cssi/SciSciGPT-SciSciNet huggingface dataset:
Extensive structural conservation exists among several homologs of two Euglena chloroplast group II introns.

82 of the 155 chloroplast introns in Euglena gracilis have been categorized as group II introns. Because they are shorter and more divergent than group II introns from other organisms, the assignment of these Euglena introns to the group II class has been questioned. In the current study, two homologs of E. gracilispetB intron 1 and four homologs of psbC intron 2 have been isolated from related species and characterized. Based on a comparative sequence analysis of intron homologs, the intron core and four of the six helical domains present in the canonical group II intron structural model are conserved in E. gracilispetB intron 1 and psbC intron 2 and all of their homologs. Distal portions of domain I, which are involved in most of the tertiary interactions, are less well conserved than the central core.
Near-wake structure of an oscillating cylinder : effect of controlled shear-layer vortices

The instantaneous structure of the near wake of a cylinder subjected to small-amplitude perturbations is characterized using high-image-density particle image velocimetry. Emphasis is on control of the small-scale shear-layer vortices, which feed into the Karman vortices. Modifications of the Karman vortex formation are classified according to patterns of modulated and locked-on shear-layer vortices. The formation length of the Karman vortices can be dramatically shortened and, in the limiting case, occur adjacent to the base of the cylinder when it is perturbed at the inherent instability frequency of the shear layer and its subharmonics. Moreover, the induced shear-layer vortices can lead to large-amplitude transverse undulations of the entire near-wake region during formation of the Karman vortices. These variations of the near-wake structure are further elucidated by considering the transient response of the wake, induced by abrupt cessation and onset of periodic motion of the cylinder. Distinctive intermediate states of the wake arise during relaxation to its asymptotic state ; such relaxation requires a very large number of periods of the inherent instability of the shear layer.
Regulation of algal structure and function by nutrients and grazing in a boreal wetland

We evaluated the potential for grazers to regulate benthic algal biomass and taxonomic composition in an Alaskan marsh after enrichment with nutrients that are expected to increase in the region with ongoing climate change. We nested caged and uncaged substrates together inside mesocosm enclosures with natural abundances of snails or no snails and with or without nutrient enrichment (NO3 + PO4 + Si). Algal biomass was greater in all nutrient-enriched enclosures than in controls. Algal biomass was greater in enclosures where grazers were present but excluded by a cage than in enclosures where grazers were allowed to graze or where grazers were absent. In the presence of nutrients, grazed communities were dominated by small coccoid green algae and cyanobacteria, which were overgrown by filamentous green algae when grazers were excluded. In the absence of nutrients, grazers had little effect on algal biomass or taxonomic composition. However, grazers recycled a small but potentially important amount of nutrients in their waste, suggesting that consumer-driven nutrient recycling may have played a role in maintaining algal biomass when grazers were present. Our data show that grazers regulate algal responses to nutrients by suppressing algal accumulation but increasing productivity through nutrient recycling in a northern boreal wetland.
Genetic microdifferentiation in the Semai Senoi of Malaysia

Blood samples, demographic and cultural data were collected from seven settlements of Semai Senoi, a swidden farming ethnic group of Malaysia. Three genetic loci (ABO blood group, hereditary ovalocytosis, and hemoglobin) were analyzed in a total sample of 546 individuals. These data indicate a considerable degree of genetic microdifferentiation in this area of the Semai distribution. Parent-offspring birthplace data (analyzed by means of a migration matrix) and settlement histories show that settlements are not strongly isolated. Genetic differences in the study area demonstrate a reasonable correspondence with migration and the history of the settlements. Genetic microdifferentiation among the Semai is due to recurrent founder effect. Genetic convergence also occurs through the addition of migrant groups to established populations leading to new patterns of marriage between donor and recipient groups. The genetic structure of the total Semai population through time thus comprises a mosaic of shifting allele frequencies in a series of semi-isolated local populations.
Forced regressive and lowstand Hudson paleo-Delta system: Latest Pliocene growth of the outer New Jersey shelf

Abstract Interpretation of the latest Pleistocene stratigraphy of the outer New Jersey shelf has evolved over the last three decades with addition of new geological and geophysical data. During the last decade, new results have described and interpreted various depositional elements within the latest Pleistocene that overlie the regional reflector known as the R-horizon. On the basis of observations made from detailed mapping of the R-horizon and the overlying sediment wedge(s) using high resolution shallow seismic (CHIRP) data acquired in several phases between 2001 and 2006, we revise the depositional model for the offlapping, multi-clinothem sediment wedge on the latest Pleistocene outer New Jersey Shelf as strike-elongated lobes of a falling-stage, wave-influenced delta system fed by a pre-LGM paleo-Hudson River Channel(s) that probably reached the late Pleistocene shelf-edge off New Jersey. This sediment wedge is composed of a series of prograding and offlapping clinothems of varying thickness. Within our data, which does not extend to the basinward termination of the wedge, we seldom observe preserved topsets of these clinothems. Parts of the foresets of some clinothems are also not preserved, particularly in the proximal part of the wedge. The sediment wedge is elongated in strike direction (NNE–SSW), which suggests along-strike sediment movement and possible redistribution of sediment in that direction, by ambient shore-parallel currents. Our data do not record any time-equivalent fluvial channels at the proximal end of the sediment wedge, though there are channel features that cap and cut down into several of the clinothems that make up the wedge farther seaward. We suggest that this can be explained in two possible ways: 1) relatively large spatial separation between the prograding front of the delta system and the delta-plain topset deposits, as is very common under a falling-stage sea-level condition; and 2) lack of preservation of the stratigraphic record of the delta-plain channels because of the likely vigorous falling-stage erosion of topsets during the fall of sea level, and possibly also during the subsequent transgressive ravinement and flooding after the LGM. The clinothems within the sediment wedge show systematic variation in thickness, indicating a northward shift of the main depocenter. This shift might also be an indication of gradual northward migration of the principal fluvial feeder. Such a possibility is supported by previously reported late Pleistocene paleo-Hudson Channel deposits south of the modern Hudson Shelf Valley.
Uterine Papillary Serous Carcinoma (UPSC): A Clinicopathologic Study of 30 Cases

Abstract Between 1975 and 1989, 896 patients were treated for endometrial carcinoma at the Massachusetts General Hospital. Thirty patients were identified from the tumor registry as having uterine papillary serous carcinomas. The survival for all patients and for groups of patients stratified on clinical and pathological parameters was examined in the Kaplan–Meier survival curves. Curves for the different strata were compared using the logrank test. The 5-year survival for the 30 patients was 30% ± 9%. Patients with surgical stage I and II tumors had a 5-year survival rate of 79% ± 14% compared to 25% ± 10% in patients with stage III and IV tumors ( P = 0.02). Clinical stage, depth of myometrial invasion, lymph–vascular space invasion, tumor grade, and DNA aneuploidy were not found to significantly impact on survival. However, a survival advantage was seen in patients diagnosed with early surgical stage tumors, reinforcing the need for thorough staging at the time of laparotomy.
Directed-polymer systems explored via their quantum analogs: Topological constraints and their consequences

The equilibrium statistical mechanics of classical directed polymers in two dimensions is well known to be equivalent to the imaginary-time quantum dynamics of a 1+1-dimensional many-particle system, with polymer configurations corresponding to particle world-lines. This equivalence motivates the application of techniques originally designed for one-dimensional many-particle quantum systems to the exploration of many-polymer systems, as first recognized and exploited by de Gennes [J. Chem. Phys. 48, 2257 (1968)]. In this low-dimensional setting interactions give rise to an emergent polymer fluid, and we examine how topological constraints on this polymer fluid (e.g., due to uncrossable pins or barriers) and their geometry give rise to strong, entropy-driven forces. In the limit of large polymer densities, in which a type of mean-field theory is accurate, we find that a pointlike pin causes a divergent pileup of polymer density on the high-density side of the pin and a zero-density region (or gap) of finite area on the low-density side. In addition, we find that the force acting on a pin that is only mildly displaced from its equilibrium position is sub-Hookean, growing less than linearly with the displacement, and that the gap created by the pin also grows sublinearly with the displacement. By contrast, the forces acting between multiple pins separated along the direction preferred by the polymers are super-Hookean. These nonlinear responses result from effective long-ranged interactions between polymer segments, which emerge via short-ranged interactions between distant segments of long polymer strands. In the present paper, we focus on the case of an infinitely strong, repulsive contact interaction, which ensures that the polymers completely avoid one another. In a companion paper, we consider the effects of a wider set of interpolymer interactions.
Enhancing vapor generation at a liquid-solid interface using micro/nanoscale surface structures fabricated by femtosecond laser surface processing

Femtosecond Laser Surface Processing (FLSP) is a versatile technique for the fabrication of a wide variety of micro/nanostructured surfaces with tailored physical and chemical properties. Through control over processing conditions such as laser fluence, incident pulse count, polarization, and incident angle, the size and density of both micrometer and nanometer-scale surface features can be tailored. Furthermore, the composition and pressure of the environment both during and after laser processing have a substantial impact on the final surface chemistry of the target material. FLSP is therefore a powerful tool for optimizing interfacial phenomena such as wetting, wicking, and phasetransitions associated with a vapor/liquid/solid interface. In the present study, we utilize a series of multiscale FLSPgenerated surfaces to improve the efficiency of vapor generation on a structured surface. Specifically, we demonstrate that FLSP of stainless steel 316 electrode surfaces in an alkaline electrolysis cell results in increased efficiency of the water-splitting reaction used to generate hydrogen. The electrodes are fabricated to be superhydrophilic (the contact angle of a water droplet on the surface is less than 5 degrees). The overpotential of the hydrogen evolution reaction (HER) is measured using a 3-electrode configuration with a structured electrode as the working electrode. The enhancement is attributed to several factors including increased surface area, increased wettability, and the impact of micro/nanostructures on the bubble formation and release. Special emphasis is placed on identifying and isolating the relative impacts of the various contributions.
Radiation epidemiology: a perspective on Fukushima

For nearly 100 years, epidemiologic studies of human populations exposed to ionising radiation have provided quantitative information on health risks. High dose deterministic (tissue reaction) effects result when sufficient numbers of functioning cells are killed, such as in bone marrow depression that can lead to death. Lower dose stochastic effects are probabilistic in nature and include an increased risk of cancer later in life and heritable genetic defects, although genetic conditions in the children of irradiated parents have yet to be convincingly demonstrated. Radiation studies are of diverse populations and include not only the Japanese atomic bomb survivors, but also patients treated with radiation for malignant and non-malignant disease; patients exposed for diagnostic purposes; persons with intakes of radionuclides; workers occupationally exposed; and communities exposed to environmental and accidentally released sources of radiation. Much is known about radiation and its risks. The major unanswered question in radiation epidemiology, however, is not whether radiation causes cancer, but what the level of risk is following low dose (<100 mSv) or low dose rate exposures. Paracelsus is credited with first articulating that the 'poison is in the dose', which for radiation epidemiology translates as 'the lower the dose, the lower the risk' and, an important corollary, the lower the dose, the greater the difficulty in detecting any increase in the number of cancers possibly attributable to radiation. In contrast to the Chernobyl reactor accident, the Fukushima reactor accident has to date resulted in no deterministic effects and no worker deaths. Estimates to date of population doses suggest very low uptakes of radioactive iodine which was a major determinant of the epidemic of thyroid cancer following childhood exposures around Chernobyl. The estimates to date of population doses are also much lower (and the distribution much narrower) than the doses for which cancer excesses have been detected among atomic bomb survivors after 60 years of follow-up. Studies of populations exposed to low doses are also limited in their ability to account for important lifestyle factors, such as cigarette smoking and medical x-ray exposures, which could distort findings. Studies of the Fukushima population should be and are being considered for reassurance and health care reasons. Apart from as regards the extreme psychological stress caused by the horrific loss of life following the tsunami and the large-scale evacuation from homes and villages, such studies have limited to no chance of providing information on possible health risks following low dose exposures received gradually over time--the estimated doses (to date) are just too small.
Mechanisms of Hypersecretion in Rodent Tracheal Explants after Exposure to Chrysotile Asbestos: Studies Using Lectins

H ypertrophy and hyperplasia of mucin-secreting cells occur in the airways after inhalation of noxious agents including tobacco smoke,1 and sulfur dioxide.” Although the cellular mechanisms are undefined, one might speculate that specific interactions between irritants and the plasma membrane of the mucin cell tngger hypersection. We report here an experimental approach to test this hypothesis. Chrysotile asbestos interacts with cellular membranes causing release of lysosomal and cytoplasmic enzymes and hemolysis of red blood cells.” Moreover, a rapid increase of acidic (alcian blue-PAS-positive) secretory granules is observed in the epithelium after addition of chrysotile to tracheal organ cultures and grafts.5 In our studies, lectins with a high affinity for monoand oligosaccharides were used to determine if asbestosinduced hypersecretion is regulated by the interaction of the fiber with specific carbohydrate residues on the mucin cell.
The first heart sound in atrial septal defect

Abstract An electrocardiographic, phonocardiographic, and right-sided cardiovascular pressure study was made in 18 cases of atrial septal defect. The study was primarily concerned with the various components (a, b, and c) of the first heart sound (I) and their relationship to the dynamic events of the right heart. The following facts were ascertained. (1) The average Q-Ia interval is prolonged. (2) The Ia-Ib and Ia-Ic intervals are normal. (3) The Q-Ib interval is much longer than the Q-right ventricular pressure rise. (4) The Q-Ib interval is even longer than the Q-pulmonary artery pressure rise. (5) Both the a and b components have a close relationship with the secondary accidents of the tracing of the first derivative (dpdt) of left ventricular pressure. As a result of these measurements, the Ib component should be considered as unrelated to closure of the tricuspid valve. Other considerations are made in regard to the amplitude of the various components of the first heart sound in atrial septal defect.
CONSUMERISM AND THE REGULATORY SYSTEM: PARADIGMS OF REFORM

The problem of protecting consumer interests in the regulatory process is viewed from the free enterprise, progressive, and pluralist paradigms. Berman considers the characteristics of each paradigm, the ways reformers have sought to implement each, and how they interact and shape the nature of the regulatory system. The greatest conflict lies between the free enterprise and progressive paradigms on the need for regulation. The author concludes, however, that the regulatory system can best be viewed as a blend of the different paradigms–unstable though that blend may be.
Combined PIV/PLIF measurements of a steady density current front

A novel method for combined particle image velocimetry and laser induced fluorescence is described and results from an experiment in a stratified flow are presented. A standard two-dimensional, one camera particle image velocimetry configuration is used, acquiring images of the seeding particles and the dye marking the current simultaneously and separating the two fields digitally. The implementation of the postprocessing method, its capabilities and the necessary conditions for its use are discussed in detail. The proposed method is applied to an arrested density current front. The front is made stationary by opposing a uniform velocity profile, obtained from the combination of a moving floor and the recirculation of fresh water in the channel. To improve the quality of the images, the current is made optically homogeneous by matching the refractivity index throughout the domain. Instantaneous and time averaged fields are obtained for both velocity and density. Simultaneous measurements of these fields provide insight in the mixing processes at the front of the density current. In particular persistent billow generation, similar to that found in shear layers and associated with Kelvin–Helmholtz instabilities, is observed.
ULTRASTRUCTURE OF CARDIAC MUSCLE AND NERVE CONTIGUITIES

FIOURE 1 This electron micrograph shows a nerve process (gr) containing predominantly granular vesicles which makes intimate contact with the surface of a cardiac muscle cell (arrows). A portion of a nerve process (affr) containing only agranular vesicles is situated above the other nerve process. Serial sections would most likely show these two nerve processes lying side-by-side, g, glycogen particles; p, protrusion of cardiac muscle cell; grv, large granular vesicles. Myocardium of the apex of, the ventricle of frog heart. X 40,000.
Olfactory Organ of Channel Catfish as a Site of Experimental Edwardsiella ictaluri Infection

Abstract Edwardsiella ictaluri, the causative agent of enteric septicemia of catfish (ESC), is one of the most important pathogens to infect channel catfish Ictalurus punctatus. Although the full pathogenesis of E. ictaluri is unclear, the olfactory organ is thought to be a site of entry. We have examined the effects of applying E. ictaluri directly into the olfactory capsule of channel catfish. Olfactory organs of 30 experimental fish were exposed to E. ictaluri for 1 h (1 mL, 1 × 106 colony-forming units/mL). Live fish were sampled at 1, 24, 48, and 72 h, and days 5 and 14 postinfection, and their olfactory organs were examined by light and electron microscopy. Damage, including loss of sensory cilia and microvilli from the olfactory mucosal surface, was observed at 1 h postinfection. Degeneration of olfactory receptors and supporting cells was evident by 24 h postinfection. The nonsensory region also showed signs of degeneration, such as columnar cells lacking cilia. Electron microscopic immunocytochem...
Pc2 and SUMOylation

Polycomb proteins are key regulators of transcription in metazoan organisms. Recent work has shed light on the nature of the polycomb protein complexes in flies and mammalian cells. Multiple enzymatic activities have been shown to associate with polycomb complexes, including histone methyltransferase, histone deacetylase and ubiquitination activities, which are primarily directed towards the modification of chromatin structure. In addition to these chromatin-based functions, other potential roles for polycomb proteins exist. Here, we present a comparison of vertebrate Pc2 (polycomb 2 protein) homologues, and review the known functions of the mammalian Pc2 focusing on its role as a SUMO (small ubiquitin-related modifier) E3 ligase. Pc2 is an E3 for several SUMO substrates, but still appears to have a more limited repertoire than other SUMO E3s, perhaps due to its association with polycomb complexes. One possibility is that Pc2 represents a relatively specialized polycomb protein, which has additional functions to those associated with other mammalian Pc (polycomb protein) paralogues.
Dosage-Dependent Regulation of Pancreatic Cancer Growth and Angiogenesis by Hedgehog Signaling

Summary Pancreatic cancer, a hypovascular and highly desmoplastic cancer, is characterized by tumor expression of Hedgehog (HH) ligands that signal to fibroblasts in the surrounding stroma that in turn promote tumor survival and growth. However, the mechanisms and consequences of stromal HH pathway activation are not well understood. Here, we show that the HH coreceptors GAS1, BOC, and CDON are expressed in cancer-associated fibroblasts. Deletion of two coreceptors ( Gas1 and Boc ) in fibroblasts reduces HH responsiveness. Strikingly, these fibroblasts promote greater tumor growth in vivo that correlates with increased tumor-associated vascularity. In contrast, deletion of all three coreceptors ( Gas1 , Boc , and Cdon ) results in the near complete abrogation of HH signaling and a corresponding failure to promote tumorigenesis and angiogenesis. Collectively, these data identify a role for HH dosage in pancreatic cancer promotion and may explain the clinical failure of HH pathway blockade as a therapeutic approach in pancreatic cancer.
Viability of fifty-five neoplasms after storage in liquid nitrogen.

Abstract Fifty-five neoplasms of mice, rats, and hamsters and of human cell origin have been stored at liquid nitrogen temperature for periods up to 1 year after slow freezing with a Canalco controlled temperature unit. Fifty-three of these tumors have remained viable, and only the Ridgeway osteogenic sarcoma and the 3,4,9,10 dibenzpyrene-induced fibrosarcoma in the random-bred mouse became nonviable. Trypan blue dye exclusion tests on ascites tumors showed an apparent survival of 40 to 95% of the cells after storage, without, however, producing any significant changes in mean survival times when implanted into new hosts. Continuous animal passage revealed changes within 6 months in virulence (increase or decrease in mean survival times) of the Gardner lymphosarcoma, P815 mast cell leukemia, and 70429 plasma cell leukemia, whereas lines from the tumor bank did not demonstrate these changes. Chemotherapeutic tests of 23 neoplasms after storage for 1 year in liquid nitrogen demonstrated that freezing and storage did not affect the sensitivity (or resistance) of these neoplasms to the standard agents tested.
Comparison of metabolic, ventilatory, and neurohumoral responses during light forearm isometric exercise and isotonic exercise in congestive heart failure

Maximal treadmill exercise responses were compared with light forearm isometric exercise responses in patients with chronic, stable heart failure (n = 14), and normal sedentary controls (n = 11). Isometric exercise was performed to exhaustion with 25% of maximal voluntary contraction. Gas-exchange analysis was used to determine oxygen consumption (VO2), carbon dioxide production (VCO2), and minute ventilation (VE) during exercise. Significant correlations were observed in normal controls, but not in patients with heart failure, between peak isotonic exercise and peak isometric exercise for VO2 (r = 0.75, p = 0.001) and VCO2 (r = 0.67, p < 0.03), and between submaximal isotonic exercise (50% of peak) and peak isometric exercise for VO2 (r = 0.75, p = 0.007), VCO2 (r = 0.67, p = 0.02), and VE (r = 0.71, p = 0.01). At 90 seconds after isometric exercise in both groups, significant correlations t < 0.05) were observed with peak isotonic exercise VE (r = 0.62 normals, and r = 0.63 heart failure). Plasma norepinephrine increased significantly (p < 0.01) after both isotonic and isometric exercise in patients with heart failure, although peak values were greater with isotonic than with isometric exercise (p = 0.01). Plasma atrial natriuretic peptide and renin activity did not change with either isotonic or isometric exercise. In conclusion, maximal isotonic exercise responses are not predictive of peak isometric VO2 or VCO2 in patients with heart failure. However, VE during maximal isotonic exercise predicts postisometric exercise ventilation in both normals and patients with heart failure; this may determine the extent of dyspnea that patients with heart failure experience with isometric activities of daily living.
PORK IN THE ANTE-BELLUM SOUTH: THE GEOGRAPHY OF SELF-SUFFICIENCY1

ABSTRACT Traditional interpretation of the Ante-Bellum southern economy has assumed a widespread and chronic shortage of food, especially pork. Comparison of pork production with estimated consumption, however, reveals that the level of subsistence varied markedly within the South. The major areas whose production was far below their needs were Louisiana and coastal South Carolina. Other areas with lesser shortages were some western Mississippi counties adjacent to the river, the Gulf Coast counties of Alabama and Mississippi, the Black Belt of Alabama, and parts of the Georgia-Carolina Piedmont. Although a number of counties were deficient, the greater part of the area produced pork sufficient for local needs. In fact, the Hill South sent huge surpluses to market in both the East and the South. The pork deficiencies were made up either by shipments of live animals overland from the Hill States or by western pork via the Mississippi waterway. South Carolina and Louisiana were the major markets for extra-r...
An experimental investigation of pure tone generation by vortex shedding in a duct

An experimental investigation has been carried out for acoustic oscillations sustained by flow through a duct containing two baffles. Pure acoustic tones corresponding to longitudinal resonant modes of the duct are produced when certain flow and geometrical conditions are satisfied. The conditions are such as to ensure close coincidence between the frequency of vortex shedding from the forward baffle, and a natural frequency of the duct. Flow visualization has shown that under these conditions a stable vortex structure exists between the baffles, containing at all times an integral number of vortices.
Thermodynamic Effects on Organismal Performance: Is Hotter Better?

Abstract Despite decades of research on the evolution of thermal physiology, at least one fundamental issue remains unresolved: whether the maximal performance of a genotype depends on its optimal temperature. One school argues that warm‐adapted genotypes will outperform cold‐adapted genotypes because high temperatures inevitably accelerate chemical reactions. Yet another school holds that biochemical adaptation can compensate for thermodynamic effects on performance. Here, we briefly discuss this theoretical debate and then summarize empirical studies that address whether hotter is better. In general, comparative and experimental studies support the view that hotter is better. Furthermore, recent modeling has shown that thermodynamic constraints impose unique selective pressures on thermal sensitivity. Nevertheless, the thermodynamic effect on maximal performance varies greatly among traits and taxa, suggesting the need to develop a more sophisticated view of thermodynamic constraints.
Transforming growth factor‐β1 in the developing mouse pancreas: a potential regulator of exocrine differentiation

Transforming growth factor-beta 1 (TGF-beta 1) is known to regulate cell growth, differentiation, and function in developing mammalian systems. Altering TGF-beta 1 expression in the developing pancreas has been shown to affect both exocrine and endocrine development, suggesting that it is an important regulator of pancreatic organogenesis. We proposed to examine the ontogeny of TGF-beta 1 mRNA expression in the developing pancreas, as well as characterize the patterns of relative TGF-beta 1 gene expression and activity. We performed in situ hybridization for TGF-beta 1 on pancreas specimens obtained from CD-1 mice on gestational days 12.5 (E12.5), 15.5 (E15.5), and 18.5 (18.5). We also isolated mRNA from the pancreas on each of these days and performed a semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) to assess relative TGF-beta 1 expression as a function of gestational age. Finally, we performed a TGF-beta 1 ELISA with media conditioned by embryonic pancreas from gestational days 15.5 and 18.5. By in situ hybridization, TGF-beta 1 mRNA is expressed exclusively in the E12.5 pancreatic epithelium, sparing the surrounding mesenchyme. As pancreatic organogenesis progresses, TGF-beta 1 mRNA expression localizes predominantly to the developing acini. TGF-beta 1 gene expression appears modest through E15.5 but is upregulated near the end of gestation, at E18.5. TGF-beta 1 activity, by ELISA, is also upregulated at E18.5. TGF-beta 1 may thus be a modulator of pancreatic organogenesis. Modest TGF-beta 1 expression through E15.5 may be permissive for exocrine lineage selection. TGF-beta 1 expression may then become critical for terminal acinar differentiation. Upregulated TGF-beta 1 expression at the end of gestation may be important for islet formation, and it may be necessary to inhibit continued proliferation and differentiation of pluripotent cells within the pancreatic ductal epithelium.
Candidate genes showing no evidence for association or linkage with Alzheimer's disease using family-based methodologies.

Alzheimer’s disease (AD) is a genetically complex and heterogeneous disorder. To date, a large number of candidate genes have been associated with the disease, however none of these findings has been consistently replicated in independent datasets. In this study we report the results of family-based analyses for polymorphisms of five such candidates on chromosomes 2 (interleukin-1b, IL-1B), 3 (butyrylcholinesterase, BCHE), 11 (cathepsin D, CTSD; Fe65, APBB1) and 12 (lipoprotein receptorrelated protein-1, LRP1) that were all suggested to be associated with AD in recent case-control studies. To minimize the possibility of spurious findings due to population admixture, we used a family-based design applying the sibship disequilibrium test (SDT) as well as two-point parametric linkage analyses on families from the National Institute of Mental Health (NIMH) Genetics Initiative. Contrary to the initial reports, none of the polymorphisms that were analyzed showed evidence for association or linkage with AD in our families. Our results suggest that the previously reported associations from case-control studies are either (a) false positive results, e.g. due to type I error or population admixture, (b) smaller than initially proposed, or (c) due to linkage disequilibrium with an as yet unidentified polymorphism nearby. q 2000 Elsevier Science Inc. All rights reserved.
Implications of Microsoft Vista operating system for computer forensics investigations

With the growing importance of computer-related evidence today, it is important for law enforcement, prosecutors and computer forensics investigators to understand changes in their technical environment that are impacting the discovery and nature of evidence. Microsoft's Vista (“Vista”) is one change that has brought new challenges for digital investigations, particularly relating to new mechanisms of encryption and general security. This paper will identify those challenges and prescribe possible solutions. More specifically this research proposes practical ways in which the digital investigator can retrieve critical file metadata, explore file systems and record log files. The focus of this paper will be on the changes to Microsoft's New Technology File System (NTFS). In general, Vista has placed a greater emphasis on file sharing across the Internet so XML file formats are more pervasive. Security, and more specifically encryption, is more prevalent in Vista and so this paper will focus on changes to Windows Mail. Although there is no empirical evidence, it appears as though prosecutors heavily rely on electronic mail evidence. With the continuous expansion in size of flash memory, it was imperative to note changes to the digital footprint left by USB thumbdrives as well as the impact of Microsoft's new volatile memory expansion tool - readyboost. Log files are also a crucial source of evidence in computer forensics investigations and these are discussed in great detail as changes in Vista have changed the nature of this evidence. This research paper will discuss the relevance of changes to evidence in Vista by highlighting the use of certain evidentiary files in court cases. Finally, the implications of changes brought about by Vista will be made apparent through experiments conducted with bit-stream imaging tools utilized by law enforcement and other computer forensics examiners. Vista has notable implications for computer forensics investigations. However, this research will prepare the digital investigator for the transition to the Vista operating system and the transformation of digital evidence associated with this new platform.
Iron Sulfide and Carbonate Mineral Diagenesis in Baffin Bay, Texas

ABSTRACT In anoxic sediments, bacterially-mediated sulfate reduction can play a major role in both carbonate and sulfide mineral diagenesis. In order to understand better the complex interrelationships involved in these diagenetic processes, diagenesis of iron sulfide and carbonate minerals was studied in the poorly-sorted siliclastic-dominated sediments from Baffin Bay, Texas. The production of pyrite dominantly takes place in the top 20 cm of sediment. A good correlation (r2 = 0.76) is observed between the total inorganic sulfur (TRS) content of the sediments and the percentage of the sediment that is fine-grained ( 0.8) degrees of Fe pyritization, and elevated C/S ratios compared to normal marine sediments indicate that reactive iron probably limits sulfide burial in sediments from this region containing more than about 1 wt. % organic carbon. A major ( 10 fold) increase in CO2 driven by sulfate reduction is closely related to a large decrease in dissolved calcium in the upper 1 m of sediment. The major decrease in dissolved calcium is probably due to the precipitation of calcium carbonate. Dolomite was observed in these sediments, and favorable conditions for its formation are present. However, a detrital origin for the dolomite cannot be ruled out.
Influence of extracellular magnesium on capillary endothelial cell proliferation and migration

We investigated the role of extracellular magnesium on capillary endothelial cell migration and proliferation, components of endothelial cell function that play an important role in angiogenesis and wound healing. Cell migration and proliferation were tested in six different MgSO4 concentrations and in various culture conditions. The Boyden chamber procedure was used to evaluate migration of bovine adrenal cortex capillary endothelial cells. We found that low magnesium concentration inhibited cell migration, but a dose-dependent increase in migration was observed when magnesium level was increased beyond the normal serum concentration (up to 2.4 mM magnesium; p less than 0.0001). Cell proliferation was also inhibited by very low magnesium concentration, an effect observed under all conditions studied. When cell proliferation was stimulated by acidic or basic fibroblast growth factors, it appeared that a ceiling was reached, an increasing magnesium concentration had no additional stimulatory effect. However, a dose-dependent increase in proliferation (p less than 0.005) was observed when magnesium concentration was increased above the normal serum level (0.8 mM) in culture conditions that did not cause marked cell proliferation. Thus, magnesium has an important role in endothelial cell migration and proliferation: very low extracellular magnesium concentrations inhibit and supranormal levels enhance both migration and proliferation. These results suggest that magnesium deficiency might adversely influence the healing and reendothelialization of vascular injuries and the healing of myocardial infarction and might also result in delayed or inadequate angiogenesis, effects potentially leading to infarct expansion and inadequate collateral development.
Ischemic heart disease

In this edition of the Journal, we release the first in a series of reviews of influential articles that have been previously published in ACC journals, including the American Journal of Cardiology (from 1958 to 1982), and JACC (from 1983 to the present). The publication of these articles is only
Regulatory perspective on characterization and testing of orthopedic bone cements

Abstract This paper provides a general regulatory background of acrylic bone cements, chemical composition informaion on serveral commercially available bone cements, physical and chemical methods of analyses, mechanical test methods, and risks and failure mechanisms of acrylic bone cements. Suggestions and recommendations presented in Tables 2 and 3 are not mandatory requirements but reflect data and methodologies which the FDA’s Orthopedic Devices Branch (ORDB) believes to be acceptable to evaluate most pre-clinical data. FDA may require information in addition to that contained in this paper. In some instances, a sponsor may be able to sufficiently justify the omission of some tests. Although this paper describes certain administrative requirements, it does not take the place of the requirements contained ion Title 21 of the Code of Federal Regulations (21 CFR) Parts 801, 807, 812, and 814 or those found in the statute.
Action of Cortisol on Sodium Transport in Canine Erythrocytes

Incubation of blood from deoxycorticosterone-treated, adrenalectomized dogs with glucose, 22NaCl, and cortisol, added in vitro, revealed log dose-related acceleration of sodium influx, of glucose utilization, and of lactate formation by cortisol in concentrations between 150 and 1000 µg/liter. Addition of 2-deoxyglucose, or preincubation of the blood until blood glucose concentration had fallen below 2.0 mg per 100 ml, reduced or abolished the acceleratory action of added cortisol on sodium influx but had no effect on sodium influx in the absence of added cortisol. Cortisol did not change the ATP or ATPase content of erythrocytes, or the metabolism of glucose via the pentose phosphate pathway, or the rate of efflux of 22Na from the erythrocytes. The acceleratory actions of cortisol on sodium, influx, glucose utilization, and lactate formation were significantly correlated. Cortisol (1000 µg/liter) enhanced sodium influx by approximately 8.7 mmole per liter erythrocytes per hour for each 1 mmole cortisol-induced increment in ATP production. It is concluded that sodium influx in canine erythrocytes comprises a passive component, unchanged by cellular metabolism, and a second component which is accelerated and inhibited in proportion to prevailing plasma concentrations of cortisol and aldosterone, and which (for cortisol) depends upon accelerated ATP production via glycolysis. These steroid actions probably result from effects on enzyme activity rather than on new enzyme induction.
Multicarrier Interactions in Semiconductor Nanocrystals in Relation to the Phenomena of Auger Recombination and Carrier Multiplication

Chemically synthesized semiconductor nanocrystals (NCs) have been extensively studied as a test bed for exploring the physics of strong quantum confinement and as a highly flexible materials platform for the realization of a new generation of solution-processed optical, electronic, and optoelectronic devices. Because of readily tunable, size-dependent emission and absorption spectra, colloidal NCs are especially attractive for applications in light-emitting diodes, solid-state lighting, lasing, and solar cells. It is universally recognized that the realization of these and other prospective applications of NCs requires a detailed understanding of carrier-carrier interactions in these structures, as they have a strong effect on both recombination and photogeneration dynamics of charge carriers. For example, nonradiative Auger recombination is one of the key factors limiting the performance of NC-based lasers and light-emitting diodes. The inverse of this process, carrier multiplication, plays a beneficial ...
SCAR - Scattering, Concealing and Recovering Data within a DHT

This paper describes a secure and reliable method for storing data in a distributed hash table (DHT) leveraging the inherent properties of the DHT to provide a secure storage substrate. The framework presented is referred to as ";Scatter, Conceal, and Recover"; (SCAR). The standard method of securing data in a DHT is to encrypt the data using symmetrical encryption before storing it in the network. SCAR provides this level of security, but also prevents any known cryptoanalysis from being performed. It does this by breaking the data into smaller blocks and scattering these blocks throughout the DHT. Hence, SCAR prevents any unauthorized user from obtaining the entire encrypted data block. SCAR uses hash chains to determine the storage locations for these blocks within the DHT. To ensure storage availability, SCAR uses an erasure coding scheme to provide full data recovery given only partial block recovery. This paper first presents the SCAR framework and its associated protocols and mechanisms. The paper then discusses a prototype implementation of SCAR, and presents a simulation-based experimental study. The results show that in order for the erasure coding techniques used by SCAR to be effective, P2P nodes must sufficiently available.
Procurement Contracts: Fixed Price vs. Cost Plus

Economists have applied the methodology of information economics and contract theory (mechanism design) to problems in procurement and regulation. With the standard adverse selection and moral hazard components, the principal should offer a menu of incentive contracts from which the employed firm (agent) will select a contract that reveals its hidden information. In reality, such menus are not observed. Researchers in engineering management have also studied the costs and benefits of alternative contractual arrangements. In this literature, time to completion, project complexity, construction change orders, and risk management are the fundamental problems in the contracting environment. A central conclusion is that "cost-plus" contracts minimize total completion time, while "fixed-price" contracts minimize total project costs. We develop a parsimonious model that formalizes these results and shed new light on the procurement process.
The ED record — Friend or foe

s should be limited to 250 words and typed double spaced on 81/2 '' × 11" paper. "Abstracts must be authored, co-authored or sponsored by a UA/EMS member and the name and address of each author should appear on the abstract. Deadline for submission is October 30, 1976. Mail three copies of the abstract to: Kenneth L. Mattox, MD, UA/EMS, 3900 Capital City Boulevard, Lansing, Michigan 48906 . . . . Presentations at the Annual Meeting will be limited to ten minutes followed by a five-minute panel discussion period. A completed manuscript must be submitted no later than the day of the meeting and will be considered for publication in JACEP, Journal of the American College of Emergency Physicians and the University Association for Emergency Medical Services. Page 540 Volume 5 Number 7 July'1976 , , ,~P
Non‐Conceptive Sexual Behavior in Spiders: A Form of Play Associated with Body Condition, Personality Type, and Male Intrasexual Selection

In the socially polymorphic spider Anelosimus studiosus, males mature early in the reproductive season and recruit to the webs of juvenile females and guard them until they mature. During the period before females mature, males and females engage in repeated bouts of non-conceptive (play) sexual behavior, where the pair courts and engages in mock copulation; both males and females gain performance-enhancing experience via these encounters. In this study, we examined the factors that underlie individual variation in the tendency to engage in non-conceptive mating and determine whether it impacts male–male competition for females. We found that docile females, being less resistant to mating in general, are more likely to accept male courtship and non-conceptive copulation as juveniles. Personality type influenced the exhibition of non-conceptive sexual behavior in males as well. High body condition males of the aggressive phenotype were more likely to engage in non-conceptive sexual behavior than males with lower body condition. Body condition did not influence docile males’ propensity to engage in non-conceptive sexual behavior, but female size did. Docile males engaged in more non-conceptive sexual displays with larger females. Engaging in non-conceptive sexual displays negatively impacted male performance in staged male–male contests for access to females. This cost was greatest for males of the aggressive phenotype, which are otherwise favored in male–male contests. Our findings indicate expression of non-conceptive sexual displays is linked to personality and results in reproductive performance trade-offs for male A. studiosus.
Programmable transversal filter based adaptive line enhancer

A programmable transversal filter (PTF)-based adaptive line enhancer (ALE) subsystem is described. It covers the 30 to 58-MHz frequency range. The PTF-ALE can be utilized with frequency-hopping radio receivers to greatly reduce unwanted RF interference via a quickly programmable null. A subsystem configuration (adaptive line enhancer) and adaptive algorithm (differential steepest descent) are selected. A digitally controlled (TTL) PTF programmed by a standard personal computer with an off-the-shelf direct memory access interface is described. The PTF device has the capability to be reprogrammed at 3 mu sec per tap weight plan. The ALE subsystem consists of a delayed, unity gain channel and a difference channel containing the PTF. The subsystem creates a 40-dB single null, software programmable to any frequency in the range 30 to 58 MHz. The null has a 3-dB bandwidth of 45 KHz. When combined with a fast microprocessor, the PTF-ALF is ideal for excision of narrowband interfering signals in fast hopping communication systems. >