cssi/SciSciGPT-SciSciNet huggingface dataset:
Catalytic Reactions of Phase II Enzymes

Phase I activation enzymes catalyze oxidation, reduction, and hydrolysis reactions, which introduce functional groups to lipophilic foreign compounds. Chapter 3 presents the functional groups introduced by N-oxidation, S-oxidation, aromatic and aliphatic hydroxylation, O- and N-dealkylation, hydrolysis, and epoxidation reactions. Chapter 4 describes the functional properties of oxidases, reductases, and hydrolases, as well as the atoms and groups involved in oxidation, reduction, and hydrolysis reactions. This chapter discusses the chemical reactions catalyzed by major phase I enzymes including cytochrome P450, flavin monooxygenase, amine oxidase, nitroreductase, azoreductase, molybdenum hydroxylase, alcohol dehydrogenase, peroxidase, and carboxylesterase.
Influence of oxygen on development of nitrate respiration in Bacillus stearothermophilus.

A denitrifying mutant of Bacillus stearothermophilus NCA 2184, strain 2184-D, was used to explore the development of nitrate respiration in relation to oxygen respiration. Aerobically grown wild-type cultures could acquire the ability to use nitrate as a result of selection of nitrate-respiring mutants by the presence of nitrate and a reduced oxygen tension. Fluctuation analysis has revealed that the frequency of occurrence of the nitrate-respiring mutant is about 7.5 × 10−8 per bacterium per generation. Nitrate reductase and nitrite reductase appeared to be induced sequentially in strain 2184-D by the addition of nitrate. The formation of both of these enzymes was repressed by oxygen so that cells grown aerobically with nitrate possessed a low basal level of nitrate reducatase and exhibited no denitrification. The rate of synthesis of nitrate reductase increased quickly after addition of nitrate and removal of oxygen. It then declined to a lower steady-state level. Cells grown anaerobically with nitrate retained approximately 30 to 40% of the respiratory activity of aerobically grown cells. Aeration of anaerobically grown cells in the presence of amino acids increased the respiratory activity to normal aerobic levels. This aeration promoted rapid degradation of the existing nitrate reductase with or without the added amino acids.
On the Amount of Nondeterminism and the Power of Verifying (Extended Abstract)

The relationship between nondeterminism and other computational resources is studied based on a special interactive-proof system model GC. Let s(n) be a function and C be a complexity class. Define GC(s(n), C) to be the class of languages that are accepted by verifiers in C that can make an extra O(s(n)) amount of nondeterminism. Our main results are (1) A systematic technique is developed to show that for many functions s(n) and for many complexity classes C, the class GC(s(n), C) has natural complete languages; (2) The class ∏ h 0 of languages accepted by log-time alternating Turing machines making h alternations is precisely the class of languages accepted by uniform families of circuits of depth h; (3) The classes GC(s(n), IIh0), h ≥ 1, characterize precisely the fixed-parameter intractability of NP-hard optimization problems. In particular, the (2h)th level W[2h] of W-hierarchy introduced by Downey and Fellows collapses if and only if \(GC(s(n),\prod _{2h}^0 ) \subseteq P\) for some s(n)=ω(log n).
Visualization of Kinase Activity with FRET‐Based Activity Biosensors

Genetically encodable FRET-based kinase activity reporters (KARs) enable real-time monitoring of kinase activity dynamics in living cells with high spatiotemporal resolution. This unit describes a general protocol for utilizing KARs to visualize kinase activity in living mammalian cells with fluorescence microscopy. Curr. Protoc. Mol. Biol. 91:18.15.1-18.15.9. © 2010 by John Wiley & Sons, Inc. Keywords: kinase activity reporter; FRET; live-cell imaging
The role of cAMP response element-binding proteins in mediating stress-induced vulnerability to drug abuse.

Publisher Summary This chapter discusses the relationship between stress and drug addiction and describes the cyclic adenosine monophosphate (cAMP) response element (CRE)–binding family of transcription factors. The chapter also discusses the role of CRE–binding proteins and their target genes in mediating responses to stress and drug addiction. The chapter also reviews the evidence that CRE‐binding transcription factors are integral in mediating responses to both stressor exposure and drugs of abuse. Exposure to stress alters the cAMP pathway and activation of CREB in distinct brain regions. Activation of phosphorylated CREB (p‐CREB) is observed in the brain after exposure to various stressors, including FS, restraint, predator stress, electroconvulsive shock, and hyperosmotic stress. Several CREB target genes, including BDNF, CRF, and dynorphin, are also implicated in responses to stress and drug addiction. Therefore, CREB activation may yield specific neurochemical and behavioral changes through activation of distinct target genes, in specific brain areas and under different stimulus conditions.
Polymer induced flocculation and separation of particulates from extracts of lignocellulosic materials

Abstract Biofuels from lignocellulosic materials like wood are renewable and sustainable alternatives to petroleum and other fossil fuels. Wood can be grown and harvested without adding to the carbon load of the atmosphere and thus can be part of the solution to the problem posed by global climate changes. Recently much interest has developed on the concept of the forest product biorefinery, where wood is hydrolyzed prior to conventional pulping and papermaking processes and the hydrolyzate consisting of hemicellulose sugars are to be used as a feedstock for biofuels or bioplastics. The purification of the hydrolyzate stream and the separation of fermentable sugars from it thus constitutes an important step in biorefinery processes. The separation of particulate material from wood hydrolyzates is considered in this paper. Sugar maple hardwood was extracted with hot water at 160 °C. The extracts contain hemicelluloses (primarily xylooligomers, xylose and xylan), acetic acid and smaller amounts of lignin. The colloidal stability of the extracts plays a critical role in the separation and purification of the wood extracts. Here, we report the size and charge of the particles in the extract measured using standard instruments based on light scattering and microelectrophoresis. Particles were found to be in the size range from ∼220 nm to 270 nm. Zeta potential measurements showed them to be negatively charged. By treating the extracts with a cationic flocculating agent poly-DADMAC, it was possible to preferentially precipitate out the colloidal fraction containing lignin and lignin derived compounds. Upon the addition of poly-DADMAC the turbidity of the suspension reduced from 920 NTU to 4 NTU in a 24 h period and particulates sedimented from the extract. The lignin concentration was reduced in the supernatant, while the sugar content remained unchanged. The addition of an indifferent electrolyte hindered the effectiveness of the polyelectrolyte. The optimum pH for the effectiveness of the polymer was found to be around 4.5. In order to accelerate the sedimentation of the particles, Kaolin was added to attach to the flocs after adding the polyelectrolyte. Kaolin helped accelerate the separation of the particulates by almost an order of magnitude. This work shows that flocculation with a cationic polyelectrolyte followed by separation by sedimentation, centrifugation or microfiltration can be an effective technique to purify biorefinery wood extracts.
Low loss silica on silicon integrated waveguides

Low-loss waveguides integrated on a silicon substrate are essential components in the design and fabrication of photonic circuits. For this application, a wide operational bandwidth - from visible to infrared wavelengths - is critical. Previous research has yielded waveguides made with various materials and geometries. Several of these devices have achieved low, <0.1dB/cm loss in either the visible or the near-IR. However, to obtain effective confinement of light from the visible through the near-IR, it is necessary to develop waveguides which have near-constant loss and minimal non-linear effects across the entire wavelength range. To overcome this challenge, we have developed novel silica on silicon waveguides fabricated using conventional lithographic techniques and CO2 laser reflow. The entire waveguide is elevated above the higher refractive index silicon substrate, creating an isolated, air-clad waveguide. The cylindrical waveguide's loss was determined by coupling light from 658nm, 980nm, and 1550nm lasers into the waveguide using lensed optical fibers. Due to the inherently low material loss of silica and the isolation from the silicon substrate, the device has low optical loss (0.7-0.9dB/cm) and linear behavior across the entire wavelength, polarization, and input power ranges studied. These on-chip waveguides will benefit many applications, including biodetection and integrated photonics.
The impact of accreditation on CS1 and CS2

The purpose of this paper is to present a summary of the results of a recently conducted electronic survey. This empirical investigation used a nationwide electronic mail questionnaire sent to a random sampling of colleges. The intent of the investigation was to study trends in CS1, primarily, and CS2, secondarily. The survey contained questions concerning course content, language, hardware, closed structured laboratories, and curriculum model. Results were tabulated to detect trends and to learn whether accredited programs and non-accredited programs are providing statistically significant different educational experiences.
Second millenniumB.C. arboriculture in Melanesia: Archaeological evidence from the Mussau Islands

The Malayo-Oceanic tropics have long been regarded as a center for plant domestication, but archaeology has as yet contributed little direct evidence of the processes of domestication in prehistory. Recent excavations of Lapita culture sites in the Mussau Islands dating to 1600–500 B.C. have yielded the first significant assemblage of preserved seeds and other floral remains representing 20+ taxa. Nearly all of these are tree crops of widespread importance in Malayo-Oceanic cultivation systems. These materials confirm that the Lapita culture, responsible for the initial human settlement of much of the southwestern Pacific, included developed arboriculture in its economic system.
Why look in the brain for answers to temporomandibular disorder pain

Temporomandibular disorder (TMD) patients often exhibit widespread clinical pain, as well as greater sensitivity to experimental pain than pain-free controls, suggesting a role of central pathophysiol
Membrane disposition of the M5-M6 hairpin of Na+,K(+)-ATPase alpha subunit is ligand dependent

Extensive proteolytic digestion of Na+,K(+)-ATPase (EC 3.6.1.37) by trypsin produces a preparation where most of the extramembrane portions of the alpha subunit have been digested away and the beta subunit remains essentially intact. The fragment Gln-737-Arg-829 of the Na+,K(+)-ATPase alpha subunit, which includes the putative transmembrane hairpin M5-M6, is readily, selectively, and irreversibly released from the posttryptic membrane preparation after incubation at 37 degrees C for several minutes. Once released from the membrane, the fragment aggregates but remains water soluble. Occlusion of K+ or Rb+ specifically prevents release of the Gln-737-Arg-829 fragment into the supernatant. Labeling of the posttryptic membrane preparation with cysteine-directed reagents revealed that Cys-802 (which is thought to be located within the M6 segment) is protected against the modification by Rb+ while this fragment is in the membrane but can be readily modified upon release. Cation occlusion apparently alters the folding and/or disposition of the M5-M6 fragment in the membrane in a way that does not occur when the fragment migrates to the aqueous phase. The ligand-dependent disposition of the M5-M6 hairpin in the membrane along with recent labeling studies suggest a key role for this segment in cation pumping by Na+,K(+)-ATPase.
Integrative recombination function of bacteriophage λ: Evidence for a site-specific recombination enzyme☆

Abstract We have carried out experiments designed to test the hypothesis that prophage integration proceeds by a site-specific recombination event. We have shown that red− mutants defective in the vegetative recombination system can integrate efficiently and that an intA− mutant defective in integration and excision does not show a general alteration in vegetative recombination. These results show that the red and intA genes appear to specify different functions and therefore that integration is not likely to result from general vegetative recombination. We have looked for integrative recombination as a specific recombination event between phage genes spanning the presumptive site of phage-host recognition, using red− mutants to eliminate “normal” vegetative recombination anywhere along the λ DNA molecule. The results of these experiments show that integrative recombination exists, that it is mediated at least in part by the product of the intA gene, and that the probable site of the integrative recombination is to the right of the region of DNA deleted in the integration defective λb2 mutant.
Applications of coding theory to the design of somatic cell hybrid panels

Abstract The somatic cell hybridization technique for gene mapping depends on assembling panels of rodent-human hybrid clones containing random subsets of the human chromosomes. Such panels should be as informative as possible and permit error detection and error correction for assays of the human gene in the various clones. We derive estimates of the number of randomly generated clones required to be reasonably confident of accurately and unambiguously assigning a gene to a particular human chromosome. The collection of clones in such a random panel is contrasted with minimal panels suggested by algebraic coding theory. To approximate minimal panels we suggest the method of simulated annealing for selecting small, informative panels from larger existing collections of clones. These theoretical insights emphasize the need for more collaboration and coordination among gene mapping groups so that optimal clone panels can be assembled, stored, and distributed.
Measurement of total plasma cysteamine using high-performance liquid chromatography with electrochemical detection.

Abstract Cysteamine is currently used to treat children with the inherited disorder nephropathic cystinosis. A method for the quantitative determination of this aminothiol in human plasma is presented. Whole plasma was reduced with sodium borohydride to convert disulfides to thiols. Cysteamine was then separated by high-performance liquid chromatography and detected electrochemically. The recovery of standard cysteamine added to plasma was 96.6 ± 1.9%. In a patient with cystinosis, an oral dose of cysteamine was absorbed rapidly, with plasma cysteamine reaching a maximum of 56 μ m 1 h after the dose. By 1.8 h the plasma cysteamine concentration had decreased to one-half the maximum value.
Matrix correlation analysis in anthropology and genetics

The comparative analysis of the population variation patterns exhibited by different types of information has long been a genuine anthropological/genetic preoccupation. One of the generic problems attracting repeated attention is the connection between genetic and cultural consequences of population isolation; we expect both patterns and amounts of variation to reflect the same history of group fission and fusion, but what do we see in practice? Numerous techniques have been employed in such work, all based on comparison of different matrices of pairwise distanceslaffinities. A basic difficulty with all of these methods is that the N(N – 1) pairwise elements of an (N × N) matrix cannot be mutually independent. Recently, a versatile test of matrix correlation that allows for this fact, originally developed by Mantel but since extensively modified and extended, has gained popularity in anthropology, as well as geography, ecology, sociology, psychometrics, population biology, and systematics. We present here a general framework for many of these efforts, based on the Mantel test, and then illustrate its use with four examples from our own work and that of our colleagues: (a) genetic affinity and migrational separation in the Bainwa, (b) clinal versus cluster variation in the Yanomama, (c) genetic, linguistic, and geographic affinities among the Chibcha-speaking tribes, and (d) migration and genetic affinity in the Gainj and Kalam. The technique is nonparametric and so general that it is useful for many different types of pattern comparison, even when the connections between different types of information are poorly understood. Greater analytic potential is generally realized when there are definite theoretical connections between the patterns being compared. With theoretical care and a bit of imagination, one can combine the advantages of parametric assumptions with the robustness of nonparametric analysis. Novel analyses and anthropological opportunities are emerging continuously. © 1992 Wiley-Liss, Inc.
The Motorola DSP56000 Digital Signal Processor

The DSP56000 brings 10.25-MIPS performance to digital signal processing and retains enough similarities to other Motorola microprocessors to make it easy to learn and program.
Interval to biochemical failure as a biomarker for cause-specific and overall survival after dose-escalated external beam radiation therapy for prostate cancer.

BACKGROUND: After external beam radiation therapy (EBRT) for prostate cancer, a short interval to biochemical failure of <18 months has been proposed as a surrogate for cause-specific survival. Because EBRT dose influences biochemical failure, the authors investigated the interval to biochemical failure in a cohort of patients treated with dose-escalated EBRT. METHODS: From 1998 to 2008, 710 patients were treated with EBRT (≥75 grays) ± androgen deprivation therapy (ADT) at the University of Michigan. Biochemical failure was defined using the Phoenix consensus definition (nadir + 2 ng/mL). A short interval to biochemical failure was defined as <18 months after completing radiotherapy and/or ADT. The associations between biochemical failure, the interval to biochemical failure, and clinical factors with cause-specific survival (CSS) and overall survival (OS) were evaluated. RESULTS: There were 149 biochemical failures (21%), and short interval to biochemical failure accounted for 14% and 40% of biochemical failures in those with intermediate-risk or high-risk disease, respectively. Biochemical failure impacted CSS (P < .0001) but not OS (P = .36). However, a short interval to biochemical failure predicted decreased CSS (P < .0001; hazard ratio [HR], 5.6; 95% confidence interval [CI], 2.4-13.0) and OS (P < .0001; HR, 4.8; 95% CI, 2.3-10.3) when compared with a long interval to biochemical failure. The 8-year OS was 78% without biochemical failure, compared with 87% with a long interval to biochemical failure (P = .1; HR, 0.7; 95% CI, 0.4-1.1) and 38% with a short interval to biochemical failure (P < .0001; HR, 3.7; 95% CI, 2.3-5.9). On multivariate analysis, a short interval to biochemical failure increased the risk of prostate cancer death (P < .0001; HR, 18.1; 95% CI, 8.4-39) and all cause mortality (P = .0027; HR, 1.5; 95% CI, 1.2-2.1), whereas a long interval to biochemical failure did not. CONCLUSIONS: The relation between the interval to biochemical failure, CSS, and OS was independently validated in patients treated with dose-escalated EBRT. Further evaluation of the interval to biochemical failure as a surrogate endpoint is warranted. Cancer 2012. © 2011 American Cancer Society.
Rational addiction and smoking cessation: An empirical study

Abstract The theory of rational addictive behavior has important implications concerning the impact of a smoker’s socioeconomic status on his or her incentive to quit. The research reported on here extends the previously developed theory of addictive behavior to show its implications for both successful and unsuccessful quitting. Further, it develops hypotheses as to how successful and unsuccessful smoking cessation should relate to an individual’s socioeconomic status if the theory is correct. The hypotheses are then tested empirically, using multinomial logit analysis for a sample of more than 24,000 Californians. The results support the theory of rational addictive behavior.
Expression of a Recombinant Baculovirus for Vitronectin in Insect Cells: Purification, Characterization of Post-translational Modifications and Functional Studies of the Recombinant Protein

Vitronectin (VN) is a cell attachment glycoprotein present in plasma and the extracellular matrix that also has multiple regulatory roles in the complement, coagulation, and fibrinolytic systems. VN stabilizes plasminogen activator inhibitor-1 (PAI-1) with potential binding sites reported at both the somatomedin B and heparin binding domains. In order to perform detailed structure-function analyses of VN, we have produced and expressed a recombinant baculovirus containing the cDNA of human VN. Recombinant VN (rVN) was secreted as a single chain 70-kDa protein into the serum-free culture medium of infected Spodoptera frugiperda cells. Maximum rVN levels of 33.9 mg/liter were obtained 48 hours post-infection. Purification of rVN from serum-free medium was achieved with single-step anion-exchange chromatography. Several native post-translational modifications were demonstrated in rVN including the presence of N-linked oligosaccharides, tyrosine sulfation, and serine phosphorylation. Recombinant VN retained cell and PAI-1 binding capacity. Therefore, rVN expressed for the first time in insect cells retains many post-translational modifications and functional activities and will be useful for additional structure-function analyses.
An Instrument for Skin-Friction Measurements in Thin Boundary Layers

A simple instrument for skin-friction measurements in adiabatic turbulent compressible boundary-layers is described. Its small size makes its use possible in very thin boundary layers. A universal calibration relation is given. A method of applying the instrument to obtain hitherto unavailable measurements of skin-friction in flows with finite pressure-gradient is proposed.
A novel animal model to study hot flashes: no effect of gonadotropin-releasing hormone.

OBJECTIVE Menopausal hot flashes compromise the quality of life for most women. The physiological mechanisms underlying hot flashes remain poorly understood, and the absence of an animal model to investigate hot flashes hinders investigations in this field. METHODS We first developed the sheep as a model to study peripheral skin temperature changes using fever-inducing lipopolysaccharide (LPS; 200 microg/kg) administered to ovary-intact ewes. Because a strong correlation between luteinizing hormone pulses and hot flashes has previously been reported, we then determined whether intravenous gonadotropin-releasing hormone (GnRH; 1 mg), a dose sufficient to elevate cerebrospinal fluid-GnRH concentrations, could modulate ear skin temperature in both ovariectomized and low-estrogen-replaced ovariectomized ewes. RESULTS Some ewes responded to LPS in heart rate and abdominal temperature, but there was no significant effect on either parameter or cheek temperature for the group. In contrast, LPS injection caused a significant (P < 0.001) change in skin temperature at the ear. Ear temperature showed no significant change in response to GnRH relative to control injections in both ovariectomized and low estrogen ewes. CONCLUSIONS We developed a model animal system in the ewe that can accurately detect small changes in peripheral skin temperature. This system has the potential to be extremely useful in future studies investigating the pathology of hot flashes and holds several advantages over previous model systems developed for this research. GnRH per se does not seem to be involved in thermoregulatory events.
Potential underestimation of chlorinated hydrocarbon concentrations in fresh water

Abstract Significant concentrations of PCBs and other chlorinated hydrocarbons have been found in dichloromethane extracts of filtered Niagara River, Canada, water at pH 12 after the water had been thoroughly extracted at pH 1. In samples from 43 dates in 1985-86, the contribution of the basic extract to the total concentration derived from acidic, basic and suspended solids extracts ranged from 0% for 31 of these chemicals to 100% for PCBs 15, 114 and 201, aldrin and p,p′-DDT. When the sums of concentrations of each chemical found in Niagara River water in the acidic, basic and suspended solids extracts over the 43 sampling dates were themselves summed, the basic fraction contributed 40% to the total concentrations of all chemicals, and 48% if only PCBs were considered. Experiments with water from another source showed that some PCBs were recovered in dichloromethane extracts of basic filtered water which had previously been thoroughly extracted under either acidic or neutral conditions. These results indicate that concentrations of chlorinated hydrocarbons in Niagara River water determined by extraction solely at neutral pH, the usual technique, may be underestimated. This finding, which may have general applicability to fresh waters, may be the result of a strong association between a fraction of the dissolved lipophilic chemicals and dissolved organic matter in fresh water, an association that is resistant to organic solvent extraction at acidic or neutral pH, but which is at least partially disrupted by extraction at high pH.
Functional development of grafted vasopressin neurons

Vasopressin neurons, transplanted from normal rat fetuses into the third ventricle of adult Brattleboro rats, alleviate the polydipsia and polyuria of the hosts. Determination of the antidiuretic activity of grafted neurons in hosts with congenital diabetes insipidus provides a convenient model for analyzing the development, plasticity, and function of transplanted central nervous system neurons in mammals.
Methanol and 2-methyl-1-propanol (isobutanol) coupling to ethers and dehydration over Nafion H: Selectivity, kinetics, and mechanism

The dehydration of a mixture of methanol and isobutanol has been studied over the sulfonic acid Nafion H catalyst. Dehydration products consisted of dimethyl ether (DME), di-isobutyl ether (DIBE), methyl-isobutyl ether (MIBE), butenes, octenes, and traces of methyl-tertiarybutyl ether (MTBE). At low temperatures and high alcohol pressures (P ≥ 150 kPa), the dehydration product state was dominated by ether formation with selectivity within the ethers significantly in favor of the mixed ether, MIBE. The rates of ether and butene formation as a function of alcohol pressure could be described by Langmuir-Hinshelwood kinetics in which competitive adsorption of the two alcohols on the surface -SO3H sites was the dominant feature. The kinetics of isobutanol dehydration to isobutene were consistent with a dual-site mechanism involving the cooperative action of a free surface -SO3H site and an adjacent adsorbed alcohol molecule. Dehydration to ethers was consistent with the reaction of two adsorbed alcohols, also by a dual-site mechanism. As a consequence, dehydration to symmetric ethers showed saturation-type kinetics as a function of alcohol pressure, while the rate of isobutene formation went through a distinct maximum. Due to the competitive adsorption of methanol and isobutanol, the mixed ether MIBE was formed at a maximum rate with an optimum ratio of partial pressures of the two alcohols. The high selectivity to MIBE was explained by stronger adsorption of isobutanol on the catalyst surface as compared to methanol. The absence of MTBE and the predominance of products such as MIBE and 2,5-dimethylhexene suggests that dehydration to give "free" carbenium ions that subsequently rearrange to the more stable tertiary intermediate was not occurring. It was proposed that the alcohols react with the -SO3H groups to give oxonium ions or esters. These intermediates couple to give the product ethers or octenes.
Blue-light control of sporangiophore initiation in Phycomyces.

Many fungi produce spores or spore-bearing structures under the control of blue light. Sporangiophores of Phycomyces blakesleeanus are produced continuously along racing tube cultures grown in constant darkness or constant light. However, if a dark-grown culture is exposed to light for a short time on one day a narrow, dense band of sporangiophores is observed the next day at that point of the tube occupied by the mycelial tips during the light pulse. A periodic program with "short days" (e.g., 4 h light; 20 h dark), leads to periodic bands of sporangiophores spaced at intervals corresponding to one period-length (in this case 24 h) of mycelial growth. Sporangiophore initiation is inhibited by a light to dark transition and is stimulated by a dark to light transition. A partial action spectrum of the initiation response, covering the critical 480-540 nm region, strongly suggests that the same photoreceptor pigment is involved as in the phototropic response and light growth response of sporangiophores. Mutants with altered light control of sporangiophore initiation have been found among those selected for altered phototropism. This joint elimination of these two responses to blue light by a single mutation is evidence for a common early transduction system.
Regulation of global genome nucleotide excision repair by SIRT1 through xeroderma pigmentosum C

Disruption of the nucleotide excision repair (NER) pathway by mutations can cause xeroderma pigmentosum, a syndrome predisposing affected individuals to development of skin cancer. The xeroderma pigmentosum C (XPC) protein is essential for initiating global genome NER by recognizing the DNA lesion and recruiting downstream factors. Here we show that inhibition of the deacetylase and longevity factor SIRT1 impairs global genome NER through suppressing the transcription of XPC in a SIRT1 deacetylase-dependent manner. SIRT1 enhances XPC expression by reducing AKT-dependent nuclear localization of the transcription repressor of XPC. Finally, we show that SIRT1 levels are significantly reduced in human skin tumors from Caucasian patients, a population at highest risk. These findings suggest that SIRT1 acts as a tumor suppressor through its role in DNA repair.
Ferromagnetic Order at (100) p(1×1) Surfaces of Bulk Paramagnetic Vanadium

Electron-capture spectroscopy has been used to investigate magnetic order at the topmost atomic layer of atomically clean and flat (100) surfaces of bulk paramagnetic vanadium. From low-energy electron-diffraction measurements, we find a $p(1\ifmmode\times\else\texttimes\fi{}1)$ surface structure. At 300 K, the long-ranged electron-spin polarization amounts to \ensuremath{\sim}34%, clearly demonstrating the existence of ferromagnetic order at the V(100) $p(1\ifmmode\times\else\texttimes\fi{}1)$ surface. With increasing temperature, the electron-spin polarization decreases almost linearly and disappears at a surface Curie temperature ${T}_{\mathrm{C}s}\ensuremath{\approx}540$ K.
Converting standard bivariate polynomials to Bernstein form over arbitrary triangular regions

Abstract An efficient, robust algorithm is presented for converting a bivariate polynomial expressed in the power basis directly to its equivalent Bernstein (Bezier) form over an arbitrary triangular region. It represents an improvement over existing algorithms which, in the course of transforming the polynomial, may encounter degeneracy problems that must be handled with additional logic.
Play behavior and stress responsivity in periadolescent offspring exposed prenatally to cocaine

Play behavior and stress responsiveness were examined in offspring exposed gestationally to cocaine. The subjects were offspring of Sprague-Dawley rat dams given s.c. injections of 40 mg/kg/3 cc cocaine HC1 daily from gestational days 8-20 (C40), pair-fed dams injected daily with saline (PF), and untreated control dams (LC). Periadolescent (postnatal day (P) 30-36) male and female rats were assigned to either pretest Stress or No Stress conditions. Every other day Stress animals were exposed to a stressor (on P30--foot shock; P32--white noise; P34--forced swim; P36--foot shock), with each stressor being administered 4 h prior to a play session. Immobility during one of the stressors, foot shock, was used to assess stress responsiveness. Play sessions consisted of pairing each experimental animal with a same-sex, nonexperimentally manipulated conspecific for 7 min. The results indicated that periadolescent offspring exposed gestationally to cocaine differed from controls in their stress responsivity, as evidenced by a failure to show increased immobility during the final foot shock session. Also, while cocaine-exposed juveniles did not differ from controls in their own play behavior, these offspring elicited less play solicitation from conspecifics, as evidenced by an increased latency to be pounced, and decreased frequency and duration of being pounced. These findings parallel earlier evidence for altered stress responsiveness in adult cocaine-exposed rats and also suggest that prenatal exposure to cocaine results in altered social cues.
Food-web structure of seep sediment macrobenthos from the Gulf of Mexico

Abstract The slope environment of the Gulf of Mexico (GOM) supports dense communities of seep megafaunal invertebrates that rely on endosymbiotic bacteria for nutrition. Seep sediments also contain smaller macrofaunal invertebrates whose nutritional pathways are not well understood. Using stable-isotope analysis, we investigate the utilization of chemosynthetically fixed and methane-derived organic matter by macrofauna. Biological sampling was conducted in three lower-slope GOM seep environs: Green Canyon (GC852, 1428 m), Atwater Valley (AT340, 2230 m), and Alaminos Canyon (AC601, 2384 m). Infaunal δ 13 C and δ 15 N exhibited a broad range of values; most infauna appeared to be heterotrophic, although several taxa had very light δ 15 N and δ 13 C values, indicating possible reliance on chemoautotrophic symbioses. The lightest δ 13 C and δ 15 N values were observed in nematodes (δ 13 C=−54.6±0.1‰, δ 15 N=−6.1±0.2‰) and one gastropod (δ 13 C=−54.1‰, δ 15 N=−1.1‰) from Green Canyon. Mixing-model results indicated that sulfur-oxidizing Beggiatoa may be an important food source for seep infauna; the rate of utilization ranged from 60% to 100% at Green Canyon and Atwater Valley. The overall range in isotope values was similar across the three sites, suggesting that biogeochemical processes may be very similar in these geographically distinct areas.
Electronic structure of molecules using one‐component wave functions and relativistic effective core potentials

A one-component approach to molecular electronic structure is discussed that includes the dominant relativistic effects on valence electrons and yet allows the use of the traditional quantum-chemistry techniques. The approach starts with one-component Cowan–Griffin relativistic orbitals that successfully incorporate the effects of the mass-velocity and Darwin terms present in more complicated wave functions such as the Dirac–Hartree–Fock. The approach then constructs “relativistic” effective core potentials (RECPS) from these orbitals, and uses these to bring the relativistic effects into the molecular electronic calculations. The use of effective one-electron spin-orbit operators in conjunction with these one-component wave functions to include the effects of spin-orbit coupling is discussed. Applications to molecular systems involving heavy atoms and comparisons with available spectroscopic data on molecular geometries and excitation energies are presented. Finally, a new approach to the construction of RECPS encompassing the Hamiltonian and shapeconsistent approach is presented together with a novel analysis of the long-range behavior of the RECPS.
Experimental analysis of embryogenesis of cerebellum in rat. II. Morphogenetic malformations following X-ray irradiation on day 18 of gestation

Rat embryos of 18 days gestation were exposed in utero to 170 R of x-ray irradiation. Embryos were collected six hours, 1, 2, and 3 days after irradiation, and animals of 2-, 6-, 15- and 30-day-old postnatal age were sacrificed. Six hours after irradiation pyknosis of cells was noticed in the external granular layer along the posterior aspect of the cerebellum. Neuroblasts, destined to differentiate into Purkinje cells, were found arrested in their migratory path. During subsequent periods of embryogenesis the external granular layer was found recovered, and clustering of the neuroblasts were disorganized and fragmented. This abnormal clustering of neuroblasts was permanent, and the external granular layer followed the same abnormal pattern in its growth. During postnatal development the internal granular layer also was found to follow the abnormal pattern of Purkinje cell layer. Those abnormal developmental events were seen to lead to malformed folia in the anterior regions of the cerebellum. In addition to it the cerebellum of x-ray irradiated animals appeared smaller than the normal. Issues having a bearing on the differential radiosensitivity of different cells, factors determining the small size of the cerebellum, and cellular events determining the morphogenetic malformations are discussed.
Assessing the Performance of a Sloped-Block Ice-Control Structure

Hardwick, Vt., having experienced 10 ice-jam floods in 30 years , has not experienced one since construction of a sloped-block ice-control structure (ICS) in 1994. This innovative structure consists of four sloped granite blocks spaced across the Lamoille River upstream of the village and adjacent to a treed floodplain. It arrests ice runs, forms partially grounded jams, and retains these jams for hours to days. The measured ice-hydraulic characteristics of the breakup runs and resulting ice jams (e.g., wave celerities and amplitudes, porous-flow seepage coefficients) are similar to characteristics obtained from the 1:10-scale model tests used to develop the structure. Seepage coefficients, and hence jam porosities, generally increase with increasing discharge, and only two breakup events have caused floodplain flow. Water temperatures of 0.1–0.3°C measured during a breakup event confirm that ice melting can account for the rate of porosity increase. Field and model data indicate that ice-jam holding time...
Epitaxial Ferroelectric BaTiO3 Thin Films for Microphotonic Applications

Epitaxial ferroelectric BaTiO3 thin films have been developed as a material for microphotonics. Efforts have been directed toward developing these materials for thin film electro-optic modulators. Films were deposited by metalorganic chemical vapor deposition (MOCVD) on both MgO and silicon substrates. The electro-optic properties of the thin films were measured. For BaTiO3 thin films grown on (100) MgO substrates, the effective electro-optic coefficient, reff depended on the magnitude and direction of the electric field. Coefficients as high as 260 pm/V have been measured. Investigation of BaTiO3 films on silicon has been undertaken. Epitaxial BaTiO3 thin films were deposited by MOCVD on (100) MgO layers grown on silicon (100) substrates by metal-organic molecular beam epitaxy (MOMBE). The MgO serves as the low index optical cladding layer as well as an insulating layer. X-ray diffraction and transmission electron microscopy (TEM) indicated that BaTiO3 was epitaxial with an orientational relation given by BaTiO3 (100)//Si (100) and BaTiO3[011]//Si [011]. Polarization measurements indicated that the BaTiO3 epitaxial films on Si were in the ferroelectric state.
The incidence of positive amniotic fluid cultures in patients in preterm labor with intact membranes

The possible relationship between intrauterine infection and preterm labor has received considerable attention in recent years. The purpose of this study was twofold: first, to determine the frequency of asymptomatic infection in patients who came to the hospital in preterm labor, and second, to determine the significance of a positive amniotic fluid culture in relation to latency period and likelihood of preterm delivery. Patients who came to the hospital in preterm labor with intact membranes between 20 and 35 weeks' gestation underwent transabdominal amniocentesis. Amniotic fluid was sent for Gram stain and culture. Patients received tocolytic therapy as clinically indicated. Of 127 patients cultured, seven (5.5%) had positive amniotic fluid cultures. These patients had a significantly decreased latency period from amniocentesis to delivery (4.4 days versus 28.6 days), and a significantly increased chance of being delivered of preterm infants (100% versus 52.5%), as compared with patients with negative cultures. The rate of positive Gram stain was 7 of 125 positive. However, there was no correlation between positive Gram stain and positive culture results. Similarly, positive Gram stain results were not associated with any difference in the latency period or rate of preterm delivery.
Personal computer storage subsystem workload: measurement and characterization

Abstract This paper discusses the design and implementation of an operating system independent tracing tool for storage subsystem workload in personal computers. This tool measures the workload at the storage subsystem level, and due to hardware assistance it has very little overhead. The workload traces are collected in real-time on a data collection station executing a special data collection program. We use the tool to collect workload traces in real-life Netware-based personal computer environments. We then develop a scheme to analyze and characterize the traced workload.
REDUCING PU(IV) TO PU(III) WITH HYDROXYLAMINE IN NITRIC ACID SOLUTIONS

Los Alamos National Laboratory (LANL) has evaluated different techniques to concentrate and remove plutonium from solutions stored at the Rocky Flats Environmental Technology Site (RFETS). Pu(III) oxalate precipitation was chosen to treat nitric acid solutions because it is a simple and efficient technique for removing plutonium. Reducing Pu(IV) to Pu(III) is a key process step which affects the rest of the processing sequence. Because of differences in the literature1 over the kinetics of the reaction, additional data was obtained and compared with existing data to examine the kinetic relationship, and determine an appropriate relationship for future engineering evaluations. The results and conclusions of this work, along with new experimental data, are presented.
Measurement of bile acid synthesis by 14CO2: The metabolism of propionyl CoA

The relationship between 14CO2 evolution from the catabolism of [26 or 2714C] cholesterol to bile acids was studied in rats with biliary fistulae. When equal quantities of [26 or 2714C] cholesterol and [414C] cholesterol were administered, there was a significant linear relationship between 14CO2 expiration in the breath and [414C] bile acid excreted in the bile. Bile acid synthesis calculated as the ratio of 14CO2: molar specific activity of biliary cholesterol correlated highly with biliary bile acid excretion in the bile acid depleted rat. Phenobarbital, a known inducer of gamma-amino levulenic acid formation from succinyl CoA did not alter the relationship between the 14CO2 estimation of bile acid synthesis and biliary bile acid excretion, indicating that the relationship between [26 or 2714C] cholesterol side chain cleavage and 14CO2 formation was not altered. Phenobarbital, however, did cause a reduction in bile acid synthesis measured by 14CO2 evolution and by biliary bile acid excretion. The 14CO2 method underestimated bile acid excretion. 8.7% in untreated and phenobarbital treated rats respectively. Since 11% of the radioactivity which was expired as 14CO2 was isolated as bile acids, radioactivity cleaved as [1 or 314C] propionyl CoA may enter cholesterol-bile acid biosynthesis resulting in the underestimation of bile acid synthesis. To test whether radioactivity from propionyl CoA enters steroid biosynthesis [114C] propionate and [214C] propionate were given to untreated biliary fistula rats and the biliary lipids excreted in 60 hours were analyzed. Incorporation of radioactivity into cholesterol and bile acids was greater after the administration of [214C] propionate than after [114C] propionate than after [114C] propionate, suggesting that radioactivity from propionyl CoA may enter steroid biosynthesis by metabolic events in which the methylene and carboxyl carbon atoms are differentiated. Although the use of 14CO2 expiration from [26 or 2714C] cholesterol catabolism underestimates the rate of bile acid synthesis, it should have many applications because of the constant relationship between 14CO2 formation and cholesterol side chain cleavage.
Modeling of the microbunching instability

We show that, through careful control of noise sources, it is possible to determine the microbunching gain curve for the FERMI@ELETTRA linac using the particle tracking code elegant. In addition to using a sufficiently large number of particles ($60\ifmmode\times\else\texttimes\fi{}{10}^{6}$), use of a low-pass filter is very helpful in controlling noise and providing convenient intrabin interpolation. Gains of up to 1500 are seen for modulation wavelengths down to $25\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$. Because of the high gain, very small initial modulations are needed to avoid saturation, which further motivates the use of a large number of particles. We also show, for the first time, how the density modulation evolves in detail inside the dipoles of a multichicane system.
A block by block method for the numerical solution of Volterra integral equations

TheO(h6) block-by-block method developed here gives accurate results without the requirement of a start-up procedure and with good computational efficiency. The computing cost, based upon the number of timesk is evaluated, is proportional ton2/2+3n wheren is the number of mesh points. The examples are linear, but were solved by iterating the system of equations (4) fifteen times.
Lupus T cells switched on by DNA hypomethylation via microRNA

The article by Zhao S et al (1) in this issue of Arthritis and Rheumatism gives further insight into the influence of certain microRNAs (miRNAs) on the promoter methylation status regulated by DNA methyltransferases (DNMTs). In recent years, there has been an increased interest in the role of epigenetic modifications of DNA and pathogenetic mechanisms of human diseases such as Systemic Lupus Erythematosus (SLE) (2). Epigenetics is linked to stable and potentially heritable changes in gene expression that do not entail a change in the DNA sequence. DNA methylation and histone modifications are the two major changes that contribute to the epigenome of a cell. The first mechanism usually occurs in the context of CpG dinucleotides at the 5' position of cytosine in the promoter region, leading to functional consequences such as transcriptional repression. In fact, some tissue-specific genes are silenced by promoter methylation (2). Post-translational modifications that occur in histones make up a second group of epigenetic modifications. Both DNA methylation and histone modifications are coupled through different machineries, including DNMTs as well as histone modifying enzymes in multiprotein complexes (2). Three main types of DNMTs are involved in genomic DNA methylation: DNMT1, DNMT3A and DNMT3B. Whereas DNMT1 preferentially replicates existing methylation patterns and maintains DNA methylation, DNMT3A and DNMT3B are responsible for establishing new DNA methylation markers therefore referred to de novo DNA methyltransferase (3).
Six bits for nine colored quarks

The hypercomplex number system of the Dirac equation is used to generalizeSU(2) to the covering group ofSO(4). The basic representations in this number language suggest a parton model of 6 “bits” and 6 “antibits”; one with spin 0, two with spin 1/2, and three with spin 1. The relationship of this to the special relativity group is also considered.