cssi/SciSciGPT-SciSciNet huggingface dataset:
Decreased Spermatogenesis, Fertility, and Altered Slc2A Expression in Akt1−/− and Akt2−/− Testes and Sperm:

Akt is serine/threonine protein kinase associated with various cellular processes and 3 different isoforms exist. This work describes the reproductive phenotype of Akt1−/− and Akt2−/− in male mice. The seminiferous tubule diameter in Akt1−/− testes was less than wild-type or Akt2−/− testes. The expression of phospho-phosphatase and tensin homologue deleted on chromosome 10 (p-PTEN) and phospho-glycogen synthase kinase 3β (GSK-3β) was elevated in Akt1−/− testes. Alterations in expression and localization to the plasma membrane of several facilitative glucose transporters (Slc2a8, 9a and 9b) were detected in these knockout compared to wild-type mice. Apoptotic sperm were more prevalent in both null mice compared to wild-type mice, whereas sperm concentration and motility were significantly lower in the null sperm. Finally, Akt2−/− sperm had a markedly decreased fertilization rate by in vitro fertilization (IVF) and resulting embryos displayed increased fragmentation and poor growth. These results suggest that altered SLC2A expression and increased PTEN and GSK3β activity may be responsible for the decreased spermatogenesis, sperm maturation, and fertilization in the Akt1−/− and Akt2−/− male mice.
Rapid prototyping of micropower sources by laser direct-write

A laser forward-transfer and micromachining process has been developed to fabricate and optimize mesoscale electrochemical power sources, such as primary Zn–Ag2O and secondary Li-ion microbatteries. The laser direct-write technique allows for adding, removing and processing the various material systems required for the fabrication of micropower sources on many types of substrates under ambient conditions. In this work, we demonstrate planar zinc–silver oxide alkaline cell configurations with 1.5–1.55 V open-circuit potentials. The 10 mm2 samples show a flat discharge behavior under constant-current loads and capacities of ∼100 μA h cm-2. Stacked Li-ion cells with 3.80-V open-circuit potentials have also been fabricated and continue to operate after 50 charge/discharge cycles. The 9 mm2 samples exhibit capacities of 110 μA h cm-2.
Mouse Plasminogen Has Oxidized Phosphatidylcholine Adducts That Are Not Metabolized by Lipoprotein-Associated Phospholipase A2 under Basal Conditions

We previously showed that plasminogen (Plg) isolated from the plasma of normal human subjects contains 1–2 moles of oxidized phosphatidylcholine (oxPtdPC) adducts/mole of protein. Moreover, we suggested that these species are generated at the hepatic site and speculated that they may play a role in the reported cardiovascular pathogenicity of Plg. We aimed to determine whether mouse Plg also harbors linked oxPtdPCs and whether these molecules are metabolized by lipoprotein-associated phospholipase A2/PAF acetylhydrolase (Lp-PLA2/PAF-AH), an enzyme specific for hydrolysis of oxPtdPCs. We determined the total concentration of Plg in plasma samples from control (WT) and Lp-PLA2-deficient (KO) mice, we isolated Plg, and assessed its content of oxPtdPCs by immunoblot analyses. We also evaluated whether human recombinant Lp-PLA2 metabolized Plg-linked oxPtdPCs in vivo and in vitro. WT and KO mice expressed comparable levels (14.4–15.8 mg/dL) of plasma Plg, as determined by ELISA. We observed no differences in the content of oxPtdPC in Plg isolated from the two mouse strains and in parallel no changes in oxPtdPC content in mouse Plg following incubation with pure recombinant Lp-PLA2. Plg from mouse plasma contains oxPtdPC adducts that are not affected by the action of Lp-PLA2, suggesting that linkage to Plg protects oxPtdPCs from metabolism during their transport in the plasma. This modification may have important physio-pathological implications related to the function of Plg, oxPtdPCs, or both.
Types and Treatment of Pediatric Sleep Disturbances.

This article provides an overview of pediatric sleep disturbances with emphases on types and treatments. Relationships between sleep disorders and comorbid conditions function to exacerbate and maintain both disorders. An estimated 20% of teenagers experience chronic partial sleep deprivation, resulting in problems with memory, attention, and behavior control. Treatment of choice for chronic partial sleep deprivation involves a comprehensive approach to regularizing the adolescent's sleep–wake schedule. The American Academy of Pediatrics (AAP) calls into question the validity of upward trends in prescribing for children and adolescents who report sleep problems. The AAP has issued a consensus statement on prescribing hypnotics to children and adolescents, arguing that further clinical trials are necessary to determine appropriate pediatric dosages. The AAP recommends that pediatricians educate families about good sleep practices and behavioral interventions. © 2009 Wiley Periodicals, Inc.
Characterization of subunit structural alterations which occur during purification of nitrate reductase from Escherichia coli.

Abstract Nitrate reductase from Escherichia coli , purified to homogeneity after release from membranes by deoxycholate treatment, was composed of two subunits of 155,000 (α) and 58,000 (β) daltons and contained no cytochrome b 1 . Analysis of fractions at different stages of purification by gel electrophoresis and immunoprecipitation revealed that during the early steps of the purification cytochrome b 1 dissociated from the enzyme and the β subunit was altered in size as determined by sodium dodecyl sulfate-gel electrophoresis. Analysis of the peptide patterns obtained by partial proteolysis of isolated α and β subunits established that these subunits are composed of distinct sequences and ruled out a precursor-product relationship between the two subunits. The β subunit was altered during the purification by loss of a 2000-dalton fragment, apparently from its carboxyl terminus. The protease inhibitor tosyllysine chloromethylketone protected nitrate reductase from more extensive degradation by endogenous proteases during the purification but did not prevent the removal of the 2000-dalton fragment. This carboxyl terminal fragment was part of a 15,000-dalton sequence which was removed by trypsin and which was required for the self-associating character of the unmodified enzyme monomers. From the structural changes which occurred during the purification procedure, it is proposed that the carboxyl terminal segment of the β subunit is involved in the binding of nitrate reductase to cytochrome b 1 and its association with the membrane.
Asymmetries in Inclusive Proton-Nucleon Scattering at 11.75-GeV/c

We have measured the left-right asymmetry for the inclusive production of ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, ${K}^{\ifmmode\pm\else\textpm\fi{}}$, and protons in proton-proton and proton-deuteron collisions at 11.75 GeV/c. The measurements, utilizing the polarized proton beam at the Argonne zero-gradient synchrotron, cover a wide range of kinematic variables [$u$ between 0.6 and -1.5 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$ and $x$ between 0.1 and 0.9 for meson production, $t$ between -0.2 and -2.0 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$ and $x$ between -0.25 and 0.75 for proton production]. There is considerable angular structure in the pion-production data but not in the kaon or proton processes. Proton production alone is clearly sensitive to the isotopic spin of the target particle. A simple phenomenological model of baryon-exchange dominance successfully relates the inclusive pion asymmetries to the asymmetries in backward pion-nucleon elastic scattering. A triple-Regge model for the inclusive proton asymmetries is also discussed.
Linear position sensing by light exchange between two lossy waveguides

Optical position sensors have gained wide popularity in several segments of theindustry over the past few years. They offer a number of advantages overconventional types of sensors such as linear variable differential transformer(LVDT) and potentiometric devices. Specific advantages include immunity to
Low heat flow inferred from >4 Gyr zircons suggests Hadean plate boundary interactions

The first 600 million years or so of the Earth's history (the Hadean Eon) remain poorly understood, largely because there is no rock record dating from that era. Ancient zircons from that time period are, however, resistant minerals that can potentially provide insights into the conditions on the Earth at that time. Mark Harrison and colleagues now present an examination of inclusion assemblages in Hadean zircons from Jack Hills, Western Australia, which constrain the magmatic formation conditions to about 700°C and 7 kbar. This result implies a near-surface heat flow about three to five times lower than estimates of global Hadean heat flow. As the only site of magmatism on modern Earth that is characterized by heat flow of a quarter of the global average is above subduction zones, the authors suggest that the magmas from which the Jack Hills Hadean zircons crystallized, formed largely in an underthrust environment, perhaps similar to modern convergent margins. An examination of inclusion assemblages in Hadean zircons from Jack Hills (Western Australia) is presented, which constrain the magmatic formation conditions to about 700 °C and 7 kbars. This result implies a near-surface heat flow about 3–5 times lower than estimates of global Hadean heat flow. As the only site of magmatism on modern Earth that is characterized by heat flow of about one-quarter of the global average is above subduction zones, it is suggested that the magmas from which the Jack Hills Hadean zircons crystallized were formed largely in an underthrust environment, perhaps similar to modern convergent margins. The first ∼600 million years of Earth history (the ‘Hadean’ eon) remain poorly understood, largely because there is no rock record dating from that era. Detrital Hadean igneous zircons from the Jack Hills1, Western Australia, however, can potentially provide insights into the conditions extant on our planet at that time. Results of geochemical investigations2,3,4,5,6,7,8,9,10,11,12,13 using these ancient grains have been interpreted to suggest the presence of a hydrosphere2,3,4,7,8 and continental crust9,10 before 4 Gyr. An underexploited characteristic of the >4 Gyr zircons is their diverse assemblage of mineral inclusions14,15,16,17. Here we present an examination of over 400 Hadean zircons from Jack Hills, which shows that some inclusion assemblages are conducive to thermobarometry. Our thermobarometric analyses of 4.02–4.19-Gyr-old inclusion-bearing zircons constrain their magmatic formation conditions to about 700 °C and 7 kbar. This result implies a near-surface heat flow of ∼75 mW m-2, about three to five times lower than estimates of Hadean global heat flow. As the only site of magmatism on modern Earth that is characterized by heat flow of about one-quarter of the global average is above subduction zones, we suggest that the magmas from which the Jack Hills Hadean zircons crystallized were formed largely in an underthrust environment, perhaps similar to modern convergent margins.
Anharmonic potential functions for the out-of-plane modes of CH2X radicals

Abstract First-order perturbation theory is used to calculate mixed harmonic-quartic ground state potential functions for the out-of-plane deformations of the CH2X (X = Cl, Br, I) radicals. The calculated functions are then contrasted to the harmonic potential functions and used to confirm the observed isotopic shifts for isotopic molecules. For CH3 and CH2X radicals the quartic constants are large and important contributors to the potential energy.
Factors influencing the use of breast reconstruction postmastectomy: a National Cancer Database study.

Abstract BACKGROUND: Advances in surgical techniques and changes in our understanding of the biology of breast cancer have made immediate or early breast reconstruction a viable option for the majority of women with breast cancer. Little is known about national patterns of use of reconstruction. This study was undertaken to determine national patterns of care and factors that influence the use of breast reconstruction. STUDY DESIGN: A large convenience sample reported to the National Cancer Data Base was studied. Patients coded as undergoing mastectomy between 1985 and 1990 (n = 155,463) and between 1994 and 1995 (n = 68,348) were evaluated. The use of reconstruction in the two time periods was compared, and patient and tumor factors influencing the use of the procedure were compared. RESULTS: Between 1985 and 1990, 3.4% of mastectomy patients had early or immediate reconstruction, increasing to 8.3% in 1994–5. Patient age, income, geographic location, type of hospital where treatment occurred, and tumor stage all influenced the use of reconstruction in univariate analysis. In multivariate analysis, patients age 50 or under had a 4.3-fold greater likelihood of having reconstruction than their older counterparts. Patients with ductal carcinoma in situ were twice as likely as those with invasive cancer to have reconstruction. Family income of $40,000 or more (Odds Ratio 2.0), ethnicity other than African-American (Odds Ratio 1.6), surgery in a National Cancer Institute-designated cancer center (Odds Ratio 1.4), and surgery in a geographic region other than the Midwest or South (Odds Ratio 1.3) remained significant predictors of the use of reconstruction in multivariate analysis. CONCLUSIONS: Breast reconstruction is an underused option in breast cancer management. Predictors of the use of reconstruction do not reflect contraindications to the procedure, and indicate the need for both physician and patient education.
Storage of Spatial Information by the Maintenance Mechanism of LTP

Analogous to learning and memory storage, long-term potentiation (LTP) is divided into induction and maintenance phases. Testing the hypothesis that the mechanism of LTP maintenance stores information requires reversing this mechanism in vivo and finding out whether long-term stored information is lost. This was not previously possible. Recently however, persistent phosphorylation by the atypical protein kinase C isoform, protein kinase Mzeta (PKMz), has been found to maintain late LTP in hippocampal slices. Here we show that a cell-permeable PKMz inhibitor, injected in the rat hippocampus, both reverses LTP maintenance in vivo and produces persistent loss of 1-day-old spatial information. Thus, the mechanism maintaining LTP sustains spatial memory.
On the Extent of Dominance of Asymptotic Elastodynamic Crack-Tip Fields: Part II—Numerical Investigation of Three-Dimensional and Transient Effects

In Part I of this paper, the question of the extent of dominance of the mode I asymptotic elastodynamic crack-tip field (the K d I -field) was studied experimentally. Here, the results of two and three-dimensional elastodynamic finite element simulations of the drop-weight experiments are reported. The load records as obtained from the impact hammer and supports of the drop-weight loading device were used as boundary tractions in the numerical simulations. For the laboratory specimen studied, the results of the simulations indicate that the asymptotic elastodynamic field is not an adequate description of the actual fields prevailing over any sizeable region around the crack tip. This confirms the experimental results of Part I which showed that three-dimensional and transient effects necessarily have to be taken into account for valid interpretation of experimental results.
Epidemiology of Lindane Exposures for Pediculosis Reported to Poison Centers in Texas, 1998–2002

Background: Lindane (gamma‐benzene hexachloride), commonly used as a treatment for pediculosis, has been associated with adverse reactions and has recently undergone increased regulation. Objective: We sought to describe the patterns of a large number of lindane exposures reported to poison centers in Texas during 1998–2002. Methods: Data on all lindane exposures for pediculosis reported to the Texas Poison Center Network were analyzed. Results: There were 528 reported human exposures to lindane for pediculosis. The incidence of lindane exposures has decreased by 52% from 1998 to 2002. Misuse or abuse of lindane was reported in at 7least 87% of the cases. Of those cases with a known patient age, 45% were less than age 6 yrs, 23% age 6–19 yrs, and 32% over age 19 yrs. Female patients accounted for 55% of reported cases. Of those cases with a known medical outcome, 61% reported no effects. The most frequently reported symptoms were vomiting, nausea, and ocular irritation or ocular pain. Conclusion: The numb...
Long-term Outcomes of Cytomegalovirus Retinitis in the Era of Modern Antiretroviral Therapy: Results from a United States Cohort.

Purpose To describe the long-term outcomes of patients with cytomegalovirus (CMV) retinitis and AIDS in the modern era of combination antiretroviral therapy. Design Prospective, observational cohort study. Participants Patients with AIDS and CMV retinitis. Methods Immune recovery, defined as a CD4+ T-cell count >100 cells/μl for ≥3 months. Main Outcome Measures Mortality, visual impairment (visual acuity Results Patients without immune recovery had a mortality of 44.4/100 person-years (PYs) and a median survival of 13.5 months after the diagnosis of CMV retinitis, whereas those with immune recovery had a mortality of 2.7/100 PYs ( P Conclusions Among persons with CMV retinitis and AIDS, if there is immune recovery, long-term survival is likely, whereas if there is no immune recovery, the mortality rate is substantial. Although higher than the rates in the population not infected by human immunodeficiency virus, the rates of bilateral visual impairment and blindness are low, especially when compared with rates in the era before modern antiretroviral therapy.
Association of human papillomavirus with penile carcinoma: A study using polymerase chain reaction and in situ hybridization

Although carcinoma of the uterine cervix has been shown to be strongly associated with human papillomavirus (HPV) infection, a sexually transmitted disease, similar detailed data are lacking in penile carcinoma. To determine the association of HPV with penile carcinoma, we examined 30 specimens of penile carcinoma from 23 patients by the highly sensitive polymerase chain reaction (PCR) and in situ hybridization assays. We also examined nonneoplastic penile foreskins from 20 adults using the polymerase chain reaction assay. Human papillomavirus type 16 genome was found in 15 patients (65%), HPV type 30 was found in three (13%), and HPV type 6/11 was found in two (9%). These HPV types were not detected in any of the nonneoplastic foreskins. As in cervical carcinoma, HPV, particularly type 16, is strongly associated with penile carcinoma and may play an etiologic role in the development of this neoplasm.
More than Just Test Scores.

Around the world we hear considerable talk about creating world-class schools. Usually the term refers to schools whose students get very high scores on the international comparisons of student achievement such as PISA or TIMSS. The practice of restricting the meaning of exemplary schools to the narrow criterion of achievement scores is usually premised on the view that test scores are closely linked to the provision of a capable labour force and competitive economy. In fact, the measured relationships between test scores and earnings or productivity are modest and explain a relatively small share of the larger link between educational attainment and economic outcomes. What has been omitted from such narrow assessments are the effects that education has on the development of interpersonal and intrapersonal skills and capabilities that affect the quality and productivity of the labour force. This article provides evidence on some of these relationships, on the degree to which the non-cognitive effects of schooling contribute to adult performance, and on the evidence that deliberate school interventions can influence non-cognitive outcomes. It concludes with the view that the quest for world-class schools must encompass a range of human development characteristics that extend considerably beyond test scores.
A method for gentle lysis of Streptococcussanguis and Streptococcusmutans

Summary Methods have been developed to gently lyse strains of Streptococcus sanguis and Streptococcus mutans . For S. sanguis , the procedure involves: 1) acetylation of the cells; 2) exposure of the cells to high concentrations of lysozyme in the presence of a phosphate-sucrose buffer and 3) lysis of the cells with Sarkosyl. For S. mutans glycerol is used as a stabilizer instead of sucrose and dextranase is added along with lysozyme. Data are presented to indicate that 5 strains of each species are lysed by more than 60%. Using the lysing procedure developed for S. mutans , we were able to identify the plasmid of S. mutans LM7 by dye- CsCl and sucrose density centrifugation.
Prostaglandin E2 modulation of vascular endothelial growth factor production in murine macrophages

Abstract We have previously shown that dietary ( n -3) fatty acids decrease mammary tumor vascularization and PGE 2 production. One possible mechanism may be the modulation of vascular endothelial growth factor (VEGF) production by PGE 2 . Macrophages are major producers of VEGF, and thus we assessed the role of PGE 2 in vitro and in vivo on their VEGF production. When added to macrophages, pharmacological (10 −7 M) but not physiological (10 −9 to 10 −11 M) concentrations of PGE 2 increased VEGF mRNA and protein levels. That increased expression was relatively rapid and sustained up to 8 hrs, but declined by 24 hrs. Similarly, dibutryl cAMP increased production of VEGF protein which was completely inhibited by H89. Addition of cAMP-elevating agents further potentiated the production of VEGF by PGE 2 . Next, ( n -3) and ( n -6) fatty acids were added to macrophages in vitro or provided in the diet. Macrophages of mice fed safflower oil ( n -6) had 2- to 4-fold greater copy number of VEGF transcripts after lipopolysaccarhide (LPS) stimulation compared to fish oil ( n -3). A decreasing trend was seen in LPS-induced VEGF secretion from macrophages in vitro after docosahexaenoic acid or eicosapentaenoic acid incubation compared to arachidonic acid. While pharmacological concentrations of PGE 2 modulate VEGF expression, physiological alterations did not alter VEGF protein production by macrophages.
Mediterranean Sacrifice: Dimensions of Domestic and Political Religion

Sacrifice is a ritual in which an offering (inducement) is rendered humanly irretrievable and ingestible, and then directed to some controlling higher personage (usually a deity) by someone lower in social status in order to have some life-effect. In the first-century Mediterranean, there were two major institutional variations of religion: political religion and domestic religion. Hence there was also political sacrifice and domestic sacrifice. In political sacrifice inducement is directed to the deity(ies) as king or lord; in kinships sacrifice inducement is directed to the deity(ies) as the god(s) of the ancestors, a sort of elder family member or as patron or powerful neighbor. Why the offering of animal, vegetable or mineral, rendered irretrievable and ingestible, should have effect depended on the the value of omnipotence as perceived within the radical ingroup/outgroup orientation of ancient Mediterranean societies that defined outgroup members as another species.
Theoretical studies of selected C60H2 and C70H2 isomers

Abstract Semi-empirical MNDO methods predict that 2 of 23 structurally distinct C 60 H 2 isomers and 4 of 143 C 70 H 2 isomers have particularly low heats of formation. These isomers represent either 1,2-addition across a 6:6-ring fusion or 1,4-addition across a 6-ring, with both hydrogens externally bound. Fully optimized ab initio structures are computed for these low-lying isomers at the Hartree—Fock level using 3-21G and 6-31G* basis sets. For C 60 H 2 , all three methods agree on the isomer ordering, and the lowest energy structure is also the only one that has been observed experimentally. The energy separations among the lowest four C 70 H 2 isomers are found to be quite small, but only the ab initio ordering is consistent with experimental results.
Estimating available molybdenum in biosolids-amended soil using iron-oxide impregnated filter paper*

Various extraction procedures have been used to characterize molybdenum (Mo) in soils, and attempts have been made to correlate the results with plant response. However, few of these studies attempted to characterize available Mo in biosolids-amended soils, and none used Fe-oxide impregnated filter papers as an availability index. The purpose of this study was to determine the potential of Fe-oxide impregnated filter papers to assess the availability of Mo in biosolids-amended soils, and compare the assessments with those offered by a popular chemical extraction method (acid ammonium oxalate) and total soil Mo (EPA Method 3050A). Soil and plant samples were obtained from a field study with bahiagrass (Paspalum notatum Flugge) as the test crop and analyzed for Mo. The grass was grown in a sandy Spodosol, amended with two Class A biosolids at three rates. Though the effect of biosolids addition on total soil Mo was visible in Year 1, it gradually disappeared with time. However, tissue Mo contents varied sig...
Codeword Design for Multiple-Access Precoded Ultra-Wideband Communication System

We propose a novel precoded UWB (PUWB) system designed for multiple access (MA) communications. In our design, we try to enable concentration of the received signal power from different users (synchronized) at different time slots, thus make the matched filter (MF) based multiuser detection eligible for optimal reception. The optimum code is constructed to maximize the output signal-to-interference ratio (SIR). Specifically, we formulate the codeword design problem into an orthogonal basis finding problem, and the Gram-Schmidt algorithm can be easily applied. Computer simulations demonstrate the satisfactory performance of the proposed system. Extended simulations also cover the effect of symbol length; the resolution of the feedback code message; the number of multiple users; as well as the realizations from different standardized UWB channel models.
Phenanthrene desorption from soil in the presence of bacterial extracellular polymer: observations and model predictions of dynamic beheavior

Abstract The extracellular polymer produced by a bacterium isolated from soil was employed in laboratory studies of desorption of a model polynuelear aromatic hydrocarbon (PAH), phenanthrene. The experimental results show that the selected extracellular polymer enhances the extent of release of soil-bound phenanthrene. A kinetic model was developed as an aid in interpreting the alterations in phenanthrene desorption resulting from polymer addition. The model employs a statistical gamma ( γ ) distribution to describe spectrum of rate constants for transfer of phenanthrene from soil to water, and assumes instantaneous binding of phenanthrene to polymer and of polymer to the test soil. The relevant distribution coefficients and statistical parameters of the γ distribution needed for the model were evaluated in independent experiments. Using these measured parameters, the model provides a satisfactory independent prediction of phenanthrene release from soil to aqueous phase at two test polymer concentrations, 50 mg TOC/L and 100 mg TOC/L. The success of the independent model predictions suggests a mechanism for the influence of extracellular polymer on phenanthrene desorption. The intrinsic, soil-specific, rate constants for solid to solution transfer of phenanthrene do not appear to be changed by bacterial polymer. Instead, polymer binding of phenanthrene in solution results in an increase in driving force for desorption by decreasing the solution concentration of the free, unbound, PAH molecule.
Prosthetic aortic valve replacement complicated by diphtheroid endocarditis and aortopulmonary fistula.

Despite routine antibiotic prophylaxis and improvements in the design and techniques of implantation, endocarditis and disruption of the intracardiac prosthetic valves continue to be a real threat. Adequate control of infection with antibiotics or successful replacement of the infected prosthesis have been rare. Early diagnosis, specific antibiotic therapy, and surgical intervention offer the only hope of salvage of such patients.
Enzymic removal of 5-methylcytosine from DNA by a human DNA-glycosylase

Abstract DNA 5-methylcytosine is a major factor in the silencing of mammalian genes; it is involved in gene expression, differentiation, embryogenesis and neoplastic transformation. A decrease in DNA 5-methylcytosine content is associated with activation of specific genes. There is much evidence indicating this to be an enzymic process, with replacement of 5-methylcytosine by cytosine. We demonstrate here enzymic release of 5-methylcytosines from DNA by a human 5-methylcytosine-DNA glycosylase activity, which affords a possible mechanism for such replacement. This activity generates promutagenic apyrimidinic sites, which can be related to the high frequency of mutations found at DNA 5-methylcytosine loci. The recovery of most released pyrimidines as thymines indicates subsequent deamination of free 5-methylcytosines by a 5-methylcytosine deaminase activity. This prevents possible recycling of 5-methylcytosine into replicative DNA synthesis via a possible 5-methyl-dCTP intermediate synthesized through the pyrimidine salvage pathway. Taken together, these findings indicate mechanisms for removal of 5-methylcytosines from DNA, hypermutability of DNA 5-methylcytosine sites, and exclusion of 5-methylcytosines from DNA during replication.
Elementary divisors of graphs and matroids

New integer invariants of a graph G, introduced by U. Oberst, are obtained as the elementary divisors of the Laplacian matrix of G. The theory of elementary divisors is developed in the context of regular matroids. It is shown that the elementary divisors of a graph are actually invariants of its underlying matroid. Regular matroids, in turn, are related to lattices in euclidean space, and this leads to methods for computing the elementary divisors. Several properties of the elementary divisors of graphs are proved and the problem of how well these invariants distinguish between graphs is addressed.
On computing graph closures

Abstract The closure of a graph G of n vertices is obtained from G by recursively joining pairs of non-adjacent vertices whose degree sum is at least n until no such pair remains. We give an efficient algorithm to compute the closure using F -heaps. We also define the general closure of a graph and show that computing the general closure is P-complete with respect to log-space transformations.
Taurine efflux, band 3, and erythrocyte volume of the hagfish (Myxine glutinosa) and lamprey (Petromyzon marinus)

Hypoosmotic stress in skate RBC causes cell swelling followed by the release of solutes (osmolytes) to bring about a regulatory volume decrease (RVD). The β-amino acid, taurine, is a primary osmolyte in RVD of skate RBC. Taurine efflux is inhibited by stilbene disulfonates and other inhibitors of the anion exchanger, band 3, suggesting that band 3 is involved in the release of taurine during RVD in skate RBC. Since RBC of the cyclostomes, hagfish and lamprey, are reported to be deficient in band 3, we examined taurine efflux, quantity of band 3, and volume response in these RBC. There was no significant increase in taurine efflux when hagfish RBC were exposed to hypoosmotic medium, and the rate of taurine efflux in these RBC was markedly lower than that in skate RBC. Hagfish RBC plasma membranes show only 11% of the level of 3H2DIDS bound to skate RBC membranes. In addition, DIDS-sensitive sulfate exchange is much lower in hagfish compared with skate RBC. Similarly, lamprey RBC showed little taurine efflux compared with skate, and the amount of 3H2DIDS binding to these RBC membranes was 24% that of skate. Finally, although both hagfish and lamprey RBC swell in hypoosmotic medium, the lamprey cells show an RVD while the hagfish cells do not. Thus, in the RBC of the two cyclostomes, one showing an RVD and the other not, low band 3 is associated with low volume-activated taurine efflux. These results support the hypothesis that band 3 is involved in volume-activated taurine efflux. © 1992 Wiley-Liss, Inc.
Reflectivity measurements of coupled collective cyclotron excitation-longitudinal optical phonon modes in polar semiconductors

Abstract The magnetoreflection of n-type InAs has been measured in the far infrared region near the optical phonon frequency for both the Voigt and Faraday geometries. Such measurements illustrate the different possible types of cyclotron, plasmon, and phonon interactions which can occur.
Molecular Dynamics Potential of Mean Force Calculations: A Study of the Toluene−Ammonium π-Cation Interactions

We have examined the interaction between the ammonium cation and the aromatic face of toluene in water, by means of potential of mean force (PMF) calculations. Considering that (i) typical two-body additive molecular mechanical models cannot represent the energetics of π-cation interactions accurately and (ii) employing nonadditive force fields increases the computational effort significantly, we have incorporated a short-range “10−12” term in our potential function, ensuring that the magnitude of the attraction between ammonium and toluene reproduces the value estimated from high-level quantum mechanical calculations. Interestingly, the PMF curve generated in water clearly demonstrates that association is favorable in a polar aqueous medium, with a minimum of the free energy equal to ca. 3 kcal/mol, and an association constant of 6.5 M-1consistent with experimental data on related π-cation systems. This association appears to be even stronger when the approach of ammonium toward the toluene ring is axial...
Carbon reduction in triethylarsenic-grown GaAs films using chemically activated arsine as a co-reagent

N-type gallium arsenide films grown from triethylarsenic (Et3As) and trimethylgallium (Me3Ga) are generally of poor quality (μ77K(max) = 16,100 cm2/V-s) and are severely contaminated with carbon (>1018 cm−3), whereas films grown using a mixture of triethylarsenic and arsine (AsH3) with Me3Ga are typically of high purity (β77K(max) = 60,000 cm2/V-s) and contain significantly reduced carbon levels (~mid-1015 cm-3). These differences in film purity are due to the inherent growth chemistry of each reagent mixture. The respective growth chemistries of these reagent systems have been inferred from a series of decomposition experiments carried out under pseudo-growth conditions, and the differences in growth chemistry are consistent with the differences in corresponding epilayer purity. Triethylarsenic appears to decompose primarily via a bond homolysis reaction to generate alkyl-containing radical species, which can react with a growing GaAs epilayer to cause severe carbon contamination. In the Et3As/AsH3 coreagent system, the Et3As reagent decomposes to produce these alkyl-containing radical intermediates, but they then apparently react further with the arsine co-reagent to generate reactive arsenic hydride radicals under relatively facile conditions. These reactive arsenic-hydride radical species can contribute to the GaAs growth process without introducing carbon into the resultant films.
Optimization of an Aircraft Power Distribution Subsystem

A mathematical optimization problem is formulated to design several components of an electrical power distribution system for next-generation aircraft. A simple interconnected system consisting of an input e lter and a dc‐dc buck converter is used as the prototype for the optimization demonstration. The components are designed for minimum weight, subject to performance, stability, and peak voltage constraints. Optimized designs for each of the individual subsystems and for the integrated system are presented. It is shown that there is an interaction between thee lterdesign problem and theconverterdesign problem and thatweightimprovementscanbeobtained by considering these interactions. The optimization methodology described enables designers to obtain optimized electric power subsystem designs in a time-efe cient manner.
An objective snow profile comparison method and its application to SNOWPACK

Abstract With the increasing use of numerical models predicting the snow cover status, the need for a simple and standardized evaluation procedure arises. We present such a method that compares numerical model profiles with snow pit profiles and provides a quantitative statistical agreement–disagreement measure. The method can also be used to compare several model profiles with each other. The first step of the method is the mapping of the model profile layers onto the layers of the observed profile. This mapping is necessary to adjust for deviating total snow depth and shifted positions of the layers. Following the mapping, the individual profile parameters such as grain type, grain size, liquid water content, temperature and density are compared. The result of the comparison is a score between 0 (profiles show no agreement) and 1 (profiles are identical) for each parameter. The parameter scores can be combined to give an overall profile score between 0 and 1. The method facilitates evaluation studies and allows to quantify improvements made in the modeling of processes in the snow cover. This is illustrated by analyzing a simulated profile at an IMIS (German: Interkantonales Mess-und Informations System) automatic snow and weather station with an observed, detailed snow pit profiles from the Swiss Alps. The agreement score for the parameter grain type increased from 0.3 to 0.7 after introducing an additional grain type in the simulation. In addition, the scores were calculated for two observation stations in the Swiss Alps for a whole winter season and it was detected that for most of the winter an overall agreement score between SNOWPACK simulation and snow pit profile of approximately 0.8 is reached. The temperature regime is modeled best and most difficulties are encountered with grain type. An important result is further that the energy balance processes at the beginning of the spring melt season has to be improved.
Coexisting Kinetically Distinguishable Forms of Dialkylglycine Decarboxylase Engendered by Alkali Metal Ions

The pyridoxal phosphate (PLP) dependent enzyme dialkylglycine decarboxylase (DGD) specifically binds alkali metal ions near the active site. Large ions (Rb + ,K + ) activate the enzyme while smaller ones (Na + ,L i + ) inhibit it. Crystallographic results have shown that DGD undergoes a metal ion size dependent structural switch (Hohenester, E., Keller, J. W., and Jansonius, J. N. (1994) Biochemistry 33, 13561), but no evidence for multiple conformations in crystalline DGD was obtained. Here, evidence is presented that DGD-K + in solution exists in two conformations differing in catalytic competence. Initial rate traces for DGD-K + exhibit a high degree of curvature due to decreasing activity over time. DGD remains tetrameric under the assay conditions as demonstrated by gel filtration experiments, arguing against the possibility of subunit dissociation as the source of activity loss. Likewise, the mass spectrum of DGD shows a single covalent form. A hysteretic model that assumes two slowly interconverting enzyme forms accounts well for the initial rate data when kinetic parameters from biphasic pre-steady-state kinetics are employed. The fit of the model to the data yields an estimate of 59 ( 1% for the fast form. A cooperative model cannot account for the data. Double reciprocal plots for coenzyme binding to DGD exhibit two linear phases. Similarly, two kinetic phases are observed in PLP association kinetics. The substitution of Na + or Rb + for K + alters the steady-state kinetic parameters of DGD. Preincubation of DGD-K + with the competitive inhibitor 1-aminocyclopropane-1-carboxylate (ACC) lowers both kcat and KAIB apparently by drawing the enzyme toward the less active, tighter binding form observed in the pre- steady-state kinetics. These results suggest that the structure of the protein around the alkali metal ion determines the conformational distribution. The transamination reaction with L-alanine was coupled in the pre-steady-state to the LDH-catalyzed oxidation of NADH. This experiment yields an estimate of 68 ( 4% for the fast form, in agreement with the hysteretic fit to the steady-state data. The reaction of DGD with dithiobis(nitrobenzoate) was used to probe the preexisting forms of DGD. Preincubation of DGD with ACC, like the exchange of Na + for K + , shifts the conformational distribution, in agreement with the steady-state kinetics. These experiments clearly demonstrate that DGD is a hysteretic enzyme whose conformational distribution is controlled by the identity of the alkali metal ion bound near the active site, and that cooperativity does not play a role in catalysis or regulation.
Neutron Capture Cross Section of 239Pu

Abstract The Detector for Advanced Neutron Capture Experiments (DANCE) has been used to measure the 239 Pu(n, γ ) cross section from 10 eV to the keV region. Three experimental run conditions were used to characterize the prompt fission γ -ray spectrum across the entire energy regime, measure the cross section in the resolved resonance region, and obtain necessary count rate well into the keV region. The preliminary cross sections are in good agreement with current evaluations from 10 eV to 80 keV.
Axillary Dissection Can Be Avoided in the Majority of Clinically Node-Negative Patients Undergoing Breast-Conserving Therapy

Background The extent to which ACOSOG Z0011 findings are applicable to patients undergoing breast-conserving therapy (BCT) is uncertain. We prospectively assessed how often axillary dissection (ALND) was avoided in an unselected, consecutive patient cohort meeting Z0011 eligibility criteria and whether subgroups requiring ALND could be identified preoperatively.
Amino acid composition and C-terminal sequence of foot-and-mouth disease virus protein

Abstract The amino acid composition of foot-and-mouth disease virus (FMDV) protein from type A virus, strain 119, and sequence of amino acids at the C-terminus were determined. Previous evidence from disc gel electrophoresis and gel filtration experiments has indicated that the protein of FMDV is built up from a homogeneous polypeptide. The amino acid composition of the protein agreed closely with that determined earlier on whole virus, where a large correction factor for glycine was necessitated. The amino acids with basic, hydroxy, acidic, and hydrocarbon (including tyrosine) side chains comprised about 12, 17, 19, and 42% of the protein, respectively. Methionine, tryptophan, and half-cystine were present in the least amounts, approximately 1.5, 1.0, and 0.8%, respectively. Analysis showed the half-cystine to exist in the protein coat in situ entirely as cysteine. The rate of release of amino acids from the protein by carboxypeptidase A together with hydrazinolysis of the protein indicated as C-terminal sequence of —(Val, Asp, Thr, Asn, Phe, Glu, Gly)-Ser-Ala-Leu-Gln, the sequence within the parentheses being uncertain. An extinction coefficient, E 1% 276m μ = 11.1, calculated for the protein from quantitative amino acid analysis, was identical to that determined earlier by quantitation of the protein mass.
A Fast Number‐theoretic Transform Approach to a GPS Receiver

This paper describes the application of the Fast Number-theoretic Transform (FNT) to the processing of GNSS signals. This FNT is an alternative to Fast Fourier Transform (FFT) techniques and efficiently provides bit-for-bit identical results to a traditional time-domain correlator without the need for word-length growth or the quantization of irrational complex roots of unity. We document a prototype single channel GPS C/A code receiver with a continuously operating correlator that computes hundreds of lags. The design is implemented with an inexpensive Field Programmable Gate Array (FPGA) programmed to implement the FNT. As an initial application, we present a multipath investigation using this receiver in which we were able to localize and then identify the source of the multipath signal.
Fault-tolerance in parallel architectures with crosspoint switches

Based on an existing IBM/370 switch connected parallel processor (SCPP) prototype implementation, conceptual enhancements in the design for continuous availability are described. These enhancements include the user-specifiable two- to three-fold concurrent execution of processes on nonsynchronized processing units (PUs). The output produced by these processes is compared by software or hardware means. The asynchronism of the execution allows the detection of context-dependent software failures in addition to the detection of hardware errors. These design advances encompass novel hardware and software features aimed at achieving continuous system operation as well as superior information integrity at an improved cost/performance ratio, facilitating a proven crosspoint switch intercommunication mechanism of the SCPP. >
Combining high-order necessary conditions for optimality with nonsmoothness

We present a version of the Pontryagin maximum principle valid for systems of flows rather than for systems governed by ordinary differential equations. The flow maps are required to be differentiate in a generalized sense (using the theory of "generalized differential quotients") which is much weaker than ordinary differentiability and allows the "differentials" to be sets of linear maps rather than single linear maps. The resulting conditions apply to control dynamics with a right-hand side that needs not be smooth, or even Lipschitz, and could even be discontinuous. This is so because the usual adjoint equation, in which there occur derivatives of the reference vector field with respect to the state, is replaced by an integrated form. This form only involves differentials of the reference flow maps, and therefore makes sense as long as these flow maps are differentiable, which can happen even when the reference vector field itself fails to be Lipschitz or even continuous. The resulting "integrated adjoint equation" gives rise to "adjoint vectors" that need not be absolutely continuous, and could be discontinuous and unbounded. Furthermore, this integrated adjoint equation relates the values of the adjoint vector on intervals that could be disjoint and contain singularities in between. This makes it possible to establish necessary conditions for an optimum that yield a global adjoint vector that satisfies various nonsmooth conditions everywhere and at the same time satisfies extra "high-order" requirements, such as the Goh condition, on intervals where the dynamics is sufficiently smooth.
An iterative method to compensate for the interpolation distortion

The author shows that iterative techniques can be used to compensate for sample-and-hold or, in general, interpolation distortion. It is proven that this iterative method converges to the true signal in the limit. The simulation results of the iterative technique are compared to results of the modular method. Simulation results show that the iterative method is a powerful tool for reducing distortion compared to other well-known techniques. >
Dinitrogen production from nitrite by a Nitrosomonas isolate

A chemolithotrophic ammonium-oxidizing bacterium that was able to reduce 15NO2− to 15N2 (m/z 30) while oxidizing ammonium under conditions of oxygen stress was isolated from stream sediments. Energy was derived from ammonium oxidation, as evidence by growth, with CO2 serving as the sole C source. The organism was a gram-negative, motile, short rod that failed to grow either aerobically or anaerobically in heterotroph media. The organism was identified as a Nitrosomonas sp.