cssi/SciSciGPT-SciSciNet huggingface dataset:
The Polymerase Chain Reaction

It is difficult to underestimate the impact of the polymerase chain reaction (PCR) and related DNA amplification techniques on modern molecular biology and applied molecular medicine. PCR represents a rapid, sensitive, and specific method for amplification of nucleic acid sequences and is the basis for numerous molecular techniques that have become the mainstay of the basic research laboratory, as well as the clinical diagnostics laboratory. The concept of PCR was first described in 1985 (1), and the modern technique emerged a few years later (2). Since that time, the technology has evolved into a reliable and affordable method that is performed in laboratories worldwide. When reduced to its essence, PCR is a molecular technology that facilitates the amplification of rare copies of specific nucleic acid sequences to produce a quantity of amplified product that can be analyzed. In early descriptions of PCR (1,3,4), the Klenow fragment of Escherichia coli DNA polymerase I was used for DNA synthesis during each amplification cycle. However, Klenow fragment is not thermal-stable. Therefore, after each denaturation step the samples were quickly cooled before the addition of enzyme to avoid heat denaturation of the polymerase enzyme and it was necessary to add a fresh aliquot of Klenow fragment enzyme after each denaturation cycle. In addition, the primer hybridization and DNA synthesis steps were carried out at 30°C to preserve the activity of the poly-merase enzyme, resulting in hybridization of primers to nontarget sequences and considerable nonspecific amplification (4). Even with these drawbacks, the original PCR methodology was successfully applied to gene cloning and molecular diagnostic experiments (1,3,4). The major technological breakthrough in development of PCR came with the introduction of a thermostable polymerase to PCR (2). Thermus aquaticus is a bacterium that lives in hot springs and is adapted to the variations in ambient temperature that accompany its environment. The DNA polymerase enzyme expressed by T. aquaticus (known as Taq polymerase) exhibits robust polymerase activity that is relatively unaffected by rapid fluctuations in temperature over a wide range (5). Introduction of Taq to PCR improved the practicality of this methodology. Because Taq polymerase can survive extended incubation at the elevated temperatures required for DNA denaturation (93–95°C), there is no need to add a new enzyme after each cycle. In addition, by using a heat block that automatically changes temperatures (a thermocy-cler), the PCR cycles becomes automated. Incredibly, the basic PCR technique has not changed that much since 1988 (2), although new developments in commercially available molecular reagents have made the technique easier to perform.
Amphoteric behavior of bovine plasma albumin and its detergent complexes.

Abstract Hydrogen ion titration curves have been determined for two stoichiometric albumin-detergent complexes, AD11 and AD76, which are formed through interaction between bovine plasma albumin and the detergent sodium dodecyl benzenesulfonate. The amphoteric properties of the protein moiety in these two complexes have been compared with one another and with those of the uncombined protein. In this analysis, electrophoretic mobility data were used for making the necessary corrections for electrostatic interaction. Tyrosyl ionization curves were established for all three forms by measuring the change with pH of absorption at 295 mµ. The most significant differences found are in the tyrosyl ionization. For albumin itself, the apparent value of pKint is approximately 11.0, and it is concluded that some masked tyrosyl residues are exposed in a cooperative structural change accompanying the ionization. In the case of AD11, tyrosyl ionization is distinctly hypersharp and the apparent pKint is 11.3, implying that in this form the protein is stabilized against unmasking of the tyrosyl residues. In AD76 the apparent pKint is again near 11.0. The titration behavior of imidazole groups is virtually identical in the native protein and in the AD11 complex. In both cases it is necessary to assume two classes of imidazole groups in order to fit the titration curve. In AD76 the titration of these groups can be fitted adequately with a single pKint of 7.30. Surprisingly, very little difference is seen between the various forms in the titration of the e-amino groups. This fact permits the conclusion that electrostatic interaction between the detergent anions and cationic ammonium groups cannot contribute more than 700 cal to the free energy of binding, whereas the total binding free energy (on the unitary scale) must be of the order of 10,000 cal. The fact that the stoichiometry of the complexes is virtually unaltered over the pH range 6.9 to 11.6, over which range the total number of cationic sites in the protein falls from approximately 100 to 40, supports the conclusion that binding is not primarily electrostatic but is probably due to hydrophobic interactions. To a first approximation, all results suggest that the protein in AD11 is essentially in the native state and in fact is stabilized with respect to the structural alteration which must occur on conversion to AD76.
Radioimmunoassay for Bacteroides fragilis infections

Radioimmunoassay methods were evaluated for immunoglobulin G and immunoglobulin M antibodies against Bacteroides fragilis antigen. Of 12 serum samples from patients with B fragilis infections, 9 had higher concentrations of immunoglobulin G antibodies than any from 11 control subjects. Of 9 serum samples from infected patients, 6 had higher concentrations of immunoglobulin M than any from control subjects. Six serum samples from patients with Escherichia coli bacteremia did not contain elevated concentrations of immunoglobulin G or immunoglobulin M antibodies against B. fragilis antigen.
Heat and mass transfer in porous media phase separation at temperatures below the lambda-point of He-4

Newtonian fluid motion, coupled to heat transfer via latent heat of phase transition, is well known from numerous studies of condensation and boiling. Considerably less knowledge is available for vapor-liquid phase separation in the absence of gravity effect on the transport phenomena. The present studies are focused on heat and mass transfer associated with vapor-liquid phase separation required for long-term storage of the cryogen liquid He II in space vessels. Though space conditions are the dominant mode of interest in advanced equipment, e.g. IR telescopes, the systems may be operated in principle during terrestrial conditions. The latter are considered in the present work. It emphasizes the linear regime including an extrapolation based on variable thermophysical properties. Data taken with a phase separation approach show departures from the linear regime prediction. They agree with a transport equation proposed for the nonlinear, turbulent regime.
The role of suppressive language policies in language shift and language loss

The Skutnabb-Kangas and Phillipson analysis of linguistic human rights is used as a basis for understanding language replacement phenomena in the United States. Use of Spanish in Chicano communities is shifting rapidly to English despite the huge numbers of recent immigrants who are dominant in Spanish. Accompanying this shift is a precipitous loss of proficiency by Spanish speakers. Such replacement of a language does not depend on personal choices made by speakers, but on the socio-political conditions within the country. Political goals of profits, exploitation, and hegemony drive classist, racist and ethnicist policies whose purpose is to neutralize resistance to the status quo. These are couched in liberal-sounding myths that justify linguicism, which strives to suppress minority cultures and to acculturate their members in order to pacify perceived ethnic group conflict. The Skutnabb-Kangas and Phillipson Linguicism Continuumn is used to demonstrate the degree of linguistic repression in selected U.S. institutions.
Post-Crisis Compensation at Credit Suisse (A)

On October 20, 2009 Brady Dougan, the CEO of Credit Suisse Group, announced a new compensation plan for the bank. The announcement had followed quickly on the heels of the G-20 meeting the prior month where, in the wake of the financial crisis, the major governments had laid out a set of guidelines for compensation in the financial industry. Credit Suisse Group was the first firm to adopt the G-20 guidelines, and did so a year ahead of the suggested timetable. While responsive to the concerns of regulators and politicians, Credit Suisse's program was more than a knee-jerk reaction, the new compensation plan had been the result of a "10 year journey" to reshape the culture of the firm. After a significant investment of senior leadership time to explain the new program to employees a significant new challenge arose. On December 9, the U.K. government announced they would impose a one-time 50% tax on bankers' bonuses greater than 25,000 pounds. Dougan and the executive team had to decide how best to fund this tax. Was it fair or appropriate to have the shareholders shoulder the burden of the tax? Similarly, was it fair to ask the UK employees to suffer relative to their peers in other countries?
Differences in Competence and Beliefs About Autism Among Teacher Education Students

Students with autism often are placed in general education classrooms, indicating general education teachers should be prepared to meet these students' needs. This survey study of teacher education students examined differences in educational training, beliefs about autism, and competence working with students with autism, according to college level and major area of study. Results showed that teacher education students held accurate beliefs about most aspects of autism, but they demonstrated misconceptions about special, gifted abilities. Secondary teacher education students were less likely to demonstrate accurate beliefs about the social emotional features of autism over the course of their training. General education teachers reported a lack of competence working with students with autism and believed additional training was needed. Findings suggested ongoing preservice training is needed to foster accurate beliefs about autism and competence working with students with autism.
Cutting Edge: Antigen-Specific Thymocyte Feedback Regulates Homeostatic Thymic Conventional Dendritic Cell Maturation

Thymic dendritic cells (DC) mediate self-tolerance by presenting self-peptides to and depleting autoreactive thymocytes. Despite a significant role in negative selection, the events regulating thymic DC maturation and function under steady-state conditions are poorly understood. We report that cross-talk with thymocytes regulates thymic conventional DC (cDC) numbers, phenotype, and function. In mice lacking TCR-expressing thymocytes, thymic cDC were reduced and exhibited a less mature phenotype. Furthermore, thymic cDC in TCR-transgenic mice lacking cognate Ag expression in the thymus were also immature; notably, however, thymic cDC maturation was re-established by an Ag-specific cognate interaction with CD4 + or CD8 + single-positive thymocytes (SP). Blockade of CD40L during Ag-specific interactions with CD4 SP, but not CD8 SP, limited the effect on cDC maturation. Together, these novel findings demonstrate that homeostatic maturation and function of thymic cDC are regulated by feedback delivered by CD4 SP and CD8 SP via distinct mechanisms during a cognate Ag–specific interaction.
Immune-mediated and unusual complications during interferon alfa therapy in chronic myelogenous leukemia.

PURPOSELong-term treatment with interferon alfa (IFN alpha) can produce or exacerbate immune-mediated complications (IMC). The purpose of this study was to analyze the experience with IMC and unusual complications in patients with chronic myelogenous leukemia (CML) undergoing IFN alpha treatment.PATIENTS AND METHODSThe occurrence of IMC and unusual complications was evaluated in patients with Philadelphia chromosome (Ph)-positive CML.RESULTSWell-documented and clinically evident complications developed in 35 patients after a median of 14 months of IFN alpha treatment. These included 28 (5%) of 581 patients with Ph-positive CML treated with IFN alpha-containing regimens at M.D. Anderson Cancer Center (MDACC) and seven patients referred for opinion or problems who were on other studies. Hypothyroidism occurred in 11 patients (2%), immune-mediated hemolysis in seven (1%), and connective tissue diseases in 11 (2%). Other unusual occurrences included congestive heart failure (CHF; n = 4), porphyria cutanea tar...
Rating the major computing periodicals on readability

The readability of the ten major computing periodicals is analyzed using the Flesch Reading Ease Index.
Dynamical analysis of a RHEED pattern from the Si(111)-7 × 7 surface

Abstract The multislice formalism of Cowley and Moodie [Acta Crystallogr. 10 (1957) 609] with a recently developed edge-patching method has been applied to the analysis of an experimental RHEED (reflection high energy electron diffraction) pattern from the Si(111)-7 × 7 surface. Several data sets of atomic coordinates for the Si(111)-7 × 7 reconstruction, optimized by different approaches, have been evaluated based upon comparison of visually estimated intensity ordering between the observed and calculated patterns. The results show that compared to other data sets, the coordinates optimized by ab initio-parallel computation appear closer to the true structure, so far as the RHEED in the current scheme can judge. The analysis also shows that the intensities of a RHEED pattern taken from the surface are highly surface sensitive. The surface sensitivity extends to the whole selvage region of interest with a depth of ∼10 A. The correlation between mean inner potential V 0 and the angle of incidence θ has also been investigated. This indicates that if the angle of incidence is measured with errors less than ± 0.05° for this specific case, V 0 can be determined with the accuracy of ∼± 10%, and vice versa.
A model with Heterogeneous Half-Sarcomeres Exhibits Residual Force Enhancement After Active Stretch

A skeletal muscle fiber that is activated and then stretched from L1 to L2 produces more force after the transient decays than if it was activated at L2. This behavior has been well studied experimentally, and is known as residual force enhancement. The underlying mechanism remains controversial. We hypothesized that residual force enhancement could reflect mechanical interactions between heterogeneous half-sarcomeres.To test this hypothesis, we subjected a computational model of interacting heterogeneous half-sarcomeres [Campbell KS, PLoS Comput Biol 2009:5(11)] to the same activation and stretch protocols that produce residual force enhancement in real preparations. Following a transient period of elevated force associated with active stretching, the model predicted a slowly decaying force enhancement lasting >30 seconds after stretch. Enhancement was on the order of 10% above isometric tension at the post-stretch muscle length, which agrees closely with experiments under similar conditions. Force enhancement in the model was proportional to stretch magnitude but did not depend strongly on the velocity of stretch, also in agreement with experiments. Small but noticeable enhancement could be seen at muscle lengths on the ascending limb of the static length-tension curve, and increased with length up to an average half-sarcomere length of ∼1400 nm. Even small variability in the strength of half-sarcomeres (5% standard deviation, normally distributed) was sufficient to produce a 5.7% force enhancement over isometric tension. Model analysis suggests that heterogeneity in half-sarcomeres leads to residual force enhancement by storing strain energy introduced during active stretch in crossbridge populations and in passive structures within and between half-sarcomeres. Complex interactions between the heterogeneous half-sarcomeres then dissipate stored energy at a rate much slower than that of crossbridge cycling, thereby producing force enhancement.
The free food (contrafreeloading) phenomenon: A review and analysis

Animals will perform an operant response to obtain food when abundant free food is available. These data have implications for current learning theories, especially in terms of the motivational variables associated with such behavior. The present paper reviews the literature and provides an analysis that suggests that responding for food in the presence of free food is importantly controlled by stimulus change attendant upon response-dependent food presentation. This apparent stimulus-reinforcer effect on behavior is compared to that observed in other areas of animal learning research that include preference between schedules of response-dependent and response-independent reinforcement, preference between schedules of signaled and unsignaled reinforcement, autoshaping and automaintenance, and self-reinforcement in animals.
Accurate ball detection in soccer images using probabilistic analysis of salient regions

Automatic sport video analysis has became one of the most attractive research fields in the areas of computer vision and multimedia technologies. In particular, there has been a boom in soccer video analysis research. This paper presents a new multi-step algorithm to automatically detect the soccer ball in image sequences acquired from static cameras. In each image, candidate ball regions are selected by analyzing edge circularity and then ball patterns are extracted representing locally affine invariant regions around distinctive points which have been highlighted automatically. The effectiveness of the proposed methodologies is demonstrated through a huge number of experiments using real balls under challenging conditions, as well as a favorable comparison with some of the leading approaches from the literature.
The Influence of Mechanical Environment on Bone Healing and Distraction Osteogenesis

Review of bone mechanics To begin to understand the effects of mechanical forces on bone, such as those that occur during distraction osteogenesis (DO), it is necessary to consider the makeup of the bone and the features that enable it to respond to mechanical loading. Bone is a dynamic organ and, as such, it is in a constant state of change as affected by factors including nutrition, disease, and mechanical environment. Whether these changes alter the quantity or quality of the bone depends upon considerations such as their severity and duration. For practical purposes, bone can be considered a composite material. That is, in addition to water, bone is comprised of organic materials and inorganic matrix. While the organic material, such as collagen, gives bone its resilience and tensile strength, the mineralized matrix gives bone its compressive strength. The mineralized matrix also serves as the structural housing for the osteocytes. The osteocytes are the most abundant bone cells in the body and before becoming encased in their own matrix were bone-forming osteoblasts. These osteocytes reside in lenticular cavities called lacunae. In turn, the lacunae are connected to each other by way of a network of interconnecting channels called canaliculi. While the osteocyte bodies reside in the lacunae, their long, slender processes reside in the canaliculi. Interstitial fluid bathes the lacuno-canalicular network providing for nutrient exchange. This network may also play an important role in transducing mechanical signals. The osteocytes are able to physically link with each other through this porous environment and, many believe, amplify the mechanosensory response at the cellular level such that, among other functions, minimal loading can maintain bone integrity. These bone cells not only link and form networks with each other, but they also maintain contact with the surface-residing osteoblasts. It is hypothesized that the osteocytes act as strain gauges sensing mechanical deformation and communicate this signal to bone-forming osteoblasts that coordinate their activity with boneresorbing osteoclasts, possibly by way of soluble signaling (Fig. 1). Two important bone types emerge, distinguishable largely by the level of porosity. Cortical (or compact) bone, comprising the hollow shafts of long bones and the thin cortices surrounding trabecular bone, typically has a porosity on the order of 5% to 10%; whereas cancellous (or spongy or trabecular) bone forming the bodies of flat and cuboidal bones typically has a porosity on the order of 75% to 95%. With the interstitial fluid running throughout these porous bone networks, bone is characterized not only by its porous mineral matrix, but also its fluid constituents, giving rise to the distinction that bone is also referred to as a poroelastic material. When a bone is under mechanical load, its performance is governed by its size, shape, and the material that comprises it. Collectively, these features determine the mechanical properties
When numbers matter most.

We each leave our daughters, ages two and seven years. March 4, their shared birthday. Improving health communication with the dying, our shared goal. We travel for work, to conferences and researc...
A Numerical Calculation of the Circulation in the North Atlantic Ocean

Abstract A series of numerical experiments are carried out to simulate the three-dimensional circulation in the North Atlantic Ocean and to examine the dynamics therein. The calculations are partly diagnostic in that the density field is not predicted but is given from observations. The main predicted quantities are the velocity and pressure fields. The results of the basic experiment are compared with observations. The surface currents are quite similar to observations based upon ship drift data, and the surface pressure field is nearly identical to the height of the free surface constructed from a level-of-no-motion hypothesis. The deep pressure variations are nowhere flat or level, however, and the predicted deep currents are quite complex. They are, in fact, strongly controlled by bottom topography and tend to follow f/H contours, where f is the Coriolis parameter and H the depth. The Gulf Stream transport is quite large, reaching a maximum value of 81×106 m3 sec−1, despite the lack of important inert...
Mason: A Global Floorplanning Approach for VLSI Design

A global floorplanning approach is presented which allows designers to quickly explore layout issues during the initial stages of the IC design process. The approach is based on a combined mincut and slicing paradigm, in an effort to ensure routability. A slicing-tree representation is employed, upon which efficient traversal operations are applied resulting in area-efficient floorplans. The method allows modules to be specified as having a number of possible dimensions, and considers I/O pads as well as layout constraints. As a global improvement over previous floorplanning efforts, an in-place partitioning scheme is applied in conjunction with a combined exhaustive and heuristic bipartitioning approach. Moreover, a global channel routing and module I/O pin assignment scheme is used for floorplan evaluation, whereby module dimensions are chosen in conjunction with routing area, ensuring compact floorplans. A computer program, Mason, is presented which efficiently implements the approach and provides an interactive environment for designers to perform floorplanning. The performance of the program is discussed in terms of several industrial examples.
Conductivity, Viscosity, and Dissolution Enthalpy of LiNTF2 in Ionic Liquid BMINTF2

The ionic conductivity, relative viscosity, and solution enthalpy of LiNTF2 and NaNTF2 solutions in ionic liquid BMINTF2 have been measured. We observed that the conductivity decreased and the viscosity increased when the Li+ and Na+ salts were dissolved in BMINTF2. We also observed that the dissolution is an exothermic process with a solution enthalpy of approximately −18.07 ± 4.61 kJ/mol. The experimental results indicate that the Li+ ion may associate with multiple NTF2− anions in the BMINTF2 solution to form a solvated complex.
Development, trafficking, and function of memory T‐cell subsets

The precise mechanisms that govern memory T-cell lineage commitment during an immune response continue to be the subject of intense scrutiny. The existence of memory T-cell subsets defined by location, function, and phenotype adds an additional layer of complexity to the overall memory T-cell population. In this review, the integration of memory subset development and migration and the functional consequences of specific tissue localization are discussed.
Lumpy preference structures

A widely held and durable normative position has been that policy analysts should attempt to estimate the evaluative reaction of those who will be most directly affected by a government sponsored or regulated technology. The premise of applied welfare economics is that citizens would divide, substitute and additively recombine their assessments of the project's impacts in the same manner. This paper outlines an alternative theory by arguing that citizen preferences will often be contingent upon, rather than divisible from, the substantive and procedural characteristics of the context in which a choice takes place. Moreover, one can predict that the manner in which these evaluations are substituted and recombined will vary with the internal structure of one's value and belief system. By representing that system in terms of a hierarchical model composed of four factors — common orientation, procedural judgment, desire for personal control and substantive evaluation — it is argued that the evaluations of a project will be combined by way of interactive, indirect and non-recursive relationships as well as the common additive expectations. Some of the implications of this alternative theory for policy analysis are explored.
Development of ultra-small-angle X-ray scattering–X-ray photon correlation spectroscopy

This paper describes the development of ultra-small-angle X-ray scattering–X-ray photon correlation spectroscopy (USAXS–XPCS). This technique takes advantage of Bonse–Hart crystal optics and is capable of probing the long-time-scale equilibrium and non-equilibrium dynamics of optically opaque materials with prominent features in a scattering vector range between those of dynamic light scattering and conventional XPCS. Instrumental parameters for optimal coherent-scattering operation are described. Two examples are offered to illustrate the applicability and capability of USAXS–XPCS. The first example concerns the equilibrium dynamics of colloidal dispersions of polystyrene microspheres in glycerol at 10, 15 and 20% volume concentrations. The temporal intensity autocorrelation analysis shows that the relaxation time of the microspheres decays monotonically as the scattering vector increases. The second example concerns the non-equilibrium dynamics of a polymer nanocomposite, for which it is demonstrated that USAXS–XPCS can reveal incipient dynamical changes not observable by other techniques.
Changing appearance of retinal arteriovenous malformation

Retinal arteriovenous malformations (racemose angiomas) are usually described as non-changing congenital vascular anomalies. The authors describe prominent retinal vascular changes that occurred in the fundus of a patient with a complex retinal arteriovenous malformation as part of the Wyburn-Mason syndrome during a follow-up period of 17 years.
Formation of a Trypsin−Borate−4-Aminobutanol Ternary Complex

The formation of ternary complexes involving serine proteases, borate, and an alcohol has important implications for understanding the physiological actions of borate and for the development of tight binding inhibitors for this class of enzymes. Recent studies of a related enzyme, gamma-glutamyl transpeptidase, which is subject to inhibition by a labile serine/borate mixture, have demonstrated that construction of a non-labile boronate analogue results in an inhibitor with nearly 10(5)-fold greater potency. To evaluate the generalization of this biochemistry to serine proteases, we have observed the ternary complex formed from 4-aminobutanol, borate, and trypsin. A combination of (11)B and (1)H NMR and spectrophotometric assays using acetylarginine p-nitroanilide (Ac-Arg-pNA) as the chromogenic substrate all indicate a cooperative binding interaction in which the borate is esterified by the oxygen atoms of the 4-aminobutanol and trypsin residue Ser(195). Two downfield-shifted proton resonances at 15.5 and 16.6 ppm are proposed to arise from the labile imidazolium protons on His(57), indicating a salt bridge interaction with the negatively charged borate. A cooperativity parameter alpha of 0.2 is derived from the assays. These results provide the first direct evidence for formation of a ternary complex involving a serine protease, borate, and an alcohol, and suggest that this represents a general approach for the development of tight binding ligands.
Recent Development of Silica Nanoparticles as Delivery Vectors for Cancer Imaging and Therapy

In spite of significant advances in early detection and combined treatments, a number of cancers are often diagnosed at advanced stages and thereby carry a poor prognosis. Developing novel prognostic biomarkers and targeted therapies may offer alternatives for cancer diagnosis and treatment. Recent rapid development of nanomaterials, such as silica based nanoparticles (SiNPs), can just render such a promise. In this article, we attempt to summarize the recent progress of SiNPs in tumor research as a novel delivery vector. SiNP-assisted imaging techniques are used in cancer diagnosis both in vitro and in vivo. Meanwhile, SiNP-mediated drug delivery can efficiently treat tumor by carrying chemotherapeutic agents, photosensitizers, photothermal agents, siRNA, and gene therapeutic agents. Finally, SiNPs that contain at least two different functional agents may be more powerful for both tumor imaging and therapy.
Natural convection in a thin horizontal porous annulus

Abstract The possible modes of time-dependent natural convection in a horizontal annulus of finite length are considered. The annulus is filled with porous material and the annular thickness is assumed small in comparison with the mean radius. All boundaries are impermeable and adiabatic; heating is through a circumferentially distributed volumetric heat source. The governing equations reduce to a set of two non-linear ordinary differential equations. Steady non-linear oscillations exist for the special case of infinite Rayleigh number and symmetric heating about the vertical. For lower Rayleigh numbers, damped oscillations are obtained, the degree of damping increasing with the inclination of the line of symmetry and with decreasing Rayleigh number. Multiple stable steady states are obtained for small inclinations. Chaotic motions do not develop for non-inertial Darcy flows.
Benzo[1,2-b:4,5-b′]dithiophene Building Block for the Synthesis of Semiconducting Polymers

This review covers the synthesis and polymerization of benzo[1,2-b: 4,5-b']dithiophene (BDT) to generate semiconducting polymers used in organic field-effect transistors (OFET) and organic solar cells applications.
ω-Haloalkyl esters of 5′-adenosine monophosphate as potential active-site-directed reagents for dehydrogenases

Abstract A series of esters of adenosine 5′-monophosphate with ethyl, propyl, or hexyl moieties substituted at the ω-position with chlorine or bromine were prepared. The compounds were competitive inhibitors of horse liver alcohol dehydrogenase with respect to coenzyme, NAD + , and had inhibition (dissociation) constants in the range of 40 to 260 μ m at pH 8.0, 25 °C. The bromoalkyl esters were designed to be active-site-directed inactivators and were chemically reactive as tested with the model compound 4-( p -nitrobenzyl)pyridine. Yeast alcohol dehydrogenase was inactivated by the bromohexyl analog by an active-site-directed mechanism, with a K i = 1.5 mM and a pseudo-bimolecular rate constant of 0.03 m −1 s −1 , which is 150 times larger than the bimolecular rate constant for inactivation by 2-bromoethanol. However, the rates of inactivation of other dehydrogenases treated with 10 m m concentrations of these compounds were generally slower than with the simpler reagent, 2-bromoethanol. Thus, the reactive functional group attached to the AMP moiety may not be properly oriented for affinity labeling of these dehydrogenases. The bromoalkyl esters may be useful for inactivating other enzymes.
Determination of cyanuric acid or trichloroisocyanuric acid in air

Abstract An analytical procedure for measurement of cyanuric acid or trichlor oisocyanuric acid in air has been developed. The procedure involves air sampling with a 37-mm PVC membrane filter, recovery with a phosphate buffer, and analysis by high performance liquid chromatography with a UV detector at 225 nm. The interior surface of the front piece of the cassette filter holder also is analyzed. Average recoveries were 0.98 to 1.00 after fortification of PVC filters with 12- to 412-μg quantities of cyanuric acid. Average recoveries of trichloroisocyanuric acid were 0.83 to 0.98 after fortification of glass surfaces with 12- to 424-μg quantities (these are reasonable approximations for recoveries of trichloroisocyanuric acid from PVC filters). The analyst should ascertain which analyte is present at the sampling site because trichloroisocyanuric acid reacts with water in the phosphate buffer to form cyanuric acid in high yield.
RALPH application for surface mount assembly

Automated assembly in the electronics industry offers many advantages over traditional assembly methods. As product lives become shorter and batch numbers become smaller, new programming methods will be needed to shorten the lead time for these automated lines. Providing a method for humans to interact with the robot in a natural language mode will lead to some of these advantages. Task-level programming deals with the interactions of objects rather than robot motions and therefore requires little robotic expertise but allows for easy and fast programming. One of the long-term projects aimed at alleviating the above problem is the development of a Robotic Assembly Language Planning Hierarchy (RALPH), a task-level automatic robot programming language with natural language commands. In surface mount assembly, the PC board must be populated with chips with high tolerances—a few thousandths of an inch. The part features are so small that human assemblers constantly make mistakes. The redeeming aspect of the components with regard to assembly lies in the geometry of the features. In this article we capitalize on the above geometric attributes of chips and chip pads on PCBs in order to apply the principles of RALPH in the development of a system for automatic assembly.
Oxide formation on rare earth/transition metal and bimetallic transition metal thin films: modeling the effect of fourth element modifiers on O2 and H2O surface chemistries

Abstract The chemical reactions undergone by both O 2 and H 2 O on (a) rare earth (Tb), (b) rare-earth transition metal alloy (FeTbCo), (c) transition metal (Fe and Ti), and (d) transition metals, modified with thin overlayers of another metal (Fe/Ti), have been studied by surface photoelectron spectroscopies, starting with the clean metals in UHV environment. Various degrees of reactivity are indicated, especially for adsorption and dissociation of H 2 O, depending upon whether the pure metals are studied, or mixtures of metals, which change the type and extent of dissociation of H 2 O (oxide vs. hydroxide formation).
Density fluctuations in the interstellar medium: Evidence for anisotropic magnetogasdynamic turbulence. II - Stationary structures

A model of anisotropic, plasma-fluid variations was used to investigate the unknown origin of the power spectra of interstellar electron fluctuations inferred by Armstrong, Cordes, and Rickett (1981). The modeled electron variations are interpreted as density components of an anisotropic stationary mode of nonlinear magnetogasdynamics-tangential pressure balances. It is suggested that the wavenumber spectra of electron variations are identical to the spectra of the convecting velocity fields over a wide range of wavenumbers.
Real-time position monitoring of invasive devices using magnetic resonance†

Techniques which can be used to follow the position of invasive devices in real-time using magnetic resonance (MR) are described. Tracking of an invasive device is made possible by incorporating one or more small RF coils into the device. These coils detect MR signals from only those spins near the coil. Pulse sequences which employ nonselective RF pulses to excite all nuclear spins within the field-of-view are used. Readout magnetic field gradient pulses, typically applied along one of the primary axes of the imaging system, are then used to frequency encode the position of the receive coil(s). Data are Fourier transformed and one or more peaks located to determine the position of each receiver coil in the direction of the applied field gradient. Subsequent data collected on orthogonal axes permits the localization of the receiver coil in three dimensions. The process can be repeated rapidly and the position of each coil can be displayed in real-time.
Language samples using three story elicitation tasks and maturation effects

The spoken language skills of 20 elementary students with verified learning disabilities were explored using a story format and discourse analysis procedure. The purpose was to compare the performance of LD students on three types of story tasks (story generation from a picture, story generation from memory, and story generation based on a game) over a one-year period. Results indicated statistically significant main effects for approximately half (9/17) of the discourse variables by task and one main effect for time. Overall, stories from memory were longer and characterized by more as well as different types of errors than were stories from pictures or stories based on games. Implications for use of stories and type of story collection task in language sampling are discussed.
Hot alkali carbonation of sodium metaphosphate modified fly ash/calcium aluminate blend hydrothermal cements

Sodium metaphosphate-modified fly ash/calcium aluminate blend (SFCB) cements were prepared by autoclaving for 1 day at 300 C and their resistance was evaluated in a highly concentrated Na{sub 2}CO{sub 3} solution at 300 C. The hydroxyapatite and analcime phases formed in the autoclaved SFCB cements played an essential role in conferring resistance to the degradation of cements caused by alkali carbonation. Although the carbonating reaction of the analcime phase led to the formation of cancrinite, this analcime cancrinite transformation did not show any influence on the changes in the mechanical and physical properties of the cements. Additionally, there was no formation of the water-soluble calcium bicarbonate in the cements exposed for 28 days. Contrarily, the conventional class G cement systems were very vulnerable to a hot alkali carbonation. The major reason for the damage caused by carbonation of the cements was the fact that the xonotlite phase formed in the 300{degree} autoclaved cements was converted into two carbonation products, calcite and pectolite. Furthermore, the reaction between calcite and carbonic acid derived from Na{sub 2}CO{sub 3} led to the formation of water-soluble calcium bicarbonate, thereby causing the alteration of dense structures into porous ones and the loss of strength of cements.
Effective optical constants of anisotropic materials.

The applicability of a technique for determining the optical constants of soil or aerosol components on the basis of measurements of the reflectance or transmittance of inhomogeneous samples of component material is investigated. Optical constants for a sample of very pure quartzite were obtained by a specular reflection technique and line parameters were calculated by classical dispersion theory. Predictions of the reflectance of powdered quartz were then derived from optical constants measured for the anisotropic quartz and for pure quartz crystals, and compared with experimental measurements. The calculated spectra are found to resemble each other moderately well in shape, however the reflectance level calculated from the psuedo-optical constants (quartzite) is consistently below that calculated from quartz values. The spectrum calculated from the quartz optical constants is also shown to represent the experimental nonrestrahlen features more accurately. It is thus concluded that although optical constants derived from inhomogeneous materials may represent the spectral features of a powdered sample qualitatively a quantitative fit to observed data is not likely.
Slag cement utilization: Rheological properties and related characterization

Abstract Mortars prepared from slag-cement blends have been shown to exceed or equal the strengths of portland cement mortars at 7 to 28 days. Such cements have further potential advantages in their performance with regard to durability, and in their early stage properties which govern workability. The early stage rheological properties including mortar flow, yield stress, and viscosity were investigated, combined with zeta potential measurements, and used to explain the excellent workability. The working time of slag cement may be extended to later ages compared with portland cements through use of superplasticizers.
Comparisons of Daily Sea Surface Temperature Analyses for 2007–08

Abstract Six different SST analyses are compared with each other and with buoy data for the period 2007–08. All analyses used different combinations of satellite data [for example, infrared Advanced Very High Resolution Radiometer (AVHRR) and microwave Advanced Microwave Scanning Radiometer (AMSR) instruments] with different algorithms, spatial resolution, etc. The analyses considered are the National Climatic Data Center (NCDC) AVHRR-only and AMSR+AVHRR, the Navy Coupled Ocean Data Assimilation (NCODA), the Remote Sensing Systems (RSS), the Real-Time Global High-Resolution (RTG-HR), and the Operational SST and Sea Ice Analysis (OSTIA); the spatial grid sizes were , respectively. In addition, all analyses except RSS used in situ data. Most analysis procedures and weighting functions differed. Thus, differences among analyses could be large in high-gradient and data-sparse regions. An example off the coast of South Carolina showed winter SST differences that exceeded 5°C. To help quantify SST analysis diff...
Ultrafast Laser-Induced Elastodynamics in Single Crystalline Silicon Part II: Near-Field Response

The multi-time scale ultrafast laser model of axisymmetric geometry presented in Part I is validated with computed carrier densities and melting thresholds that agree well with published physical data. Transport phenomena initiated by femtoseconds heating including the spatial and temporal evolutions of electron and lattice temperatures and electron-hole carrier density are highly localized in both time and space. The temporal and spatial scales associated with the generation of thermal stress waves are significantly larger at tenths of nanoseconds and microns, respectively. Ultrashort laser pulse induced transverse stress waves are highly dispersive and characteristically of broadband, low amplitude, and extremely high frequency and power density contents. Near-field responses that precede the development of a full-blown plate wave are also localized in space with a power density magnitude on the order of 1013 Watts per cubic meters in volume.
Population Dynamics of Bemisia argentifolii (Homoptera: Aleyrodidae) on Spring Collard and Relationship to Yield in the Lower Rio Grande Valley of Texas

Abstract Seasonal population dynamics of the silverleaf whitefly, Bemisia argentifolii Bellows & Perring [formerly known as the sweetpotato whitefly, B. tabaci (Gennadius) Biotype “B”], was investigated on collard (Brassica oleracea L. variety acephala) during spring 1998 and 1999 in the Lower Rio Grande Valley of Texas. Yield loss caused by whitefly was determined by using insecticides to suppress whitefly populations to a low level. Although B. argentifolii populations of adults and immatures fluctuated greatly from April to June during the two seasons, the relative values were similar. Adult whiteflies first appeared on the plants in early April, increased rapidly within the month, peaked in May, and declined at the end of the season in early or mid-June. Whitefly eggs appeared on plants soon after adults were found, but high numbers of eggs were observed on foliage until late May 1998 and mid- and late May 1999. Nymphs and pupae increased slowly before June 1998 and increased early in May 1999. Whitef...
Piecewise-linear-basis-function expansions

A new method of representing a signal using piecewise-linear basis functions has been described. The letter provides a very simple method of determining the expansion coefficients as linear combinations of samples of the signal.
Lipid metabolism of Periplaneta americana L. during embryogenesis

Abstract 1. 1. During development the weight of oothecae of the American cockroach decreased by 25 per cent, 17 per cent being due to water loss, the remainder largely to lipid catabolism. 2. 2. The major lipid fractions were separated by silicic acid column chromatography and their constituents identified and quantitated by thin layer chromatography. 3. 3. Total extractable lipid decreased from 39·5 to 23·2 per cent of the dry weight of the oothecae. Of the major lipid classes, only the triglyceride fraction decreased, this by 75 per cent. 4. 4. Mono- and diglycerides remained constant until the time of nymphal emergence when they increased sharply, indicating intense triglyceride hydrolysis.
Inheritance, Mode of Inheritance, and Candidate Genes for Primary Hyperparathyroidism in Keeshonden

Background: Primary hyperparathyroidism (PHPT) is caused by inappropriate secretion of parathyroid hormone (PTH) by autonomously functioning neoplastic or hyperplastic parathyroid “chief cells. Keeshonden are thought to be over-represented in studies on canine PHPT, but no proof of heritability or mode of inheritance has been published. The canine disease clinically resembles human familial isolated hyperparathyroidism (FIHP). Hypothesis: Primary hyperparathyroidism in Keeshonden is genetically transmitted and is caused by a mutation in 1 of 4 genes implicated in human FIHP: MEN1, CASR, HRPT2, or RET. Animals: Pedigrees consisting of 1647 Keeshonden were created including 219 Keeshonden with known PHPT phenotypes (69 positive). DNA samples were obtained from 176 of the 219 Keeshonden (34 positive). Methods: Heritability and mode of inheritance were determined by segregation analysis. Canine homologs to the human genes were identified. Exons and surrounding intron regions were sequenced and scanned for sense-altering polymorphisms or polymorphisms that segregated with the disease. Messenger RNA from a parathyroid tumor of an affected Keeshond was analyzed for polymorphisms and splice alterations. Results: PHPT follows an autosomal dominant mode of inheritance in Keeshonden with possible age-dependent penetrance. No polymorphisms identified in the genes analyzed were associated with a change in predicted protein or in hypothesized splice sites. Conclusions and Clinical Importance: PHPT is an autosomal dominant, genetically transmitted disease in Keeshonden. Once the mutation locus is identified, genetic testing should quickly decrease the incidence of PHPT in this breed. It is unlikely that mutations in MEN1, CASR, HRPT2, or RET cause PHPT in Keeshonden.
The role of random blackout cues in the distribution of moments of stuttering.

Johnson and Millsapps have shown that when stuttered words are blotted out in successive readings of a passage there is a tendency for residual stutterings to occur on adjacent words. They interpre...