Study of factors controlling the photoprotection capacity of the thylakoid membrane

PhDPlants require light for the process of photosynthesis, but excess of light absorption can cause photooxidative damage. To avoid this damage, plants have evolved a photoprotective mechanism to dissipate excess light energy as heat in a process called nonphotochemical quenching (NPQ). This regulatory mechanism of light harvesting involves both pigment and protein constituents of antenna complexes. Two xanthophylls, lutein and zeaxanthin, have been implicated to contribute to the rapidly relaxing qE component of NPQ, acting as quenchers of the chlorophyll excitation energy. To determine the molecular mechanism of NPQ and role of these xanthophylls in it, the kinetics of qE and qE-related conformational changes were measured in Arabidopsis thaliana mutant plants with altered xanthophyll contents. The effect of xanthophyll composition on the chlorophyll excited state lifetime was also compared - in leaves and native isolated antenna complexes. The data reveal that the replacement of lutein by either zeaxanthin or violaxanthin in the internal binding sites of the antenna complexes affects the qE kinetics and amplitude as well as the absolute chlorophyll fluorescence lifetime. This demonstrates the role of lutein in maintaining the efficient photoprotective state. The PsbS protein of photosystem II has also been demonstrated to play a significant role in controlling the qE component of NPQ. Thereby, enhancement of PsbS and resultant increase in qE and qE-related conformational changes was achieved in Arabidopsis by physiological and genetic means in the absence of zeaxanthin. This helps to dissect the relationship between zeaxanthin and PsbS in NPQ, suggesting both as independent entities. The results support allosteric role of zeaxanthin and not as the direct quencher alone or in combination with the PsbS in the process, whilst the role of PsbS is suggested as kinetic modulator of conformational change which results in NPQ.Queen Mary of London Postgraduate Research StudentshipQueen Mary university of London Postgraduate Research Studentshi

The effect of different road load implementation strategies on fuel economy of USPS step vans

West Virginia University (WVU) is continuously improving and updating their testing quality, procedures and goals. As tests are conducted on the Transportable Heavy Duty Vehicle Emissions Testing Laboratory (THDVETL), real world implementation is crucial in order to compare and contrast vehicles within fleets, use of exhaust aftertreatment devices and hybridized vehicles. WVU implements road loads on the chassis dynamometer using a method described in 40 CFR §86.1229-85. The proposed method requires three variables from the vehicle: maximum height, maximum width and vehicle weight. The issue with this method arises due to the fact that it does not cover a wide range of heavy duty vehicle physical characteristics.;An alternative form of implementing road loads is to conduct on-road coastdowns and use regression analysis to determine the vehicles? characteristics such as coefficient of drag and coefficient of rolling resistance. The coastdown procedure involves driving a vehicle to a speed and setting the transmission to neutral and letting the vehicle slow until it reaches a complete stop. Since there is no power being transmitted to the wheels, regression analysis of the speed versus time can be used to determine physical characteristics of the vehicle. Using the road load equation, which consists of four components (hill climbing load, inertial load, aerodynamic resistance and rolling resistance) one can implement real world power demand on the chassis dynamometer.;20 tests were conducted using the FTP-75 test schedule and two USPS step vans with one being a hybridized version. Four test configurations were used for this study, loaded and unloaded for each of the two vehicles. The empirical method of road load implementation proved to be more suitable for this USPS step van compared to the theoretical method. The theoretical method assumes that the vehicle\u27s aerodynamic drag is 0.735 compared to the empirical method\u27s equates to 0.669. WVU uses eddy current dynamometers as a power absorption system to simulate aerodynamic drag and rolling resistance. The power absorption setting for the theoretical model was higher than that of empirical model, as expected. A noticeable fuel economy comparison for both vehicles arose due to more aggressive setting from the theoretical method compared to that of empirical method. The hybrid vehicle showed a 34.4% better fuel economy compared to the baseline vehicle using the empirical method. The theoretical method showed an improvement of 24.8% from the hybrid vehicle compared to the baseline vehicle. Comparing the amount of work done for each vehicle during the test cycles, the theoretical method showed a 2.29% difference between the two vehicles compared to the empirical method of 15.0%. This study proves that the theoretical model forces the hybrid vehicle to operate at higher loads where the full potential of the system is not used

Microenterprises Performance under Consulting Services and Clustering: A Study of Egypt and Turkey

Besides access to credit, the presence of consulting services and formation of clusters play an important role in microenterprises performance. I analyze the impact of consulting services and clustering on microenterprises\u27 profits and assets in Egypt and Turkey, using a unique dataset on medium and small enterprises in both countries. I find that use of consulting services, and clustering, positively affect the profits and assets of microenterprises

Effectiveness of bagasse ash for performance improvement of asphalt concrete pavements

AbstractThe performance of asphalt concrete pavements (ACP) is greatly related to the rate of rutting. Stone dust is mostly used as a filler in ACP. Bagasse ash being cementitious in nature, and costless waste can also be used as a filler. The overall aim is to select a suitable filler for better performance of asphalt concrete pavements. The effectiveness of locally available bagasse ash is examined as a filler for asphalt concrete in terms of its effect on job mix formula, stability, rutting depth, the rise in temperature, and cost of asphalt concrete. All tests are performed as per AASHTO standards. The bagasse ash asphalt concrete showed a reduction in rutting depth, temperature rise, and cost as compared to that of the stone dust asphalt concrete without disturbing the job mix formula. Hence, bagasse ash can be helpful for the performance enhancement of asphalt concrete pavements

Surgical management of subclavian and proximal axillary artery injuries

Subclavian and proximal axillary arterial injuries are rare and difficult to manage. Eight patients were managed from January 2008 to December 2018 at The Aga Khan University Hospital, Karachi, Pakistan with mean age of 36.13 ± 14.48 years. All patients had penetrating injuries, from gunshot in 5 (62.5%), bomb blast in 2 (25%), and stab wound in 1 (12.5%) case. Six (75%) patients presented in haemodynamically stable condition. The mean time between the injury and patient presentation was 28 ± 8.39 hours. The injuries were approached via supraclavicular incision in 3 (37.5%) patients, infraclavicular incisions in 2 (25%) patients and median sternotomy in 2 (25%) patients. Three (37.5%) patients had false aneurysm, while 5 (62.5%) had transected artery. Primary repair was performed in 2 (25%) cases, while 6 (75%) patients were treated with interposition graft with polytetrafluoroethylene (PTFE). All patients have salvaged limbs with good functional outcomes

PENGEMBANGAN PENUNTUN PRAKTIKUM FISIKA SMA KELAS X SEMESTER GANJIL

ABSTRAK Penelitian pengembangan ini bertujuan untuk menghasilkan produk penuntun praktikum fisika SMA Kelas X Semester Ganjil dan mengetahui kelayakan penuntun praktikum sebagai panduan dalam proses pembelajaran praktikum satu semester ganjil. Tahapan penelitian pengembangan ADDIE dimulai dari tahap Analyze, Design, Development, Implementation, Evaluations. Subjek penelitian ini adalah peserta didik kelas X SMA Negeri 1 Bandar Sribhawono Lampung Timur, MA Sriwijaya Lampung Timur, dan MA Bandar Agung Lampung Timur Tahun Pelajaran 2022/2023. Data penelitian ini diperoleh menggunakan lembar angket validasi ahli dan lembar angket respon pendidik dan peserta didik. Hasil analisis data kevalidan dan kemenarikan penuntun praktikum fisika kelas X semester ganjil yang dikembangkan termasuk dalam kategori valid dan menarik. Dengan demikian dapat disimpulkan bahwa praktikum fisika kelas X semester ganjil valid dan menarik untuk digunakan dalam praktikum fisika peserta didik. Kata kunci: Penuntun praktikum, fisika. iii ABSTRACT This development research aims to produce physics practicum guide products for SMA Class X Odd Semester and determine the feasibility of practicum guides as a guide in the learning process for one odd semester practicum. The stages of ADDIE development research start from the Analyze, Design, Development, Implementation, Evaluation stages. The subjects of this study were students in class X SMA Negeri 1 Bandar Sribhawono East Lampung, MA Sriwijaya East Lampung, and MA Bandar Agung East Lampung for the 2022/2023 academic year. The research data were obtained using expert validation questionnaire sheets and teacher and student response questionnaire sheets. The results of the data analysis on the validity and attractiveness of the physics practicum guide for class X in the odd semester that were developed were included in the valid and interesting category. Thus it can be concluded that the odd semester physics practicum for class X is valid and interesting to use in students' physics practicum. Keywords: Practicum guide, physics

Toothpastes: A review of types, ingredients and possible side effects

Introduction: Toothpastes are one of the most widely sold and used dental products, with their use as one of the most popular oral hygiene behaviors in developed countries. A large variety of toothpastes are available on the market for different purpose, making it difficult for patients to select appropriate ones and for clinicians to prescribe the most useful one. This review provides details on the ingredients of toothpastes and their clinical use, trying to assist oral care practitioners in recommending appropriate toothpastes to their patients based on their individual needs. Review Report: This review was carried out by running a search in various databases, including references books, PubMed, ISI Web of Science and Google search engine from 1973 to 2011 using the terms toothpastes, Periodontics and dental plaque. Results: There are large varieties of toothpastes for different purposes: caries prevention, gingivitis prevention, anti-calculus, dentin hypersensitivity prevention and for tooth whitening, with a wide range of active and non-active ingredients, including abrasives, humectants, preservatives, thickening or binding agents, detergents, flavoring agents and therapeutic agents as fluoride, bacteriostatics, pyrophosphates, tooth desensitizing agents etc. Some studies have evaluated the effects, advantages and disadvantages of each ingredient. Conclusion: It is absolutely necessary for dental practitioners to have a sound knowledge of chemical compositions and ingredients of toothpastes to be able to assist their patients in selecting appropriate and efficacious toothpastes

Methyl 2-(1,1,3-trioxo-2,3-dihydro-1,2-benzothia­zol-2-yl)acetate: a monoclinic polymorph

In the title compound, C10H9NO5S, the fused ring system and the planar (r.m.s. deviation = 0.0037 Å) methoxy­carbonyl­methyl side chain form a dihedral angle of 84.67 (10)°. The crystal structure is stabilized by inter­molecular C—H⋯O hydrogen bonds. A triclinic polymorph of the title compound is already known [Siddiqui et al. (2008 ▶). Acta Cryst. E64, o859]