cssi/SciSciGPT-SciSciNet huggingface dataset:
Loss of ergodicity in a quantum hopping model of a dense many body system with repulsive interactions

Abstract In this work we report on a loss of ergodicity in a simple hopping model, motivated by the Hubbard Hamiltonian, of a many body quantum system at zero temperature, quantized in Euclidean time. We show that this quantum system may lose ergodicity at high densities on a large lattice, as a result of both Pauli exclusion and strong Coulomb repulsion. In particular we study particle hopping susceptibilities and the tendency towards particle localization. It is found that the appearance and existence of quantum phase transitions in this model, in the case of high density and strong Coulomb repulsion, depends on the starting configuration of particle trajectories in the numerical simulation. We argue that this breakdown may be the Euclidean time version of a breakdown of the eigenstate thermalization hypothesis in real time quantization.
Temporal pattern and synergy influence activity of ERK signaling pathways during L-LTP induction

Long lasting long-term potentiation (L-LTP) is a cellular mechanism of learning and memory storage. Studies have demonstrated a requirement for the extracellular signal-regulated kinase (ERK) activation in L-LTP produced by a diversity of temporal stimulation patterns. Multiple signaling pathways converge to activate ERK, with different pathways being required for different stimulation patterns. We addressed the critical questions of whether maximal activation of ERK requires multiple pathways, and whether different temporal patterns select different signaling pathways for ERK activation. We developed a computational model of five signaling pathways (including two novel pathways) leading to ERK activation during L-LTP. Simulations show that calcium and cAMP work synergistically to activate ERK, and that stimuli given with large inter-trial intervals activate more ERK than shorter intervals, a temporal sensitivity similar to PKA but contrary to CaMKII. These results suggest that signaling pathways with different temporal sensitivity facilitate ERK activation to diversity of temporal patterns.
Inclusion of Individuals with Disabilities

The need to develop an environment that is fully inclusive of individuals with disabilities is legally and morally compelling. Full inclusion of individuals with disabilities in the workforce generally—and in statistics specifically—benefits not just individuals with disabilities, but everyone in the workforce and in the field.
Daily Parent-Adolescent Digital Exchanges

The present study tracked adolescents via mobile phones to describe how parents and their adolescent children are using digital technologies in daily life (i.e. facilitating warmth and behavioral control), and whether these uses are associated with the quality of offline parent-adolescent interactions and with adolescents’ mental health. A sample of young adolescents (N = 388; mean age 13.37) completed a 14-day ecological momentary assessment in 2016- 2017, reporting on their daily digital contact and offline interactions with their parents and their mental health. Adolescents reported using texting and calling to communicate somewhat infrequently with their parents (i.e., on 29% of days), but days with more digital contacts (for both warmth and behavioral control) were also more likely to be characterized by more positive offline interactions with parents. Furthermore, adolescents struggling with mental health symptoms across the study period reported using texts/calls more frequently to seek out parent support, and parents were more likely to do text/call “check ins” on young people who were experiencing more behavioral problems. Results highlight the potential for digital communication devices to be used as tools in fostering parent-adolescent connection, support provision, and behavioral control in the digital era.
Competencies and behaviors observed when students solve geometry proof problems: an interview study with smartpen technology

Decades of research have established that solving geometry proof problems is a challenging endeavor for many students. Consequently, researchers have called for investigations that explore which aspects of proving in geometry are difficult and why this is the case. Here, results from a set of 20 interviews with students who were taught proof in school geometry are reported. Students who earned A or B course-grades in the proof unit(s) were asked to share their thinking aloud while solving two proof tasks using smartpens. Student thinking was analyzed for two subgroups—students who were successful with both proofs (n = 7) and who were unsuccessful with both proofs (n = 13). Large differences were observed in how often students in the two groups exhibited certain competencies and behaviors. The largest gaps occurred in the ways in which students attended to the proof assumptions, attended to warrants in their proofs, and demonstrated logical reasoning.
Exponential Smoothing Forecast of African Americans' COVID-19 Fatalities

This work focuses on the spread and impact of COVID-19 in the black community. A detailed analysis will improve the universality of a comprehensive mitigation strategy in reducing and combatting the spread of coronavirus. Our analysis of COVID-19 spans March 2020 to November 2020. Forecasting computation was based on exponential smoothing. The quality of our models was evaluated using the Mean Absolute Percentage Error. Predominantly black states in the US were considered for the experiment. All things being equal, a forecast to February 2021 suggests a disturbing forecast for the African American communities in the states investigated.
Improving pediatric patient engagement, outcomes, and satisfaction via an interactive perioperative teaching platform.

Patient satisfaction is an important quality endpoint in perioperative care.1 For pediatric patients, previous work has described improving family education and reducing anxiety using visual information.2 In this prospective randomized study, we assessed whether adding an interactive, web-based perioperative teaching platform (IPTP) to conventional pre-operative education would improve caregiver satisfaction and comprehension of the perioperative process, while reducing anxiety.
Bracketing Compound Nouns for Logic Form Derivation

We present here a method for bracketing coordinated compound nouns in the larger context of deriving first order logic forms. The method consists of two phases: (1) detection - extract candidate compound nouns from a parse tree and (2) interpretation - provide a bracketing solution for each candidate. Bracketing performance on 525 coordinations is 87.42%. This compares favorably with a 52.35% baseline when a default split by the coordination is applied.
Mach, Einstein, and the Search for Reality

In the history of ideas of our century, there is a chapter that might be entitled ‘The Philosophical Pilgrimage of Albert Einstein’, a pilgrimage from a philosophy of science in which sensationism and empiricism were at the center, to one in which the basis was a rational realism. This essay,* a portion of a more extensive study1, is concerned with Einstein’s gradual philosophical reorientation, particularly as it has become discernible during the work on his largely unpublished scientific correspondence.2
A Comparative Study of Some Staining Properties of Crystals in a Lympho-plasmocytoid Cell, of Russell Bodies in Plasmocytes, and of Amyloids-With Special Emphasis on Their Isoelectric Points

A staining procedure for determining the approximate isoelectric points of substances has been applied to tissue sections containing (a) intracytoplasmic crystals in a lympho-plasmocytoid cell, (b) Russell bodies of plasmocytes, and (c) secondary and primary amyloids. The same method was also applied to sections of human gamma globulin. The results indicate the similarity of Russell bodies, the crystals, and gamma globulin, all of which showed an isoelectric range between pH 6 and 7.5. Other staining methods employed tended to confirm this identity. The discrepancies reported in the literature on the staining properties of Russell bodies are discussed. All of the amyloids tested had an apparent isoelectric point near pH 5. Various suggestions in the literature about the nature and origin of amyloid are summarized.
Sex, illness, and medical care: A review of data, theory, and method

Abstract This paper is a review of data concerning the sex differences in mortality, morbidity, and use of health services that are currently to be found among the countries of Europe and North America. In all developed countries, male mortality rates are higher than the rates of females, but in all countries for which data are available, women report more acute illness than men and make greater use of health services. There are systematic variations in this overall pattern of sex differences, however, by cause of death and disease, by age, and by marital status. In addition to summarizing these data, the paper also examines them from a methodological as well as a theoretical perspective. Observed sex differences in health status are largely social and psychological in origin. Advances in the understanding and interpretation of these differences will require a higher level of sustained attention from social scientists than has been exhibited in the past.
Women in Human Services Management

(1999). Women in Human Services Management. Administration in Social Work: Vol. 23, No. 2, pp. 17-31.
Isotopic Labeling of Embryo, Yolk Sac, and Intracellular Parasites of the Embryonated Hen's Egg by Yolk Replacement

A technique is described which allows the replacement of 50% of the yolk of the embryonated hen's egg with large volumes of diverse but chemically defined solutions. By using an electrosurgical unit and a polyethylene tunnel, the procedure was performed on eggs from days 3 through 7 with greater than 90% surgical success and viability for the short term. More than 50% of the eggs replaced showed viability for 2 weeks, and a significant proportion went full term. (32)PO(4) and amino acids ((3)H and (14)C) added to the replaced eggs were incorporated into the macromolecules of the embryo and yolk sac as well as into parasitic rickettsiae cultivated in the replaced eggs. The incorporated (32)PO(4) was shown to be assimilated into a variety of biochemical species.
Fly LMBR1/LIMR-type protein Lilipod promotes germ-line stem cell self-renewal by enhancing BMP signaling

Limb development membrane protein-1 (LMBR1)/lipocalin-interacting membrane receptor (LIMR)-type proteins are putative nine-transmembrane receptors that are evolutionarily conserved across metazoans. However, their biological function is unknown. Here, we show that the fly family member Lilipod (Lili) is required for germ-line stem cell (GSC) self-renewal in the Drosophila ovary where it enhances bone morphogenetic protein (BMP) signaling. lili mutant GSCs are lost through differentiation, and display reduced levels of the Dpp transducer pMad and precocious activation of the master differentiation factor bam. Conversely, overexpressed Lili induces supernumerary pMad-positive bamP-GFP-negative GSCs. Interestingly, differentiation of lili mutant GSCs is bam-dependent; however, its effect on pMad is not. Thus, although it promotes stem cell self-renewal by repressing a bam-dependent process, Lilipod enhances transduction of the Dpp signal independently of its suppression of differentiation. In addition, because Lili is still required by a ligand-independent BMP receptor, its function likely occurs between receptor activation and pMad phosphorylation within the signaling cascade. This first, to our knowledge, in vivo characterization of a LMBR1/LIMR-type protein in a genetic model reveals an important role in modulating BMP signaling during the asymmetric division of an adult stem cell population and in other BMP signaling contexts.
Synthesis of α,β-Deuterated 15N Amino Acids Using a Coupled Glutamate Dehydrogenase-Branched-Chain Amino Acid Aminotransferase System

Abstract Gram amounts of various 15 N-enriched L-amino acids have been synthesized using a coupled enzymatic system. Catalytic amounts of 15 N-labeled L-glutamate are generated using ( 15 NH 4 ) 2 SO 4 , α-ketoglutarate, and glutamate dehydrogenase. The labeled glutamate in turn serves as an amine donor to an appropriate α-keto acid using the Escherichia coli branched-chain amino acid aminotransferase, the subcloning and overexpression of which is described. In order to drive the reaction to completion the redox cofactor NADPH is regenerated using a glucose dehydrogenase system. Since the aminotransferase catalyzes exchange of the α-hydrogen, carrying out this reaction in 2 H 2 O gives rise to 2- 2 H,2- 15 N-labeled amino acids. Deuteration can be readily extended to the β position as well by preexchanging the α-keto acids in basic 2 H 2 O. The isotopically labeled amino acids are recovered in yields of 70-80%.
Docosahexaenoic Acid and Arachidonic Acid Prevent Essential Fatty Acid Deficiency and Hepatic Steatosis

Objectives Essential fatty acids are important for growth, development, and physiologic function. α-Linolenic acid and linoleic acid are the precursors of docosahexaenoic and arachidonic acid, respectively, and have traditionally been considered the essential fatty acids. However, the authors hypothesized that docosahexaenoic acid and arachidonic acid can function as the essential fatty acids. Methods Using a murine model of essential fatty acid deficiency and consequent hepatic steatosis, the authors provided mice with varying amounts of docosahexaenoic and arachidonic acids to determine whether exclusive supplementation of docosahexaenoic and arachidonic acids could prevent essential fatty acid deficiency and inhibit or attenuate hepatic steatosis. Results Mice supplemented with docosahexaenoic and arachidonic acids at 2.1% or 4.2% of their calories for 19 days had normal liver histology and no biochemical evidence of essential fatty acid deficiency, which persisted when observed after 9 weeks. Conclusion Supplementation of sufficient amounts of docosahexaenoic and arachidonic acids alone without α-linolenic and linoleic acids meets essential fatty acid requirements and prevents hepatic steatosis in a murine model.
Architecture of an expert-system-based code-compliance checker

Abstract This paper reports the development of an expert-system-based code-checking framework which ‘certifies’ compliance of a design with appropriate code provisions. As a ‘test-bed’ for this prototype, reinforced concrete design compliance with most of the ACI-318 code provisions (found in Chapters 8 to 12 of Reference 1) is selected. A comprehensive and user-friendly framework is developed through various modules. First initial data entry is performed either interactively during the consultation, or through a spreadsheet (Lotus 123) input. Then consultation with the knowledge based expert system is greatly enhanced by a powerful user interface with such capabilities as: arbitrary provision checking, display of code provision, and editing of input data. Finally a report summarizing the consultation (including the original input data, tabulation of the most relevant internally-computed variables, and list of code provisions which are either satisfied or violated) is generated. The knowledge base development resulted in both a critical evaluation of the code, and the generation of an exhaustive tree representation of the rules and design variables. It was found that this initial prototype could be of practical engineering relevance, that its architecture could be adopted for applications other than the one used, and finally that it could serve as an initial configuration for a quality assurance program for design in general.
Reaction and XRD studies on Cu based methanol decomposition catalysts: Role of constituents and development of high-activity multicomponent catalysts

Abstract A series of Cu based catalysts with and without ZnO have been studied for methanol decomposition in the absence of water. CO and H2 are the major products. A significant amount of methyl formate is produced at low conversions and low reaction temperatures. Cu ZnO based catalysts show high initial activity but quickly deactivate. This may be attributed to the dissolution of Zn into the Cu lattice. Without the component ZnO, other Cu based catalysts show good activity and better stability. Cr increases the stability of the Cu based catalysts but slightly reduces the selectivity to CO. The composition of Cr correlates with the yield of dimethyl ether. Among many other components evaluated, a small amount of Ba, Mn and Si oxides strongly promote the Cu based catalysts in methanol decomposition. Cu, Cr, Si, O and Ba or Mn constitute the components of the highly active multicomponent catalyst. Characterizations of the catalysts combined with the compositional study suggest that metallic Cu is the active species for methanol decomposition. Silica enhances the activity probably by increasing the dispersion of Cu.
Phosphatidylkojibiosyl diglyceride: Metabolism and function as an anchor in bacterial cell membranes

The recently discovered phosphoglycolipid, phosphatidylkojibiosyl diglyceride (PKD), was first observed as a biosynthetic by-product of glucosyl diglyceride metabolism inStreptococcus faecalis (faecium) ATCC 9790. Its structure is 1,2-diacyl-3-O(2′-O-α-D-glucopyranosyl-6′-O-phosphoryl-[1″,2″-diacyl-3″-O-sn-glycerol]-α-D-glucopyranosyl)-sn-glycerol. The biosynthesis of phosphatidylkojibiosyl diglyceride occurs by a novel transphosphatidylation reaction in which a phosphatidyl group is transferred from diphosphatidyl glycerol to the primary alcohol function at the 6 position of the internal glucose of kojibiosyl diglyceride. The reaction is catalyzed by a membrane-derived enzyme. Phosphatidylkojibiosyl diglyceride is bound covalently through a phosphodiester bond to the polyglycerol phosphate moiety of membrane lipoteichoic acid fromS. faecalis. Phosphatidylkojibosyl diglyceride has four nonpolar long chain fatty acyl groups and appears to have the necessary physico-chemical properties to anchor the long hydrophilic glycerol phosphate polymer of lipoteichoic acid to the hydrophobic environment of the membrane ofS. faecalis and probably other gram-positive bacteria as well.
Aberrant innate immune responses in TLR-ligand activated HLA-B27 transgenic rat cells.

Background: Commensal enteric microbiota initiate and perpetuate immune-mediated colitis in HLA-B27 transgenic (TG) rats but not wildtype (non-TG) littermates. However, the role of the innate immune response to bacterial components has not been established. Methods: We examined responses induced by bacterial adjuvants through Toll-like receptor (TLR) and NOD2 signaling in T-cell-depleted splenocytes from HLA-B27 TG rats versus non-TG controls. Results: We found that various bacterial adjuvants induced TNF production by cells obtained from specific pathogen-free (SPF) and germ-free (GF, sterile) TG and non-TG rats. Peptidoglycan-polysaccharide (PG-PS), lipopolysaccharide (LPS), and CpG DNA motifs stimulated higher levels of TNF production by SPF TG rat spleen cells compared to non-TG cells. CD11b/c cell depletion eliminated PG-PS and LPS-induced TNF and dramatically reduced CpG-stimulated TNF production. Both SPF and GF TG rat spleens contain more cells that express high levels of CD11b/c and show enhanced mRNA expression of TLR-2 and TLR-4 compared to non-TG rat spleens. In contrast, constitutive and bacterial-induced IL-10 production was markedly lower in TG cells compared to non-TG cells of rats from the same SPF or GF housing conditions. Notably, the ratio of TNF to IL-10 produced after TLR ligand activation was significantly higher in TG than non-TG cells. Conclusions: HLA-B27 TG rats have an aberrant cell composition, altered functional TLR expression, and an intrinsic defect in IL-10 production in response to TLR ligands, which may result in exaggerated proinflammatory responses to commensal enteric bacteria and uncontrolled inflammation in this colitis model. (Inflamm Bowel Dis 2008)
Direct recovery of three-dimensional scene geometry from binocular stereo disparity

An analysis of disparity is presented. It makes explicit the geometric relations between a stereo disparity field and a differentially project scene. These results show how it is possible to recover three-dimensional surface geometry through first-order (i.e., distance and orientation of a surface relative to an observer) and binocular viewing parameters in a direct fashion from stereo disparity. As applications of the analysis, algorithms have been developed for recovering three-dimensional surface orientation and discontinuities from stereo disparity. The results of applying these algorithms to natural image binocular stereo disparity information are presented. >
Devil's staircase and disordering transitions in sliding vortices and Wigner crystals on random substrates with transverse driving

Using numerical simulations we show that, in the presence of random quenched disorder, sliding superconducting vortices and Wigner crystals pass through a variety of dynamical phases when an additional transverse driving force is applied. If the disorder is weak, the driven particles form a moving lattice and the transverse response shows a devil's staircase structure as the net driving force vector locks with the symmetry directions of the moving lattice, in agreement with the predictions of Le Doussal and Giamarchi. For strong disorder, and particularly for smoothly varying potential landscapes, the transverse response consists of a sequence of disordering transitions with an intervening formation of stable channel structures.
A new method for coating microspheres with zirconium carbide and zirconium carbide-carbon graded coats

Abstract A new method for the chemical vapor deposition of ZrC and C-ZrC alloys has been developed. This process has been applied to the fabrication of coated particle nuclear fuels of the type used in the large High Temperature Gas-Cooled Reactor. A powder feeder is used to supply ZrCl 4 to the fluidized bed coating furnace where it undergoes reaction with a hydrocarbon to form ZrC. Quantitative metering of the ZrCl 4 makes it possible to control the deposition of the ZrC and the codeposition of the C-ZrC alloys on the fuel particles. Examples of both types of coats made using the described technique are discussed and illustrated.
Fuel Injection Split Model for Diesel Engine Advanced Combustion Mode Control

Comparing to the air-path loop control, the fuel injection on Diesel engines is a fast control actuator in the realization of advanced combustion modes and the smooth transitions during combustion mode switchings. In this paper, given the estimated in-cylinder conditions (ICCs) at the crank angle of intake valve closing (IVC), models describing the relationship between the fuel injection split ratio and the combustion performance indices, such as CA50 and IMEP, are proposed and validated through experimental data obtained on a medium-duty Diesel engine. Such models can be potentially instrumental in systematic and cooperative control of air-path and fuel-path in the Diesel engine advanced combustion modes and the transient operations during combustion mode switching processes.Copyright © 2012 by ASME
Grafting in acute spinal cord injury: Morphological and immunological aspects of transplanted adult rat enteric ganglia

Abstract We have studied allogeneic transplants of adult rat enteric ganglia in order to evaluate their use as donor tissue for eventual autografts in rodent spinal cord injury models. Female Sprague-Dawley rats of similar weights served either as transplant donors or as recipients. A glass micropipette of 0.8 mm diameter was used to create a local penetrating injury of the lower thoracic spinal cord and the transplant material was pressure injected through the pipette within the neural parenchyma. Ganglia of the myenteric plexus adhering to the stratum longitudinal muscularis were dissected from portions of the jejunum and ileum. Following partial enzymatic digestion and mechanical disruption of the myenteric plexus and muscle tissue (labeled with adherent rhodamine conjugated microbeads), reaggregates of myenteric plexus and muscle were suspended in growth medium and cultured in vitro for one to two days prior to transplantation. Transplants were examined at three, four, six, and eight weeks after surgery. Some of the donor tissue was grown in vitro, in order to determine its cellular composition. These cultured explants were fixed after 10 days, and like myenteric plexus and muscle grafts, were stained histochemically for acetylcholinesterase and observed by fluorescence and light microscopy. At the earlier post-transplantation periods, grafts contained several clusters of enteric ganglion cells that were positive for acetylcholinesterase and exhibited ultrastructural features characteristic of the enteric nervous system. They had well-defined boundaries. Reactive astrocytes and their processes remained located within the host spinal cord adjacent to the boundary region of the grafts. Likewise, macrophages were located in areas abutting the graft. Newly formed vasculature penetrated the graft interior and appeared to be continuous with the host vessels. Grafts grown for at least eight weeks were characterized by interdigitating boundaries. Finger-like protrusions of graft tissue containing fibroblasts and collagen intermixed with adjacent gray and white matter of the host cord. Such transplants also had reactive astrocytes and ED1-positive macrophages. At this later stage, several groups of ganglion cells were identified that were intensely acetylcholinesterase-positive; however, only two of four grafts were recovered, whereas two of the transplants degenerated. We postulate that degeneration of allogeneic grafts may occur as a result of ongoing immune responses of the host which could be prevented by use of autogeneic enteric ganglia. Our studies show that fully differentiated enteric ganglia can survive transplantation to acutely injured spinal cord of adult rats.
Background Spectral Features for Moderate-Power Nitrogen Microwave-Induced Plasma-Mass Spectrometry

The mass spectral background features of a moderate-power nitrogen microwave-induced plasma are presented. In general, the mass spectral background obtained from a nitrogen plasma is less congested at low mass than is the case with argon ICP-MS. In addition, there are no significant (less than 20 counts per second) background species above mass 60. At normal multiplier voltage, the major background species found in a dry nitrogen plasma include 14N+, 14NH+, 14N2+, 14N2H+, 14N16O+, 14N16OH+, 14N3+, and 14N4+. This background is unchanged by the nebulization of deionized water, 5% (v/v) acids (nitric, hydrochloric, and sulfuric acids), and 5% (v/v) methanol solutions. These background species do not interfere with the determination of K, Ca, and Se at their major isotopes, which commonly have interfering background species in Ar ICP-MS. On the basis of the nebulization of 5% HCI and methanol in the nitrogen plasma, As and Cr do not have isobaric interferences at their major isotope masses 75 and 52. In addition, preliminary studies on the effect of Na as a concomitant element on analyte signals indicate severe enhancement or suppression of analyte signals.
Aggression, and the Acquisition and Function of Social Dominance in Female Anolis Carolinensis

Female green anoles, Anolis carolinensis, were paired in terraria to investigate behavioral components of social interaction. Resources (perching sites, prey, and males as potential mates) were limited to assess their importance to cohabiting females. During interaction, paired females exhibited aggressive social behavior which contributed to the development of dominant-subordinate relationships. Dominant status and its relationship to differential resource acquisition was defined primarily by frequency of displacement of another female. Along with displacement, dominant females also had increased frequency of assertion displays, challenge displays, attacks and biting (Figs 1 & 2). Subordinate females were displaced more often and assumed submissive postures. No differences were found between dominant and subordinate females for perch site selection, body color or in prey capturing latency or success (Figs 3 & 4). Perch site elevation was not different between dominant and subordinate females, but was significantly lower than males. The color of paired females was not different unless males were present, in which case dominant females were darker. Paired females also respond differently to courtship display (Fig. 5). Dominant females responded with displays significantly more often than subordinate females to male courtship, indicating receptivity. The role of dominant-subordinate relationships among female A. carolinensis may include courtship and reproductive success as an important component, with consequences for the outcome of aggressive and reproductive social interactions with males.
Resonant scattering from inhomogeneous nonspherical targets

Abstract A method is proposed for solving problems in which either scalar or vector waves impinge at an arbitrary angle on an inhomogeneous nonspherical target whose size is comparable to the wavelength of the incident radiation. This method reduces a partial differential equation, the Helmholtz wave equation, to an ordinary differential equation through selection of angular trial functions composed of weighted sums of spherical harmonics. The wave equation then becomes a coupled set of radial differential equations which are discretized and solved by matrix methods, enforcing boundary conditions on the surface of the smallest sphere which completely encloses the target. The method is an extension of partial wave expansion and reduces to it exactly when the target is spherically symmetric.
Nutritional requirements of Plasmodium falciparum in culture. II. Effects of antimetabolites in a semi-defined medium.

A semi-defined minimal medium, in which pantothenic acid is the only vitamin, was used to culture Plasmodium falciparum for the analysis of antimetabolite drugs. Analogs of riboflavin, nicotinamide, pyridoxine, and thiamin inhibited the growth of this parasite; for each drug, effects were much more pronounced after 96 h of exposure compared to 48 h. The most potent drug examined was 8-methylamino-8-desmethyl riboflavin (ICso value approximately 1.0 x M at 96 h). Avidin, a protein which complexes and thus inactivates biotin, did not affect parasite viability. Other antimalarial drugs, including chloroquine and quinine derivatives and antibiotics, were equipotent in the minimal medium and in RPMI 1640. Four strains of P. fakiparum showed only minor differences in sensitivity to these antimetabolites. The use of prolonged drug exposure times and a vitamin-depleted medium allowed the preliminary characterization of antimalarial antimetabolites in vitro. ECHNIQUES for the continuous cultivation of Plasmo- T dium falciparum (42) have facilitated investigations of par- asite biology. A greater understanding of the biochemistry of this organism is essential for the rational development of new drugs for malaria; containment of drug resistance (6, 24, 46) may require novel therapeutic agents. The recently developed minimal medium for cultivation of P. fakiparum (9) can be used to investigate the role of water- soluble vitamins in parasite development and multiplication. Although vitamins such as biotin, nicotinamide, pyridoxine, riboflavin, and thiamin are not exogenous requirements for con- tinuous growth (9), inhibition of survival by specific antime- tabolites could more clearly define their importance and offer insight into parasite metabolism. In addition, such antimetabo- lites are known to have prominent anticoccidial effects; these parasites are taxonomically closely related to Plasmodium spp., but few of these drugs have been examined in P. falciparum. These drugs represent a class of compounds which may be of importance as prototype antimalarials.
On the zirconium oxide neutral cluster distribution in the gas phase: detection through 118 nm single photon, and 193 and 355 nm multiphoton, ionization.

Zirconium oxide clusters are generated in the gas phase by laser ablation of the metal into a flow of ca. 5% O2/95% He at 100 psig and supersonic expansion into a vacuum chamber. Mass spectra of neutral gas phase zirconium oxide clusters are obtained through photoionization at three different laser wavelengths: 118, 193, and 355 nm. Ionization of the clusters with 118 nm laser radiation is through a single photon ionization mechanism, while ionization by 193 and 355 nm laser radiation is through a multiphoton (three or more photon) mechanism. Fragment ion features are observed in the mass spectra of ZrmOn+ for only the 193 nm and 355 nm ionization schemes. The true neutral ZrmOn cluster distribution is obtained only through 118 nm single photon ionization, as verified by mass spectral peak linewidths and calculations of the cluster binding energies, ionization energies, and fragmentation rates. The neutral cluster distribution consists mainly of the series ZrmO2m and ZrmO2m+1 for m=1,…,∼30.
Psychiatric consultation for Project Head Start.

Psychiatric and/or “mental health” services for the Project Head Start program need to be adapted to the character of the population group to be dealt with. This requires special knowledge and skills, not only in relation to the psychopathology of the preschool-age child, but also to the subtleties of family pathology and the ways in which a disturbed child of this age is simultaneously “causative agent” and “victim.” Because of the socioeconomic characteristics of many of the groups to be served, special adaptation to travel problems and location will need to be made. Also, because of these factors and the limitations of motivation, the standard model of psychotherapy will in most instances not be feasible. Maximum use of the nursery school teachers as therapeutic agents will be necessary. With appropriate and continuing consultation, they should emerge as pivotal educative figures for the whole family.
Ballistic carbon nanotube field-effect transistors

A common feature of the single-walled carbon-nanotube field-effect transistors fabricated to date has been the presence of a Schottky barrier at the nanotube–metal junctions1,2,3. These energy barriers severely limit transistor conductance in the ‘ON’ state, and reduce the current delivery capability—a key determinant of device performance. Here we show that contacting semiconducting single-walled nanotubes by palladium, a noble metal with high work function and good wetting interactions with nanotubes, greatly reduces or eliminates the barriers for transport through the valence band of nanotubes. In situ modification of the electrode work function by hydrogen is carried out to shed light on the nature of the contacts. With Pd contacts, the ‘ON’ states of semiconducting nanotubes can behave like ohmically contacted ballistic metallic tubes, exhibiting room-temperature conductance near the ballistic transport limit of 4e2/h (refs 4–6), high current-carrying capability (∼25 µA per tube), and Fabry–Perot interferences5 at low temperatures. Under high voltage operation, the current saturation appears to be set by backscattering of the charge carriers by optical phonons. High-performance ballistic nanotube field-effect transistors with zero or slightly negative Schottky barriers are thus realized.
Cyanophenyloximes: Reliable and Versatile Tools for Hydrogen-Bond Directed Supramolecular Synthesis of Cocrystals

A systematic structural and spectroscopic examination of the products resulting from cocrystallization reactions between three types of phenyloximes R−CN−OH (where R = H, Me, or CN) and a series of N-heterocyclic hydrogen-bond acceptors demonstrates that the acidity of the oxime -OH hydrogen-bond donor is crucial to the efficacy of the supramolecular assembly process. Cyanophenyloximes are comparable to carboxylic acids, in terms of success rate, whereas the significantly less acidic CH3- and H-substituted analogues are not effective at generating cocrystals despite close similarities in steric and geometric parameters. The importance and validity of using experimental pKa values and calculated electrostatic potential surfaces as a basis for predicting the supramolecular yield of an O−H···N interaction for driving the formation of cocrystals (within a functional group class) is unambiguously established, and six new crystal structures of cocrystals assembled using oxime···heterocycle-based hydrogen bonds ...
Current Research on Organ Donor Management

A shortage of organs is available for transplantation, with 116,000 patients on the Organ Procurement and Transplantation Network/United Network for Organ Sharing wait list. Because the demand for organs outweighs the supply, considerable care must be taken to maximize the number of organs transplanted per donor and optimize the quality of recovered organs. Studies designed to determine optimal donor management therapies are limited, and this research has many challenges. Although evidenced-based guidelines for managing potential organ donors do not exist, research in this area is increasing. This article reviews the existing literature and highlights recent trials that can guide management.
A method for characterization and quantification of platelet graphite nanofiber edge crystal structure

Abstract Platelet graphite nanofibers are materials produced from the decomposition of carbon monoxide and hydrogen over iron powders. The surface consists of terminated graphite edges, differing from traditional graphite materials in which basal plane graphite surfaces dominate. The 3-dimensional morphology and crystal face exposure on the nanofiber surface was determined by selected area electron diffraction studies. From orientation of the 〈 1 0 1 ¯ 0 〉 “zigzag” and 〈 1 1 2 ¯ 0 〉 “armchair” directions, the concentration of { 1 1 2 ¯ 0 } and { 1 0 1 ¯ 0 } face families on the fiber surface, along with the overall geometry and shape of the nanofibers, were determined. To overcome the problem of large aspect ratio in such materials, the fibers were cleaved along the basal plane, which was oriented perpendicular to the fiber axis. Effectively, the materials were transformed into multiple single crystal graphite structures. The cleaved samples, because of the decreased depth of field, were then observed end on using transmission electron microscopy techniques. It was found that the zigzag/armchair face ratio for most observed structures was ∼1.7/1, but some samples deviated from this ratio. Such knowledge is useful in discerning types of graphite surfaces are exposed when nanostructured carbons are used as catalysts and catalyst supports.
Influence of the Ward colon tumor on the host response to endotoxin.

Cachexia and a decreased immune function are negative prognostic factors for cancer patients. While the decreased immunity results in a greater susceptibility to bacterial infection, the response of the host to the resulting infection is not clear. The experiments reported here were designed to evaluate the toxicity of endotoxin to rats with a transplantable Ward colon tumor (WCT) and to evaluate the mechanism of the observed increase in lethal toxicity. The lethal toxicity of endotoxin (lipopolysaccharide, LPS) at 5 mg/kg, i.p. was evaluated in the first of two experiments. Rats received LPS and were observed for morbidity and weight loss for a period of 11 days. A second experiment was done to evaluate the effect of LPS on the plasma nitrate/nitrite concentrations and plasma indicators of host tissue dysfunction. LPS was administered as previously described but blood and tissues were collected 5 h after LPS administration. LPS resulted in the death of 1 of 12 nontumor-bearing (NTB) rats and a transient weight loss in the survivors. This same dose of LPS, however, resulted in death for 10 of 12 WCT rats with tumor burdens less than 4% of body weight. The response of WCT rats 5 h after LPS was then compared with that of age-matched NTB rats. Plasma albumin concentrations were not affected by LPS in NTB rats but were significantly decreased in WCT rats. Peripheral blood gases were not consistently affected by LPS in either group. Peripheral blood white cell counts, except monocytes, were significantly decreased by LPS in both groups. Monocyte counts in peripheral blood were further reduced in WCT rats compared with NTB rats receiving LPS. The presence of the WCT significantly enhanced the LPS-associated increase in spleen weight. Liver weights were lower in LPS rats but there was no effect of the presence of WCT. The LPS-associated increase in plasma nitrate/nitrite concentration was enhanced by the WCT. The plasma arginine and citrulline concentrations were altered in a manner consistent with an increase in nitric oxide synthesis. An increase in plasma ornithine concentration suggests an increase in arginine metabolism by arginase. The plasma concentration of alanine aminotransferase was significantly elevated when WCT rats received LPS, suggesting enhanced hepatic dysfunction. The plasma blood urea nitrogen concentration was elevated by LPS to a greater extent in the WCT rats than in the NTB controls, indicating increased renal dysfunction. These results demonstrate that the Ward colon tumor increases the host lethal response to the endotoxin, a toxic product of bacterial infections. The mechanisms of lethality may include an increased nitric oxide synthesis in WCT rats and enhanced liver and renal toxicity.
Familial abdominal wall defects

We report 2 families, each having multiple sibs with abdominal wall defects. In family 1, normal parents gave birth to identical (monochorionic, diamniotic) twins. This is the first reported case of gastroschisis occurring in monozygotic twins. In family 2, a normal mother gave birth to a son with omphalocele. Two subsequent pregnancies with a different husband resulted in a stillborn girl with partial atresia of the colon and a liveborn girl with gastroschisis. In neither case were there any associated anomalies. In neither of the 2 families was there consanguinity or history of other abdominal wall defects. The familial occurrence of these defects suggests that 1) multifactorial determination should be considered in at least some cases of abdominal wall defects, 2) the bowel atresias that occasionally accompany gastroschisis may also have a genetic (multifactorial) cause, and 3) some cases of gastroschisis and omphalocele may have the same genetic cause.
Total Synthesis of the Ethyl Ester of the Major Urinary Metabolite of Prostaglandin E2

The preparation of the ethyl ester of the major urinary metabolite of prostaglandin E2 3 is described. The key step is the kinetic opening of the TBS-protected bicyclic ketone 7 with thiophenol.
Evidence That Pituitary Adenylate Cyclase Activating Polypeptide Suppresses Follicle-Stimulating Hormone-β Messenger Ribonucleic Acid Levels by Stimulating Follistatin Gene Transcription1

There is accumulating evidence to suggest that pituitary adenylate cyclase-activating polypeptide (PACAP) may be an important modulator ofgonadotrope function. One of the actions of PACAP identified previously is to decrease FSHbeta messenger RNA (mRNA) levels. In the present series of experiments we demonstrate that PACAP-induced suppression of FSHbeta mRNA correlates with a rise in follistatin mRNA levels in primary pituitary cell cultures. Transient transfection of gonadotrope-derived alphaT3-1 cells with a rat follistatin promoter-luciferase reporter plasmid reveals that PACAP stimulates follistatin gene transcription. PACAP stimulation of LUC activity was maximal at concentrations as low at 1 nM. Furthermore, in alphaT3-1 cells PACAP activation of the follistatin promoter appears to be via the cAMP-dependent protein kinase A pathway. Accordingly, we propose that PACAP stimulates follistatin transcription, which neutralizes activin activity and thereby reduces FSHbeta mRNA. Since PACAP and follistatin are colocalized in multiple tissues including the brain, adrenals, and gonads, our findings may reflect a broadly distributed autocrine/paracrine mechanism for modification of activin effects that is under PACAP control.
Addition of dimethylsilylene to substituted 1,3-butadienes; evidence for concerted 1,2-addition followed by nonconcerted rearrangements via diradical intermediates

Abstract The mechanism for addition of dimethylsilylene to substituted 1,3-butadienes has been established as consisting of a concerted 1,2-addition followed by ring-opening of vinylsilacyclopropane intermediates to diradicals that can cyclize or disproportionate. The substrates studied were cis - and trans -piperylene, isoprene, 2,3-dimethylbutadiene, cis,trans - and trans,trans -2,4-hexadiene, and trans --1,3-hexadiene.
Stable Small Animal Ventilation for Dynamic Lung Imaging to Support Computational Fluid Dynamics Models

Pulmonary computational fluid dynamics models require that three-dimensional images be acquired over multiple points in the dynamic breathing cycle without breath holds or changes in ventilatory mechanics. With small animals, these requirements can result in long imaging times (∼90 minutes), over which lung mechanics, such as compliance, may gradually change if not carefully monitored and controlled. These changes, caused by derecruitment of parenchymal tissue, are manifested as an upward drift in peak inspiratory pressure (PIP) or by changes in the pressure waveform and/or lung volume over the course of the experiment. We demonstrate highly repeatable mechanical ventilation in anesthetized rats over a long duration for dynamic lung x-ray computed tomography (CT) imaging. We describe significant updates to a basic commercial ventilator that was acquired for these experiments. Key to achieving consistent results was the implementation of periodic deep breaths, or sighs, of extended duration to maintain lung recruitment. In addition, continuous monitoring of breath-to-breath pressure and volume waveforms and long-term trends in PIP and flow provide diagnostics of changes in breathing mechanics.
Color-forming reactions of copper(II) with some triphenylmethane dyes and quaternary ammonium salts: spectrophotometric study of the copper—eriochrome cyanine r—cetylpyridinium chloride system

Abstract The color-forming reactions of copper(II) with nine triphenylmethane dyes in the presence of cetyltrimethylammonium bromide and cetylpyridinium chloride (CPC) have been studied. Spectral characteristics of the complexes with eriochrome cyanine R (ECR), chromazurol S (CAS), bromopyrogallol red, and pyrogallolsulfonephthalein are presented. The CAS complexes have the highest molar absorptivities, but the Cu—ECR—CPC system is the only one with an insignificant reagent blank. In the presence of excess of ECR and CPC, a blue complex is formed at pH 7.0–7.8 with. ϵ = 7.2 × 10 4 l mol -1 cm -1 at 593 nm, and the ratio of Cu:ECR:CPC is l:4: q , where q ⩾ 2. Fluoride was used as a masking agent, but most cations tested interfered in the determination of copper with ECR and CPC.