Investigation of Self-Healing Mortars with and without Bagasse Ash at Pre- and Post-Crack Times

Cracks in typical mortar constructions enhance water permeability and degrade ions into the structure, resulting in decreased mortar durability and strength. In this study, mortar samples are created that self-healed their cracks by precipitating calcium carbonate into them. Bacillus subtilus bacterium (10⁻⁷, 10⁻⁹ cells/mL), calcium lactate, fine aggregate, OPC-cement, water, and bagasse ash were used to make self-healing mortar samples. Calcium lactates were prepared from discarded eggshells and lactic acid to reduce the cost of self-healing mortars, and 5% control burnt bagasse ash was also employed as an OPC-cement alternative. In the presence of moisture, the bacterial spores in mortars become active and begin to feed the nutrient (calcium lactate). The calcium carbonate precipitates and plugs the fracture. Our experimental results demonstrated that cracks in self-healing mortars containing bagasse ash were largely healed after 3 days of curing, but this did not occur in conventional mortar samples. Cracks up to 0.6 mm in self-healing mortars were filled with calcite using 10⁻⁷ and 10⁻⁹ cell/mL bacteria concentrations. Images from an optical microscope, X-ray Diffraction (XRD), and a scanning electron microscope (SEM) were used to confirm the production of calcite in fractures. Furthermore, throughout the pre- and post-crack-development stages, self-healing mortars have higher compressive strength than conventional mortars. The precipitated calcium carbonates were primed to compact the samples by filling the void spaces in hardened mortar samples. When fissures developed in hardened mortars, bacteria became active in the presence of moisture, causing calcite to precipitate and fill the cracks. The compressive strength and flexural strength of self-healing mortar samples are higher than conventional mortars before cracks develop in the samples. After the healing process of the broken mortar parts (due to cracking), self-healing mortars containing 5% bagasse ash withstand a certain load and have greater flexural strength (100 kPa) than conventional mortars (zero kPa) at 28 days of cure. Self-healing mortars absorb less water than typical mortar samples. Mortar samples containing 10⁻⁷ bacteria cells/mL exhibit greater compressive strength, flexural strength, and self-healing ability. XRD and SEM were used to analyze mortar samples with healed fractures. XRD, FTIR, and SEM images were also used to validate the produced calcium lactate. Furthermore, the durability of mortars was evaluated using DTA-TGA analysis and water absorption tests.     

Halichondramine,a new tetracyclic bipiperidine alkaloid from the marine sponge Halichondria sp

Halichondramine (1), a new tetracyclic alkylbipiperidine alkaloid, has been isolated from the marine sponge Halichondria sp., collected in the Dahlak archipelago (the Red Sea), Eritrea. The structure of halichondramine was elucidated by interpretation of MS, COSY, HMQC, HMBC, TOCSY, and HSQC-TOCSY data.     

Influence of the endothelium on tone and the response of isolated pig coronary artery to norepinephrine

The influence of the endothelium on smooth muscle tone and the response of the pig right coronary artery to norepinephrine (NE) was studied. Isolated rings of artery with and without endothelium were stretched in the presence of nitroprusside to a tension previously determined to be optimal for contraction. During wash out of the nitroprusside, rings without endothelium spontaneously generated tone representing 24% of the contraction caused by potassium (120 mM); in rings with endothelium no significant spontaneous tone was observed. Relaxations were caused by NE in rings with endothelium contracted with prostaglandin F2 alpha (PGF2 alpha). In rings without endothelium, NE relaxed spontaneously generated tone as well as that produced by PGF2 alpha. Independent of the mode or degree of contraction, rings with endothelium were more sensitive to NE than rings without endothelium. The difference in sensitivity to NE between rings with and without endothelium was likely due to endothelial cell alpha-2 adrenoceptors, inasmuch as the difference was abolished by rauwolscine. In the presence of propranolol and prazosin, endothelium-dependent relaxations were observed which were also inhibited by rauwolscine. Nevertheless, beta adrenoceptors are the predominant mediator of the relaxation to NE of pig coronary smooth muscle, because propranolol caused a greater shift to the right of the relaxation induced by NE compared to that caused by endothelium removal. Accordingly, under resting conditions, NE caused contractions only in the presence of propranolol. These contractions were attenuated by prazosin or rauwolscine, but blocked only by a combination of both alpha adrenoceptor antagonists.(ABSTRACT TRUNCATED AT 250 WORDS)     

Integrating family planning into Ethiopian voluntary testing and counselling programmes

Problem

Governments and donors encourage the integration of family planning into voluntary testing and counselling (VCT) services. We aimed to determine if clients of VCT services have a need for and will accept quality family planning services.

Approach

“Voluntary HIV counselling and testing integrated with contraceptive services” is a proof-of-concept study that interviewed 4019 VCT clients before the addition of family planning services and 4027 different clients after family planning services were introduced. Clients attended eight public VCT facilities in the Oromia region, Ethiopia. The intervention had four components: development of family planning counselling messages for VCT clients, VCT provider training, contraceptive supply provision and monitoring.

Local setting

Ethiopia’s population of 80 million is increasing rapidly at an annual rate of 2.5%. Contraceptive prevalence is only 15%. The estimated adult HIV prevalence rate is 2.1%, with more than 1.1 million people infected. The number of VCT facilities increased from 23 in 2001 to more than 1000 in 2007, and the number of HIV tests taken doubled from 1.7 million tests in 2007 to 3.5 million in 2008.

Relevant changes

Clients interviewed after the introduction of family planning services received significantly more family planning counselling and accepted significantly more contraceptives than those clients served before the intervention. However, three-quarters of the clients were not sexually active. Of those clients who were sexually active, 70% were using contraceptives.

Lessons learned

The study demonstrated that family planning can be integrated into VCT clinics. However, policy-makers and programme managers should carefully consider the characteristics and reproductive health needs of target populations when making decisions about service integration.     

Beta 1- and beta 2-adrenoceptor antagonist activities of ICI-215001, a putative beta 3-adrenoceptor agonist.

1. The present study was undertaken to characterize the beta 3-adrenoceptor agonist activity of ICI-215001 and to determine whether it exhibits additional activities on beta 1- and beta 2-adrenoceptors in isolated spontaneously beating atrium, trachea and ileum of guinea-pig. 2. In guinea-pig atrium, isoprenaline, a non-selective beta-adrenoceptor agonist, caused concentration-dependent, positive chronotropic effects that were inhibited by atenolol, a selective beta 1-antagonist. ICI-215001 also competitively antagonized the increase in heart rate caused by isoprenaline. 3. ICI-215001 exhibited low intrinsic activity at increasing the beating rate of atrium and no activity on resting or induced tone of tracheal strips. 4. In strips of guinea-pig trachea, contracted submaximally with carbachol, isoprenaline, caused concentration-dependent relaxations. Both ICI-118551, a selective beta 2-adrenoceptor antagonist, and ICI-215001 competitively inhibited the relaxations caused by isoprenaline. 5. In isolated strips of guinea-pig ileum longitudinal smooth muscle contracted with histamine, isoprenaline and ICI-215001 caused relaxations which were inhibited by alprenolol, a beta-adrenoceptor antagonist with modest affinity for beta 3-adrenoceptors, but were resistant to ICI-118551 and atenolol. 6. These results indicate that ICI-215001 exhibits beta 3-adrenoceptor agonist activity as demonstrated by relaxations mediated via atypical beta-adrenoceptors in the longitudinal smooth muscle of guinea-pig ileum. Further, the studies demonstrate that ICI-215001 can act as an antagonist at beta 1- and beta 2-adrenoceptors in situations where its intrinsic agonist activity is low.     

Conducting a multidisciplinary morbidity and mortality conference in the trauma-surgical intensive care unit

The trauma-surgical intensive care unit at Harborview Medical Center has developed a multidisciplinary case review process to allow discussion of complications and issues in an open forum among multiple services. Conducted monthly, this meeting provides a forum for clear communication between members of the patient care team with the goal of developing best practices, system changes, and policies that will minimize risk for the patients and provide education for the staff.     

Tetanus in a rural Ethiopian hospital

Despite the widespread availability of a safe and effective vaccine, tetanus continues to be a significant public health problem in the developing countries.     

Endothelial Repair and Regeneration Following Intimal Injury

Coronary artery intervention using device implants significantly reduce the risk of restenosis and the need for revascularization but are associated with endothelial denudation and impaired function. This may be due to incomplete endothelial recovery as a result of intimal injury, presence of polymer and/or high antiproliferative drug accumulation in the intima. The permanent presence of a metal prosthesis or polymer may impair the proliferation of resident endothelial cells to cover empty areas. Attention has focused on the robust replenishment of endothelial monolayer by recruitment of circulating endothelial progenitor cells derived from the bone marrow to areas of endothelial injury. The balance between endothelial damage and repair is critical for the maintenance of intimal integrity, function, and prevention of thrombotic complications. This review will discuss on the aftereffects of intravascular device implants on endothelial injury and the pathways involved in endothelial repair and regeneration with an emphasis on endothelial progenitor cells.