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161.
Yasir Hasan Siddique Tanveer Beg Mohammad Afzal 《Indian journal of clinical biochemistry : IJCB》2009,24(3):294-300
Hydrogen peroxide is one of the reactive oxygen species for cellular injury. It is overproduced during oxidative stress and
is known to damage proteins, nucleic acids and cell membranes. The present study was aimed to study the protective effect
of ascorbic acid against the toxic doses of hydrogen peroxide using lipid peroxidation and cytokinesis blocked micronucleus
assay. Hydrogen peroxide was studied at 50, 100 and 200μM and was found to increase a dose dependent increase in lipid peroxidation
and micronuclei frequency. The treatment of 100 and 200μM of hydrogen peroxide separately along with 20, 40 and 80μM of ascorbic
acid showed a dose dependent decrease in the lipid peroxidation and micronuclei frequency. The results suggest a protective
effect of ascorbic acid against the hydrogen peroxide induced oxidative damage in cultured human peripheral blood lymphocytes. 相似文献
162.
University mathematics is often presented in a formal way that causes many students to cope by memorising what they perceive
as a fixed body of knowledge rather than learning to think for themselves. This research studies the effects on students'
attitudes of a course encouraging co-operative problem-solving and reflection on the thinking activities involved. The attitudinal
questionnaire was shown to the students' teachers who were asked to specify the attitudes they expect from their students
and the attitudes they prefer. This was used to give a ‘desired direction of change’ from expected to preferred. Before the
course, half the students responded that university mathematics did not make sense. A majority declared negative attitudes
such as anxiety, fear of new problems and lack of confidence. During the problem-solving course the changes were almost all
in the desired direction. During the following six months of standard mathematics lecturing, almost all changes were in the
opposite direction.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
163.
This article is a product of in‐depth research in Yaffa, The Arab Democratic School that was carried out in 2004/05, as part of a study on alternative Arab education in Israel. Its aim, beyond telling the story of Yaffa, is to explicate the motivations that underlay this initiative, and to examine parental choice amongst the disadvantaged. We ask how the Arabs’ parental choice is affected by their (marginalised) social location, by how far they are from the dominant culture, and by their (in)capacity to make a difference. Apparently, to make a choice is a multidimensional act, reflecting the Palestinian citizens’ resistance to their marginalisation and unwillingness to be subjugated through non‐democratic educational perceptions. Their positionality resonates in Yaffa, as an act of intervention, and their search for an alternative reality where democratic education is not and cannot be separated from the Palestinian citizens’ need to imagine themselves as Arabs. 相似文献
164.
Recent studies show that reduction in cross-sectional area can be used to improve the concentration factor in microscale bioseparations. Due to simplicity in fabrication process, a step reduction in cross-sectional area is generally implemented in microchip to increase the concentration factor. But the sudden change in cross-sectional area can introduce significant band dispersion and distortion. This paper reports a new fabrication technique to form a gradual reduction in cross-sectional area in polymethylmethacrylate (PMMA) microchannel for both anionic and cationic isotachophoresis (ITP). The fabrication technique is based on hot embossing and surface modification assisted bonding method. Both one-dimensional and two-dimensional gradual reduction in cross-sectional area microchannels were formed on PMMA with high fidelity using proposed techniques. ITP experiments were conducted to separate and preconcentrate fluorescent proteins in these microchips. Thousand fold and ten thousand fold increase in concentrations were obtained when 10 × and 100 × gradual reduction in cross-sectional area microchannels were used for ITP. 相似文献
165.
The performance of complementary feeders, running in parallel, can be significantly improved by installing static transfer switches (STSs) at critical locations. We develop the STS control logic, which transfers the critical load from the preferred feeder to the alternate feeder when a voltage sag or a fault occurs on the preferred feeder. A forced commutation technique is proposed and implemented to turn off the preferred feeders' thyristor, thus avoiding cross current to flow and minimizing the transfer time. Simulation results show that the forced commutation technique is more effective as compared to the recently proposed time delay technique for STS operation. Two different feeders, namely New Exchange, the preferred feeder, and Sector 1-10/2, the alternate feeder of Islamabad Electric Supply COmpany (IESCO), Pakistan, have been selected for case studies. The software PSCAD/EMTDC professional package has been used for simulation. 相似文献
166.
Mohammad Alauddin Asaduzzaman Khan 《Educational Assessment, Evaluation and Accountability》2010,22(4):293-305
This paper investigates whether performance in progressive assessment necessarily influences the outcome in the end-of-semester
final examination using the experience of an introductory postgraduate statistics course at a large Australian university.
The average score on progressive assessments was higher than that of the final examination. Students attaining a higher distinction
(HD) at the progressive assessment had a 37% chance of securing the same grade in the final examination, while students securing
just a pass grade at the progressive assessment had 54 percent chance of failure in the final examination. Multiple regression
analysis revealed that students’ performance in progressive assessments had a significant positive impact on final examination,
so has the impact of learning diary. Mid-semester tests based exclusively on multiple choice questions (MCQs), more weights
in progressive assessment and class-size appeared to have significant negative impact on the performance in the final examination.
Focus group discussions suggest that (a) the final examination under timed conditions; (b) competing demands on time for final
examination in other courses due contemporaneously; and (c) weaker motivation to sustain the momentum due to pass or near
pass based on progressive assessments were the main hurdles in achieving better performance in the final examination. 相似文献
167.
Mo’ath F. Bataineh Ali M. Al-Nawaiseh Mohammad H. Abu Altaieb David M. Bellar Omar S. Hindawi 《European Journal of Sport Science》2018,18(3):357-366
Mouth rinsing using a carbohydrate (CHO) solution has been suggested to improve physical performance in fasting participants. This study examined the effects of CHO mouth rinsing during Ramadan fasting on running time to exhaustion and on peak treadmill speed (Vpeak). In a counterbalanced crossover design, 18 sub-elite male runners (Age: 21?±?2 years, Weight: 68.1?±?5.7?kg, VO2max: 55.4?±?4.8?ml/kg/min) who observed Ramadan completed a familiarization trial and three experimental trials. The three trials included rinsing and expectorating a 25?mL bolus of either a 7.5% sucrose solution (CHO), a flavour and taste matched placebo solution (PLA) for 10?s, or no rinse (CON). The treatments were performed prior to an incremental treadmill test to exhaustion. Three-day dietary and exercise records were obtained on two occasions and analysed. Anthropometric characteristics were obtained and recorded for all participants. A main effect for mouth rinse on peak velocity (Vpeak) (CHO: 17.6?±?1.5?km/h; PLA: 17.1?±?1.4?km/h; CON: 16.7?±?1.2?km/h; P?.001, ηp2?=?0.49) and time to exhaustion (CHO: 1282.0?±?121.3?s; PLA: 1258.1?±?113.4?s; CON: 1228.7?±?98.5?s; P?=?.002, ηp2?=?0.41) was detected, with CHO significantly higher than PLA (P?.05) and CON (P?.05). Oxygen consumption, heart rate, respiratory exchange ratio, and rating of perceived exertion were not significantly different between treatments or trials (P?>?.05). Energy availability from dietary analysis, body weight, and fat-free mass did not change during the last two weeks of Ramadan (P?>?.05). This study concludes that carbohydrate mouth rinsing improves running time to exhaustion and peak treadmill speed under Ramadan fasting conditions. 相似文献
168.
ABSTRACTThis paper analyzes the process of crack saturation, which is fundamental to understanding why panel paintings have survived remarkably well in the uncontrolled environments of historic houses or places of worship for several centuries. The process of crack saturation was analyzed using finite element modeling. A double layer elastic model with fractured overlying paint layer was subjected to uniaxial tension. The critical separation between cracks was determined and compared with patterns observed in real paintings. In addition, the generation and propagation of delamination were studied to elucidate the effect of their propagation on the saturation distance of cracks, as well as the load carrying ability of the paint layer. Contributing modes of crack propagation and their significance are also discussed. The results demonstrate that shearing fracture mode dominates the process of delamination. The impact of crack saturation on the degree of relative humidity variation that is allowable is also discussed. 相似文献
169.
Mohammad M. N. Esfahani Mark D. Tarn Tahmina A. Choudhury Laura C. Hewitt Ashley J. Mayo Theodore A. Rubin Mathew R. Waller Martin G. Christensen Amy Dawson Nicole Pamme 《Biomicrofluidics》2016,10(1)
The ability to engage and inspire younger generations in novel areas of science is important for bringing new researchers into a burgeoning field, such as lab-on-a-chip. We recently held a lab-on-a-chip workshop for secondary school students, for which we developed a number of hands-on activities that explained various aspects of microfluidic technology, including fabrication (milling and moulding of microfluidic devices, and wax printing of microfluidic paper-based analytical devices, so-called μPADs), flow regimes (gradient formation via diffusive mixing), and applications (tissue analysis and μPADs). Questionnaires completed by the students indicated that they found the workshop both interesting and informative, with all activities proving successful, while providing feedback that could be incorporated into later iterations of the event. 相似文献
170.
Mohammad Tubishat Norisma Idris Mohammad A.M. Abushariah 《Information processing & management》2018,54(4):545-563
Sentiment analysis is a text classification branch, which is defined as the process of extracting sentiment terms (i.e. feature/aspect, or opinion) and determining their opinion semantic orientation. At aspect level, aspect extraction is the core task for sentiment analysis which can either be implicit or explicit aspects. The growth of sentiment analysis has resulted in the emergence of various techniques for both explicit and implicit aspect extraction. However, majority of the research attempts targeted explicit aspect extraction, which indicates that there is a lack of research on implicit aspect extraction. This research provides a review of implicit aspect/features extraction techniques from different perspectives. The first perspective is making a comparison analysis for the techniques available for implicit term extraction with a brief summary of each technique. The second perspective is classifying and comparing the performance, datasets, language used, and shortcomings of the available techniques. In this study, over 50 articles have been reviewed, however, only 45 articles on implicit aspect extraction that span from 2005 to 2016 were analyzed and discussed. Majority of the researchers on implicit aspects extraction rely heavily on unsupervised methods in their research, which makes about 64% of the 45 articles, followed by supervised methods of about 27%, and lastly semi-supervised of 9%. In addition, 25 articles conducted the research work solely on product reviews, and 5 articles conducted their research work using product reviews jointly with other types of data, which makes product review datasets the most frequently used data type compared to other types. Furthermore, research on implicit aspect features extraction has focused on English and Chinese languages compared to other languages. Finally, this review also provides recommendations for future research directions and open problems. 相似文献