cssi/SciSciGPT-SciSciNet huggingface dataset:
Ion competition and micrococcal nuclease digestion studies of spermidine-condensed calf thymus DNA. Evidence for torus organization by circumferential DNA wrapping.

Abstract Spermidine-condensed calf thymus DNA structures have been studied by ion competition using a sedimentation assay and by micrococcal nuclease digestion. Competitor ions Mg2+, Ca2+ and putrescine2+ show specific ion effects; but all three appear to affect the DNA condensation-decondensation equilibrium caused by spermidine3+ in a qualitatively similar manner, suggesting the spermidine3+-DNA interaction is largely electrostatic. Our data show a hysteresis in condensation and decondensation transition directions. We interpret this in terms of a kinetic block in the condensation direction with decondensation representing the equilibrium state of the system. These results agree with results obtained from related systems using different measurement techniques. Micrococcal nuclease digestion of spermidine-condensed calf thymus DNA produces broad but discrete bands in gel electrophoresis experiments. At least two bands determined to be 760 ± 87 bp and 1355 ± 135 bp, possess the size ratio 1:1.8 ± 0.4 consistent with their forming the monomer and dimer fragments of an arithmetic band series. We rationalize this result in terms of a localized micrococcal nuclease cleavage model of circumferentially-wrapped DNA toruses proposed previously by Marx, K.A. and Reynolds, T.C. (Proc. Natl. Acad. Sci. (1982) 79, 6484–6488). The arithmetic series monomer band (760 ± 87 bp), corresponding to wrapping B DNA once circumferentially about the torus, is in agreement with the electron microscopic measurements of hydrated calf thymus DNA torus circumferences presented by Marx, K.A. and Ruben, G.C. (Nucleic Acids Res. (1983) 11, 1839–1853).
Stability analysis and parasitic effects of negative impedance converter circuits

Stability is a major obstacle preventing practical applications of negative impedance converters (NIC) such as electrically small antenna matching. Return ratio method with a mesh or nodal analysis in frequency domain can provide an insight of the overall stability and performance of a NIC. This paper studies the stability of two types of NICs, based on tunneling diode and cross-coupled pair MOSFET. The influence of device capacitances, load impedance, and bias network are discussed.
Limited proteolysis of human histone deacetylase 1

Histone deacetylase (HDAC) proteins are associated with cell proliferation, differentiation, apoptosis, and cancer. Specifically, HDAC1 is linked with cell growth, a hallmark of cancer formation. HDAC1 is a phosphoprotein and phosphorylation at S421 and S423 promotes HDAC1 enzymatic activity and protein association. While single and double point mutants of HDAC1 at S421 and S423 appear functionally similar, the evidence suggests that HDAC1 is phosphorylated simultaneously at both S421 and S423 in vivo. Additional experiments are necessary to probe the role of double phosphorylation of HDAC1 at S421 and S423. To characterize HDAC1 phosphorylation at S421 and S423, limited proteolysis of HDAC1 was performed for the first time. HDAC1 degraded without production of discrete fragments. By performing concentration-dependent proteolysis, HDAC1 double point mutants with disrupted phosphorylation at S421 and S423 displayed different trypsin sensitivities compared to wild type HDAC1. Unexpectedly, HDAC1 single point mutants with disrupted phosphorylation at either S421 or S423 demonstrated protease sensitivity similar to the wild type HDAC1. Concentration-dependent proteolysis experiments provide evidence that phosphorylation of S421 and S423 individually contribute to HDAC1 function. In addition, the limited proteolysis experiments support a model where associated proteins promote HDAC1 enzymatic activity, reinforcing the importance of protein interactions in HDAC1 structure and function. Finally, because HDAC1 does not display distinct regions of protease sensitivity, the proteolysis studies suggest that HDAC1 comprises inter-related structural regions.
The skills of argument

Introduction Scope of the Investigation The investigation to be described focuses on an individual's thinking processes, and as such it relates most directly to the sizable psychological literature on thinking and reasoning. Yet the work also addresses issues that are prominent in a number of other disciplines. From a philosophical perspective, the present work relates to an increasing interest shown by philosophers in the nature and logic of natural language argumentation (Walton, 1989). As already mentioned, philosophers of education such as Scheffler (1965) have noted the importance of reflective thinking about thought, but their ideas have not been connected explicitly to the analysis of argumentation. Here we offer those with philosophical interests an analysis of elementary argumentive reasoning that is grounded in empirical data about the competencies and incompetencies that people exhibit in their argumentive reasoning about everyday topics. From a language perspective, the present work relates to a growing area of research within discourse analysis pertaining to discourse that is argumentive (Grimshaw, 1990). What are the unique features that characterize argumentive in contrast to other kinds of discourse? Although it does not investigate social discourse directly, the research presented here, focused on the cognitive prerequisites of competent argument, offers some insight regarding the language of argument. From sociological and political perspectives, the present work is relevant to a growing understanding of the complex interrelations that exist between individual and sociological processes (Dowd, 1990).
RISK FACTORS AND ANGIOGRAPHICALLY DETERMINED CORONARY OCCLUSION

An association of coronary artery occlusion, as determined by coronary arteriography with age, prevalence of risk factors and alcohol intake was studied in 1635 male and 371 female heart patients. The degree of coronary artery occlusion was positively related to elevated cholesterol, elevated triglycerides, diabetes, age and history of smoking for both male and female patients. Hypertension was related to the degree of occlusion only for female patients. Male and female patients who had a higher alcohol intake tended to have less extensive occlusion. No positive association was found between obesity and the degree of occlusion. When the patients were divided on the basis of age (less than 50 and greater than or equal to 50 years) the findings did not differ. The lack of finding a relation between obesity and occlusion or between hypertension and occlusion for males differs from the general findings of epidemiologic studies on the relation between these risk factors and coronary heart disease. The authors believe that this discrepancy may either be explained by the way they selected patients (i.e., they selected patients who underwent a diagnostic angiographic examination), or that obesity and hypertension are not directly related to coronary occlusion but influence occlusive disease through some secondary mechanism.
Vitamin B-6 deficiency impairs interleukin 2 production and lymphocyte proliferation in elderly adults.

The effect of vitamin B-6 deficiency on immune response was studied in eight healthy elderly adults. The protocol consisted of a 5-d baseline (BL) period; a vitamin B-6-depletion period of less than or equal to 20 d; three stages of vitamin B-6-repletion, each lasting 21 d; and a 4-d final phase. The amounts of vitamin B-6 ingested during the different phases of the study were 3.00, 15.00, 22.50, and 33.75 micrograms.kg body wt-1.d-1, respectively. During the final phase the subjects ingested 50 mg vitamin B-6/d. Fasting blood was collected at the end of each period. Vitamin B-6 depletion significantly decreased percentage and total number of lymphocytes, mitogenic responses of peripheral blood lymphocytes to T- and B-cell mitogens, and interleukin 2 production. These indices returned to BL values after the third vitamin B-6-repletion period, when the total vitamin B-6 intakes were 1.90 +/- 0.18 mg/d for women and 2.88 +/- 0.17 mg/d for men. Vitamin B-6 deficiency impairs in vitro indices of cell-mediated immunity in healthy elderly adults. This impairment is reversible by vitamin B-6 repletion.
BENZYL CARBAMYL ANALOGUE OF LIGNOCAINE: VASODEPRESSOR MECHANISM OF ACTION

SUMMARY 1. The benzyl carbamyl analogue of lignocaine [2-(diethylaminoacet-amido)-3-carbamyl-4-methyl-5-benzylpyrrole] at an intravenous dose of 4 mg/kg caused a blood pressure decrease of 54 mmHg. 2. A greater hypotensive effect was observed in hypertensive compared to nor-motensive animals. Anaesthesia magnified the vasodepressor effect in both groups. 3. The analogue did not possess centrally-mediated effects on blood pressure but exerted its hypotensive effect via a peripheral mechanism. 4. The analogue produced a relaxant effect on intestinal and vascular smooth muscle while exerting minimal effects on muscarinic, sympathetic, or ganglionic nicotinic receptors. 5. The analogue exhibited less cardiac depressant action on left ventricular rate (dp/dt and force of contraction than lignocaine. 6. Lethal effects for the analogue were first observed at 16 mg/kg following intravenous administration and at 500 mg/kg following intraperitoneal administration. 7. In conclusion, the benzyl carbamyl analogue exhibited direct vascular smooth muscle relaxant activity with less cardiac or CNS side effects than lignocaine.
PeerPressure for automatic troubleshooting

Technical support contributes 17% of the total cost of ownershipof today’s desktop PCs [3]. An important element of technical sup-port is troubleshooting misconﬁgured applications. Misconﬁgura-tion troubleshooting is particularly challenging, because conﬁgura-tion information can be shared and altered by multiple applications.Maintaining healthy conﬁgurations of a computer platform with alarge installed base and numerous third-party software packageshas been recognized as a daunting task [1]. The considerable num-ber of possible conﬁgurations and the difﬁculty in specifying the“golden state” [4], the perfect conﬁguration, have made the prob-lem appear to be intractable.In this paper, we address the problem of misconﬁguration trou-bleshooting. There are two essential goals in designing such a trou-bleshooting system:1. Troubleshooting effectiveness: the system should effectivelyidentify a small set of sick conﬁguration candidates with ashort response time;2. Automation: the system should minimize the number of man-ual steps and the number of users involved.To diagnose misconﬁgurations of an application on a sick ma-chine, it is natural to ﬁnd a healthy machine to compare against [7].Then, the conﬁgurations that differ between the healthy and the sickare misconﬁguration suspects. However, it is difﬁcult to identify a
Lyme disease agent borrows a practical coat.

The bacterium that causes Lyme disease is a manipulative creature. This pathogen exploits a component in the saliva of its vector, a tick, to facilitate invasion of vertebrate hosts.
Photoemission study of Fermi surfaces of pseudomorphic Co, Ni, and Co x Ni 1 − x films on Cu(100)

The k-space electronic structure of ${\mathrm{Co}}_{x}{\mathrm{Ni}}_{1\ensuremath{-}x}$ alloy films epitaxially grown on Cu(100) has been investigated with changing stoichiometry in angle-resolved photoemission, and is compared to the electronic structure of fcc films of Co and Ni, and single-crystalline Cu. We have monitored changes in the Fermi surface with changing stoichiometry and changing magnetic behavior. The measurements show that the sp band is a prominent feature of the Fermi surface throughout k space for all of the alloys and the magnetic $3d$ pseudomorphic fcc films. A band-structure calculation of Ni allows us to identify d-hole pockets which increase in size with changing stoichiometry. Minority spin states highlight specific regions of k space associated with key spanning vectors that determine the oscillatory exchange coupling, which underpins the giant magnetoresistance effect in heterostructures.
Durability of a graphite/epoxy woven composite under combined hygrothermal conditions

The objective of this effort was to evaluate and model the effects of moisture, temperature and combined hygrothermal conditions on the strength and life of a graphite/epoxy woven composite material system. The material system specified is a candidate for use in an advanced subsonic aircraft engine, and the imposed environmental conditions were considered to be representative of engine service conditions. Fatigue and residual strength data showed that initial and residual tensile properties and fatigue life of the material were only minimally affected by any of the imposed environmental conditions for the fatigue stress levels considered in this study. Based on this data, it was shown a residual-strength-based life prediction approach could be used to model strength and life with reasonable results. Fatigue damage progression and accumulation were found to be dependent on testing environment, suggesting that more adverse effects of environment on strength and life may be manifested for other types of loading (i.e., off-axis loading).
Congenital Malformations Induced in Rats by Maternal Nutritional Deficiency. V. Effects of a Purified Diet Lacking Riboflavin.

SummaryCongenital malformations were observed in the offspring of female rats fed a purified diet lacking riboflavin. The malformations were anatomically identical with those described previously as the “pattern of Diet I.”
Aggressive treatment of severe idiopathic focal segmental glomerulosclerosis.

When focal segmental glomerulosclerosis (FSGS) has reached the stage of chronic renal insufficiency, further progression is usually considered inevitable. African-American patients are believed to exhibit a particularly aggressive form of FSGS. We have treated five African-American patients, aged 11–18 years, with FSGS and reduced renal function using intensive intravenous methylprednisolone protocol, combined with chlorambucil in three cases. All patients had a pretreatment creatinine clearance of less than 50 ml/min per 1.73 m2. Three patients responded with normalization of creatinine clearance and serum albumin levels and had no or only minimal proteinuria at latest follow-up. One patient showed no improvement and one patient progressed to end-stage renal disease. These findings indicate, for the first time, that even severe FSGS may respond to aggressive methylprednisolone with or without alkylating agent treatment, and that African-American race does not preclude a favorable response.
Separating and measuring the regulation and load-following ancillary services

Abstract Together, regulation and load-following address the temporal variations in load (and generation that does not accurately follow control signals). The key distinction between load-following and regulation is the time period over which these fluctuations occur. Regulation responds to rapid load fluctuations (on the order of one minute) and load following responds to slower changes (on the order of five to thirty minutes). Load-following is defined as the 30-minute rolling average of system load; regulation is then the difference between actual load for each 30-second interval and the rolling average. Hourly load-following is defined as the difference between the highest and lowest values of the rolling average within the hour. Regulation is defined as the standard deviation of the 120 regulation values for the hour. Finally, the implications of the current block-scheduling conventions on load following and regulation are discussed, as is the need for a new scheduling convention.
An automated apparatus for quantitative aliquot measurement of phosphorylated intermediates.

Abstract An automatic dry ashing apparatus is described. It permits the colorimetric measurement of organic phosphate compounds in the nanomole range either as discrete samples or as the effluent from a column. In its present form it can be used to ash fractions up to 0.5 ml at rates up to three per minute.
Four regions of allelic imbalance on 17q12-qter associated with high-grade breast tumors.

Rearrangements or loss of chromosome 17 are frequent events in breast tumors. Chromosome 17 contains at least four genes implicated in breast cancer (TP53, ERBB2 (Her2/neu), BRCA1, and NM23), as well as other putative tumor suppressor genes and oncogenes implicated in loss of heterozygosity or allelic imbalance studies. Allelic imbalance represents the addition or loss of genetic material in tumor samples, providing circumstantial evidence for the location of cancer related genes. We have analyzed a panel of 85 breast tumor/normal tissue pairs with 21 PCR-based short tandem repeat (STR) markers located at 17q12-qter to more precisely define regions of allelic imbalance and to determine their relation to clinical parameters. Our analysis revealed at least four common regions of allelic imbalance: proximal to BRCA1, including D17S800 (17q12); distal to NM23 around D17S787 (17q22); near the growth hormone (GH) locus, at D17S948 (17q23-24); and between markers D17S937 and D17S802 (17q25). These data also reveal that loss (or gain) of 17q genetic material correlates with poorly differentiated (grade III) tumors (P = <0.001), high S phase fraction (P = 0.034), and positive TP53 immunohistochemical staining (P = 0.011). However, steroid receptor status, ERBB2 (Her2/neu) staining, and aneuploidy do not correlate with allelic imbalance at 17q. Genes Chromosomes Cancer 20:354–362, 1997. © 1997 Wiley-Liss, Inc.
Visualization-Based Mapping of Language Function in the Brain

Abstract Cortical language maps, obtained through intraoperative electrical stimulation studies, provide a rich source of information for research on language organization. Previous studies have shown interesting correlations between the distribution of essential language sites and such behavioral indicators as verbal IQ and have provided suggestive evidence for regarding human language cortex as an organization of multiple distributed systems. Noninvasive studies using ECoG, PET, and functional MR lend support to this model; however, there as yet are no studies that integrate these two forms of information. In this paper we describe a method for mapping the stimulation data onto a 3-D MRI-based neuroanatomic model of the individual patient. The mapping is done by comparing an intraoperative photograph of the exposed cortical surface with a computer-based MR visualization of the surface, interactively indicating corresponding stimulation sites, and recording 3-D MR machine coordinates of the indicated sites. Repeatability studies were performed to validate the accuracy of the mapping technique. Six observers—a neurosurgeon, a radiologist, and four computer scientists, independently mapped 218 stimulation sites from 12 patients. The mean distance of a mapping from the mean location of each site was 2.07 mm, with a standard deviation of 1.5 mm, or within 5.07 mm with 95% confidence. Since the surgical sites are accurate within approximately 1 cm, these results show that the visualization-based approach is accurate within the limits of the stimulation maps. When incorporated within the kind of information system envisioned by the Human Brain Project, this anatomically based method will not only provide a key link between noninvasive and invasive approaches to understanding language organization, but will also provide the basis for studying the relationship between language function and anatomical variability.
Gas-phase reactions of MS+ ions (M = Fe, Co, Ni) with alkanes. An FTMS study

Abstract The gas-phase reactions of MS + ions (M = Fe, Co, Ni) with small alkanes are reported. MS + reacts with hydrocarbons primarily by H 2 S loss from the collision complex. This complex can further dissociate by dehydrogenation, creating a metal-polyolefin complex, or by loss of small alkenes. These latter dissociations are similar to the collision-induced dissociation decomposition pathways for the metal-olefin complex and suggest that H 2 S loss leaves an internally excited metal-olefin complex. As has been observed for a variety of mono-ligated metal species, MS + shows a preference for CH bond insertion, leading to dehydrogenation, compared with the bare metal ions which predominantly attack CC bonds. The sulfur ligand does not activate reactions as much as an oxygen ligand, which may be attributed to the fact that H 2 S loss is less exothermic than H 2 O loss. Photodissociation threshold measurements yield D ° (FE + −S) = 65 ± 5 kcal mol −1 , D °(Co + −S) = 62 ± 5 kcal mol −1 , and D °(Ni + −S) = 60 ± 5 kcal mol −1 , from which additional thermochemical information is derived.
Voluntary Intake of Four Hay Types by Horses

Abstract Alfalfa, teff, oat, and wheat hays were fed to eight mature horses to determine voluntary intake of each hay type. After a 2-week adaptation period during which each horse was offered all four hay types each day, a 4-week study was conducted in which two horses were offered each type of hay each week, usually at the rate of 2.2% of initial body weight. Refused feed was collected and weighed the last 5 days of each week to calculate voluntary intake. Horses consumed significantly more alfalfa hay than the other hays. Wheat and teff hays were consumed in significantly lower amounts than alfalfa, but significantly more than oat hay. Across the 5 days during which voluntary intake was measured each week, hay consumption increased each day, reaching levels significantly greater than day 1 by day 4, when measured as a percentage of body weight, and day 5 when measured as a percentage of feed offered. Only alfalfa hay, at the amount consumed, met 100% of nutrient requirements for digestible energy, crude protein, lysine, calcium, and phosphorus for horses in maintenance condition. Teff hay met all nutrient requirements except digestible energy. Neither wheat nor oat hays met 100% of any of these nutrient requirements. Alfalfa and teff hays averaged about 12% nonstructural carbohydrate content (NSC), whereas wheat and oats hays contained about 30% NSC. The lower NSC content of the alfalfa and teff hays makes these more suitable for horses with problems related to carbohydrate metabolism or for refeeding starving horses.
Is there a role for artificial intelligence in sociological theorizing

This article discusses the role artificial intelligence techniques can play in developing sociological theories. First, artificial intelligence is briefly introduced, and key features that distinguish this from other computing approaches are identified. Then several recent attempts to employ artificial intelligence programming strategies to assist in theory construction in sociology are described to illustrate the variety of contributions artificial intelligence can bring to sociological theorizing. Finally, some of the future prospects for artificial intelligence and sociological theorizing are discussed.
Effects of Geocell Confinement on Strength and Deformation Behavior of Gravel

AbstractIn past years, railroad transportation has been of growing interest because of its efficiency and advancement in railway technologies. However, many issues arise because of the variability in subsurface conditions along the sizeable lengths of track that exist. One very important issue is the need for significant upkeep and maintenance for railways passing over areas of poor soil conditions as a result of continuous deformation and a lack of stiffness from the foundation. One general solution for lack of substructure integrity has been confinement, applied through a variety of reinforcement types, including geocell. To investigate the effectiveness of geocell confinement on substructure integrity, a series of embankment model tests with different configurations of geocell placement (one layer and two layers of geocell) were constructed and loaded monotonically and cyclically for comparison with unreinforced, control tests. On the completion of these tests, the model embankments were simulated nume...
Short line electromigration characteristics and their applications for circuit design

Technology scaling has led to severe electromigration degradation for advanced interconnects. Taking full advantage of the Blech effect benefit has become more and more important for circuit design to overcome this EM performance degradation. Due to the wide range of circuit design layout variations, understanding the EM characteristics of the short lines closely related to the real circuit and chip design applications is needed. In this study, EM characteristics of a wide range of different short line structures are investigated. These structures include simple short line segments, short line segments with branches and with passive passing lines on top, and long lines with only a short portion carrying current. Implications of these results to circuit and chip design are also discussed.
Spatial correlations in nonequilibrium systems: The effect of diffusion

Abstract We show how the ideas of the fluctuation-dissipation theory can be used to calculate spatial correlations in interacting systems away from equilibrium. The only spatially dependent dissipative process considered is diffusion, and spatial correlations are generated by the nonlocal spatial dependence of the chemical potential. The results are the lowest order in a hierarchy of generalized hydrodynamic type calculations applicable to nonequilibrium systems. We derive equations for the density correlation functions at stationary state supported by diffusive fluxes and show that they have the local equilibrium form. The static correlation function is obtained from the fluctuation-dissipation theorem, which we show to be equivalent to the Ornstein-Zernike integral equation. At equilibrium we demonstrate that the dynamical structure factor obtained by these methods includes the expected wave-vector dependent diffusion constant. Finally we derive a necessary and sufficient condition for local equilibrium to obtain at a stationary state and show by explicit calculation that chemical processes can give rise to significant nonequilibrium correlations.
Oxidative Fragmentation of 9-Aminomethylacridan

9-Aminomethylacridan (Ia) and N,N-dimethyl-9-aminomethylacridan (IVa) were subjected to sodium 1,2-naphthoquinone-4-sulfonate and nitrous acid. Fragmentation of the aminomethyl side chain during oxidation to produce acridine was observed with Ia but not with IVa. A mechanism based on electrophilic attack at the primary amine nitrogen of the side chain is proposed for the oxidation of Ia and similar compounds. The synthesis and purification of the new compounds, Ia and its acetamide, IVa, 9-hydroxymethylacridan, and the acetamide of 9-aminomethylacridine are described.
Removal of nitric oxide from flue gas with iron thiochelate aqueous solution in a turbulent contact absorber

An iron(II) thiochelate has been developed for use an an additive in a wet flue gas scrubber for simultaneous removal of SO{sub 2} and NO{sub x} from flue gas. The additive enhances the solubility of NO in scrubbing liquor by binding NO to form an iron nitrosyl thiochelate. The effect of oxygen on NO absorption in iron(II) thiochelate aqueous solutions, as well as in iron(II)(EDTA) solutions, has been studied. The results showed that the iron(II) thiochelate is more resistant to oxidation by oxygen than the conventional iron(II)(EDTA) additive. Parametric studies of the absorption efficiency of NO were performed in a bench-scale Turbulent Contact Absorber (TCA). Based on the bench-scale test results, a prediction of the performance of a full-scale spray absorber has been made. 15 refs., 7 figs.
Impact of acids on the structure and composition of Linde Type A zeolites for use in reverse osmosis membranes for recovery of urine-containing wastewaters

Abstract On the International Space Station (ISS) there are low pH, urine containing wastewaters that need to be recycled. We evaluated the effects of synthetic ISS wastewater on Linde Type A (LTA) zeolites to assess their applicability in membrane separations to produce potable water. Specifically, we studied the impact of the four acid-producing components found in the wastewater: chromium(VI) oxide, potassium phosphate monobasic, sodium phosphate monobasic dihydrate and sulfuric acid. We characterized effects of the acids on crystal structure, bonding, surface morphology and solid phase composition of the LTA zeolites. After 24 h of exposure to synthetic wastewater brine (pH 1.94), the zeolites sustained some damage with extensive structural degradation occurring after 128 h. The crystal structure of the LTA particles completely degraded in all acid-type solutions with a pH below 1 and in phosphate solutions with a pH below 5. The structural degradation resulted from the removal of aluminum from the zeolite framework. Additionally, we observed that phosphate caused changes in bonding of the zeolite, through removal of silicon from the framework and formation of aluminum phosphate precipitates. Ultimately, we found that the presence of acidic anions (specifically dihydrogen phosphate anions that catalyzed aluminum and silicon removal), rather than pH, was the most significant factor causing degradation of LTA in dihydrogen phosphate-containing solutions. Our results indicate that Linde Type A zeolites are inappropriate for use with low-pH, dihydrogen phosphate containing solutions.
Androgen Synthesis in Absence of Leydig and Sertoli Cells in a Germ Cell Fraction from Rat Seminiferous Tubules

Seminiferous tubules of rat testes were exposed to distilled water to lyse the interstitial cells. After homogenization in isotonic phosphate saline, intact viable germ cells were recovered. Straining through a layer of Sephadex-G 25 or gtasswoot removed flagellate cells and Sertoti cells. The germ cells were separated by velocity sedimentation in a sucrose gradient at 1 X g into spermatocyte and spermatid enriched fractions. The spermatids were further resolved into round and elongating spermatids by centrifugation in an isopycnic Ficolh gradient. The al)sence of Leydig and Sertoli cells from the germ cell suspensions was confirmed by cytological and histochemical criteria. Incubation of the cell fractions with progesterone showed that the ability of the germ cells to convert progesterone to testosterone resided in the spermatocyte enriched fraction. This fraction also produced testosterone on incubation without added steroid precursor and with slight stimulation by added LII. These findings suggest that germ cells at the primary spermatocyte stage have the capability to produce androgen not only from external progesterone, but also from endogenous steroid precursors. The androgen content of mete testis fluid may be augmented to a limited, but significant, extent by the activity of intratubular cells.
Nanostructure formation mechanism and ion diffusion in iron–titanium composite materials with chemical looping redox reactions

Iron oxide composites are enabling materials in energy conversion systems including chemical looping and photocatalysis. Extensive earlier experimental findings indicate that inert oxides such as titanium oxide can greatly improve the reactivity of iron oxide over multiple redox cycles. Knowledge on the evolution of the nanoscale morphology of the Fe–Ti materials during the oxidation and reduction is thus of considerable importance. It is also of interest to the fundamental understanding of the ion diffusion mechanism in the reaction processes. In this study, Fe–Ti composite microparticles undergoing cycles of oxidation and reduction are examined at the nano-scale, and the interfacial characteristics of the iron titanium oxides within the composites are probed. Nanobelts are observed to simultaneously form on the microparticle surface during the oxidation at 700 °C, while microblades are found at 900 °C. Additionally, unlike pure iron microparticles that become dense on surface due to sintering effect, Fe–Ti microparticles are transformed into porous particles after redox cycles. The atomistic thermodynamics methods and density functional theory calculations are carried out to investigate the ionic diffusion and vacancy formation during the oxidation and reduction process. A number of surface configurations are considered, and the Ti–Ti–O– terminated surface is computed to the most stable surface structure at experimental conditions. It was found that in oxidation processes, surface Ti atoms are more favorable for oxygen adsorption and dissociation than Fe atoms. The energy barrier of Fe ion diffusion towards the surface, on the other hand, is lower than Ti ion diffusion, which contributes to the Fe2O3-dominant nanobelt formation. The volume change due to high temperature associated with the solid state transformation at the Fe2O3/FeTiO3 interface produces compressive stresses, which stimulate Fe2O3 nanobelt growth to accompany the interface reaction. Also, as the vacancy formation energy of FeTiO3 is lower than Fe2O3 in the reduction process, it indicates that it is easier for a FeTiO3 surface to form vacancy defects, thereby enhancing the porous surface structure formation and O2 diffusivity. The good agreements between experiments and DFT calculations further substantiate nanostructure formation mechanism in redox reactions of iron titanium composite materials.
An extended HLA-D region haplotype associated with celiac disease

Celiac disease has one of the strongest associations with HLA (human leukocyte antigen) class II markers of the known HLA-linked diseases. This association is primarily with the class II serologic specificities HLA-DR3 and -DQw2. We previously described a restriction fragment length polymorphism (RFLP) characterized by the presence of a 4.0-kilobase Rsa I fragment derived from an HLA class II beta-chain gene, which distinguishes the class II HLA haplotype of celiac disease patients from those of many serologically matched controls. We now report the isolation of this beta-chain gene from a bacteriophage genomic library constructed from the DNA of a celiac disease patient. Based on restriction mapping and differential hybridization with class II cDNA and oligonucleotide probes, this gene was identified as one encoding an HLA-DP beta chain. This celiac disease-associated HLA-DP beta-chain gene was flanked by HLA-DP alpha-chain genes and, therefore, was probably in its normal chromosomal location. The HLA-DP alpha-chain genes of celiac disease patients also were studied by RFLP analysis; 84% of HLA-DR3, -DQw2 patients had a 16-kb Xba I fragment that was present in only 36% of HLA-DR3, -DQw2 controls. Moreover, 79% of these patients had both alpha- and beta-chain polymorphisms in contrast to 27% of controls. Thus, celiac disease is associated with a subset of HLA-DR3, -DQw2 haplotypes characterized by HLA-DP alpha- and beta-chain gene RFLPs. Within the celiac-disease patient population, the joint segregation of these HLA-DP genes with those encoding the serologic specificities HLA-DR3 and -DQw2 indicates: (i) that the class II HLA haplotype associated with celiac disease is extended throughout the entire HLA-D region, and (ii) that celiac-disease susceptibility genes may reside as far centromeric on this haplotype as the HLA-DP subregion.
Brownian dynamics simulations of star-branched polymers in dilute solutions in extensional flow

Abstract Using Brownian dynamics (BD) simulations of FENE bead-spring models, the dynamics of star-branched polymers in dilute solutions under extensional flow have been investigated. Studies on star polymers in transient extensional flow reveal that the initial transient stress response at low strains is governed by both the number of arms and the shortest arm. On the other hand, the steady-state behavior of star polymers in elongational flow is limited by the maximum effective “contour” length of the molecules. The distribution of arm extension and birefringence of the star-branched molecule are broader and the mean is shifted to lower values, when compared to equivalent linear systems. As a result, the degree of arm extension at steady-state decreases as the number of arms in the star increases. Both an analysis of individual ensembles in Brownian dynamics simulations and a study of a simple force balance indicate that the constraint imposed on the star arms by the central branch point and contributions from “asymmetric” arm arrangements give rise to overall less extended and oriented star-branched molecules with broader arm extension and birefringence distributions. The results obtained from stress-conformation hysteresis simulation indicate that less-stretched arms exhibit more retarded relaxation, as the number of arms increases in star-branched molecules. The effect of excluded volume (EV) interactions, incorporated through the Lennard–Jones potential, on the dynamics of star polymers in extensional flow appears unimportant.
Citrate-phosphate-dextrose solution for preservation of human blood: a further report.

A comparison of clinically significant in vitro characteristics of ACD and CPD blood is presented. In clinical trials conducted at three hospitals, 586 units of blood collected in CPD in plastic bags were utilized for 622 individual treatments as single units or subdivided aliquots of whole blood, and as packed red cells in 332 patients. The expiration period was 28 days, and five bloods were discarded as outdated. There was one reported pyrexial reaction and one proven bacterial contamination. Forty-two per cent of the bloods or components were issued during the first week, 43 per cent during the second and third weeks, and 15 per cent during the fourth week of storage. Of the total bloods or components issued, 9 per cent of the whole bloods, 25 per cent of the subdivided blood aliquots, and 23 per cent of the packed red cells were transfused during the fourth week of storage. No difficulty with clotting was observed during collection, storage, or transfusion.
Reflections on the Chicano Movement

The Chicano movement was a potent force in American society during the tumultuous decades of the Vietnam War, urban riots, the antiwar movement, and Watergate. One of several politically militant groups that began to challenge the hegemony of the ruling class in the 1960s and 1970s, the movement had several major components: Cesar Chavez and the United Farm Workers (UFW) in California, Reies-L6pez Tijerina's Alianza de Pueblos Libres (Alliance of Free Peoples) and the land-grants struggle in New Mexico, Rodolfo "Corky" Gonzales and the Cruzada (Crusade for Justice) in Colorado, and the electoral movement of Jose Angel Gutierrez in South Texas. Out of this movement sprang hundreds of organizations whose purpose was to improve socioeconomic conditions for Mexican-American people. Today the Chicano movement lies dormant while the "Latino" population continues to grow. Were any of its goals accomplished? If it was a search for identity, then why has the term "Hispanic" come into widespread use, replacing Chicano? These questions have recently been addressed by several scholars in attempts at synthesis and analysis of this important era for the Chicano community. In United We Win Ignacio Garcia gives us a richly textured history of the meteoric rise of the Raza Unida party (RUP) in South Texas and its all-too-rapid disappearance from the political landscape. His book is based upon previously published and unpublished material, primary information from party members' personal files, and interviews of participants. It takes the reader from the early days of the Mexican
Clinicopathological correlations of primary haematuria.

Abstract Recurrent haematuria in children and young adults, in the absence of other symptoms of renal disease or urinary-tract lesions, has usually been ascribed to the pathological lesion of focal or mild proliferative glomerulonephritis. To determine whether other types of renal disease may cause renal haemorrhage, 57 patients with recurrent gross and/or microscopic haematuria were reviewed. Four types of pathological lesions were found in this group of patients: I, focal or latent glomerulonephritis (G.N.) (30 patients); II, diffuse proliferative G.N. (18 patients); III, chronic G.N. (7 patients); and IV, active proliferative G.N. with exudation (2 patients). 35 of the 57 patients were under the age of 20 and the distribution of age was similar in each type of lesion. Episodes of gross haematuria were usually caused by intercurrent infection and/or exercise. In more than half the patients follow-up studies after at least 2 years and as long as 20 years were obtained. There was no evidence of reduced renal function even when renal haemorrhage persisted for many years. Proteinuria (0·5 g. per day) correlated with the severity of the lesion and was found in 8 of 48 patients with focal or diffuse G.N. and in 7 of 9 with chronic or active G.N. This study indicates that recurrent haematuria is associated with several types of glomerulonephritis and suggests that prognosis may relate to the primary lesion. Urinary protein excretion is a useful index in identifying patients with chronic and more severe proliferative glomerulonephritis. Establishment of the correct diagnosis, however, requires morphological classification by renal biopsy.
Blends based on copolymers of methyl methacrylate with phenyl maleimide and tribromophenyl maleimide

The synthesis of methyl methacrylate−phenyl maleimide (MMA−PMI) and methyl methacrylate−tribromophenyl maleimide (MMA−TBPMI) copolymers and the phase behavior of their blends are reported. Copolymer compositions that form miscible binary blends with poly(methyl methacrylate) (PMMA) and polycarbonate (PC) and with copolymers of styrene−acrylonitrile (SAN) and styrene−maleic anhydride (SMA) were established. Repeat unit interaction energies were estimated from isothermal phase boundaries using a binary interaction model and the Flory−Huggins theory. All binary interactions with PMI and TBPMI were found to be endothermic. In general, the interactions with TBPMI are more favorable than with PMI, notwithstanding the interaction with AN where the opposite is true. LCST phase separation was measured for selected blends and compared with predictions based on the Sanchez−Lacombe equation of state.
Goals, Risks, and Choices

Prof. Wilde tells us that the effect of a non-motivational change in the safety environment on the expected accident rate is nil. I suppose that the cautious thing to do is to note that this result is a hypothesis wrapped in an interesting, and perhaps plausible model of behavioral dynamics. We should call for additional empirical and theoretical work, but the major purpose of my comment is to suggest directions for X tracting additional insight from existing literature. An interesting revelation from Wilde's own perusal of the literature is that some of the most recent research was performed without explicit guidance from a risk compensation hypothesis. Risk compensation concepts appear to have developed along independent but parallel paths in at least three social disciplines. The work in psychology, sociology, and economics is faithful to the usual modes of thought in each of these areas, yet what is common among these approaches is much more important than their differences. Prof. Wilde makes statements about underlying variables that determine the risk target at an individual level. This is where his work as a psychologist is most closely linked to that of other disciplines; however, his emphasis on the behavioral dynamics at the individual level -- the perception, decision, and controlled skilled used by the individual in adapting to a target level of risk. This behavior dynamic is been aggregated over individuals and time to obtain a model relating risk targets to accident rates.... Language: en
Theoretical limits on the performance of Stirling engines

This paper describes a mathematical model of engines operating with an ideal Stirling cycle and subject to limited heat transfer, internal thermal losses, and mechanical friction losses. The goal of the paper is to describe the fundamental effects of these imperfections on the performance of an otherwise ideal Stirling engine. These are defects suffered by all real Stirling engines, but the intent here is not to predict the actual performance of specific engines. Rather, the aim is to obtain some mathematical insight into the nature of the theoretical dependence of engine performance upon these imperfections. © 1998 John Wiley & Sons, Ltd.
Production of biodiesel from wet activated sludge

BACKGROUND: The production of biodiesel from activated sludge obtained from Tuscaloosa, AL was optimized based on the yield of fatty acid methyl esters (FAMEs) using an in situ transesterification process. An orthogonal central composite response surface design was considered to investigate the main and interaction effects of temperature, methanol to sludge ratio, and catalyst concentration. RESULTS: The biodiesel yield can be satisfactorily described by the quadratic response surface model with R2 of 0.836 and a statistically not significant lack of fit (p = 0.254). Coded regression coefficients, main effect plots and surface plots indicated that maximum biodiesel yield may be obtained at 75 °C, 30 mL g−1 (methanol/sludge) and 10% volume (catalyst concentration). Numerical optimization showed that at this reaction condition, a biodiesel yield of 3.78% (weight) can be obtained. Experimental verification gave a biodiesel yield of 3.93 ± 0.15% (weight) giving a model error of 7.35%. This indicates high reliability of the model. CONCLUSIONS: The economic analysis showed that the in situ transesterification of wet activated sludge (84.5% weight moisture) is less economical than the in situ transesterification of dried sludge (5% weight moisture). However, sensitivity analysis indicated that the process can be made more economical by reduction of water to 50% (weight). At this level of moisture, a biodiesel break-even price of around $7.00 per gallon is attainable, which is still more expensive than petroleum-based diesel (∼$2.95 per gallon). For the biodiesel from activated sludge to be economically competitive, a biodiesel yield of at least 10% (weight) is necessary. Copyright © 2010 Society of Chemical Industry
A discrete approximation to the one-dimensional vlasov-poisson system

Abstract In its simplest form the kinetic equation of plasma is the one-dimensional Vlasov-Poisson system This system describes the motion of a plasma in one space dimension under the electrostatic approximation of zero magnetic field. The function f is the phase space distribution function (for electrons), f0 is the initial distribution and b is the fixed background distribution of opposite charge. In this paper we develop a discrete approximation to (1.1). The system is first discretized in x and v, but not in t and the trajectories of (1.1) are approximated by the trajectories of this discretized problem. Time discretization is then introduced and the space discretized system is approximated by the space-time discretization which then becomes the final approximation to (1.1).
Dilatation and evacuation at 13 to 15 weeks' gestation versus intra-amniotic saline after 15 weeks' gestation☆

Abstract To evaluate the clinical practice of deferring abortion in patients at 13 to 15 weeks' gestation for abortion by intra-amniotic saline at gestations of 16 weeks or over, the complication rates for 338 gravidas aborted by dilatation and curettage (D&C) and/or vacuum aspiration (VA) at 13 to 15 weeks' gestation, and 442 gravidas at 16 to 18 weeks' gestation aborted by the intra-amniotic instillation of saline were compared. In the 13- to 15-week period, VA is associated with significantly higher rates of cervical injury and the need for secondary procedures to complete the abortion when compared to D&C. Although the total complication rates of D&C at 13 to 15 weeks' gestation and intra-amniotic saline after 15 weeks' gestation were similar, the saline method appeared to be associated with higher rates of potentially serious complications—infections, pulmonary complications—and the need for additional procedures to complete the abortion.