The Use of Ground Coal Bottom Ash/Slag as a Cement Replacement for Sustainable Concrete Infrastructure.

Cement production requires considerable energy and natural resources, severely impacting the environment due to harmful gas emissions. Coal bottom ash (CBA) and coal boiler slag (CBS), byproducts of coal-fired powerplants having pozzolanic properties, can be mechanically ground and replace cement in concrete, which reduces waste in landfills, preserves natural resources, and reduces health hazards. This study was performed to determine the optimum cement replacement amount of ground CBA (GCBA) and ground CBS (GCBS) in concrete, which was 10% for GCBA and 5% for GCBS. GCBA-based concrete exhibited superior tensile strength, modulus of elasticity, and durability compared to the control. In the Rapid Chloride Penetration Test, 10% GCBA concrete resulted in 2026 coulombs at 56 days, compared to 3405 coulombs for the control, indicating more resistance to chloride penetration. Incorporating 2.5% nanoclay in GCBA-based concrete increased the optimum GCBA content by 5%, and the compressive strength of 15% GCBA concrete increased by 4 MPa. The mortar consisting of the finest GCBA(L1) having Blaine fineness of 3072 g/cm2 yielded the highest compressive strength (32.7 MPa). The study discovered that the compressive strength of GCBA and GCBS-based mortars increases with fineness, and meeting the recommended fineness limit in ASTM C618 enhances concrete or mortar properties.

The yield of a tuberculosis household contact investigation in two regions of Ethiopia.

SETTING: Amhara and Oromia regions, Ethiopia. OBJECTIVE: To determine the yield of a household contact investigation for tuberculosis (TB) under routine programme conditions. DESIGN: Between April 2013 and March 2014, TB clinic officers conducted symptom-based screening for household contacts (HHCs) of 6015 smear-positive TB (SS+ TB) index cases. Based on quarterly reported programme data, we calculated the yield in terms of number needed to screen (NNS) and number needed to test (NNT). RESULTS: Of 15,527 HHCs screened, 6.1% had presumptive TB (8.5% in Oromia vs. 3.9% in Amhara). All forms of TB and SS+ TB were diagnosed in respectively 2.5% (Oromia 3.9% vs. Amhara 1.2%) and 0.76% (Oromia 0.98% vs. Amhara 0.55%) of contacts. The NNS to detect a TB case all forms and SS+ TB was respectively 40 and 132. The NNT to diagnose a TB case all forms and SS+ TB was respectively 2.4 and 8. Of 1687 eligible children aged <5 years, 323 were started on isoniazid preventive therapy. CONCLUSIONS: The yield of the household contact investigation was over 10 times higher than the estimated prevalence in the general population; household contact investigations can serve as an entry point for childhood TB care.

A simple micro-assay method for estimating blood meal size of the sand fly, Phlebotomus langeroni (Diptera: Psychodidae).

The accurate measurement of blood meal size in Phlebotomus langeroni, the potential vector of infantile visceral leishmaniasis in Egypt, is important to determine the number of parasites taken in fully engorged insects. A simple protein content micro-assay is introduced for that purpose. The accuracy of this method was confirmed by hemoglobin estimation method. Laboratory bred P. langeroni were fed artificially on defibrinated human blood and the fully engorged flies were carefully dissected on ice, within 1-10 min after feeding, since the time of dissection is critical. Serial concentrations of the defibrinated human blood were required as standards. Results show that the full blood meal taken by P. langeroni ranged from 0.76-0.94 mm3 of blood with a mean volume of 0.85 +/- 0.02 mm3 and from 0.71- 0.99 mm3 of blood with a mean volume of 0.83 +/- 0.02 mm3 as measured by protein content and hemoglobin estimation methods respectively. The data showed that there is no significant difference (P=0.27) between the two methods in estimating the blood meal size of P. langeroni. In addition, protein content micro-assay had the advantages of being accurate, rapid, sensitive and reliable.

Vector-host-parasite inter-relationships in leishmaniasis. I. The effect of Leishmania parasites on rate of digestion of blood proteins from various vertebrate hosts by the sand fly Phlebotomus langeroni (Diptera: Psychodidae).

Protein digestion in the gut of Phlebotomus langeroni (Nitzulescu) was studied at four subsequent 24 hour intervals post feeding on human, dog (Canis familiaris), rat (Rattus rattus) and turkey (Melagris gallopava) bloods with and without Leishmania infantum or L. major promastigotes. Most of the proteins of the studied blood meals were digested within 96 hours. The percent of blood proteins digested in the first 48 hours was higher than in the second 48 hours in all cases of the studied blood meals except the normal blood of the turkey in which the ratio of the digested blood proteins in the two periods was 1:1. During the first 48 hours, the percent of the digested blood proteins was lower than normal in the presence of L. infantum in case of human and dog blood meals. The reverse was true in case of the rat and turkey blood meals in the presence of L. infantum and in the blood meals from each of the four vertebrate hosts in the presence of L. major. The significance of these findings in considering L. infantum as a natural parasite of P. langeroni in El Agamy focus was discussed.

Vector-host-parasite inter-relationships in leishmaniasis. II. Influence of blood meal from natural vertebrate hosts with and without Leishmania infantum and L. major on the proteolytic activity in the gut of Phlebotomus langeroni (Diptera: Psychodidae).

Proteolytic activity in the gut of Phlebotomus langeroni (Nitzulescu) was studied at four subsequent 24 hours intervals post feeding on human, dog (Canis familiaris), rat (Rattus rattus) and turkey (Melagris gallopava) bloods with and without Leishmania infantum or L. major promastigotes. The gut proteolytic activity increased gradually after feeding to reach a maximum at 48 hours post feeding on any of the 12 studied blood meals. In all cases, the activity declined after 48 hours and almost terminated by 96 hours. In case of normal bloods, the proteolytic activity, at 48 hours post feeding, was the highest in case of dog followed by human, rat and turkey respectively. At this time interval the activity was relatively lower in case of human and dog blood mixed with L. infantum promastigotes than in their respective normal blood. The reverse was true in all other blood meal combinations. Promastigotes were alive and active in fresh gut smears of P. langeroni fed on human, dog and rat bloods mixed with either L. infantum or L. major, throughout the digestion period (1-4 days). They were arrested in P. langeroni within the first day post feeding on turkey blood mixed with either Leishmania species. The results of the present study indicate that the kind of blood meal and the Leishmania species affect the proteolytic activity of P. langeroni. The decrease or increase of the proteolytic activity of P. langeroni has no effect on the survival of Leishmania parasites present in the gut and the kind of blood meal is responsible for their development.

Vector-host-parasite inter-relationships in leishmaniasis. III. Impact of blood meal from natural vertebrate hosts on the survival and the development of Leishmania infantum and L. major in Phlebotomus langeroni (Diptera: Psychodidae).

Phlebotomus langeroni collected from a leishmaniasis endemic focus at Et Agamy, Alexandria, Egypt, were found to have fed on blood from man, dogs (Canis familiaris) and rats (Rattus rattus). The effect of the kind of blood meal on the development and the life-cycle of L. infantum and L. major in laboratory reared P. langeroni was therefore investigated. A membrane feeding technique was used to infect sand flies. Gut smears of infected females were examined immediately after feeding and daily for 16 days. Nectomonads and short promastigote forms of L. infantum or L. major were detected in females fed on human, dog and rat bloods at all intervals. Paramastigotes (infective stage) were present only in females fed on dog blood containing L. infantum or L. major and in those fed on rat blood containing L. major. It is concluded that among the factors influencing the Leishmania-phlebotomus relationship is the natural medium in which the parasite is present in vivo. The blood of the natural reservoir host(s) is the key factor for the development of the infective parasite form in the sand fly and P. langeroni could be considered a potential vector for transmitting L. infantum from dogs and L. major from rats and dogs but not from man. This investigation offers a new concept for the study of interactions among vector, host and parasites in Leishmania transmission.

Vector-host-parasite inter-relationships in leishmaniasis. IV. Electrophoretic studies on proteins of four vertebrate bloods with and without Leishmania infantum or L. major.

Fifty five protein bands with relative mobilities of 8,954 to 245,471 kilo Daltons (kD) were electrophoretically separated from 12 feeding media of blood from 4 natural vertebrate hosts of Phlebotomus langeroni. The feeding media included human, dog (Canis familiaris), rat (Rattus rattus) and turkey (Melagris gallopava) bloods without or with Leishmania infantum or L. major promastigotes. Protein bands were identical among the feeding media of one host's blood but varied in number (24-28 bands) and relative mobilities among the various hosts' blood. Some protein fractions were common among the various hosts blood, others were only present in two or three hosts' blood and some were restricted to one host blood and were unique for each host. This study provides data which may help in understanding why blood from different natural hosts may variably influence the life cycle of Leishmania parasite in the sand fly gut.

Feeding patterns of Phlebotomus papatasi and Phlebotomus langeroni (Diptera: Psychodidae) in El Agamy, Egypt.

Blood meals from 602 Phlebotomus papatasi (Scopoli) and 49 Phlebotomus langeroni Nitzulescu were collected in El Agamy, Egypt, and were identified using counterimmunoelectrophoresis. Blood meals were tested against specific antisera of eight vertebrate hosts (human, cat, dog, rat, sheep, goat, general avian, and general bovine). Of 597 P. papatasi collected indoors, 594 contained human blood and three had mixed blood meals (human-dog, human-rat, and human-avian). Four of five P. papatasi collected outdoors contained human blood and one contained avian blood. All 39 P. langeroni collected indoors had fed on humans. Six of 10 outdoor-collected P. langeroni had fed on human blood, 2 on dog, 1 on cat, and 1 on rat blood. Both P. papatasi and P. langeroni feed predominantly on humans in El Agamy, Egypt. The documented feeding on humans and dogs by P. langeroni supports the role of this species as the primary vector of visceral leishmaniasis at the El Agamy focus.