To see the other types of publications on this topic, follow the link: Sequential ends.
Journal articles on the topic 'Sequential ends'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Sequential ends.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Tavares, Paulo, Rudi Lurz, Asita Stiege, Beate Rückert, and Thomas A. Trautner. "Sequential Headful Packaging and Fate of the Cleaved DNA Ends in Bacteriophage SPP1." Journal of Molecular Biology 264, no. 5 (1996): 954–67. http://dx.doi.org/10.1006/jmbi.1996.0689.
Full text
2
Holzer, Markus, Bianca Truthe, and Ahmad Firdaus Yosman. "On bonded sequential and parallel insertion systems." RAIRO - Theoretical Informatics and Applications 52, no. 2-3-4 (2018): 127–51. http://dx.doi.org/10.1051/ita/2018010.
Full textAbstract:
We introduce a new variant of insertion systems, namely bonded insertion systems. In such systems, words are not only formed by usual letters but also by bonds between letters. Words which can be inserted, have “free” bonds at their ends which control at which positions in a word they can be inserted (namely only there, where the bonds “fit”). Two kinds of bonded insertion systems are defined in this paper: so-called bonded sequential insertion systems and bonded parallel insertion systems. In a sequential system, there is only one word inserted at a time. In a parallel system, there is a word inserted at every possible position in parallel in one time step. We investigate the generative capacity of those two kinds and relate the families of generated languages to some families of the Chomsky hierarchy and to families of languages generated by Lindenmayer systems. Additionally, we investigate some closure properties.
3
Yan, Chongjun, Jiafu Tang, and Bowen Jiang. "Sequential Appointment Scheduling Considering Walk-In Patients." Mathematical Problems in Engineering 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/564832.
Full textAbstract:
This paper develops a sequential appointment algorithm considering walk-in patients. In practice, the scheduler assigns an appointment time for each call-in patient before the call ends, and the appointment time cannot be changed once it is set. Each patient has a certain probability of being a no-show patient on the day of appointment. The objective is to determine the optimal booking number of patients and the optimal scheduling time for each patient to maximize the revenue of all the arriving patients minus the expenses of waiting time and overtime. Based on the assumption that the service time is exponentially distributed, this paper proves that the objective function is convex. A sufficient condition under which the profit function is unimodal is provided. The numerical results indicate that the proposed algorithm outperforms all the commonly used heuristics, lowering the instances of no-shows, and walk-in patients can improve the service efficiency and bring more profits to the clinic. It is also noted that the potential appointment is an effective alternative to mitigate no-show phenomenon.
4
Tachibana, Akira, Kazuo Tohiguchi, Takayuki Ueno, Yuichi Setogawa, Ayako Harada, and Toshizumi Tanabe. "Preparation of long sticky ends for universal ligation-independent cloning: Sequential T4 DNA polymerase treatments." Journal of Bioscience and Bioengineering 107, no. 6 (2009): 668–69. http://dx.doi.org/10.1016/j.jbiosc.2009.01.019.
Full text
5
Mokros, Petr, Jan Vrbsky, and Jiri Siroky. "Identification of chromosomal fusion sites in Arabidopsis mutants using sequential bicolour BAC-FISH." Genome 49, no. 8 (2006): 1036–42. http://dx.doi.org/10.1139/g06-082.
Full textAbstract:
Double stranded chromosomal breaks are repaired by homologous recombination or nonhomologous end joining (NHEJ). When broken chromosome ends are fused together by NHEJ, the resulting dicentric chromosomes can be detected as anaphase bridges during the subsequent mitosis. Telomeres in the absence of functional telomerase shorten, became unprotected, and are eventually recognized by the cell repair system as double stranded breaks. As result, chromosomes of Arabidopsis thaliana plants that are deficient in the gene for telomerase reverse transcriptase (TERT) are prone to chromosome fusions. We use Arabidopsis tert–/– mutants as a model system for analyzing terminal chromosome fusions. Here we report a novel and sensitive cytogenetic assay for the identification and characterization of chromosome-terminal fusion events by employing fluorescence in situ hybridization (FISH) with multiple probes and a repeated hybridization approach. A mixture of chromosome-specific subtelomeric probes is applied successively in 3 FISH reactions to the slides containing mitotic anaphase figures with anaphase bridges. Each figure is registered by a CCD camera after each in situ hybridization procedure. By comparing the signals presented on the bridge in successive images the assessment of the particular chromosome arms involved in fusion is possible. This experimental setup enables unambiguous identification of individual chromosome ends employed in fusion events.Key words: Arabidopsis; BAC probes; AtTERT gene; bicolour FISH; anaphase.
6
Li, Wenchao. "Sequential Voicing in Old Japanese." International Journal of Linguistics 12, no. 5 (2020): 239. http://dx.doi.org/10.5296/ijl.v12i5.17733.
Full textAbstract:
This study tackles sequential voicing in Old Japanese with a focus on three matters: (a) the interaction of the eight vowels and aspirated consonants; (b) the association of the written system and sequential voicing; and (c) the interaction between the combinationality of each constituent and sequential voicing. Four hundred and seventy-two compound nouns of Old Japanese were collected from the corpus ‘The Japanese Lexicon: A Rendaku Encyclopedia’ by NINJAL. The findings reveal that (i) /k/ has the largest token number of sequential voicing and /p/ has the second largest token number, followed by /s/ and /t/; (ii) regarding the eight vowels /a/, /e1/, /e2/, /i1/, /i2/, /o1/, /o2/ and /u/, /a/ is most likely to form a [N1-N2] whose initial consonant is /k/, /p/ and /t/. It is not likely for the vowel /a/ to invite a voiced ‘/s/-initial’ N1’; /o1/ and /o2/ are both likely to combine with a voiced consonant /k/; /t/ and are less likely to yield a voiced /s/; /e1/ is more likely to invite a voiced consonant than /e2/, but /e1/ does not invite a voiced /p/; /e2/ does not yield a voiced /s/; and /i1/ is likely to take a voiced consonant than /i2/. /k/ and /t/ are the two consonants that are most likely to be voiced when forming a N-N with N1 ends with /i1/. /i2/ does not invite a voiced /p/, /s/ or /t/; /u/ never results in a voiced /s/; (iii) there is a split in the characters that renders a voiced phoneme or an unvoiced phoneme; and (iv) the semantic relationship of N1 and N2 in [N1-N2] that bears sequential voicing is of six types, of which the most frequent relationship of N1 and N2 is [Modifier - N2]. The [prefix-N2] construction is not subject to sequential voicing.
7
Singh, Ishwar, Zoya Zarafshani, Frances Heaney, and Jean-François Lutz. "Orthogonal modification of polymer chain-ends via sequential nitrile oxide–alkyne and azide–alkyne Huisgen cycloadditions." Polym. Chem. 2, no. 2 (2011): 372–75. http://dx.doi.org/10.1039/c0py00236d.
Full text
8
Zhang, Jian, Mahjoub Dridi, and Abdellah El Moudni. "A Markov decision model with dead ends for operating room planning considering dynamic patient priority." RAIRO - Operations Research 53, no. 5 (2019): 1819–41. http://dx.doi.org/10.1051/ro/2018110.
Full textAbstract:
This paper addresses an operating room planning problem with surgical demands from both the elective patients and the non-elective ones. A dynamic waiting list is established to prioritize and manage the patients according to their urgency levels and waiting times. In every decision period, sequential decisions are taken by selecting high-priority patients from the waiting list to be scheduled. With consideration of random arrivals of new patients and uncertain surgery durations, the studied problem is formulated as a novel Markov decision process model with dead ends. The objective is to optimize a combinatorial cost function involving patient waiting times and operating room over-utilizations. Considering that the conventional dynamic programming algorithms have difficulties in coping with large-scale problems, we apply several adapted real-time dynamic programming algorithms to solve the proposed model. In numerical experiments, we firstly apply different algorithms to solve the same instance and compare the computational efficiencies. Then, to evaluate the effects of dead ends on the policy and the computation, we conduct simulations for multiple instances with the same problem scale but different dead ends. Experimental results indicate that incorporating dead ends into the model helps to significantly shorten the patient waiting times and improve the computational efficiency.
9
Lenting, Peter J., Olivier D. Christophe, and Cécile V. Denis. "von Willebrand factor biosynthesis, secretion, and clearance: connecting the far ends." Blood 125, no. 13 (2015): 2019–28. http://dx.doi.org/10.1182/blood-2014-06-528406.
Full textAbstract:
Abstract To understand the placement of a certain protein in a physiological system and the pathogenesis of related disorders, it is not only of interest to determine its function but also important to describe the sequential steps in its life cycle, from synthesis to secretion and ultimately its clearance. von Willebrand factor (VWF) is a particularly intriguing case in this regard because of its important auxiliary roles (both intra- and extracellular) that implicate a wide range of other proteins: its presence is required for the formation and regulated release of endothelial storage organelles, the Weibel-Palade bodies (WPBs), whereas VWF is also a key determinant in the clearance of coagulation factor VIII. Thus, understanding the molecular and cellular basis of the VWF life cycle will help us gain insight into the pathogenesis of von Willebrand disease, design alternative treatment options to prolong the factor VIII half-life, and delineate the role of VWF and coresidents of the WPBs in the prothrombotic and proinflammatory response of endothelial cells. In this review, an update on our current knowledge on VWF biosynthesis, secretion, and clearance is provided and we will discuss how they can be affected by the presence of protein defects.
10
Deshpande, Rajashree A., Logan R. Myler, Michael M. Soniat, et al. "DNA-dependent protein kinase promotes DNA end processing by MRN and CtIP." Science Advances 6, no. 2 (2020): eaay0922. http://dx.doi.org/10.1126/sciadv.aay0922.
Full textAbstract:
The repair of DNA double-strand breaks occurs through nonhomologous end joining or homologous recombination in vertebrate cells—a choice that is thought to be decided by a competition between DNA-dependent protein kinase (DNA-PK) and the Mre11/Rad50/Nbs1 (MRN) complex but is not well understood. Using ensemble biochemistry and single-molecule approaches, here, we show that the MRN complex is dependent on DNA-PK and phosphorylated CtIP to perform efficient processing and resection of DNA ends in physiological conditions, thus eliminating the competition model. Endonucleolytic removal of DNA-PK–bound DNA ends is also observed at double-strand break sites in human cells. The involvement of DNA-PK in MRN-mediated end processing promotes an efficient and sequential transition from nonhomologous end joining to homologous recombination by facilitating DNA-PK removal.
11
Raz, V., J. H. Bergervoet, and M. Koornneef. "Sequential steps for developmental arrest in Arabidopsis seeds." Development 128, no. 2 (2001): 243–52. http://dx.doi.org/10.1242/dev.128.2.243.
Full textAbstract:
The continuous growth of the plant embryo is interrupted during the seed maturation processes which results in a dormant seed. The embryo continues development after germination when it grows into a seedling. The embryo growth phase starts after morphogenesis and ends when the embryo fills the seed sac. Very little is known about the processes regulating this phase. We describe mutants that affect embryo growth in two sequential developmental stages. Firstly, embryo growth arrest is regulated by the FUS3/LEC type genes, as mutations in these genes cause a continuation of growth in immature embryos. Secondly, a later stage of embryo dormancy is regulated by ABI3 and abscisic acid; abi3 and aba1 mutants exhibit premature germination only after embryos mature. Mutations affecting both developmental stages result in an additive phenotype and double mutants are highly viviparous. Embryo growth arrest is regulated by cell division activities in both the embryo and the endosperm, which are gradually switched off at the mature embryo stage. In the fus3/lec mutants, however, cell division in both the embryo and endosperm is not arrested, but rather is prolonged throughout seed maturation. Furthermore ectopic cell division occurs in seedlings. Our results indicate that seed dormancy is secured via at least two sequential developmental processes: embryo growth arrest, which is regulated by cell division and embryo dormancy.
12
Rodionov, Sergei, and James E. Overland. "Application of a sequential regime shift detection method to the Bering Sea ecosystem." ICES Journal of Marine Science 62, no. 3 (2005): 328–32. http://dx.doi.org/10.1016/j.icesjms.2005.01.013.
Full textAbstract:
Abstract A common problem of existing methods for regime shift detection is their poor performance at the ends of time-series. Consequently, shifts in environmental and biological indices are usually detected long after their actual appearance. A recently introduced method based on sequential t-test analysis of regime shifts (STARS) treats all incoming data in real time, signals the possibility of a regime shift as soon as possible, then monitors how perception of the magnitude of the shift changes over time. Results of a STARS application to the eastern Bering Sea ecosystem show how the 1989 and 1998 regime shifts manifest themselves in biotic and abiotic indices in comparison with the 1977 shift.
13
Xiao, Xin Cai. "A Novel Structure Having Linear Poly(N-Isopropylacrylamide) Chains with Rapid Response to Temperature Changes." Advanced Materials Research 396-398 (November 2011): 205–8. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.205.
Full textAbstract:
In this article, a novel structure poly(N-isopropylacrylamide) (PNIPAM) hydrogel, which is featured with both ends of linear PNIPAM chains being grafted onto semicircular and cross-linked PNIPAM chains, has been successfully prepared in a three-step process by a method of sequential synthesis for the first time. The proposed hydrogel displays faster and hydration/dehydration dynamic response to temperature cycling owing to linear PNIPAM chains to form big-hole structure. This work may be highly attractive for targeting drug delivery systems, polymeric machinery, and sensors and so on.
14
Vorobjev, I. A., V. I. Rodionov, I. V. Maly, and G. G. Borisy. "Contribution of plus and minus end pathways to microtubule turnover." Journal of Cell Science 112, no. 14 (1999): 2277–89. http://dx.doi.org/10.1242/jcs.112.14.2277.
Full textAbstract:
Turnover is important for the maintenance and remodeling of the cytoskeleton during the processes of cell morphogenesis, mitosis and motility. Microtubule (MT) turnover is thought to occur by dynamic instability, growth and shortening at distal (plus) ends. Recent observation of MT release from the centrosome and depolymerization from proximal (minus) ends indicates the existence of a minus end pathway. To evaluate the relative contributions of plus and minus end pathways to turnover, we analyzed MT dynamics in a model system, the fish melanophore, a large non-motile cell with a regular radial array of long MTs. MT ends were tracked in digital fluorescence time-lapse sequences and life histories of individual MTs were analyzed using random walk theory generalized to the case of diffusion with drift. Analysis of plus end dynamics gave an apparent diffusion coefficient of D=7.5 microm2/minute. The random walk model predicts that the half-time for turnover driven solely by plus end dynamics will depend strongly on position in the cell. Based on the experimentally determined value of D, turnover of MTs near the center of a typical melanophore of radius 70 microm was calculated to require over 5 hours, a paradoxically long time. To examine MT behavior deep in the cytoplasm, we developed a novel, sequential subtraction mode of image analysis. This analysis revealed a subpopulation of MTs which shortened from their minus ends, presumably after constitutive release from the centrosome. Given the relative slowness of plus end dynamics to turn over the root of a long MT, the turnover of MTs near the cell center is determined primarily by the minus-end pathway. MTs released from the centrosome become replaced by newly nucleated ones. The relative contributions of plus and minus end pathways was estimated from the diffusion coefficient, D, for the plus end, the length distribution of MTs, t he frequency of free minus ends, and the rate of minus-end shortening. We conclude that, in large animal cells with a centrosomally focussed array of MTs, turnover occurs by a combination of plus and minus end pathways, the plus end dominating at the cell periphery and the minus end dominating near the cell center.
15
Filipi, Anna. "A Toddler’s treatment of MM and MM HM in talk with a parent." Language as Action 30, no. 3 (2007): 33.1–33.17. http://dx.doi.org/10.2104/aral0733.
Full textAbstract:
The study to be reported in this paper examined the work accomplished by mm and mm hm in the interactions of a parent and his daughter aged 0;10–2;0. Using the findings of Gardner (2001) for adults, the analysis shows that mm accomplished a range of functions based on its sequential placement and prosodic features, whereas mm hm was much more restricted to its use as a continuer. The principal concern of the study, however, was to investigate how the child treated these tokens in next turn position. It was found that she was able to display her acceptance or rejection of the response and that she had acquired a stock of conversational resources to do so. Included in the stock were the ability to initiate self and other repair, to correct, and to initiate a new topic to mark completion of a sequence. It is argued that through these actions the child was offering a display of her understanding of sequential connections and appropriateness of fit, and importantly what she deemed to be a sufficient response. The paper ends with a discussion of the child’s emerging knowledge as it is revealed in the minutiae of interaction.
16
Filipi, Anna. "A Toddler’s treatment of MM and MM HM in talk with a parent." Language as Action 30, no. 3 (2007): 33.1–33.17. http://dx.doi.org/10.1075/aral.30.3.04fil.
Full textAbstract:
The study to be reported in this paper examined the work accomplished bymmandmm hmin the interactions of a parent and his daughter aged 0;10–2;0. Using the findings of Gardner (2001) for adults, the analysis shows thatmmaccomplished a range of functions based on its sequential placement and prosodic features, whereasmm hmwas much more restricted to its use as a continuer. The principal concern of the study, however, was to investigate how the child treated these tokens in next turn position. It was found that she was able to display her acceptance or rejection of the response and that she had acquired a stock of conversational resources to do so. Included in the stock were the ability to initiate self and other repair, to correct, and to initiate a new topic to mark completion of a sequence. It is argued that through these actions the child was offering a display of her understanding of sequential connections and appropriateness of fit, and importantly what she deemed to be a sufficient response. The paper ends with a discussion of the child’s emerging knowledge as it is revealed in the minutiae of interaction.
17
Cho, B. C., C. N. Chang, S. L. Liaw, and P. T. Huang. "The feasible sequential control strategy of treating high strength organic nitrogen wastewater with sequencing batch biofilm reactor." Water Science and Technology 43, no. 3 (2001): 115–22. http://dx.doi.org/10.2166/wst.2001.0126.
Full textAbstract:
The bio-kinetics and feasible sequential control strategy of treating high strength organic carbon and nitrogen wastewater were investigated by conducting the ABS manufacturing wastewater in a series of Sequencing Batch Biofilm Reactors (SBBRs). The on-line ORP, pH, and DO monitoring parameters were applied to identify the feature-points when ammonification, nitrification, and denitrification ends. The carbonaceous matter removal kinetics in the anaerobic and aerobic reaction stages can be expressed by the Michaelis-Menten equation. High efficiency of organic carbon removal and organic nitrogen ammonification in the anaerobic stage can eliminate the substrate competition and activation inhibition to nitrifying organisms in the following aerobic stage. In the sequencing nitrogen removal processes, the producing time and system ORP values of these feature-points have good function relationships with the influent COD loading rates of SBBR, which can be integrated into a set-point (set-time and set-ORP) sequential control strategy of nitrogen removal. The automatic control operation results revealed ORP was one of the major control parameters of the sequencing nitrogen removal process in SBBR system and high overall removal efficiency were obtained.
18
Widłak, P. "The DFF40/CAD endonuclease and its role in apoptosis." Acta Biochimica Polonica 47, no. 4 (2000): 1037–44. http://dx.doi.org/10.18388/abp.2000_3957.
Full textAbstract:
The sequential generation of large-scale DNA fragments followed by internucleosomal chromatin fragmentation is a biochemical hallmark of apoptosis. One of the nucleases primarily responsible for genomic DNA fragmentation during apoptosis is called DNA Fragmentation Factor 40 (DFF40) or Caspase-activated DNase (CAD). DFF40/CAD is a magnesium-dependent endonuclease specific for double stranded DNA that generates double strand breaks with 3'-hydroxyl ends. DFF40/CAD is activated by caspase-3 that cuts the nuclease's inhibitor DFF45/ICAD. The nuclease preferentially attacks chromatin in the internucleosomal linker DNA. However, the nuclease hypersensitive sites can be detected and DFF40/CAD is potentially involved in large-scale DNA fragmentation as well. DFF40/CAD-mediated DNA fragmentation triggers chromatin condensation that is another hallmark of apoptosis.
19
Fellah Jahromi, Ali, Rama B. Bhat, and Wen-Fang Xie. "Frequency Dependent Spencer Modeling of Magnetorheological Damper Using Hybrid Optimization Approach." Shock and Vibration 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/382541.
Full textAbstract:
Magnetorheological dampers have been widely used in civil and automotive industries. The nonlinear behavior of MR fluid makes MR damper modeling a challenging problem. In this paper, a frequency dependent MR damper model is proposed based on Spencer MR damper model. The parameters of the model are identified using an experimental data based hybrid optimization approach which is a combination of Genetic Algorithm and Sequential Quadratic Programming approach. The frequency in the proposed model is calculated using measured relative velocity and relative displacement between MR damper ends. Therefore, the MR damper model will be function of frequency. The mathematical model is validated using the experimental results which confirm the improvement in the accuracy of the model and consistency in the variation damping with the frequency.
20
SPRAGUE, ALAN P., and TADAO TAKAOKA. "O(1) QUERY TIME ALGORITHM FOR ALL PAIRS SHORTEST DISTANCES ON INTERVAL GRAPHS." International Journal of Foundations of Computer Science 10, no. 04 (1999): 465–72. http://dx.doi.org/10.1142/s0129054199000320.
Full textAbstract:
We present an algorithm for the All Pairs Shortest Distance problem on an interval graph on n vertices: after O(n) preprocessing time, the algorithm can deliver a response to a distance query in O(1) time. The method used here is simpler than the method of Chen et al. [4], which has the same preprocessing and query time. It is assumed that an interval model for the graph is given, and ends of intervals are already sorted by coordinate. The preprocessing algorithm can be executed in the EREW PRAM model in O( log n) time, using n/ log n processors. These algorithms (sequential and parallel) may be extended to circular arc graphs, with the same time and processor bounds.
21
Kim, Yong Hwan, Tae Keun Kwon, Sungsoon Park, et al. "Trehalose Synthesis by Sequential Reactions of Recombinant Maltooligosyltrehalose Synthase and Maltooligosyltrehalose Trehalohydrolase from Brevibacterium helvolum." Applied and Environmental Microbiology 66, no. 11 (2000): 4620–24. http://dx.doi.org/10.1128/aem.66.11.4620-4624.2000.
Full textAbstract:
ABSTRACT A DNA fragment encoding two enzymes leading to trehalose biosynthesis, maltooligosyltrehalose synthase (BvMTS) and maltooligosyltrehalose trehalohydrolase (BvMTH), was cloned from the nonpathogenic bacterium Brevibacterium helvolum. The open reading frames for the two proteins are 2,331 and 1,770 bp long, respectively, and overlap by four nucleotides. RecombinantBvMTS, BvMTH, and fusion geneBvMTSH, constructed by insertion of an adenylate in the overlapping region, were expressed in Escherichia coli. Purified BvMTS protein catalyzed conversion of maltopentaose to maltotriosyltrehalose, which was further hydrolyzed by BvMTH protein to produce trehalose and maltotriose. The enzymes shortened maltooligosaccharides by two glucose units per cycle of sequential reactions and released trehalose. Maltotriose and maltose were not catalyzed further and thus remained in the reaction mixtures depending on whether the substrates had an odd or even number of glucose units. The bifunctional in-frame fusion enzyme, BvMTSH, catalyzed the sequential reactions more efficiently than an equimolar mixture of the two individual enzymes did, presumably due to a proximity effect on the catalytic sites of the enzymes. The recombinant enzymes produced trehalose from soluble starch, an abundant natural source for trehalose production. Addition of α-amylase to the enzyme reaction mixture dramatically increased trehalose production by partial hydrolysis of the starch to provide more reducing ends accessible to the BvMTS catalytic sites.
22
Okulu, Hasan Zuhtu, and Ayse Oguz Unver. "The Process of Facilitating Knowledge Acquisition and Retention: An Inquiry into Magnetic Poles with Challenging Questions." International Education Studies 11, no. 5 (2018): 25. http://dx.doi.org/10.5539/ies.v11n5p25.
Full textAbstract:
The current research is to give an example to the inquiry-based science teaching implementations for facilitating knowledge acquisition and retention in a short period of time. Thus, the aim of the research is to transfer of acquired knowledge into different situations using sequential inquiry activities, which have challenging questions for inquiry about what the magnetic pole is and how to discover it. The research was designed as a pre-experimental, one-group pre-test/post-test (N=65) with a retention-test. Sequential inquiry-based science activities were applied to provide a series of developmentally appropriate experiences and discussions, which concretely scaffold participant’s ideas of magnetism. According to the results, the participants interpreted the magnets and magnetic poles regarding their functions. The common view of the participants was that a magnetic pole should be at the ends. This view is associated with upper-lower or internal-external surfaces for a ring magnet. Finally, with a sphere magnet, both upper-lower or internal-external surfaces have lost their functions and the inquiry begins with the question “How to find the poles of a magnet?” In that process, students get to engage and feel that they do not know something that they should know.
23
Kolmer, Marek, Ann-Kristin Steiner, Irena Izydorczyk, et al. "Rational synthesis of atomically precise graphene nanoribbons directly on metal oxide surfaces." Science 369, no. 6503 (2020): 571–75. http://dx.doi.org/10.1126/science.abb8880.
Full textAbstract:
Atomically precise graphene nanoribbons (GNRs) attract great interest because of their highly tunable electronic, optical, and transport properties. However, on-surface synthesis of GNRs is typically based on metal surface–assisted chemical reactions, where metallic substrates strongly screen their designer electronic properties and limit further applications. Here, we present an on-surface synthesis approach to forming atomically precise GNRs directly on semiconducting metal oxide surfaces. The thermally triggered multistep transformations preprogrammed in our precursors’ design rely on highly selective and sequential activations of carbon-bromine (C-Br) and carbon-fluorine (C-F) bonds and cyclodehydrogenation. The formation of planar armchair GNRs terminated by well-defined zigzag ends is confirmed by scanning tunneling microscopy and spectroscopy, which also reveal weak interaction between GNRs and the rutile titanium dioxide substrate.
24
Yan, Qiong Jiao. "Preparation and Thermosensitivity of Poly(N-Isopropylacrylamide) Hydrogels with Graded Structure." Advanced Materials Research 568 (September 2012): 400–403. http://dx.doi.org/10.4028/www.scientific.net/amr.568.400.
Full textAbstract:
A novel graded hydrogel based on poly(N-isopropylacrylamide) (PNIPAM), which is characterized with both ends of slightly cross-linked PNIPAM chains being grafted onto cross-linked PNIPAM chains, has been successfully prepared in a three-step process by a method of sequential synthesis for the first time in this paper. In the preparation of the graded hydrogels, with decreasing the crosslinker dosage, the swelling ratio of the hydrogel increased. The graded hydrogel displays faster and hydration/dehydration dynamic response to temperature cycling owing to slightly cross-linked PNIPAM chains to form big-hole structure. The proposed hydrogel structure provide a new mode of the phase transition behavior for thermo-sensitive "smart" or "intelligent" monodisperse micro-actuators, which is highly attractive for targeting drug delivery systems, chemical separations, sensors and so on.
25
Kalyan Chakravathy, P., K. Vasavi Devi, T. Sai Sri, and SK Abu Saleha. "An efficient and secured approach for sequential and transparent identity validation of user in internet services." International Journal of Engineering & Technology 7, no. 1.1 (2017): 664. http://dx.doi.org/10.14419/ijet.v7i1.1.10823.
Full textAbstract:
These days, it ends up noticeably genuine worry to give greater security to web administrations. Along these lines, secure client verification is the central assignment in security frameworks. Generally, a large portion of the frameworks depend on sets of username and secret key which checks the personality of client just at authentication stage. Once the client accesses with username and secret key, no checks are performed and encourages amid working sessions. Be that as it may, rising biometric arrangements gives the username and secret key using biometric information of client. In such approach, single shot check is less proficient in light of the fact that personality of client is perpetually amid entire session. Consequently, an important arrangement is to utilize brief time of timeouts for every session and occasionally ask the client to enter his or her qualifications again and again. In any case, this isn't a legitimate arrangement since it vigorously influences the administration convenience and eventually the fulfilment of clients. This paper investigates the framework for nonstop verification of client utilizing his accreditations, for example, biometric qualities. The utilization of consistent biometric verification framework procures certifications without expressly telling the client or requiring client communication that is, straightforwardly which is essential to ensure for better execution and administration ease of use.
26
SELTING, MARGRET. "The construction of units in conversational talk." Language in Society 29, no. 4 (2000): 477–517. http://dx.doi.org/10.1017/s0047404500004012.
Full textAbstract:
The notion of Turn-Constructional Unit (TCU) in Conversation Analysis has become unclear for many researchers. The underlying problems inherent in the definition of this notion are here identified, and a possible solution is suggested. This amounts to separating more clearly the notions of TCU and Transition Relevance Place (TRP). In this view, the TCU is defined as the smallest interactionally relevant complete linguistic unit, in a given context, that is constructed with syntactic and prosodic resources within their semantic, pragmatic, activity-type-specific, and sequential conversational context. It ends in a TRP unless particular linguistic and interactional resources are used to project and postpone the TRP to the end of a larger multi-unit turn. This suggestion tries to spell out some of the assumptions that the seminal work in CA made in principle, but never formulated explicitly.
27
Olson, Gary E., Virginia P. Winfrey, Kristina E. Hill, and Raymond F. Burk. "Sequential development of flagellar defects in spermatids and epididymal spermatozoa of selenium-deficient rats." Reproduction 127, no. 3 (2004): 335–42. http://dx.doi.org/10.1530/rep.1.00103.
Full textAbstract:
In this study cauda epididymal spermatozoa of rats maintained on a selenium-deficient diet for 5 and 7 months exhibited an array of flagellar defects. Spermatids and spermatozoa were analyzed by light and electron microscopy to define the appearance of flagellar abnormalities during spermiogenesis and post-testicular sperm development. Late spermatids of selenium-deficient rats displayed normal structural organization of the flagellar plasma membrane, axoneme, outer dense fibers, fibrous sheath and annulus, but they exhibited a premature termination of the mitochondrial sheath. A comparison of late spermatids and caput epididymal spermatozoa revealed that a late step in flagellar differentiation was the structural remodeling of the annulus and its accompanying fusion with both the fibrous sheath and the mitochondrial sheath. In selenium-deficient animals, however, the annulus failed to fuse with the mitochondrial sheath, generating an apparent weak point in the flagellum. After epididymal passage, cauda epididymal spermatozoa of selenium-deficient animals also exhibited extensive flagellar disorganization resulting from the apparent sliding and extrusion of specific outer dense fiber–doublet microtubule complexes from the proximal and the distal ends of the mitochondrial sheath and the accompanying loss of the midpiece plasma membrane. Only fiber complex number 4 was extruded proximally, whereas fibers 4, 5, 6 and 7 were extruded from the mitochondrial sheath-deficient posterior midpiece. Axonemal fibers 8, 9, 1, 2 and 3 retained their normal geometric relationships. These data suggest that the known loss of male fertility in selenium deficiency results from the sequential development of sperm defects expressed during both spermiogenesis and maturation in the epididymis.
28
SLANTCHEV, BRANISLAV L. "The Principle of Convergence in Wartime Negotiations." American Political Science Review 97, no. 4 (2003): 621–32. http://dx.doi.org/10.1017/s0003055403000911.
Full textAbstract:
If war results from disagreement about relative strength, then it ends when opponents learn enough about each other. Learning occurs when information is revealed by strategically manipulable negotiation behavior and nonmanipulable battlefield outcomes. I present a model of simultaneous bargaining and fighting where both players can make offers and asymmetric information exists about the distribution of power. In the Markov perfect sequential equilibrium, making and rejecting offers has informational value that outweighs the one provided by the battlefield. However, states use both sources of information to learn and settle before military victory. The Principle of Convergence posits that warfare ceases to be useful when it loses its informational content and that belief in defeat (victory) is not necessary to terminate (initiate) hostilities. Thus, the standard puzzle in international relations that seeks to account for prewar optimism on both sides may not be that relevant.
29
Sanders, Robert E. "A tale of two intentions." Pragmatics and Society 6, no. 4 (2015): 475–501. http://dx.doi.org/10.1075/ps.6.4.01san.
Full textAbstract:
Speaker intention is conceptualized as a property of utterances in context, not speakers; it is based on communally shared knowledge of discursive means to ends. The article’s main theoretical claim is that utterances, in addition to being produced with an intention about their pragmatic meaning, are also produced with an intention to bring about some post-interactional end result. Both types of intention bear on the utterance’s pragmatic meaning. Empirical aspects of the theoretical difference between these two types of speaker intention are shown through analysis of naturally occurring interactions; here, the analytical focus is on the scope, interdependence, recognizability, and fulfillment of each type of intention, with special attention to the functionality of an utterance’s content, composition, and sequential placement as a means of getting a response from the interlocutor(s) that goes along with what the speaker intends as regards the end result of the interaction.
30
Linshaw, M. A., L. W. Welling, and C. A. Bauman. "Basolateral membrane properties of juxtamedullary proximal tubule in newborn rabbit." American Journal of Physiology-Renal Physiology 251, no. 2 (1986): F208—F213. http://dx.doi.org/10.1152/ajprenal.1986.251.2.f208.
Full textAbstract:
We have evaluated the functional and morphological changes that occur in juxtamedullary proximal convoluted tubules before and after the completion of nephrogenesis at approximately 3 wk of age. Tubules were dissected in connection with glomeruli in the deep juxtamedullary zone, crimped at both ends, and induced to swell in isotonic medium by sequential exposure to ouabain, reduced bath protein concentration, and collagenase. Basolateral membrane surface areas were measured morphometrically in paired tubules if possible. The swelling rates and basolateral areas were the same in tubules from 2-7- and 14-17-day-old rabbits (during nephrogenesis), had increased in 28-42-day-old rabbits (after nephrogenesis), and increased further in adults. Because the surface areas and swelling rates increased proportionally, the nephrons “matured” only after nephrogenesis was complete and then only in basolateral surface area. The intrinsic membrane properties of hydraulic conductivity and ion permeability apparently remained constant.
31
Harmon, Shawn B., A. George Megaw, and Gail W. Wertz. "RNA Sequences Involved in Transcriptional Termination of Respiratory Syncytial Virus." Journal of Virology 75, no. 1 (2001): 36–44. http://dx.doi.org/10.1128/jvi.75.1.36-44.2001.
Full textAbstract:
ABSTRACT RNA signals at the ends of the genes of respiratory syncytial (RS) virus direct polyadenylation and termination of viral transcription. These gene ends contain two conserved regions, a pentanucleotide and a tract of uridylate (U) residues, separated by an A/U-rich central region that is less well conserved. The U tract is thought to be the template for polyadenylation of viral mRNAs by reiterative transcription. The cis-acting requirements for termination were investigated by mutagenesis of the matrix (M) gene end (3′-UCAAUUAUUUUUU-5′) in a dicistronic RNA replicon. Termination efficiencies were quantitated by intracellular metabolic labeling of monocistronic mRNAs and the dicistronic readthrough RNAs that result when termination fails to occur. All three regions of the gene end were necessary for termination. Mutation of each of the first 8 nucleotides of the M gene end to all other nucleotides showed that nucleotides 2 to 6 were important for termination and intolerant of change, whereas nucleotides 1 and 7 were tolerant of change. At position 8, A or U allowed termination, but G or C did not. Both the length and the position of the U tract were important for termination. U residues at positions 9 to 12 were necessary, while additional U residues at position 8, and especially position 13, enhanced termination efficiency. Altering the length of the central region abolished termination, suggesting that the position of the U tract with respect to the 3′-UCAAU-5′ sequence was critical. The termination efficiencies of each of the 10 genes of RS virus are different. Since transcription is obligatorily sequential and termination of each gene is required for transcription of the next gene downstream, these differences may contribute to gene regulation. In agreement with our data, the naturally occurring gene ends of RS virus that terminate inefficiently have short U tracts or other sequence features that correlated with decreased termination when similar mutations were analyzed in RNA replicons.
32
Wilson-Kubalek, Elizabeth M., Iain M. Cheeseman, Craig Yoshioka, Arshad Desai, and Ronald A. Milligan. "Orientation and structure of the Ndc80 complex on the microtubule lattice." Journal of Cell Biology 182, no. 6 (2008): 1055–61. http://dx.doi.org/10.1083/jcb.200804170.
Full textAbstract:
The four-subunit Ndc80 complex, comprised of Ndc80/Nuf2 and Spc24/Spc25 dimers, directly connects kinetochores to spindle microtubules. The complex is anchored to the kinetochore at the Spc24/25 end, and the Ndc80/Nuf2 dimer projects outward to bind to microtubules. Here, we use cryoelectron microscopy and helical image analysis to visualize the interaction of the Ndc80/Nuf2 dimer with microtubules. Our results, when combined with crystallography data, suggest that the globular domain of the Ndc80 subunit binds strongly at the interface between tubulin dimers and weakly at the adjacent intradimer interface along the protofilament axis. Such a binding mode, in which the Ndc80 complex interacts with sequential α/β-tubulin heterodimers, may be important for stabilizing kinetochore-bound microtubules. Additionally, we define the binding of the Ndc80 complex relative to microtubule polarity, which reveals that the microtubule interaction surface is at a considerable distance from the opposite kinetochore-anchored end; this binding geometry may facilitate polymerization and depolymerization at kinetochore-attached microtubule ends.
33
Sawada, Y., DN Fass, JA Katzmann, RC Bahn, and EJ Bowie. "Hemostatic plug formation in normal and von Willebrand pigs: the effect of the administration of cryoprecipitate and a monoclonal antibody to Willebrand factor." Blood 67, no. 5 (1986): 1229–39. http://dx.doi.org/10.1182/blood.v67.5.1229.1229.
Full textAbstract:
Abstract Hemostatic plug (HP) formation was investigated in the ear bleeding time incision in normal and von Willebrand pigs. HP volume was calculated by integrating the areas of serial sections. In normal pigs (n = 11), platelets immediately formed a layer on the surface of the cut channel. Platelet aggregates formed at the ends of transected vessels and gradually enlarged. Finally, all transected vessels were occluded by HP and bleeding stopped. In contrast, large HPs were formed in the incision in von Willebrand's disease (vWD) pigs (n = 4); these HPs did not cover the ends of the transected vessels, which continued to bleed, allowing the formation of large hemostatically ineffective platelet aggregates in the incision. Canals traversed these HPs, and bleeding from the open vessels may have continued through them. After infusion of cryoprecipitate into a vWD pig, the bleeding time shortened, and the morphological findings of the HPs were similar to those of normal pigs. In normal pigs (n = 3) infused with an anti- Willebrand factor monoclonal antibody, which prolonged the bleeding time, a large HP formed in the incision, similar to that observed in the vWD pig. The volume of the normal and vWD HPs increased with time. These in vivo findings suggest that Willebrand factor is involved in the localization of the HP to the damaged vessel and may also play a role in platelet-platelet interaction. A computerized morphometric technique was used for measuring the volume of the hemostatic plugs and the distance of sequential points on the perimeter of the HP from the center of selected bleeding vessels.
34
Sawada, Y., DN Fass, JA Katzmann, RC Bahn, and EJ Bowie. "Hemostatic plug formation in normal and von Willebrand pigs: the effect of the administration of cryoprecipitate and a monoclonal antibody to Willebrand factor." Blood 67, no. 5 (1986): 1229–39. http://dx.doi.org/10.1182/blood.v67.5.1229.bloodjournal6751229.
Full textAbstract:
Hemostatic plug (HP) formation was investigated in the ear bleeding time incision in normal and von Willebrand pigs. HP volume was calculated by integrating the areas of serial sections. In normal pigs (n = 11), platelets immediately formed a layer on the surface of the cut channel. Platelet aggregates formed at the ends of transected vessels and gradually enlarged. Finally, all transected vessels were occluded by HP and bleeding stopped. In contrast, large HPs were formed in the incision in von Willebrand's disease (vWD) pigs (n = 4); these HPs did not cover the ends of the transected vessels, which continued to bleed, allowing the formation of large hemostatically ineffective platelet aggregates in the incision. Canals traversed these HPs, and bleeding from the open vessels may have continued through them. After infusion of cryoprecipitate into a vWD pig, the bleeding time shortened, and the morphological findings of the HPs were similar to those of normal pigs. In normal pigs (n = 3) infused with an anti- Willebrand factor monoclonal antibody, which prolonged the bleeding time, a large HP formed in the incision, similar to that observed in the vWD pig. The volume of the normal and vWD HPs increased with time. These in vivo findings suggest that Willebrand factor is involved in the localization of the HP to the damaged vessel and may also play a role in platelet-platelet interaction. A computerized morphometric technique was used for measuring the volume of the hemostatic plugs and the distance of sequential points on the perimeter of the HP from the center of selected bleeding vessels.
35
Kriatchko, Aleksei N., Dirk K. Anderson, and Patrick C. Swanson. "Identification and Characterization of a Gain-of-Function RAG-1 Mutant." Molecular and Cellular Biology 26, no. 12 (2006): 4712–28. http://dx.doi.org/10.1128/mcb.02487-05.
Full textAbstract:
ABSTRACT RAG-1 and RAG-2 initiate V(D)J recombination by cleaving DNA at recombination signal sequences through sequential nicking and transesterification reactions to yield blunt signal ends and coding ends terminating in a DNA hairpin structure. Ubiquitous DNA repair factors then mediate the rejoining of broken DNA. V(D)J recombination adheres to the 12/23 rule, which limits rearrangement to signal sequences bearing different lengths of DNA (12 or 23 base pairs) between the conserved heptamer and nonamer sequences to which the RAG proteins bind. Both RAG proteins have been subjected to extensive mutagenesis, revealing residues required for one or both cleavage steps or involved in the DNA end-joining process. Gain-of-function RAG mutants remain unidentified. Here, we report a novel RAG-1 mutation, E649A, that supports elevated cleavage activity in vitro by preferentially enhancing hairpin formation. DNA binding activity and the catalysis of other DNA strand transfer reactions, such as transposition, are not substantially affected by the RAG-1 mutation. However, 12/23-regulated synapsis does not strongly stimulate the cleavage activity of a RAG complex containing E649A RAG-1, unlike its wild-type counterpart. Interestingly, wild-type and E649A RAG-1 support similar levels of cleavage and recombination of plasmid substrates containing a 12/23 pair of signal sequences in cell culture; however, E649A RAG-1 supports about threefold more cleavage and recombination than wild-type RAG-1 on 12/12 plasmid substrates. These data suggest that the E649A RAG-1 mutation may interfere with the RAG proteins' ability to sense 12/23-regulated synapsis.
36
McSherry, Troy D., and Paul R. Mueller. "Xenopus Cds1 Is Regulated by DNA-Dependent Protein Kinase and ATR during the Cell Cycle Checkpoint Response to Double-Stranded DNA Ends." Molecular and Cellular Biology 24, no. 22 (2004): 9968–85. http://dx.doi.org/10.1128/mcb.24.22.9968-9985.2004.
Full textAbstract:
ABSTRACT The checkpoint kinase Cds1 (Chk2) plays a key role in cell cycle checkpoint responses with functions in cell cycle arrest, DNA repair, and induction of apoptosis. Proper regulation of Cds1 is essential for appropriate cellular responses to checkpoint-inducing insults. While the kinase ATM has been shown to be important in the regulation of human Cds1 (hCds1), here we report that the kinases ATR and DNA-dependent protein kinase (DNA-PK) play more significant roles in the regulation of Xenopus Cds1 (XCds1). Under normal cell cycle conditions, nonactivated XCds1 constitutively associates with a Xenopus ATR complex. The association of XCds1 with this complex does not require a functional forkhead activation domain but does require a putative SH3 binding region that is found in XCds1. In response to double-stranded DNA ends, the amino terminus of XCds1 is rapidly phosphorylated in a sequential pattern. First DNA-PK phosphorylates serine 39, a site not previously recognized as important in Cds1 regulation. Xenopus ATM, ATR, and/or DNA-PK then phosphorylate three consensus serine/glutamine sites. Together, these phosphorylations have the dual function of inducing dissociation from the ATR complex and independently promoting the full activation of XCds1. Thus, the checkpoint-mediated activation of XCds1 requires phosphorylation by multiple phosphoinositide 3-kinase-related kinases, protein-protein dissociation, and autophosphorylation.
37
Chalyi, S. F., and V. O. Leshchynskyi. "Temporal Patterns Of User Preferences In The Tasks Of Forming Explanations In The Recommender System." Bionics of Intelligence 2, no. 95 (2020): 21–27. http://dx.doi.org/10.30837/bi.2020.2(95).03.
Full textAbstract:
The problem of taking into account changes in the user’s behavior of the recommendation system whenconstructing explanations for recommendations is considered. This problem occurs as a result of cyclical changes in userrequirements. Its solution is associated with the construction of an explanation comparing the alternative choices of theuser of the recommendation system. The developed models of temporal patterns consist of a set of temporal relationshipsbetween the events of users’ choice of goods and services. The first pattern contains an alternative in the form of sequential selection in time of several objects or the selection of only a pair - the first and the last object. The second pattern,sequential-alternative choice, consists of a sequence of choices over time, which ends with the first pattern. The proposedapproach to the formation of patterns is based on the construction of data sets containing temporal dependencies betweena group of user choices for a given level of time detail. The temporal dataset is used to construct a temporal graph of therecommender system user selection process. The latter includes a set of temporal patterns with an indication of the timeof their beginning and end, which makes it possible to determine the duration of the implementation of these patterns.On the basis of the patterns, subsets of temporal relationships are formed to build explanations for the recommendedlist of goods and services. Experimental verification of the developed approach using the “Online Retail” sales data sethas shown the possibility of identifying temporal patterns even on short initial samples.
38
Artemiev, A. A., P. A. Ivanov, A. M. Kashoob, et al. "Shorting Resection and Correction of the Leg Length in the Treatment of Posttramatic Tibial Defects Complicated by Osteomyelitis." Russian Sklifosovsky Journal "Emergency Medical Care" 10, no. 2 (2021): 309–17. http://dx.doi.org/10.23934/2223-9022-2021-10-2-309-317.
Full textAbstract:
Background. Severe fractures of the shin bones are often accompanied by the formation of defects in the tibia, suppuration and soft tissue necrosis. In the case of surgical treatment of fractures, infectious complications reach 3.6-9.1%. One of the methods of treatment of infected defects is resection of the ends of the tibia with shortening. This operation has proven to be effective in the treatment of fresh fractures. The relevance of the work is due to the prospects of using this technique in the treatment of the consequences of fractures with the formation of infected defects of the tibia.Aim of the study. Improving the results of treatment of patients with post-traumatic defects of the tibia complicated by osteomyelitis by performing a shortening resection with simultaneous or sequential correction of the segment length.Material and methods. The results of treatment of 65 patients with diaphyseal post-traumatic tibial defects complicated by osteomyelitis were analysed. They were divided into 2 groups. Group 1 was formed by 31 (47.7%) patients, they underwent shortening resection of the ends of bone fragments in the defect zone with simultaneous lengthening at another level. Group 2 included 34 (52.3%) patients who underwent a shortening resection of the tibia without lengthening. In all cases, the Ilizarov apparatus was used as a fixator.Results. The technique for assessing the size of the true defect of the tibia was optimized taking into account the initial shortening of the segment and the distance between the proximal and distal fragments after resection of their ends. A treatment regimen was developed depending on the level of localization of the tibial defect, and the results of treatment of patients in the compared groups were assessed.Conclusion. Shortening resection is an effective treatment for patients with post-traumatic tibial defects complicated by osteomyelitis. Depending on the level of localization of the defect, it is advisable to carry out treatment according to one of two possible options. When the defect is localized in the upper and middle third of the tibia, shortening resection in an isolated form is shown. If the defect is localized in the lower third of the tibia, it is possible to supplement the shortening resection with an osteotomy in the upper third with Ilizarov lengthening.
39
OGANESSIAN, YURI. "SYNTHESIS OF HEAVIEST ELEMENTS (RESULTS AND PROSPECTS)." International Journal of Modern Physics E 16, no. 04 (2007): 949–56. http://dx.doi.org/10.1142/s0218301307006411.
Full textAbstract:
The formation and decay properties of the heaviest nuclei with Z = 112 - 116 and 118 were studied in the reactions 238 U , 242,244 Pu , 243 Am , 245,248 Cm and 249 Cf +48 Ca . The new nuclides mainly undergo sequential α-decay, which ends with spontaneous fission. The total time of decays ranges from 0.5 ms to about 1 day, depending on the proton and neutron numbers in the synthesized nuclei. The atomic number of the new elements 115 and 113 was confirmed also by an independent radiochemical experiment based on the identification of the neutron-rich isotope 268 Db (TSF ≈ 30 h ), the final product in the chain of α-decays of the odd–odd parent nucleus 288115. The comparison of the decay properties of 29 new nuclides with Z = 104 - 118 and N = 162 - 177 gives evidence for the decisive influence of the structure of superheavy nuclei on their stability with respect to different modes of radioactive decay. The investigations connected with the search for superheavy elements in Nature (cosmic rays) and prospects of superheavy element research are also presented.
40
Sha, Qian-Qian, Jue Zhang, and Heng-Yu Fan. "A story of birth and death: mRNA translation and clearance at the onset of maternal-to-zygotic transition in mammals†." Biology of Reproduction 101, no. 3 (2019): 579–90. http://dx.doi.org/10.1093/biolre/ioz012.
Full textAbstract:
Abstract In mammals, maternal-to-zygotic transition (MZT), or oocyte-to-embryo transition, begins with oocyte meiotic resumption due to the sequential translational activation and destabilization of dormant maternal transcripts stored in the ooplasm. It then continues with the elimination of maternal transcripts during oocyte maturation and fertilization and ends with the full transcriptional activation of the zygotic genome during embryonic development. A hallmark of MZT in mammals is its reliance on translation and the utilization of stored RNAs and proteins, rather than de novo transcription of genes, to sustain meiotic maturation and early development. Impaired maternal mRNA clearance at the onset of MZT prevents zygotic genome activation and causes early arrest of developing embryos. In this review, we discuss recent advances in our knowledge of the mechanisms whereby mRNA translation and degradation are controlled by cytoplasmic polyadenylation and deadenylation which set up the competence of maturing oocyte to accomplish MZT. The emphasis of this review is on the mouse as a model organism for mammals and BTG4 as a licensing factor of MZT under the translational control of the MAPK cascade.
41
Kiuchi, Tai, Tomoaki Nagai, Kazumasa Ohashi, and Kensaku Mizuno. "Measurements of spatiotemporal changes in G-actin concentration reveal its effect on stimulus-induced actin assembly and lamellipodium extension." Journal of Cell Biology 193, no. 2 (2011): 365–80. http://dx.doi.org/10.1083/jcb.201101035.
Full textAbstract:
To understand the intracellular role of G-actin concentration in stimulus-induced actin assembly and lamellipodium extension during cell migration, we developed a novel technique for quantifying spatiotemporal changes in G-actin concentration in live cells, consisting of sequential measurements of fluorescent decay after photoactivation (FDAP) of Dronpa-labeled actin. Cytoplasmic G-actin concentrations decreased by ∼40% immediately after cell stimulation and thereafter the cell area extended. The extent of stimulus-induced G-actin loss and cell extension correlated linearly with G-actin concentration in unstimulated cells, even at concentrations much higher than the critical concentration of actin filaments, indicating that cytoplasmic G-actin concentration is a critical parameter for determining the extent of stimulus-induced G-actin assembly and cell extension. Multipoint FDAP analysis revealed that G-actin concentration in lamellipodia was comparable to that in the cell body. We also assessed the cellular concentrations of free G-actin, profilin- and thymosin-β4–bound G-actin, and free barbed and pointed ends of actin filaments by model fitting of jasplakinolide-induced temporal changes in G-actin concentration.
42
Guillot, Marie-Noëlle. "Revisiting the methodological debate on interruptions." Pragmatics. Quarterly Publication of the International Pragmatics Association (IPrA) 15, no. 1 (2005): 25–47. http://dx.doi.org/10.1075/prag.15.1.02gui.
Full textAbstract:
This paper considers issues relating to the identification and categorisation of interruptive acts for cross- cultural study, as revealed by the conflicting methodological requirements of a medium-scale project involving contrastive analysis of confrontational native speaker and non-native speaker talk in French and English. The paper opens with a brief introduction to the project, followed by a review of issues from the conflicting ends of corpus annotation and Conversation Analysis, the main locus of information about, and research into, sequential aspects of talk and interruptive phenomena. It then uses two examples from the project data for native English and French respectively to reveal and discuss tensions between diverging requirements in the categorisation of interruptive acts. It shows that, while categorising interruptive phenomena inevitably entails a degree of arbitrariness - minimised in either very large corpora or small scale situated analysis -, medium-size data are peculiarly vulnerable to issues of empirical validity, but that their function and the options they create to derive critical findings from the tensions between approaches make them an important tool for research, notably cross-cultural research.
43
Frech, G. C., and L. Simpson. "Uridine insertion into preedited mRNA by a mitochondrial extract from Leishmania tarentolae: stereochemical evidence for the enzyme cascade model." Molecular and Cellular Biology 16, no. 8 (1996): 4584–89. http://dx.doi.org/10.1128/mcb.16.8.4584.
Full textAbstract:
An RNA editing-like internal uridine (U) incorporation activity (G. C. Frech, N. Bakalara, L Simpson, and A. M. Simpson, EMBO J. 14:178-187, 1995) and a 3'-terminal U addition activity (N. Bakalara, A. M. Simpson, and L. Simpson, J. Biol. Chem. 264:18679-18686, 1989) have been previously described by using a mitochondrial extract from Leishmania tarentolae. Chiral phosphorothioates were used to investigate the stereoconfiguration requirements and the stereochemical course of these nucleotidyl transfer reactions. The extract utilizes (SP)-alpha-S-UTP for both 3' and internal U incorporation into substrate RNA. The internal as well as the 3' incorporation of (SP)-alpha-S-UTP proceeds via inversion of the stereoconfiguration. Furthermore, internal U incorporation does not occur at sites containing thiophosphodiesters of the RP configuration. Our results are compatible with an enzyme cascade model for this in vitro U insertion activity involving sequential endonuclease and uridylyl transferase directly from UTP and RNA ligase steps and are incompatible with models involving the transfer of U residues from the 3' ends of guide RNAs.
44
Spahi, Enis, and D. Altilar. "ITU-PRP: Parallel and Distributed Computing Middleware for Java Developers." International Journal of Business & Technology 3, no. 1 (2014): 2–13. http://dx.doi.org/10.33107/ijbte.2014.3.1.01.
Full textAbstract:
ITU-PRP provides a Parallel Programming Framework for Java Developers on which they can adapt their sequential application code to operate on a distributed multi-host parallel environment. Developers would implement parallel models, such as Loop Parallelism, Divide and Conquer, Master-Slave and Fork-Join by the help of an API Library provided under framework. Produced parallel applications would be submitted to a middleware called Parallel Running Platform (PRP), on which parallel resources for parallel processing are being organized and performed. The middleware creates Task Plans (TP) according to application’s parallel model, assigns best available resource Hosts, in order to perform fast parallel processing. Task Plans will be created dynamically in real time according to resources actual utilization status or availability, instead of predefined/preconfigured task plans. ITU-PRP achieves better efficiency on parallel processing over big data sets and distributes divided base data to multiple hosts to be operated by Coarse-Grained parallelism. According to this model distributed parallel tasks would operate independently with minimal interaction until processing ends.
45
Wilson, J. W., and M. Arighi. "Comparative Effects of Fixation and Storage on Bone Tetracycline Fluorescence." Veterinary and Comparative Orthopaedics and Traumatology 10, no. 04 (1997): 200–204. http://dx.doi.org/10.1055/s-0038-1632596.
Full textAbstract:
SummaryAs an adjunct to an ongoing project, ends of longbones, including the growth plate, were collected from tetracycline labelled immature rabbits and calves. Samples were stored from a few days up to two months at room temperature, refrigerator temperature (+4°C), –20°C, or –70°C, and unfixed, formalin-fixed or alcohol-fixed. Qualitative and quantitative aspects of cut sections were evaluated. Freezing resulted in the least alteration. Fixed bone samples (alcohol or formalin) all progressively discoloured with increasing storage. Comparison between fresh, stored and differently fixed sections did not identify any change in the measured distance between labels; though the clarity of the labels was affected. Formalin fixation and storage did not result in mark degradation nor alteration of the labels.Tetracycline fluorescence, in labelled growth plates, was evaluated following storage from a few days up to two months at various temperatures and unfixed, formalin-fixed or alcohol-fixed. Neither the method of storage nor the fixative effected the measured distance between sequential labels in specimens. Fixed bone samples all discoloured with increasing storage. Previous literature alluded to problems with formalin fixation could not be substantiated in this study.
46
Zhang, Kaka, Margaret Ching-Lam Yeung, Sammual Yu-Lut Leung, and Vivian Wing-Wah Yam. "Living supramolecular polymerization achieved by collaborative assembly of platinum(II) complexes and block copolymers." Proceedings of the National Academy of Sciences 114, no. 45 (2017): 11844–49. http://dx.doi.org/10.1073/pnas.1712827114.
Full textAbstract:
An important feature of biological systems to achieve complexity and precision is the involvement of multiple components where each component plays its own role and collaborates with other components. Mimicking this, we report living supramolecular polymerization achieved by collaborative assembly of two structurally dissimilar components, that is, platinum(II) complexes and poly(ethylene glycol)-b-poly(acrylic acid) (PEG-b-PAA). The PAA blocks neutralize the charges of the platinum(II) complexes, with the noncovalent metal–metal and π–π interactions directing the longitudinal growth of the platinum(II) complexes into 1D crystalline nanostructures, and the PEG blocks inhibiting the transverse growth of the platinum(II) complexes and providing the whole system with excellent solubility. The ends of the 1D crystalline nanostructures have been found to be active during the assembly and remain active after the assembly. One-dimensional segmented nanostructures with heterojunctions have been produced by sequential growth of two types of platinum(II) complexes. The PAA blocks act as adapters at the heterojunctions for lattice matching between chemically and crystallographically different platinum(II) complexes, achieving heterojunctions with a lattice mismatch as large as 21%.
47
Epstein, H. F., D. M. Miller, I. Ortiz, and G. C. Berliner. "Myosin and paramyosin are organized about a newly identified core structure." Journal of Cell Biology 100, no. 3 (1985): 904–15. http://dx.doi.org/10.1083/jcb.100.3.904.
Full textAbstract:
Myosin isoforms A and B are differentially localized to the central and polar regions, respectively, of thick filaments in body wall muscle cells of Caenorhabditis elegans (Miller, D. M. III, I. Ortiz, G. C. Berliner, and H. F. Epstein, 1983, Cell, 34:477-490). Biochemical and electron microscope studies of KCl-dissociated filaments show that the myosin isoforms occupy a surface domain, paramyosin constitutes an intermediate domain, and a newly identified core structure exists. The diameters of the thick filaments vary significantly from 33.4 nm centrally to 14.0 nm near the ends. The latter value is comparable to the 15.2 nm diameter of the core structures. The internal density of the filament core appears solid medially and hollow at the poles. The differentiation of thick filament structure into supramolecular domains possessing specific substructures of characteristic stabilities suggests a sequential mode for thick filament assembly. In this model, the two myosin isoforms have distinct roles in assembly. The behavior of the myosins, including nucleation of assembly and determination of filament length, depend upon paramyosin and the core structure as well as their intrinsic molecular properties.
48
Brümmendorf, Tim H., Jaroslaw P. Maciejewski, Jennifer Mak, Neal S. Young, and Peter M. Lansdorp. "Telomere length in leukocyte subpopulations of patients with aplastic anemia." Blood 97, no. 4 (2001): 895–900. http://dx.doi.org/10.1182/blood.v97.4.895.
Full textAbstract:
Abstract In most human cells, the average length of telomere repeats at the ends of chromosomes provides indirect information about their mitotic history. To study the turnover of stem cells in patients with bone marrow failure syndromes, the telomere length in peripheral blood granulocytes and lymphocytes from patients with aplastic anemia (AA, n = 56) and hemolytic paroxysmal nocturnal hemoglobinuria (n = 6) was analyzed relative to age-matched controls by means of fluorescence in situ hybridization and flow cytometry. The telomere lengths in granulocytes from patients with AA were found to be significantly shorter than those in age-adjusted controls (P = .001). However, surprisingly, telomere length in granulocytes from AA patients who had recovered after immunosuppressive therapy did not differ significantly from controls, whereas untreated patients and nonresponders with persistent severe pancytopenia showed marked and significant telomere shortening. These results support extensive proliferation of hematopoietic stem cells in subgroups of AA patients. Because normal individuals show significant variation in telomere length, individual measurements in blood cells from AA patients may be of limited value. Whether sequential telomere length measurements can be used as a prognostic tool in this group of disorders remains to be clarified.
49
Gudanis, Dorota, Karolina Zielińska, Daniel Baranowski, Ryszard Kierzek, Piotr Kozłowski, and Zofia Gdaniec. "Impact of a Single Nucleotide Change or Non-Nucleoside Modifications in G-Rich Region on the Quadruplex–Duplex Hybrid Formation." Biomolecules 11, no. 8 (2021): 1236. http://dx.doi.org/10.3390/biom11081236.
Full textAbstract:
In this paper, a method to discriminate between two target RNA sequences that differ by one nucleotide only is presented. The method relies on the formation of alternative structures, i.e., quadruplex–duplex hybrid (QDH) and duplex with dangling ends (Dss), after hybridization of DNA or RNA G-rich oligonucleotides with target sequences containing 5′–GGGCUGG–3′ or 5′–GGGCGGG–3′ fragments. Using biophysical methods, we studied the effect of oligonucleotide types (DNA, RNA), non-nucleotide modifications (aliphatic linkers or abasic), and covalently attached G4 ligand on the ability of G-rich oligonucleotides to assemble a G-quadruplex motif. We demonstrated that all examined non-nucleotide modifications could mimic the external loops in the G-quadruplex domain of QDH structures without affecting their stability. Additionally, some modifications, in particular the presence of two abasic residues in the G-rich oligonucleotide, can induce the formation of non-canonical QDH instead of the Dss structure upon hybridization to a target sequence containing the GGGCUGG motif. Our results offer new insight into the sequential requirements for the formation of G-quadruplexes and provide important data on the effects of non-nucleotide modifications on G-quadruplex formation.
50
Ebshiana, Asma. "Response Tokens and Their Sequential Action in the Teacher Third Turn (Note 1) A Conversation Analysis Case Study in the EFL Classroom." International Journal of Linguistics 12, no. 2 (2020): 26. http://dx.doi.org/10.5296/ijl.v12i2.16585.
Full textAbstract:
In classroom settings, students` responses are regularly evaluated through the ubiquitous three-part sequence. It is through this pattern that teachers encourage student participation. Usually, the teacher uses response tokens such as “Okay”, Right” /” Alright”, “Mhm” “Oh”, in the third turn slot. These tokens are crucial and recurrent because they show where the teacher assesses the correctness or appropriateness of the students’ responses either end the sequence or begin a turn which ends the sequence. Moreover, such tokens have an impact on the sequence expansion and on the students’ participation. This article is a part of a large study examining the overall structure of the three-part sequence in data collected in an English pre-sessional programme (PSP) at the University of Huddersfield. The present article focuses on the analysis of naturally occurring data by using Conversation Analysis framework, henceforth (CA). A deep analysis is performed to examine how response tokens as evaluative responses are constructed sequentially in the third turn sequence as a closing action, whilst considering how some responses do not act as a closing sequence, since they elaborate and invite further talk. The results of response tokens have shown that they are greatly multifaceted. The analysis concluded that not all responses do the same function in the teacher’s third turn. Apart from confirming and acknowledging the student responses and maintaining listenership, some invite further contribution, others close and shift to another topic that designates closing the sequence, and some show a “change of state”. Their functions relate to their transitions, pauses and their intonation in the on-going sequence.