Mediterranean lichens in the tropics : lichens of the mist oasis of Erkwit, Sudan

From the mist oasis of Erkwit (Red Sea coastal plain of Sudan) 25 epiphytic lichen taxa are reported, probably the first lichen floristic report for the country. Most species encountered are widespread in warm and dry areas worldwide, while a few have their center in the Mediterranean region and document a Mediterranean element in this tropical region

Mechanical performance of reinforced concrete with different proportions and lengths of Basalt Fibres

This paper discusses the effect of the fraction (0.2-0.3% by volume) and length (22 mm and 24 mm) of basalt fibre on the mechanical properties of concrete. The paper aims to evaluate the effect of different combinations of basalt fibres on the mechanical properties of concrete, as well as identify the best basalt fibre length and content that have the optimum influence on concrete. This paper is considered to be distinct from other research work as it fills the literature gap by presenting new unknown facts and also adds new knowledge. For example, it identifies the best basalt fibre length and content combination that demonstrates an improvement in the mechanical properties of concrete. It suggests the use of a blend of 12 mm short and 24 mm long fibres as they have a significant effect on the mechanical properties of concrete, it validates the results obtained from the laboratory by using a statistical analysis of variance ANOVA software, as well as determine the correlation between the mechanical properties of concrete. The results showed that the optimum basalt fibre length and content that enhanced the mechanical properties of concrete is 24 mm long fibre with content of 0.2% by the total volume of concrete. It also show that changing basalt fibre length and content enhance not only both tensile and flexural strengths of concrete, but also reduce its compressive strength, workability and air content of concrete, as well as maintain the unit weight and modulus of elasticity values. In this context, the incorporation of basalt fibres within the mixture becomes an important parameter for strengthening concrete in the construction industry

Evaluation of the Antimicrobial Activity of Four Plant Essential Oils against Some Food and Phytopathogens Isolated from Processed Meat Products in Egypt

Synthetic preservatives are widely utilized by the food industry to inhibit the microbial contamination and increase food safety and shelf life. The excessive utilization of synthetic preservatives can have a negative impact on human health and the environment. There is a great interest to find out natural substances as possible food-preservatives. The consumers' preference for food products with natural ingredients prompted food manufacturers to utilize natural-based preservatives in their production. It is worth noting that plant essential oils (EOs) among the natural-based substances have been efficiently used as antimicrobial agents against phyto- and food pathogens. The current study was conducted to evaluate the microbial contamination of three industrial meat products from five governorates in Egypt, identify the predominant bacterial and fungal isolates and determine the antimicrobial efficacy of some EOs (thyme, fennel, anise and marjoram) against the most predominant microbial isolates. A sensory test was also performed to estimate the customer preferences for specific organoleptic aspects of meat products after EOs treatment. Results showed that there is a promising antimicrobial activity of all studied EOs against some microbial isolates in a dose-dependent manner. In particular, thyme EO showed the highest significant antibacterial activity against P. fluorescence and E. coli. Whereas the marjoram EO showed the highest activity against P. aeruginosa. In addition, the sensory test revealed that the treatment with anise and marjoram EOs showed the highest acceptability by the testers and did not show significant differences on the organoleptic properties with respect to control. As overall, the obtained results of the current research are promising and proved feasibility of employing plant EOs as possible preservatives for processed meat products

Green synthesis of silver nanoparticles (AgNPs) by Lallemantia royleana leaf Extract: Their Bio-Pharmaceutical and catalytic properties

The study of the silver nanoparticles (AgNPs) synthesis based-green methods become more interesting recently due to their low-cost preparation, eco-friendly and non-toxic precursors. The present study approved the ability of the Lallemantia royleana (Benth. in Wall.) Benth. leaf extract for the synthesis of AgNPs for the first time. The synthesized AgNPs were physico-chemical characterized using ultraviolet–visible spectroscopy (UV–Vis), X-ray diffraction (XRD), Fourier Transform-Infrared Spectroscopy (FT-IR), zeta potential and transmission electron microscopy (TEM) analysis. The total phenols, flavonoids, anthocyanin, tannin contents, antioxidant, antimicrobial, anti-inflammatory, anti-arthritic and cytotoxic activities of L. royleana leaf extract and the synthesized AgNPs were investigated. The biocatalytic activity of prepared AgNPs was assessed on methylene blue as a pollutant organic dye. The TEM examination showed that the synthesized AgNPs were predominantly spherical with some mixed shapes and crystalline with average size 34.47 ± 1.6 nm, and showed a localized surface plasmon resonance (LSPR) peak at 425 nm. The zeta potential value was −24.1 mV indicating the stability of produced AgNPs. The new prepared AgNPs have lower total phenols, flavonoids, anthocyanin, tannin contents than L. royleana leaf extract. In addition, the new prepared AgNPs demonstrated the higher DPPH radical scavenging activity (87 %) and the ABTS radical scavenging activity (77 %) at the maximum prepared concentration of 250 μg mL−1 as compared to the L. royleana leaf extract (62 % and 58 %, respectively). The produced AgNPs also exhibited the higher antimicrobial activity against both the Gram-positive (Staphylococcus aureus and Bacillus cereus) and the Gram-negative (Escherichia coli and Shigella flexneri) bacteria and the Candida strains (Candida glabrata and Candida albicans) as compared to the L. royleana leaf extract. The resulting AgNPs indicated a dose-dependent anti-inflammatory effect on human red-blood cell (RBC) membrane stabilization assay and had more activity (72 %) compared to the L. royleana leaf extract (61 %) at 250 µg mL−1. The prepared AgNPs showed promising in vitro anti-arthritic activity evaluated by 73 % compared to 58 % in case of L. royleana leaf extract. The new produced AgNPs showed the higher cytotoxic effect against the human hepatoma (Hep-G2) and the human breast (MCF-7) cancer cells compared to the L. royleana leaf extract with 79.3 % and 77.2 % at 250 µg/mL, respectively. The obtained results revealed also that the green synthesized AgNPs were capable to catalyze MB dye. Therefore, the obtained results provide a promising route of the green synthesis of AgNPs using L. royleana leaf extract with considerable biopharmaceuticals and catalytic applications

Mechanical behaviour of a sprayed concrete lining isolated by a sprayed waterproofing membrane

A waterproofing membrane has an important role in a sprayed concrete lined (SCL) tunnel. In this study, the mechanical behaviour of an SCL with a sprayed waterproofing membrane was investigated by laboratory testing. Two different types of tests were performed to examine the behaviour at different parts of an SCL tunnel linings around a tunnel junction. A four-point bending test was conducted to investigate the behaviour of tunnel linings under a large bending moment, which would represent a section near the opening of a tunnel junction. An eccentric compression test was conducted to investigate the behaviour of tunnel linings under a large compressive axial force (hoop stress) and a relatively small bending moment, which would represent a section at the opposite side of the opening of a tunnel junction. Both test results indicate that an SCL with a sprayed waterproofing membrane behaved as a composite section with very limited slip at the interfaces. Designing the primary lining, the waterproofing membrane and the secondary lining of an SCL tunnel as a composite section could have significant practical implications including time and cost savings.The authors would like to acknowledge the great support offered by technicians at the structural testing laboratory of Ruhr-University-Bochum.This is the accepted manuscript for a paper published in Tunnelling and Underground Space Technology, Volume 47, March 2015, Pages 143–152, doi:10.1016/j.tust.2015.01.00

Nonlinear finite element modelling and parametric study of CFRP shear-strengthened prestressed concrete girders

This paper presents a three-dimensional nonlinear finite element (FE) model for prestressed concrete girders strengthened in shear with externally bonded carbon fibre reinforced polymer (CFRP) reinforcement. A total strain rotating crack model, where the crack direction changes with the change in the direction of the principal tensile stress, was used for the concrete. In this model, explicit modelling of the concrete shear behaviour after cracking, e.g. via a shear retention parameter, is not required as the crack plane is always a principal plane with no shear stresses. The FE model was validated using experimental results from the literature. An extensive parametric study was carried out to identify the effect of the concrete compressive strength, CFRP width-to-spacing ratio, CFRP thickness, girder effective depth, shear span to effective depth ratio, level of prestress, tendon profile, pre-cracking and CFRP-to-concrete interface model on the predicted shear force capacity. The results suggested that the predicted shear strength enhancement can be significant and increases with the increase in concrete compressive strength, CFRP width-to-spacing ratio, and CFRP thickness but decreases with the increase in girder effective depth and shear span to effective depth ratio.The first author gratefully acknowledges the financial support of KRG.This is the accepted manuscript. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S0950061814012872

Организация научно-исследовательской работы студентов на кафедре акушерства и гинекологии

ПРЕПОДАВАТЕЛЬСКИЙ СОСТАВ МЕДИЦИНСКИХ УЧЕБНЫХ УЧРЕЖДЕНИЙнаучно-исследовательская работаАКУШЕРСТВО /обучГИНЕКОЛОГИЯ /обучСТУДЕНТЫ МЕДИЦИНСКИХ УЧЕБНЫХ ЗАВЕДЕНИ

CFRP shear strengthening of reinforced-concrete T-beams with corroded shear links

This paper investigates the structural behavior of uncorroded as well as corroded RC T-beams strengthened in shear with either externally bonded (EB) carbon fiber–reinforced polymer (CFRP) sheets or embedded CFRP rods. Nine tests were carried out on RC T-beams having an effective depth of 295 mm and a shear span to effective depth ratio of 3.05. The investigated parameters are the shear link corrosion level (uncorroded, 7% corroded, or 12% corroded) and type of CFRP strengthening system (EB CFRP sheets or embedded CFRP rods). The unstrengthened beams with shear link corrosion levels of 7 and 12% had shear strengths that were 11 and 14%, respectively, less than the shear strength of the uncorroded unstrengthened beam. Both the embedded CFRP rods and EB CFRP sheets were effective in enhancing the shear strength of tested beams but the effectiveness of both strengthening systems decreased with increasing shear link corrosion level. The shear strength enhancement provided by the embedded CFRP rods and EB CFRP sheets decreased from 19 and 15%, respectively, to 12 and 11%, respectively, with an increase in shear link corrosion level from 7 to 12%. Corrosion of the shear links did not have a significant effect on the beam stiffness. Premature debonding limited the effectiveness of the EB CFRP sheets whereas the embedded CFRP rods did not exhibit signs of debonding and therefore showed higher effectiveness.The authors would like to thank Fyfe Europe for supplying the CFRP sheets and epoxy laminating resin used in this study. The first author acknowledges the financial support of the UK Engineering and Physical Sciences Research Council.This is the author accepted manuscript. The final version is available from American Society of Civil Engineers via http://dx.doi.org/10.1061/(ASCE)CC.1943-5614.000054

The synthesis of data from instrumented structures and physics-based models via Gaussian processes

At the heart of structural engineering research is the use of data obtained from physical structures such as bridges, viaducts and buildings. These data can represent how the structure responds to various stimuli over time when in operation. Many models have been proposed in literature to represent such data, such as linear statistical models. Based upon these models, the health of the structure is reasoned about, e.g. through damage indices, changes in likelihood and statistical parameter estimates. On the other hand, physics-based models are typically used when designing structures to predict how the structure will respond to operational stimuli. These models represent how the structure responds to stimuli under idealised conditions. What remains unclear in the literature is how to combine the observed data with information from the idealised physics-based model into a model that describes the responses of the operational structure. This paper introduces a new approach which fuses together observed data from a physical structure during operation and information from a mathematical model. The observed data are combined with data simulated from the physics-based model using a multi-output Gaussian process formulation. The novelty of this method is how the information from observed data and the physics-based model is balanced to obtain a representative model of the structures response to stimuli. We present our method using data obtained from a fibre-optic sensor network installed on experimental railway sleepers. The curvature of the sleeper at sensor and also non-sensor locations is modelled, guided by the mathematical representation. We discuss how this approach can be used to reason about changes in the structures behaviour over time using simulations and experimental data. The results show that the methodology can accurately detect such changes. They also indicate that the methodology can infer information about changes in the parameters within the physics-based model, including those governing components of the structure not measured directly by sensors such as the ballast foundation.This work was supported by The Alan Turing Institute under the EPSRC grant EP/N510129/1 and the Turing-Lloyd's Register Foundation Programme for Data-Centric Engineering. The authors would also like to acknowledge EPSRC (grant nos. EP/P020720/1, EP/R018413/1, EP/R034710/1, EP/R004889/1) and Innovate UK (grant no. 920035) for funding this research through the Centre for Smart Infrastructure and Construction (CSIC) Innovation and Knowledge Centre. Research related to installation of the sensor system was carried out under EPSRC grant no. EP/N021614. Mark Girolami is supported by a Royal Academy of Engineering Research Chair in Data Centric Engineering

Pulmonary Hypertension in Patients with Treated Pulmonary Tuberculosis: Analysis of 14 Consecutive Cases

Background Pulmonary tuberculosis (PTB) is an increasing global health problem that continues to cause significant morbidity and mortality. The impact of PTB has been measured in terms morbidity and mortality and little attention has been paid to continuing respiratory disability in those who were cured. Pulmonary hypertension (PHT) is a serious respiratory disability that results from structural lung damage and chronic hypoxia. This study was conducted to investigate the presence of PHT in a cohort of treated PTB patients who presented with shortness of breath. Methods This is a cross-sectional study that included 14 consecutive patients who were cured of PTB and presented with shortness of breath. Demographic and clinical data were recorded for all patients. PHT was diagnosed using Doppler echocardiography. Results Fourteen patients who were treated for PTB and were found to have PHT were studied. All patients were sputum smear negative at the time of the study. The mean age (SD) was 43.1 (13.6) and half of the patients were males. The mean number of years since PTB was diagnosed (SD) was 9.4 (10.9). All patients had abnormal chest x-rays. The commonest radiological abnormality was fibrocavitation which occurred in 50% of patients. Estimated pulmonary artery systolic pressure (PASP) of 51 to 80 mm/Hg was found in 9 patients (64.3%) whereas PASP of 40 to 50 mm/Hg was found in 4 patients (28.6%) and one patient had PASP more than 80 mm/Hg. Conclusions Different grades of PHT occurred in this cohort of treated PTB patients on average about 9 years after cure. The findings of this study support implementation of strategies for early detection and prevention of PTB. For those who were cured from PTB, longer periods of disability should be implemented in assessment of disease burden