Overcoming the inhibitory effects of urea to improve the kinetics of microbial-induced calcium carbonate precipitation (MICCP) by Lysinibacillus sphaericus strain MB284.

Among different microbial-induced calcium carbonate precipitation (MICCP) mechanisms utilized for biomineralization, ureolysis leads to the greatest yields of calcium carbonate. Unfortunately, it is reported that urea-induced growth inhibition can delay urea hydrolysis but it is not clear how this affects MICCP kinetics. This study investigated the impact of urea addition on the MICCP performance of Lysinibacillus sphaericus MB284 not previously grown on urea (thereafter named bio-agents), compared with those previously cultured in urea-rich media (20 g/L) (hereafter named bio-agents+ or bio-agents-plus). While it was discovered that initial urea concentrations exceeding 3 g/L temporarily hindered cell growth and MICCP reactions for bio-agents, employing bio-agents+ accelerated the initiation of bacterial growth by 33% and led to a 1.46-fold increase in the initial yield of calcium carbonate in media containing 20 g/L of urea. The improved tolerance of bio-agents+ to urea is attributed to the presence of pre-produced endogenous urease, which serves to reduce the initial urea concentration, alleviate growth inhibition, and expedite biomineralization. Notably, elevating the initial concentration of bio-agents+ from OD600 of 0.01 to 1, housing a higher content of endogenous urease, accelerated the initiation of MICCP reactions and boosted the ultimate yield of biomineralization by 2.6 times while the media was supplemented with 20 g/L of urea. These results elucidate the advantages of employing bio-agents+ with higher initial cell concentrations to successfully mitigate the temporary inhibitory effects of urea on biomineralization kinetics, offering a promising strategy for accelerating the production of calcium carbonate for applications like bio self-healing of concrete.

Provincial clustering of malaria in Iran between 2005 and 2014

Objective: To reveal the provincial clustering of malaria in Iran between 2005 and 2014 based on the epidemiologic factors and the climatic indicators affecting the disease. Methods: This was a descriptive-analytical study using malaria and meteorological data from the Malaria Elimination Programme of the Ministry of Health and Medical Education and National Meteorological Organization. After standardization, the aggregate data was used to produce 10-year means for each province. The data analysis included grouping the provinces with respect to factors using hierarchical clustering method and Kruskal-Wallis test to examine the difference between clusters using SPSS ver.23. Results: The hierarchical clustering stratified the provinces' in 5 clusters. Kruskal-Wallis H test revealed a significant difference in the incidence rate per 100 000 population (P=0.001), male gender (P=0.001), Iranian nationality (P=0.001), Afghan nationality (P=0.003), Pakistani nationality (P=0.001), urban residence (P=0.006), rural residence (P=0.004), autochthonous cases (P=0.007), average minimum temperature (P=0.001), average maximum temperature (P=0.007), average relative humidity (P=0.011), average pressure level (P=0.038), prevailing wind direction (P=0.023), average wind speed (P=0.031) and average precipitation sum (P=0.002) among the clusters. Conclusions: The results of this study and stratification of the provinces could help health policy makers to better manage malaria by allocating resources accordingly.

Wash resistance and bio-efficacy of Olyset Plus, a long-lasting insecticide-treated mosquito net with synergist against malaria vector, Anopheles stephensi

OBJECTIVE@#To determine the wash resistance of Olyset Plus using World Health Organization Pesticide Evaluation Scheme standard washing procedure and to assess the value of knock down and mortality rates of Anopheles stephensi at different regimens of long lasting insecticide treated nets washings.@*METHODS@#The study was conducted at the Bioassay Laboratory of Culicidae Insectary, School of Public Health, Tehran University of Medical Sciences, Iran. The net was made of polyester impregnated with permethrin and piperonyl butoxide at a ratio of 2:1. The washing resistance was assessed using Le Chat soap and a shaker incubator set at a speed of 155 r/min, 30 °C for 10 min. The cone bioassay test was carried out according to World Health Organization recommended guideline with tolerant field strain of female Anopheles stephensi to pyrethroids.@*RESULTS@#The knockdown and mortality rates of female mosquitoes exposed to Olyset Plus from un-washed nets to 2 washings were 79.7% and 88.8% respectively. Mortality was dropped to zero while active ingredient estimated 0.532 μg/100 cm to 0.481 μg/100 cm after 15 washings. A positive correlation was seen between residues of permethrin on nets, knockdown rate and mortality rate of female Anopheles stephensi exposed to different regimes of washed Olyset Plus (r = 0.954, P = 0.001).@*CONCLUSIONS@#It is recommended that a preliminary survey conducted on resistance level of Anopheles vectors before the distribution of Olyset Plus in malaria endemic communities.

Wash resistance and bio-efficacy of Olyset

Objective To determine the wash resistance of Olyset

Epidemiological status of malaria in Iran, 2011-2014

OBJECTIVES@#To aim to determine the status and epidemiological aspects of malaria in Iran in favour of gaining a better understanding of the national control of malaria.@*METHODS@#This epidemiological study examined the status of malaria from 2011 to 2014 in Iran. Data were collected from the Ministry of Health's protocol for controlling and eliminating malaria, which is currently in use. This malaria information reporting system is automated in all Iranian provinces and cities, and all information is submitted online to the center for communicable disease control in the Ministry of Health. Information about malaria is available for researchers to evaluate.@*RESULTS@#The incidence rates decreased from 2011 to 2014. There were 4.76, 2.12, 1.80, and 1.59 per 100000 people, respectively from 2011 to 2014. During the four-year period (2011-2014), the highest numbers of cases occurred in those aged 16-25 years, by age, and in men, by sex. Most of the cases were workers and located in rural areas. An average 52.58% of cases were Iranian. The highest incidence rates from 2011 to 2014 were located in Sistan and Baluchestan province. There were 89.94, 43.9, 38.3, and 30.66 per 100000 people. The highest numbers of malaria cases were recorded in the cities Sarbaz, Nickshahr, and Chabahar in Sistan and Baluchestan province and Bandar Abbas, Bandar Jask, and Bandar Lengeh in Hormozgan province. During the four-year period, 57.05% of cases were caused by imported factors. The majority of cases were related to the trophozoite lifecycle of parasites. Regarding surveillance, there was inactive care in the majority of cases. Vivax malaria was the most prevalent.@*CONCLUSIONS@#Despite the recently declining trend in reported cases, the expansion of local transmission, especially in areas with cross-border travel, is very worrying. Improved malaria control interventions can be effective for elimination of malaria in Iran; these can include programs to control border travel and focused interventions for high incidence areas and high-risk groups such as rural residents, men, workers, and people <35 years old.

Bio-ecology of malaria vectors in an endemic area, Southeast of Iran

Objective: To determine some bio-ecological aspects of malaria vectors in Jask County, where is targeted for malaria elimination in the national program. Methods: Mosquitoes were collected monthly during 2013-2014 using different collection methods. Subsequently, ELISA test was used to detect the human blood index of mosquitoes. The susceptibility status of Anopheles stephensi was evaluated against the diagnostic dosages of seven WHO recommended insecticides. Results: A total of 3. 650 female and 4. 736 Anopheles larvae were collected including Anopheles stephensi, Anopheles culicifacies s.l., Anopheles dthali, Anopheles fluviatilis s.l., Anopheles moghulensis and Anopheles turkhodi species. Anopheles stephensi was the dominant collected species on human baits and indoors with high rate of unfed and gravid specimens in internal and external window traps. Human blood index was calculated as 14.3% for this species. It was also found to be resistant to DDT and Dieldrin. Conclusions: The collected species had a wide range of habitats, and resting behaviors. With regarding to the presence of most important malaria vectors in Jask, control of the disease may be so complicated; as based on the weather condition it can be transmitted during the whole year, expect for cold months. With this strong potential of transmission, existing population movements in the area may lead to imported cases of malaria and local outbreak(s). So, more specific studies on malaria vectors in high risk areas of Jask County are recommended.

Epidemiological status of malaria in Iran, 2011–2014

Objectives To aim to determine the status and epidemiological aspects of malaria in Iran in favour of gaining a better understanding of the national control of malaria. Methods This epidemiological study examined the status of malaria from 2011 to 2014 in Iran. Data were collected from the Ministry of Health's protocol for controlling and eliminating malaria, which is currently in use. This malaria information reporting system is automated in all Iranian provinces and cities, and all information is submitted online to the center for communicable disease control in the Ministry of Health. Information about malaria is available for researchers to evaluate. Results The incidence rates decreased from 2011 to 2014. There were 4.76, 2.12, 1.80, and 1.59 per 100 000 people, respectively from 2011 to 2014. During the four-year period (2011–2014), the highest numbers of cases occurred in those aged 16–25 years, by age, and in men, by sex. Most of the cases were workers and located in rural areas. An average 52.58% of cases were Iranian. The highest incidence rates from 2011 to 2014 were located in Sistan and Baluchestan province. There were 89.94, 43.9, 38.3, and 30.66 per 100 000 people. The highest numbers of malaria cases were recorded in the cities Sarbaz, Nickshahr, and Chabahar in Sistan and Baluchestan province and Bandar Abbas, Bandar Jask, and Bandar Lengeh in Hormozgan province. During the four-year period, 57.05% of cases were caused by imported factors. The majority of cases were related to the trophozoite lifecycle of parasites. Regarding surveillance, there was inactive care in the majority of cases. Vivax malaria was the most prevalent. Conclusions Despite the recently declining trend in reported cases, the expansion of local transmission, especially in areas with cross-border travel, is very worrying. Improved malaria control interventions can be effective for elimination of malaria in Iran; these can include programs to control border travel and focused interventions for high incidence areas and high-risk groups such as rural residents, men, workers, and people <35 years old.

Bio-ecology of malaria vectors in an endemic area, Southeast of Iran

OBJECTIVE@#To determine some bio-ecological aspects of malaria vectors in Jask County, where is targeted for malaria elimination in the national program.@*METHODS@#Mosquitoes were collected monthly during 2013-2014 using different collection methods. Subsequently, ELISA test was used to detect the human blood index of mosquitoes. The susceptibility status of Anopheles stephensi was evaluated against the diagnostic dosages of seven WHO recommended insecticides.@*RESULTS@#A total of 3650 female and 4736 Anopheles larvae were collected including Anopheles stephensi, Anopheles culicifacies s.l., Anopheles dthali, Anopheles fluviatilis s.l., Anopheles moghulensis and Anopheles turkhodi species. Anopheles stephensi was the dominant collected species on human baits and indoors with high rate of unfed and gravid specimens in internal and external window traps. Human blood index was calculated as 14.3% for this species. It was also found to be resistant to DDT and Dieldrin.@*CONCLUSIONS@#The collected species had a wide range of habitats, and resting behaviors. With regarding to the presence of most important malaria vectors in Jask, control of the disease may be so complicated; as based on the weather condition it can be transmitted during the whole year, expect for cold months. With this strong potential of transmission, existing population movements in the area may lead to imported cases of malaria and local outbreak(s). So, more specific studies on malaria vectors in high risk areas of Jask County are recommended.

Molecular characterization, biological forms and sporozoite rate of Anopheles stephensi in southern Iran

<p><b>OBJECTIVE</b>To identify the biological forms, sporozoite rate and molecular characterization of the Anopheles stephensi (An. stephensi) in Hormozgan and Sistan-Baluchistan provinces, the most important malarious areas in Iran.</p><p><b>METHODS</b>Wild live An. stephensi samples were collected from different malarious areas in southern Iran. The biological forms were identified based on number of egg-ridges. Molecular characterization of biological forms was verified by analysis of the mitochondrial cytochrome oxidase subunit I and II (mtDNA-COI/COII). The Plasmodium infection was examined in the wild female specimens by species-specific nested-PCR method.</p><p><b>RESULTS</b>Results showed that all three biological forms including mysorensis, intermediate and type are present in the study areas. Molecular investigations revealed no genetic variation between mtDNA COI/COII sequences of the biological forms and no Plasmodium parasites was detected in the collected mosquito samples.</p><p><b>CONCLUSIONS</b>Presence of three biological forms with identical sequences showed that the known biological forms belong to a single taxon and the various vectorial capacities reported for these forms are more likely corresponded to other epidemiological factors than to the morphotype of the populations. Lack of malaria parasite infection in An. stephensi, the most important vector of malaria, may be partly due to the success and achievement of ongoing active malaria control program in the region.</p>

Bioassay evaluation on the efficacy of α-cypermethrin impregnated into long lasting insecticide treated nets using Anopheles stephensi.

OBJECTIVE: To evaluate the bioefficacy of α-cypermethrin impregnated into long lasting insecticide treated nets (LLITNs-INTERCEPTOR®) against main malaria vector, Anopheles stephensi (An. stephensi). METHODS: The effectiveness of bed net impregnated with α-cypermethrin (INTERCEPTOR®) with washing was evaluated. The washing procedure and bioassay tests were carried out according to the WHO-recommended methods. Malaria vector, An. stephensi was exposed to impregnated bed net for three minutes and then mortality measured after 24 h recovery period. Knockdown was also measured according to the logarithmic times. RESULTS: Result of cone bioassay method showed that bioefficacy of α-cypermethrin decreased from 100% in unwashed to 15% in 20 washes. KT(50) was measure as one minute in one wash and increased to 40 min in 20 washes. DISCUSSION: Findings of this study provide guideline for malaria vector control authorities and people using pyrethroid-impregnated bed nets.

Spatial outline of malaria transmission in Iran

OBJECTIVE@#To conduct for modeling spatial distribution of malaria transmission in Iran.@*METHODS@#Records of all malaria cases from the period 2008-2010 in Iran were retrieved for malaria control department, MOH&ME. Metrological data including annual rainfall, maximum and minimum temperature, relative humidity, altitude, demographic, districts border shapefiles, and NDVI images received from Iranian Climatologic Research Center. Data arranged in ArcGIS.@*RESULTS@#99.65% of malaria transmission cases were focused in southeast part of Iran. These transmissions had statistically correlation with altitude (650 m), maximum (30 °C), minimum (20 °C) and average temperature (25.3 °C). Statistical correlation and overall relationship between NDVI (118.81), relative humidity (⩾45%) and rainfall in southeast area was defined and explained in this study.@*CONCLUSIONS@#According to ecological condition and mentioned cut-off points, predictive map was generated using cokriging method.

Demonstration of malaria situation analysis, stratification and planning in Minab District, southern Iran.

OBJECTIVE: To demonstrate malaria situation analysis, stratification and planning for an endemic area in southern Iran. METHODS: Data on health system, population, meteorological parameters, malaria cases, anopheline vectors, and control activities during 2005-2007 was obtained from Minab Health Center, Minab Meteorological Station and published documents about malaria elements in the study area. A datasheet was created in excel 2003 for analysis. RESULTS: There were 644 health staff working in Minab District including 99 health staff in malaria control program. The health facilities are distributed as follow: 1 hospital with 96 beds, 23 health centers including private centers (10 in Minab city and 13 in rural area of Minab District) and 119 health houses in rural areas of Minab District. A nopheles stephensi was the dominant species in Minab District, however, Anopheles dthali, Anopheles superpictus, Anopheles fluviatilis, Anopheles multicolor, Anopheles pulcherrimus and Anopheles turkhudi can also be found in the area. Anopheles stephensi was reported susceptible to malathion, propoxur, primphos-methyl, lambda-cyhalothrin permethrin and deltamethrin, and resistant to DDT and dieldrin in the area. During the study period a total of 10 665 positive cases were reported, mainly due to local transmission (99.6%). Plasmodium vivax was the main causative agent followed by Plasmodium falciparum. There were reports about drug resistance of Plasmodium falciparum in the area. CONCLUSIONS: Using different parameters, Minab was classified into 3 strata. A plan was designed based on described goal, objectives and targets. The approaches of this plan were categorized into: health education, early detection and correct treatment, and vector control. Main constraints of these approaches are population movement between Iran, Pakistan and Afghanistan; vector control challenges at district, inadequate skilled medical staff in malaria case management and weak inter-sectorial coordination for malaria control, especially in urban areas.

A cross-linking model for estimating Young's modulus of artificial bone tissue grown on carbon nanotube scaffold.

Carbon nanotubes (CNTs) provide a suitable environment for growth and proliferation of bone cells. The elastic properties exhibited by CNTs can enhance mechanical characteristics of bone mineral phase, hydroxyapatite (HAp), precipitated on such a scaffold. In this article, a simplified model for estimating the axial Young's modulus of a representative volume element (RVE) of CNT-HAp composite is presented. The model is based on the idea of HAp formation on functionalized sites on CNTs as cross-links between HAp matrix and CNT. Modeling results show that the reinforcement role contributed by CNT in the RVE causes a significant increase in the Young's modulus of the composite material which is a direct consequence of transferring stresses from the HAp matrix to the CNT through the cross-links. Similar conclusions may be suggested regarding the improvement of overall mechanical properties of the material. The prediction made by the model lies reasonably well within the limits proposed by conventional Rule-of-Mixtures, and sliding below Voigt's model. The Young's modulus predicted by the model lies adjacent to the Hashin-Shtrikman upper bound as a function of the RVE length (or equivalently CNT aspect ratio). The model simulation indicates that an increase in the CNT aspect ratio and/or number of cross-links in the RVE, results in the prediction to move closer to the estimation made by Voigt as the assumption of perfect bonding between composite phases is approached.