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The Trends in International Mathematics and Science Study (TIMSS) is an influential mathematics and science assessment administered at fourth and eighth grades in around 60 countries across the world. Under current practices, TIMSS does not support claims about teachers unless the inference is drawn as a student characteristic ("Half of the eighth graders in the country have mathematics teachers with Master's degrees."). With this in mind, this paper proposes and tests through a simulation study two methods that would allow for teacher-centric inferences ("More than half of the eighth-grade mathematics teachers have Master's degrees.") if links between sampled teachers and the unsampled yet eligible classes were known. The first method posits that with such links inverse-probability weights could be calculated, and the second method, the Multiplicity-Adjusted Indirect Sampling (MAIS) approach, posits that teacher estimates could be obtained by adjusting downward the classroom weights based on these links. • Discusses teacher reporting in Trends in International Mathematics and Science Study. • One method creates and implements inverse-probability weights for teachers. • Another method reweights the class weights for each teacher. • A simulation study shows that both methods produce unbiased results. • Both methods would require collecting data on teachers' links to unsampled classes. [ABSTRACT FROM AUTHOR]

Focuses on a study which assessed the effect of Smad4 and Apc genotypes in carcinogen-induced pancreatic lesions in the mouse. List of genes identified as mutated in pancreatic cancer; Information on adenomatous polyposis coli; Way in which the role of SMAD4 in colorectal tumor progression was established.

Tumour suppressor genes prevent cancer development. They can be identified by studying humans, but a full understanding of the mechanisms of their action requires the production of animal models. Mice with mutations in tumour suppressor genes can be produced by gene targeting. The phenotypic consequences of tumour suppressor gene mutations in mice and humans show parallels and contrasts, and both can contribute to the elucidation of disease processes. [ABSTRACT FROM AUTHOR]

Indoor nitrogen dioxide exposure has been associated with respiratory symptoms in children in many studies, but in Australia, levels and sources of nitrogen dioxide in homes have not been well-characterized. Therefore, as part of a larger indoor environmental study, conducted in the Latrobe Valley, Victoria, nitrogen dioxide was monitored using passive samplers in 80 homes. Samples were collected on five occasions over one year. Mean indoor levels were higher than outdoor levels, and a seasonal variation was evident, with highest levels recorded in winter. The overall median level was 11.6 µg/m³ (6.0 ppb), ranging from <0.7 to 246 µg/m³ (128 ppb). Major indoor nitrogen dioxide sources were: gas stoves, vented gas heaters, and smoking. Some 67% of variation in indoor nitrogen dioxide levels could be explained by presence of major sources, house age, and outdoor levels. Gas stoves were the main contributors. [ABSTRACT FROM AUTHOR]

Abstract: Volatile organic compounds (VOCs) exist widely in both the indoor and outdoor environment. The main contributing sources of VOCs are motor vehicle exhaust and solvent utilization. Some VOCs are toxic and carcinogenic to human health, such as benzene. In this study, TiO2–SiO2 based photocatalysts were synthesized using the sol–gel method, with high surface areas of 274.1–421.1m2/g obtained. Two types of pellets were used as catalysts in a fixed-bed reactor installed with a UV black light lamp. Experiments were conducted to compare their efficiencies in degrading the VOCs. Toluene was used as the VOC indicator. When the toluene laden gas stream passed through the photocatalytic reactor, the removal efficiencies were determined using a FTIR multi-gas analyser, which was connected to the outlet of the reactor to analyse the toluene concentrations. As the TiO2–SiO2 pellets used have a high adsorption capacity, they had dual functions as a photocatalyst and adsorbent in the hybrid photocatalysis and adsorption system. The experiments demonstrated that the porous photocatalyst with very high adsorptive capacity enhanced the subsequent photocatalysis reactions and lead to a positive synergistic effect. The catalyst can be self-regenerated by photocatalytic oxidation of the adsorbed VOCs. When the UV irradiation and feeding gas is continuous, a destruction efficiency of about 25% was achieved over a period of 20h. Once the system was designed and operated into adsorption/regeneration mode, a higher removal efficiency of about 55% was maintained. It was found that the catalyst pellets with a higher surface area (421m2/g) achieved higher conversion efficiency (100%) for a longer period than those with a lower surface area. A full spectrum scan was carried out using a Bio-rad Infrared spectrometer, finding that the main components of the treated gas stream leaving the reactor, along with untreated toluene, were CO2 and water. The suspected intermediates of aliphatic hydrocarbons and CO were found in minimal amounts or were non detectable. The kinetic rate constants were calculated from the experimental results, it appeared that the stronger adsorption capacity, i.e. larger specific surface area, the higher conversion efficiency would be achieved. [Copyright &y& Elsevier]

The building permission process is to a large extent an analogue process where much information is handled in paper format or as pdf files. With the ongoing digitalisation in society, there is a potential to automate this process by integrating Building Information Models (BIM) of planned buildings and geospatial data to check if a building conforms to the building permission regulations. In this study, an inventory of which regulations in the (Swedish) detailed development plans that can be automatically checked or supported by 3D visualisation was conducted. Then, two of these regulations, the building height and the building footprint area, were studied in detail to find to which extent they can be automatically checked by integration of BIM and geospatial data. In addition, a feasibility study of one visual criterion was conducted. One concern when automating the building permission process is the variability of content within the Industry Foundation Classes (IFC) data model. Variations in modelling methods and model content leads to differences in IFC models' content and structure; these differences complicate automated processes. To facilitate automated processes, requirements on the production of IFC models for building permission applications could be defined in the form of model view definitions or delivery specifications. [ABSTRACT FROM AUTHOR]

Abstract: To examine the roles of endogenous K-ras 4A and K-ras 4B splice variants in tumorigenesis, murine lung carcinogenesis was induced by N-methyl-N-nitrosourea (MNU), which causes a K-ras mutation (G12D) that jointly affects both isoforms. Compared with age-matched K-ras tmΔ4A/− mice (where tumours can express mutationally activated K-ras 4B only), tumour number and size were significantly higher in K-ras +/− mice (where tumours can also express mutationally activated K-ras 4A), and significantly lower in K-ras tmΔ4A/tmΔ4A mice (where tumours can express both wild-type and activated K-ras 4B). MNU induced significantly more, and larger, tumours in wild-type than K-ras tmΔ4A/tmΔ4A mice which differ in that only tumours in wild-type mice can express wild-type and activated K-ras 4A. Lung tumours in all genotypes were predominantly papillary adenomas, and tumours from K-ras +/− and K-ras tmΔ4A/− mice exhibited phospho-Erk1/2 and phospho-Akt staining. Hence (1) mutationally activated K-ras 4B is sufficient to activate the Raf/MEK/ERK(MAPK) and PI3-K/Akt pathways, and initiate lung tumorigenesis, (2) when expressed with activated K-ras 4B, mutationally activated K-ras 4A further promotes lung tumour formation and growth (both in the presence and absence of its wild-type isoform) but does not affect either tumour pathology or progression, and (3) wild-type K-ras 4B, either directly or indirectly, reduces tumour number and size. [Copyright &y& Elsevier]

Background: Alterations in gene splicing occur in human sporadic colorectal cancer (CRC) and may contribute to tumour progression. The K-ras proto-oncogene encodes two splice variants, Kras 4A and 4B, and K-ras activating mutations which jointly affect both isoforms are prevalent in CRC. Past studies have established that splicing of both the K-ras oncogene and proto-oncogene is altered in CRC in favour of K-ras 4B. The present study addressed whether the K-Ras 4A protooncoprotein can suppress tumour development in the absence of its oncogenic allele, utilising the ApcMin/+ (Min) mouse that spontaneously develops intestinal tumours that do not harbour K-ras activating mutations, and the K-rastmΔ4A/tmΔ4A mouse that can express the K-ras 4B splice variant only. By this means tumorigenesis in the small intestine was compared between ApcMin/+, K-ras+/+ and ApcMin/+, K-rastmΔ4A/tmΔ4A mice that can, and cannot, express the K-ras 4A proto-oncoprotein respectively. Methods: The relative levels of expression of the K-ras splice variants in normal small intestine and small intestinal tumours were quantified by real-time RT-qPCR analysis. Inbred (C57BL/6) ApcMin/+, K-ras+/+ and ApcMin/+, K-rastmΔ4A/tmΔ4A mice were generated and the genotypes confirmed by PCR analysis. Survival of stocks was compared by the Mantel-Haenszel test, and tumour number and area compared by Student's t-test in outwardly healthy mice at approximately 106 and 152 days of age. DNA sequencing of codons 12, 13 and 61 was performed to confirm the intestinal tumours did not harbour a K-ras activating mutation. Results: The K-ras 4A transcript accounted for about 50% of K-ras expressed in the small intestine of both wild-type and Min mice. Tumours in the small intestine of Min mice showed increased levels of K-ras 4B transcript expression, but no appreciable change in K-ras 4A transcript levels. No Kras activating mutations were detected in 27 intestinal tumours derived from Min and compound mutant Min mice. K-Ras 4A deficiency did not affect mouse survival, or tumour number, size or histopathology. Conclusion: The K-Ras 4A proto-oncoprotein does not exhibit tumour suppressor activity in the small intestine, even though the K-ras 4A/4B ratio is reduced in adenomas lacking K-ras activating mutations. [ABSTRACT FROM AUTHOR]

Abstract: Ras proteins function as molecular switches in signal transduction pathways, and, here, we examined the effects of the K-ras4A and 4B splice variants on cell function by comparing wild-type embryonic stem (ES) cells with K-ras tmΔ4A/tmΔ4A (exon 4A knock-out) ES cells which express K-ras4B only and K-ras −/− (exons 1–3 knock-out) ES cells which express neither splice variant, and intestinal epithelium from wild-type and K-ras tmΔ4A/tmΔ4A mice. RT-qPCR analysis found that K-ras4B expression was reduced in K-ras tmΔ4A/tmΔ4A ES cells but unaffected in small intestine. K-Ras deficiency did not affect ES cell growth, and K-Ras4A deficiency did not affect intestinal epithelial proliferation. K-ras tmΔ4A/tmΔ4A and K-ras −/− ES cells showed a reduced capacity for differentiation following LIF withdrawal, and K-ras −/− cells were least differentiated. K-Ras4A deficiency inhibited etoposide-induced apoptosis in ES cells and intestinal epithelial cells. However, K-ras tmΔ4A/tmΔ4A ES cells were more resistant to etoposide-induced apoptosis than K-ras −/− cells. The results indicate that (1) K-Ras4A promotes apoptosis while K-Ras4B inhibits it, and (2) K-Ras4B, and possibly K-Ras4A, promotes differentiation. The findings raise the possibility that alteration of the K-Ras4A/4B isoform ratio modulates tumorigenesis by differentially affecting stem cell survival and/or differentiation. However, K-Ras4A deficiency did not affect life expectancy or spontaneous overall tumor incidence in aging mice. [Copyright &y& Elsevier]

In mammals, the three classical ras genes encode four highly homologous proteins, N-Ras, H-Ras, and the isoforms K-Ras 4A and 4B. Previous studies have shown that K-ras is essential for mouse development and that while K-ras 4A and 4B are expressed during development, K-ras 4A expression is regulated temporally and spatially and occurs in adult kidney, intestine, stomach, and liver. In the present study, the pattern of K-ras 4A expression was examined in a wide range of wild-type adult mouse tissues, and gene targeting was used to generate K-ras 4A-deficient mice to examine its role in development. It was found that K-ras 4A is also expressed in uterus, lung, pancreas, salivary glands, seminal vesicles, bone marrow cells, and cecum, where it was the major K-Ras isoform expressed. Mating between K-ras[sup tmΔ4A/+] mice produced viable K-ras[sup tmΔ4A/tmΔ4A] offspring with the expected Mendelian ratios of inheritance, and these mice expressed the K-ras 4B splice variant only. K-ras[sup tmΔ4A/tmΔ4A] mice were fertile and showed no histopathological abnormalities on inbred (129/Ola) or crossbred (129/Ola × C57BL/6) genetic backgrounds. The results demonstrate that K-Ras 4A, like H- and N-Ras, is dispensable for normal mouse development, at least in the presence of functional K-Ras 4B. [ABSTRACT FROM AUTHOR]

Air samples of particulate matter (PM) with an aerodynamic diameter less than 10 µm (PM10) were collected from six sites in Bangkok, Thailand, using high-volume air samplers. Daily samples were taken at intervals of 12 days from November 1999 to November 2000. Size-selected sampling using a multislit Andersen size-fractionated cascade impactor was undertaken at one site in central Bangkok to identify particulate size distribution. The annual average PM10 concentration at all six sites exceeded the Thailand National Ambient Air Quality Standard (NAAQS) of 50 µg/m3. The daily PM10 concentrations at heavy traffic roadside areas ranged between 30 and 160 µg/m3. The highest PM10 level occurred during the winter period (November–February), which is the dry season. From our results, which are based on a 1-yr survey, it can be observed that the particulate concentrations are associated with traffic volumes and seasonal factors (temperature and rainfall). The relative importance of size fractions in contributing to PM load is presented and discussed. Twenty polycyclic aromatic hydro-carbons (PAHs) associated with PM have been identified and quantified. The summed PAHs based on the 20 species had an average concentration of 60 ng/m3. Benzo(e)pyrene, indeno(123cd)pyrene, and benzo(ghi)perylene were the major compounds with average concentrations of 8, 10, and 13 ng/m3, respectively. Results indicate that more than 97% of PAHs were found in the small particulate size range of <0.95 µm. [ABSTRACT FROM AUTHOR]

Aerosol samples were collected with Gent PM10 stacked filter unit (SFU) samplers at Bukit Tinggi, a mountain site on Sumatra, and at Pontianak, a sea-level site on Kalimantan. The Gent PM10 SFU sampler provides two size fractions: coarse (2–10 μm equivalent aerodynamic diameter (EAD)) and fine (<2 μm EAD). At Bukit Tinggi, 130 SFU samples were taken from April 1996 to August 1999, and at Pontianak, 66 samples from the end of December 1997 to June 1999. All samples were analysed for the particulate mass (PM), black carbon (BC), and up to 47 elements. A combination of particle-induced X-ray emission spectrometry and instrumental neutron activation analysis was used for the multielemental analyses. The average fine-to-coarse ratios were at both sites around 1 for the PM, but above 2 (up to 5) for BC, S, Sb, I and Pb. The median PM concentrations (and interquartile ranges) in the coarse size fraction were 4.8 (3.8–5.6) and 12 (9–14) μg/m3 at Bukit Tinggi and Pontianak, respectively. For the fine fraction, the corresponding numbers were 4.5 (2.6–9.1) and 9.4 (6.5–13) μg/m3. Principal component analysis was applied to the fine fraction data sets in order to identify the contributing sources (source types). At Bukit Tinggi, five components were identified, i.e., a crustal component, a biomass burning component (with loadings of 0.7–0.9 for BC, K, Br, Rb and I), an oil combustion component (with S and V), a pollution component (with Sb and Pb), and a Na component. [Copyright &y& Elsevier]

The indoor environment of 80 houses in the Latrobe Valley, Victoria, Australia was assessed during six visits performed bi-monthly over a period of one year. Children between 7 and 14 years of age residing in the houses were included, result ing in 148 study children, 53 of whom were asthmatic. A respiratory health questionnaire was completed and skin prick tests performed. Significant risk factors for asthma were: exposure to a gas stove (OR=3.I5, 95% CI 1.28-7.72), and indoor pets (OR= 2.68, 95% CI 1.07-6.70). Exposure to airborne Aspergillus spores {+10 CFU/m&sup1, OR =1.51, 95% CI 1.05-2.18) was a risk factor for atopy, while exposure to a gas stove (OR=2.32, 95% CI 1.04-5.18) was a risk factor for respiratory symptoms. In conclusion, exposure to gas stoves, fungal spores and pets in the home were identified as statistically significant risk factors for respiratory health in children. [ABSTRACT FROM AUTHOR]

Defects of mismatch repair are thought to be responsible for carcinogenesis in hereditary non-polyposis colorectal cancer and about 15% of sporadic colon cancers. The phenotype is seen as microsatellite instability and is known to be caused either by mutations in mismatch repair genes or by aberrant methylation of these genes stabilizing their downregulation. Lack of repair of microsatellite sequence errors, created during replication, leads to a mutation-prone phenotype. Where mutations occur within mononucleotide tracts within exons they cause translation frameshifts, premature cessation of translation and abnormal protein expression. Such mutations have been observed in the TGFβRII, BAX, IGFIIR, MSH3 and MSH6 genes in colon and other cancers. We describe here frameshift mutations affecting the gene for the methyl-CpG binding thymine glycosylase, MBD4, in over 40% of microsatellite unstable sporadic colon cancers. The mutations all appear heterozygous but their location would ensure truncation of the protein between the methyl-CpG binding and glycosylase domains, thus potentially generating a dominant negative effect. It is thus possible that such mutations enhance mutation frequency at other sites in these tumours. A suggestion has been made that MBD4 (MED1) mutations may lead to an increased rate of microsatellite instability but this mechanism appears unlikely due to the nature of mutations we have found. [ABSTRACT FROM AUTHOR]