Lifestyle and occupation risk factors for poor semen quality: a cross sectional study in Sri Lanka

Background: Infertility is a major problem all around the world. According to WHO, the rate of infertility is approximately 15% worldwide and it differ from geographical location, ethnicity and social status. Lifestyle habits, environmental and occupational hazards, physical parameters can be recognized as major risk factors which may affect male infertility. The objective of this study was to determine factors associated with male infertility in Sri Lankan context.Methods: A cross-sectional study was conducted on 299 individuals participated for an infertility clinic at Castle Street Teaching Hospital, Colombo, Sri Lanka. Socio-demographic, occupational and environmental characteristics were collected using interviewer administered questionnaire. Semen samples were collected from each participant for laboratory investigations. Sperm concentration and motility were measured.Results: Out of total participants, 30.1% of participants had a sperm concentration of <15×10⁶ and the sperm motility was <32% in 34.7% participants.  Older age, tobacco smokers, using tight under wears and individuals exposed to either heat or chemical hazards were identified as risk groups with low sperm concentration and low semen volume. In addition, older age, individuals using tight under wears and individuals exposed to either heat or chemical hazards were significantly associated with low or abnormal sperm mortality. Individuals having diabetes showed a significantly higher non-motility rate of sperms. Alcohol usage, betel chewing, mumps, special radiation exposure, body mass index and waist circumference were not significantly associated with semen parameters in study population.Conclusions: Older age, tobacco smoking, wearing tight underwear, occupational exposures, and diabetes mellitus has shown a risk for the generation of poor semen parameters, which can lead to male infertility. Furthermore, it is very important to carry out extended studies regarding this problem to establish the effect of above factors

Larvicidal Potential of Five Selected Dragonfly Nymphs in Sri Lanka over Aedes aegypti (Linnaeus) Larvae under Laboratory Settings

Introduction. Limitations in breeding source reduction practices, development of insecticide resistance in mosquitoes, and ill effects of chemical controlling methods on human and ecosystem health have motivated Sri Lankan authorities working for dengue control to seek for alternative, ecofriendly, and sustainable approaches for controlling of Aedes vectors, to manage dengue epidemics. The present study attempted to investigate the predation efficiency of locally available dragonfly nymphs over Aedes aegypti under laboratory conditions, aiming to evaluate the potential of using dragonflies as biocontrol agents against dengue. Methods. Nymphal stages of five locally abundant dragonfly species were collected from different stagnated water bodies in Belihuloya area. After morphological identification, a well grown individual of each species was starved for 12 hours and introduced into a glass tank containing 1L of pond water with 200 larvae (4th instar) of Aedes aegypti. Number of larvae survived in the tank was enumerated hourly up to 48 hours. In case where >75% of larvae are consumed by dragonfly nymphs, additional Ae. aegypti larvae were introduced into such tanks. Experiment was repeated for five times. Same procedure was followed with different stages of growth of the dragonfly nymphs characterized by the highest predation rate. General Linear Model followed by Tukey’s pairwise comparison was used for statistical analysis. Results. The predation rates of different dragonfly species varied significantly (p<0.05), whereby Anax indicus (110±7.14 per day) indicated the highest, followed by Pantala flavescens (54.07±5.15) and Gynacantha dravida (49.00±11.89), while Tholymis tillarga (23.47±2.48) had the lowest. Further, significant variations in the larval predation were found among different maturity stages (10–20; 25-35; and 35–45 mm in body length) of Ana. indicus (p<0.05). Regardless of statistical significance, a relatively higher larvicidal activity was observed at dusk than in dawn. Conclusion. Ana. indicus, which is characterized by the highest predation rate, and P. flavescens that has the widest geographical distribution within Sri Lanka along with a notable predation efficacy could be recommended as potential candidates for field trials in biological control of dengue outbreaks via suppression of Ae. aegypti larvae

Modification of Thermal Conductivity of Cotton Fabric Using Graphene

This paper investigates the possibility to use Graphene coated fabric for thermal conductive purposes. Existing methods of thermal conductivity improvement of textiles require extrusion facilities and the end products are heavy due to insertion of metal wires. By using Graphene Oxide application, these disadvantages can be eliminated. Graphene Oxide was applied onto the fabric using a simple dip and dry method and an exhaustion dyeing method. Then the coated fabric was allowed to react with an aqueous solution of reducing agents. The test results showed that the most suitable method to obtain a significant improvement in thermal conductivity of textiles is to follow an exhaustion dyeing method with reducing agents. The reduction process should be maintained at 700C for 30min duration with the addition of Sodium Hydrosulphide. Exhaust dyed fabric which was treated with reducing agents showed an improvement of 55% in thermal conductivity compared to the uncoated fabric, which is a significant improvement in the thermal conductivity of textiles. In addition to the thermal conductivity values, few related textile properties were tested to evaluate the effect of the Graphene coating on the fabric characteristics.IEEE IEEE Sri Lanka Section Robotics and Automation Section Chapter, IEEE Sri Lanka Sectio

Corrigendum to “Larvicidal Potential of Five Selected Dragonfly Nymphs in Sri Lanka over Aedes aegypti (Linnaeus) Larvae under Laboratory Settings”

Introduction. Limitations in breeding source reduction practices, development of insecticide resistance in mosquitoes, and ill effects of chemical controlling methods on human and ecosystem health have motivated Sri Lankan authorities working for dengue control to seek for alternative, ecofriendly, and sustainable approaches for controlling of Aedes vectors, to manage dengue epidemics. The present study attempted to investigate the predation efficiency of locally available dragonfly nymphs over Aedes aegypti under laboratory conditions, aiming to evaluate the potential of using dragonflies as biocontrol agents against dengue. Methods. Nymphal stages of five locally abundant dragonfly species were collected from different stagnated water bodies in Belihuloya area. After morphological identification, a well grown individual of each species was starved for 12 hours and introduced into a glass tank containing 1L of pond water with 200 larvae (4th instar) of Aedes aegypti. Number of larvae survived in the tank was enumerated hourly up to 48 hours. In case where >75% of larvae are consumed by dragonfly nymphs, additional Ae. aegypti larvae were introduced into such tanks. Experiment was repeated for five times. Same procedure was followed with different stages of growth of the dragonfly nymphs characterized by the highest predation rate. General Linear Model followed by Tukey’s pairwise comparison was used for statistical analysis. Results. The predation rates of different dragonfly species varied significantly (p<0.05), whereby Anax indicus (110±7.14 per day) indicated the highest, followed by Pantala flavescens (54.07±5.15) and Gynacantha dravida (49.00±11.89), while Tholymis tillarga (23.47±2.48) had the lowest. Further, significant variations in the larval predation were found among different maturity stages (10–20; 25-35; and 35–45 mm in body length) of Ana. indicus (p<0.05). Regardless of statistical significance, a relatively higher larvicidal activity was observed at dusk than in dawn. Conclusion. Ana. indicus, which is characterized by the highest predation rate, and P. flavescens that has the widest geographical distribution within Sri Lanka along with a notable predation efficacy could be recommended as potential candidates for field trials in biological control of dengue outbreaks via suppression of Ae. aegypti larvae

Comparison of the kinetics and magnitude of antibody responses to different SARS-CoV-2 proteins in Sinopharm/BBIBP-CorV vaccinees following the BNT162b2 booster or natural infection.

The kinetics and magnitude of antibody responses to different proteins of the SARS-CoV-2 virus in Sinopharm/BBIBP-CorV vaccinees has not been previously studied. Therefore, we investigated antibody responses to different SARS-CoV-2 proteins at 2 weeks, 3 months, and 6 months post-second dose in previously infected (n = 20) and uninfected (n = 20) Sinopharm/BBIBP-CorV vaccinees. The IgG antibodies to the S, S1 and S2 and N were several folds higher in those who had natural infection compared to uninfected individuals at all time points. We then compared the persistence of antibody responses and effect of natural omicron infection or BNT162b2 booster in Sinopharm/BBIBP-CorV vaccinees. We measured the total antibodies to the RBD, ACE2 blocking antibodies and antibody responses to different SARS-CoV-2 proteins in Sinopharm vaccinees at 7 months post second dose, including those who remained uninfected and not boosted (n = 21), or those who had previous infection and who did not obtain the booster (n = 17), those who were not infected, but who received a BNT162b2 booster (n = 30), or those who did not receive the booster but were infected with omicron (n = 29). At 7 months post second dose uninfected (no booster) had the lowest antibody levels to the RBD, while omicron infected vaccinees showed significantly higher anti-RBD antibody levels (p = 0.04) than vaccinees who received the booster. Only 3/21 cohort A (14.3%) had ACE2 blocking antibodies, while higher frequencies were observed in naturally infected individuals (100%), those who received the booster (18/21, 85.7%), and omicron infected individuals (100%). Pre-vaccination, naturally infected had the highest antibody levels to the N protein. These data suggest that those previously infected Sinopharm/BBIBP-CorV vaccinees have a robust antibody response, 7 months post vaccination, while vaccinees who were naturally infected with omicron had a similar immune response to those who received the booster. It will be important to investigate implications for subsequent clinical protection