Thermoplasmonic ssDNA Dynamic Release from Gold Nanoparticles Examined with Advanced Fluorescence Microscopy

Plasmon excitation of spherical gold nanoparticles carrying a fluorescent labeled 30 bp dsDNA cargo, with one chain covalently attached through two S–Au bonds to the surface, results in release of the complementary strand as ssDNA that can be examined in situ using high-resolution fluorescence microscopy. The release is dependent on the total energy delivered, but not the rate of delivery, an important property for plasmonic applications in medicine, sensors, and plasmon-induced PCR

Dense monocular reconstruction using surface normals

This paper presents an efficient framework for dense 3D scene reconstruction using input from a moving monocular camera. Visual SLAM (Simultaneous Localisation and Mapping) approaches based solely on geometric methods have proven to be quite capable of accurately tracking the pose of a moving camera and simultaneously building a map of the environment in real-time. However, most of them suffer from the 3D map being too sparse for practical use. The missing points in the generated map correspond mainly to areas lacking texture in the input images, and dense mapping systems often rely on hand-crafted priors like piecewise-planarity or piecewise-smooth depth. These priors do not always provide the required level of scene understanding to accurately fill the map. On the other hand, Convolutional Neural Networks (CNNs) have had great success in extracting high-level information from images and regressing pixel-wise surface normals, semantics, and even depth. In this work we leverage this high-level scene context learned by a deep CNN in the form of a surface normal prior. We show, in particular, that using the surface normal prior leads to better reconstructions than the weaker smoothness prior.Chamara Saroj Weerasekera, Yasir Latif, Ravi Garg, Ian Rei

Evaluation of Earthworm Species and Bedding Material Collected from Tea Plantations for Vermicomposting in Sri Lanka

Earthworms has the ability to convert organic waste into compost and this process is known as vermicomposting. This study was conducted to evaluate the suitability of three common earthworm species and four waste material collected from tea plantations as bedding material for earthworms in producing vermicompost. Three experiments were conducted and the experimental design was a Complete Randomized Design with three replicates. In the first experiment, four bedding materials that is leaves of Gliricidia (Gliricidia sepium) and Mana (Cymbopogon confertiflorus), tea prunings and refuse tea were composted using earthworm species Eudrilus euginea. Each waste material was mixed with cow dung and poultry manure, separately before using them as bedding material. The results showed that these material can be used for producing high quality vermicompost. In the second experiment three earthworm species Eisenia foetida, Periyonix excavator and Eudrilus euginea which were commonly recorded from Sri Lankan soils were evaluated for vermicomposting. Vermicomposting has increased the quality of organic material but the mean differences in nutrient levels in relation to earthworm species were non-significant (P=0.05). This indicates the suitability of all three species for vermicomposting. In the third experiment three soil amendments, vermicompost produced using Eudrilus euginea, garden compost and inorganic fertilizer were compared using tomato as an indicator crop. Vermicompost applied treatment showed significantly higher (

Clinico-demographic characterization of Cutaneous leishmaniasis in patients reporting to two hospitals in Matara and Hambantota districts, Sri Lanka

Background: Cutaneous leishmaniasis (CL) is an established disease in Sri Lanka.Objectives: This study aimed to characterize clinico-demographic pattern of CL, in patients reported to District General Hospital (DGH) Matara and Base Hospital (BH) Tangalle, which report about 100 new cases monthly.Methods: Clinico-demographic findings of 47 CL confirmed patients (>18 years; Slit skin smears (SSS) and/or PCR positive) from preliminary data of a cross sectional study carried out at DGH Matara and BH Tangalle from August/2018 to January /2019 were analysed. Interviewer administered questionnaire was used to gather the demographic data.Results: Median age was 43 years. Out of the 13 cases from DGH Matara, four reported from Urugamuwa and one each from other areas of the district. Of the 34 cases from BHTangalle, 12 were from Beliaththa. Eight SSS negatives became PCR positive and one PCR negative was SSS positive. Majority of the lesions were single (n=40, 85.1%), non-tender (n=38, 80.8%), non-itchy (n=34, 72.3%) and small (< 2cm, n=36, 76.6%) ulcerated nodules (n=14, 29.8%) in upper limbs (n=25, 53.1%) with parasitic grading of 1+ (n=20, 42.5%). Nine patients reported persistent itching without any evidence of secondary pathology. Clinical evidence of secondary bacterial infection presented in four patients and out of them, two had painful lesions. Thirty two lesions were <4 months duration. In addition to ulcerated nodules and plaques, three out of nine papules were ulcerated within 4 months’ by history. Two patients had a family member with CL.Conclusions: Ulceration of papules is a novel observation. Urugamuwa is a possible emerging focus of CL in Matara where Dickwella is the known hot spot. Beliathta could be a main disease focus in Hambantota. This preliminary study based on a smaller sample size needs to be validated with a bigger sample size

Bacteria mediated silver nanoparticles: comparison as potent antibiofilm agents

Introduction: Biosynthesized silver nanoparticles (AgNPs) have good antimicrobial properties comparable to chemically synthesized silver nanoparticles. Further, they have good potential as antibiofilm agents.Methods: AgNPs were synthesized from Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923) and Acinetobacter baumannii (confirmed clinical isolate) and physically characterized by several techniques. The antibiofilm activity of the AgNPs against biofilms of P. aeruginosa, S. aureus and C. albicans was studied using crystal violet assay. Biofilms were formed in 96-well polystyrene plates and treated with biosynthesized AgNPs for 24 and 48 h.Results: AgNPs synthesized by all bacteria except S. aureus mediated AgNPs displayed 50% biofilm inhibition at AgNP concentrations between 1.98 - 0.225 mg/ml. S. aureus mediated AgNPs showed 50% biofilm inhibition only against S. aureus biofilm. Scanning Electron microscopic images indicated that biosynthesized AgNPs were able to decrease surface coverage of biofilms and to reduce the extracellular matrix causing morphological changes in biofilms noticeably.Conclusion: This study reports the antibiofilm activity of bacteria mediated AgNPs. This is the first report on antibiofilm activity of AgNPs synthesized by Acinetobacter baumannii and also as a comparison of antibiofilm activity of several bacteria mediated AgNPs. According to the results, low dosages of green AgNPs can be applied in treating drug-resistant microbial infections in a cost effective manner. In conclusion, the bacterial synthesized AgNPs have antibiofilm activity and good stability suggesting its usefulness as economic and environmental friendly antibiofilm agents.</p

Neuromorphic liquid marbles with aqueous carbon nanotube cores

Neuromorphic computing devices attempt to emulate features of biological nervous systems through mimicking the properties of synapses, towards implementing the emergent properties of their counterparts, such as learning. Inspired by recent advances in the utilisation of liquid marbles (microlitre quantities of fluid coated in hydrophobic powder) for the creation of unconventional computing devices, we describe the development of liquid marbles with neuromorphic properties through the use of copper coatings and l.0mgml-1 carbon nanotube-containing fluid cores. Experimentation was performed through sandwiching the marbles between two cup-style electrodes and stimulating them with repeated DC pulses at 3.0 V. Our results demonstrate that 'entrainment∗ of a carbon nanotube filled-copper liquid marble via periodic pulses can cause their electrical resistance to rapidly switch between high to low resistance profiles, upon inverting the polarity of stimulation: The reduction in resistance between high and low profiles was approximately 88% after two rounds of entrainment. This effect was found to be reversible through reversion to the original stimulus polarity and was strengthened by repeated experimentation, as evidenced by a mean reduction in time to switching onset of 43%. These effects were not replicated in nanotube solutions not bound inside liquid marbles. Our electrical characterisation also reveals that nanotube-filled liquid marbles exhibit pinched loop hysteresis IV profiles consistent with the description of memristors. We conclude by discussing the applications of this technology to the development of unconventional computing devices and the study of emergent characteristics in biological neural tissue

Development and validation of a reference marker for identification of aerobic and anaerobic bacteria associated with diabetes chronic wound ulcers using PCR denaturing gradient gel electrophoresis

Introduction: Diabetes chronic wounds consist with a diverse microbial community and unculturablespecies may be highly prevalent.Objectives: This study aimed to establish a bacterial reference marker consisting of a group ofchronic wound related bacteria, using polymerase chain reaction-denaturing gradient gelelectrophoresis (PCR-DGGE) for profiling of bacteria in diabetes chronic wound infections.Methods: DNA was extracted from the known wound bacterial strains. PCR–DGGE was performedusing eubacterial specific primers targeting V2-V3 region of 16S rDNA. DGGE was performed usinga 30-55% denaturing gradient. Migration position of each organism was detected on DGGE gel andimportant organisms were selected. Equal volume from PCR products of each selected organism wasmixed, diluted with gel loading dye in 1:1.5 ratio and used for all DGGE gels. The ladder was thensubjected to species identification of fifteen tissue debridement specimens obtained from diabeteschronic wound ulcers. The identification efficacy was tested by sequencing.Results: DNA of bacterial pathogens which showed different migration distances on the gel werecombined and used as a reference panel. This bacterial ladder consisted of eleven different bacterialspecies including Bacteroides sp., S. aureus, Acineto bacter sp., P. aeruginosa, Streptococcus Group Aand Group B sp., E. faecalis, Providencia sp., Veillonella sp., E .coli and Enterobacter sp. Accordingto the reference panel, Pseudomonas species were abundant. Further the results were confirmed bysequencing.Conclusion: Reference marker allows comparative analysis of DGGE patterns and can be used as atool for presumptive identification of polymicrobial microbiota in chronic wound infections

Farmers’ occupational health, perception and practices towards leptospirosis: A cause for concern

Introduction: Leptospirosis is a neglected zoonotic disease with a global distribution. Exposure to Leptospira is a major occupational health concern with farmers. Lack of awareness of disease can result in delay in seeking medical care which has serious implications on morbidity and mortality. This study aimed to assess knowledge, attitudes and practices (KAP) towards leptospirosis among farmers in the district of Colombo, Sri Lanka.Methods: The study was a descriptive, cross sectional study conducted among farmers in the district of Colombo, Sri Lanka. Data was collected using a pre-tested interviewer-administered questionnaire to assess the KAP of 120 randomly selected farmers in the Homagama, Padukka, Boralesgamuwa and Kotte Medical Officer of Health (MOH) areas.Results: The majority of respondents were in the 50-74 year age group and 85% were male. The majority of participants had reasonable knowledge (74%) of the method of transmission, symptoms, complications and preventive measures of leptospirosis, which was occupationally related to farming. Satisfactory attitudes towards disease prevention was demonstrated by 92.5% and 53.3% had favorable practices.Conclusion: The results of the study imply that knowledge of leptospirosis among the farming community can be improved further. This in turn may help to translate toward better attitudes and practices.</p

Influence of culture medium on in-vitro biofilm formation by Candida species

Objectives: Objective of this study was to establish an in vitro biofilm on the 96 well plates and to determine the efficacy of three different culture media on biofilm formation of Candida albicans and C. tropicalis Methods: A 96 well sterile, polystyrene plate was inoculated using 10^6 cell/ml of C. albicans and C. tropicalis suspensions and the growth rate of planktonic cells was determined by measuring the absorbance (OD492) at 2 hour intervals. Adhesion of Candidial cells to initiate the biofilm formation in the presence of three culture media (Yeast Nitrogen Base (YNB) supplemented with 100 mM glucose, Sabouraud Dextrose Broth (SDB) and RPMI1640) was quantified using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and Crystal Violet (CV) assay after 90 minutes. Biofilms of C. albicans, C. tropicalis and 1:1 co-biofilms were developed and the growth rates were quantified at 24 hours’ time intervals. Scanning electron microscope (SEM) was performed to assess the architecture. Results: Planktonic cells of both C. albicans and C. tropicalis showed maximum growth with SDB. C. albicans and co-biofilm adhesion were significantly facilitated with RPMI1640 and the best medium for C. tropicalis adhesion was YNB. Biofilms showed the maximum growth rate in RPMI 1640. C. tropicalis exhibited the minimum growth with all three culture media.Conclusions: The maximum growth rate for planktonic C. albicans and C. tropicalis was achieved with SDB. However RPMI 1640 was the best medium for growth of biofilms