Controlling the size distribution of nanoparticles through the use of physical boundaries during laser ablation in liquids

A simple, yet effective method of controlling the size and size distributions of nanoparticles produced as a result of laser ablation of target material is presented. The method employs the presence of physical boundaries on either sides of the ablation site. In order to demonstrate the potential of the method, experiments have been conducted with copper and titanium as the target materials that are placed in two different liquid media (water and isopropyl alcohol). The ablation of the target material immersed in the liquid medium has been carried out using an Nd:YAG laser. Significant differences in the size and size distributions are observed in the cases of nanoparticles produced with and without confining boundaries. It is seen that for any given liquid medium and the target material, the mean size of the nanoparticles obtained with the boundary-fitted target surface is consistently higher than that achieved in the case of open (flat) targets. The observed trend has been attributed to the plausible role(s) of the confining boundaries in prolonging the thermalisation time of the plasma plume. In order to ascertain that the observed differences in sizes of the nanoparticles produced with and without the presence of the physical barriers are predominantly because of the prolonged thermalisation of the plasma plume and not due to the possible formation of oxide layer, select experiments with gold as the target material in water have also been performed. The experiments also show that, irrespective of the liquid medium, the increase in the mean size of the copper-based nanoparticles due to the presence of physical boundaries is relatively higher than that observed in the case of titanium target material under similar experimental conditions.Comment: 24 pages, 9 figures, a part of this work has been published in Photonics Prague 2017, (Proc. SPIE 10603, Photonics, Devices, and Systems VII, 1060304) titled "A novel method for fabrication of size-controlled metallic nanoparticles

Voltage to Frequency Converter: Modeling and Design

In this thesis a study on conventional voltage to frequency converter is given. A linear voltage to frequency converter is assumed i.e. the output frequency level changes with the varying input voltage level. Then as per the findings of our study a voltage to frequency converter is designed and a physical model of the designed circuit is prepared. A transformer and full wave rectifier are used to reach the optimal dc voltage level while the regulator is used for controlled power supply. An op-Amp based voltage to frequency converter is designed whose output is obtained through a 555 timer. The main operation of the op-Amp is to serve as a voltage integrator which is necessary for triangular wave generation and also as a comparator for converting the triangular wave into square wave. The timer circuit is operated in monostable mode. A simple and low cost voltage to frequency converter design and its performance analysis is the main objective of this thesis

Effect of dietary chitosan on haematology, innate immunity and disease resistance of Asian seabass Lates calcarifer (Bloch).

This study was performed to evaluate the effect of dietary chitosan on haematology, innate immunity and protection against Vibrio anguillarum in Asian seabass, Lates calcarifer. A basal diet supplemented with 0, 5, 10 and 20 g chitosan kg−1 diet was fed to the four different groups for 60 days. The haematological (total erythrocyte count, total leucocyte count, total serum protein, albumin, globulin and albumin‐globulin ratio) and innate immune parameters (phagocytic ratio, respiratory burst, serum lysozyme and serum bactericidal activities) were monitored at fortnight interval to assess the effect of chitosan feeding in Asian seabass. All the studied haematological and innate immune parameters were increased significantly (P ≤ 0.05) in chitosan‐fed groups in comparison with control. However, the group fed diet containing 10 g chitosan Kg−1 feed showed highest haematological and innate immune parameters on 45th day in comparison with other groups. Moreover, the fish fed the diet containing 10 g chitosan Kg−1 feed had significantly higher post‐challenge survival (75.56 ± 4.44%) on the 30th day following V. anguillarum challenge. Therefore, this study suggests that chitosan at 10 g kg−1 diet could be used as prophylactic in Asian seabass culture to enhance the protection against any possible infection by V. anguillarum

Assessing data quality in survey with healthcare providers on COVID-19 and the measures for improving

Background: Social surveys have also been transformed with the advancements in research methods. However, only through appropriate methods, proper planning and procedures the data quality can be ensured.Aim: The aim of the current research is to present the measures taken up in doing survey with healthcare providers of primary health care facilities during the time of COVID-19 and to assess the data quality.Method: The survey was conducted with all 280 medical and paramedical staff in 24 primary healthcare centers of government to understand the preparedness of primary health care facilities in terms of providing a safe working environment to healthcare providers and to prevent the spread of infection while discharging duties during COVID-19. The study used mix mode of data collection by administering telephonic and self-administered questionnaire.  It is a descriptive study based on review of secondary literature and the different measures adopted in the survey to ensure data quality.Result: The variation found in responses to questions related to training, personal fears, challenges and coping mechanism was low, when asked differently in telephonic and self-administered questionnaire. It shows that the measures taken in conducting survey through mix mode of data collection at the time of COVID-19 were effective in overcoming the data quality challenges of COVID-19 to conduct face-to-face study and maintaining data quality of the survey.Conclusion: It can be concluded that proper planning, preparations and precautions were effective in ascertaining the data quality

Mechanical characterization of animal fibre-based composites

293-297Horsehair-based composites have been prepared by reinforcing polylactic acid (PLA) using hot compression molding. The weight fraction of horsehair fibre in composites has been varied from 0% to 30 wt.% to investigate the effect of fibre loading on the mechanical properties and moisture absorption performance of the developed composites. The mechanical properties, such as strength and modulus (tensile and flexural), impact energy, and moisture absorption behaviour of the fabricated composites, are experimentally evaluated. The experimental results recommend that the composites reinforced with 20 wt.% horsehair exhibit superior mechanical properties as compared to other developed composites. The tensile strength and modulus, flexural strength and modulus, Charpy and Izod impact energy of the composites reinforced with 20 wt.% horsehair are improved by 9.52, 28.74, 7, 5.63, 398.11 and 379.31% as compared to, one-on-one, neat PLA. The findings also reveal that the percentage of moisture absorption of the developed composites increases with an increase in the fibre content in the developed composites

Bilateral Asymmetric Dislocations of Hip Joints: An Unusual Mechanism of Injury

Asymmetric bilateral dislocations of the hips are rare injuries. Among the small number of reports in the literature, most have attributed the cause to high-velocity motor crashes. These dislocations are often seen to be associated with fractures of the proximal femur or the acetabulum. We present a case of a 45-year-old man with bilateral asymmetric dislocation of hips which were purely ligamentous in nature, without any fracture. He sustained his injuries due to a fall while getting on a moving bus. It was an unusual mechanism of injury as compared to the other cases of asymmetric hip dislocations reported in published studies. Both hips were reduced under general anaesthesia within three hours of the trauma. Skin traction and non-weight-bearing rehabilitation were continued for six weeks. After 35 months of followup, the patient remains asymptomatic. Early diagnosis and timely reduction of such dislocations under anaesthesia are necessary for prevention of complications

Mechanical characterization of animal fibre-based composites

Horsehair-based composites have been prepared by reinforcing polylactic acid (PLA) using hot compression molding. The weight fraction of horsehair fibre in composites has been varied from 0% to 30 wt.% to investigate the effect of fibre loading on the mechanical properties and moisture absorption performance of the developed composites. The mechanical properties, such as strength and modulus (tensile and flexural), impact energy, and moisture absorption behaviour of the fabricated composites, are experimentally evaluated. The experimental results recommend that the composites reinforced with 20 wt.% horsehair exhibit superior mechanical properties as compared to other developed composites. The tensile strength and modulus, flexural strength and modulus, Charpy and Izod impact energy of the composites reinforced with 20 wt.% horsehair are improved by 9.52, 28.74, 7, 5.63, 398.11 and 379.31% as compared to, one-on-one, neat PLA. The findings also reveal that the percentage of moisture absorption of the developed composites increases with an increase in the fibre content in the developed composites.

Agroforestry practices for physiological amelioration of salt aff ected soils

Agroforestry is a sustainable land use system act as an alternative form of biological reclamation in salt affected soils apart from sustainable production, continuous income, and regular employment along with food and nutrition security. In general, salt affected soils get ameliorated by tree species; however, following factors such as nature and type of tree species planted, growth habit, quantity and quality of litter production, planting density, nitrogen fixation, and different management practices are influenced. In the present study, various studies pertaining to soil reclamation in the salt affected soils are reviewed. Overall result showed that trees grown with crops, horticultural crops, pastures resulted in improvement of physical and chemical properties of soil under various agroforestry systems. For instance, reduction of soil pH, electrical conductivity, and exchangeable sodium percentage minimization of salt deposition in the upper layers of the soil, improvement of water permeability and water holding capacity, improvement of infiltration rate and hydraulic conductivity with soil fertility, enhancement of cation exchange capacity, and other features are characteristics of soil as influenced by tree species, as well as through agroforestry practices. Various multipurpose tree species such as Acacia auriculiformis, Acacia nilotica, Albizia lebbeck, Terminalia arjuna, Casuarina equisetifolia, Prosopis cineraria, Prosopis juliflora; and fruit trees such as Zizyphus jujuba, Emblica officinalis, Syzygium cumini, and Tamarindus indica ameliorated the different salt affected soils in different agroforestry systems viz., agrisilvicultural system, silvipastoral system, multipurpose wood lot, and agrihorisilvicultural system. Thus, agroforestry system provides an alternative for restoring soil health and amelioration of salt affected soils for further yield improvement. Therefore, these species are suggested for reclamation of salt affected soil through agroforestry systems

Deltamethrin induced alterations of hematological and biochemical parameters in fingerlings of Catla catla (Ham.) and their amelioration by dietary supplement of vitamin C

The present study was carried out to investigate the sub-lethal toxicity of technical grade deltamethrin (a synthetic pyrethroid) of concentration 1.61 μg/L (1/3rd of 96 h LC50) on hematological and biochemical parameters of catla (Catla catla) fingerlings and its amelioration through dietary vitamin C. The deltamethrin exposed fishes were fed with different levels of supplemented vitamin C such as 50, 250, 500 and 1000 mg/kg diet to see its ameliorating effect by assaying hematological parameters viz. total erythrocyte count (TEC), total leukocyte count (TLC), hemoglobin content (Hb), total serum protein, albumin, globulin, albumin–globulin ratio and biochemical parameters such as lactate dehydrogenase (LDH), acetylcholine esterase (AChE), alanine amino transferase (ALT), aspartate amino transferase (AST), total adenosine triphosphatase (ATPase), magnesium adenosine triphosphatase (Mg2+-ATPase) and sodium potassium adenosine triphosphatase (Na+, K+-ATPase) activities. The finding of this study showed that deltamethrin had negative effect on the hematological and biochemical parameters of Catla catla. The experimental group, which was exposed to deltamethrin and fed with normal diet showed significantly lower values (P ⩽ 0.05) of all parameters studied except ALT activity. This might be due to possible disruption of hematopoiesis and proteosynthesis. However, the fish fed with varied concentration of vitamin C in diets neutralized the toxic effect of deltamethrin, as evidenced by significantly lowered hematological and biochemical response. Vitamin C @ 1000 mg/kg diet was the most effective in amelioration of harmful effect of deltamethrin on hematological and biochemical parameters of catla fingerlings. The result suggests that vitamin C can be effectively used to neutralize the toxic effect of deltamethrin on catla