Civil Engineering Materials

Civil Engineering Materials prepares you for today’s engineering challenges, providing a broad overview of the materials you will use in your studies and career. You are not only introduced to traditional materials, such as concrete, steel, timber, and soils, but you also explore important non-traditional materials, such as synthetics and industrial-by products. The authors use a wealth of practical examples and straight-forward explanations to ensure you gain a full understanding of the characteristics and behavior of various materials, how they interact, and how to best utilize and combine traditional and non-traditional materials. While emphasizing the effective use of civil engineering materials, the authors carefully consider sustainability to give you a broader context of how materials are current used in contemporary applications

Effects of suppression of bone turnover on cortical and trabecular load sharing in the canine vertebral body

The relative biomechanical effects of antiresorptive treatment on cortical thickness vs. trabecular bone microarchitecture in the spine are not well understood. To address this, T-10 vertebral bodies were analyzed from skeletally mature female beagle dogs that had been treated with oral saline (n=8 control) or a high dose of oral risedronate (0.5 mg/kg/day, n=9 RIS-suppressed) for 1 year. Two linearly elastic finite element models (36-μm voxel size) were generated for each vertebral body—a whole-vertebra model and a trabecular-compartment model—and subjected to uniform compressive loading. Tissue-level material properties were kept constant to isolate the effects of changes in microstructure alone. Suppression of bone turnover resulted in increased stiffness of the whole vertebra (20.9%, p=0.02) and the trabecular compartment (26.0%, p=0.01), while the computed stiffness of the cortical shell (difference between whole-vertebra and trabecular-compartment stiffnesses, 11.7%, p=0.15) was statistically unaltered. Regression analyses indicated subtle but significant changes in the relative structural roles of the cortical shell and the trabecular compartment. Despite higher average cortical shell thickness in RIS-suppressed vertebrae (23.1%, p=0.002), the maximum load taken by the shell for a given value of shell mass fraction was lower (p=0.005) for the RIS-suppressed group. Taken together, our results suggest that—in this canine model—the overall changes in the compressive stiffness of the vertebral body due to suppression of bone turnover were attributable more to the changes in the trabecular compartment than in the cortical shell. Such biomechanical studies provide an unique insight into higher-scale effects such as the biomechanical responses of the whole vertebra

Perceptions on epilepsy stigma among attendants of patients other than epilepsy

Background: Stigma is an important contributor for epilepsy. In India, most studies on epilepsy stigma were carried out using knowledge, attitude, and practice questionnaires. Of the four studies which used stigma scale, only three studies investigated up to 50 healthy subjects and were of eastern and western-central India; however, representation is lacking from south India. Perceptions on stigma vary by region and cultural group. Aim: To study the perceptions among attendants of patients other epilepsy. Materials and Methods: In a prospective observational study, 170 healthy attendants of patients other than epilepsy belonging to south India were recruited and their perceptions on epilepsy stigma were documented. Results: Mean age of the subjects was 34.39 ± 11.49 years. The mean score of epilepsy stigma was 20.06 ± 13.66. Majority of the subjects had mild epilepsy stigma perception (83.6%). No significant difference in epilepsy stigma score was observed with respect to gender, age groups, religion, and marital status. Higher epilepsy stigma score was observed in rural, less educated, and low income groups. In regression analysis, family income (standardized beta = −0.201, P < 0.01) and occupation (standardized beta = −0.174, P < 0.05) were found to be the significant predictors of epilepsy stigma. Conclusions: The results suggest that, to reduce the stigma of epilepsy among the public, socioeconomic and educationally disadvantaged groups should be given priority for destigmatization campaigns

Technology Assessment of Laser-Assisted Materials Processing in Space

Lasers are useful for performing operations such as joining, machining, built-up freeform fabrication, shock processing, and surface treatments. These attributes are attractive for the supportability of longer-term missions in space due to the multi-functionality of a single tool and the variety of materials that can be processed. However, current laser technology also has drawbacks for space-based applications, specifically size, power efficiency, lack of robustness, and problems processing highly reflective materials. A review of recent laser developments will be used to show how these issues may be reduced and indicate where further improvement is necessary to realize a laser-based materials processing capability in space. The broad utility of laser beams in synthesizing various classes of engineering materials will be illustrated using state-of-the art processing maps for select lightweight alloys typically found on spacecraft. With the advent of recent breakthroughs in diode-pumped solid-state lasers and fiber optic technologies, the potential to perform multiple processing techniques is increasing significantly. Lasers with suitable wavelengths and beam properties have tremendous potential for supporting future space missions to the moon, Mars and beyond

Prevalence of lower urinary tract symptoms in patients of benign prostatic hyperplasia attending Tertiary Care Hospital in the State of Andhra Pradesh

Background: There are only few studies available on the prevalence of lower urinary tract symptoms (LUTS) evaluated by the international prostate symptom score tool (IPSS), and it has not been validated in the Indian population. Aim: The purpose of the present study was to determine the prevalence of lower urinary tract symptoms in patients of benign prostatic hyperplasia (BPH) and to validate the IPSS tool in our studied population. Materials and Methods: One hundred BPH aged >51 years attending the outpatient department of Urology were recruited for the study. LUTS were evaluated using the international IPSS. The IPSS was validated for reliability and reproducibility by Cronbach's alpha and intraclass correlation coefficient (ICC). Results: The coefficients of Cronbach's alpha and ICC were 0.80 and 0.86, respectively. The majority of patients had moderate symptoms (72%) followed by severe symptoms (17%). Severity of symptoms increased with age (P < 0.01). The total score was associated with age (P < 0.01). The majority of patients (12%) with the severity of symptoms had reported that symptoms bother them to some extent. Conclusion: The results of the study showed that IPSS could serve as a good instrument to assess LUTS in this population

Synthesis and evaluation of stilbene and dihydrostilbene derivatives as potential anticancer agents that inhibit tubulin polymerization

An array of cis-, trans-, and dihydrostilbenes and some N-arylbenzylamines were synthesized and evaluated for their cytotoxicity in the five cancer cell cultures A-549 lung carcinoma, MCF-7 breast carcinoma, HT-29 colon adenocarcinoma, SKMEL-5 melanoma, and MLM melanoma. Several cis-stilbenes, structurally similar to combretastatins, were highly cytotoxic in all five cell lines and these were also found to be active as inhibitors of tubulin polymerization. The most active compounds also inhibited the binding of colchicine to tubulin. The most potent of the new compounds, both as a tubulin polymerization inhibitor and as a cytotoxic agent, was (Z)-1-(4-methoxyphenyl)-2-(3,4,5-trimethoxyphenyl)ethene (5a). This substance was almost as potent as combretastatin A-4 (1a), the most active of the combretastatins, as a tubulin polymerization inhibitor. Compound 5a was found to be approximately 140 times more cytotoxic against HT-29 colon adenocarcinoma cells and about 10 times more cytotoxic against MCF-7 breast carcinoma cells than combretastatin A-4. However, 5a was found to be about 20 times less cytotoxic against A-549 lung carcinoma cells, 30 times less cytotoxic against SKMEL-5 melanoma cells, and 7 times less cytotoxic against MLM melanoma cells than combretastatin A-4. The relative potencies 5a greater than 8a greater than 6a for the cis, dihydro, and trans compounds, respectively, as inhibitors of tubulin polymerization are in agreement with the relative potencies previously observed for combretastatin A-4 (1a), dihydrocombretastatin A-4 (1c), and trans-combretastatin A-4 (1b). The relative potencies 5a greater than 8a greater than 6a were also reflected in the results of the cytotoxicity assays. Structure-activity relationships of this group of compounds are also discussed