Thermal Analysis of Cellulose Fibres Extracted from Locally Available Rice Straw

Agriculture sector plays a vital role in Sri Lankan economy. Although the country is moving towards industrialisation, the agricultural sector still contributes substantially to both foreign exchange earnings and GDP. Paddy is cultivated in almost all parts of the country, except at very high altitudes. In 2018, around 3.9 million metric tonnes of paddy was harvested across the country from both Yala and Maha seasons. Rice straw is a by-product from the paddy cultivation and identified as agricultural production residue that is generated in equal or greater quantities than the rice itself with no commercial interest. Therefore, it is of ecological and economical point of view to discover an advantageous utilization of this material. Agricultural crop residues are rich in lignocellulosic materials with cellulose as the principle constituent. Study on the thermal properties of rice straw fibers are important in order to estimate their industrial applications. In this study, cellulose fibers were extracted from rice straw (BG352) via a series of chemical treatments. The structure and chemical composition of cellulose fibers were investigated using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Thermal stability of each sample was determined using TGA SDT Q600 simultaneous thermal analyser (TA instruments, Delaware, USA). Analysis of individual samples was carried out at a constant heating rate of 10 °C/min between ambient temperature to 700o C in a nitrogen atmosphere. FTIR analysis of fibers demonstrate that the chemical purification treatment results in sequential and complete removal of hemicellulose (1729 cm-1, carbonyl stretching), lignin (1516 cm-1, aromatic skeletal vibrations) and silica (796 cm-1 and 466 cm-1, Si–O–Si stretching). XRD results also reveal the removal of lignin (shoulder peak at 16.4o) and hemicellulose (weak peak at 34.76o) from rice straw thus, confirms the final product as cellulose. Three endothermic peaks were observed in thermogravimetric analysis. Initially a small weight loss was observed around 100o C due to the low molecular weight components in the fibers and the evaporation of remained moisture. Hemicellulose pyrolysis was occurred around 260o C. A resistant increase in cellulose was observed due to the removal of almost all hemicelluloses from the rice straw. Pyrolysis of lignin in rice straw started at 200o C and persisted till 700o C. Further, a significant difference between the contents of the residues were remained which indicated that the thermal stability of cellulose was visibly improved. Based on the results obtained, the extracted cellulose fibers from locally available rice straw could be used to produce textiles, composites, all kinds of paper and paper boards, photographic films, moisture proof coatings for food packaging and other fibrous products similar to those produced from the synthetic fibers. Using rice straw as a source of high-quality fibrous applications will add value to the rice crops, mitigate concerns regarding burning or disposing of rice straw, and provide an environmentally friendly alternative to replace the synthetic fibers currently in use.Keywords: Sri Lankan rice straw, Cellulose fibers, Chemical treatment, Thermal decomposition, Thermal propertie

Using Social Media to Promote STEM Education: Matching College Students with Role Models

STEM (Science, Technology, Engineering, and Mathematics) fields have become increasingly central to U.S. economic competitiveness and growth. The shortage in the STEM workforce has brought promoting STEM education upfront. The rapid growth of social media usage provides a unique opportunity to predict users' real-life identities and interests from online texts and photos. In this paper, we propose an innovative approach by leveraging social media to promote STEM education: matching Twitter college student users with diverse LinkedIn STEM professionals using a ranking algorithm based on the similarities of their demographics and interests. We share the belief that increasing STEM presence in the form of introducing career role models who share similar interests and demographics will inspire students to develop interests in STEM related fields and emulate their models. Our evaluation on 2,000 real college students demonstrated the accuracy of our ranking algorithm. We also design a novel implementation that recommends matched role models to the students.Comment: 16 pages, 8 figures, accepted by ECML/PKDD 2016, Industrial Trac

POTENTIAL EXPLOITATION OF Eucalyptus AND Pinus SOILS AS ALTERNATE SOURCES OF NURSERY MEDIA IN TEA - AN EXAMPLE OF SUSTAINABLE NATURALRESOURCE MANAGEMENT.

Tea nurseries require large amounts of soils to cater the plant requirement for newplanting, replanting and infilling. Conventionally, soils from natural forests and Mana(Cymbopogon confertiflorus) lands are being used. At present, land use laws, populationincrease, housing and diversification etc. make these soils scarce in both plantation andsmall holder sectors. Therefore, this study explored the potentials of Eucalyptus, Pinusand old tea soils as alternative nursery soil resources found in the proximity of tea areasand also known to have caused environmental degradation.Eucalyptus and Pinus soils were significantly deficient in organic matter, Nand C:Nratio compared to that of forest, Mana and old tea soils. All soil sources possessedfavourable soil physical properties and pH levels for tea propagation but no plantpathogenic nematode populations.Callus formation in Eucalyptus and Pinus soils was similar to forest soils which wassignificantly greater than that of Mana and old tea soils. Interestingly, Pinus soilsexhibited early callusing; forest soils lead longer and greater root biomass of nursery teaplants followed by Eucalyptus and Pinus soils.Therefore, these results confirmed the potentials of harnessing Eucalyptus and Pinussoils as alternative sources for tea propagation owing to solve the practical limitationswith use of forest and Mana soils as well as possible dissemination of soil bornepathogens with use of old tea soils. The study also opens avenues for maximizingutilization of natural resources of introduced plantation forests in the vicinity of teagrowing areas for agricultural purposes.Attributes for early callusing and root growth observed with Eucalyptus and Pinus soilsare being investigated at present. Studies on overall nursery performance of tea, costbenefit and environmental impact assessments due to large-scale use of such soils arealso underway for further confirmation.

Successful Non-Surgical Root Canal Treatment on Auto- Transplanted Maxillary Premolar with Apical Periodontitis

Auto-transplantation is a procedure that replaces traumatized or congenitally missing teeth. While most auto-transplanted teeth are successfully integrated into recipient sites, the donor tooth may develop apical periodontitis, causing early failure. In the present case report, the periodontic resident performed the procedure on a 15-year-old male by selecting donor teeth #4 and #13 and transplanting them at recipient sites #29 and #20, respectively. After 6 weeks, the patient was referred to the endodontic resident for evaluation of tooth #20 due to symptom development. While one auto-transplanted tooth (donor tooth #4, recipient site #29) was successfully integrated, the other (donor tooth #13, recipient site #20) was unsuccessful: the patient was diagnosed with pulp necrosis and a chronic apical abscess. Because of the patient’s age, collaboration among periodontic, endodontic, and orthodontic residents/specialists informed the clinical decision to pursue non-surgical root canal treatment (NSRCT) rather than extraction. The canal was cleaned and shaped to a size #80 using copious irrigation of 2.5% sodium hypochlorite (NaOCl), followed by 17% ethylenediaminetetraacetic acid (EDTA) via the EndoVac Negative Pressure Irrigation system. The tooth was dried with paper points, and then calcium hydroxide was mixed with 2.5% NaOCl and placed with an amalgam carrier 2mm from the radiographic apex. The tooth was next temporized with Teflon tape and Fuji TRIAGE. Four weeks later, after confirming the patient was asymptomatic and tooth mobility had decreased, the canal was obturated using EndoSequence Bioceramic Root Repair Material Fast Set Putty in 2mm incremental layers to achieve a threedimensional fill and create an apical plug to prevent gutta-percha extrusion, then backfilled in incremental layers of guttapercha to the cementoenamel junction (CEJ). At the 8-month follow-up, the patient was asymptomatic, and the periodontal ligament (PDL) had no signs of periapical pathology. When teeth undergoing auto-transplantation procedures develop apical periodontitis, NSRCT can be implemented

Association of the TLR4 Asp299Gly polymorphism with lung function in relation to body mass index

<p>Abstract</p> <p>Background</p> <p>Previous studies have shown conflicting results for the association between TLR4 polymorphism (Asp299Gly) and lung function. We investigated the influence of TLR4 Asp299Gly, a polymorphism, on lung function in a community population.</p> <p>Methods</p> <p>In 2003, a cross-sectional survey was conducted to assess the respiratory health of residents living in and around the town of Humboldt, Saskatchewan, Canada. There were 2090 adults age 18-79 years who completed a questionnaire that included a medical and smoking history, as well as socio-economic and lifestyle variables. Genetic information and lung function test measurements were available on 1725 subjects (754 males and 971 females) of the 2090 respondents. These subjects were selected for further analysis to investigate the association between TLR4 Asp299Gly genotype and forced expiratory volume in the first second in liters (FEV₁), forced vital capacity in liters (FVC), FEV₁/FVC ratio, and forced expiratory flow rate in liters/second (FEF_25-75). Multivariable linear regression analysis was used to investigate associations.</p> <p>Results</p> <p><b>A</b>djusted mean values of FEV₁and FVC were significantly different between TLR4 wild type and TLR4 variant groups [Mean ± S.E.: (TLR4 wild type - FEV₁: 3.18 ± 0.02, FVC: 3.95 ± 0.03; TLR4 variant - FEV₁: 3.31 ± 0.06, FVC: 4.14 ± 0.07)]. Based on multivariable regression analysis, we observed that body mass index (BMI) was associated with decreased FEV₁/FVC ratio and FEF_25-75in TLR4 variant group but not in wild type group.</p> <p>Conclusion</p> <p>BMI may modify the associations of TLR4 Asp299Gly polymorphism with FEV₁/FVC ratio and FEF_25-75.</p

Modeling of longitudinal polytomous outcome from complex survey data - application to investigate an association between mental distress and non-malignant respiratory diseases

<p>Abstract</p> <p>Background</p> <p>The data from longitudinal complex surveys based on multi-stage sampling designs contain cross-sectional dependencies among units due to clustered nature of the data and within-subject dependencies due to repeated measurements. Special statistical methods are required to analyze longitudinal complex survey data.</p> <p>Methods</p> <p>Statistics Canada's longitudinal National Population Health Survey (NPHS) dataset from the first five cycles (1994/1995 to 2002/2003) was used to investigate the effects of demographic, social, life-style, and health-related factors on the longitudinal changes of mental distress scores among the NPHS participants who self-reported physician diagnosed respiratory diseases, specifically asthma and chronic bronchitis. The NPHS longitudinal sample includes 17,276 persons of all ages. In this report, participants 15 years and older (n = 14,713) were considered for statistical analysis. Mental distress, an ordinal outcome variable (categories: no/low, moderate, and high) was examined. Ordered logistic regression models based on the weighted generalized estimating equations approach were fitted to investigate the association between respiratory diseases and mental distress adjusting for other covariates of interest. Variance estimates of regression coefficients were computed by using bootstrap methods. The final model was used to predict the probabilities of prevalence of no/low, moderate or high mental distress scores.</p> <p>Results</p> <p>Accounting for design effects does not vary the significance of the coefficients of the model. Participants suffering with chronic bronchitis were significantly at a higher risk (OR_adj= 1.37; 95% CI: 1.12-1.66) of reporting high levels of mental distress compared to those who did not self-report chronic bronchitis. There was no significant association between asthma and mental distress. There was a significant interaction between sex and self-perceived general health status indicating a dose-response relationship. Among females, the risk of mental distress increases with increasing deteriorating (from excellent to very poor) self-perceived general health.</p> <p>Conclusions</p> <p>A positive association was observed between the physician diagnosed self-reported chronic bronchitis and an increased prevalence of mental distress when adjusted for important covariates. Variance estimates of regression coefficients obtained from the sandwich estimator (i.e. not accounting for design effects) were similar to bootstrap variance estimates (i.e. accounting for design effects). Even though these two sets of variance estimates are similar, it is more appropriate to use bootstrap variance estimates.</p

Ethnicity and incidence of Hodgkin lymphoma in Canadian population

<p>Abstract</p> <p>Background</p> <p>Research has shown that ethnicity is a significant predictor of Hodgkin lymphoma (HL). Variations in cancer incidence among ethnic groups in the same country can lead to important information in the search for etiological factors. Other risk factors important in the etiology of HL are medical history and exposure to pesticides. In this report we investigated the association between ethnicity and HL in the presence of medical history, and exposure to pesticides.</p> <p>Methods</p> <p>The data resulting from a matched population-based case-control study conducted in six provinces of Canada (Ontario, Quebec, Manitoba, Saskatchewan, Alberta, and British Columbia) was analyzed to determine whether or not there was any association between ethnicity and incidence of HL when adjusted for personal medical history and pesticide exposure. Information on ethnicity, personal medical history, and pesticide exposure was collected by questionnaires via mail on 316 men diagnosed with HL; and on 1506 controls. A conditional logistic regression was utilized and results were presented as odds ratios and 95% confidence intervals.</p> <p>Results</p> <p>In our study population, the distribution of ethnic groups was: 38.5% North American, 15% British, 8.4% Western European, 8.2% Eastern European, 1.7% Asian, 1.4% Scandinavian and 27% of other ethnic origin. Compared to North Americans (i) the risk of HL was greater among the Eastern European descendents (Odds Ratio (OR_adj): 1.82; 95% confidence interval (CI): 1.02, 3.25) and Western European (OR_adj: 1.62; 95% CI: 0.95–2.76) descent population (borderline significance at 5% level); and (ii) the risk of HL was lower in Asian descents. Diagnosis with measles (OR_adj: 0.72, 95% C.I.: 0.53–0.98) and/or positive history of allergy desensitization shots (OR_adj: 0.55, 95% C.I.: 0.30–0.99) were negatively associated with the incidence of HL, while diagnosis with acne (OR_adj: 2.12, 95% C.I.: 1.19–3.78), shingles (OR_adj: 2.41, 95% C.I.: 1.38–4.22) and positive family history of cancer (OR_adj: 1.93, 95% C.I.: 1.40–2.65) increased the risk of HL. Exposure to individual herbicide dichlorprop showed an increased risk of HL (OR_adj: 6.35, 95% C.I.: 1.56–25.92).</p> <p>Conclusion</p> <p>In Canada, compared to North Americans descendents, the risk of HL was significantly greater among the Eastern European and Western European descent population. Our results related to association between ethnicity and HL support the findings reported by other researchers. Our data showed that subjects who were diagnosed with measles or had allergy desensitization shots negatively associated with the incidence of HL; and other medical conditions, ever diagnosed with acne, and positive family history of cancer were positively associated with the incidence of HL.</p

Clustering of cancer among families of cases with Hodgkin Lymphoma (HL), Multiple Myeloma (MM), Non-Hodgkin's Lymphoma (NHL), Soft Tissue Sarcoma (STS) and control subjects

<p>Abstract</p> <p>Background</p> <p>A positive family history of chronic diseases including cancer can be used as an index of genetic and shared environmental influences. The tumours studied have several putative risk factors in common including occupational exposure to certain pesticides and a positive family history of cancer.</p> <p>Methods</p> <p>We conducted population-based studies of Hodgkin lymphoma (HL), Multiple Myeloma (MM), non-Hodgkin's Lymphoma (NHL), and Soft Tissue Sarcoma (STS) among male incident case and control subjects in six Canadian provinces. The postal questionnaire was used to collect personal demographic data, a medical history, a lifetime occupational history, smoking pattern, and the information on family history of cancer. The family history of cancer was restricted to first degree relatives and included relationship to the index subjects and the types of tumours diagnosed among relatives. The information was collected on 1528 cases (HL (n = 316), MM (n = 342), NHL (n = 513), STS (n = 357)) and 1506 age ± 2 years and province of residence matched control subjects. Conditional logistic regression analyses adjusted for the matching variables were conducted.</p> <p>Results</p> <p>We found that most families were cancer free, and a minority included two or more affected relatives. HL [(OR_adj(95% CI) <b>1.79 (1.33, 2.42)]</b>, MM <b>(1.38(1.07, 1.78))</b>, NHL <b>(1.43 (1.15, 1.77)</b>), and STS cases <b>(1.30(1.00, 1.68)) </b>had higher incidence of cancer if any first degree relative was affected with cancer compared to control families. Constructing mutually exclusive categories combining "family history of cancer" (yes, no) and "pesticide exposure ≥10 hours per year" (yes, no) indicated that a positive family history was important for HL <b>(2.25(1.61, 3.15))</b>, and for the combination of the two exposures increased risk for MM <b>(1.69(1.14,2.51))</b>. Also, a positive family history of cancer both with <b>(1.72 (1.21, 2.45)) </b>and without pesticide exposure <b>(1.43(1.12, 1.83)) </b>increased risk of NHL.</p> <p>Conclusion</p> <p>HL, MM, NHL, and STS cases had higher incidence of cancer if any first degree relative affected with cancer compared to control families. A positive family history of cancer and/or shared environmental exposure to agricultural chemicals play an important role in the development of cancer.</p