions during the past several thousand years may be contained in frost-damage zones in the annual rings of trees. There is good agreement in the timing of frost events and recent eruptions, and the damage can be plausibly linked to climatic effects of stratospheric aerosol veils on hemispheric and global scales. The cataclysmic proto-historic eruption of Santorini (Thera), in the Aegean, is tentatively dated to 1628–26 BC from frost-ring evidence.
Automatic Object Detection And Recognition Using Simple Geometric Primitives.

The template matching method has been more successful in character symbols recognition than in object recognition. The major disadvantage in the later type of problems is that the number of templates that needs to be stored increases with the number of different objects to be recognized. The relatively small and fixed number of basic symbols used in writing any word in a given language is what makes template matching the most widely used method in problems related to the recognition of handwritten or printed character symbols.
Missed eWOM opportunities: A cross-sector analysis of online monitoring behavior

This paper provides empirical evidence that major sectors of the USA are not listening to pertinent online conversations (electronic word-of-mouth [eWOM]) that occur outside of their own social media portals. Data include cross sector as well as longitudinal research on prominent sectors, including business, not for profits, and academia. The Inc. 500 (fastest-growing US companies), top charities, and colleges and universities all neglect, to some extent, the monitoring of eWOM. Findings indicate that monitoring behavior may be related to how involved an organization is in social media, if they have a written policy governing its use within the organization, if they have specific goals that are related to their social media plan, if they use tracking measures such as page views, numbers of fans or followers, and how they staff the social media function. Charities are most likely to engage in monitoring behavior for their causes. The academic sector often employs part-time (student) assistance with its soc...
Slow Passage Through the Nonhyperbolic Homoclinic Orbit of the Saddle‐Center Hamiltonian Bifurcation

Slowly varying Hamiltonian systems, for which action is a well-known adiabatic invariant, are considered in the case where the system undergoes a saddle center bifurcation. We analyze the situation in which the solution slowly passes through the nonhyperbolic homoclinic orbit created at the saddle-center bifurcation. The solution near this homoclinic orbit consists of a large sequence of homoclinic orbits surrounded by near approaches to the autonomous nonlinear nonhyperbolic saddle point. By matching this solution to the strongly nonlinear oscillations obtained by averaging before and after crossing the homoclinic orbit, we determine the change in the action. If one orbit comes sufficiently close to the nonlinear saddle point, then that one saddle approach instead satisfies the nonautonomous first Painleve equation, whose stable manifold of the unstable saddle (created in the saddle-center bifurcation) separates solutions approaching the stable center from those involving sequences of nearly homoclinic orbits.
Cathodoluminescence spectroscopy of free and bound excitons in chemical-vapor-deposited diamond.

Cathodoluminescence (CL) spectroscopy was used to study exciton recombination at temperatures from 80 to 280 K in undoped and boron-doped diamond particles grown by hot-filament chemical vapor deposition. Spectral lines due to free and bound excitons were observed in the near-band-gap region, 4.6--5.5 eV. (The band gap of diamond is at 5.49 eV.) In the undoped particles, free-exciton lines were observed at 5.27 and 5.12 eV. Another set of lines, not previously reported, was observed between 4.7 and 5.0 eV, with the most intense lines at 4.757, 4.832, and 4.950 eV. The latter set of lines is attributed to excitons bound to lattice defects, possibly dislocations. In the boron-doped particles, excitons bound to boron acceptors were found to dominate the near-band-gap CL spectrum at low temperature. The most intense acceptor-bound-exciton line is at 5.20 eV. In both boron-doped and undoped particles, the exciton lines were much less intense in {111} crystal-growth sectors than in {100} sectors. Quenching of the exciton luminescence due to nonradiative recombination is believed to be the cause of the reduced intensity in the {111} sectors. The temperature dependence of the intensities, peak positions, and peak widths of the exciton lines was examined. The free and acceptor-bound excitons in the boron-doped particles were found to be in thermal equilibrium with each other. In the undoped particles, the free and defect-bound excitons were not in thermal equilibrium; the higher-energy bound-exciton lines (at 4.832 and 4.950 eV) decreased more rapidly with increasing temperature than either the lowest-energy bound-exciton line (at 4.757 eV) or the free-exciton lines.This behavior is attributed to thermally activated transitions from the higher-energy bound-exciton states to the lowest-energy state. The full width at half maximum (FWHM) of the free-exciton line, ${\mathit{W}}_{\mathrm{FE}}$, increased with temperature at about the rate predicted for excitations thermalized near the bottom of a parabolic energy band: ${\mathit{W}}_{\mathrm{FE}}$(T)=${\mathit{W}}_{\mathrm{FE}}$(0)+1.795kT. The FWHM's of the defect-bound- and acceptor-bound-exciton lines also increased with temperature, but at slower rates than for the free exciton. The peak positions of the exciton lines increased slightly with increasing temperature.
Derotation of the cosmic microwave background polarization: Full-sky formalism

Mechanisms have been proposed that might rotate the linear polarization of the cosmic microwave background (CMB) as it propagates from the surface of last scatter. In the simplest scenario, the rotation will be uniform across the sky, but the rotation angle may also vary across the sky. We develop in detail the complete set of full-sky quadratic estimators for the rotation of the CMB polarization that can be constructed from the CMB temperature and polarization. We derive the variance with which these estimators can be measured and show that these variances reduce to the simpler flat-sky expressions in the appropriate limit. We evaluate the variances numerically. While the flat-sky formalism may be suitable if the rotation angle arises as a realization of a random field, the full-sky formalism will be required to search for rotations that vary slowly across the sky as well as for models in which the angular power spectrum for the rotation angle peaks at large angles.
Calcium-mediated Stress Kinase Activation by DMP1 Promotes Osteoblast Differentiation

Calcium signaling and calcium transport play a key role during osteoblast differentiation and bone formation. Here, we demonstrate that DMP1 mediated calcium signaling, and its downstream effectors play an essential role in the differentiation of preosteoblasts to fully functional osteoblasts. DMP1, a key regulatory bone matrix protein, can be endocytosed by preosteoblasts, triggering a rise in cytosolic levels of calcium that initiates a series of downstream events leading to cellular stress. These events include release of store-operated calcium that facilitates the activation of stress-induced p38 MAPK leading to osteoblast differentiation. However, chelation of intracellular calcium and inhibition of the p38 signaling pathway by specific pharmacological inhibitors and dominant negative plasmid suppressed this activation. Interestingly, activated p38 MAPK can translocate to the nucleus to phosphorylate transcription factors that coordinate the expression of downstream target genes such as Runx 2, a key modulator of osteoblast differentiation. These studies suggest a novel paradigm by which DMP1-mediated release of intracellular calcium activates p38 MAPK signaling cascade to regulate gene expression and osteoblast differentiation.
The Chicago Classification of esophageal motility disorders, v3.0.

Esophageal high-resolution manometry with esophageal pressure topography (EPT) is now the gold standard to assess esophageal motility disorders. The Chicago Classification categorizes esophageal motility in EPT based on the analysis of ten test swallows conducted in a supine posture. An algorithm is then applied which classifies motility hierarchically as achalasia, motility disorders never observed in controls (absent peristalsis, distal esophageal spasm, jackhammer esophagus) and peristaltic abnormalities statistically different than normal (frequent failed, weak, rapid, and hypertensive peristalsis). Whereas the first categories are invariably associated with esophageal symptoms, the clinical relevance of the latter category remains to be fully defined. Going forward, future investigations will focus on the classification of esophageal motility disorders after esophagogastric surgery, on the evaluation of esophagogastric junction in a context of gastroesophageal reflux disease and on UES function.
RECURRENCE OF AN ODONTOGENIC KERATOCYST IN A BONE GRAFT

The recurrence of an odontogenic keratocyst in a bone graft after partial mandibulectomy and reconstruction is presented. The possible reasons for recurrence are discussed, and methods of treatment reviewed.
Mechanisms of noise damage to the cochlea

The review will first outline the history, pathology and pathophysiology of noise-induced hearing loss and then focus on biochemical and molecular mechanisms of hair cell damage. Calcium influx into sensory cells and generation of reactive oxygen species are initial events leading to an imbalance in the redox homeostasis of the cell and the activation of cell death pathways. Vasoconstriction as well as excitotoxic reactions at the inner hair cell synapse may contribute to the overall manifestations of noise trauma. Individual steps in this sequence leading to apoptotic or necrotic cell death will be discussed based on molecular evidence and on pharmacological manipulation of noise-induced signaling pathways.
Ultradrawing of polystyrene by solid‐state coextrusion: Shear‐induced crystallization in isotactic polystyrene

Polystyrene with a 60% isotactic dyad content (iPS) was subjected to two-stage solid-state coextrusion at 124 and 160°C. It was shown that only shear-induced crystallization occurred with the amount of crystallinity strongly dependent on draw ratio. The steep increase in crystallinity from 0 to 29% is accompanied by a marked increase in the absolute total birefringence from 0 to 30 × 10−3 and the tensile properties, from 2.5 GPa to 4.5 GPa, giving strong evidence for the necessity of a crystalline phase to achieve higher tensile moduli. Wide-angle X-ray scattering showed a higher crystal orientation for the extrudate produced at 124°C than for the one produced at 160°C. Thermal shrinkage experiments support a partial dissipation of orientation after extrusion at 160°C and on reextrusion in general. Electron microscopy revealed a fibrous nature for the solid-state coextrudates produced at both temperatures.
Epicardial activation of the human ventricle: effects of left ventricular hypertrophy.

To determine the effects of left ventricular hypertrophy on eplcardlal activation of the human heart, Intraoperative eplcardlal mapping of 40 to 66 points was performed In 10 patients undergoing aortic valve replacement. Mean calculated left ventricular mass was 364 ± 98 g. All patients had normal left ventricular contraction. Earliest eplcardlal activation occurred In the anterior right ventricle In all patients. In 9 patients, it was the only eplcardlal breakthrough point. One patient had a single Inferior left ventricular breakthrough point. Eplcardlal activation spread from the right ventricle towards the left ventricle in both the anterior and inferior direction. Latest eplcardlal activation occurred at the base of the left ventricle In 9 patients and the base of the right ventricle In 1. When compared with patients with coronary artery disease, normal ventricular contraction, and no left ventricular hypertrophy, patients with hypertrophy had fewer left ventricular breakthrough points (p <0.001) and were more likely to have latest activation at the left ventricular base (p <0.001). We conclude that left ventricular hypertrophy Is associated with marked changes In the pattern of epicardlal activation. These changes may reflect delay In spread from endocardium due to the increased wall thickness.
On sequencing problems of repetitive production systems

The two-machine sequencing problem for a repetitive production system that is viewed as a deterministic discrete-event dynamic system is considered. The objective is to minimize the steady period, which is also the average weight of the critical circuit of the timed marked graph describing the system. The classification of the sequencing problems is done according to the ordering ranks of the ordering matrices. The two-machine sequencing problem is completely solved. The discussion is based on the theories of time-marked graphs and max algebra. >
Potential of a beryllium x-ray lens

The use of refractive lenses for focusing x-ray beams has been the subject of publications since the early 1980s. Detailed calculations have been made for different shapes for the refractive lens: cylindrical, spherical, parabolic, and for a Fresnel-type refractive lens. The main drawback to the use of a single refractive lens to focus x-rays is that the index of refraction (n equals 1 - (delta) ) is very close to 1, which results in a lens with a very long focal length. Recently Snigerov and others have suggested and experimentally demonstrated, using cylindrical-shaped lenses, that this problem of long focal lengths can be overcome by using many lenses in series. Each lens refracts the photon through a small angle, but the sum of these sequential changes in direction can be moderately large. This increase in effective refraction angle reduces the focal length of the lens to a few meters or less and makes the multi-element lens a much more useful instrument for focusing x-rays. This paper, annualizes the expected performance of a lens consisting of a series of aligned hollow spheres in a beryllium substrate. The use of hollow spheres rather than hollow cylinders produces focusing of the x rays into a small focal spot in contrast to the single-directional focusing of the hollow cylinders, which produces a line focus. The use of beryllium as the substrate results in lower photo cross sections for both scattering and absorption relative to the value of the refractive index as compared to higher-Z materials and results in higher transmission values than for lenses with thin webs between the lens elements without distorting the surfaces of the neighbor lens element. This plus beryllium's low density, keep the absorption and scattering in the web at a minimum. The calculations suggest that one will be able to make Be lenses with short focal lengths (1 to 2 m) with useable transmissions (10 to 30%). Two multi-element lenses have been constructed: one with 20 1-mm-diameter hollow spheres in an aluminum substrate, and one with 50 hollow spheres, 1 mm in diameter, in a beryllium substrate. Some construction details and calculations of the expected performance, are given for these two multi-element lenses.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Perioperative Management of Sickle Cell Disease Children Undergoing Adenotonsillectomy

OBJECTIVE: To determine if outpatient tailored perioperative management has the same complication rate as that previously published for sickle cell disease (SCD) children who undergo adenotonsillectomy.STUDY DESIGN AND SETTING: Retrospective chart review of SCD children who underwent tonsillectomy with outcome measures of perioperative management and postsurgical complications.RESULTS: Of 41 patients, 61% were monitored for <24 hours with the average length of stay being 2 days (range, 1 to 10). Postoperative complications were noted in 9 (22%) patients, including 8 (20%) with hypoxia, 4 (10%) fever, 3 (8%) acute chest syndrome, and 1 (2.4%) airway fire, which are similar to the published literature.CONCLUSIONS: Current literature supports extensive perioperative management with hospital stays averaging 3 to 5 days. These data demonstrate that the majority of these patients can be managed with <24-hour hospitalization stays with similar complication rates as previously described in the literature.SIGNIFIC...
Models for breakdown-resistant dielectric and ferroelectric ceramics

Abstract Models for dielectric breakdown are proposed and analysed, with emphasis on concepts leading to breakdown-resistant materials. The Griffith energy balance is extended to cracks under combined electrical and mechanical loading, and to conductive tubular channels. Breakdown strength for a perfect crystal is estimated by an analogue of the Frenkel model. In a crystal subjected to an electric field the equilibrium displacement of the electron clouds is described by a curve with periodicity of the lattice constant. A theory of breakdown-resistant laminates is proposed on the basis of charge relocation, facilitated by breakdown of the weak layers and the interfaces. A process by which a conducting path grows like a crack in ferroelectric ceramics is discussed, followed by an outline of fields around conducting cracks in piezoelectric ceramics.
Group Rehabilitation for the Vascular-Disease Amputee

Group therapy for lower-extremity, vascular-disease amputees was successful in the return of these patients to their normal milieu. Thirty men (mean age, 63 years) were studied during a one-year period. The group meetings progressed from a phase of directed therapy to one of nondirected therapy. This group of hospitalized amputees was chosen specifically because of its social, economic and medical identity. After a self-identified adequate period of therapy, all patients returned to their former places in society.
High Frequency Pulse Propagation in Nonlinear Dielectric Materials

Abstract We consider a variational formulation based on Maxwell's equations for the propagation of high-frequency (gigahertz to terahertz) ultrashort input pulses in dielectric materials modeled by a linear Debye medium. We demonstrate computationally the emergence of Brillouin precursors in the material (water) and the fact that the peak of this transient is attenuated at a much slower rate than is the carrier frequency. In the 0.1– 1 THz regime the carrier frequency does not propagate in our calculations. Only the precursors enter the material, and this is in line with experiments reported by Pleshko and Palocz (Phys. Rev. Lett. 22 (1969) 1201). We also implement models that include nonlinearly forced Debye and nonlinear Debye polarization dynamics and demonstrate the importance of nonlinear effects, especially when the amplitude of the input signal is large. This is an important step in understanding high-frequency pulse propagation, and it has potential applications in the assessment of safety standards and in extending current imaging capabilities in both civilian and military uses.
X-ray nanofocusing by kinoform lenses: A comparative study using different modeling approaches

We conduct a comparative study on various kinoform lenses (KLs) for x-ray nanofocusing by using the geometrical theory, the dynamical diffraction theory, and the beam propagation method. This study shows that the geometrical theory becomes invalid to describe the performance of a KL for nanofocusing. The strong edge diffraction effect from individual lens element, which distorts the desired wave field, leads to a reduction in the effective numerical aperture and imposes a limit on how small a focus a KL can achieve. Because this effect is associated with a finite thickness of a lens, larger lens thickness depicts a stronger distortion. We find that a short KL where all lens elements are folded back to a single plane shows an illumination preference: if the illuminating geometry is in favor of the Bragg diffraction for a focusing order, its performance is enhanced and vice versa. We also find that a short KL usually outperforms its long version where all lens elements do not lie in a single plane because the short one suffers less the wave field distortion due to the edge diffraction. Simulation results suggest that for a long KL, an adaptive lens design is needed to correct the wave field distortion in order to achieve a better performance.
Generating and reintegrating geospatial data

The process of building a geospatial component to access existing materials in the Perseus Digital Library has raised interesting questions about the interaction between historical and geospatial data. The traditional methods of describing geographic features' names and locations do not provide a complete solution for historical data such as that in the Perseus Digital Library. Very often data sources for a spatial database must be created from the historical materials themselves.
Assignment of the REST gene to 4q12 by fluorescence in situ hybridization

This report describes the localization of the REST (RE1-silencing transcription factor) gene to human chromosome 14q12 using fluorescence in situ hybridization. This gene plays a role in the regulation of certain genes exclusively in neurons. 12 refs., 1 fig.