School Refusal Behaviour in Primary School Students: A Demographic Analysis

School Refusal Behaviour (SRB) is an action, which is in another word a child-motivated refusal to attend school or difficulty remaining in class for an entire day. The objective of this study was to identify whether there are any differences in the demographic factors regarding SRB in primary school students in Selangor. Quantitative survey method was adopted as the method of this study. The survey was conducted at the end of school term in 2016, and students were recruited from 20 primary schools in six districts in Selangor with a total of 915 students from Year 4 and Year 5 participating. The sample of students had been absent from school for more than 15% of school days in the current year. Demographic measures were implemented and the study showed a high incidence rate of SRB in primary school students in Selangor (94.9%). The analysis showed there were no gender differences although the SRB in both categories were high (M=3.9). Similarly, the study also found there were no significant differences between single parent and two-parents; and low-class and middle-class family with SRB; although the occurrence of SRB in both categories were high

Human Rad51 mediated DNA unwinding is facilitated by conditions that favour Rad51-dsDNA aggregation

<p>Abstract</p> <p>Background</p> <p>Human Rad51 (RAD51), analogous to its bacterial homolog, RecA, binds and unwinds double stranded DNA (dsDNA) in the presence of certain nucleotide cofactors. ATP hydrolysis is not required for this process, because even ATP non hydrolysable analogs like AMP-PNP and ATPγS, support DNA unwinding. Even ADP, the product of ATP hydrolysis, feebly supports DNA unwinding.</p> <p>Results</p> <p>We find that human Rad52 (RAD52) stimulates RAD51 mediated DNA unwinding in the presence of all Adenine nucleotide cofactors, (except in AMP and no nucleotide conditions that intrinsically fail to support unwinding reaction) while enhancing aggregation of RAD51-dsDNA complexes in parallel. Interestingly, salt at low concentration can substitute the role of RAD52, in facilitating aggregation of RAD51-dsDNA complexes, that concomitantly also leads to better unwinding.</p> <p>Conclusion</p> <p>RAD52 itself being a highly aggregated protein perhaps acts as scaffold to bring together RAD51 and DNA molecules into large co-aggregates of RAD52-RAD51-DNA complexes to promote RAD51 mediated DNA unwinding reaction, when appropriate nucleotide cofactors are available, presumably through macromolecular crowding effects. Our work highlights the functional link between aggregation of protein-DNA complexes and DNA unwinding in RAD51 system.</p

FTIR study of bimetallic Pt-Sn/Al2O3 catalysts

A series of Pt-Sn/Al2O3 catalysts supported on Degussa nonporous alumina were characterized by infrared spectroscopy of adsorbed CO. The nominal platinum loading was kept constant in the catalysts at 1 wt% and the nominal amount of tin was varied from 0 to 5 wt%. At room temperature it was found that there was a general trend for the linearly adsorbed CO band to shift to lower frequencies with increasing amounts of tin in the catalyst, except for one of the catalysts (1.0 Pt-1.0 Sn/Al2O3) where a particle size effect seemed to be dominant. The amount of bridge-bonded CO species was very small and became undetectable in the case of large tin loadings (1 and 5 wt% Sn). Thermal desorption infrared spectroscopy was used to determine the vibration frequency of the isolated CO molecule and hence observe if there were any indications of electronic interactions between tin and platinum. For the monometallic 1.0 Pt/Al2O3 sample the singleton vibration frequency was 2041 cm-1. For all the Pt-Sn bimetallic samples it was found that the singleton vibration frequency lay within the range 2041 +/- 6 cm-1. This suggests that the electronic effect of Sn on Pt in our Pt-Sn/Al2O3 catalysts is not very large.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29705/1/0000037.pd

Neopentane reactions over bimetallic Pt---Sn/AI2O3 and Pt---Au/SiO2 catalysts

The reaction of 2,2-dimethylpropane (neopentane) with hydrogen was studied over two series of supported bimetallic catalysts containing platinum as the primary group VIII metal and either gold or tin as the second metallic component. In both catalyst series the platinum nominal loading was maintained constant at 1 wt%. The loading of the second metal component was varied. An effort has been made to better understand the reactivity trends in these catalysts, by bringing the neopentane reactivity data into context with previously obtained n-hexane reaction results and extensive catalyst characterization data. Small amounts of tin (1.0 Pt-0.1 Sn/Al2O3) caused the neopentane isomerization selectivity to drop in comparison to monometallic 1.0 Pt/Al2O3. However, further addition of tin up to 1.0 wt% caused the neopentane isomerization selectivity to increase above that of the monometallic 1.0 Pt/Al2O3 sample. On adding excess tin (5.0 wt%) the activity of the catalyst became prohibitively low. Hence, there seemed to be an optimum loading of tin giving desirable selectivity characteristics at reasonable activity levels. The differences in isomerization selectivity in the case of the Pt---Au/SiO2 catalysts were not as significant as those observed for the Pt---Sn/Al2O3 catalysts. The trends in catalytic behavior were consistent with previously measured n-hexane reaction trends and could be interpreted on the basis of microstructural differences between the bimetallic catalysts. The effect of gold appeared to be mainly a geometric one, disrupting larger Pt ensembles. On the other hand, the role of tin appeared to go beyond a simple geometric effect.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29012/1/0000041.pd

A chemisorption and XPS study of bimetallic Pt-Sn/Al2O3 catalysts

Bimetallic Pt-Sn/Al2O3 catalysts with nominally 1 wt% Pt and varying tin contents (0-3.25 wt%) prepared by coimpregnation of nonporous Degussa alumina were characterized by chemisorption of H2, O2, and CO at room temperature. The surface compositions and oxidation states of the reduced catalysts were tracked by XPS. Addition of tin to Pt resulted in significant differences in the gas uptake characteristics of the three adsorbates. Both H2 and CO showed an initial increase in gas uptake with addition of small amounts of tin, and then the chemisorbed amount tended to drop off with further addition of tin. In the case of O2 adsorption, there was a steady increase in gas uptake with increasing tin content. XPS of the reduced catalysts showed that in alumina-supported samples most of the tin was in a valence state of either Sn(II) or Sn(IV). On the other hand, large amounts of zero-valent tin were found in a SiO2-supported Pt-Sn catalyst which had been prepared from the same precursors and reduced under identical conditions. This supports the notion that interactions between the alumina support and tin prevent the complete reduction of tin.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29594/1/0000683.pd

Orthotopic Liver Transplantation in a Case of Novel YAP1-TFE3 Hepatic Epithelioid Hemangioendothelioma [HEHE]; Case Report and Review of Literature

Epithelioid hemangioendothelioma is an extremely rare vascular neoplasm arising in soft-tissues and different visceral organs, with liver being the most commonly involved viscera. Hepatic epithelioid hemangioendothelioma (HEHE) is a malignant tumour with an indolent behaviour and unpredictable clinical course. It has a better prognosis among the malignant tumours of the liver, in spite of being a diffuse multifocal liver disease or metastatic at the time of presentation. HEHE is usually found to be noted in the fifth decade with slight female preponderance. No single treatment strategy has yet been established owing to its variable clinical course, ranging from an indolent tumour with prolonged survival to an aggressive, metastatic disease with a fatal outcome. Here, we present a case of a novel HEHE in a 25-year-old female who was treated successfully with orthotopic living donor liver transplantation and discuss the presentation, histopathology and management of this rare, fatal yet treatable malignant tumour

Chemisorption and FTIR study of bimetallic Pt---Au/SiO₂catalysts

Pt/SiO₂, Au/SiO₂, and bimetallic Pt---Au/SiO₂ catalysts were prepared by incipient wetness impregnation of nonporous SiO₂. The catalysts were characterized after reduction in H₂ by static volumetric chemisorption and infrared spectroscopy. For the monometallic and the bimetallic catalysts, H₂, O₂, and CO were used as adsorbates at room temperature. Additionally, for the monometallic Au/SiO₂ catalyst, OZ adsorption at 473 K was also used. Infrared spectra of adsorbed CO were obtained on all catalysts. Addition of gold decreased the uptake of all three adsorbates at room temperature, without significantly influencing the relative amounts of weakly held adsorbed species which could be removed upon pumping for 30 min. Agreeing with CO chemisorption data, the total integrated intensity of the linear CO band decreased with increasing Au content. The IR results indicated a predominantly geometric effect of Au causing a shift of the linear CO band to lower wavenumbers. The shift could be rationalized in terms of decreased dipole-dipole coupling of adsorbed CO species. The results are discussed within the context of a previous investigation using electron microscopy, TPR, and reactivity data. Portions of the bimetallic catalysts were subjected to three high-temperature oxidation/reduction cycles and characterized by static chemisorption of H₂ to investigate the effect of this thermal treatment on Pt dispersion.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28743/1/0000573.pd

Exploring the extent of transformational leadership in the context of Miri entrepreneurs

In this century entrepreneurs (leaders) are faced with significant challenges that require extraordinary leadership. The business environments are changing at a very fast pace with immense competition, changing needs of customers, increasingly global economy and the rapid changes in the technology. This paper investigates the transactional and transformational leadership styles among the Miri entrepreneurs by employing the approach based on the Bass’s Multifactor Leadership Questionnaire (MLQ). Miri was chosen as the area of study as it will be a resort city by the year 2005 and, hence, Miri needs entrepreneurs who demonstrate effective leadership styles to cope with the increasing dynamic and complex business environment. Moreover, the entrepreneurs must meet the increasing preference for transformational leadership styles among employees found in many studies in order to improve satisfaction and commitment of the workforce. The findings were mapped with various literatures with the intention to enhance understanding of the leadership styles of Miri entrepreneurs and to further promote effective leadership styles amongst them. This research identified the leadership style of Miri entrepreneurs as transformational rather than transactional. This finding is consistent with the findings of transformational and transactional leadership styles in the Malaysian context undertaken by Sheh (2002) and Ng et al. (2002)

Cytomegalovirus replication steps and the actions of antiviral drugs

Human cytomegalovirus (HCMV) is a beta herpesvirus that inflicts an active infection in the fetus and immunosuppressive patients. The virus encodes many proteins that work together with cellular factors to achieve virus replication. In addition to vaccines, antiviral drugs can be deployed to manipulate how the virus replicates and minimize its pathogenicity. The five antiviral drugs approved by the Food and Drug Administration (FDA) have shown adverse reactions and the antiviral drug resistance were reported. Hence, this warrants the need for urgent development of a novel antiviral drug. Detailed understanding of the virus replication steps and how cellular signals interact with these steps will be key for pharmacological developments of for anti HCMV drugs. This review summarized all the drugs that target the virus proteins and cell signals that mediate CMV replication