Search results for: white coat
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 1000

Search results for: white coat

730 Development of Rh/Ce-Zr-La/Al2O3 TWCs’ Wash Coat: Effect of Reactor on Catalytic and Thermal Stability

Authors: Su-Ning Wang, Yao-Qiang Chen

Abstract:

The CeO2-ZrO2-La2O3-Al2O3 composite oxides are synthesized using co-precipitation method by two different reactors (i.e. continuous stirred-tank reactor and batch reactor), and the corresponding Rh-only three-way catalysts are obtained by wet-impregnation approach. The textural, structural, morphology and redox properties of the support materials, as well as the catalytic performance of the Rh-only catalyst are investigated systematically. The results reveal that the materials (CZLA-C) synthesized by continuous stirred-tank reactor have a better physic-chemical properties than the counterpart material (CZLA-B) prepared by batch reactor. After aging treatment at 1000 ℃ for 5 h, the BET surface area and pore volume of S1 reach up to 76 m2 g-1 and 0.36 mL/g, respectively, which is higher than that of S2. The XRD and Raman results demonstrate that a high structural stability is obtained by S1 because of the negligible lattice variation and the slight grain growth after aging treatment. The SEM and TEM images display that the morphology of S1 is assembled by many homogeneous primary nanoparticles (about 6.12 nm) that are connected to form mesoporous structure The TPR measurement shows that S1 possesses a higher reduction ability than S2. Compared with the catalyst supported on the CZLA-B, the as-prepared CZLA-C demonstrates an improved three-way catalytic activity both before and after aging treatment.

Keywords: composite oxides, reactor, catalysis, catalytic performance

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729 Influence of Resin Finishes on Properties of Khadi Fabric

Authors: Shivi Rastogi, Suman Pant

Abstract:

Khadi is an Indian fabric and also known by another name “Khaddar”. During pre-independence era, the movement of khadi manufacturing gained momentum. Over the years, khadi fabrics that were generally considered as the “second skin” of the Swadesh revolutionists changed its uniqueness. It underwent a metamorphosis from that of a patriot’s fabric, and a farmer’s apparel, to become a “fashion fabric”. Drape of garment is governed by draping quality of fabric used. Drape is an essential parameter to decide both appearance and handle of fabric. It is also a secondary determinant of fabric mechanical properties as influenced by the low stress properties, like bending length, formability, tensile and shear properties and compressibility of the fabric. In finishing, fabric is treated to add something to coat the fabric or fiber and thereby temporarily or permanently fix. Film forming agents such as thermoplastic and thermosetting resins and other surface deposits alter hand. In this study, resins were used to modify fabric hand. Three types of resins have been applied on the khadi fabric at three concentration. The effect of these finishes on drapeability, crease recovery, stiffness, tearing strength and smoothness of khadi fabrics were assessed. Silicone gave good results in imparting properties specially drape, smoothness and softness and hand of cotton and khadi fabric. KES result also showed that silicone treated samples enhanced THV rating amongst all treated samples when compared to the control fabric.

Keywords: crease recovery, drapeability, KES, silicone, THV

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728 Effect of Local Processing Techniques on the Nutrients and Anti-Nutrients Content of Bitter Cassava (Manihot Esculenta Crantz)

Authors: J. S. Alakali, A. R. Ismaila, T. G. Atume

Abstract:

The effects of local processing techniques on the nutrients and anti-nutrients content of bitter cassava were investigated. Raw bitter cassava tubers were boiled, sundried, roasted, fried to produce Kuese, partially fermented and sun dried to produce Alubo, fermented by submersion to produce Akpu and fermented by solid state to produce yellow and white gari. These locally processed cassava products were subjected to proximate, mineral analysis and anti-nutrient analysis using standard methods. The result of the proximate analysis showed that, raw bitter cassava is composed of 1.85% ash, 20.38% moisture, 4.11% crude fibre, 1.03% crude protein, 0.66% lipids and 71.88% total carbohydrate. For the mineral analysis, the raw bitter cassava tuber contained 32.00% Calcium, 12.55% Magnesium, 1.38% Iron and 80.17% Phosphorous. Even though all processing techniques significantly increased the mineral content, fermentation had higher mineral increment effect. The anti-nutrients analysis showed that the raw tuber contained 98.16mg/100g cyanide, 44.00mg/100g oxalate 304.20mg/100g phytate and 73.00mg/100g saponin. In general all the processing techniques showed a significant reduction of the phytate, oxalate and saponin content of the cassava. However, only fermentation, sun drying and gasification were able to reduce the cyanide content of bitter cassava below the safe level (10mg/100g) recommended by Standard Organization of Nigeria. Yellow gari(with the addition of palm oil) showed low cyanide content (1.10 mg/100g) than white gari (3.51 mg/100g). Processing methods involving fermentation reduce cyanide and other anti-nutrients in the cassava to levels that are safe for consumption and should be widely practiced.

Keywords: bitter cassava, local processing, fermentation, anti-nutrient.

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727 Formulation and Evaluation of Piroxicam Hydrotropic Starch Gel

Authors: Mohammed Ghazwani, Shyma Ali Alshahrani, Zahra Abdu Yousef, Taif Torki Asiri, Ghofran Abdur Rahman, Asma Ali Alshahrani, Umme Hani

Abstract:

Background and introduction: Piroxicam is a nonsteroidal anti-inflammatory drug characterized by low solubility-high permeability used to reduce pain, swelling, and joint stiffness from arthritis. Hydrotropes are a class of compounds that normally increase the aqueous solubility of insoluble solutes. Aim: The objective of the present research study was to formulate and optimize Piroxicam hydrotropic starch gel using sodium salicylate, sodium benzoate as hydrotropic salts, and potato starch for topical application. Materials and methods: The prepared Piroxicam hydrotropic starch gel was characterized for various physicochemical parameters like drug content estimation, pH, tube extrudability, and spreadability; all the prepared formulations were subjected to in-vitro diffusion studies for six hours in 100 ml phosphate buffer (pH 7.4) and determined gel strength. Results: All formulations were found to be white opaque in appearance and have good homogeneity. The pH of formulations was found to be between 6.9-7.9. Drug content ranged from 96.8%-99.4.5%. Spreadability plays an important role in patient compliance and helps in the uniform application of gel to the skin as gels should spread easily; F4 showed a spreadability of 2.4cm highest among all other formulations. In in vitro diffusion studies, extrudability and gel strength were good with F4 in comparison with other formulations; hence F4 was selected as the optimized formulation. Conclusion: Isolated potato starch was successfully employed to prepare the gel. Hydrotropic salt sodium salicylate increased the solubility of Piroxicam and resulted in a stable gel, whereas the gel prepared using sodium benzoate changed its color after one week of preparation from white to light yellowish. Hydrotropic potato starch gel proposed a suitable vehicle for the topical delivery of Piroxicam.

Keywords: Piroxicam, potato starch, hydrotropic salts, hydrotropic starch gel

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726 Evaluation of the Effect Rare Earth Metal on the Microstructure and Properties of Zn-ZnO-Y2O3 Coating of Mild Steel

Authors: A. P. I. Popoola, O. S. I. Fayomi, V. S. Aigbodion

Abstract:

Mild steel has found many engineering applications due to its great formability, availability, low cost and good mechanical properties among others. However its functionality and durability is subject of concern due to corrosion deterioration. Based on these Yttrium is selected as reinforcing particles using electroplating process in this work to enhance the corrosion resistance. Bath formulation of zinc-yttrium was prepared at moderated temperature and pH, to coat mild steel sample. Corrosion and wear behaviour were analyzed using electrochemical potentiostat and abrasive test rig. The composition and microstructure of coated films were investigated standard method. The microstructure of the deposited plate obtained from optimum (10%Yttrium) bath revealed fine-grained deposit of the alloy in the presence of condensation product and hence modified the morphology of zinc–yttrium alloy deposit. It is demonstrated that by adding yttria particles, mild steel can be strengthened with improved polarization behaviour and higher resistance to corrosive in sodium chloride solutions. Microhardness of the coating compared to plain mild steel have increased before and after heat treatment, and an increased wear resistance was also obtained from the modified coating of zinc-yttrium.

Keywords: microhardness, zinc-yttrium, coating, mild steel, microstructure, wear, corrosion

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725 Correlation of Hematological Indices with Fasting Blood Glucose Level and Anthropometric Measurements in Geriatric Diabetes Mellitus Subjects in Lagos State University Teaching Hospital, Ikeja, Lagos, Nigeria

Authors: Dada. O.Akinola, Uche. I. Ebele, Bamiro .A.Rafatu, Akinbami A. Akinsegun, Dada O. Adeyemi, Adeyemi. O. Ibukun, Okunowo O.Bolanle, Abdulateef O. Kareem, Ibrahim.N. Ismaila, Dosu Rihanat

Abstract:

Background: Hyperglycaemia alters qualitatively and quantitatively all the full blood count parameters. The alterations among other factors are responsible for the macrovascular and microvascular complications associated with diabetes mellitus (DM). This study is aimed at correlating haematological parameters in DM subjects with their fasting blood glucose (FBG) and anthropometric parameters. Materials and Methods: This was a cross-sectional study of participants attending DM clinic of Lagos State University Teaching Hospital (LASUTH), Ikeja. The study recruited one hundred and two (102) DM subjects and one hundred (100) non-DM controls. Venous blood samples were collected for full blood count (FBC) assay while FBG was done, structured questionnaires were administered, and anthropometric measurements of all participants were done. Data were analyzed with Statistical Package for Social Science (SPSS) version 23. P was set at ≤0.05. Results: The mean age of DM patients was 64.32± 11.31 years. Using a haemoglobin concentration cut-off of 11g/dl, 39.2%, and 13% DM and control participants respectively had values lower than 11g/dl. A total of 22.5% and 3% of DM and controls respectively gave a history of previous blood transfusion.White blood cells count and platelet count means were (6.12±1.60 and 5.30±7.52,p=0.59) and (213.31±73.58 and 228.91±73.21,p = 0.26) *109/L in DM subjects and controls respectively. FBG and all the anthropometric data in DM subjects were significantly higher than in controls. Conclusions: The prevalence of anaemia in DM subjects was three times higher than in controls. The white blood cell count was higher but not statistically significant in DM compared with controls. But platelet count was higher but not statistically significant in controls compared with DM subjects.

Keywords: haematological profile, diabetes mellitus, anthropometric data, fasting blood glucose

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724 Evaluation of Chromium Fortified-Parboiled Rice Coated with Herbal Extracts: Resistant Starch, and Glycemic Index

Authors: Wisnu Adi Yulianto, Chatarina Lilis Suryani, Mamilisti Susiati, Hendy Indra Permana

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Parboiled rice was developed to produce rice that has low glycemic index, especially for diabetics. Yet, parboiled rice is not enough because diabetics also lack of chromium. The sign of chromium (Cr) deficiency in diabetics is impaired glucose tolerance. Cr fortification was done for increasing Cr content in rice. Naturally-occurring compounds that have been proven to improve insulin sensitivity include Cr and polyphenol found in cinnamon, pandan and bay leaf. This research aimed to evaluate content of resistant starch and glycemic index of Cr - fortified - parboiled rice (Cr-PR) coated with herbal extracts. Variety of unhulled rice and forticant used in the experiment were Ciherang and CrCl3, respectively. Three herbal extracts used were cinnamon, pandan and bay leaf. Each concentration of herbal extracts in the amount of 3%, 6%, and 9% were added in the coating substance to coat Cr-PR. Resistant starch (RS) content was determined by enzymatic process through glucooxydase method. Testing of the GI was conducted on 18 non-diabetic volunteers. RS content of Cr-PR coated with herbal extracts ranged between 8.27 – 8.84 % (dry weight). Cr-PR coated with all herbal extracts of 3% concentration had higher RS content than the ones with herbal extracts of 6% and 9% concentration (P <0.05). Value of the rice GI ranged 29 - 40. The lowest GI (29-30) was attained by the rice coated with enrichment of 6-9% cinnamon extract.

Keywords: coating, Cr-fortified-parboiled rice, glycemic index, herbal extracts, resistant starch

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723 Protest Poetry in South Africa: A Study of Oswald Mbuyiseni Mtshali’s Sounds of a Cowhide Drum

Authors: Ogbu Harry Omilonye

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This paper examines protest as a literary mechanism against the unpopular political policy of the white minority regime in South Africa. It examines some of Mtshali’s poems as examples of protest poetry, showing how he deploys his artistic acumen in the popular struggle of the oppressed South Africans against the aberrations and obnoxious apartheid policy.

Keywords: protest poetry, poems, minority, oppression

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722 Active Exopolysaccharides Based Edible Coating Enriched with Red Seaweed (Gracilaria gracilis) Extract for Improved Preservation of Shrimp Quality during Refrigerated Storage

Authors: Rafik Balti, Mohamed Ben Mansour, Abdellah Arhaliass, Anthony Masse

Abstract:

Unfortunately, shrimps are highly perishable and they start deteriorating immediately after death owing to their high water content and nutritional components. Currently, there has been an increasing interest in bioactive edible films and coatings to preserve the freshness and quality of foods. In this study, active edible coatings from microalgal exopolysaccharides (EPS) enriched with different concentrations of Red Seaweed Extract (RSE) (0.5, 1 and 1.5 % (w/v)) were developed and their effects on the quality changes of white shrimp during refrigerated storage (4 ± 1 °C) were examined over a period of 8 days. The control and the coated shrimp samples were analyzed periodically for microbiological (total viable bacteria, psychrotrophic bacteria, and enterobacteriaceae counts), chemical (pH, TVB-N, TMA-N, PV, TBARS), textural and sensory characteristics. The results indicated that the coating with a mixture of EPS and RSE could significantly decrease the total volatile basic nitrogen (TVB-N), trimethylamine (TMA) and thiobarbituric acid reactive substances (TBARS) (p < 0.05). With storage, EPS coatings containing RSE at both levels (1 and 1.5 %) were more effective in inhibiting the microbial species studied, specially psychrotrophic bacteria. Also, EPS + RSE coated samples had lower polyphenol oxidase (PPO) activity and lipid oxidation (p < 0.05) toward the end of storage. Textural and color properties of coated shrimp were generally more acceptable. Sensory scores indicated no significant changes in all samples during storage. The obtained results indicate that the edible EPS coating solutions enriched with RSE have noticeable effects on the quality and shelf life of shrimps when compared to control group. Finally, the present work demonstrates the effectiveness of EPS enriched coatings, offering a promising alternative to preserve more better the quality characteristics and to extend the shelf life of shrimp during the refrigerated storage

Keywords: active coating, exopolysaccharides, red seaweed, refrigerated storage, white shrimp

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721 Meniscus Guided Film Coating for Large-Area Perovskite Solar Cells

Authors: Gizachew Belay Adugna, Yu-Tai Tao

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Perovskite solar cells (PSCs) have been gaining impressive progress with excellent power conversion efficiency (PCE) of 25.5% in small-area devices. However, the conventional film coating approach is not applicable to large-area module fabrication. Meniscus-guided coating, including blade coating, slot-die coating, and bar coating, is solution processing and promising for large-area and cost-effective film coating to industrial-scale PSCs. Here, we develop simple and scalable solution shearing (SS) and bar coating (BC) methods to coat all layers on large-area (10x10 cm²) substrate in FTO/c-TiO₂/mp-TiO₂/ CH₃NH₃PbI₃/Spiro-OMeTAD/Ag device structure, except the Ag electrode. All solution-sheared PSC exhibited a champion power conversion efficiency of 15.89% in the conational DMF/DMSO solvent. Whereas a very high PCE of 20.30% compared to the controlled spin-coated device (SC, 17.60%) was achieved from the large area sheared perovskite film in a green ACN/MA solvent. Similarly, a remarkable PCE of 18.50% was achieved for a device fabricated from a large-area perovskite film in a simpler and more compatible Bar-coating system. This strategy demonstrates the huge potential for module fabrication and future PSC commercialization.

Keywords: Perovskite solar cells, larger area film coating, meniscus-guided film coating, solution-shearing, bar-coating, power conversion efficiency

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720 Microbial Quality Assessment of Indian White Shrimp, Penaeus Indicus from Southwest Bangladesh

Authors: Saima Sharif Nilla, Mahmudur Rahman Khan, Anisur Rahman Khan, Ghulam Mustafa1

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The microbial quality of Indian white shrimp (Peneaus indicus) from Bagerhat, Khulna and Satkhira of southwest Bangladesh was assessed where the parameters varied with different sources and the quality was found to be poor for Satkhira shrimp samples. Shrimp samples in fresh condition were collected to perform the microbial assessment and 10 pathogenic isolates for antibiotic sensitivity test to 12 antibiotics. The results show that total bacterial count of all the samples were beyond the acceptable limit 105 cfu/g. In case of total coliform and E. coli density, no substantial difference (p<0.5) was found between the different shrimp samples from different districts and also high quantity of TC exceeding the limit (>102 cfu/g) proves the poor quality of shrimp. The FC abundance found in shrimps of Bagerhat and Satkhira was similar and significantly higher (p<0.5) than that of Khulna samples. No significant difference (p<0.5) was found among the high density of Salmonella-Shigella, Vibrio spp., and Staphylococcus spp. of the shrimp samples from the source places. In case of antibiotic sensitivity patterns, all of them were resistant to ampicillin, Penicillin and sensitive to kanamycin. Most of the isolates were frequently sensitive to ciprofloxacin and streptomycin in the sensitivity test. In case of nutritional composition, no significant difference (t-test, p<0.05) was found among protein, lipid, moisture and ash contents of shrimp samples. The findings prove that shrimp under this study was more or less contaminated and samples from Satkhira were highly privileged with food borne pathogens which confirmed the unhygienic condition of the shrimp farms as well as the presence of antibiotic resistance bacteria in shrimp fish supposed to threat food safety and deteriorate the export quality.

Keywords: food borne pathogens, satkhira, penaeus indicus, antibiotic sensitivity, southwest Bangladesh, food safety

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719 A Mixed Methods Study to Examine Teachers’ Views towards Using Interactive White Boards (IWBs) in Tatweer Primary Schools in Saudi Arabia

Authors: Azzah Alghamdi

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The Interactive White Boards (IWBs) as one of the innovative educational technologies have been extensively investigated in advanced countries such as the UK, US, and Australia. However, there is a significant lack of research studies, which mainly examine the use of IWBs in Saudi Arabia. Therefore, this study aims to investigate the attitudes of primary teachers towards using IWBs in both the teaching and learning processes. Moreover, it aims to investigate if there is any significant difference between male teachers and females regarding their attitudes towards using this technology. This study concentrated on teachers in primary schools, which participated in Tatweer project in the city of Jeddah, in Saudi Arabia. Mixed methods approach was employed in this study using a designed questionnaire, classroom observations, and a semi-structured interview. 587 teachers (286 men and 301 women) from Tatweer primary schools were completed the questionnaire as well as twenty teachers were interviewed including seven female teachers were observed in their classrooms. The findings of this study indicated that approximately 11% of the teachers within the sample (n=587) had negative attitudes towards the use of IWBs in the teaching and learning processes. However, the majority of them nearly 89% agreed about the benefits of using IWBs in their classrooms. Additionally, all the twenty teachers who were interviewed (including the seven observed female teachers) had positive attitudes towards the use of these technologies. Moreover, 87% of male teachers and 91% of female teachers who completed the questionnaire accepted the usefulness of using IWBs in improving their teaching and students' learning. Thus, this indicates that there was no significant difference between male and female teachers in Tatweer primary schools in terms of their views about using these innovative technologies in their lessons. The findings of the current study will help the Ministry of Education to improve the policies of using IWBs in Saudi Arabia. Indeed, examining teachers’ attitudes towards IWBs is a very important issue because they are the main users in classrooms. Hence, their views should be considered to addressing the powers and boundaries of using IWBs. Moreover, students will feel comfortable to use IWBs if their teachers accept and use them well.

Keywords: IWBs, Saudi teachers’ views, Tatweer schools, teachers' gender

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718 Plasma Treatment of Poppy and Flax Seeds in Fluidized Bed Reactor

Authors: Jakub Perner, Jindrich Matousek, Hana Malinska

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Adverse environmental conditions at planting (especially water shortage) can lead into reduced germination rate of seeds. The plasma treatment is one of the possibilities that can solve this problem. Such treatment can increase the germination rate of seeds and make germs grow faster due to increased wettability of seeds surface or disrupted seed coat. This could lead to enhanced oxygen and water transport into the seed and improve germination. Poppy and flax seeds were treated in fluidized bed reactor, and discharge power ranging from 10 to 40 W was used. The working gas was air at pressure 100 Pa. Poppy seeds were then planted into Petri dishes on 7 layers of filter paper saturated with water, and the number of germinated seeds was observed from 3 to 6 days after planting. Every plasma treated sample showed improved germination rate compared to untreated seeds (75.5%) six days after planting. Samples treated in 40W discharge had the highest germination rate (81.2%). The decreased contact angle of water on treated poppy seeds was observed from 85° (untreated) to 30–35° (treated). Untreated flax seeds have a germination rate over 98%; therefore, the weight of seeds was taken to be a measure of the successful germination. Treated flax seeds had a slightly higher weight than untreated. Also, the contact angle of water decreased from 99° (untreated) to 65-73° (treated); therefore the treatment of both species is considered to be successful.

Keywords: flax, germination, plasma treatment, poppy

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717 A Study on Prediction Model for Thermally Grown Oxide Layer in Thermal Barrier Coating

Authors: Yongseok Kim, Jeong-Min Lee, Hyunwoo Song, Junghan Yun, Jungin Byun, Jae-Mean Koo, Chang-Sung Seok

Abstract:

Thermal barrier coating(TBC) is applied for gas turbine components to protect the components from extremely high temperature condition. Since metallic substrate cannot endure such severe condition of gas turbines, delamination of TBC can cause failure of the system. Thus, delamination life of TBC is one of the most important issues for designing the components operating at high temperature condition. Thermal stress caused by thermally grown oxide(TGO) layer is known as one of the major failure mechanisms of TBC. Thermal stress by TGO mainly occurs at the interface between TGO layer and ceramic top coat layer, and it is strongly influenced by the thickness and shape of TGO layer. In this study, Isothermal oxidation is conducted on coin-type TBC specimens prepared by APS(air plasma spray) method. After the isothermal oxidation at various temperature and time condition, the thickness and shape(rumpling shape) of the TGO is investigated, and the test data is processed by numerical analysis. Finally, the test data is arranged into a mathematical prediction model with two variables(temperature and exposure time) which can predict the thickness and rumpling shape of TGO.

Keywords: thermal barrier coating, thermally grown oxide, thermal stress, isothermal oxidation, numerical analysis

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716 Captives on the Frontier: An Exploration of National Identity in Argentine Literature and Art

Authors: Carlos Riobo

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This paper analyzes literature and art in Argentina from the nineteenth to the twenty-first centuries as these media used the figure of the white female captive to define a developing national identity. This identity excluded the Indians whose lands the whites were taking and who appeared as the aggressors and captors in writing and paintings. The paper identifies the complicit relationship between art and history in crafting national memory. It also identifies a movement toward purity (as defined by separation of entities) and away from mestizaje (racial and cultural mixtures).

Keywords: Argentina, borders, captives, literature, painting

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715 Corn Flakes Produced from Different Cultivars of Zea Mays as a Functional Product

Authors: Milenko Košutić, Jelena Filipović, Zvonko Nježić

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Extrusion technology is thermal processing that is applied to improve the nutritional, hygienic, and physical-chemical characteristics of the raw material. Overall, the extrusion process is an efficient method for the production of a wide range of food products. It combines heat, pressure, and shear to transform raw materials into finished goods with desired textures, shapes, and nutritional profiles. The extruded products’ quality is remarkably dependent upon feed material composition, barrel temperature profile, feed moisture content, screw speed, and other extrusion system parameters. Given consumer expectations for snack foods, a high expansion index and low bulk density, in addition to crunchy texture and uniform microstructure, are desired. This paper investigates the effects of simultaneous different types of corn (white corn, yellow corn, red corn, and black corn) addition and different screw speed (350, 500, 650 rpm) on the physical, technological, and functional properties of flakes products. Black corn flour and screw speed at 350 rpm positively influenced physical, technological characteristics, mineral composition, and antioxidant properties of flake products with the best total score analysis of 0,59. Overall, the combination of Tukey's HSD test and PCA enables a comprehensive analysis of the observed corn products, allowing researchers to identify them. This research aims to analyze the influence of different types of corn flour (white corn, yellow corn, red corn, and black corn) on the nutritive and sensory properties of the product (quality, texture, and color), as well as the acceptance of the new product by consumers on the territory of Novi Sad. The presented data point that investigated corn flakes from black corn flour at 350 rpm is a product with good physical-technological and functional properties due to a higher level of antioxidant activity.

Keywords: corn types, flakes product, nutritive quality, acceptability

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714 Silver Nanoparticles Synthesized in Plant Extract Against Acute Hepatopancreatic Necrosis of Shrimp: Estimated By Multiple Models

Authors: Luz del Carmen Rubí Félix Peña, Jose Adan Felix-Ortiz, Ely Sara Lopez-Alvarez, Wenceslao Valenzuela-Quiñonez

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On a global scale, Mexico is the sixth largest producer of farmed white shrimp (Penaeus vannamei). The activity suffered significant economic losses due to acute hepatopancreatic necrosis (AHPND) caused by a strain of Vibrio parahaemolyticus. For control, the first option is the application of antibiotics in food, causing changes in the environment and bacterial communities, which has produced greater virulence and resistance of pathogenic bacteria. An alternative treatment is silver nanoparticles (AgNPs) generated by green synthesis, which have shown an antibacterial capacity by destroying the cell membrane or denaturing the cell. However, the doses at which these are effective are still unknown. The aim is to calculate the minimum inhibitory concentration (MIC) using the Gompertz, Richard, and Logistic model of biosynthesized AgNPs against a strain of V. parahaemolyticus. Through the testing of different formulations of AgNPs synthesized from Euphorbia prostrate (Ep) extracts against V. parahaemolyticus causing AHPND in white shrimp. Aqueous and ethanol extracts were obtained, and the concentration of phenols and flavonoids was quantified. In the antibiograms, AgNPs were formulated in ethanol extracts of Ep (20 and 30%). The inhibition halo at well dilution test were 18±1.7 and 17.67±2.1 mm against V. parahaemolyticus. A broth microdilution was performed with the inhibitory agents (aqueous and ethanolic extracts and AgNPs) and 20 μL of the inoculum of V. parahaemolyticus. The MIC for AgNPs was 6.2-9.3 μg/mL and for ethanol extract of 49-73 mg/mL. The Akaike index (AIC) was used to choose the Gompertz model for ethanol extracts of Ep as the best data descriptor (AIC=204.8, 10%; 45.5, 20%, and 204.8, 30%). The Richards model was at AgNPs ethanol extract with AIC=-9.3 (10%), -17.5 (20 and 30%). The MIC calculated for EP extracts with the modified Gompertz model were 20 mg/mL (10% and 20% extract) and 40 mg/mL at 30%, while Richard was winner for AgNPs-synthesized it was 5 μg/mL (10% and 20%) and 8 μg/mL (30%). The solver tool Excel was used for the calculations of the models and inhibition curves against V.parahaemolyticus.

Keywords: green synthesis, euphorbia prostata, phenols, flavonoids, bactericide

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713 Cloning, Expression and Protein Purification of AV1 Gene of Okra Leaf Curl Virus Egyptian Isolate and Genetic Diversity between Whitefly and Different Plant Hosts

Authors: Dalia. G. Aseel

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Begomoviruses are economically important plant viruses that infect dicotyledonous plants and exclusively transmitted by the whitefly Bemisia tabaci. Here, replicative form was isolated from Okra, Cotton, Tomato plants and whitefly infected with Begomoviruses. Using coat protein specific primers (AV1), the viral infection was verified with amplicon at 450 bp. The sequence of OLCuV-AV1 gene was recorded and received an accession number (FJ441605) from Genebank. The phylogenetic tree of OLCuV was closely related to Okra leaf curl virus previously isolated from Cameroon and USA with nucleotide sequence identity of 92%. The protein purification was carried out using His-Tag methodology by using Affinity Chromatography. The purified protein was separated on SDS-PAGE analysis and an enriched expected size of band at 30 kDa was observed. Furthermore, RAPD and SDS-PAGE were used to detect genetic variability between different hosts of okra leaf curl virus (OLCuV), cotton leaf curl virus (CLCuV), tomato yellow leaf curl virus (TYLCuV) and the whitefly vector. Finally, the present study would help to understand the relationship between the whitefly and different economical crops in Egypt.

Keywords: okra leaf curl virus, AV1 gene, sequencing, phylogenetic, cloning, purified protein, genetic diversity and viral proteins

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712 Photophysics and Photochemistry of Cross-Conjugated Y-Shaped Enediyne Fluorophores

Authors: Anuja Singh, Avik K. Pati, Ashok K. Mishra

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Organic fluorophores with π-conjugated scaffolds are important because of their interesting optoelectronic properties. In recent years, our lab has been engaged in understanding the photophysics of small diacetylene bridged fluorophores and found the diynes as a promising class of π-conjugated fluorophores. Building on this understanding, recently we have focused on the photophysics of a less explored class of cross-conjugated Y-shaped enediynes (one double and two triple bonds). Here we present the photophysical properties of such enediynes which show interesting photophysical properties that include dual emissions from locally excited (LE) and intramolecular charge transfer (ICT) states and ring size dependent aggregate fluorescence in non-aqueous media. The dyes also show prominent aggregate fluorescence in mixed-aqueous solvents and solid powder form. We further show that the solid state fluorescence can be reversibly switched multiple of cycles by external stimuli, highlighting their potential applications in solid states. The enediynes with push-pull electronic substituents/moieties exhibit high contrast fluorescence color switching upon continuous photon illumination. The intriguing photophysical outcomes of the enediynyl fluorophores are judiciously exploited to generate single-component white light emission in binary solvent mixtures and sense polar aprotic vapor in polymer film matrices. The photophysical behavior of the dyes is further successfully utilized to monitor the microenvironment changes of biologically relevant anisotropic media such as bile salts. In summary, the newly introduced cross-conjugated enediynes enrich the toolbox of organic fluorophores and vouch to display versatile applications.

Keywords: aggregation in solution and solid state, enediynes, physical photochemistry and photophysics, vapor sensing and white light emission

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711 Disability Policy and Leaders in México

Authors: Jennifer Isabelle Rios Rendón, Ursula Sanchez, Dana Lee Baker

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Disability Policy in México has witnessed numerous changed throughout the years. Physical disabilities are more often recognized in Mexican culture. However, with an emerging focus on neurological disabilities or differences in individuals’ new policies are needed to serve better and understand the needs of these populations. The need to understand and communicate with local leaders is imperative, as the lens used to analyze autism has historically been from a Western school of thought. We are looking to comprehend the disability policy subsystem in México - specifically how autism is perceived, the language used to describe it, and how it ties to the cultural stigma of disabilities that exist in México. Therefore, to understand this, we seek to interview multiple policy leaders on their experience in autism and disability policy. The goal is to conduct qualitative research through interviews with local autism and disability leaders in México. This methodology aims to answer the questions of what language commonly and culturally is utilized in disability policy, the context of how autism is perceived in México, and in general, the lived experience of the disability policy leaders that take part in this effort in México. Local activists and policy leaders were initially found through an online search then collected using snowball sampling. The interviews were conducted through a series of pre-formulated questions that the policy leader answered via email or a phone conversation with the researchers. Acknowledging the importance of language and accessibility, the need for the content to be in both English and Spanish as well as auditory and visual is essential to take steps in the inclusion of a Neurodiverse group of leaders. This work is a demonstration of the framework of the investigation which hopes to create a more complete understanding of the policy and political culture around autism in México. Results of the project include new insight into the developing relationship between the President Andrés Manuel López Obrador’s administration, disability activists, and neurodiverse communities. The project contributes to denormalizing the legacy of white supremacy in autism related, historically rooted in the assumption that autism occurs predominantly in white communities.

Keywords: autism, disability leaders, disability policy, México, Neurodiversity

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710 Using Artificial Neural Networks for Optical Imaging of Fluorescent Biomarkers

Authors: K. A. Laptinskiy, S. A. Burikov, A. M. Vervald, S. A. Dolenko, T. A. Dolenko

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The article presents the results of the application of artificial neural networks to separate the fluorescent contribution of nanodiamonds used as biomarkers, adsorbents and carriers of drugs in biomedicine, from a fluorescent background of own biological fluorophores. The principal possibility of solving this problem is shown. Use of neural network architecture let to detect fluorescence of nanodiamonds against the background autofluorescence of egg white with high accuracy - better than 3 ug/ml.

Keywords: artificial neural networks, fluorescence, data aggregation, biomarkers

Procedia PDF Downloads 672
709 Analyzing the Effects of a Psychological Intervention on Black Students’ Sense of Belonging in Physics and Math: Exploring Differential Impacts for Historically Black Colleges and Universities and Predominantly White Institutions

Authors: Terrell Strayhorn

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The lack of diversity in science, technology, engineering, and mathematics (STEM) fields is a persistent and concerning issue. One contributing factor to the underrepresentation of minority groups in STEM fields is a lack of sense of belonging, which can lead to lower levels of academic engagement, motivation, and achievement. In particular, Black students have been shown to experience lower levels of sense of belonging in STEM compared to their white peers. This study aimed to explore the effects of a psychological intervention on Black students' sense of belonging in physics and math courses at historically Black colleges and universities (HBCUs) and predominantly white institutions (PWIs). The study used a randomized controlled trial design and included 305 Black undergraduate students enrolled in physics or math courses at HBCUs and PWIs in the United States. Participants were randomly assigned to either an intervention group or a control group. The intervention consisted of a brief psychological, video-based intervention designed to enhance sense of belonging, which was delivered in a single session. The control group received no intervention. The primary outcome measure was sense of belonging in physics and math courses, as assessed by a validated self-report measure. Other outcomes included academic engagement, motivation, and achievement as measured by physics and math (course) grades. Preliminary results show that the intervention has a significant positive effect on Black students' sense of belonging in physics and math courses, with a moderate effect size. The intervention also had a significant positive effect on academic engagement and motivation, but not on academic achievement. Importantly, the effects of the intervention were larger for Black students enrolled at PWIs compared to those enrolled at HBCUs. Findings, at present, suggest that a brief psychological web-based intervention can enhance Black students' sense of belonging in physics and math courses, and that the effects may be particularly strong for Black students enrolled at PWIs, although they are not negligible for Black students at HBCUs. This is an important finding given the persistent underrepresentation of Black students in STEM fields, the growing number of Black students at PWIs, and the potential for enhancing sense of belonging to improve academic outcomes and increase diversity in these fields. The study has several limitations, including a relatively small sample size and a lack of long-term follow-up. Future research could explore the generalizability of these findings to other minority groups and other STEM fields, as well as the potential for longer-term interventions to sustain and enhance the effects observed in this study. Overall, this study highlights the potential for psychological interventions to enhance sense of belonging and improve academic outcomes for Black students in STEM courses, and underscores the importance of addressing sense of belonging as a key factor in promoting diversity and equity in STEM fields.

Keywords: sense of belonging, achievement, racial equity, postsecondary education, intervention

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708 From an Elderly Middle-Aged Man to ‘a Scientist May Be Anyone’: Draw-A-Scientist-Test in Nepalese Context

Authors: Pragya Paneru, Prativa Paneru

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This paper explores the attitude of high school Nepalese students toward scientists using a famous method named as Draw-A-Scientist-Test (DAST). A total of 145 students from Grade 11 and Grade 12 took part in this research and drew images of scientists. The findings indicated gender imbalance with male dominance in the images of scientists. The result also showed some usual stereotypes relating to hair, equipment, objects, use of eyeglasses, and lab coat in the drawings of scientists. Moreover, the influence of some mainstream western male scientists was widely seen in the drawings implying the exposure of limited male scientists to the students. In contrast to this, no real-life female scientists were mentioned by the participants demonstrating limited exposure of female scientists contributing to the gendered attitude toward the scientists. However, some of the findings also challenged the previous findings and depicted scientists with local features, positive expression, and working outdoors. Moreover, participants’ awareness that scientists could be anyone with an inquisitive mind was indicated by the variations in the characters in their drawings. The drawings indicated that scientists could be someone like a mother, themselves, a fashion icon, Buddha, or a crazy-looking person. This study recommends the inclusion of participants’ interviews, and exploration of their textbooks’ depiction of scientists to uncover additional details regarding their understanding of scientists. Also, a critical discussion of the stereotypical attitudes about scientists in class could help challenge the stereotypical assumptions of scientists.

Keywords: scientists, drawings, stereotypes, gender, high school students

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707 Rhizobium leguminosarum: Selecting Strain and Exploring Delivery Systems for White Clover

Authors: Laura Villamizar, David Wright, Claudia Baena, Marie Foxwell, Maureen O'Callaghan

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Leguminous crops can be self-sufficient for their nitrogen requirements when their roots are nodulated with an effective Rhizobium strain and for this reason seed or soil inoculation is practiced worldwide to ensure nodulation and nitrogen fixation in grain and forage legumes. The most widely used method of applying commercially available inoculants is using peat cultures which are coated onto seeds prior to sowing. In general, rhizobia survive well in peat, but some species die rapidly after inoculation onto seeds. The development of improved formulation methodology is essential to achieve extended persistence of rhizobia on seeds, and improved efficacy. Formulations could be solid or liquid. Most popular solid formulations or delivery systems are: wettable powders (WP), water dispersible granules (WG), and granules (DG). Liquid formulation generally are: suspension concentrates (SC) or emulsifiable concentrates (EC). In New Zealand, R. leguminosarum bv. trifolii strain TA1 has been used as a commercial inoculant for white clover over wide areas for many years. Seeds inoculation is carried out by mixing the seeds with inoculated peat, some adherents and lime, but rhizobial populations on stored seeds decline over several weeks due to a number of factors including desiccation and antibacterial compounds produced by the seeds. In order to develop a more stable and suitable delivery system to incorporate rhizobia in pastures, two strains of R. leguminosarum (TA1 and CC275e) and several formulations and processes were explored (peat granules, self-sticky peat for seed coating, emulsions and a powder containing spray dried microcapsules). Emulsions prepared with fresh broth of strain TA1 were very unstable under storage and after seed inoculation. Formulations where inoculated peat was used as the active ingredient were significantly more stable than those prepared with fresh broth. The strain CC275e was more tolerant to stress conditions generated during formulation and seed storage. Peat granules and peat inoculated seeds using strain CC275e maintained an acceptable loading of 108 CFU/g of granules or 105 CFU/g of seeds respectively, during six months of storage at room temperature. Strain CC275e inoculated on peat was also microencapsulated with a natural biopolymer by spray drying and after optimizing operational conditions, microparticles containing 107 CFU/g and a mean particle size between 10 and 30 micrometers were obtained. Survival of rhizobia during storage of the microcapsules is being assessed. The development of a stable product depends on selecting an active ingredient (microorganism), robust enough to tolerate some adverse conditions generated during formulation, storage, and commercialization and after its use in the field. However, the design and development of an adequate formulation, using compatible ingredients, optimization of the formulation process and selecting the appropriate delivery system, is possibly the best tool to overcome the poor survival of rhizobia and provide farmers with better quality inoculants to use.

Keywords: formulation, Rhizobium leguminosarum, storage stability, white clover

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706 Psychosocial Experiences of Black Male Students in Public and Social Spaces on and around a Historically White South African Campus

Authors: Claudia P. Saunderson

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Widening of participation in higher education globally has increased diversity of student populations. However, widening participation is more than mere access. Central to the debate about widening participation are social justice issues of authentic inclusion and appropriate support for success for all students in higher education (HE). Given the recent global campaign for 'Black Lives Matter' as well as the worldwide advocacy for justice in the George Floyd case, the importance of the experiences of Black men, were again poignantly foregrounded. The literature abounds with the negative experiences of Black male students in higher education. Much of this literature emanates from the Global North, with little systematic research on black male students' university experiences originating from the Global South. This research, therefore, explores the psychosocial experiences of Black male students at a historically white South African university. Not only are these students' educational or academic adjustment important, but so is their psychosocial adjustment to the institution. The psychosocial adjustment might include emotional well-being, motivation, as well as the student’s perception of how well he fits in or is made to feel welcome at the institution. The study draws on strands of critical race theory (CRT), co-cultural theory (CCT) as well as defining properties of micro-aggression theory (MAT). In the study, CRT, therefore, served as an overarching theory at the macro level, and it comments on the structural dynamics while MAT and CCT rather focussed on the impact of structural arrangements like racialization, at an individual and micro-level. These theories furthermore provided a coherent analytic framework for this study. Using a case study design, this qualitative study, employing focus groups and individual interviews, drew on the psychosocial experiences of twenty Black male students to explore how they navigate this specific historically white campus. The data were analyzed using thematic analysis that provided a systematic procedure for generating codes and themes from the qualitative data. The study found that the combination of race and gender-based micro-aggressions experienced by students included negative stereotyping, criminalization as well as racial profiling and that these experiences impede participants' ability to thrive at the institution. However, participants also shared positive perspectives about the institution. Some of the positive traits of the institution that the participants mentioned were well-aligned administration, good quality of education, as well as various funding opportunities. This study implies that if any HE institution values transformation, it necessitates the exploration and interrogation of potential aspects that are subtly hidden in the institutional culture and environment that might serve as barriers to the transformation process. This positioning is based on a social justice stance and believes that all students are equal and have the right to racially and culturally equitable and appropriate education and support.

Keywords: critical race theory, higher education transformation, micro-aggression, student experience

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705 Evaluation of Different Cowpea Genotypes Using Grain Yield and Canning Quality Traits

Authors: Magdeline Pakeng Mohlala, R. L. Molatudi, M. A. Mofokeng

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Cowpea (Vigna unguiculata (L.) Walp) is an important annual leguminous crop in semi-arid and tropics. Most of cowpea grain production in South Africa is mainly used for domestic consumption, as seed planting and little or none gets to be used in industrial processing; thus, there is a need to expand the utilization of cowpea through industrial processing. Agronomic traits contribute to the understanding of the association between yield and its component traits to facilitate effective selection for yield improvement. The aim of this study was to evaluate cowpea genotypes using grain yield and canning quality traits. The field experiment was conducted in two locations in Limpopo Province, namely Syferkuil Agricultural Experimental farm and Ga-Molepo village during 2017/2018 growing season and canning took place at ARC-Grain Crops Potchefstroom. The experiment comprised of 100 cowpea genotypes laid out in a Randomized Complete Block Designs (RCBD). The grain yield, yield components, and canning quality traits were analysed using Genstat software. About 62 genotypes were suitable for canning, 38 were not due to their seed coat texture, and water uptake was less than 80% resulting in too soft (mushy) seeds. Grain yield for RV115, 99k-494-6, ITOOK1263, RV111, RV353 and 53 other genotypes recorded high positive association with number of branches, pods per plant, and number of seeds per pod, unshelled weight and shelled weight for Syferkuil than at Ga-Molepo are therefore recommended for canning quality.

Keywords: agronomic traits, canning quality, genotypes, yield

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704 Wear Resistance of 20MnCr5 Steel Nitrided by Plasma

Authors: Okba Belahssen, Said Benramache

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This paper presents wear behavior of the plasma-nitrided 20MnCr5 steel. Untreated and plasma nitrided samples were tested. The morphology was observed by scanning electron microscopy (SEM). The plasma nitriding behaviors of 20MnCr5 steel have been assessed by evaluating tribological properties and surface hardness by using a pin-on-disk wear machine and microhardness tester. Experimental results showed that the nitrides ε-Fe2−3N and γ′-Fe4N present in the white layer improve the wear resistance.

Keywords: plasma-nitriding, alloy 20mncr5, steel, friction, wear

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703 Conformal Coating Technology Applicable to Cell Therapeutics Using Click-Reactive Biocompatible Polymers

Authors: Venkat Garigapati

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Cell-based therapies are limited due to underlying host immune system activity. Microencapsulation of living cells to overcome this issue has some serious drawbacks, such as limitations of nutrient and oxygen diffusion, which pose a threat to the function and longevity of cells. The conformal coating could overcome the issues which are generally involved in traditional microencapsulation. Some of the theoretical advantages of conformal coating include superior nutrient and oxygen supply to cells, prolonged lifespan, improved drug-secreting cell functionality and an opportunity to load high cell doses in small volumes. Despite several advantages to the conformal coating, there are no suitable methods available to apply to living cells. The ultra-thin conformal coating was achieved utilizing click-reactive methacryloyloxyethyl phosphorylcholine (MPC) polymers, which are capable of specifically reacting one polymer to another at neutral pH in the aqueous isotonic system at the desired temperature suitable for living cells without the need of deleterious initiators. ARPE-19 (Adult Retinal Pigment Epithelial cell line-19) cell-spheroids and rat pancreatic islets were used in the formulation studies. The in vitro studies of coated ARPE-19 cell-spheroids and rat islets indicate that the coat was intact; cells were viable and functioning. The in vitro study results revealed that the conformal coating technology seems promising and in vivo studies are being planned.

Keywords: cells, hydrogel, conformal coating, microencapsulation, insulin

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702 Determinants of Hospital Obstetric Unit Closures in the United States 2002-2013: Loss of Hospital Obstetric Care 2002-2013

Authors: Peiyin Hung, Katy Kozhimannil, Michelle Casey, Ira Moscovice

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Background/Objective: The loss of obstetric services has been a pressing concern in urban and rural areas nationwide. This study aims to determine factors that contribute to the loss of obstetric care through closures of a hospital or obstetric unit. Methods: Data from 2002-2013 American Hospital Association annual surveys were used to identify hospitals providing obstetric services. We linked these data to Medicare Healthcare Cost Report Information for hospital financial indicators, the US Census Bureau’s American Community Survey for zip-code level characteristics, and Area Health Resource files for county- level clinician supply measures. A discrete-time multinomial logit model was used to determine contributing factors to obstetric unit or hospital closures. Results: Of 3,551 hospitals providing obstetrics services during 2002-2013, 82% kept units open, 12% stopped providing obstetrics services, and 6% closed down completely. State-level variations existed. Factors that significantly increased hospitals’ probability of obstetric unit closures included lower than 250 annual birth volume (adjusted marginal effects [95% confidence interval]=34.1% [28%, 40%]), closer proximity to another hospital with obstetric services (per 10 miles: -1.5% [-2.4, -0.5%]), being in a county with lower family physician supply (-7.8% [-15.0%, -0.6%), being in a zip code with higher percentage of non-white females (per 10%: 10.2% [2.1%, 18.3%]), and with lower income (per $1,000 income: -0.14% [-0.28%, -0.01%]). Conclusions: Over the past 12 years, loss of obstetric services has disproportionately affected areas served by low-volume urban and rural hospitals, non-white and low-income communities, and counties with fewer family physicians, signaling a need to address maternity care access in these communities.

Keywords: access to care, obstetric care, service line discontinuation, hospital, obstetric unit closures

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701 Evaluation of Natural Frequency of Single and Grouped Helical Piles

Authors: Maryam Shahbazi, Amy B. Cerato

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The importance of a systems’ natural frequency (fn) emerges when the vibration force frequency is equivalent to foundation's fn which causes response amplitude (resonance) that may cause irreversible damage to the structure. Several factors such as pile geometry (e.g., length and diameter), soil density, load magnitude, pile condition, and physical structure affect the fn of a soil-pile system; some of these parameters are evaluated in this study. Although experimental and analytical studies have assessed the fn of a soil-pile system, few have included individual and grouped helical piles. Thus, the current study aims to provide quantitative data on dynamic characteristics of helical pile-soil systems from full-scale shake table tests that will allow engineers to predict more realistic dynamic response under motions with variable frequency ranges. To evaluate the fn of single and grouped helical piles in dry dense sand, full-scale shake table tests were conducted in a laminar box (6.7 m x 3.0 m with 4.6 m high). Two different diameters (8.8 cm and 14 cm) helical piles were embedded in the soil box with corresponding lengths of 3.66m (excluding one pile with length of 3.96) and 4.27m. Different configurations were implemented to evaluate conditions such as fixed and pinned connections. In the group configuration, all four piles with similar geometry were tied together. Simulated real earthquake motions, in addition to white noise, were applied to evaluate the wide range of soil-pile system behavior. The Fast Fourier Transform (FFT) of measured time history responses using installed strain gages and accelerometers were used to evaluate fn. Both time-history records using accelerometer or strain gages were found to be acceptable for calculating fn. In this study, the existence of a pile reduced the fn of the soil slightly. Greater fn occurred on single piles with larger l/d ratios (higher slenderness ratio). Also, regardless of the connection type, the more slender pile group which is obviously surrounded by more soil, yielded higher natural frequencies under white noise, which may be due to exhibiting more passive soil resistance around it. Relatively speaking, within both pile groups, a pinned connection led to a lower fn than a fixed connection (e.g., for the same pile group the fn’s are 5.23Hz and 4.65Hz for fixed and pinned connections, respectively). Generally speaking, a stronger motion causes nonlinear behavior and degrades stiffness which reduces a pile’s fn; even more, reduction occurs in soil with a lower density. Moreover, fn of dense sand under white noise signal was obtained 5.03 which is reduced by 44% when an earthquake with the acceleration of 0.5g was applied. By knowing the factors affecting fn, the designer can effectively match the properties of the soil to a type of pile and structure to attempt to avoid resonance. The quantitative results in this study assist engineers in predicting a probable range of fn for helical pile foundations under potential future earthquake, and machine loading applied forces.

Keywords: helical pile, natural frequency, pile group, shake table, stiffness

Procedia PDF Downloads 106