Double-stranded DNA organization in bacteriophage heads: an alternative toroid-based model

Studies of the organization of double-stranded DNA within bacteriophage heads during the past four decades have produced a wealth of data. However, despite the presentation of numerous models, the true organization of DNA within phage heads remains unresolved. The observations of toroidal DNA structures in electron micrographs of phage lysates have long been cited as support for the organization of DNA in a spool-like fashion. This particular model, like all other models, has not been found to be consistent will all available data. Recently we proposed that DNA within toroidal condensates produced in vitro is organized in a manner significantly different from that suggested by the spool model. This new toroid model has allowed the development of an alternative model for DNA organization within bacteriophage heads that is consistent with a wide range of biophysical data. Here we propose that bacteriophage DNA is packaged in a toroid that is folded into a highly compact structure

ANALISIS MATERI YANG SULIT PADA MATA KULIAH STRATEGI BELAJAR MENGAJAR (SBM) DI PROGRAM STUDI PENDIDIKAN KIMIA FKIP UNSYIAH TAHUN AKADEMIK 2015/2016

ABSTRAK Kata Kunci: Materi yang Sulit, Strategi Belajar Mengajar (SBM) Telah dilakukan penelitian tentang analisis materi yang sulit pada mata kuliah Strategi Belajar Mengajar (SBM) di Program Studi Pendidikan Kimia. Tujuan dari penelitian ini untuk mengetahui (1) materi yang sulit dipahami oleh mahasiswa (2) penyebab kesulitan mahasiswa dalam memahami materi pada mata kuliah SBM di Program Studi Pendidikan Kimia. Tehnik pengumpulan data yaitu dengan menggunakan instrumen berupa angket. Jenis penelitian adalah deskriptif kualitatif. Subjek dalam penelitian ini adalah 47 orang mahasiswa dari Program Studi Pendidikan Kimia Tahun Akademik 2015/2016.. Analisis data dalam penelitian ini menggunakan rumus persentase. Hasil persentase kesulitan yang diperoleh berdasarkan analisis data terhadap angket tanggapan mahasiswa untuk masing-masing materi yaitu (1) hakikat SBM 33,33%; (2) teori belajar 46,81%; (3) tahapan mengajar 43,25%; (4) keterampilan dasar mengajar 63,83%; (5) model, pendekatan dan metode pembelajaran 70,21%; (6) tahapan mengajar 43,25%; (7) simulasi pembelajaran 42,55%; (8) sumber belajar 37,23%; (9) pengelolaan kelas 45,74%; (10) remedial dan pengayaan 26,6%. Kesulitan-kesulitan yang dihadapi oleh mahasiswa pada tiap materi SBM berdasarkan persentase yang terbesar (1) mahasiswa sulit menyesuaikan antara model, pendekatan dan ketrampilan mengajar (2) mengidentifikasi kesesuaian antara materi dengan teori belajar, (3) mahasiswa masih bingung mengaplikasikan ketrampilan mengajar, (4) menyusun langkah-langkah yang sesuai dengan model yang dipilih. Hal ini disebabkan (1) dosen sedikit memberikan kesempatan kepada mahasiswa untuk melakukan simulasi pembelajaran, (2) contoh ketrampilan dasar mengajar yang diberikan masih sedikit, (3) penjelasan tentang materi masih bersifat universal, (4) dosen tidak mengaplikasikan secara langsung di dalam proses pembelajaran

Innovation budgeting over the business cycle and innovation performance

The global economic crisis of 2008/2009 hit many firms hard. Faced with rapidly declining sales and highly uncertain economic prospects, firms had to cut costs and reconsider their business strategies. With respect to innovation, cost cutting often means to stop or underresource innovation projects which may harm a firm’s long-term competitiveness. Firms may therefore refrain from reducing innovation budgets during crises but rather deliberately allocate more resources to innovation activities in order to update their product portfolio for the following recovery. Our analysis examines the effects of changes in innovation budgets during the most recent economic crisis on firms’ post-crisis innovation performance. Based on firm-level panel data from the German Innovation Survey covering the period 2006 to 2012, we find a positive effect of crisis adjustment. Raising the ratio of innovation expenditure to sales does increase subsequent sales of market novelties, but not of product imitations. Our findings are dependent upon the way business cycle effects are measured, however. While the results hold for macroeconomic business cycle indicators (change in real GDP), they do not for demand changes in a firm’s primary sales market. This may imply that lower opportunity costs of innovation during an economic crisis are transferred into higher post-crisis new product sales by firms in markets less strongly affected by the crisis

Major G-Quadruplex Form of HIV-1 LTR Reveals a (3 + 1) Folding Topology Containing a Stem-Loop

Nucleic acids can form noncanonical four-stranded structures called G-quadruplexes. G-quadruplex-forming sequences are found in several genomes including human and viruses. Previous studies showed that the G-rich sequence located in the U3 promoter region of the HIV-1 long terminal repeat (LTR) folds into a set of dynamically interchangeable G-quadruplex structures. G-quadruplexes formed in the LTR could act as silencer elements to regulate viral transcription. Stabilization of LTR G-quadruplexes by G-quadruplex-specific ligands resulted in decreased viral production, suggesting the possibility of targeting viral G-quadruplex structures for antiviral purposes. Among all the G-quadruplexes formed in the LTR sequence, LTR-III was shown to be the major G-quadruplex conformation in vitro. Here we report the NMR structure of LTR-III in K+ solution, revealing the formation of a unique quadruplex-duplex hybrid consisting of a three-layer (3 + 1) G-quadruplex scaffold, a 12-nt diagonal loop containing a conserved duplex-stem, a 3-nt lateral loop, a 1-nt propeller loop, and a V-shaped loop. Our structure showed several distinct features including a quadruplex-duplex junction, representing an attractive motif for drug targeting. The structure solved in this study may be used as a promising target to selectively impair the viral cycle

Health and recreation center design with the study of concrete strength

У дипломній роботі розроблено проект профілакторію. Запропоновано об’ємно-планувальні та архітектурно-конструктивні рішення. Виконано розрахунок основних несучих конструкцій за двома групами граничних станів. Розроблено технологічні карти, календарний графік, будівельний генеральний план. Встановлено вплив на експлуатаційну стійкість та довговічність рухомості суміші, активності цементу, пористості. Визначено доцільність використання коефіцієнту конструктивної якості для експрес оцінки бетону. З’ясовано ряд технологічних прийомів, що збільшують міцність бетонів. Розроблено заходи по охороні праці, цивільному захисту населення при пожежі та зменшенню негативного впливу будівництва профілакторію на навколишнє середовище.Гудь М.І. Проект профілакторію з дослідженням міцності бетону. – Дипломна робота на здобуття освітнього ступеня «магістр» за спеціальністю 192 «Будівництво та цивільна інженерія». Тернопільський національний технічний університет імені Івана Пулюя, м. Тернопіль, 2018 р

Multiple prebiotic metals mediate translation.

Today, Mg2+ is an essential cofactor with diverse structural and functional roles in life's oldest macromolecular machine, the translation system. We tested whether ancient Earth conditions (low O2, high Fe2+, and high Mn2+) can revert the ribosome to a functional ancestral state. First, SHAPE (selective 2'-hydroxyl acylation analyzed by primer extension) was used to compare the effect of Mg2+, Fe2+, and Mn2+ on the tertiary structure of rRNA. Then, we used in vitro translation reactions to test whether Fe2+ or Mn2+ could mediate protein production, and quantified ribosomal metal content. We found that (i) Mg2+, Fe2+, and Mn2+ had strikingly similar effects on rRNA folding; (ii) Fe2+ and Mn2+ can replace Mg2+ as the dominant divalent cation during translation of mRNA to functional protein; and (iii) Fe and Mn associate extensively with the ribosome. Given that the translation system originated and matured when Fe2+ and Mn2+ were abundant, these findings suggest that Fe2+ and Mn2+ played a role in early ribosomal evolution