cssi/SciSciGPT-SciSciNet huggingface dataset:
Morphological changes in atretic Graafian follicles during induced atresia in the hamster.

Hypophysectomized female hamsters primed with 30 i.u. pregnant mare serum gonadotropin (PMSG) were injected with anti-PMSG serum 72 h later to induce atresia in Graafian follicles. The earliest histological evidence of atresia was seen in the cumulus oophorus at 4 h with a significant increase in pyknotic nuclei. The mural granulosa cells, however, did not show pyknoses until 12 h following anti-PMSG serum. The highest number of pyknotic nuclei in the cumulus oophorus was seen at 24 h, when pseudomaturation of the oocyte occurred. Breakdown of the mural granulosa cells was greatest by 48 h. Morphometric measurements of the follicles showed a significant decline in the thickness and area by the granulosa layer at 48 h following injection of anti-PMSG serum. The thecal compartment showed a decline in number of mitoses at 4 h and 12 h and in area at 48 h. However, no pyknotic thecal cells were observed during the 72 h following injection of anti-PMSG serum. The results support previous work using this model, which showed major biochemical changes in the granulosa cells at 12 and 48 h. The theca, however, was comparatively unaffected during atresia. The various studies using this model shew changes in atretic follicles similar to those seen in other models and in the intact animal. The major advantage of this medel is that it produces a large synchronous population of follicles that rapidly becomes atretic.
Sorption-Desorption and Solution Concentration of Phosphorus in a Fertilized Sandy Soil

There has been increasing concern about drinking water contamination and accelerated eutrophication of surface water bodies. A field experiment was conducted to assess leaching potential of PO 4 -P in a Riviera fine sand (loamy, siliceous, hyperthermic Arenic Glossaqualf) under grapefruit (Citrus paradisi Macfad.) production that received 0 to 30 kg P ha -1 yr -1 . The PO 4 -P concentration was measured in soil solution sampled using suction lysimeters installed above (120 cm) and below (180 em) the hardpan (argillic horizon). Phosphorus sorption-desorption in soil samples from different depths of the soil profile was determined to understand the transport and leaching of P in the sandy soil. Phosphorus sorption capacity of the argillic horizon was much greater than the soil above and below it. The PO 4 -P concentrations in soil solution varied from 0.031 to 0.976 and from 0.002 to 0.083 mg P L -1 at the 120- and 180-cm depths, respectively. Solution PO 4 -P concentrations generally increased with P application rates. The concentrations of P in solution at the 120-cm depth were much greater than those at the 180-cm depths, due to the greater P retention capacity of and restricted flow of P through the hardpan. This study demonstrates that leaching of P into groundwater was reduced by the presence of a hardpan in the Riviera fine sand. However, the water drained from the soil above the hardpan contains phosphorus and could be a potential P source to surface waters.
Kavalier & Clay, the Comic-Book Novel, and Authorship in a Corporate World

The novelistic tradition of economic individualism was challenged in the twentieth century as the rise of the corporation changed the nature of work and ownership. The author examines contemporary U.S. novels set in the comic-book industry or that use comic-book characters in their narratives. Comic-book narratives reveal particularly clearly the corporate influence on originality and the attempt to claim ownership of artistic creations. The author concludes with Michael Chabon's The Amazing Adventures of Kavalier & Clay, a novel that breaks with this tradition and uses the comic book to redefine the relationship between the individual and the economic landscape.
Nuclear mechanotransduction: Response of the lamina to extracellular stress with implications in aging

Mechnotransduction, the phenomenon by which cells respond to applied force, is necessary for normal cell processes and is implicated in the pathology of several diseases including atherosclerosis. The exact mechanisms which govern how forces can affect gene expression have not been determined, but putative direct force effects on the genome would require transduction through the nuclear lamina. In this study we show that nuclei in cells exposed to shear stress significantly change shape, upregulate nuclear lamins and move lamins from the nuclear interior to the nuclear periphery. We hypothesize that the augmentation of the nuclear lamina at the nuclear periphery protects the nuclear interior from the force and allows a nuclear adaptation to shear stress. We also investigate the shear stress response of nuclei in cells that have been transfected with lamin A Delta50, which significantly stiffens nuclei. Lamin A Delta50 causes the premature aging syndrome Hutchinson-Gilford progeria syndrome (HGPS) and models many aspects of normal aging. We find that the presence of lamin A Delta50 in only 30% of cells greatly reduces the response of the nuclear lamina in all cells in the flow field. We suggest that cells expressing lamin A Delta50 lack the ability to adapt to flow and may prevent neighboring cells from adapting as well. These results provide insight into the development of cardiovascular disease both in patients with HGPS and in normal aging.
Nonthermal Spectral Line Broadening and the Nanoflare Model

A number of theoretical and observational considerations suggest that coronal loops are bundles of unresolved, impulsively heated strands. This ‘‘nanoflare’’ model, as it is sometimes called, predicts high-speed evaporative upflows, which might be revealed as nonthermal broadening of spectral line profiles. We have therefore generated synthetic line profile observations based on one-dimensional hydrodynamic simulations for comparison with actual observations. The predicted profiles for Ne viii (770.4 8), a transition region line, and Mg x (624.9 8), a warm coronal line, have modest broadening that agrees well with existingobservations. The predicted profiles for Fexvii(254.87 8), a hot line that will be observed by the Extreme Ultraviolet Imaging Spectrometer (EIS) on the Solar-B mission, are somewhat broader and are also consistent with the limited number of hot line observations that are currently available. Moreover, depending on the properties of the assumed nanoflare and other parameters of the simulation, the Fe xvii profile can have distinctive enhancements in the line wing. This indicates a powerful diagnostic capability that can be exploited once Solar-B is launched. Subject headingg hydrodynamics — Sun: corona Online material: color figures
Linguistic and Nonlinguistic Features of Style in Normal and Language-Impaired Children

This study explored two questions concerning the language-learning styles described in recent investigations of early child language. The first question was whether features suggestive of language-...
Analysis of discontinuous variation in albumin production by hepatoma cells at the cellular level.

The clonal variation in the rate of albumin production in cultured rat hepatoma cells has been studied on a cellular basis by immunoperoxidase techniques using specific antisera against rat serum albumin. Previously, it has been shown that an array of clonal hepatoma cell populations that produce serum albumin at different rates can be isolated simply by subcloning a single clonal hepatoma cell line (Fu5). The present study demonstrates conclusively that this phenotypic variation is the result of quantal shifts in the rate of albumin production in the individual cells and is not due to changes in the percentage of albumin-producing cells. Also, by analyzing individual colonies as they develop from single cells, it was possible to establish that the rate of variation in albumin content in several hepatoma cell clones is on the order of 0.5–1.4 10−2 per cell per generation. This variation in albumin content probably reflects shifts in the rate of albumin synthesis. Even after several sequential subclonings, the same clonal variation persists. The variants are not the result of fluctuations in albumin synthesis with different phases of the cell cycle.
Value of pancreatic-type isoamylase assay as an index of pancreatic insufficiency

The study here reported was undertaken to assess the value of assay of the specific isomylase form arising from the pancreas (P-type) as an index of pancreatic exocrine insufficiency. Measurements were made of serum total amylase activity, serum P-type isoamylase activity, and the amount of P-type isoamylase relative to creatinie (Upam/Ucr) in the urine in a series of patients with clinically suspected chronic pancreatitis and pancreatic insufficiency as determined from the pancreatic secretory response to secretin stimulation. Abnormally low values for P-type isoamylase in the serum and urine of these patients were infrequent. Conversely, values within the normal ranges for serum P-type isoamylase and Upam/Ucr were common. It is concluded that while subnormal values for P-type isoamylase in the serum and urine may be viewed as supportive evidence for pancreatic insufficiency, failure to find such values does not exclude this condition.
Adhesion and migration of ovarian cancer cells on crosslinked laminin fibers nanofabricated by multiphoton excited photochemistry

Ovarian cancer is the deadliest gynecological cancer, which may arise in part due to the concurrent invasion and metastasis of high grade tumors. It is thus crucial to gain insight into the adhesion and migration mechanisms in vivo, as this may ultimately lead to new treatment/detection options. To explore this possibility, we have used multiphoton excited photochemistry (MPE) to synthesize models of the ovarian basal lamina consisting of crosslinked laminin nanofibers to quantify the adhesion/migration dynamics. The nanostructured laminin patterns permit the systematic comparison of total migration, directed migration, adhesion, and morphology of “normal” immortalized human ovarian epithelial cells (IOSE) and three lines of varying metastatic potential (OVCA433, SKOV-3.ip1, and HEY-1 cells). We find that the migration of all the cell lines is directed by the crosslinked fibers, and that the contact guidance enhances the total migration rates relative to monolayers. These rates increase with increasing metastatic potential, and the more invasive cells are less rigid and more weakly adhered to the nanofibers. The extent of directed migration also depends on the cell polarity and focal adhesion expression. For the invasive cells, these findings are similar to the integrin-independent ameboid-like migration seen for polar cells in collagen gels. Collectively, the results suggest that contact mediated migration as well as decreased adhesion may be operative in metastasis of ovarian cancer in vivo.
A double-blind, placebo-controlled trial of extract of Ginkgo biloba added to haloperidol in treatment-resistant patients with schizophrenia.

BACKGROUND Many studies have indicated that excess free radical formation may be involved in the pathogenesis of patients with schizophrenia. Some investigators suggested that the use of free radical scavengers might provide improvement in schizophrenia. The aim of this study was to determine the effectiveness and to evaluate the side effects of extract of Ginkgo biloba (EGb) plus haloperidol in chronic, treatment-resistant inpatients with schizophrenia. METHOD One hundred nine patients meeting DSM-III-R criteria for schizophrenia completed a double-blind, placebo-controlled, parallel-group study of EGb plus haloperidol. Fifty-six of the patients were randomly assigned to receive a fixed dose of 360 mg/day of EGb plus a stable dose of haloperidol, 0.25 mg/kg/day, and 53 were assigned to receive placebo plus the same dose of haloperidol for 12 weeks. Patients were assessed using the Brief Psychiatric Rating Scale (BPRS), the Scale for the Assessment of Negative Symptoms (SANS), and the Scale for the Assessment of Positive Symptoms (SAPS) at baseline, week 6, and week 12 and the Treatment Emergent Symptom Scale (TESS) for side effects at week 12. RESULTS There was a significant reduction in both groups in BPRS total score after 12 weeks of treatment (p < .05). However, a significant reduction in total SAPS and SANS scores was noted in the EGb group (p < .05), but not in the placebo group. There was a lower SAPS total score in the EGb group than in the placebo group at the end of 12 weeks of treatment (p < .05). Of those treated with EGb plus haloperidol, 57.1% were rated as responders as compared with only 37.7% of those receiving placebo plus haloperidol when assessed by the SAPS (chi2 = 4. 111, p = .043). After 12 weeks of treatment, TESS subscore 1 (behavioral toxicity) and subscore 3 (symptoms of nerve system) were significantly decreased in the EGb group compared with the placebo group (p < .05). CONCLUSION EGb treatment may enhance the effectiveness of antipsychotic drugs and reduce their extrapyramidal side effects.
Six Sigma: issues and problems

Companies are concerned about quality control. There are many methods of controlling quality, such as control charts, Total Quality Management (TQM), Six Sigma and others. However, the current emphasise on Six Sigma suggests that organisations should achieve 3.4 defects per million. Even though it is a target, it is neither practical nor statistically-based on quality control charts. Moreover, the current literature discusses the benefits of Six Sigma without providing solid economic and/or statistical proof that it works. This paper discusses the problems with Six Sigma and shows how it is impractical and statistically unsound. It also suggests that other tried and true quality control methods which have worked and are statistically sound.
Trip recoveries of people with unilateral, transfemoral or knee disarticulation amputations: Initial findings

The purpose of this report is to provide novel findings from the kinematics of five amputees following a laboratory-induced trip. Only amputees with a unilateral, transfemoral or knee disarticulation amputation were included in this study. When the prosthesis was obstructed, all subjects used a lowering strategy, resulting in three harness-assisted recoveries and one fall. When the non-prosthetic limb was obstructed, one subject fell using an elevating strategy, one subject fell using a lowering strategy, and one subject, who was harness-assisted, used a hopping strategy. These results can be used to guide further studies of how to limit prosthetic knee flexion due to weight-bearing during a lowering strategy, implement compensatory step training to reduce fall risk, and identify appropriate, context-specific recovery strategies for people with transfemoral or knee disarticulation amputations.
Spatial memory in rats after 25 hours

We investigated the time course of spatial-memory decay in rats using an eight-arm radial maze. It is well established that performance remains high with retention intervals as long as 4 hr, but declines to chance with a 24-hr retention interval (e.g., Beatty & Shavalia, 1980b). It is possible that 24 hr reflects a genuine retention limitation of rat spatial memory. Alternatively, it may be possible to identify factors that might support memory performance even after very long delays. The current experiment was conducted to test the above two hypotheses. We evaluated performance using two intertrial intervals (24 and 48 hr) and two retention intervals (1 and 25 hr). Increasing the intertrial interval produced an approximately constant increase in performance for both retention intervals. This improvement is consistent with a trial-spacing effect (i.e., the superiority of spaced over massed trials). Rat spatial memory apparently lasts at least 25 hr.
Programmed cell death. V. Cytolytic enzymes in relation to the breakdown of the intersegmental muscles of silkmoths.

Abstract During the 3 week period of adult development cytolytic enzymes are synthesized and sequestered in lysosome-like particles in the intersegmental muscles of the silkmoth abdomen. A cathepsin begins to increase in titre during the first few days of adult development and continues to increase slowly during the first 2 weeks of this period. Then, during the final week of adult development, it increases at a logarithmic rate of about 30 per cent per day. In centrifuged homogenates prepared in sucrose, most of the enzymatic activity accompanies the mitochondrial ‘fraction’, from which a substantial proportion can be relased by osmotic shock or by detergents. In sucrose homogenates of degenerating muscle, a lesser fraction of the enzyme is sedimentable, and a greater percentage of the total enzymatic activity is ‘free’ prior to the addition of detergent. An acid phosphatase follows a similar pattern but is more readily solubilized by the homogenization procedure. These enzymes are considered to be directly responsible for the destruction of the intersegmental muscles.
New approaches for evaluating the quality of cancer pain management in the outpatient setting.

Abstract Both retrospective and prospective methods can be used to evaluate the quality of cancer pain management in the outpatient setting. Retrospective evaluations of the quality of cancer pain management in the outpatient setting provide benchmark data that can be used to change clinical practice for groups of patients or for specific types of cancer pain problems. Prospective evaluations of the quality of cancer pain management with patient diaries in the outpatient/home care setting can help clinicians do “real-time” evaluations and modify the pain management plan for individual patients. This report provides practical suggestions for evaluating the quality of cancer pain management in the outpatient setting. © 2001 by the American Society of Pain Management Nurses
Theory of multiharmonic generation and multiphoton electron emission at a metal surface.

The nonlinear-optical processes of multiharmonic generation and multiphoton electron emission at the surface of a metal are studied. Results are derived for arbitrary-order perturbation theory. Application is made to the Sommerfeld model, and estimates of the yields are given for simple free-electron-like metals.
Scanning-probe single-electron capacitance spectroscopy

The integration of low-temperature scanning-probe techniques and single-electron capacitance spectroscopy represents a powerful tool to study the electronic quantum structure of small systems - including individual atomic dopants in semiconductors. Here we present a capacitance-based method, known as Subsurface Charge Accumulation (SCA) imaging, which is capable of resolving single-electron charging while achieving sufficient spatial resolution to image individual atomic dopants. The use of a capacitance technique enables observation of subsurface features, such as dopants buried many nanometers beneath the surface of a semiconductor material1,2,3. In principle, this technique can be applied to any system to resolve electron motion below an insulating surface. As in other electric-field-sensitive scanned-probe techniques4, the lateral spatial resolution of the measurement depends in part on the radius of curvature of the probe tip. Using tips with a small radius of curvature can enable spatial resolution of a few tens of nanometers. This fine spatial resolution allows investigations of small numbers (down to one) of subsurface dopants1,2. The charge resolution depends greatly on the sensitivity of the charge detection circuitry; using high electron mobility transistors (HEMT) in such circuits at cryogenic temperatures enables a sensitivity of approximately 0.01 electrons/Hz½ at 0.3 K 5.
The origin of cornbelt maize: The isozyme evidence

Historical records show t hat the Midwestern dent corns of the United States originated from hybridization of two landraces, Northern Flint and Southern Dent. We examined the origin of Southern and Midwestern Dents by means of isozyme electrophoresis. Isozyme genotypes were determined for 23 loci in 12 plants each of 32 accessions of Southern Dent. Previously published isozyme data for maize landraces of Mexico and North America and for U.S. Midwestern Dents were included for comparative purposes. The data show that Northern Flint and Southern Dent are among the isozymically most divergent maize landraces. Nei’s genetic identities between populations of these two landraces are very low for conspecific populations (ca. 0.80). Southern Dent of the southeastern U.S. appears closely related to similar dent corns of southern Mexico, supporting a previously published hypothesis that U.S. Southern Dent is largely derived from the dent corns of southern Mexico. The Midwestern Dents, which resulted from crosses of Southern Dent and Northern Flint, are much more like Southern Dent than Northern Flint in their isozyme profile. Similarly, public inbreds show greater affinity to Southern Dent with the exception of sweet corn lines, which resemble Northern Flint in their isozyme allele frequencies. North American public inbreds do not contain appreciable isozymic variation beyond that found in Northern Flint and Southern Dent.
Slow evolution of transferrin and albumin in birds according to micro-complement fixation analysis

Rabbit antisera were prepared to purified ovotransferrin from chicken (order Galliformes) and red-winged blackbird (order Passeriformes) and to purified serum albumin from chicken and rhea (order Rheiformes). Quantitative microcomplement fixation was used to compare these proteins immunologically with those of representatives of all 27 orders of birds. The average interordinal immunological distances were 123 units for transferrin and 53 units for albumin.
Experimental Installation of 69-kV Synthetic-Insulated Underground Cables and Components

This paper describes the test installation, its operation, and the intermediate results of a continuous test program of synthetic-insulated 69-kV underground cables and joints, and terminations.
Variants at IRX4 as prostate cancer expression quantitative trait loci

Genome-wide association studies (GWAS) have identified numerous prostate cancer-associated risk loci. Some variants at these loci may be regulatory and influence expression of nearby genes. Such loci are known as cis-expression quantitative trait loci (cis-eQTL). As cis-eQTLs are highly tissue-specific, we asked if GWAS-identified prostate cancer risk loci are cis-eQTLs in human prostate tumor tissues. We investigated 50 prostate cancer samples for their genotype at 59 prostate cancer risk-associated single-nucleotide polymorphisms (SNPs) and performed cis-eQTL analysis of transcripts from paired primary tumors within two megabase windows. We tested 586 transcript–genotype associations, of which 27 were significant (false discovery rate ≤10%). An equivalent eQTL analysis of the same prostate cancer risk loci in lymphoblastoid cell lines did not result in any significant associations. The top-ranked cis-eQTL involved the IRX4 (Iroquois homeobox protein 4) transcript and rs12653946, tagged by rs10866528 in our study (P=4.91 × 10−5). Replication studies, linkage disequilibrium, and imputation analyses highlight population specificity at this locus. We independently validated IRX4 as a potential prostate cancer risk gene through cis-eQTL analysis of prostate cancer risk variants. Cis-eQTL analysis in relevant tissues, even with a small sample size, can be a powerful method to expedite functional follow-up of GWAS.
Environmental violence and crises of legitimacy in New Caledonia

Abstract This paper addresses the question of what factors besides resource abundance or scarcity play crucial roles in conditioning resource-related violent conflict, by investigating the responses of residents of villages near a mining project in New Caledonia to Rheebu Nuu, an indigenous environmental protest group. An overlooked and yet crucial factor in local support for Rheebu Nuu was a lack of faith in the government and, more fundamentally, in the democratic system through which representatives were elected. Instead, villagers put their faith in a revitalization of customary authority. Thus, environmental violence is not driven simply by resource abundance or scarcity; in this instance, it masked a crisis of political legitimacy, grounded in a history of opposition to the colonial power. This leads to the paper's second question: What constitutes a basis for political legitimacy, and how is this legitimacy – and its contestation – mediated by socio-cultural concerns? This study suggests that legitimacy requires the achievement of three elements: representation of people's interests, coherence with cultural identity, and popular acceptance of methods used to exert power. The protest group was more successful at achieving these elements of legitimacy, and thus the support of the local residents, than was either the government or the mining company. However, not all community members felt that Rheebu Nuu indeed had the support of customary authority, and many disagreed with the group's violent tactics. Thus, protest groups may be subject to the same criteria of legitimacy as the governments or other bodies that they oppose.
Orientational Order in Solid Ortho-Hydrogen. II. Hexagonal Close-Packed Molecular Lattice

The orientational ordering of the molecules in solid hcp ortho-${\mathrm{H}}_{2}$ is studied theoretically, using the internal-field approximation and neglecting lattice vibrations. A relaxation method suitable for use with a high-speed computer is employed in a search for molecular orderings that might occur in stable or metastable phases; numerical characterizations of the molecular states and the thermodynamic properties of these phases are then obtained for appropriate ranges of temperature. Orders describable in terms of four or eight sublattices are studied. On the assumption that there is quadrupole-quadrupole coupling only between nearest-neighbor molecules, it is concluded that as $T$ arises the phase (space group $\mathrm{Pca}{2}_{1}$) stable at the lowest temperatures undergoes a first-order transition into a $\frac{P{2}_{1}}{c}$ phase, followed by second-order transitions into a $\mathrm{Pnma}$ phase and then into an orientationally disordered phase. A model that includes quadrupole-quadrupole couplings between all molecules shows a first-order transition from the $\mathrm{Pca}{2}_{1}$ phase into a $\frac{P{6}_{3}}{m}$ phase, followed by a second-order transition into the orientationally disordered phase. It is concluded that the "$\ensuremath{\lambda}$ transition" in pure ortho-${\mathrm{H}}_{2}$ and in ortho-para mixtures sufficiently rich in ortho-${\mathrm{H}}_{2}$ will consist of a first-order transition from an orientationally ordered phase with fcc lattice ($\mathrm{Pa}3$) to an orientationally ordered phase with hcp lattice, followed by orientational transitions on the hcp lattice that give rise to the finer structure in the specific-heat curve observed by Ahlers and Orttung. In the case of solid deuterium rich in para-${\mathrm{D}}_{2}$, one can expect the transition to be a simple one from the orientationally ordered fcc phase to an orientationally disordered hcp phase, with no fine structure in the specific-heat curve.
Pyloric deformation from peptic disease. Radiographic evidence for incompetence rather than obstruction.

We have used double-contrast radiographic techniques to clarify what changes in the configuration and movements of the gastroduodenal junction result when peptic lesions involve the distal gastric segment between the proximal (PPL) and the distal pyloric muscle loop (DPL). Among 50 cases of pyloric ulceration diagnosed during a four-year study period, 18 cases fulfilled all study criteria. Ulcers maintained a consistent location with regard to the muscular structures of the pylorus, and by affecting these structures, led to many strange deformations of the gastric outlet including permanent pseudodiverticula and reversal of pyloric angulation. The most common site for peptic lesions in the pyloric segment was the protuberance of the lesser curvature called the pyloric torus; many torus lesions extended into and destroyed the DPL. This led to widening of the gastric outlet and radiographic evidence of increased duodenogastric reflux. Pyloric closure was further impaired in this setting because the mucosa no longer prolapsed into the gastric outlet and did not occlude the pyloric lumen as it normally does. Less common lesions involved the greater curvature and the PPL. In one patient, scarring of the PPL led to an antrat web and gastric hyperperistalsis. This was the only patient who required operation for chronic gastric outlet obstruction. One-third of the 18 patients had reflux esophagitis in addition to peptic pyloric disease. In most patients without additional ulcerogenic risk factors, treatment with antisecretory agents led to the healing of ulcer craters. We conclude that the morphologic and functional changes of the gastric outlet caused by peptic lesions depend, in part, on the effect the ulcer has on the underlying pyloric musculature. We also propose that pyloric incompetence (and hence possibly dumping and bile reflux gastritis) may be a more common complication of pyloric ulceration than hitherto appreciated.
Origin of the intermediate damping peak in microlayer composites

A comparison of glass transition temperatures measured by differential scaning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) was made using mi9crolayer composites with many alternating layers of two polymers. What appeared to be a third transition at a temperature intermediate between the glass transitions of the two components was observ ed in DMTA but not DSC. The mechanical orgin of this intermediate damping peak in the layered composites was established. The viscoelastic properties of each polymer were modelled by a spring and dashpot in series, and the composite as a parallel arrangement of two Maxwell elements. It was shown that an anomalous damping peak can appear between the glass transition temperatures when the modulus of the composite can not drop below the modulus of the glassy layers, although the viscosity of the composite continues to be defined by the viscosity of the rubbery layers in this temperature range. The intermediate damping peak may be a general feature in the dynamic mechanical behavior of co-continuous multiphase systems including polymer blends and continuous fiber composites.
Vegetation response to disturbance in a coastal marsh in Texas

Disturbance is considered one of the main factors influencing plant species composition and diversity. We conducted a field study to address the plant community response in a coastal marsh to a major disturbance. In 1992, muskrats (Ondatra zibethicus L.) completely removed vegetation within a 450 ha area of intermediate coastal marsh in Texas, USA. We used vegetation data collected prior to the disturbance (1989-1991) as a baseline for comparison to that recorded annually for a decade (1992-2002) following the disturbance. We compared species diversity, richness, relative abundance, evenness, and species similarity between pre and postdisturbance periods to evaluate the temporal response of the disturbed plant community. Plant diversity in the study area returned to predisturbance levels after 10 years. Species diversity in the study area had two peaks following the main disturbance. These peaks are associated with fluctuations of the water levels in the area. Our results suggest that it is possible to control the sedge or grass dominance in a community by subjecting the area to a carefully timed willful disturbance (e.g., grazing or fluctuating water levels) to achieve management goals. However, vegetation composition in the area changed from a grass-dominated (predisturbance) to sedge-dominated (postdisturbance) community. At the conclusion of sampling in 2002, plant species abundance, evenness, dominance, and richness conditions reached levels similar to predisturbance. However, the species composition after a decade postdisturbance differed from that during the predisturbance period. Therefore, even though we are able to predict the return of species diversity, evenness, and richness of a community after a period following disturbance, the actual species composition of an intermediate marsh following recovery is difficult to determine accurately, as it is contingent on several biotic and abiotic conditions that prevail while the system recovers from disturbance.
The 4-oxalocrotonate tautomerase family of enzymes: How nature makes new enzymes using a β-α-β structural motif

4-Oxalocrotonate tautomerase (4-OT) catalyzes the isomerization of beta,gamma-unsaturated enones to their alpha,beta-isomers. The enzyme is part of a plasmid-encoded pathway, which enables bacteria harboring the plasmid to use various aromatic hydrocarbons as their sole sources of carbon and energy. Among isomerases and enzymes in general, 4-OT is unusual for two reasons: it has one of the smallest known monomer sizes (62 amino acids) and the amino-terminal proline functions as the catalytic base. In addition to Pro-1, three other residues (Arg-11, Arg-39, and Phe-50) have been identified as critical catalytic residues by kinetic analysis, site-directed mutagenesis, chemical synthesis, NMR, and crystallographic studies. Arginine-39 functions as the general acid catalyst (assisted by an ordered water molecule) in the reaction while Arg-11 plays a role in substrate binding and facilitates catalysis by acting as an electron sink. Finally, the hydrophobic nature of the active site, which lowers the pK(a) of Pro-1 to approximately 6.4 and provides a favorable environment for catalysis, is largely maintained by Phe-50. 4-OT is also the title enzyme of the 4-OT family of enzymes. The chromosomal homologues in this family are composed of monomers ranging in size from 61 to 79 amino acids, which code a beta-alpha-beta structural motif. The homologues all retain Pro-1 and generally have an aromatic or hydrophobic amino acid at the Phe-50 position. Characterization of representative members has uncovered mechanistic and structural diversity. A new activity, a trans-3-chloroacrylic acid dehalogenase, has been identified in addition to the previously known tautomerase and isomerase activities. Two new structures have also been found, along with the 4-OT hexamer. The dehalogenase functions as a heterohexamer while the Escherichia coli homologue, designated YdcE, functions as a dimer. Moreover, both 4-OT and the Bacillus subtilis homologue, designated YwhB, exhibit low-level dehalogenase activity. Amplification of this activity could have produced the full-fledged dehalogenase. The sum of these observations indicates that Nature uses the beta-alpha-beta structural motif as a building block in a variety of manners to create new enzymes.
MINERAL COMPOSITION OF CHLOROTIC ORANGE LEAVES AND SOME OBSERVATIONS ON THE RELATION OF SAMPLE PREPARATION TECHNIQUE TO THE INTERPRETATION OF RESULTS.

sential mineral elements. Agreement does not always exist, however, as to whether a specific type of leaf-symptom pattern is related to total content of the deficient element or only to a specific fraction of it. This is particularly true of the presumed deficiencies of iron and zinc where sample selection, contamination, and poor precision of analytical procedures are all complicating factors. An extensive review of all previous work is beyond the scope of this report. Jacobson (8) and Lindner and H arle ? (10) point out some of the more pertinent discrepancies with respect to iron content and iron chlorosis. More recently McGeorge (11) reports the lack of any apparent relationship between total Fe or Zn and the appearance of the specific deficiency symptoms for these elements in citrus, pear, and several other plants. Other studies have occasionally shown this same result in the case of Fe; but Jacobson (8) found that surface contamination was a factor of major importance in producing discrepant results. When pear leaves from trees grown in calcareous soil were carefully washed in dilute HC1, a c'orrelation was found between the low total Fe values found and the iron chlorosis shown. Bennett (1) confirmed this observation with further studies, although he found a stronger relationship of chlorosis to an acid-soluble, or "active'' Fe fraction than to the total. In Florida (?), New Zealand (7), and elsewhere citrus trees showing typical zinc deficiency symptoms have been found to contain less total zinc in their leaves than leaves from healthy trees. In Florida when the acidity of the topsoil of the Lakeland and related series drops below pH 5.0 (between 4.5 and 5.0) for a considerable length of time, citrus trees may become unthrifty in appearance, sparsely foliated, and show typical iron-chlorosis leaf patterns. This interveinal chlorosis condition strongly resembles the lime-induced iron chlorosis pattern (2) and that associated with poor drainage. Exploratory tests in small containers showed that reducing the acidity by treatment with the carbonates of Ca, Na, or ? (or extracting the soil with NH4-acetate) all resulted in the disappearance of this symptom in young citrus seedlings. In connection with this general problem, some analyses were made to determine the mineral composition of leaves from trees affected with this type of chloro-
On a certain mixed variational theorem and a proposed application

Formulation d'une equation variationnelle pour les deplacements et certaines contraintes en vue d'une application aux plaques elastiques stratifiees isotropes et anisotropes
Role of iron in alcoholic liver disease: introduction and summary of the symposium

Abstract The National Institute on Alcohol Abuse and Alcoholism and the Office of Dietary Supplements, National Institutes of Health, sponsored a symposium on the “Role of Iron in Alcoholic Liver Disease” at Bethesda, Maryland, USA, October 2002. Alcoholic liver disease is a major cause of illness and death in the United States. Oxidative stress plays a key role in the pathogenesis of alcoholic liver disease. Iron can induce oxidative stress by catalyzing the conversion of superoxide and hydrogen peroxide to more potent oxidants such as hydroxyl radicals, which can cause tissue injury by initiating lipid peroxidation and causing oxidation of proteins and nucleic acids. Increasing evidence supports the suggestion that iron plays a significant role in the pathogenesis of alcoholic liver disease by exacerbating oxidative stress. Understanding the underlying mechanisms by which iron participates in the initiation and development of alcoholic liver disease may help design strategies for the treatment and prevention of the disease. For this symposium, nine speakers were invited to address the following issues: (1) iron intake from foods and dietary supplements; (2) hepatic iron overload in alcoholic liver disease; (3) iron-dependent activation of nuclear factor-kappa B (NF-κB) in Kupffer cells; (4) iron and cytochrome P450 2E1 (CYP2E1)–dependent oxidative stress and liver toxicity; (5) iron-induced oxidative stress in alcoholic hepatic fibrogenesis; (6) hemochromatosis and alcoholic liver disease; (7) iron as a co-morbid factor in nonhemochromatotic liver diseases; (8) iron and liver cancer; and (9) iron chelators and iron toxicity. On the basis of these presentations, it is concluded that heavy alcohol intake can result in increased accumulation of iron in the liver, in both hepatocytes and Kupffer cells. Iron-induced oxidative stress may promote the severity of alcoholic liver disease by (1) inducing NF-κB activation and subsequently increasing transcription of proinflammatory cytokines in Kupffer cells; (2) exacerbating CYP2E1-induced oxidative stress, especially in hepatocytes, through production of more toxic hydroxyl radicals; (3) stimulating hepatic stellate cells to produce excess amount of collagen and other matrix proteins that can lead to fibrosis; and (4) causing DNA damage and mutations that promote the development of liver cancer. Dietary iron supplements may further exacerbate the severity of alcoholic liver disease by increasing the magnitude of oxidative stress. We hope that the studies presented will stimulate further research in this exciting area.
Antihyperalgesic effects of the muscarinic receptor ligand vedaclidine in models involving central sensitization in rats

Abstract It is well established that muscarinic cholinergic agonists produce antinociceptive effects in a number of acute pain models. However, relatively little is known about the effects of muscarinic receptor agonists in models which involve central sensitization in pain pathways. The purpose of the present studies was to evaluate the effects of vedaclidine, a muscarinic receptor mixed agonist/antagonist across receptor subtypes, in models involving central sensitization. Vedaclidine (0.3–10 mg/kg s.c.) produced dose-related antihyperalgesic effects in the formalin test as well as a dose-related reversal of capsaicin-induced mechanical hyperalgesia in rats. In the carrageenan test, vedaclidine (0.1–30 mg/kg) produced a dose-related reversal of both mechanical and thermal hyperalgesia that were antagonized by the muscarinic receptor antagonist scopolamine. In addition, the antihyperalgesic effects of vedaclidine in the carrageenan test were synergistic with the antihyperalgesic effects of the non-steroidal antiinflammatory drug ketoprofen, as demonstrated by isobolographic analysis. The present studies demonstrate that vedaclidine produces antihyperalgesic effects in models involving central sensitization, suggesting that vedaclidine, and potentially other muscarinic receptor agonists, may have clinical utility in the management of pain states involving central sensitization, such as neuropathic and inflammatory pain states.
The mechanism of methoxy radical oxidation: hydrogen abstraction versus trioxy radical formation

Abstract The energetic profiles of the two possible pathways of formaldehyde and HO2 radical formation in the oxidation of the methoxy radical CH3O, i.e. (a) via H-abstraction or (b) as addition/elimination involving methyl trioxy radicals CH3OOO as intermediates, were calculated using G2M(RCC) and CBS-QCI/APNO model chemistries. The 298 K barrier height for path (a) is found to be 11.5 (14.8) kcal/mol at G2M(RCC) level (CBS-QCI/APNO value in parentheses). Along path (b), the HO2 elimination from cis-CH3OOO is found to have a barrier of 1.3 (8.5) kcal/mol. Therefore, oxidation of CH3O is likely to occur by forming the CH3OOO intermediate rather than by H-abstraction.
Bromine oxidation in a highly selective EDTA titration of thallium

Abstract A comparative study of various oxidizing agents for oxidation of thallium (I) to thallium (III) has been made. Aqua regia oxidation gives slightly low results and requires careful treatment. The proposed bromine oxidation not only gives complete oxidation but also offers many other advantages of accuracy, simplicity, and rapidity. The effective oxidation is made possible due to the presence of excess bromine and stabilization of thallic ion by complex formation. An oxidation-resistant dye (PAR or PAN) should be used as indicator in the EDTA titration of thallium (III). Since the thallium (III)-EDTA complex is easily reduced, thallium and other metals may be titrated stepwise in the same solution. The proposed method has been successfully applied to the analysis of lead-thallium alloys.
Knowledge-Assisted Retrieval of Online Product Information in Architectural/Engineering/Construction

With a better understanding about the product market, industry practitioners can make more informed decisions for product specification, selection, and procurement. However, current approaches that support Architectural/Engineering/Construction (A/E/C) information acquisition do not provide a comprehensive market scan. While the Internet provides an ever-growing resource for product information, existing approaches have limited capabilities to make use of this virtual market. Therefore, the writers have developed a knowledge-assisted approach to specifically address the potential of the virtual market—help retrieve A/E/C product information, particularly information about different manufacturers, from the Internet. The paper introduces the building blocks of the developed approach, which includes domain knowledge utilization, information retrieval (IR) techniques, and strategies that incorporate domain knowledge into knowledge-supported IR approaches. Specifically, domain knowledge represented in the form...
Competitive hydrolytic and elimination mechanisms in the urease catalyzed decomposition of urea.

We present a high-level quantum chemical study of possible elimination reaction mechanisms associated with the catalytic decomposition of urea at the binuclear nickel active site cluster of urease. Stable intermediates and transition state structures have been identified along several possible reaction pathways. The computed results are compared with those reported by Suarez et al. for the hydrolytic catalyzed decomposition. On the basis of these comparative studies, we propose a monodentate coordination of urea in the active site from which both the elimination and hydrolytic pathways can decompose urea into CO2 and NH3. This observation is counter to what has been experimentally suggested based on the exogenous observation of carbamic acid (the reaction product from the hydrolysis pathway). However, this does not address what has occurred at the active site of urease prior to product release. On the basis of our computed results, the observation that urea prefers the elimination channel in aqueous solut...
Are College Students More Disturbed Today? Stability in the Acuity and Qualitative Character of Psychopathology of College Counseling Center Clients: 1992-1993 Through 2001-2002

Are clients at college counseling centers more disturbed today than they were 5, 10, or 20 years ago? Since the mid-1980s, counseling center personnel have consistently perceived student clients as more distressed or reported acutely distressed clients as more prevalent than they did 1, 3, or 5 years ago. Only 3 studies employing a systematic, data-based methodology have addressed this question. Two researchers used different actuarial measures of the acuity or character of client pathology and concluded that current student clients are not more disturbed than were earlier ones. One researcher used clinical judgments rendered at the end of therapy and concluded that current students were more distressed. Using the Personality Assessment Inventory, the author found the actuarially determined quantitative and qualitative indices of pathology unchanged for 3,400 counseling center clients seen during 10 consecutive years. Over the same period, the use of medications increased fivefold. An actuarial measure of client distress appears crucial to both accurate diagnosis and treatment and to the adequate preparation of future counseling center professionals.
Security of supply in the Western European market for natural gas

Abstract Western European natural gas supplies are subject to the risk of politically motivated supply disruptions. Risks cannot be avoided, but their dangers can be reduced through prudent diversification policies. This paper describes a model that is simple enough so that others may employ it to test out alternative numerical assumptions related to the security of supplies. The analysis is based upon three key ideas: insecure sources provide benefits during normal periods; they impose costs during disruption periods; and the risks of disruption may be described in terms of quantitative (but subjectively determined) probabilities. Charts are provided so that the reader may draw independent conclusions based on alternative values of these three factors.