gebhart/patrepeval huggingface dataset:
Ring-Opening Polymerization of <i>rac</i>-Lactide by Bis(phenolate)amine-Supported Samarium Borohydride Complexes: An Experimental and DFT Study (2010)

The synthesis and ring-opening polymerization (ROP) capability of bis(phenolate)amine-supported samarium borohydride and amide complexes are reported, together with a DFT study. Reaction of Na2O2NL (L = OMe, NMe2, py, or Pr) with Sm(BH4)3(THF)3 gave the borohydride complexes Sm(O2NL)(BH4)(THF) (L = OMe (2), NMe2 (3), or py (4)) or Sm(O2NPr)(BH4)(THF)2 (5). Compounds 4 and 5 lost THF in vacuo, forming phenolate O-bridged dimers 1 and 6, respectively. Reaction of H2O2NL with Sm{N(SiHMe2)2}3(THF)2 formed monomeric Sm(O2NL){N(SiHMe2)2}(THF) (L = OMe (7), NMe2 (8), or py (9)) with tetradentate O2NL ligands, but dimeric Sm2(μ-O2NPr)2(O2NPr)(THF) (10) with tridentate O2NPr. Reaction of Sm{N(SiMe3)2}3 with H2O2NL (L = OMe or NMe2) led to zwitterionic products Sm(O2NL)(HO2NL). The bulkier amide compounds Sm(O2NL){N(SiMe3)2}(OEt2)n (n = 1, L = OMe (12) or py (13); n = 0, L = NMe2 (14)) were prepared by reaction of Sm(O2NL)(BH4)(THF) with KN(SiMe3)2. The X-ray structures of 2, 5, 6, 7, 10, 13, and 14 were determined. The borohydrides 2−5 were very efficient initiators for the ROP of ε-CL, giving linear dihydroxytelechelic poly(ε-CL). Selected amide initiators were also assessed but gave poorer control, as judged by broad PDI (Mw/Mn) values and significant amounts of cyclic poly(ε-CL)s. Of the borohydrides, only 2−4 were active for the ROP of rac-LA, and activity increased in the order O2NL = O2NOMe ≈ O2Npy < O2NNMe2. The latter ligand also gave the best control of the ROP, as judged by the PDIs and Mn values. All gave heterotactically enriched poly(rac-LA) with Pr values in the range 0.82−0.84. The ROP of rac-LA with the amides 7, 9, and 12 was faster but much less well controlled. Overall, the borohydride initiators were superior for the ROP of both ε-CL and rac-LA when compared to otherwise identical amide initiators. MALDI-ToF MS analysis of the poly(rac-LA) formed with 3 showed both −CH(Me)CHO and −CH(Me)CH2OH end groups originating from the insertion of the first LA monomer into the Sm−BH4 moiety of 3. In contrast, 2 and 4 formed only α,ω-dihydroxy-terminated polyesters with −CH(Me)CH2OH and −CH(Me)OH end groups. DFT calculations on Eu(O2′NNMe2)(BH4) found two mechanisms for the initial ring-opening step of LA by the borohydride group, giving pathways leading to either aldehyde- or alcohol-terminated poly(lactide)s. Of these two pathways, the one giving α,ω-dihydroxy-terminated polymers was the most favored, in agreement with experiment. (Ligand abbreviations: O2NL = RCH2N(CH2-2-O-3,5-C6H2tBu2)2 where R = CH2OMe, CH2NMe2, py, or Et for L = OMe, NMe2, py, or Pr, respectively; O2′NNMe2 = Me2NCH2CH2N(CH2-2-O-C6H4)2.)
Real-time monitoring of immunochemical interactions with a tantalum capacitance flow-through cell (1992)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReal-time monitoring of immunochemical interactions with a tantalum capacitance flow-through cellAndreas. Gebbert, Manuel. Alvarez-Icaza, Walter. Stoecklein, and Rolf D. SchmidCite this: Anal. Chem. 1992, 64, 9, 997–1003Publication Date (Print):May 1, 1992Publication History Published online1 May 2002Published inissue 1 May 1992https://pubs.acs.org/doi/10.1021/ac00033a007https://doi.org/10.1021/ac00033a007research-articleACS PublicationsRequest reuse permissionsArticle Views428Altmetric-Citations117LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Wide Field of View CCD Camera Based on Multi-sensors Image Mosaics (2008)

It is difficult to acquire the whole scene at the same time, when the size of a requiring scene is beyond the scope of a CCD camera. In this case, the requiring scene can be captured by several CCD cameras at one time, and the overlapped images can be acquired. Using the images, the whole scene is reproduced. This paper presents an approach of using multi-sensor and image mosaics technique to implement a wide field of view CCD camera. Based on theoretic argumentation, the robust image mosaics method, and the hardware platform designing are given in detail. The results of experiment have proved the effectiveness and feasibility of this approach.
The microRNA-200 Family Regulates Epithelial to Mesenchymal Transition (2008)

Epithelial-mesenchymal transition (EMT) is implicated in metastasis initiation and has recently been shown to be regulated by the miRNA-200 family and miR-205. Expression of these miRNAs was lost in invasive breast cancer cell lines displaying mesenchymal-like morphology suggesting these microRNAs may play a role in cancer metastasis.
Effects of exposure to tobacco smoke in pregnancies complicated by oligohydramnios and premature rupture of the membranes. I. Concentration of Cd and Pb in blood and Zn, Cu, Cd and Pb in amniotic fluid. (2000)

To assess the exposure to tobacco smoke in pregnant women with oligohydramnios, idiopathic or caused by premature rupture of the membranes (PROM), cotinine concentrations were measured, using enzyme-like immunosorbent assay (ELISA). In women with idiopathic oligohydramnios (22-31 weeks of gestation), serum cotinine concentration was 1010 +/- 445 micrograms/L which provides evidence that women of this group were heavy smokers. In these women, significantly higher Cd concentrations in blood and amniotic fluid were found as compared to other pregnant women. A positive correlation between Cd concentrations in blood and amniotic fluid was observed (PROM r = 0.784; p < 0.001; idiopathic oligohydramnios r = 0.7118; p < 0.02). In oligohydramnios cases of both types, Cd concentration in amniotic fluid was over two times and Pb concentration ten times lower than blood concentrations of these metals, whereas amniotic fluid Zn concentration was two times lower than that found earlier in women with normal pregnancy. In the group of women with idiopathic oligohydramnios who were mostly exposed to tobacco smoke, a considerably larger number of still births and new-borns with CNS disorders than in PROM cases, were observed. Zn deficiency at increased exposure to Cd and Pb could play a significant role in etiology of these abnormalities. A positive correlation was found between Zn and Cu concentrations (r = 0.862; p < 0.05) in PROM cases which indicates regular transport of trace metals to the fetal ovum. The condition of infants born to this group of women was much better, and prematurity was the only complication of pregnancy.
Mechanisms of stretch‐induced muscle damage in normal and dystrophic muscle: role of ionic changes (2005)

Muscle damage, characterized by prolonged weakness and delayed onset of stiffness and soreness, is common following contractions in which the muscles are stretched. Stretch-induced damage of this sort is more pronounced in the muscular dystrophies and the profound muscle damage observed in these conditions may involve similar pathways. It has been known for many years that damaged muscles accumulate calcium and that elevating calcium in normal muscles simulates many aspects of muscle damage. The changes in intracellular calcium, sodium and pH following stretched contractions are reviewed and the various pathways which have been proposed to allow ion entry are discussed. One possibility is that TRPC1 (transient receptor potential, canonical), a protein which seems to form both a stretch-activated channel and a store-operated channel, is the main source of Ca(2+) entry. The mechanisms by which the changes in intracellular ions contribute to reduced force production, to increased protein breakdown and to increased membrane permeability are considered. A hypothetical scheme for muscle damage which incorporates these ideas is presented.
The Tissue-Engineered Auricle: Past, Present, and Future (2011)

The reconstruction, repair, and regeneration of the external auricular framework continue to be one of the greatest challenges in the field of tissue engineering. To replace like with like, we should emulate the native structure and composition of auricular cartilage by combining a suitable chondrogenic cell source with an appropriate scaffold under optimal in vitro and in vivo conditions. Due to the fact that a suitable and reliable substitute for auricular cartilage has yet to be engineered, hand-carved autologous costal cartilage grafts and ear-shaped porous polyethylene implants are the current treatment modalities for auricular reconstruction. However, over the last decade, significant advances have been made in the field of regenerative medicine and tissue engineering. A variety of scaffolds and innovative approaches have been investigated as alternatives to using autologous carved costal cartilage or porous polyethylene implants. A review of recent developments and the current state of the art and science is presented, focusing on scaffolds, cell sources, seeding densities, and mechanical characteristics of tissue-engineered auricular cartilage.
A new method to analyze multiexponential transients for deep-level transient spectroscopy (1990)

A new technique is introduced to analyze digitally recorded capacitive transients in order to determine the properties of deep states. Using a nonlinear double exponential fitting routine, it is shown that a two-trap model can be applied to the transient data. We determine the individual trap concentrations and produce two Arrhenius plots. The latter yields the thermal activation energies and capture cross sections of closely spaced traps. The excellent agreement between the new technique and the standard rate window technique is shown via a simulation deep-level transient spectroscopy spectrum. The new method is applied to Se-doped AlxGa1−xAs (x=0.19 and 0.27) grown by metal-organic chemical vapor deposition. The measured results for all deep states including the DX centers agree well with the values published in the literature.
Diminished priming of neonatal polymorphonuclear leukocytes by lipopolysaccharide is associated with reduced CD14 expression (1995)

Previous research in our laboratory has shown that polymorphonuclear leukocytes (PMN) from neonates are not primed effectively in vitro with lipopolysaccharide (LPS) (from Escherichia coli 0111:B4) compared with priming of adult PMN. This finding led us to speculate that differences between neonatal and adult LPS receptors may account for the lower response by neonatal PMN to LPS. In these experiments, we investigated if CD14 or other LPS receptors contribute to the priming activity of PMN by LPS. We found that unprimed neonatal and adult PMN expressed similar numbers of CD14 (11.6 +/- 9.2 versus 18.6 +/- 2.7 fluorescence units [FlU]; P > 0.05) and LPS-binding sites (2.94 +/- 1.4 versus 4.94 +/- 0.79 FlU; P > 0.05). Monoclonal antibody against CD14 (MY4) did not significantly change the binding of LPS to adult unprimed PMN, suggesting that LPS receptors other than CD14 receptors are predominant on PMN. However, when PMN were pretreated with LPS (10 ng/ml) for 45 min at 37 degrees C, expression of CD14 on adult PMN increased to 33.8 +/- 4.9 FlU (P < 0.05 versus unprimed adult PMN) while that on neonatal PMN showed little change, increasing to 17.2 +/- 10.3 FlU (P > 0.05 versus unprimed neonatal PMN; P < 0.05 versus primed adult PMN). Furthermore, MY4 specifically blocked oxidative-radical production from PMN primed with LPS (10 ng/ml) compared with that from control PMN (P < 0.01). These studies suggest that LPS primes PMN by activating CD14 expression. We conclude that lower expression of CD14 or failure to up-regulate CD14 after LPS pretreatment contributes to the inability of neonatal PMN to be primed by LPS.
The Multi-Circuit System Electric Discharge Machining Process (1970)

Recently, the most important task in electric discharge machining is to increase of the working speed.The multi-circuit system electric discharge machining is a method of using a number of discharge circuits and corresponding number of electrodes to the circuit in order to get the working speed.But it is very difficult to control an autmatic feeding device and work of the single through hole.In this case. these electrodes are insulated electrically from each other and they are mechanically combined into one body so as to be fed by an automatic feeding device.Then it was revealed that the circuit number effciency is η=0.8 by experimental result.From this study, expect that the most effectual application of the multi-circuit system is discharge grinding machine
Botulinum Toxin Complex: A Delivery Vehicle of Botulinum Neurotoxin Traveling Digestive Tract (2012)

© 2012 Watanabe et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Botulinum Toxin Complex: A Delivery Vehicle of Botulinum Neurotoxin Traveling Digestive Tract
Oxygen−Carbon Bond Dissociation Enthalpies of Benzyl Phenyl Ethers and Anisoles. An Example of Temperature Dependent Substituent Effects<sup>1</sup> (2001)

For some time it has been assumed that the direction and magnitude of the effects of Y-substituents on the Z-X bond dissociation enthalpies (BDE's) in compounds of the general formula 4-YC(6)H(4)Z-X could be correlated with the polarity of the Z-X bond undergoing homolysis. Recently we have shown by DFT calculations on 4-YC(6)H(4)CH(2)-X (X = H, F, Cl, Br) that the effects of Y on CH(2)-X BDE's are small and roughly equal for each X, despite large changes in C-X bond polarity. We then proposed that when Y have significant effects on Z-X BDE's it is due to their stabilization or destabilization of the radical. This proposal has been examined by studying 4-YC(6)H(4)O-X BDE's for X = H, CH(3), and CH(2)C(6)H(5) both by theory and experiment. The magnitudes of the effects of Y on O-X BDE's were quantified by Hammett type plots of DeltaBDE's vs sigma(+) (Y). Calculations reveal that changes in O-X BDE's induced by changing Y are large and essentially identical (rho(+) = 6.7-6.9 kcal mol(-)(1)) for these three classes of compounds. The calculated rho(+) values are close to those obtained experimentally for X = H at ca. 300 K and for X = CH(2)C(6)H(5) at ca. 550 K. However, early literature reports of the effects of Y on O-X BDE's for X = CH(3) with measurements made at ca. 1000 K gave rho(+) approximately 3 kcal mol(-)(1). We have confirmed some of these earlier, high-temperature O-CH(3) BDE's and propose that at 1000 K, conjugating groups such as -OCH(3) are essentially free rotors, and no longer lie mainly in the plane of the aromatic ring. As a consequence, the 298 K DFT-calculated DeltaBDE for 4-OCH(3)-anisole of -6.1 kcal mol(-)(1) decreases to -3.8 kcal mol(-)(1) for free rotation, in agreement with the ca. 1000 K experimental value. In contrast, high-temperature O-CH(3) DeltaBDE's for three anisoles with strongly hindered substituent rotation are essentially identical to those that would be observed at ambient temperatures. We conclude that substituent effects measured at elevated temperatures may differ substantially from those appropriate for 298 K.
A novel implementation for narrow-band FIR digital filters (1975)

In an earlier paper Crochiere and Rabiner [1] discuss the theory of using finite impulse response (FIR) digital filters for signal decimation, interpolation, and filtering. In this paper we expand on the ideas presented in the earlier paper on implementing narrow-band designs efficiently. It is shown how, using the techniques of decimation and interpolation, a desired narrow-band filter can be realized with a greatly reduced number of multiplications per second in the realization over standard direct form implementations. Further, it is shown that the proposed implementation can have less roundoff noise and less severe coefficient sensitivity problems than a standard direct form implementation. Several examples are presented to illustrate the applicability of this implementation to practical design problems.
Attentional control of early perceptual learning. (1993)

The performance of adult humans in simple visual tasks improves dramatically with practice. This improvement is highly specific to basic attributes of the trained stimulus, suggesting that the underlying changes occur at low-level processing stages in the brain, where different orientations and spatial frequencies are handled by separate channels. We asked whether these practice effects are determined solely by activity in stimulus-driven mechanisms or whether high-level attentional mechanisms, which are linked to the perceptual task, might control the learning process. We found that practicing one task did not improve performance in an alternative task, even though both tasks used exactly the same visual stimuli but depended on different stimulus attributes (either orientation of local elements or global shape). Moreover, even when the experiment was designed so that the same responses were associated with the same stimuli (although subjects were instructed to attend to the attribute underlying one task), learning did not transfer from one task to the other. These results suggest that specific high-level attentional mechanisms, controlling changes at early visual processing levels, are essential in perceptual learning.
Analysis of nonselective plasma etching of AlGaN by CF4∕Ar∕Cl2 (2005)

We report the nonselective plasma etching of epitaxial GaN:Mg, Al0.63Ga0.37N, and AlN∕Al0.08Ga0.92N short-period superlattices with various doping properties. Etching is performed using mixed CF4∕Ar feed gases in a combined inductively coupled plasma and reactive-ion etching chamber. A uniform etch rate of ∼23nm∕min is obtained for each of the compositions studied under identical conditions. This nonselective etching is also found to preserve the surface uniformity studied by atomic force microscopy and quantified using surface roughness and lateral correlation length. By adding Cl2 gas, etch rates are increased to 230–250nm∕min without degrading the surface properties.
The MORGAN framework (2004)

The availability of a suitable framework is of vital importance for the development of Augmented Reality (AR) and Virtual Reality (VR) projects. While features such as scalability, platform independence, support of multiple users, distribution of components, and an efficient and sophisticated rendering are the key requirements of current and future applications, existing frameworks often address these issues only partially. In our paper we present MORGAN --- an extensible component-based AR/VR framework, enabling sophisticated dynamic multi-user AR and VR projects. Core components include the MORGAN API, providing developers access to various input devices, including common tracking devices, as well as a modular render engine concept, allowing us to provide native support for individual scene graph concepts. The MORGAN framework has already been successfully deployed in several national and international research and development projects.
Cock Spermatozoa Serve as the Gene Vector for Generation of Transgenic Chicken (Gallus gallus) (2004)

To evaluate the feasibility of using sperm-mediated gene transfer (SMGT) for carrying foreign gene into chicken oocyte, a reporter gene, CX-EGFP, was used in this study. The reporter gene was first mixed with liposome or liposome-like compound and the mixtures were further combined with ejaculated cock spermatozoa. The spermatozoa treated with liposome and CX-EGFP mixture was subsequently coincubated with DNaseI to remove the extra DNA which insured the authenticity of positive signals. The treated sperms were then subjected to transgene (reporter gene) existence analysis and artificial insemination of laying hens. Obtained results indicated that the spermatozoa were able to take-in the foreign DNA; which was confirmed by polymerase chain reaction and Southern blot analysis. In the following experiment, fresh ejaculated sperms were mixed with CX-EGFP-liposome or CX-EGFPliposome-like complex then used for artificial insemination of each of six laying hens. Eggs laid between day-3 and day-7 post insemination were collected. Newly hatched chicks, two out of 53 from CX-EGFP/liposome treated group and two out of 21 from CX-EGFP/liposome-like treated group, were proven to be transgenic. This study suggests that SMGT is a powerful method for generating transgenic chickens. (
The effect of megestrol acetate on anorexia, weight loss and cachexia in cancer and AIDS patients (review). (1997)

Weight gain is a well-known side-effect of megestrol acetate (MA) treatment. This effect has been studied systematically in cancer and AIDS patients with involuntary weight loss, anorexia or manifest cachexia, situations in which weight gain is desirable. Significant, positive effects on weight gain and on certain quality of life aspects, such as appetite, nausea, body image and mood have been reported for cancer patients treated with 160 mg to 1.600 mg daily and similar effects have been registered in AIDS patients if doses of about 400-800 mg are used. Maximal weight gain is normally achieved within 8 weeks. The weight gain is, unfortunately, mainly due to an increase in fat mass and partly due to edema and, therefore, no significant effects are reported as regards the Karnovsky index. If anorexia, nausea and a negative body image are major concerns and if the patient has a life expectancy of more than 3 months, MA is a reasonable treatment option. However, if the central problem is fatigue and a low Karnovsky index, especially in a patient with a short expected survival, MA, which is not inexpensive, is not likely to be of significant help.