gebhart/patrepeval huggingface dataset:
Synthesis and Crystallization of Precision ADMET Polyolefins Containing Halogens (2006)

We report the synthesis and characterization of a series of precision polyethylene (PE) structures containing either a fluorine, chlorine, or bromine on each and every 19th carbon. The use of ADMET polymerization chemistry allows unprecedented control in the synthesis of these halogen containing PE derivatives, and results in the first bromine containing polyolefin with a precisely defined primary structure. Polymerization with Grubbs' first generation catalyst followed by hydrogenation by diimide reduction or Wilkinson's catalyst leads to these precise structures, which have been characterized by 1H NMR, solution and solid state 13C NMR, solid state 19F NMR, IR, elemental analysis, TGA, DSC, AFM, and WAXD. The TGA data, coupled with elemental analysis, supply definitive proof of the structural composition through the observed thermal decomposition and release of exact masses of HX (X = F, Cl, or Br). In reference to analogous random copolymers, these precisely substituted polymers display sharper WAXD diffraction patterns, higher crystallinities and much narrower melting peaks, typical of a homopolymer-like crystallization. This crystallization behavior is supported by solid-state NMR based on the observed equivalence in the relative distribution of halogens between crystalline and noncrystalline regions. Extensive experimental data provide evidence for a crystalline state built on the basis of substitutional solid solutions. Lattice distortions caused by the accommodation of the substituent in the lattice render a change from orthorhombic to triclinic structures at a van der Waals atomic radius of the solute >1.6 Å. The observed melting temperatures and enthalpies of fusion decrease dramatically with increasing volume of the substituent and scale proportionally to the van der Waals atomic radius in the halogenated series.
The effect of vitamin B<sub>12</sub> on phytoplankton growth and community structure in the Gulf of Alaska (2011)

A majority of eukaryotic phytoplankton species require an exogenous source of vitamin B 12 for growth and recent field studies in some coastal and polar regions indicate that the addition of vitamin B 12 alone, or with another limiting nutrient can influence the accumulation of phytoplankton biomass. We quantified the concentrations and uptake rates of vitamin B 12 , characterized phytoplankton community composition, and examined the ability of vitamin B 12 to alter the growth and composition of phytoplankton communities in the Gulf of Alaska. Picoplankton (0.2–2 μm) were responsible for the majority of vitamin B 12 uptake in both coastal and high‐nutrient low‐chlorophyll (HNLC) regions and B 12 concentrations and uptake rates were higher in HNLC regions compared to coastal regions with higher iron (Fe) concentrations. During vitamin amendment experiments, B 12 alone or in conjunction with other limiting nutrients (N or Fe) significantly enhanced algal biomass and increased the growth rates of multiple groups of larger (> 2 μm) phytoplankton. This included ecologically significant, B 12 auxotrophs such as Gymnodinium sp. and Alexandrium sp. (in the costal experiment) as well as Chaetoceros sp. and Gymnodinium sp. (in the HNLC experiment). The ability of vitamin B 12 to shape algal community composition in coastal and HNLC areas of the Gulf of Alaska, even in cases where it does not limit total phytoplankton production, suggests that it may influence carbon export in this and other polar ecosystems.
Treatment of Solid Malignant Tumors with Microwave Balloon Ablation Catheters and Localized Chemotherapy. (2007)

The paper describes a new approach to the treatment of solid malignant tumors. In this approach the tumors are thermally ablated with minimally invasive microwave balloon catheters, and the cavities created in the tumors by the balloon catheters are fllled with anticancer agents that can be forced through the ablated malignant tissues to the margins of the tumors in order to destroy any remaining viable tumor cells. In vivo and in vitro experiments are described that illustrate the ability of microwave balloon ablation catheters to rapidly ablate of large volumes of tissues, to create reservoirs for anticancer agents in the ablated (necrosed) tissues, and to force substances with large molecular weights that are introduced into these reservoirs through the ablated tissues to the margins of the ablation. DOI: 10.2529/PIERS060821120416
Middle Level Teacher Preparation: Principals’ Perceptions of New Teacher Preparedness--RESEARCH (2013)

Drawing on the Framework for Effective Middle Level Teaching (Faulkner, Howell, & Cook, 2012; Howell, Cook, Faulkner, 2013), this interpretive, exploratory study utilized survey methodology to analyze 38 middle level principals’ perceptions of effective teaching practices and the preparedness of newly hired middle level teachers. The findings suggest there is difference in perceptions of new teacher preparedness between principals with middle level teacher certification and principals that were prepared to teach at other grade levels. While both groups acknowledged the need for better teacher preparation, principals with middle level teacher certification reported that newly hired teachers were less prepared for effective middle level teaching. The researchers identified two primary conclusions that impact the field of middle grades teacher preparation: (a) beginning middle grades teachers need to be better prepared for effective teaching and (b) principals perceive the preparation of new teachers differently depending upon their own teaching certification, with principals holding middle grades teaching certification being more critical of the level of preparation. While both strengths and weaknesses of preparation were identified in each of the six constructs, the most relevant and important conclusion is that middle level principals perceive beginning middle grades teachers as not being adequately prepared to address the demands of effective middle grades teaching in several constructs from the Framework for Effective Middle Level Teaching.
Electrooculogram-based virtual reality game control using blink detection and gaze calibration (2016)

This paper describes an Electrooculogram (EOG) and gaze based hands-free natural interaction system design for virtual reality (VR) games which enhances the immersive VR experience. The traditional interfaces like joysticks, mouse, keyboards, hand-worn data-gloves when used with VR HMD peripherals are obtrusive for virtual experience. This is a step further towards building see-and-play user interaction in VR games. This natural interface provides an enhanced gaming experience in which the user's virtual environment is interacting as per the eye movements. Electrooculogram based online eye blink detection and gaze calibration were carried out with average efficiency of 96% and 80% respectively. Based on the calibrated eye movements, the virtual environment in the “VRrailSurfer” is adjusted and interactions with the virtual game objects are carried out. Ten subjects (8 male, 2 female) were asked to play 5 trails of our prototype VR game “VRrailSurfer”. The average real-time game control accuracy across subjects was found to be 78%. The feasibility of obtaining EOG based VR game controls and the subjective analysis of user's immersive VR experience are also discussed.
Formation of hydrated calcium silicates at elevated temperatures and pressures (1938)

An X-ray investigation of the crystalline hydrated calcium silicates which occur naturally as minerals indicated that the following are distinct compounds: . Okenite, CaO.2~iO,.2H'06 gy,rolite, 2CaO . ~S~O,.2H,O; cre~tmoreite, 2CaO.2S10,.3H,O; xonothte, 5Ca .5S10,.H,O; afwllhte, 3CaO.2S10,.3H,O; foshagite, 5CaO.3SiO,.3H,O; and hillebrandite, 2CaO.SiO . H,O. Riversideite is apparently not a distinct mineral and is probably the same compound as crestmoreite. Crystalline preparations having X-ray patterns identical with those of gyrolite, xonotlite, and foshagite were synthesized by hydrothermal treatment of calcium silicate in the form of the anhydrous crystalline compounds, glass, and amorphous hydrate. Other compounds formed were cristobalite, wollastonite, pseudowollastonite, 4CaO.5SiO,.5H,O, CaO .SiO,.H,O, 10CaO.5SiO,.6H.O, 2CaO.SiO,. H,O, and 3CaO.SiO,.2H,O. A low-temperature modification of anhydrous tricalcium disilicate, which inverts to the usual form at 1,024
Comparison of two skin imaging analysis instruments: The<scp>VISIA</scp><sup>®</sup>from Canfield vs the<scp>ANTERA</scp>3D<sup>®</sup><scp>CS</scp>from Miravex (2017)

ANTERA 3D<sup>®</sup> relies on multidirectional illumination obtained by LEDs of different wavelengths from different directions which make it advanced at the qualitative evaluation of various dermatologic conditions. Compared with VISIA<sup>®</sup> , ANTERA 3D<sup>®</sup> is more sensitive in the assessment of wrinkle and it may also be available to evaluate the aging-related enlarged pore.
Infrared spectra of the ammonium ion in crystals. Part XIV. Hydrogen bonding and orientation of the ammonium ion in fluorides, with observations on the transition temperatures in cubic cryolite, elpasolite, and perovskite halides (1985)

The ir spectra of the isotopic probe ion NH 3 D + have been used to obtain information about the symmetry, orientation, and hydrogen-bonding involvement of the ammonium ion, between 10 K and room temperature, in NH 4 F, NH 4 HF 2 , (NH 4 ) 2 [Cr(H 2 O) 6 ]F 5 , NH 4 PF 6 , (NH 4 ) 3 SiF 7 , the elpasolites (NH 4 ) 2 BFeF 6 (B = Na, K) and CS 2 NH 4 MF 6 (M = Fe, Al), and the cryolites (NH 4 ) 3 MF 6 (M = Al, Cr, Fe). Several of these fluorides exhibit low-temperature transitions, some of which are evident in the probe-ion spectra. It is shown that relating the isotopically isolated ND stretching and bending frequencies to the [Formula: see text] distances and to the coordination numbers of the ammonium ion reveals important trends in the dependence of the behaviour of the ion on its immediate environment in the crystal. A detailed discussion is presented of the effect of ionic size and the geometric tolerance factor t on the transition temperatures of cubic cryolite, perovskite, and elpasolite halides, as well as on the anisotropy of the principal thermal amplitudes of the halogen atom in such compounds. The relation between T tr and the frequency of the ND stretching absorption of NH 3 D + in the ammonium representatives of these classes of halides is also explored.
Studies on Sago Starch. Part I: Characterization and Comparison of Sago Starches Obtained from <i>Metroxylon sagu</i> Processed at Different Times (1991)

Abstract This paper reports on a study undertaken to determine some of the factors responsible for the variability shown by sago starch, which at present severely limits the commercial value of this material. Two batches of sago starch extracted from Metroxylon sagu species were characterized physicochemically and structurally. One batch was white in colour while the other was reddish‐brown. The latter contained significantly more protein (0.06%) than the former (0.015%). Non‐proteinaceous material constituted 40% of the total nitrogen in the former. The ionic contents of the two batches of starch exhibited a similar ion profile except for the following striking differences. The white batch contained 20‐fold more phosphorus and 15‐fold more aluminium whilst the reddish‐brown batch contained double the quantity of iron and calcium. The solubility and swelling capacity of both batches were also different. Amylographic representation was used to reveal the strength of starch granules during pasting. Scanning electron microscopy disclosed different degrees of pitting between the two batches, the morphology of which were also shown to be disparate. Flow curves also displayed significant differences in the rheological behaviour.
REGULATION OF SYMBIOTIC ROOT NODULE DEVELOPMENT (1998)

Symbiosis between rhizobia and leguminous plants leads to the formation of N2-fixing root nodules. The interaction of rhizobia and plants shows a high degree of host specificity based on the exchange of chemical signals between the symbiotic partners. The plant signals, flavonoids exuded by the roots, activate the expression of nodulation genes, resulting in the production of the rhizobial lipochitooligosaccharide signals (Nod factors). Nod factors act as morphogens that, under conditions of nitrogen limitation, induce cells within the root cortex to divide and to develop into nodule primordia. This review focuses on how the production of Nod factors is regulated, how these signals are perceived and transduced by the plant root, and the physiological conditions and plant factors that control the early events leading to root nodule development.
Determination of layer-specific mechanical properties of human coronary arteries with nonatherosclerotic intimal thickening and related constitutive modeling (2005)

At autopsy, 13 nonstenotic human left anterior descending coronary arteries [71.5 +/- 7.3 (mean +/- SD) yr old] were harvested, and related anamnesis was documented. Preconditioned prepared strips (n = 78) of segments from the midregion of the left anterior descending coronary artery from the individual layers in axial and circumferential directions were subjected to cyclic quasi-static uniaxial tension tests, and ultimate tensile stresses and stretches were documented. The ratio of outer diameter to total wall thickness was 0.189 +/- 0.014; ratios of adventitia, media, and intima thickness to total wall thickness were 0.4 +/- 0.03, 0.36 +/- 0.03, and 0.27 +/- 0.02, respectively; axial in situ stretch of 1.044 +/- 0.06 decreased with age. Stress-stretch responses for the individual tissues showed pronounced mechanical heterogeneity. The intima is the stiffest layer over the whole deformation domain, whereas the media in the longitudinal direction is the softest. All specimens exhibited small hysteresis and anisotropic and strong nonlinear behavior in both loading directions. The media and intima showed similar ultimate tensile stresses, which are on average three times smaller than ultimate tensile stresses in the adventitia (1,430 +/- 604 kPa circumferential and 1,300 +/- 692 kPa longitudinal). The ultimate tensile stretches are similar for all tissue layers. A recently proposed constitutive model was extended and used to represent the deformation behavior for each tissue type over the entire loading range. The study showed the need to model nonstenotic human coronary arteries with nonatherosclerotic intimal thickening as a composite structure composed of three solid mechanically relevant layers with different mechanical properties. The intima showed significant thickness, load-bearing capacity, and mechanical strength compared with the media and adventitia.
CDX2 as a marker for intestinal differentiation: Its utility and limitations (2011)

CDX2 is a nuclear homeobox transcription factor that belongs to the caudal-related family of CDX homeobox genes. The gene encoding CDX2 is a nonclustered hexapeptide located on chromosome 13q12-13. Homeobox genes play an essential role in the control of normal embryonic development. CDX2 is crucial for axial patterning of the alimentary tract during embryonic development and is involved in the processes of intestinal cell proliferation, differentiation, adhesion, and apoptosis. It is considered specific for enterocytes and has been used for the diagnosis of primary and metastatic colorectal adenocarcinoma. CDX2 expression has been reported to be organ specific and is normally expressed throughout embryonic and postnatal life within the nuclei of epithelial cells of the alimentary tract from the proximal duodenum to the distal rectum. In this review, the authors elaborate on the diagnostic utility of CDX2 in gastrointestinal tumors and other neoplasms with intestinal differentiation. Limitations with its use as the sole predictor of a gastrointestinal origin of metastatic carcinomas are also discussed.
Graft-transmissible action of Arabidopsis FLOWERING LOCUS T protein to promote flowering (2009)

Day length perceived by a leaf is a major environmental factor that controls the timing of flowering. It has been believed that a mobile, long-distance signal called florigen is produced in the leaf, and is transported to the shoot apex where it triggers floral morphogenesis. Grafting experiments have shown that florigen is transmissible from a donor plant that has been subjected to inductive day length to an un-induced recipient plant. However, the nature of florigen has long remained elusive. Recent studies have provided evidence that the FLOWERING LOCUS T (FT) protein in Arabidopsis and corresponding proteins in other species are an important part of florigen. Our work showed that the FT activity, either from overexpressing or inducible transgenes or from the endogenous gene, to promote flowering is transmissible through a graft junction, and that an FT protein with a T7 tag (FT-T7) is transported from a donor scion to the apical region of recipient stock plants and becomes detectable within a short period of 24-48 h. That the FT-green fluorescent protein (GFP) fusion protein (FT:GFP) retains limited ability for graft-transmissible action was confirmed.
Latent Olefin Metathesis Catalysts for Polymerization of DCPD (2010)

Abstract Summary: Advances in design of latent ruthenium phenylindenylidene catalysts bearing salicylaldimine ligands for ring‐opening metathesis polymerization are described. The presence of the substituents in ortho position in N‐aryl ring of salicylaldimine ligand has been found to be the main factor determining the catalyst stability. The best of the studied catalysts after acid activation offers activity comparable to that of the dichloride systems in ring‐opening metathesis polymerization of DCPD, while maintaining very high stability in the monomer solution.
Structural Analysis of<i>Cryptosporidium parvum</i> (2004)

Cryptosporidium parvum (Apicomplexa, formerly Sporozoa) is the causative agent of cryptosporidiosis, an enteric disease of substantial medical and veterinary importance. C. parvum shows a number of unique features that differ from the rest of the class of coccidea in which it is currently grouped taxonomically. Differences occur in the overall structure of the transmission form and the invasive stages of the parasite, its intracellular location, the presence of recently described additional extracellular stages, the host range and target cell tropism, the ability to autoinfection, the nonresponsiveness to anticoccidial drugs, the immune response of the host, and immunochemical and genetic characteristics. These differences have an important impact on the infectivity, the epidemiology, the therapy, and the taxonomy of the parasite. The present article describes the structural analysis of the parasite using light and electron microscopy with an emphasis on structural details unique to C. parvum.
Neopterin measured in serum and tissue culture supernates by a competitive enzyme-linked immunosorbant assay. (1989)

In this solid-phase competitive enzyme-linked immunosorbant assay for neopterin (a product of activated macrophages) in serum or supernates of cell cultures, we incubate antiserum to neopterin with standards or samples in the presence of solid-phase-bound conjugate of carrier-neopterin. Incubation with second antibody labeled with peroxidase then follows, before reaction with substrate. Analytical recovery, precision, and sensitivity of this method are similar to those of other immunoassays. The assay range is between 0.4 and 100 micrograms of neopterin per liter. Results obtained by this method compared with those from a conventional radioimmunoassay gave a correlation coefficient of 0.974.
Design Considerations for Cushion Form Bearings in Artificial Hip Joints (1991)

Lubrication mechanisms and contact mechanics have been analysed in a new generation of 'cushion form' bearings for artificial hip joints, which comprise low elastic modulus layers on the articulating surfaces. Comparisons have been made with 'hard' bearings used in existing prostheses and also with the natural hip joint. Lubricating film thicknesses are enhanced by larger contact areas and lower contact pressures. For a fixed contact area, simultaneous changes in layer thickness and radial clearance have been shown to have a small effect on elastohydrodynamic film thickness. Hard bearings designed with the same contact area as the cushion bearings produced a similar film thickness, but lubricant film thickness is not optimized in current designs. The main advantage of using a cushion bearing with low elastic modulus layers was found to be associated with microelastohydrodynamic lubrication. Careful selection of the elastic modulus is important in order to ensure that this lubrication regime was effective. Low elastic modulus layers may also produce local deformations, which enhance squeeze film action. The elastic modulus of the material should not be lower than necessary to produce effective microelastohydrodynamic lubrication, as a further reduction in modulus only increases the strain distribution in the material. A lubricant film thickness of 0.3 microns has been predicted for a cushion hip prosthesis with a femoral head diameter of 32 mm and radius of contact zone of 16 mm, using a 2 mm thick layer with an elastic modulus of 20 MPa.
How to print floating-point numbers accurately (1990)

We present algorithms for accurately converting floating-point numbers to decimal representation. The key idea is to carry along with the computation an explicit representation of the required rounding accuracy. We begin with the simpler problem of converting fixed-point fractions. A modification of the well-known algorithm for radix-conversion of fixed-point fractions by multiplication explicitly determines when to terminate the conversion process; a variable number of digits are produced. The algorithm has these properties: No information is lost; the original fraction can be recovered from the output by rounding. No “garbage digits” are produced. The output is correctly rounded. It is never necessary to propagate carries on rounding. We then derive two algorithms for free-formal output of floating-point numbers. The first simply scales the given floating-point number to an appropriate fractional range and then applies the algorithm for fractions. This is quite fast and simple to code but has inaccuracies stemming from round-off errors and oversimplification. The second algorithm guarantees mathematical accuracy by using multiple-precision integer arithmetic and handling special cases. Both algorithms produce no more digits than necessary (intuitively, the “1.3 prints as 1.2999999” problem does not occur). Finally, we modify the free-format conversion algorithm for use in fixed-format applications. Information may be lost if the fixed format provides too few digit positions, but the output is always correctly rounded. On the other hand, no “garbage digits” are ever produced, even if the fixed format specifies too many digit positions (intuitively, the “4/3 prints as 1.333333328366279602” problem does not occur).