Service load analysis of unbonded partially prestressed concrete members

In the design of unbonded partially prestressed concrete (UPPC) members, it is necessary to estimate the stresses in steel and concrete in order to satisfy the requirements of the serviceability limit state. A numerical method has been developed to predict the response of UPPC beams under service load, and the results agree well with experimental results reported in the technical literature. A parametric study has been undertaken to evaluate the variation of stress in prestressed steel under service load as well as the ratio of length of equivalent deformation region to the neutral axis depth at critical section. Results show that this ratio is not sensitive to the variation of the combined reinforcement index. From the moment of application of load to the cracking of the beam, and until the yielding of non-prestressed steel, this ratio is fairly stable and it can be taken as a constant. With the determination of this ratio, an approximate cubic equation similar to that used for cracked section analysis of bonded partially prestressed members is established. Predictions of stresses under service load are in good agreement with available test data. © 2005 Thomas Telford Ltd.published_or_final_versio

Three-dimensional vibration analysis of a torus with circular cross section

The free vibration characteristics of a torus with a circular cross section are studied by using the three-dimensional, small-strain, elasticity theory. A set of three-dimensional orthogonal coordinates system, comprising the polar coordinate (r, θ) at each circular cross section and the circumferential coordinate φ around the ring, is developed. Each of the displacement components ur, vτ, and wφ in the r, θ, and φ directions, respectively, is taken as a product of the Chebyshev polynomials in the r direction and the trigonometric functions in the θ and φ directions. Eigenfrequencies and vibration mode shapes have been obtained via a three-dimensional displacement-based extremum energy principle. Upper bound convergence of the first seven eigenfrequencies accurate to at least six significant figures is obtained by using only a few terms of the admissible functions. The eigenfrequency responses due to variation of the ratio of the radius of the ring centroidal axis to the cross-sectional radius are investigated in detail. Very accurate eigenfrequencies and deformed mode shapes of the three-dimensional vibration are presented. All major modes such as flexural thickness-shear modes, in-plane stretching modes, and torsional modes are included in the analysis. The results may serve as a benchmark reference for validating other computational techniques for the problem. © 2002 Acoustical Society of America.published_or_final_versio

Three-dimensional vibration analysis of prisms with isosceles triangular cross-section

This paper studies the three-dimensional (3-D) free vibration of uniform prisms with isosceles triangular cross-section, based on the exact, linear and small strain elasticity theory. The actual triangular prismatic domain is first mapped onto a basic cubic domain. Then the Ritz method is applied to derive the eigenfrequency equation from the energy functional of the prism. A set of triplicate Chebyshev polynomial series, multiplied by a boundary function chosen to, a priori, satisfy the geometric boundary conditions of the prism is developed as the admissible functions of each displacement component. The convergence and comparison study demonstrates the high accuracy and numerical robustness of the present method. The effect of length-thickness ratio and apex angle on eigenfrequencies of the prisms is studied in detail and the results are compared with those obtained from the classical one-dimensional theory and the 3-D finite element method. Sets of valuable data known for the first time are reported, which can serve as benchmark values in applying various approximate beam and rod theories. © 2009 Springer-Verlag.published_or_final_versionSpringer Open Choice, 01 Dec 201

Economic analysis of Senegalia senegal (Gum Arabic) production in Yobe state, Nigeria

This work analyzed the economics of Senegalia senegal (gum Arabic) production in Yobe state, Nigeria. Specifically, it studied the socioeconomic characteristic of the farming respondents and the profitability of gum Arabic production in the state. Purposive and random sampling techniques were used to select Afunori, Nangere and Damaturu plantation areas as well as the sampled gum Arabic farmers respectively. Yero Yemeni`s model was used in the determination of the number of gum Arabic farmers involved in the study. Data was collected using a structured questionnaire and the variables on which data was collected included gum Arabic production inputs and output, marketing costs and revenues. Data was also collected on socioeconomic variables. Both financial and statistical tools were used in analyzing the data including Gross Margin (GM) and Profitability analyses. Socioeconomic data revealed that the gum Arabic production scenario was dominated by youth, the male gender, educated elites and public servants with small land holding. Financial results on the contrary, revealed US$805.86 (N241, 758.00) GM values per hectare per year, whereas US$ 345, 948.88 (N103, 784, 664.00) was the total net profit realized. On the average each respondent earned US$1, 572.49 (N 471, 747.00). Thus, it was concluded that gum Arabic production in the state was economically profitable. However, its resources were grossly under exploited. Other production constraints uncovered included land tenure problem, poor extension services, lack of improved planting stocks and poor support on the part of government. Creation of enabling environment for improved production and marketing as well as adequate stakeholder involvement were some of the major policy recommendations made. Keywords: Economic analysis, Senegalia senegal, production, Yobe Stat

Economic analysis of Neem (Azadirachta indica) production in Yobe state, Nigeria

This work determined the economics of Azadirachta indica (neem) production in Yobe State, Nigeria. Specifically, it studied the socioeconomic characteristic of the farming respondents and the profitability of neem production in the State. Multistage sampling technique was used to select Afunori, Nangere and Damaturu plantation areas as well as the sampled neem farmers respectively. Yero Yemeni`s model was used in the determination of the number of neem farmers involved in the study. Data was collected using a structured questionnaire and the variables on which data was collected included neem production inputs and output, marketing costs and revenues. Data was also collected on socioeconomic variables. Both descriptive statistics and economic tools were used in analyzing the data including percentages, frequency distribution tables and Gross Margin (GM) analyses. Socioeconomic data revealed that aged, male gender, individuals with no formal education as well those with small land holding constituted 50%, 95.45%, 54.55% and 90.91% respectively. Financial results revealed respective GM and net profit values of N3, 831.82 and N 3, 274.06 per hectare per year. Thus, it was concluded that neem production in the State was not economically viable and was attributed principally to ignorance of its economic potentials and lack of functional markets. Other production constraints uncovered included land tenure problem, poor extension services, lack of improved planting stocks and poor supportive services. Key words: Economic analysis, Azadirachta indica, productio

Use of ultraviolet-light irradiated multiple myeloma cells as immunogens to generate tumor-specific cytolytic T lymphocytes

10.1186/1476-8518-6-2Journal of Immune Based Therapies and Vaccines6

Cobalt chloride pretreatment promotes cardiac differentiation of human embryonic stem cells under atmospheric oxygen level

Our previous study demonstrated the direct involvement of the HIF-1α subunit in the promotion of cardiac differentiation of murine embryonic stem cells (ESCs). We report the use of cobalt chloride to induce HIF-1α stabilization in human ESCs to promote cardiac differentiation. Treatment of undifferentiated hES2 human ESCs with 50μM cobalt chloride markedly increased protein levels of the HIF-1α subunit, and was associated with increased expression of early cardiac specific transcription factors and cardiotrophic factors including NK2.5, vascular endothelial growth factor, and cardiotrophin-1. When pretreated cells were subjected to cardiac differentiation, a notable increase in the occurrence of beating embryoid bodies and sarcomeric actinin-positive cells was observed, along with increased expression of the cardiac-specific markers, MHC-A, MHC-B, and MLC2V. Electrophysiological study revealed increased atrial-and nodal-like cells in the cobalt chloride-pretreated group. Confocal calcium imaging analysis indicated that the maximum upstroke and decay velocities were significantly increased in both noncaffeine and caffeine-induced calcium transient in cardiomyocytes derived from the cobalt chloride-pretreated cells, suggesting these cells were functionally more mature. In conclusion, our study demonstrated that cobalt chloride pretreatment of hES2 human ESCs promotes cardiac differentiation and the maturation of calcium homeostasis of cardiomyocytes derived from ESCs. © 2011 Mary Ann Liebert, Inc.published_or_final_versio

Lysosomal membrane permeabilization is involved in oxidative stress-induced apoptotic cell death in LAMP2-deficient iPSCs-derived cerebral cortical neurons

postprin

Linking cohort-based data with electronic health records: a proof-of-concept methodological study in Hong Kong.

OBJECTIVES: Data linkage of cohort-based data and electronic health records (EHRs) has been practised in many countries, but in Hong Kong there is still a lack of such research. To expand the use of multisource data, we aimed to identify a feasible way of linking two cohorts with EHRs in Hong Kong. METHODS: Participants in the 'Children of 1997' birth cohort and the Chinese Early Development Instrument (CEDI) cohort were separated into several batches. The Hong Kong Identity Card Numbers (HKIDs) of each batch were then uploaded to the Hong Kong Clinical Data Analysis and Reporting System (CDARS) to retrieve EHRs. Within the same batch, each participant has a unique combination of date of birth and sex which can then be used for exact matching, as no HKID will be returned from CDARS. Raw data collected for the two cohorts were checked for the mismatched cases. After the matching, we conducted a simple descriptive analysis of attention deficit hyperactivity disorder (ADHD) information collected in the CEDI cohort via the Strengths and Weaknesses of ADHD Symptoms and Normal Behaviour Scale (SWAN) and EHRs. RESULTS: In total, 3473 and 910 HKIDs in the birth cohort and CEDI cohort were separated into 44 and 5 batches, respectively, and then submitted to the CDARS, with 100% and 97% being valid HKIDs respectively. The match rates were confirmed to be 100% and 99.75% after checking the cohort data. From our illustration using the ADHD information in the CEDI cohort, 36 (4.47%) individuals had ADHD-Combined score over the clinical cut-off in the SWAN survey, and 68 (8.31%) individuals had ADHD records in EHRs. CONCLUSIONS: Using date of birth and sex as identifiable variables, we were able to link the cohort data and EHRs with high match rates. This method will assist in the generation of databases for future multidisciplinary research using both cohort data and EHRs

Difference in the color stability of direct and indirect resin composites

Indirect resin composites are generally regarded to have better color stability than direct resin composites since they possess higher conversion degree. OBJECTIVE: The present study aimed at comparing the changes in color (&#916;E) and color coordinates (&#916;L, &#916;a and &#916;b) of one direct (Estelite Sigma: 16 shades) and 2 indirect resin composites (BelleGlass NG: 16 shades; Sinfony: 26 shades) after thermocycling. MATERIAL AND METHODS: Resins were packed into a mold and light cured; post-curing was performed on indirect resins. Changes in color and color coordinates of 1-mm-thick specimens were determined after 5,000 cycles of thermocycling on a spectrophotometer. RESULTS: &#916;E values were in the range of 0.3 to 1.2 units for direct resins, and 0.3 to 1.5 units for indirect resins, which were clinically acceptable (&#916;E0.05), while &#916;L, &#916;a and &#916;b values were signifcantly different by the type of resins (p<0.05). For indirect resins, &#916;E values were infuenced by the brand, shade group and shade designation based on three-way ANOVA (p<0.05). CONCLUSION: Direct and indirect resin composites showed similar color stability after 5,000 cycles of thermocycling; however, their changes in the color coordinates were different