Study of ammonia borane and its derivatives: Influence of nanoconfinements and pressures

Recently, ammonia borane has increasingly attracted researchers’ attention because of its merging applications, such as organic synthesis, boron nitride compounds synthesis, and hydrogen storage. This dissertation presents the results from several studies related to ammonia borane. ^ The pressure-induced tetragonal to orthorhombic phase transition in ammonia borane was studied in a diamond anvil cell using in situ Raman spectroscopy. We found a positive Clapeyron-slope for this phase transformation in the experiment, which implies that the phase transition from tetragonal to orthorhombic is exothermic. The result of this study indicates that the rehydrogenation of the high pressure orthorhombic phase is expected to be easier than that of the ambient pressure tetragonal phase due to its lower enthalpy. ^ The high pressure behavior of ammonia borane after thermal decomposition was studied by in situ Raman spectroscopy at high pressures up to 10 GPa. The sample of ammonia borane was first decomposed at ∼140 degree Celcius and ∼0.7 GPa and then compessed step wise in an isolated sample chamber of a diamond anvil cell for Raman spectroscopy measurement. We did not observe the characteristic shift of Raman mode under high pressure due to dihydrogen bonding, indicating that the dihydrogen bonding disappears in the decomposed ammonia borane. Although no chemical rehydrogenation was detected in this study, the decomposed ammonia borane could store extra hydrogen by physical absorption. ^ The effect of nanoconfinement on ammonia borane at high pressures and different temperatures was studied. Ammonia borane was mixed with a type of mesoporous silica, SBA-15, and restricted within a small space of nanometer scale. The nano-scale ammonia borane was decomposed at ∼125 degree Celcius in a diamond anvil cell and rehydrogenated after applying high pressures up to ∼13 GPa at room temperature. The successful rehydrogenation of decomposed nano-scale ammonia borane gives guidance to further investigations on hydrogen storage. ^ In addition, the high pressure behavior of lithium amidoborane, one derivative of ammonia borane, was studied at different temperatures. Lithium amidoborane (LAB) was decomposed and recompressed in a diamond anvil cell. After applying high pressures on the decomposed lithium amidoborane, its recovery peaks were discovered by Raman spectroscopy. This result suggests that the decomposition of LAB is reversible at high pressures.^

Globalization and the Public Provision of Higher Education: Empirical Evidence from Selected Countries

This research study was designed to examine the relationship between globalization as measured by the KOF index, its related forces (economic, political, cultural and technological) and the public provision of higher education. This study is important since globalization is increasingly being associated with changes in critical aspects of higher education. The public provision of education was measured by government expenditure and educational outcomes; that is participation, gender equity and attainment. The study utilized a non-experimental quantitative research design. Data collected from secondary sources for 139 selected countries was analyzed. The countries were geographically distributed and included both developed and developing countries. The choice of countries for inclusion in the study was based on data availability. The data, which was sourced from international organizations such as the United Nations and the World Bank, were examined for different time periods using five year averages. The period covered was 1970 to 2009. The relationship between globalization and the higher education variables was examined using cross sectional regression analysis while controlling for economic, political and demographic factors. The major findings of the study are as follows. For the two spending models, only one revealed a significant relationship between globalization and education with the R2 s ranging from .222 to .448 over the period. This relationship was however negative indicating that as globalization increased, spending on higher education declined. However, for the education outcomes models, this relationship was not significant. For the sub-indices of globalization, only the political dimension showed significance as shown in the spending model. Political globalization was significant for six periods with R2 s ranging from .31 to .52. The study concluded that the results are mixed for both the spending and outcome models. It also found no robust effects of globalization on government education provision. This finding is not surprising given the existing literature which sees mixed results on the social impact of globalization.

The Relationship of Culturally Responsive Instruction and the Reading Comprehension and Attitude of Struggling Urban Adolescent Readers

Culturally responsive instruction refers to the identification of relevant cultural aspects of students’ lives and infusion of these into the curriculum. This instructional approach assumes that a culturally appropriate curriculum can potentially motivate, engage, and lead students to higher rates of achievement. This quasi-experimental study (N=44) investigated the relationship of culturally responsive instruction and the reading comprehension and attitude of struggling urban adolescent readers. The study incorporated the use of culturally responsive instruction using culturally relevant literature (CRL), the Bluford Series Novels, as authentic texts of instruction. Participants were seventh grade reading students at a Title I middle school in South Florida. After a baseline period, two different classes were taught for 8 weeks using different methods. One class formed the experimental group (n=22) and the other class formed the comparison group (n=22). The CRI curriculum for the experimental group embraced the socio-cultural perspective through the use of small discussion groups in which students read and constructed meaning with peers through interaction with the Bluford Series Novels; gave written responses to multiple strategies according to SCRAP – Summarize, Connect, Reflect, Ask Questions, Predict; responded to literal and inferential questions, while at the same time validating their responses through evidence from the text. The Read XL (basal reader) curriculum of the comparison group utilized a traditional form of instruction which incorporated the reading of passages followed by responses to comprehension questions, and teacher-led whole group discussion. The main sources of data were collected from the Gates-MacGinitie Reading Tests, the Florida Assessments for Instruction in Reading (FAIR), and the Rhody Secondary Reading Attitude Assessment. Statistical analyses were performed using Repeated Measures ANOVAs. Findings from the study revealed that the experimental participants’ reading attitudes and FAIR comprehension scores increased when compared to the comparison group. Overall, the results from the study revealed that culturally responsive instruction can potentially foster reading comprehension and a more positive attitude towards reading. However, a replication of this study in other settings with a larger, more randomized sample size and a greater ethnic variation is needed in order to make full generalizations.

From the workplace to the classroom:examining the impact of self-leadership learning strategies on higher educational attainment and success

Self-leadership is a concept from the organisational and management literature broadly combining processes of self-goal setting, self-regulation and self-motivation. Research has typically focused on the impact of self-leadership on work performance outcomes, with little attention to potential benefits for learning and development. In this paper, we employ a longitudinal design to examine the association of a number of processes of self-leadership with higher educational attainment in a sample of business students (N = 150). Self-reported use of strategies related to behavioural, cognitive and motivational aspects of self-leadership were measured in the first semester of the academic year, and correlated with end-of year grade point average. We found that in particular, self-goal setting, pro-active goal-related behaviour, behaviour regulation and direction, motivational awareness, and optimism were all significant predictors of educational attainment. We discuss implications for educational research and for teachers and tutors in practice.

Time-limited home-care reablement services for maintaining and improving the functional independence of older adults

Background: Reablement, also known as restorative care, is one possible approach to home-care services for older adults at risk of functional decline. Unlike traditional home-care services, reablement is frequently time-limited (usually six to 12 weeks) and aims to maximise independence by offering an intensive multidisciplinary, person-centred and goal-directed intervention. Objectives: To assess the effects of time-limited home-care reablement services (up to 12 weeks) for maintaining and improving the functional independence of older adults (aged 65 years or more) when compared to usual home-care or wait-list control group. Search methods: We searched the following databases with no language restrictions during April to June 2015: the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE (OvidSP); Embase (OvidSP); PsycINFO (OvidSP); ERIC; Sociological Abstracts; ProQuest Dissertations and Theses; CINAHL (EBSCOhost); SIGLE (OpenGrey); AgeLine and Social Care Online. We also searched the reference lists of relevant studies and reviews as well as contacting authors in the field. Selection criteria: We included randomised controlled trials (RCTs), cluster randomised or quasi-randomised trials of time-limited reablement services for older adults (aged 65 years or more) delivered in their home; and incorporated a usual home-care or wait-list control group. Data collection and analysis: Two authors independently assessed studies for inclusion, extracted data, assessed the risk of bias of individual studies and considered quality of the evidence using GRADE. We contacted study authors for additional information where needed. Main results: Two studies, comparing reablement with usual home-care services with 811 participants, met our eligibility criteria for inclusion; we also identified three potentially eligible studies, but findings were not yet available. One included study was conducted in Western Australia with 750 participants (mean age 82.29 years). The second study was conducted in Norway (61 participants; mean age 79 years). We are very uncertain as to the effects of reablement compared with usual care as the evidence was of very low quality for all of the outcomes reported. The main findings were as follows. Functional status: very low quality evidence suggested that reablement may be slightly more effective than usual care in improving function at nine to 12 months (lower scores reflect greater independence; standardised mean difference (SMD) -0.30; 95% confidence interval (CI) -0.53 to -0.06; 2 studies with 249 participants). Adverse events: reablement may make little or no difference to mortality at 12 months' follow-up (RR 0.97; 95% CI 0.74 to 1.29; 2 studies with 811 participants) or rates of unplanned hospital admission at 24 months (RR 0.94; 95% CI 0.85 to 1.03; 1 study with 750 participants). The very low quality evidence also means we are uncertain whether reablement may influence quality of life (SMD -0.23; 95% CI -0.48 to 0.02; 2 trials with 249 participants) or living arrangements (RR 0.92, 95% CI 0.62 to 1.34; 1 study with 750 participants) at time points up to 12 months. People receiving reablement may be slightly less likely to have been approved for a higher level of personal care than people receiving usual care over the 24 months' follow-up (RR 0.87; 95% CI 0.77 to 0.98; 1 trial, 750 participants). Similarly, although there may be a small reduction in total aggregated home and healthcare costs over the 24-month follow-up (reablement: AUD 19,888; usual care: AUD 22,757; 1 trial with 750 participants), we are uncertain about the size and importance of these effects as the results were based on very low quality evidence. Neither study reported user satisfaction with the service. Authors' conclusions: There is considerable uncertainty regarding the effects of reablement as the evidence was of very low quality according to our GRADE ratings. Therefore, the effectiveness of reablement services cannot be supported or refuted until more robust evidence becomes available. There is an urgent need for high quality trials across different health and social care systems due to the increasingly high profile of reablement services in policy and practice in several countries.

Enhancement of the total phenolic compounds and antioxidant activity of aqueous Citrus limon L. pomace extracts using microwave pre-treatment on the dry powder

The effect of microwave pre-treatment on the levels of total phenolic compounds, flavonoids, proanthocyanidins and individual major compounds as well as the total antioxidant activity of the dried lemon pomace was investigated. The results showed that microwave pre-treatment significantly affected all the examined parameters. The total phenolic content, total flavonoids, proanthocyanidins, as well as the total antioxidant activity significantly increased as the microwave radiation time and power increased (e.g., 2.5 folds for phenolics, 1.4 folds for flavonoids and 5.5 folds for proanthocyanidins), however irradiation more than 480 W for 5 min resulted in the decrease of these parameters. These findings indicate that microwave irradiation time and power may enhance higher levels of the phenolic compounds as well as the antioxidant capacity of the dried lemon pomace powder. However, higher and longer irradiation may lead to a degradation of phenolic compounds and lower the antioxidant capacity of the dried lemon pomace.

The teaching of reading English in a foreign language in Libyan universities: methods and models

This study focuses on the learning and teaching of Reading in English as a Foreign Language (REFL), in Libya. The study draws on an action research process in which I sought to look critically at students and teachers of English as a Foreign Language (EFL) in Libya as they learned and taught REFL in four Libyan research sites. The Libyan EFL educational system is influenced by two main factors: the method of teaching the Holy-Quran and the long-time ban on teaching EFL by the former Libyan regime under Muammar Gaddafi. Both of these factors have affected the learning and teaching of REFL and I outline these contextual factors in the first chapter of the thesis. This investigation, and the exploration of the challenges that Libyan university students encounter in their REFL, is supported by attention to reading models. These models helped to provide an analytical framework and starting point for understanding the many processes involved in reading for meaning and in reading to satisfy teacher instructions. The theoretical framework I adopted was based, mainly and initially, on top-down, bottom-up, interactive and compensatory interactive models. I drew on these models with a view to understanding whether and how the processes of reading described in the models could be applied to the reading of EFL students and whether these models could help me to better understand what was going on in REFL. The diagnosis stage of the study provided initial data collected from four Libyan research sites with research tools including video-recorded classroom observations, semi-structured interviews with teachers before and after lesson observation, and think-aloud protocols (TAPs) with 24 students (six from each university) in which I examined their REFL reading behaviours and strategies. This stage indicated that the majority of students shared behaviours such as reading aloud, reading each word in the text, articulating the phonemes and syllables of words, or skipping words if they could not pronounce them. Overall this first stage indicated that alternative methods of teaching REFL were needed in order to encourage ‘reading for meaning’ that might be based on strategies related to eventual interactive reading models adapted for REFL. The second phase of this research project was an Intervention Phase involving two team-teaching sessions in one of the four stage one universities. In each session, I worked with the teacher of one group to introduce an alternative method of REFL. This method was based on teaching different reading strategies to encourage the students to work towards an eventual interactive way of reading for meaning. A focus group discussion and TAPs followed the lessons with six students in order to discuss the 'new' method. Next were two video-recorded classroom observations which were followed by an audio-recorded discussion with the teacher about these methods. Finally, I conducted a Skype interview with the class teacher at the end of the semester to discuss any changes he had made in his teaching or had observed in his students' reading with respect to reading behaviour strategies, and reactions and performance of the students as he continued to use the 'new' method. The results of the intervention stage indicate that the teacher, perhaps not surprisingly, can play an important role in adding to students’ knowledge and confidence and in improving their REFL strategies. For example, after the intervention stage, students began to think about the title, and to use their own background knowledge to comprehend the text. The students employed, also, linguistic strategies such as decoding and, above all, the students abandoned the behaviour of reading for pronunciation in favour of reading for meaning. Despite the apparent efficacy of the alternative method, there are, inevitably, limitations related to the small-scale nature of the study and the time I had available to conduct the research. There are challenges, too, related to the students’ first language, the idiosyncrasies of the English language, the teacher training and continuing professional development of teachers, and the continuing political instability of Libya. The students’ lack of vocabulary and their difficulties with grammatical functions such as phrasal and prepositional verbs, forms which do not exist in Arabic, mean that REFL will always be challenging. Given such constraints, the ‘new’ methods I trialled and propose for adoption can only go so far in addressing students’ difficulties in REFL. Overall, the study indicates that the Libyan educational system is underdeveloped and under resourced with respect to REFL. My data indicates that the teacher participants have received little to no professional developmental that could help them improve their teaching in REFL and skills in teaching EFL. These circumstances, along with the perennial problem of large but varying class sizes; student, teacher and assessment expectations; and limited and often poor quality resources, affect the way EFL students learn to read in English. Against this background, the thesis concludes by offering tentative conclusions; reflections on the study, including a discussion of its limitations, and possible recommendations designed to improve REFL learning and teaching in Libyan universities.

How do medium naturalness and personality traits shape academic achievement and perceived learning? An experimental study of face-to-face and synchronous e-learning

This controlled experiment examined how academic achievement and cognitive, emotional and social aspects of perceived learning are affected by the level of medium naturalness (face-to-face, one-way and two-way videoconferencing) and by learners’ personality traits (extroversion–introversion and emotional stability–neuroticism). The Media Naturalness Theory explains the degree of medium naturalness by comparing its characteristics to face-to-face communication, considered to be the most natural form of communication. A total of 76 participants were randomly assigned to three experimental conditions: face-to-face, one-way and two-way videoconferencing. E-learning conditions were conducted through Zoom videoconferencing, which enables natural and spontaneous communication. Findings shed light on the trade-off involved in media naturalness: one-way videoconferencing, the less natural learning condition, enhanced the cognitive aspect of perceived learning but compromised the emotional and social aspects. Regarding the impact of personality, neurotic students tended to enjoy and succeed more in face-to-face learning, whereas emotionally stable students enjoyed and succeeded in all of the learning conditions. Extroverts tended to enjoy more natural learning environments but had lower achievements in these conditions. In accordance with the ‘poor get richer’ principle, introverts enjoyed environments with a low level of medium naturalness. However, they remained focused and had higher achievements in the face-to-face learning.

Behaviour of albino and melanic variants of Biomphalaria glabrata Say, 1818 (Mollusca: Planorbidae) following infection by Schistosoma mansoni Sambon, 1907

The behaviour of the albino and melanic variants of Biomphalaria glabrata of Belo Horizonte (MG. Brazil) was studied comparatively, in terms of their respective susceptibilities to infection by Schistosoma mansoni of the same origin, through observation of the elimination of cercariae for a three-month period and the calculation of mortality and infection rates, in control and in infected snails. The number of amoebocytes, granulocytes and hyalinocytes in the circulating hemolymph during different periods of infection was analyzed. The evolution of the infection in the tissues was observed by means of histological cross-sections. The melanic variant showed greater susceptibility to infection and a higher mortality rate. The albino variant showed a higher number of circulating amoebocytes, both granulocytes and hyalinocytes. A higher number of degenerated sporocysts were seen in the histological cross-sections of the albino variant. The results suggest that the melanic variant of B. glabrata was more susceptible to infection by S. mansoni than was the albino variant.

Formação docente no ensino superior de Química: contribuições dos programas de aperfeiçoamento de ensino

The literature on the challenges of teacher education in undergraduate chemistry teaching is limited. In the present study, the application of didactic proposals elaborated by two authors of this paper, graduate students and teaching assistants of the teaching improvement program at University of São Paulo, was investigated in terms of their contribution to the teaching assistants' education and undergraduate students' receptivity toward them. Such proposals were based on the jigsaw cooperative learning strategy and applied in two undergraduate courses. The results indicate students' good receptivity and suggest their importance to teaching assistants' education.

Effects of different levels of protein intake and physical training on growth and nutritional status of young rats

This study aimed to investigate the effects of physical training, and different levels of protein intake in the diet, on the growth and nutritional status of growing rats. Newly-weaned Wistar rats (n=48) were distributed into six experimental groups: three of them were subjected to physical swim training (1 h per day. 5 d per week, for 4 wk, after 2 wk of familiarization) and the other three were considered as controls (non-trained). Each pair of groups, trained and non-trained, received diets with a different level of protein in their composition: 14%. 21% or 28%. The animals were euthanized at the end of the training period and the following analyses were performed: proteoglycan synthesis as a biomarker of bone and cartilage growth, IGF-I (insulin-like growth factor-I) assay as a biomarker of growth and nutritional status. total RNA and protein concentration and protein synthesis measured in vivo using a large-dose phenylalanine method. As a main finding, increased dietary protein, combined with physical training, was able to improve neither tissue protein synthesis nor muscle growth. In addition, cartilage and bone growth seem to be deteriorated by the lower and the higher levels of protein intake. Our data allow us to conclude that protein enhancement in the diet, combined with physical exercise, does not stimulate tissue protein synthesis or muscle mass growth. Furthermore, physical training, combined with low protein intake, was not favorable to bone development in growing animals