Probing transient protein-mediated DNA linkages using nanoconfinement     

Maedeh Roushan  Parminder Kaur  Alena Karpusenko  Preston J. Countryman  Carlos P. Ortiz  Shuang Fang Lim  Hong Wang  Robert Riehn 《Biomicrofluidics》2014,8(3)

We present an analytic technique for probing protein-catalyzed transient DNA loops that is based on nanofluidic channels. In these nanochannels, DNA is forced in a linear configuration that makes loops appear as folds whose size can easily be quantified. Using this technique, we study the interaction between T4 DNA ligase and DNA. We find that T4 DNA ligase binding changes the physical characteristics of the DNA polymer, in particular persistence length and effective width. We find that the rate of DNA fold unrolling is significantly reduced when T4 DNA ligase and ATP are applied to bare DNA. Together with evidence of T4 DNA ligase bridging two different segments of DNA based on AFM imaging, we thus conclude that ligase can transiently stabilize folded DNA configurations by coordinating genetically distant DNA stretches.  相似文献   

Understanding the development of technology-intensive suppliers in resource-based developing economies     

Carlos Torres-Fuchslocher 《Research Policy》2010,39(2):268-277

The development of local technology-intensive suppliers (t-suppliers) may contribute to both reinforcing the industrial base and supporting the competitiveness of primary production in developing countries. This article explores the role of t-suppliers in natural resource-based economies and outlines a theoretical framework for the analysis of the factors which foster or constrain their development and defines areas for an effective promotion. The proposed model of analysis distinguishes between factors influencing the development of t-suppliers on the level of the main industry, the level of supplier firms or firm-level and the level of external determinants with special reference to industrial policy factors.  相似文献   

Effective force and economy of triathletes and cyclists   总被引：1，自引：0，他引：1  

Candotti CT  Ribeiro J  Soares DP  De Oliveira AR  Loss JF  Guimarães AC 《Sports biomechanics / International Society of Biomechanics in Sports》2007,6(1):31-43

The effective force applied on the crank, the index of pedalling effectiveness, and the economy of movement at 60, 75, 90, and 105 rev/min cadences were examined in nine cyclists and eight triathletes. Tests were performed on two days. Maximal oxygen uptake was measured and the second ventilatory threshold was estimated on day 1 using a stationary bicycle. On day 2, the four different cadences were tested at about 5% below the second ventilatory threshold. A strain gauge instrumented clip-less pedal mounted on the bicycle enabled us to measure the normal and tangential forces exerted on the pedal, while the pedal and crank angles were monitored with the aid of a video system. Based on this information, the effective force and the index of pedalling effectiveness were calculated. Cyclists produced significantly more effective force and a higher index of pedalling effectiveness at 60 and 75 rev/min and were significantly more economic at all cadences than triathletes. The significant and positive correlation between effective force and economy at all cadences suggests that improvement of the effective force would reflect on economy.  相似文献   

An Activist Approach to Sport Meets Youth From Socially Vulnerable Backgrounds: Possible Learning Aspirations     

Carla Luguetti  Kimberly L. Oliver  Luiz Eduardo Pinto Basto Tourinho Dantas  David Kirk 《Research quarterly for exercise and sport》2017,88(1):60-71

Purpose: This study was a 2-phase activist research project aimed at co-creating a prototype pedagogical model for working with youth from socially vulnerable backgrounds in a sport context. This article addresses the learning aspirations (learning outcomes) that emerged when we created spaces for youth to develop strategies to manage the risks they face in their community. Method: This study took place in a socially and economically disadvantaged neighborhood in a Brazilian city where we worked with a group of 17 boys aged 13 to 15 years old, 4 coaches, a pedagogic coordinator, and a social worker. During a 6-month period, we collected multiple sources of data including field journal entries/observations (38) and audio records of youth work sessions (18), coaches' work sessions (16), combined coaches and youth work sessions (3), and meetings between the lead and the 2nd author for debriefing and planning sessions (36). Results: By using an activist approach, 4 learning aspirations emerged: becoming responsible/committed, learning from mistakes, valuing each other's knowledge, and communicating with others. Conclusion: Findings suggest there is a need for more sports programs that start from young people's concrete needs and life situations and look to create places for youth to see alternative possibilities and take action.  相似文献   

Effect of the level of effort during resistance training on intraocular pressure     

Jesús Vera  Beatríz Redondo  Alejandro Torrejón  Carlos Gustavo De Moraes  Amador García-Ramos 《European Journal of Sport Science》2019,19(3):394-401

Background: We aimed to evaluate the influence of the level of effort during four basic resistance exercises leading to muscular failure on intraocular pressure (IOP) and ocular perfusion (OPP), as well as the role of exercise type and sex. Methods: Twenty-five young adults (12 women) performed 10 repetitions against their 10-RM (repetition maximum) load in the squat, military press, biceps curl and calf raise exercises. IOP was measured before, during and after exercise, whereas OPP was indirectly assessed before and after each exercise. Results: There was a progressive IOP rise during exercise (p?η²?=?0.531), which was dependent on exercise type (p?=?0.020, η²?=?0.125). The squat exercise induced higher IOP increments in comparison to the other exercises (corrected p-values?p-values?=?0.012 and 0.002). OPP exhibited a significant reduction when leading to muscular failure (p?=?0.001, η²?=?0.364), being statistically significant for the squat and military press exercises (corrected p-values?=?0.037 and 0.047). No effect of sex was found for IOP and OPP (p?>?0.05). Conclusions: A single set of resistance training leading to muscular failure causes an instantaneous and progressive IOP rise in healthy young individuals. These IOP rises depend on exercise type (squat?>?military press?=?biceps curl?>?calf raise), but not on participant´s sex. OPP diminished as a consequence of performing resistance training exercise, being statistically significant for the squat and military press exercises. Future studies should include glaucoma patients aiming to corroborate the generalizability of our findings.  相似文献   

Combined training,FNDC5/irisin levels and metabolic markers in obese men: A randomised controlled trial     

Ivan Luiz Padilha Bonfante  Mara Patrícia Traina Chacon-Mikahil  Diego Trevisan Brunelli  Arthur Fernandes Gáspari  Renata Garbellini Duft  Wendell Arhur Lopes 《European Journal of Sport Science》2017,17(5):629-637

The effects of training on FNDC5/irisin and its association with fitness and metabolic marker improvements induced by training have been poorly investigated in humans. Thus, the present study assessed the effects of combined training (CT) on FNDC5/irisin levels, metabolic markers and fitness adaptations in obese men. Middle-age obese men (age 49.13?±?5.75, body mass index (BMI) 30.86?±?1.63) were randomly distributed in the CT group (n?=?12) and control group (CG n?=?10). The CT consisted of strength followed by aerobic training, 3 times/week, for 24 weeks. Body composition, physical fitness, plasma FNDC5/irisin, biochemical markers and metabolic scores/index were evaluated. CT maintained FNDC5/irisin levels (µg/mL) (pre: 4.15?±?0.32, post: 4.21?±?0.32; p?=?.96) and improved body composition, metabolic and physical fitness markers. In the CG, decreased FNDC5/irisin (µg/mL) (pre: 4.36?±?0.23, post: 3.57?±?0.94; p?=?.01) and reduced strength (supine exercise/kg) (pre: 71?±?14.7, post: 60.1?±?14.05; p?<?.01) were observed, along with a trend to increase HOMA-IR (pre: 2.63?±?1.11, post: 3.14?±?1.27; p?=?.07) and other indicators of metabolic deterioration. An inverse correlation was found between the change (Δ%) in levels of FNDC5/irisin and Δ% glucose, Δ% total cholesterol, Δ% triglycerides and Δ% waist circumference, in addition to a positive relation with Δ% muscle strength. In conclusion, CT maintained FNDC5/irisin levels and provided metabolic and fitness benefits. The correlation between FNDC5/irisin changes and metabolic parameters, as well as the FNDC5/irisin reduction associated with fitness and metabolic worsening in the CG, suggests a relationship between FNDC5/irisin and a healthy metabolic status in humans.  相似文献   

Effects of different strength training frequencies during reduced training period on strength and muscle cross-sectional area     

Lucas Duarte Tavares  Eduardo Oliveira de Souza  Carlos Ugrinowitsch  Gilberto Candido Laurentino  Hamilton Roschel  André Yui Aihara 《European Journal of Sport Science》2017,17(6):665-672

This study investigated the effects of different reduced strength training (RST) frequencies on half-squat 1 RM and quadriceps cross-sectional area (QCSA). Thirty-three untrained males (24.7?±?3.9 years; 1.73?±?0.08?m; 74.6?±?8.4?kg) underwent a 16-week experimental period (i.e. eight weeks of strength training [ST] followed by additional eight weeks of RST). During the ST period, the participants performed 3–4 sets of 6–12 RM, three sessions/week in half-squat and knee extension exercises. Following ST, the participants were randomly allocated to one of three groups: reduced strength training with one (RST1) or two sessions per week (RST2), and ceased training (CT). Both RST1 and RST2 groups had their training frequency and total training volume-load (i.e. RST1?=?50.3% and RST2?=?57.1%) reduced, while the CT group stopped training completely. Half-squat 1 RM (RST1?=?27.9%; RST2?=?26.7%; and CT?=?28.4%) and QCSA (RST1?=?6.1%; RST2?=?6.9%; and CT?=?5.8%) increased significantly (p?<?.05) in all groups after eight weeks of ST. No significant changes were observed in 1 RM and QCSA for RST1 and RST2 groups after the RST period, while the CT group demonstrated a decrease in half-squat 1 RM (22.6%) and QCSA (5.4%) when compared to the ST period (p?<?.05). In conclusion, different RST frequencies applied were able to maintain muscle mass and strength performance obtained over the regular ST period. Thus, it appears that RST frequency does not affect the maintenance of muscle mass and strength in untrained males, as long as volume-load is equated between frequencies.  相似文献   

Swelling damage in clay-rich sandstones used in the church of San Mateo in Tarifa (Spain)   总被引：1，自引：0，他引：1  

Eduardo Sebastin  Giuseppe Cultrone  David Benavente  Lucia Linares Fernandez  Kerstin Elert  Carlos Rodriguez-Navarro 《Journal of Cultural Heritage》2008,9(1):66-76

This study shows that the sandstone used in the construction of the Church of San Mateo in Tarifa (Cádiz, Spain) is highly sensitive to processes of decay because of a combination of factors that are intrinsic and extrinsic to the material. The mineralogy, texture and porous system of the sandstone and the proximity of the church to the sea all play a part in these processes. X-ray diffraction reveals that there are interstratified chlorite/smectite clays among the minerals that make up the rock. These mixed layer clays have been shown to undergo hydric expansion. This phenomenon may be accompanied and augmented by the presence of NaCl which acts as an electrolyte in osmotic swelling processes. Two varieties of sandstone were used in the construction of the church, namely grey sandstone and brown sandstone. The latter is more porous and undergoes greater hydric expansion, showing a higher degree of deterioration. Ultrasound analysis has demonstrated that both varieties are anisotropic because they contain bedding planes and are affected by the preferred orientation of the phyllosilicates in the rock. The anisotropic nature of these stones was confirmed by capillary suction tests. The capillary front reaches a relatively low height which means that when water is absorbed, the anisotropic textural properties combined with the presence of chlorite–smectite mixed layers in the sandstone result in mechanical (shear) stress between the first few centimetres of the wet stone and the dry area behind. The latter effect favours the development of flakes, so causing the decay of the ornamental stone and the church façade.  相似文献   

Improving OER descriptions to enhance their availability,reuse, and enrichment     

Herrera-Cubides  Jhon Francined  Gaona-Garc&#;a  Paulo Alonso  Montenegro-Mar&#;n  Carlos Enrique  S&#;nchez-Alonso  Salvador 《Education and Information Technologies》2022,27(2):1811-1839

Education and Information Technologies - Nowadays, information and communication technologies (ICTs) and virtual training have increased the use of educational resources. This growth use has...  相似文献   

Using sensemaking as a lens to assess student learning on corporate social responsibility and sustainability     

Lutz Preuss  Isabel Fischer  John M. Luiz 《Higher Education Quarterly》2023,77(4):676-692

Prior literature suggests that teaching corporate social responsibility (CSR) and sustainability has led to little development of students' reflexive engagement with the challenges of sustainable development. To shed light on this criticism, we apply sensemaking—as entailing the three stages of scanning for information, interpreting it and identifying alternatives of action—to CSR/sustainability education. Analysing cognitive maps of CSR, drawn by undergraduate finalists from a UK business school, we find that students are able to produce complex cognitive maps in terms of scanning for information; however, cognitive bottlenecks occur at the second and third stages of sensemaking. A key pedagogical challenge is, therefore, to support students in moving beyond scanning towards developing meaning and acting on that basis. By introducing a sensemaking lens, we add to a deeper understanding of the complexities associated with CSR education as it aids (or impedes) critical engagement and action.  相似文献