Double Helix of Phyllotaxis: Analysis of the Geometric Model of Plant Morphogenesis. By Boris Rozin. Irvine (California): BrownWalker Press. $39.95 (paper). xi + 171 p.; ill.; index. ISBN: 978-1-62734-748-8 (pb); 978-1-59942-604-4 (eb). 2020.

2021 ◽  
Vol 96 (2) ◽  
pp. 139-140
Author(s):  
Johan Gielis
Keyword(s):  
Double Helix ◽  
Geometric Model ◽  
Plant Morphogenesis

Protamine-DNA interaction

1978 ◽  
Vol 36 (2) ◽  
pp. 200-201
Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer
Keyword(s):  
Small Volume ◽  
Double Helix ◽  
Dna Interaction ◽  
Dark Field ◽  
Sperm Head ◽  
Nuclear Proteins ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Dna Double Helix ◽  
Positively Charged

Dark field electron microscopy has been used for the study of the structure of individual macromolecules with a resolution to at least the 5Å level. The use of this technique has been extended to the investigation of structure of interacting molecules, particularly the interaction between DNA and fish protamine, a class of basic nuclear proteins of molecular weight 4,000 daltons.Protamine, which is synthesized during spermatogenesis, binds to chromatin, displaces the somatic histones and wraps up the DNA to fit into the small volume of the sperm head. It has been proposed that protamine, existing as an extended polypeptide, winds around the minor groove of the DNA double helix, with protamine's positively-charged arginines lining up with the negatively-charged phosphates of DNA. However, viewing protamine as an extended protein is inconsistent with the results obtained in our laboratory.

Electron microscopic assays of restriction endonuclease cutting, exonuclease digestion, and hybridization

1984 ◽  
Vol 42 ◽  
pp. 686-687
Author(s):  
Mark Hannibal ◽  
Jacob Varkey ◽  
Michael Beer
Keyword(s):  
Electron Microscope ◽  
Low Temperature ◽  
Restriction Endonuclease ◽  
Double Helix ◽  
Test Material ◽  
Electron Microscopic ◽  
Exonuclease Iii ◽  
Dna Molecule ◽  
Linear Molecules ◽  
Exonuclease Digestion

Workman and Langmore have recently proposed a procedure for isolating particular chromatin fragments. The method requires restriction endonuclease cutting of the chromatin and a probe, their digestion with two exonucleases which leave complimentary single strand termini and low temperature hybridization of these. We here report simple electron microscopic monitoring of the four reactions involved.Our test material was ϕX-174 RF DNA which is cut once by restriction endonuclease Xho I. The conversion of circles to linear molecules was followed in Kleinschmidt spreads. Plate I shows a circular and a linear DNA molecule. The rate of cutting is shown in Figure 1.After completion of the endonuclease cutting, one portion of the DNA was treated with exonuclease III, an enzyme known to digest the 3' terminals of double helical DNA. Aliquots when examined in the electron microscope reveal a decreasing length of double helix and increasing bushes at the ends.

ALGEBRA OF PREDICATES AND RELATED GEOMETRIC MODELS CREATION IN REGARDS OF UNIFIED STATE EXAM IN INFORMATICS (RUSSIAN EGE)

2019 ◽  
pp. 40-47
Author(s):  
E. A. Mironchik
Keyword(s):  
Geometric Model ◽  
Main Idea ◽  
Formal Logic ◽  
High Complexity ◽  
Geometric Models ◽  
Complexity Problem ◽  
Logical Expression ◽  
State Examination

The article discusses the method of solving the task 18 on the Unified State Examination in Informatics (Russian EGE). The main idea of the method is to write the conditions of the problem utilizing the language of formal logic, using elementary predicates. According to the laws of logic the resulting complex logical expression would be transformed into an expression, according to which a geometric model is supposed to be constructed which allows to obtain an answer. The described algorithm does allow high complexity problem to be converted into a simple one.

DNA Inspirited Rational Construction of Nonconventional Luminophores with Efficient and Color-Tunable Afterglow

2020 ◽  
Author(s):  
Yunzhong Wang ◽  
Saixing Tang ◽  
Yating Wen ◽  
Shuyuan Zheng ◽  
Bing Yang ◽  
...  
Keyword(s):  
Rational Design ◽  
Room Temperature ◽  
Double Helix ◽  
Mechanical Grinding ◽  
Room Temperature Phosphorescence ◽  
Color Tunable ◽  
Potential Applications ◽  
Rational Construction ◽  
Double Helix Structure ◽  
Made In

<div>Persistent room-temperature phosphorescence (p-RTP) from pure organics is attractive </div><div>due to its fundamental importance and potential applications in molecular imaging, </div><div>sensing, encryption, anticounterfeiting, etc.1-4 Recently, efforts have been also made in </div><div>obtaining color-tunable p-RTP in aromatic phosphors5 and nonconjugated polymers6,7. </div><div>The origin of color-tunable p-RTP and the rational design of such luminogens, </div><div>particularly those with explicit structure and molecular packing, remain challenging. </div><div>Noteworthily, nonconventional luminophores without significant conjugations generally </div><div>possess excitation-dependent photoluminescence (PL) because of the coexistence of </div><div>diverse clustered chromophores6,8, which strongly implicates the possibility to achieve </div><div>color-tunable p-RTP from their molecular crystals assisted by effective intermolecular </div><div>interactions. Here, inspirited by the highly stable double-helix structure and multiple </div><div>hydrogen bonds in DNA, we reported a series of nonconventional luminophores based on </div><div>hydantoin (HA), which demonstrate excitation-dependent PL and color-tunable p-RTP </div><div>from sky-blue to yellowish-green, accompanying unprecedentedly high PL and p-RTP </div><div>efficiencies of up to 87.5% and 21.8%, respectively. Meanwhile, the p-RTP emissions are </div><div>resistant to vigorous mechanical grinding, with lifetimes of up to 1.74 s. Such robust, </div><div>color-tunable and highly efficient p-RTP render the luminophores promising for varying </div><div>applications. These findings provide mechanism insights into the origin of color-tunable </div><div>p-RTP, and surely advance the exploitation of efficient nonconventional luminophores.</div>

The two greatest discoveries of two centuries - the nuclein and the double helix of DNA

Biomics ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 259-265
Author(s):  
G.A. Gerashchenkov ◽  
R.R. Garafutdinov ◽  
An.Kh. Baymiev ◽  
B.R Kuluev ◽  
Al.Kh. Baymiev ◽  
...  
Keyword(s):  
Double Helix

Modeling the Snow Deposit Process on the Highways in the Flowvision Software

2020 ◽  
pp. 72-83
Author(s):  
Т. В. Самодурова ◽  
О. В. Гладышева ◽  
Н. Ю. Алимова ◽  
Е. А. Бончева
Keyword(s):  
Hydrodynamic Model ◽  
Geometric Model ◽  
Information Resources ◽  
Road Maintenance ◽  
Snow Removal ◽  
Experimental Section ◽  
Deposit Modeling ◽  
Winter Road ◽  
Highway Embankment ◽  
Winter Road Maintenance

Постановка задачи. Рассмотрена задача моделирования отложения снега во время метелей на автомагистралях с барьерными ограждениями в программе FlowVision . Результаты. В качестве опытного участка рассмотрен участок автомагистрали, проходящий в насыпи. Создана геометрическая модель участка автомагистрали. Обоснованы информационные ресурсы для создания гидродинамической модели обтекания насыпи автомагистрали с барьерными ограждениями снеговетровым потоком во время метелей. Проведено моделирование процесса снегонакопления на опытном участке с использованием программного комплекса FlowVision во время метелей с различными параметрами. Выводы. Сделан вывод о возможности применения программного комплекса FlowVision для совершенствования методики назначения снегозащитных устройств и определения параметров снегоочистки при зимнем содержании автомобильных дорог. Statement of the problem. The problems of snow deposit modeling on the highways with crash barriers during blizzards in the FlowVision was discussed. Results. The highway section passing in the embankment as an experimental section has been considered. The geometric model of the highway section was created. The information resources for designing a hydrodynamic model of a snowflow stream of highway embankment with barriers during blizzard were identified. The modeling of the snow deposit process in the experimental section using the FlowVision software during blizzards with different parameters was carried out. Conclusions. It was concluded that it is possible to use the FlowVision software to improve the methodology for snow protection designing and determining snow removal parameters for winter road maintenance.

Sign in / Sign up

Export Citation Format

Share Document