Microcomputer learning in small groups: Cognitive requirements and group processes.

35 self-selected 11–14 yr olds learned LOGO for 1 wk in 3-person groups that were homogeneous with respect to previous experience with computers. A battery of cognitive pretests yielded different profiles that were used to predict different programming outcomes. Ss were posttested for achievement. Results show that mathematics ability was the best predictor of knowledge of syntax, interpreting graphics programs, and generating relations programs. Spatial ability was the best predictor of knowledge of basic commands. A combination of spatial ability and field independence best predicted generating graphics programs. Of 11 group process variables examined, 5 predicted programming outcomes: receiving explanations in response to errors (positively related), receiving explanations in response to questions (negatively related), not receiving explanations after an error (negatively related), receiving no response to a question (negatively related), and time at the keyboard (positively related). No student demographic characteristic or ability was related to the 5 group process variables. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

应用废铬钴催化剂为原料生产陶瓷、玻璃色料的研究探讨

对氟化工艺废铬钴催化剂回收利用进行了研究,分析了废铬钴催化剂的主要成分.探讨了利用废铬钴催化剂开发陶瓷、玻璃高温色料的方法.通过一系列的试验,得到了陶瓷、玻璃高温黑色色料,此色料加入坯料中打板烧成,发色稳定,着色力强.     

NAcSDKP analogues resistant to angiotensin-converting enzyme

Two series of analogues of the tetrapeptide NAcSDKP, an inhibitor of hematopoietic stem cell proliferation, were prepared, and their enzymatic stability toward rabbit lung angiotensin-converting enzyme (ACE) was evaluated as well as their capacity to inhibit NAcSDKP hydrolysis by this enzyme. In the first series, each of the peptide bonds has been successively replaced by an aminomethylene bond. In the second one, the C-terminus of the peptide has been modified by decarboxylation or amidation. The results reported here indicate that all of these molecules but one have good stability toward the enzyme but none of the compounds is able to inhibit NAcSDKP hydrolysis by ACE.     

Viscosupplementation with hylan G-F 20: a 26-week controlled trial of efficacy and safety in the osteoarthritic knee

Cortical color blindness, or cerebral achromatopsia, has been likened by some authors to "blindsight" for color or an instance of "covert" processing of color. Recently, it has been shown that, although such patients are unable to identify or discriminate hue differences, they nevertheless show a striking ability to process wavelength differences, which can result in preserved sensitivity to chromatic contrast and motion in equiluminant displays. Moreover, visually evoked cortical potentials can still be elicited in response to chromatic stimuli. We suggest that these demonstrations reveal intact residual processes rather than the operation of covert processes, where proficient performance is accompanied by a denial of phenomenal awareness. We sought evidence for such covert processes by conducting appropriate tests on achromatopsic subject M.S. An "indirect" test entailing measurement of reaction times for letter identification failed to reveal covert color processes. In contrast, in a forced choice oddity task for color, M.S. was unable to verbally indicate the position of the different color, but was surprisingly adept at making an appropriate eye movement to its location. This "direct" test thus revealed the possible covert use of chromatic differences.     

Chiral surfactants in micellar electrokinetic capillary chromatography

Most biologically active molecules contain one or more chiral centres, giving rise to stereoisomeric forms which can behave differently in a chiral environment. Thus, only one of the enantiomers may show the desired physiological activity, whereas the other enantiomers may either be considerably less active or even show undesireable side effects. Establishing that a chiral drug consists of one single enantiomer is nowadays essential before it can be given to patients. Analytical tools that can discriminate between enantiomers play a very important role in determining the stereoisomeric composition of chiral molecules. Until recently chromatographic techniques were the most popular for enantiomeric separations. The increased use of capillary electrophoresis (CE) has provided complementary methodology for chiral discrimination. One mode of CE that has been used for this purpose is micellar electrokinetic capillary chromatography (MECC), where natural or synthetic chiral surfactants are added to the separation buffer.     

Rare earth double activated phosphors for different applications

For the purpose of development of highly energy-efficient light sources,one needs to design highly efficient green,red and yellow phosphors,which are able to absorb excitation energy and generate emissions.In this contribution,we present our results on producing some efficient phosphors with improved luminescence properties.Using double activation,energy could be transferred from one luminescent activator to the other one,resulting in more efficient or brighter device operation.Co-activators could be added to a host material to change the color of the emitted light.The incorporation of Eu3+ or Tb3+ ions into the CaWO4 crystal lattice modified the luminescence spectrum due to the formation of the emission centers that generated the specific red and green light.Very efficient new red phosphors based on YNbO4 and doped by Eu3+,Ga3+,Al3+ allowed recommending these materials as good candidates for different applications including LED and X-ray intensifying screens.For double activated TAG with Ce3+ and Eu3+ and for different mole ratios of Ce/Eu,the color temperature changed from 5500 K(0.331,0.322) up to 4200 K(0.370,0.381) and the light became "warmer".Application of TAG:Ce,Eu in the light emitting device showed better chromaticity coordinates of luminescence and color rendering index of LEDs.     

Use of photo-anchoring of DNA probes for fluorescent in situ hybridization

A possibility was investigated to use photo-crosslinking DNA probes for fluorescent in situ hybridization (FISH). DNA probes were modified by incorporating photonucleotides in these, containing a photoreactive group (tetrafluorobenzazid) and capable of making covalent bonds with the examined DNA, when irradiated in 300-330 nm region. The photonucleotide was incorporated into the probe either by nick-translation, or upon elongation of the hybridized probe by the Kljonow fragment. It has been shown that the DNA probe, cross-linking to a chromosome as a result of covalent bonds, is not removed from the place of hybridization under consequent denaturating washing, which makes it possible to carry out the following DNA hybridization with selective conservation of signals obtained due to previous hybridization. This peculiarity of photo-linking DNA probes makes it possible to use them for the two-step DNA hybridization. To demonstrate this, preparations of human chromosomes were investigated. On the first step, chromosomal DNA was hybridized by means of DNA probe having nucleotide sequences of centromeric regions of chromosomes 13 and 21, the probe being linked to chromosomal DNA by the photonucleotide. Following the denaturation treatment of the preparation, and after the second chromosomal DNA hybridization with cosmid DNA, containing chromosome 13 DNA nucleotide sequence, the signal in chromosome 13 centromeric region was retained to serve a marker of this chromosome, thus fascilitating its easier identification following the hybridization of its DNA with cosmic DNA. The denaturation stability of photo-crosslinking probes opens some new possibilities in technology of DNA in situ hybridization.     

Childhood leukaemia: towards an integrated psychosocial intervention programme in Singapore

Presumably ribosome and transfer RNA (tRNA) evolved from a pre-existing function in the RNA stage of life and were secondarily adapted for protein synthesis. Various possible initial functions of the primitive ribosome (protoribosome) have been suggested. The initial function of the primitive ribosome and primitive genetic translation would have been quite similar. It is possible that, initially, both functions coexisted in the protoribosome. Given that the three-dimensional structure of ribosomal RNAs shows only minor variations throughout time, it is, then, most likely that present ribosomes can still recall (remember) the most important parts of the mechanism of their initial function. A process would have arisen to inactivate the initial function of the protoribosome without affecting genetic translation: the modification of some ribosome nucleosides. We suggest that the modifications of some rRNA nucleosides located in the catalytic center responsible for the initial function of primitive ribosomes, and of some of the tRNA nucleosides which interacted with the same center could have resulted in the inability of their recognition and secondary interaction. Thus, it is a known fact that the establishing of hydrogen bonds between modified nucleosides is rare and unstable. Therefore, the initial biological function of primitive ribosomes could have been inactivated without significantly affecting its three-dimensional structure. Therefore, without affecting the primitive translation. After the emergence of translation, some catalytic proteins (enzymes) which could modify the nucleosides of ribozymes could have arisen. In brief, we suggest that the catalytic proteins, through nucleoside modification, inactivated the catalytic RNA activity but RNA capacity to recognize and to bind other RNAs was not essentially altered. Only a few ribozymes were slightly affected by the modifications and they still maintain catalytic and binding activities. Therefore, we suggest that the proteins, through modification process, could have diminished the diverse functional capacities of the first RNA molecules. Auto-organization of the organic matter could be based on this type of interaction between macromolecules (protein and RNA).     

Direct mass spectrometric analysis of ozonides: application to unsaturated glycerophosphocholine lipids

The reaction of ozone with double bonds present in glycerophosphocholine lipids results in formation of ozonides that can be directly analyzed by mass spectrometry as either positive or negative molecular ion species generated by electrospray ionization. Polyunsaturated fatty acyl groups esterified to the phospholipid yielded a mixture of ozonide species with the maximum number of ozone molecules added equal to the total number of double bonds. Ozonide decomposition resulted in omega-aldehyde and omega-carboxylic acid products as revealed by ESI-MS. Collisional activation of the ozone adducts for mono- and polyunsaturated phospholipids gave rise to fragment ions indicative of the position of the double bonds in these molecules. The major decomposition pathway for either positive or negative ozonide ion species involved charge remote fragmentation of the ozonide initiated by homolytic cleavage of the peroxide bridge followed by rearrangement to form the omega-aldehyde and omega-carboxylate acyl species. The reaction of ozone with phospholipids containing polyunsaturated fatty acyl groups is a useful method to probe the position of double bonds by electrospray ionization mass spectrometry.     

The Effect of Human Command Phonetic Characteristics on Auditory Cognition in Dogs (Canis familiaris).

Six dogs (Canis familiaris) were trained to sit and come reliably in response to tape-recorded commands. The phonemes within these commands were then changed, and the dogs' behavior in response to these modified commands was recorded. Performance markedly declined in all cases, with the type of alteration affecting response to the modified sit command but not to the modified come command. The results suggest that dogs do not perceive a tape-recorded command as simply a physical sound but that they recognize a relationship between certain sounds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

建筑铝合金表面处理技术的现状与发展

阐述了目前建筑铝合金表面处理技术的研究和应用现状,指出它们都有相似的前处理过程,阳极氧化电解着色法成本低,技术成熟,染色法颜色丰富,电泳涂漆和静电喷涂有着良好的耐候性,电镀更具金属光泽,最后对未来的发展提出了几点展望。     

Form of fluorine in Na2O-NaF-SiO2 slags determined by infrared spectroscopy

Abstract

The form of fluorine in Na₂O-NaF-SiO₂ slags has been investigated using Fourier transform infrared spectroscopy. Additions of NaF shifted absorption peaks for stretching modes of Si O bonds to higher wavenumbers, where the basicity of (mol-%Na₂O)/ (mol-%SiO₂ ) was kept constant, and the shift became larger with an increase in the concentration of NaF. This shift can be explained by the change from Si-O to Si-F bonds, with reference to harmonic oscillation theory of diatomic molecules. It is likely that added NaF depolymerises the silicate network to form Si-F bonds in Na₂O-NaF-SiO₂ slags.     

Rare earth double activated phosphors for different applications

For the purpose of development of highly energy-efficient light sources, one needs to design highly efficient green, red and yellow phosphors, which are able to absorb excitation energy and generate emissions. In this contribution, we present our results on producing some efficient phosphors with improved luminescence properties. Using double activation, energy could be transferred from one luminescent activator to the other one, resulting in more efficient or brighter device operation. Co-activators could be added to a host material to change the color of the emitted light. The incorporation of Eu³⁺ or Tb³⁺ ions into the CaWO₄ crystal lattice modified the luminescence spectrum due to the formation of the emission centers that generated the specific red and green light. Very efficient new red phosphors based on YNbO₄ and doped by Eu³⁺, Ga³⁺, Al³⁺ allowed recommending these materials as good candidates for different applications including LED and X-ray intensifying screens. For double activated TAG with Ce³⁺ and Eu³⁺ and for different mole ratios of Ce/Eu, the color temperature changed from 5500 K (0.331, 0.322) up to 4200 K (0.370, 0.381) and the light became “warmer”. Application of TAG: Ce, Eu in the light emitting device showed better chromaticity coordinates of luminescence and color rendering index of LEDs.     

Apoptosis dependent decrease of the intramembrane ion traffic in cultured mouse fibroblasts shown by conductivity dispersion

A new approach to the molecular modelling of homologous serine proteases is adopted, by including a set of 21 buried waters known to be preserved in enzymes sharing the primary specificity of trypsin, in the homology modelling of rat submaxillary gland kallikrein. Buried waters--water molecules sequestered from bulk solvent within a protein matrix--appear to be integral conserved components of all serine proteases of known structure and should be incorporated into serine protease models built on the basis of sequence/structural homology to this family. The absence of such waters might induce errors in a force field simulation, favouring the formation of nonexistent hydrogen bonds and locally inaccurate structure. The kallikrein model refinement has led to the conclusion that an additional buried water should be added to the original rigid matrix of 21 conserved water molecules. The structurally preserved protein cavities of such waters validate the modelled structure.     

Recent developments in osmotic agents for peritoneal dialysis

Although glucose is still the most widely used osmotic agent for peritoneal dialysis, it has several disadvantages that challenge its long-term use. During the past years several nonglucose molecules have been tested as osmotic agents for peritoneal dialysis. Most of these molecules have some advantages over glucose, but they also have drawbacks. Every new agent should be carefully tested for performance and long-term safety. In the following review, alternative osmotic agents are discussed, including their potential indications and drawbacks. Major issues include the improvement of biocompatibility and preservation of peritoneal membrane integrity by using dialysate with more physiologic pH, the effect on nutritional status by using dialysate with amino acids, and maintenance of peritoneal ultrafiltration in the long-term by using dialysate with polyglucose. It is believed that in the near future, mixtures of osmotic agents will become most appropriate to obtain the best performance.     

Ribozymes: structure, function, and potential therapy for dominant genetic disorders

Some dominant genetic disorders, viral processes and neoplastic disorders base their pathogenicity on the production of protein or proteins that negatively affect cellular metabolism or environment. Thus, the inhibition of the synthesis of those proteins should prevent the biological damage. A promising approach to decreasing the level of the abnormal protein(s) is represented by specific interference with gene expression at the level of mRNA. The specific suppression of the expression of an mRNA can be achieved by using ribozymes. Ribozymes are RNA molecules able to break and form covalent bonds within a nucleic acid molecule. These molecules, with even greater potential advantages than antisense oligodeoxynucleotides, are able to bind specifically and cleave an mRNA substrate. There are advantages to using ribozymes instead of antisense oligodeoxynucleotides. Ribozymes can inactivate the target RNA without relying on the host cell's machinery and they have the capacity to cleave more than one copy of the target RNA by dissociating from the cleavage products and binding to another target molecule. Most of the studies performed to date have described the use of ribozymes as therapeutic agents for viral and cancer diseases. However, some dominant genetic disorders may also benefit from this approach. This is the case for some connective tissue disorders such as osteogenesis imperfecta, Marfan syndrome and the craniosynostotic syndromes.     

Innateness, evolution, and genetics of language

Our goal in this article is to review a debate over the evolution of language and to suggest some keys to its resolution. We begin with a review of some of the theoretical and empirical evidence for the innateness of language that has caused renewed interest in the evolution of language. In a second section we review some prominent theories of the evolution of language, focusing on the controversy over whether language could have been adapted for some purpose. We argue that for evolutionary studies of language to advance, theorists must make more persuasive arguments for the purpose of language, and, furthermore, linguists must continue to develop a detailed theory of syntax. Finally, we suggest ways that behavioral and population genetics could help to inform studies of the evolution of language.     

Effect of Heat Treatment Process on Mechanical Properties and Microstructure of Modified CNS-Ⅱ F/M Steel

 Ferritic/martensitic (F/M) steels have been recommended as one of the candidate materials for supercritical water cooled reactor (SCWR) in-core components use for its high thermal conductivity, low thermal expansion coefficient and inherently good dimensional stability under irradiation condition in comparison to austenitic steel. CNS-Ⅱ F/M steel which has good mechanical properties was one of the 9-12Cr F/M steels designed for SCWR in the previous work. In this study a modified CNS-Ⅱ F/M steel was used and it′s ultimate tensile strength was 925 MPa at room temperature and 483 MPa at 600 ℃ after optimizing heat treatment parameter. The ductile to brittle transition temperature of modified CNS-Ⅱ F/M steel is -55 ℃. Those are at the same level or even higher than that of CNS-Ⅱ and some commercial F/M steels nominated for SCWR in-core component use. The transmission electron microscope (TEM) results showed that the mechanical properties of the tempered martensite was closely related to the decomposition stage of the martensite.     

Effect of Rare Earth on Fuel Activation of Far Infrared Ceramic

This work relates to a new type of ceramic with far infrared rays emitting function for improving fuel efficiency, and more particularly for enhancing the combustion efficiency. According to the far infrared rays absorption properties of fuel, some rare earth is added to the ceramic to radiate some far infrared rays with special wavelength. And the effect of rare earth on the fuel activation of the ceramic was investigated.. It is shown that the rare earth cooperates with the ceramic improving the far infrared rays radiation ability. The radiance can reach 90%. With the device of the invention, the double bonds between carbon atoms in the hydrocarbon fuel are broken down to form smaller hydrocarbon molecules lowering the volatilization point thereby enhancing the combustion efficiency. According to the test results,the fuel consumption rate is improved by 4.4%. At the same time, deleterious gas output is reduced obviously to achieve energy conservation and prevent environmental pollution.     

Automatic backscatter analysis of regional left ventricular systolic function using color kinesis

Assessment of regional wall motion by 2-dimensional echocardiography can be performed by either semiquantitative wall motion scoring or by quantitative analysis. The former is subjective and requires expertise. Quantitative methods are too time-consuming for routine use in a busy clinical laboratory. Color kinesis is a new algorithm utilizing acoustic backscatter analysis. It provides a color encoded map of endocardial motion in real time. In each frame a new color layer is added; the thickness of the color beam represents endocardial motion during that frame. The end-systolic image has multiple color layers, representing regional and temporal heterogeneity of segmental motion. The purpose of this study was to validate the use of color kinesis for semiquantitative analysis of regional left ventricular systolic function and quantitatively in measurement of endocardial excursion. Semiquantitative wall motion scoring was performed in 18 patients using both 2-dimensional echo and color kinesis. Scoring was identical in 74% of segments; there was 84% agreement in definition of normal vs. abnormal. There was less interobserver variability in wall motion scoring using color kinesis. Endocardial excursion was quantified in 21 patients. 70% of the imaged segments were suitable for analysis. Correlation between 2-dimensional echocardiographic measurements and color kinesis was excellent, r = 0.87. The mean difference in excursion as measured by the 2 methods was -0.05 +/- 2.0 mm. In conclusion, color kinesis is a useful method for assessing regional contraction by displaying a color map of systolic endocardial excursion. This algorithm may improve the confidence and accuracy of assessment of segmental ventricular function by echocardiographic methods.