cssi/SciSciGPT-SciSciNet huggingface dataset:
Interaction of Cd and Zn with biologically important ligands characterized using solid-state NMR and ab initio calculations.

For the first time, coordination geometry and structure of metal binding sites in biologically relevant systems are studied using chemical shift parameters obtained from solid-state NMR experiments and quantum chemical calculations. It is also the first extensive report looking at metal−imidazole interaction in the solid state. The principal values of the 113Cd chemical shift anisotropy (CSA) tensor in crystalline cadmium histidinate and two different cadmium formates (hydrate and anhydrate) were experimentally measured to understand the effect of coordination number and geometry on 113Cd CSA. Further, 13C and 15N chemical shifts have also been experimentally determined to examine the influence of cadmium on the chemical shifts of 15N and 13C nuclei present near the metal site in the cadmium−histidine complex. These values were then compared with the chemical shift values obtained from the isostructural bis(histidinato)zinc(II) complex as well as from the unbound histidine. The results show that the isotr...
The Lives of Professional Classical String Players: A Selective Annotated Bibliography

Classical performer biographies afford the reader the unique privilege of learning about the personal histories, daily lives, and rituals of those who regularly enthrall audiences when they take the stage. Often there are offstage dramas, family, social, environmental, or even political challenges that musicians must overcome to achieve their professional goals. While the printed format of published biographies may still be considered the norm, biographical sketches of classical musicians are now available on personalized web sites, blogs and online interviews. The area of biography of classical string performers is particularly extensive and worthy of review. This selective annotated bibliography explores the depth and variety of offerings in the area of classical string performer biographies.
Structure and permeability of goblet cell tight junctions in rat small intestine

Two major cell types, goblet and absorptive cells, dominate the epithelial lining of small intestinal villi. We used freezefracture replicas of rat ileal mucosa to examine the possibility that tight junction structure, known to relate to transepithelial resistance, might vary with cell type. Tight junctions between absorptive cells were uniform in structure while those associated with villus goblet cells displayed structural variability. In 23% of villus goblet cell tight junctions the strand count was less than 4 and in 30% the depth was less than 200 nm. In contrast, only 4% of absorptive cell tight junctions had less than 4 strands and only 9% had depth measurements less than 200 nm. Other structural features commonly associated with villus goblet cell tight junctions but less commonly with absorptive cell tight junctions were: deficient strand cross-linking, free-ending abluminal strands, and highly fragmented strands. Bothin vivo ileal segments and everted loops were exposed to ionic lanthanum. Dense lanthanum precipitates in tight junctions and paracellular spaces were restricted to a subpopulation of villus goblet cells and were not found between villus absorptive cells. After exposure of prefixed ileal loops to lanthanum for 1 hour, faint precipitates of lanthanum were found in 14% of tight junctions and paracellular spaces between absorptive cells compared to 42% of tight junctions and paracellular spaces adjacent to villus goblet cells. When tested in Ussing chambers, the methods used for lanthanum exposure did not lower transepithelial resistance. Everted loops exposed to ionic barium and examined by light microscopy showed dense barium precipitates in the junctional zone and region of the paracellular space of villus goblet cells but not in these regions between absorptive cells. However, the macromolecular tracers, microperoxidase, cytochromec and horseradish peroxidase, were excluded from both villus goblet cell and absorptive cell paracellular spaces inin vivo segments. These findings suggest that a subpopulation of villus goblet cells may serve as focal sites of high ionic permeability and contribute to the relatively low resistance to ionic flow which characterizes the small intestinal epithelium.
Predictions Of Unidirectional Irregular Wave Kinematics And Evolution

A numerical scheme is developed based on the hybrid wave model for the prediction of the short-distance wave evolution and kinematics of irregular waves. The hybrid wave model considers the interaction between the components in a wave field up to the second order of wave steepness. The numerical results have been extensively compared with three sets of laboratory wave elevation and kinematic measurements as well as the related predictions by linear random wave theory and its "stretching" and "extrapolation" modifications. The excellent agreement between the results of the hybrid wave model and the measurements confirms that the hybrid wave model is more accurate and more reliable than the other three methods, especially for steep and broad-banded wave trains.
Mechanism of age related macular degeneration

AMD is a poorly understood disease at this time. Since it is the leading cause of blindness in the elderly in the developed world, there is a pressing need for better treatment. Therefore, there is extensive ongoing research in both pathogenesis and therapy of AMD. Epidemiological studies have shown significant risk associated with increasing age and cigarette smoking, future studies may identify environmental risk factors though at present studies have been inconclusive. Genetic studies may identify subgroups of disease and thus help provide a selective approach to treatment. The vascular model of AMD may provide better understanding of the blood flow and post capillary resistance and help in early and newer intervention in the disease. Vascular endothelial growth factor has been extensively studied in choroidal neovascularization. It has been demonstrated in human and animal models of CNV and VEGF antagonists are currently in clinical trial. Extensive work is ongoing to prevent and treat CNV with antiangiogenic agents.
Small Group Work Climates: A Lag-Sequential Analysis of Group Interaction

This study examines procedural messages and group work habits of 20 three-person groups, 10 who preferred a tightly-structured work climate and 10 who preferred a free-associative work routine. The...
Mitochondrial Glutathione Depletion Reveals a Novel Role for the Pyruvate Dehydrogenase Complex as a Key H2O2-emitting Source Under Conditions of Nutrient Overload

Once regarded as a "by-product" of aerobic metabolism, the production of superoxide/H2O2 is now understood to be a highly specialized and extensively regulated process responsible for exerting control over a vast number of thiol-containing proteins, collectively referred to as the redox-sensitive proteome. Although disruptions within this process, secondary to elevated peroxide exposure, have been linked to disease, the sources and mechanisms regulating increased peroxide burden remain poorly defined and as such are difficult to target using pharmacotherapy. Here we identify the pyruvate dehydrogenase complex (PDC) as a key source of H2O2 within skeletal muscle mitochondria under conditions of depressed glutathione redox buffering integrity. Treatment of permeabilized myofibers with varying concentrations of the glutathione-depleting agent 1-chloro-2,4-dinitrobenzene led to a dose-dependent increase in pyruvate-supported JH2O2 emission (the flux of H2O2 diffusing out of the mitochondrial matrix into the surrounding assay medium), with emission rates eventually rising to exceed those of all substrate combinations tested. This striking sensitivity to glutathione depletion was observed in permeabilized fibers prepared from multiple species and was specific to PDC. Physiological oxidation of the cellular glutathione pool after high-fat feeding in rodents was found to elevate PDC JH2O2 emission, as well as increasing the sensitivity of the complex to GSH depletion. These findings reveal PDC as a potential major site of H2O2 production that is extremely sensitive to mitochondrial glutathione redox status.
The reaction of oxyhemoglobin with 1,1-diphenyl-2-picrylhydrazine and 2,2-diphenyl-1-picrylhydrazyl.

Abstract In an effort to elucidate the mechanism of the initiation reaction of the denaturation of oxyhemoglobin, I, to methemoglobin, II, by hydrazines, we have investigated by electron paramagnetic resonance, EPR, and visible spectrophotometry at 22°C, pH 7.4, the reaction of I with 1,1-diphenyl-2-picrylhydrazine, III, and 2,2-diphenyl-1-picrylhydrazyl, IV, in dimethylsulphoxide/buffer and methanol/buffer mixtures, these organic solvents included at a concentration of 10 v v % to render III and IV soluble while not causing appreciable denaturation of I. In both buffer mixtures, the results obtained were the same. For the I/III reaction mixtures, although the spectrophotometric data obtained showed denaturation to occur, there was no EPR evidence for formation of IV, contrary to expectation based on the chemical structure of III. The EPR observations on each I/IV reaction mixture showed a rapid decrease in IV signal intensity to a value that, depending on the initial reactant concentrations, was either below the detection limit or, when measurable, constant with time. The results of similar EPR measurements on analogous II/IV reaction mixtures were the same. These EPR results are compatible with the idea that IV forms a complex with the protein moiety of I and II, and show that the I/III reaction could yield IV and thus involve a one-electron transfer process.
Mechanism of decreased vascular response to angiotensin II in renal vascular hypertension

Mechanism of decreased vascular response to angiotensin II in renal vascular hypertension. Compared to many forms of hypertension, vascular reactivity to angiotensin II (AII) is decreased in the early phase of two–kidney, one clip (2-K, 1C) renovascular hypertension (RVH). To determine the role of the AII receptor, we examined vascular responsiveness and 125 I-AII binding to mesenteric artery membrane fractions after three weeks of 2-K, 1C RVH. Systolic blood pressure was 165 ± 8 in RVH and 105 ± 4mm Hg in controls, P 125 I-AH binding to mesenteric arteries was equal to or greater in RVH than controls at all concentrations of AIL Scatchard analysis revealed an increase in the total number of binding sites (B MAX ): 140.8 ± 6.3 in RVH versus 91.7 ± 6.5 fmol/mg in controls, P MAX = 136 ± 13.4 in RVH vs. 94 ± 9.4 fmol/mg in RVH + nephrectomy, P
Should remittances be taxed or subsidized

This paper analyzes the optimal nonlinear schedule of taxes and subsidies on remittances from emigrants. The analysis identifies conditions under which emigrants remitting small amounts of income face positive average and marginal subsidies on their remittances, whereas emigrants remitting relatively large amounts of income face positive marginal taxes. In this way, the tax system improves the distribution of income by indirectly taxing the “brain drain,” while simultaneously encouraging remittances that tend to go to low-income residents.
Behavioral and electrophysiological responses of female mice to male urine odors

Abstract Female mice of a strain in which the estrus cycle can be accelerated by urine odor from normal males but not from castrated males were tested for behavioral and electrophysiological responses to these odors. In behavioral tests, they spent more time sniffing tubes containing urine from normal males than those with urine from castrated males. In electrophysiological experiments, neurons in the olfactory bulb, preoptic area and lateral hypothalamus responded to these biologically significant odors. However, no neurons were observed that responded exclusively to urine odors and only a few neurons showed consistently different responses to the odors from normal and castrated males.
The Internet gambling conundrum: Extraterritorial impacts of U.S. laws on Internet businesses

Abstract Internet gambling is a significant commercial activity that has been successfully adapted to the online environment. The geographical transcendence of the Internet presents challenges for government regulation, which varies considerably. U.S. patrons have historically provided a significant portion of the Internet gaming market, despite a dubious legal status. The Unlawful Internet Gambling Enforcement Act (UIGEA) enacted in October 2006 clarifies the legal status otherwise imposed by state law by prescribing felony criminal status to the Act of receiving an Internet wager from a jurisdiction where such wagering is illegal. This article provides an analysis of the UIGEA and its effects on Internet gambling firms, as well as related businesses. Despite targeting gambling firms, this legislation may also assist in the prosecution of other firms through aiding and abetting liability. UIGEA also targets financial services providers, requiring additional safeguards to stop unlawful transactions destined for Internet gaming sites. Financial markets suggest that this legislation has reduced Internet gambling in publicly traded firms. However, the bill may also have the effect of enhancing investment capital flows for online gambling firms, due to clarification of the legal status for firms who are not targeting U.S. residents in violation of UIGEA. The ultimate result may depend on whether other nations follow suit in targeting extraterritorial business with domestic gambling patrons.
Self-assembly of surfactants and phospholipids at interfaces between aqueous phases and thermotropic liquid crystals

Abstract Recent studies have reported on the self-assembly of surfactants and phospholipids at interfaces between aqueous phases and thermotropic liquid crystals. These studies have been enabled by an experimental system that permits the preparation of stable and easily-imaged interfaces between liquid crystals and aqueous phases. The influence of the molecular structure of surfactants and their interfacial organization on the ordering of the liquid crystals has been revealed. Because the liquid crystals reorder on time-scales of seconds or less, the time-dependent behavior of the liquid crystals can be used to follow dynamic phenomena at these interfaces, including the adsorption and desorption of surfactants. At these same aqueous-liquid crystal interfaces, phospholipids have been shown to organize into assemblies that possess the mobility of biological membranes and are coupled to the order within the liquid crystal. Specific protein binding events and enzyme-catalyzed reactions at phospholipid-decorated interfaces of liquid crystals lead to changes in the organization of the phospholipids that are “reported” as ordering transitions in the liquid crystal.
Climbing fiber responses of cerebellar Purkinje cells to passive movement of the cat forepaw.

Summary The activity of cerebellar Purkinje cells during controlled and passive movement of the forepaw was studied in the cat. Burst responses characteristic of activation by climbing fibers were observed in Purkinje cells in lobules Vb and Vc of the cerebellar vermis and paravermis. The climbing fiber responses followed the onset of a movement with a latency ranging from 20 to 60 msec depending upon movement type and amplitude. Responsive Purkinje cells were localized in a well defined parasagittal strip very near the paravermal vein in lobules Vb and Vc. Cells within the responsive strip responded with identical response probabilities and latencies for any particular type of movement presentation. Responses were independent of starting paw position and direction of movement. Climbing fiber responses could be evoked by extremely small movements with most cells responding to displacements of 50 μm. The latencies and probabilities for climbing fiber responses were inversely related to movement amplitude with latencies as long as 80 msec for very small displacements.
A Review of Organic and Inorganic Biomaterials for Neural Interfaces

Recent advances in nanotechnology have generated wide interest in applying nanomaterials for neural prostheses. An ideal neural interface should create seamless integration into the nervous system and performs reliably for long periods of time. As a result, many nanoscale materials not originally developed for neural interfaces become attractive candidates to detect neural signals and stimulate neurons. In this comprehensive review, an overview of state-of-the-art microelectrode technologies provided fi rst, with focus on the material properties of these microdevices. The advancements in electro active nanomaterials are then reviewed, including conducting polymers, carbon nanotubes, graphene, silicon nanowires, and hybrid organic-inorganic nanomaterials, for neural recording, stimulation, and growth. Finally, technical and scientific challenges are discussed regarding biocompatibility, mechanical mismatch, and electrical properties faced by these nanomaterials for the development of long-lasting functional neural interfaces.
Skin under the sun: when melanin pigment meets vitamin D.

In this issue of Endocrinology, Saternus et al (1) present genetic evidence that the activity of pigmentation-related genes can affect serum levels of 25(OH)D in the cohort of 2790 Caucasian patients hospitalized for coronary angiography at the Ludwigshafen General Hospital in Germany. Specifically, variants of 11 from 29 investigated genes that included exocyst complex component 2 (EXOC2), tyrosinase (TYR), TYR-related protein type 1 (TYRP1) affected most serum 25(OH)D levels. Furthermore, the presence of 46 SNPs located in 16 pigmentary genes was associated with either increased or decreased levels of 25(OH)D calculated for total cohort of vitamin D-deficient/insufficient patients (mean, 17.3 ng/mL and median, 15.5 ng/mL) (1). Twelve of these SNPs located at the endothelin 1 (n 3), EXOC2 (n 1), microphtalmiaassociated transcription factor (MITF) (n 2), TYR (n 4), TYRP1 (n 1), and cAMP-dependent protein kinase catalytic subunit(n 1) genes reached the significance level after correction for multiple comparisons. Unfortunately, lack of detailed information on the pigmentary phenotype of the patients and on the correlation between analyzed SNPs and functional activity of the proteins prevents a conclusive analysis of the relationship between pigmentary or associated activities and serum levels of 25(OH)D, leaving significant room for speculations and further research. Melanin Is Securing the Skin Place Under the Sun
MINERAL CONTENT OF LOUISIANA WHITE-TAILED DEER

Water, lipid, and mineral composition were determined for metacarpals, phalanges, livers, and antlers from 219 free-ranging white-tailed deer (Odocoileus virginianus) collected on six properties in East Feliciana Parish, Louisiana (USA) to provide baseline data and to identify sources of composition variation. Metacarpal and phalangeal composition varied primarily with deer age; liver composition varied with deer sex.
Synthesis and Relative Thermal Stabilities of Diphenylamino- vs Piperidinyl-Substituted Bithiophene Chromophores for Nonlinear Optical Materials

Electrooptic poled polymers can be used in a variety of photonic applications involving the switching or modulation of light. These polymers contain second-order nonlinear optical chromophores that have been aligned by electric-field poling near the glass transition temperature of the polymer host. Loss of poling-induced alignment of the chromophores results in a decay of the macroscopic nonlinearity and presents an important issue that must be addressed if these materials are to have a commercial impact. Accordingly, researchers have attempted to incorporate chromophores into polymers with glass transition temperatures far in excess of the anticipated operating temperatures, such that over the lifetime of the devices the decay of chromophore alignment is minimized. This has created a need for chromophores that not only are very nonlinear but also have adequate thermal stability to survive the poling process which may occur at temperatures exceeding 200 °C. Accordingly, as part of our ongoing effort to develop chromophores for nonlinear optical applications we synthesized a series bithiophene-based chromophores (Figure 1) with the hope that they may have both high optical nonlinearity and good thermal stability. The donor−acceptor bithiophene chromophores have the advantage of having moderate aromatic stabilization in the ground state, making them more oxidatively stable than the analogous polyene chromophores and more polarizable than the analogous biphenyl chromophores. In addition, several reports in the literature demonstrated that protons α to the amine donor attenuate the thermal stability of other nonlinear optical chromophores. Therefore we examined the relative stability of compounds substituted with either piperidinyl or diphenylamino donors.
Antibody Response to Inactivated Influenza Vaccines of Various Antigenic Concentrations

Four inactivated influenza vaccines (containing the recommended antigens for the 1985-1986 influenza season) of various antigenic concentration levels were randomly administered to 140 study participants. The effect of the increasing antigen concentration resulted in significantly higher influenza hemagglutination inhibition (HI) antibody levels 3 weeks after vaccination for the A/H1N1 antigen but not for the A/H3N2 or B antigens. Also, at 3 weeks after vaccination, there were significantly lower antibody titer levels associated with increasing age for the A/H1N1 and B antigens (adjusting for the prevaccination antibody titer and antigen content).
Synthesis, characterization, and structural analyses of three high-coordination tetra-n-butylammonium lanthanide(III) complexes

Reactions of tetra-n-butylammonium thiocyanate with the appropriate lanthanide nitrate polyhydrate yield complexes of the general type [(n-C 4 H 9 ) 4 N] 3 [Ln(NCS) x (NO 3 ) y ]. [(n-C 4 H 9 ) 4 N] 3 [Pr(NCS) 2 (NO 3 ) 4 ] ( I ), [(n-C 4 H 9 ) 4 N] 3 [Nd(NCS) 4 (NO 3 ) 2 ] ( II ), and [(n-C 4 H 9 ) 4 N] 3 [Dy(NCS) 4 (NO 3 ) 2 ] ( III ) were crystallized from ethanol and characterized by single-crystal X-ray crystallography, IR spectroscopy, and other physical determinations. The coordination about the central lanthanide ion varied. For complex I , the geometric polyhedron is a bicapped square antiprism ( D 4 d ), while those for complexes II and III are best described as a dodecahedral prism ( D 2 d ). Details of the synthesis and selected bond distances and angles are presented and discussed.
Low-Temperature Solution Route to Macroscopic Amounts of Hydrogen Terminated Silicon Nanoparticles

A new solution route for preparing gram-scale, hydrogen terminated silicon nanoparticles is presented. Dimethoxyethane and diocytl ether have been used to prepare silicon nanoparticles via a solution reaction between sodium silicide and ammonium bromide. The reaction products are isolated as a clear yellow-orange solution and a dark black powder. Both the solution and the powder have been characterized.
Neutral copper cluster sputtering yields: Ne+ Ar+ and Xe+ bombardment

Abstract The sputtering of neutral metal clusters was investigated by measuring relative sputtering yields of copper clusters ejected from polycrystalline copper under 3.9 keV bombardment by Ne+, Ar+ and Xe+ ions at normal incidence. The yields of clusters from Ne4 bombardment were lower than those from Ar+ bombardment, and yields from Ar+ bombardment were lower than those from Xe+ bombardment. The sputtering yield ratios Ne+/Ar+ and Xe+/Ar+ were measured to be 0.56 and 1.08. The size distribution of the sputtered clusters can be fit by a power law dependence with exponents of −8.1, −8.2 and −6.2 for Ne+, Ar+ and Xe+, respectively. The similarity of the exponents of the Ne+ and AI+ power law fits indicates that the sputtering yields for these two primary ions are similar, while that for Xe+ is substantially higher, in contrast to the sputtering yield ratio data. The difference between the two measurements can be explained by assuming a systematic uncertainty in the sputtering yield ratio measurements that makes the measured ratios lower than the true values. Assuming a value at the high end of the experimental Ne+ sputtering yield range, the exponents of the power law fits exhibit a linear dependence on the total sputtering yield.
Reducing gender disparities in post-total knee arthroplasty expectations through a decision aid

Background Gender disparities in total knee arthroplasty utilization may be due to differences in perceptions and expectations about total knee arthroplasty outcomes. This study evaluates the impact of a decision aid on perceptions about total knee arthroplasty and decision-making parameters among patients with knee osteoarthritis.
Structure, Stability, and Electronic Interactions of Polyoxometalates on Functionalized Graphene Sheets

Polyoxometalates (H(3)PMo(12)O(40), H(3)PW(12)O(40), H(4)PMo(11)VO(40)) supported on oxygen- and alkyl-functionalized graphene sheets were investigated. Discrete molecular species were directly observed by electron microscopy at loadings below 20 wt.%. The interaction between the polyoxometalates and the graphene surface was found to significantly impact their vibrational spectra and a linear correlation between the frequency of the M-O(c)-M vibration and the dispersion was evidenced by FTIR. While bulk-like electronic properties were observed for small aggregates (2-5 nm), UV-vis spectroscopy and cyclic voltammetry revealed changes in the electronic structure of isolated molecular species as a result of their interaction with graphene. Because of the ability to disperse alkyl-functionalized graphene in a variety of polar and nonpolar solvents, the materials synthesized in this work provide an opportunity to disperse polyoxometalates in media in which they would not dissolve if unsupported.
Multiscale photoacoustic microscopy and computed tomography.

Photoacoustic tomography (PAT) is probably the fastest-growing area of biomedical imaging technology, owing to its capacity for high-resolution sensing of rich optical contrast in vivo at depths beyond the optical transport mean free path (~1 mm in human skin). Existing high-resolution optical imaging technologies, such as confocal microscopy and two-photon microscopy, have had a fundamental impact on biomedicine but cannot reach the penetration depths of PAT. By utilizing low ultrasonic scattering, PAT indirectly improves tissue transparency up to 1000-fold and consequently enables deeply penetrating functional and molecular imaging at high spatial resolution. Furthermore, PAT promises in vivo imaging at multiple length-scales; it can image subcellular organelles to organs with the same contrast origin — an important application in multiscale systems biology research.
Mirroring the real world in social media: twitter, geolocation, and sentiment analysis

In recent years social media has been used to characterize and predict real world events, and in this research we seek to investigate how closely Twitter mirrors the real world. Specifically, we wish to characterize the relationship between the language used on Twitter and the results of the 2011 NBA Playoff games. We hypothesize that the language used by Twitter users will be useful in classifying the users' locations combined with the current status of which team is in the lead during the game. This is based on the common assumption that "fans" of a team have more positive sentiment and will accordingly use different language when their team is doing well. We investigate this hypothesis by labeling each tweet according the the location of the user along with the team that is in the lead at the time of the tweet. The hypothesized difference in language (as measured by tfidf) should then have predictive power over the tweet labels. We find that indeed it does and we experiment further by adding semantic orientation (SO) information as part of the feature set. The SO does not offer much improvement over tf-idf alone. We discuss the relative strengths of the two types of features for our data.
Pyrolytic formation of 3-hydroxy-2-penteno-1,5-lactone from xylan, xylo-oligosaccharides, and methyl xylopyranosides

Abstract Xylan, xylotriose, and xylobiose were heated for 3 sec at 386 and 423° in helium as carrier gas. The major, volatile decomposition-products of the foregoing compounds were 3-hydroxy-2-penteno-1,5-lactone and 2-furaldehyde. Lactone formation also occurred on pyrolysis of methyl α- and β-D-xylopyranosides, although the yields of volatile products were very low, except for methanol, which was derived from the aglycon. The relative yield of the lactone decreased as the number of non-reducing xylopyranosyl residues in the molecule decreased. None of the lactone could be found in the pyrolyzate of D-xylose, whereas 2-furaldehyde was formed from all of the samples. These results suggest that 3-hydroxy-2-penteno-1,5-lactone is formed independent from the formation of 2-furaldehyde, and that the lactone arises from the non-reducing xylopyranosyl residues in the molecule. The results of dynamic thermal analyses of xylan, xylo-oligosaccharides, D-xylose, and methyl β-D-xylo-pyranoside are also reported.
Synthesis of Cyclopeptide Alkaloids by Cyclooligomerization of Dipeptidyl Oxazolines

Abstract Cyclodehydration of Cbz-valylthreonine methyl esters with Burgess reagent provides access to cis - and trans -oxazoline segments for cyclooligomerization reactions. The ratio of 12-, 18-, 24-, and larger-ring macrocycles obtained in this process is kinetically controlled and dependent on the relative stereochemistry of the backbone α-carbons. A network of bifurcated hydrogen bonds rigidifies the peptidyl oxazoline strand and positions the valine side chains in either pseudoaxial or pseudoequatorial orientations. In the former case, transannular strain prevents the formation of 12-membered cyclopeptide alkaloids. Several X-ray structures illustrate the conformational preferences in this family of marine natural product analogs.
Wave-optics description of amplified spontaneous emission.

Paraxial Maxwell-Bloch theory is used to describe amplified spontaneous emission (ASE) in strongly inverted media. Counterpropagation of waves coupled through gain saturation and diffraction, and pumping by a laser beam which propagates transverse to the amplifier are included in the treatment. The reactive part of the medium polarization is calculated by population-rate equations in the limit of rapid dephasing of the atomic dipoles. The spontaneous emission noise source needed for the numerical simulation of Maxwell's equations is derived from microscopic theory by coarse-graining, thereby establishing the compatibility of the spherically symmetric microscopic source with paraxial propagation theory. The three coupled Maxwell equations for the counterpropagating ASE waves and the transversely propagating pump wave are solved numerically in time and two spatial dimensions. This simulation is used to calculate the longitudinal profile of the transverse fluorescence, which measures the saturation of the gain, the longitudinal profile of the transmitted pump wave, which measures the saturation of pump absorption, and the transverse coherence function of the radiation emitted from the ends of the amplifier.
Getting to Know Generation X: Health Education for the Thirteenth Generation

Abstract Approximately 80 million Americans ranging in age from 11 to 31 make up the largest group of young adults in American history. This new generation has been dubbed “Generation X.” This article acquaints readers with this new generation of youth as they are described by the popular press and in health education literature. The article describes the following: (1) sociodemographic characteristics, (2) health characteristics as described in Healthy People 2000 and other health education literature, (3) learning characteristics of this generation, (4) the basis for conflict between generation X and the baby boomers, and (5) ways to conduct more effective health education with this generation given their characteristics. Recommendations for health educators, many of whom are baby boomers, to overcome these conflicts and effectively reach this group with health and education messages will be provided.
Microenvironmental Effect in Polymer-Supported Reagents. 2. The Prins Reaction and the Influence of Neighboring Group Content on Catalytic Efficiency

The microenvironmental effect on catalysis is quantified by the neighboring group content. Opposing variables in the reaction mechanism are then identified by the critical neighboring group content. The Prins reaction between formaldehyde and styrene is probed in the present study with immobilized sulfonic acid ligands as the catalyst. Cross-linked polystyrene beads were sulfonated to varying degrees of substitution. Styrene was also copolymerized with butyl methacrylate and methyl methacrylate followed by complete sulfonation of the phenyl rings. The reaction kinetics were correlated with the neighboring group content, defined as the mole percent of neighboring groups (i.e., phenyl, carbobutoxy, or carbomethoxy) relative to the total sites (neighboring and sulfonic acid) in the polymer. Increasing the phenyl group content from 0 to 25% (i.e., decreasing the degree of substitution from 100 to 75%) increases the rate constant from 23.1 to 56.2 M-1 s-1 while a further increase lowers the rate constant. The ...
The OTF In Electro-Optical Imaging Systems

The subject of image assessment and specification is of canonical importance to those involved in the research, development, and utilization of imaging systems. The quantitative assessment of something as subjective as the value of an image is essential in quantifying and communicating the needs and results of an imaging system or its components. In spite of the urgent need and the vigorous effort of the technologist responding to this need, no universally accepted standards for the measurement of image quality are available. The utilization of Fourier methods in image assessment and specification problems is currently in vogue because of their dexterity in fulfilling at least two necessary conditions as a measure of image quality. First, the Fourier methods provide a quantitative measure of image quality which reasonably correlates with the subjective effectiveness of an imaging system, and second, the analysis and performance prediction of a cascaded imaging system from a knowledge of the performance of its individual components are facilitated.© (1974) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Spectral polarity index: a new method for determining the relative polarity of solvents [1]

Abstract The relative polarity of a number of solvents, including perfluorocarbons, has been determined by measuring the bathochromic shift (as the solvent polarity increases) of the UV-visible λ max of a new class of dyes, the (α-perfluoroheptyl-β,β-dicyanovinyl)aminostyrenes [2]. This new measure of polarity, which is defined as the Spectral Polarity Index, P s , appears to be particularly useful in characterizing nonpolar solvents such as perfluorocarbons.
A review of the LU update in the simplex algorithm

In the simplex method for linear optimisation, two linear systems involving a square non-singular basis matrix B and its transpose are solved at each iteration. A column of B is then replaced, and the solution of these two linear systems is required again. For the past four decades, researchers have made considerable advancements in updating the sparse LU factors of the basis matrix in this algorithm. This paper reviews the state-of-the-art in LU update procedures, while analysing each procedure to gain a full understanding of the progress made in this area.
Up for Interpretation: How Audiences’ Unexpected Responses Threaten Social Movement Identities

Social movements challenge institutions through two related communication processes: articulating collective action frames and constructing collective movement identity. We argue that frames not only express movement identity, but also provide openings through which audiences’ interpretations and responses may shape that identity. Audiences’ unexpected responses to a movement’s frames can threaten the movement’s identity, and the salience of these threats varies based on the social movement actors’ roles. Specifically, we identify (1) a distinctiveness threat, arising from oppositional identity audiences unexpectedly embracing a movement’s framing, and most salient when movement participants act as agitators, articulating shared grievances to rally people; (2) an acceptance threat, arising from similar identity audiences when they unexpectedly reject the movement’s framing, and most salient when movement participants act as innovators, articulating possible solutions to the failings of the current state o...
Some systemic chemical responses to local inflammation.

Summary and conclusionChemical analysis of rat skin was independent of the area from which the sample was taken. Increases in hexosamine and decreases in hydroxyproline concentration found in skin necrotized with croton oil was paralleled to a lesser degree in uninjured skin. This systemic response was also found as an increase in circulating concentration of hydroxyproline in blood. Despite the statistical significance of these changes, the markedly increasing ratio of hexosamine to hydroxyproline in necrotic tissue with time was not paralleled significantly by the control.
Alcohol treatment enhances Staphylococcus aureus biofilm development.

Staphylococcus aureus forms pathogenic biofilms. Previous studies have indicated that ethanol supplementation during S. aureus biofilm formation results in increased biofilm formation and changes in gene expression. However, the impact of alcohols on preformed S. aureus biofilms has not been studied. In this study, we formed S. aureus biofilms on PVC plastic plates and then treated these preformed biofilms with five different alcohols. We observed that alcohol treatment of preformed S. aureus biofilms led to significant increases in biofilm levels after 24 h of treatment. Many bacteria within these biofilms were found to be alive and metabolically active. Alcohol treatment also resulted in increased transcription of the biofilm-promoting genes icaA and icaD, as well as several antibiotic resistance genes. These results demonstrate that treatment of S. aureus preformed biofilms with alcohols enhances biofilm levels if maintained for extended periods. Thus, alcohols might be of limited usefulness for the eradication of preformed S. aureus biofilms.
Cow power: the energy and emissions benefits of converting manure to biogas

This report consists of a top-level aggregate analysis of the total potential for converting livestock manure into a domestic renewable fuel source (biogas) that could be used to help states meet renewable portfolio standard requirements and reduce greenhouse gas (GHG) emissions. In the US, livestock agriculture produces over one billion tons of manure annually on a renewable basis. Most of this manure is disposed of in lagoons or stored outdoors to decompose. Such disposal methods emit methane and nitrous oxide, two important GHGs with 21 and 310 times the global warming potential of carbon dioxide, respectively. In total, GHG emissions from the agricultural sector in the US amounted to 536 million metric tons (MMT) of carbon dioxide equivalent, or 7% of the total US emissions in 2005. Of this agricultural contribution, 51 to 118 MMT of carbon dioxide equivalent resulted from livestock manure emissions alone, with trends showing this contribution increasing from 1990 to 2005. Thus, limiting GHG emissions from manure represents a valuable starting point for mitigating agricultural contributions to global climate change. Anaerobic digestion, a process that converts manure to methane-rich biogas, can lower GHG emissions from manure significantly. Using biogas as a substitute for other fossil fuels, such as coal for electricity generation, replaces two GHG sources—manure and coal combustion—with a less carbon-intensive source, namely biogas combustion. The biogas energy potential was calculated using values for the amount of biogas energy that can be produced per animal unit (defined as 1000 pounds of animal) per day and the number of animal units in the US. The 95 million animal units in the country could produce nearly 1 quad of renewable energy per year, amounting to approximately 1% of the US total energy consumption. Converting the biogas into electricity using standard microturbines could produce 88 ± 20 billion kWh, or 2.4 ± 0.6% of annual electricity consumption in the US. Replacing coal and manure GHG emissions with the emissions from biogas would produce a net potential GHG emissions reduction of 99 ± 59 million metric tons or 3.9 ± 2.3% of the annual GHG emissions from electricity generation in the US.
All‐Units Discounts for Standard Container Sizes

Some vendors offer their products to a purchaser in various container sizes. Normally, vendors will offer larger all-units discounts on larger container sizes. Two algorithms have been developed in this paper to solve for the optimal number of each container size and the order quantity for the deterministic economic order quantity (EOQ) situation. The first algorithm, based in part on the dynamic programming solution to knapsack problems, solves the general case. The second algorithm, based in part on the dominance relations inherent in the pricing schedule, solves the more restricted case in which the purchaser is forced to accept the discount in the following manner. An order must be filled with containers of successively smaller sizes, beginning with the largest size. The purchaser is forced to accept the largest discount first, then the next largest, and so on.
Clathrin exchange during clathrin-mediated endocytosis

During clathrin-mediated endocytosis, clathrin-coated pits invaginate to form clathrin-coated vesicles (CVs). Since clathrin-coated pits are planar structures, whereas CVs are spherical, there must be a structural rearrangement of clathrin as invagination occurs. This could occur through simple addition of clathrin triskelions to the edges of growing clathrin-coated pits with very little exchange occurring between clathrin in the pits and free clathrin in the cytosol, or it could occur through large scale exchange of free and bound clathrin. In the present study, we investigated this question by studying clathrin exchange both in vitro and in vivo. We found that in vitro clathrin in CVs and clathrin baskets do not exchange with free clathrin even in the presence of Hsc70 and ATP where partial uncoating occurs. However, surprisingly FRAP studies on clathrin-coated pits labeled with green fluorescent protein–clathrin light chains in HeLa cells show that even when endocytosis is blocked by expression of a dynamin mutant or depletion of cholesterol from the membrane, replacement of photobleached clathrin in coated pits on the membrane occurs at almost the same rate and magnitude as when endocytosis is occurring. Furthermore, very little of this replacement is due to dissolution of old pits and reformation of new ones; rather, it is caused by a rapid ATP-dependent exchange of clathrin in the pits with free clathrin in the cytosol. On the other hand, consistent with the in vitro data both potassium depletion and hypertonic sucrose, which have been reported to transform clathrin-coated pits into clathrin cages just below the surface of the plasma membrane, not only block endocytosis but also block exchange of clathrin. Taken together, these data show that ATP-dependent exchange of free and bound clathrin is a fundamental property of clathrin-coated pits, but not clathrin baskets, and may be involved in a structural rearrangement of clathrin as clathrin-coated pits invaginate.
Engineered molecular delivery for control and enhancement of transplanted endothelial cell fate in tissue engineering

A successful engineered tissue construct must acquire a functional microvascular network that rapidly connects to the host circulation. Suspended endothelial cells (EC) within a construct will spontaneously organize into a microvascular system, but maturation depends on recruitment of host mural cells and is slow and limited. We have integrated protein delivery with transplantation of EC to create multifunctional hydrogels for use in tissue engineering. These gels consist of a protein matrix that facilitates formation of nascent endothelium and alginate microparticles capable of sustained release of multiple protein therapeutics. We have shown that delivery of vascular endothelial growth factor (VEGF) accelerates the development of graft perfusion. In this study, we examine the effects of concurrent delivery of VEGF and monocyte chemoattractant protein-1 (MCP-1). We show MCP-1 release can be achieved at physiologically relevant levels for 48–72 hours, enhancing recruitment of host monocytes, a cell population that may foster angiogenesis and vascular remodeling (arteriogeneisis). Furthermore, our results indicate combining VEGF with MCP-1 delivery facilitates improved engraftment of transplanted EC in a mouse model. These data herald the utility of combined delivery of arteriogenic (MCP-1) and angiogenic (VEGF) growth factors from EC-containing hydrogels as a promising biomaterial strategy for advanced tissue engineering.
Compton Scattering in Clinical PET/CT With High Resolution Half Ring PET Insert Device

The integration of a high resolution PET insert into a conventional PET system can significantly improve the resolution and the contrast of its images within a reduced imaging field of view. For the rest of the scanner imaging field of view, the insert is a highly attenuating and scattering media. In order to use all available coincidence events (including coincidences between 2 detectors in the original scanner, namely the scanner-scanner coincidences), appropriate scatter and attenuation corrections have to be implemented. In this work, we conducted a series of Monte Carlo simulations to estimate the composition of the scattering background and the importance of the scatter correction. We implemented and tested the Single Scatter Simulation (SSS) algorithm for a hypothetical system and show good agreement between the estimated scatter using SSS and Monte Carlo simulated scatter contribution. We further applied the SSS to estimate scatter contribution from an existing prototype PET insert for a clinical PET/CT scanner. The results demonstrated the applicability of SSS to estimate the scatter contribution within a clinical PET/CT system even when there is a high resolution half ring PET insert device in its imaging field of view.