Artificially Disordered Birefringent Optical Fibers

We develop and experimentally verify a theory of evolution of polarization in artificially-disordered multi-mode optical fibers. Starting with a microscopic model of photo-induced index change, we obtain the first and second order statistics of the dielectric tensor in a Ge-doped fiber, where a volume disorder is intentionally inscribed via UV radiation transmitted through a diffuser. A hybrid coupled-power & coupled-mode theory is developed to describe the transient process of de-polarization of light launched into such a fiber. After certain characteristic distance, the power is predicted to be equally distributed over all co-propagating modes of the fiber regardless of their polarization. Polarization-resolved experiments, confirm the predicted evolution of the state of polarization. Complete mode mixing in a segment of fiber as short as ~ 10cm after 3.6dB insertion loss is experimentally observed. Equal excitation of all modes in such a multi-mode fiber creates the conditions to maximize the information capacity of the system under e.g. multiple-input-multiple-output (MIMO) transmission setup

The effect of an infra-acetabular screw for anatomically shaped three-dimensional plate or standard plate designs in acetabulum fractures: a biomechanical analysis

Background Various plate shapes and implant configurations are used for stabilization of acetabulum fractures via anterior approaches. Little is known about the biomechanical stability of a two-dimensionally shaped “conventional” plate (“J-Plate”—JP) in comparison to three-dimensionally shaped plate configurations (3DP). In addition, the augmentary effect of an infra-acetabular lag-screw (IACS) fixation for anterior column and posterior hemi-transverse acetabulum fractures has not been clarified in comparison of JP and 3DP constructs. This study analyzed the difference between the biomechanical stability of JP compared to 3DP and the role of an IACS in a standardized acetabular fracture model in a single-leg stance loading configuration. Methods In an artificial bone substitute pelvis model (Synbone© Malans, Switzerland), a typical and standardized fracture pattern (anterior column and posterior hemi-transverse) was created with osteotomy jigs. After anatomic reduction the stabilization was performed using JP or 3DP. Eight pelvises per group were axially loaded in a single-leg stance model up to 400 N. After the load cycle, an additional infra-acetabular screw was placed and the measurement repeated. Fragment displacement was recorded by an optical tracking system (Optitrack Prime 13®, Corvallis, USA). Results In the pure placement, 3DP provided significantly superior stability when compared to JP. Augmentation of JP by IACS increased the stability significantly, up to the level of 3DP alone, whereas augmentation of the 3DP did not result in further increase of overall stability. Conclusion The anatomically shaped plate alone provides a superior biomechanical stability in fixation of an anterior column and posterior hemi-transverse fracture model. In a JP fixation the augmentation by IACS provides similar strength as the anatomically shaped 3DP. By use of the anatomically shaped 3DP the need of a clinically risky application of IACS might be avoidable

Biochemical expression of exudes of a fungal-bacterial bio film during growth and maturation

Biofilms are often complex communities of multiple microbial species and remain attached to surfaces. Fungal-bacterial biofllms are formed when the fungal surface is colonized by one or more species of bacteria. These biofilms can enhance microbial effectiveness compared to the monocultures. Beneficial biofilms can be developed in vitro and be used for various agricultural and biotechnological purposes. As a recent development in biofertilizer research, fungal-rhizobial biofilms have been developed and these are termed biofilmed biofertilizers (BFBFs). This research was focused to investigate chemical composition of compounds exuded during growth and maturation of the biofilms. A developed fungal-bacterial biofilm using an Azotobacter species and a Colletorichum fungal species was used for the study. Exudates of the biofilm, fungal monoculture and bacterial monoculture in solid and liquid states were extracted separately by using three organic solvents; hexane, ethyl acetate and methanol. Extraction was done weekly for four weeks during growth and maturation of the biofllm. Then extracted exudates dissolved in organic solvents were evaporated by using a vortex evaporator. Thereafter crude was mixed with potassium bromide (KBr) and pellets were made. The KBr pellets were analyzed using Fourier Transform Infrared (FTIR) spectroscopy. To evaluate the effect of the exudates of the fungal-bacterial biofilm on seed germination and plant growth in comparison to bacterial and fungal monocultures, a plant assay was done weekly by using lettuce (Lactuca sativa) seeds (N 48). During all four harvests, the fungal-bacterial biofllm produced more diverse functional groups than the mono cultures. The developed biofilm produced carboxylic acids and carboxylic salts, which are associated with plant growth promoting hormones, especially in first and second harvests. Significantly higher plant height and high germination of lettuce with the biofilm exudates could be attributed to above fact. During third and fourth weeks, the biofllm produced more amines and amides than fungal and bacterial mono cultures. This may have contributed to increased pH in biofilm cultures compared to the mono cultures. Thus, it can be concluded that biochemical expression of exudates of fungal-bacterial biofilms during their growth and maturation is very useful for breaking dormancy of seeds and their germination and growth, contributing to high plant productivit

Hydro-Meteorological Disaster Incidents and Associated Weather Systems in Sri Lanka

This paper presents a comprehensive seasonal analysis of disaster incidents with their associated weather systems happened in Sri Lanka since 1907 to 2019. Disaster incidents and weather records were collected from different reliable sources and analysed with the observed weather systems to understand the formation and development of the weather systems. According to the observations, frequent hydro-meteorological hazards experienced by the country are extreme winds, floods, and landslides. The seasonal analysis shows that majority of these hydro-meteorological disasters have occurred during the southwest monsoon, where the weather was mainly dominated by the monsoon winds entering from the southwest of Sri Lanka which creates torrential rainfall mainly in the wet zone of the country. The frequency of formation of depression and deep depression, from 1907 to 2019 shows that most of these are formed in the Bay of Bengal (BoB), North Indian Ocean, from October to January while having the highest frequency in November followed by December. The study will help to understand the possible damages, and thereby help the community to be prepared for such future hazards. The need for a central platform for generating timely impact-based warnings and helping the community to act was also identified. Further, the census block can be suggested as the smallest; Micro-Geographic Incident Response Unit (MG-IRU) to grant the decision-making power and connect the institution and community in the disaster risk management process.</p

Expression of genes associated with immunity in the endometrium of cattle with disparate postpartum uterine disease and fertility.

BACKGROUND: Contamination of the uterine lumen with bacteria is ubiquitous in cattle after parturition. Some animals develop endometritis and have reduced fertility but others have no uterine disease and readily conceive. The present study tested the hypothesis that postpartum cattle that develop persistent endometritis and infertility are unable to limit the inflammatory response to uterine bacterial infection. METHODS: Endometrial biopsies were collected several times during the postpartum period from animals that were subsequently infertile with persistent endometritis (n = 4) or had no clinical disease and conceived to first insemination (n = 4). Quantitative PCR was used to determine the expression of candidate genes in the endometrial biopsies, including the Toll-like receptor (TLR 1 to 10) family of innate immune receptors, inflammatory mediators and their cognate receptors. Selected proteins were examined by immunohistochemistry. RESULTS: The expression of genes encoding pro-inflammatory mediators such as interleukins (IL1A, IL1B and IL6), and nitric oxide synthase 2 (NOS2) were higher during the first week post partum than subsequently. During the first week post partum, there was higher gene expression in infertile than fertile animals of TLR4, the receptor for bacterial lipopolysaccharide, and the pro-inflammatory cytokines IL1A and IL1B, and their receptor IL1R2. The expression of genes encoding other Toll-like receptors, transforming growth factor beta receptor 1 (TGFBR1) or prostaglandin E2 receptors (PTGER2 and PTGER4) did not differ significantly between the animal groups. Gene expression did not differ significantly between infertile and fertile animals after the first week postpartum. However, there were higher ratios of IL1A or IL1B mRNA to the anti-inflammatory cytokine IL10, during the first week post partum in the infertile than fertile animals, and the protein products of these genes were mainly localised to the epithelium of the endometrium. CONCLUSION: Cattle may maintain fertility by limiting the inflammatory response to postpartum bacterial infection in the endometrium during the first week after parturition.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Knowledge, Perception and Practices Regarding COVID-19 among frontline Nurses at Selected hospitals in Sri Lanka during COVID-19 Pandemic

Introduction: The World Health Organization confirmed the COVID-19 epidemic situation as a public health emergency and is an emerging public health problem that has threatened millions of lives worldwide. Since COVID-19 has significantly affected the healthcare system globally, it is essential to update healthcare workers especially frontline nurses on the best practices for the proper management of the disease. The study aimed to assess Knowledge, Perceptions, and Practices regarding COVID-19 among frontline nurses at the National Institute of Infectious Diseases, National Hospital of Sri Lanka, and Base Hospital Mawanella in Sri Lanka. Methods: This cross-sectional study was conducted among 257 frontline nurses from main three hospitals in Sri Lanka from June 2020 to December 2021. A validated, pre-tested self-administered questionnaire was used for data collection. Kruskal Wallis test and Chi-square test were applied to find significant factors associated with good knowledge, using SPSS version 25. Results: The average age of the 257 participants was (31.8 ± 6.6) years and most (95%) of them were female. Of them, 79.4% had good knowledge, and the knowledge level of the nurses was significantly associated with their marital status (p=0.04) and their participation in the COVID-19 management workshop or lecture (p ≤0.001). There was a statistically significant median score difference between participants’ knowledge, and three hospitals (p<0.05). Conclusion: The findings demonstrated that the nurses had overall good knowledge, positive perception, and good practice on COVID-19. This study highlighted the factors influencing knowledge about COVID-19 that must be addressed in future education, awareness, and preparing the programs

China’s rising hydropower demand challenges water sector

Demand for hydropower is increasing, yet the water footprints (WFs) of reservoirs and hydropower, and their contributions to water scarcity, are poorly understood. Here, we calculate reservoir WFs (freshwater that evaporates from reservoirs) and hydropower WFs (the WF of hydroelectricity) in China based on data from 875 representative reservoirs (209 with power plants). In 2010, the reservoir WF totaled 27.9 × 109 m3 (Gm3), or 22% of China’s total water consumption. Ignoring the reservoir WF seriously underestimates human water appropriation. The reservoir WF associated with industrial, domestic and agricultural WFs caused water scarcity in 6 of the 10 major Chinese river basins from 2 to 12 months annually. The hydropower WF was 6.6 Gm3 yr−1 or 3.6 m3 of water to produce a GJ (109 J) of electricity. Hydropower is a water intensive energy carrier. As a response to global climate change, the Chinese government has promoted a further increase in hydropower energy by 70% by 2020 compared to 2012. This energy policy imposes pressure on available freshwater resources and increases water scarcity. The water-energy nexus requires strategic and coordinated implementations of hydropower development among geographical regions, as well as trade-off analysis between rising energy demand and water use sustainability