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Background: The assessment of antibody responses to severe acute respiratory syndrome coronavirus-2 is potentially confounded by exposures to flaviviruses. The aims of the present research were to determine whether anti-dengue antibodies affect the viral load and the detection of anti-coronavirus nucleocapsid (N)-protein antibodies in coronavirus infectious disease 2019 (COVID-19) in Bangladesh. Methods: Viral RNA was evaluated in swab specimens from 115 COVID-19 patients by real-time reverse transcription polymerase chain reaction (rT-PCR). The anti-N-protein antibodies, anti-dengue virus E-protein antibodies and the dengue non-structural protein-1 were determined in serum from 115 COVID-19 patients, 30 acute dengue fever pre-COVID-19 pandemic and nine normal controls by ELISA. Results: The concentrations of viral RNA in the nasopharyngeal, Ct median (95% CI), 22 (21.9–23.3) was significantly higher than viral RNA concentrations in oropharyngeal swabs, and 29 (27–30.5) p &lt, 0.0001. Viral RNA concentrations were not correlated with-dengue IgG levels. The anti-nucleocapsid antibodies were IgA 27% positive and IgG 35% positive at days 1 to 8 post-onset of COVID-19 symptoms versus IgA 0% and IgG 0% in dengue patients, p &lt, 0.0001. The levels of anti- nucleocapsid IgA or IgG versus the levels of anti-dengue IgM or IgG revealed no significant correlations. Conclusions: Viral RNA and anti-nucleocapsid antibodies were detected in COVID-19 patients from dengue-endemic regions of Bangladesh, independently of the dengue IgG levels.

Worldwide Climate change is a challenging issue for every sector from business to agriculture or society. Tourism is not exempt from the adversity of Climate Change impact in a disaster-prone country like Bangladesh. Tourism could be regarded as a worst victim to Climate Change and it contributes to global Climate Change as well. However, the chapter outlays the Climate Change impact on tourism in Bangladesh and potential tackling strategies for sustainable tourism development of the country. A thorough systematic review has been done based on peer reviewed journals, reports of tourism policy makers or civil society dialogues to outline potential adaptation strategies that could be implanted by the tourism industries or stakeholders of Bangladesh to make it more sustainable. Though tourism industry of Bangladesh is still lagging behind than the neighboring countries, it is high time to adopt the strategies generated from both primary and secondary sources of data. To observe Climate Change impact thermal images had been analyzed of top tourist destination of Bangladesh and temperature data had been investigated for analysis based on the climatic data collected from the Bangladesh Meteorological Department. Other resources also show same evidence that climate change is bringing about temperature rise, beach erosion, uneven precipitation rate and salinity intrusion in the country. Finally, after identifying probable impacts on tourism because of Climate Change, adaptation measures have been suggested widely. Thus, there is always scope for further research to develop tourism sector is a sustainable manner and combat with the Climate Change adversity.

Background and objectives: Leptospirosis is a zoonotic infection with worldwide distribution caused by the Leptospira species and predominant in the tropical and subtropical regions. Information on leptospirosis in Bangladesh is limited. The present study was designed to detect anti-leptospiral antibodies in human serum samples in Bangladeshi population by developing an in-house ELISA using recombinant LipL32 (rLipL32) antigen. The study was conducted from April 2014 to December 2014.Method: Healthy individuals from two rural areas and fever cases from one urban healthcare center were enrolled in the study. Rural health centers were located at Sonargoan and Bajitpur sub-district (Upozilla) of Narayaganj and Kishorganj districts. Sonargoan health center is located 26 km south-east and Bajitpur is located 71 km north-east of Dhaka city. About 1-2 ml of blood was collected with aseptic measure and serum was separated and stored at -200C until used. Anti-leptospiral IgG antibody was determined by recombinant LipL32 (rLipL32) antigen based indirect enzyme linked immunosorbent assay (ELISA). Seropositive cases were further confirmed by commercial Leptospira IgG ELISA.Results: The study included 250 febrile cases and 376 healthy individuals from urban and rural areas, respectively. Out of total 626 study population, anti-LipL32 specific IgG antibody was detected in 70 individuals (11.2%). The rate of positivity of anti-LipL32 antibody among the healthy individuals from rural area was 10.6% while the rate was 12.0% in urban febrile population. The rate of positivity in rural and urban population was not significantly (p>0.05) different. Among the urban population, the rate of seropositivity was 9.1% and 16.4% in 21- 40 yrs and above 40 years age group respectively while the rate was 7.2% and 14.0% in rural population respectively. Out of 70 seropositive cases detected by LipL32 ELISA, 65 (92.9%) were positive by commercial ELISA.Conclusion: The present study has revealed that leptospirosis is prevalent in Bangladesh and should be looked for in febrile and clinically suspected cases. The study has also demonstrated that rLipL32 protein may be used as a candidate antigen for the serodiagnosis of leptospirosis.IMC J Med Sci 2017; 11(2): 50-55

We have investigated the simulation approach of a one-dimensional online simulator named A Device Emulation Program and Tool ( ADEPT 2.1 ) and the device performances of a thin film solar cell based on Cu 2 ZnSn ( S,Se ) 4 ( CZTSSe ) absorber have been measured. Initiating with a thin film photovoltaic device structure consisting of n-ZnO : Al / i-ZnO / Zn 1 - x Sn x O y ( ZTO ) / CZTSSe / Mo / SLG stack, a graded space charge region ( SCR ) and an inverted surface layer ( ISL ) were inserted between the buffer and the absorber. The cadmium ( Cd ) free ZTO buffer, a competitive substitute to the CdS buffer, significantly contributes to improve the open-circuit voltage, V oc without deteriorating the short-circuit current density, J sc . The optimized solar cell performance parameters including V oc , J sc , fill factor ( FF ) , and efficiency ( η ) were calculated from the current density-voltage curve, also known as J – V characteristic curve. The FF was determined as 73.17 % , which in turns, yields a higher energy conversion efficiency of 14.09 % .

Bangladesh is a land of natural beauty with hilly mountains, rivers, lakes. The beauties of Bangladesh have attracted both local and foreign people. To make proper utilization of the scenic beauty tourism industry has been established in Government and Private sector. The objective of the study is to find out the involvement of Private sector in tourism industry in Bangladesh. Questionnaire has been constructed based on several parameters to take feedback from respondents. A conceptual model has been developed to judge the satisfaction level of the tourists. Likert scale test, Alpha test for reliability, descriptive statistics, correlation analysis, regression analysis have been conducted. Likert test result shows higher reliability of questionnaire constructed. Correlation showed positive relationship between independent and dependent variables and regression result showed significant satisfaction level of respondents on the involvement of private sector in tourism industry. Null hypothesis is rejected which means respondents opinion is positive in terms of involvement of private sector in tourism industry. Overall it can be said that involvement of both Private and Public sector can ensure smooth operation of tourism industry and provide the needed support to tourists, which will also ensure economic growth and stability.

Handwritten character recognition is one of the most emerging fields within the optical character recognition area. Bangla handwritten character recognition is a complex task, it is challenging due to extensive size and diversity within the alphabets. Currently, convolutional neural network (CNN) has been proven to have the ability to classify complex dataset. The convolutional neural network does not require any predefined feature extraction method, but it requires a large dataset to gain accuracy. This work proposes a convolutional neural network model for classifying Bangla handwritten alphabets and compares the performance with the other widely used models for classification. Each model is trained with a large dataset, which is augmented to have diversity in data and features. After training, we have tested the models with 7500 sample images and it shows an accuracy of 97.87% for the proposed model. In this work, we also find out the weights of the CNN network for best performance and used that weights to evaluate the performance from other data set for cross-validation of our model. The weighted model accuracy for two different independent data set is 95.23% and 94.22%.

Nuclear Medicine workers are getting higher radiation dose because of increasing usage of nuclear medicine for diagnostic and therapeutic procedures. The purpose of the study is to monitor the real-time radiation at the indoor places of the Institute of Nuclear Medicine & Allied Sciences (INMAS) Mitford, Sir Salimullah Medical College and Hospital Campus for minimizing the ionizing radiation hazard to radiation worker and public. The radiation monitoring was performed using real-time portable digital radiation monitoring device. This real-time digital portable radiation monitoring device meets all European CE standards as well as the American “FCC 15 standard”. The portable radiation monitoring device was placed at 1 meter above the ground on tripod and data acquisition time for each monitoring point (MP) was 1 hour. 26 MPs were selected for collection of radiation dose rates at different indoor locations of INMAS, Mitford hospital. The measured dose rates due to natural and man-made radionuclides were ranged from 0.151 ± 0.070 μSv.h-1 to 4.313 ± 1.829 μSv.h-1 with an average of 0.456 ± 0.227 μSv.h-1. The annual effective dose to the radiation worker and public due to radiation were varied from 0.305 mSv to 8.764 mSv with an average of 0.951 mSv. Excess life-time cancer risk factor based on annual effective dose to radiation worker and public were calculated and varied from 1.213 Χ 10-3 to 3.486 Χ 10-2. Real-time radiation monitoring at indoor places of nuclear medicine facilities are required for minimizing unnecessary exposure to nuclear medicine workers and public from man-made sources. This kind of study is required for minimizing the radiation hazard in the hospital environment and consequently to keep the radiation dose to worker and public as low as possible.

Traffic congestion severely affects many cities around the world causing various problems like fuel wastage, increased stress levels, delayed deliveries and monetary losses. Therefore, it is urgent to make an accurate prediction of traffic jams to minimize these losses. But forecasting is a real challenge to obtain promising results for vibrant and ambiguous traffic flows in urban networks. This paper proposes a new traffic jam prediction model using pre-calculated density from node information table based on previous traffic data. In this model, we predicted traffic congestion of an intersection according to its adjacent road's node information table, where node information table contains the traffic density of all incoming lanes of an intersection (node). Besides, for this model, we consider all intersections of a city as individual nodes, and we prepare node information table for each node. Our work can be divided into two parts: (1) we perform time series analysis on previous data of a node and its adjacent nodes, and (2) then apply those calculated values to this model and make the prediction based on it. The forecasted value will always be between 0 and 1. Where 0 means no traffic congestion, close to 0 means low traffic congestion and 1 means heavy traffic or close to 1 means congested traffic lane, accordingly.

Background and objective: This study focused on the analysis and comparison of humoral immune response to Mycobacterium tuberculosis (MTB) cell wall fraction (CWF) and lipoarabinomannan (LAM) antigens. Methods: Sera from adult patients with active pulmonary tuberculosis and age and sex matched healthy individuals were tested for immunoglobulin (Ig) M and IgG antibodies to CWF and LAM by enzyme linked immunosorbent assay (ELISA). Results: The mean OD values of serum IgM and IgG antibodies against CWF of TB patients was not significantly (p=0.52, p=0.45) different from that of healthy control population. However, the mean OD values of serum IgM and IgG against LAM were significantly (p=0.049, p= 0.001) higher in TB cases than that of healthy individuals. Conclusion: The present study has revealed that IgM and IgG antibody to LAM may be used in serodiagnosis of TB while response to CWF in active TB case is restricted in our population. IMC J Med Sci 2016; 10(2): 58-60

Monitoring of air quality is becoming more and more important day by day due to significant impacts of air pollution on public health, global atmosphere, and worldwide economy. With the continuous development of the Internet of Things (IoT) is becoming progressively more important for air monitoring, traffic monitoring, smart home control, smart parking management and other industrial and home applications. A real-time air monitoring system is essential for Bangladesh because of gas leak-related incidents and other types of phenomena especially for Dhaka city. In this paper, we propose a smart real time Air Monitoring System with emergency alert based on Internet of Things (IoT), which allows users to track the surrounding air quality of their home or office or industries from anywhere. An alarm goes to user of the system in case of any emergency life threatening situation.

Film is the wonderful industry and powerful organ of mass media in the present world. This unique mass media becomes the container and carrier of society, civilization, history, tradition and culture. It is equally popular in Bangladesh, like other countries. In 1895,Lumiere Brothers son of Antoa Lumiere invented cinematograph with the combinations of camera and projector. On 28 December in 1895 they showed the first cinema by the cinematograph. This date is the red-letter day in the history of cinema. Hira Lal Sen was the first film shower and maker in the history of film in Bengal and also in undivided India. He formed a company which was named as The Royal Bioskop Company in 1898. He arranged the first film show in the then East Bengal (now Bangladesh) on 4th April 1898, in Bhola of Barishal. After the War of Independence, Bangladesh started to making film for commercial purposes. This study is conducted to find out the history of film business in Bangladesh. Film making is very expensive which is made in any studio, now it establishes as film industry, so it was made and showed for commercial purpose from it’s birth.

The study gives a brief overview of the field of Bangladesh LaborLlaw-2006 & Bangladesh Labor Law (Amendment)-2013, Labor relations, labor rights, wages and the important issues associated with it. It analyses from the present perspective of both the management and employees, the merits of trade unionism and also the negative consequences of trade unionism have been mentioned. Besides these, the contract negotiation tactics and preparations essential to the management have been briefly discussed. The study also deals with the labor relations practices in the Ready Made Garments (RMG) industry of Bangladesh and the extent of implementation of labor laws in the same industry. The consequences of these have been analyzed using both primary and secondary data collected from trustworthy sources.

Information technology is becoming an important factor in the future development of financial services industry, especially the banking industry. The banking sector is based on sharing of information, which itself heavily relies on information and communication technology (ICT) in order to acquire, analyze and deliver data to all relevant users. The ICT is crucial not only for information analysis, but also enables the banking sector to differentiate its offer from competitors and thereby make it a market leader. In this context, banking sector are obliged to continuously innovate and update their marketing strategies in order to closely meet the demands and the requirements of the individual customers. It also provides safe and confidential services which best suit customers’ needs. The customer wants more flexibility without paying more, and his demands are clear: Make transactions wherever, whenever, and however he wants. Hence ,the development of the concept of electronic financial services, more commonly known as E-banking. At present, private & public banks of Bangladesh have taken various steps in E-banking. This work has been conducted from the secondary data maximally. This article has drawn present trend & development of E-banking in Bangladesh and included conclusion & recommendation.

With the emergence of new technology and innovations, people are searching smarter ways to protect/monitor their properties remotely. In accordance to that, at present GPS based tracking system is frequently used in vehicle tracking, children/pet tracking, aircraft tracking, any personal belongings tracking, fleet management and so on. This paper introduces a Smart Anti-Theft Vehicle System based on Internet of Things (IoT) for monitoring the movement of any equipped vehicle from anywhere in real time. At the implementation of this system, Global Positioning System (GPS), Global System for Mobile Communication (GSM)/General Packet Radio Service (GPRS) and Microcontrollers are used to enable users for monitoring their vehicles in a convenient manner. This system provides the access to check the movement and control (emergency stop by closing the fuel line) vehicles remotely by using mobile application. The hardware prototype of the proposed system and the user application for monitoring and controlling vehicles are presented in this paper.

communication has been going through major changes throughout the last decades. While wireless technologies have been widely adopted, various domains and implementations like wireless sensor Networks (WSN), mobile ad-hoc networks (MANETs), wireless mesh networks have emerged. Since TCP/IP was a protocol designed for wired networks, wireless transmission poses unique challenges to the well-defined and rigid protocol stack. The well-known layers of the OSI model or its practical counterpart TCP/IP model were too strict in some cases to provide with all the services necessitated by these new domains. These issues make way to cross-layer design where the traditional boundaries among layers are violated in different ways to achieve performance gain. In this paper, we gather the motivation behind the cross-layer design, illustrate some representative examples and draw conclusions for the future challenges.

Nosocomial infection is an endemic problem encountered in hospitalized patients all over the world including Bangladesh. The present prospective study was carried out on 152 patients who were admitted in Dhaka Medical College Hospital and BIRDEM Hospital over a two years period to determine the organisms responsible for nosocomial infection, their antibiotic susceptibility pattern, sources and the impact of hospital infection on patient management. Samples were collected from postoperative wounds, post catheterized urinary tract infection (UTI) and diabetic wounds. The patients without postoperative wound infection were taken as control group. To trace the sources of infection the samples from the different objects of the hospital environment were studied. The collected samples were cultured and isolated organisms were identified by colony morphology, gram staining and necessary biochemical tests. The identified organisms were tested for antibiogram pattern and plasmid profile. The predominating organisms responsible for nosocomial infection were Esch.coli (55.9%) . The other organisms were Pseudomonas sp. (33.3%), Proteus sp. (12.7%), Staphylococcus aureus (5.9%), Klebsiella sp. (4.9%) and Acinatobacter sp. (3.9%). The isolated organism showed high level of resistance to commonly used antibiotics. The resistance of the organisms markedly increased with the hospital stay. The hospital stay of the infected cases was significantly (p

Social network sites (SNS's) have connected millions of users creating the social revolution. Users' social behavior influences them to connect with others with same mentality. Social networks are constituted because of its user or organizations common interest in some social emerging issues. The popular social networking sites are Facebook, Twitter, MySpace, Orkut, LinkedIn, Google plus etc. which are actually online social networking (OSN) sites. However, the large amount of online users and their diverse and dynamic interests possess great challenges to support recommendation of friends on SNS's for each of the users. In this paper, we proposed a novel friend recommendation framework (FRF) based on the behavior of users on particular SNS's. The proposed method is consisted of the following stages: measuring the frequency of the activities done by the users and updating the dataset according to the activities, applying FP-Growth algorithm to classify the user behavior with some criteria, then apply multilayer thresholding for friend recommendation. The proposed framework shows good accuracy for social graphs used as model dataset.

Background The rhizome of Curcuma aeruginosa Roxb (Zingiberaceae) has been used as a traditional folk medicine for the treatment of rheumatic disorders in Bangladesh. The aim of the current study was the bioassay-guided isolation and purification of an antinociceptive principle from the methanol extract of C. aeruginosa rhizomes. Methods The antinociceptive activity was determined using acetic acid induced writhing and formalin induced licking in the Swiss albino mice to investigate central and peripheral antinociceptive principle of C. aeruginosa rhizomes. Vacuum Liquid Chromatography (VLC) and open column chromatography were used for separation. Crystallization was used for the purification of the isolated compound germacrone (1). Diclofenac (10 mg/kg) and aspirin (100 mg/kg) were used as positive control and 5 % carboxymethyl cellulose (CMC) in distilled water (10 ml/kg) for negative control were used in the acetic acid induced writhing and formalin induced licking methods. Results The methanol extract exhibited 37.50 and 45.31 % inhibition of writhing; 33.27 and 38.13 % inhibition of licking in the first phase and 69.72, 73.71 % inhibition of licking in the second phase at doses of 200 and 400 mg/kg, respectively. VLC of the extract yielded five fractions (Fr. 1 to Fr. 5). Fr. 1 exhibited 33.98 % inhibition that was comparably higher than other fractions (Fr. 2 to Fr. 5) at a dose of 100 mg/kg. Column chromatography of Fr. 1 generated five fractions (SF. 1 to SF. 5). Fraction SF.3 exhibited 46.88 % inhibition that was most potent among the other fractions at a dose of 50 mg/kg. Crystallization of the fraction SF.3 yielded germacrone (1), a cyclic sesquiterpene. Germacrone (1) showed 22.66, 34.77 and 51.17 % inhibition of writhing at doses of 10, 20 and 40 mg/kg, respectively; 30.43 and 37.53 % inhibition in the initial phase and 32.27 and 60.96 % inhibition in the second phase of licking at doses of 200 and 400 mg/kg, respectively. Conclusion Germacrone (1) showed a potent activity in both writhing and licking methods that indicates the compound as a central and peripheral antinociceptive principle of C. aeruginosa rhizomes with possible anti-inflammatory activity.

The mode profile of a holey index guided 2-Dimensional triangular lattice Photonic Crystal Fiber (PCF) is investigated using the effective index model of PCF. The effect of variation in air hole diameter, of a constant lattice size, on the mode profile is analyzed for getting the Fundamental Space- Filling Mode (FSM).

A method is presented for calculating the quality factors (Q's) and the effective-average gain and loss coefficients for the modes of a dielectric sphere which has a spatial perturbation of the imaginary part of the refractive index. The method is applicable to gain calculations in spherical lasers, to spatial hole burning and to stimulated Raman scattering in spheres. A time-independent perturbation method is also used to compute the Q's of the resonances. Results computed using both methods are compared with analytical results for layered spheres. The methods are used to compute the near-resonance backscattering by a sphere having an intensity-dependent (two-photon absorption) loss. >

The lasing spectra from a Rhodamine B–doped microdroplet (85% isopropanol and 15% water) with a thermochromic additive (CoCl2.6H2O) have been observed to shift progressively toward blue as the droplet temperature is gradually increased. The absorption of the thermochromic additive increases as the temperature of the solution is increased. The mechanism of temperature-dependent absorption is reviewed. We propose that the temperature-dependent shifting of the lasing spectra might be used for the determination of the droplet temperature.

The frequencies of the normal azimuthal modes of a slightly deformed droplet that is axisymmetric about its flow direction are no longer degenerate but vary with position along the droplet rim. We measured the wavelength variation along the entire rim of a dye-lasing droplet with a spectrograph and a CCD array. We determined the amplitude and the shape of the droplet deformation from the observed and predicted parabolic dependence of wavelength variation with distance along the spectrograph slit.

Background Melioidosis, caused by Burkholderia pseudomallei, is an endemic disease in Bangladesh. No systematic study has yet been done to detect the environmental source of the organism and its true extent in Bangladesh. The present study attempted to isolate B. pseudomallei in soil samples and to determine its seroprevalence in several districts in Bangladesh. Methodology and Results Soil samples were collected from rural areas of four districts of Bangladesh from where culture confirmed melioidosis cases were detected earlier. Multiple soil samples, collected from 5–7 sampling points of 3–5 sites of each district, were cultured in Ashdown selective media. Suspected colonies of B. pseudomallei were identified by biochemical and serological test, and by polymerase chain reaction (PCR) using 16s rRNA specific primers. Blood samples were collected from 940 healthy individuals of four districts to determine anti- B. pseudomallei IgG antibody levels by indirect enzyme linked immunosorbent assay (ELISA) using sonicated crude antigen. Out of 179 soil samples, B. pseudomallei was isolated from two samples of Gazipur district which is located 58 km north of capital Dhaka city. Both the isolates were phenotypically identical, arabinose negative and showed specific 550bp band in PCR. Out of 940 blood samples, anti- B. pseudomallei IgG antibody, higher than the cut-off value (>0.8), was detected in 21.5% individuals. Seropositivity rate was 22.6%-30.8% in three districts from where melioidosis cases were detected earlier, compared to 9.8% in a district where no melioidosis case was either detected or reported (p 50 years respectively. The seropositivity rates were 26.0% and 20.6% in male and female respectively, while it was 20–27% among different occupational groups. No significant association was observed with gender (χ2 = 3.441, p = 0.064) or any occupational group (χ2 = 3.835, p = 0.280). Conclusion This is the first study demonstrating the presence of B. pseudomallei in the environmental (soil) samples of Bangladesh. It also suggested that a large proportion of people, residing in these districts, were exposed to the organism., Author Summary Melioidosis, caused by B. pseudomallei, can be a fatal disease if not treated with appropriate antibiotics. The organism is mainly present in soil and water in endemic areas, and people become infected through skin inoculation, inhalation or ingestion. The disease has been sporadically detected in Bangladesh over last several decades. However, its actual prevalence in Bangladesh is largely unknown due to the lack of systematic study and awareness of the medical community about the disease and the organism. In order to address the issue, we have undertaken this study to assess the presence of the organism in the soil as well as its magnitude of exposure among the people of selected areas of the country. The study revealed the presence of B. pseudomallei in the soil and its exposure among the people of different areas. The information would increase the awareness of the medical community for prevention and correct diagnosis of the disease.

In the paper we have focused the effect of Hematocrit on flow parameters, such as resistance, frictional resistance, and skin friction due to stenosis in the artery taking blood as non-Newtonian fluid. It has been found that resistance increases with the increasing of hematocrit level and stenos is height. It is also shown that a skin-friction increase with increasing of stenosis height and decreases with the decreasing of stenosis height. Moreover the effect of stenosis shape parameter is observed on resistance and skin-friction due to different hematocrit level. Finally we compare our result graphically.

This paper explores employee motivation in one of the UK based voluntary organizations. It used a mixture of primary and secondary data. Primary data were collected in the form of questionnaires. By using Frederick Herzberg’s two factor theory we found that, in the absence of sufficient financial rewards, non-financial rewards such as: extra days off for employees; implementation of employee of the month; and simple verbal recognition in an attempt to recognise employee’s efforts were key motivating factors for the employees. Recommendations to management were made in terms of offering flexible hours and quality supervision in order to motivate unpaid volunteers.

Aims & Objectives: Ocimum sanctum L. popularly known as Tulsi is a medicinal plant that has been used for curing various diseases since ages. In the present study we used leaf extract of Ocimum sanctum for its anti-ulcer property by inducing stress ulcers on rats. Materials and Method: Albino rats were randomly allocated to different experimental groups and aqueous leaf extract of Ocimum sanctum was given for 7 days. Stress ulcers were induced by restraint and ethanol administered methods and results were compared with standard drug ranitidine. After that animal was sacrificed and stomach was dissected out and stomachs were observed for the ulceration with the help of magnifying lens and studied its external, internal surface and ulcer index was evaluated according to the severity of ulcers. The stomach were stored and fixed in 5% formalin and studied for histopathological changes. Results: The ulcer index was high in control group. Animal pretreated with Ocimum sanctum at the dose 100 & 200 mg/kg showed few signs of mucosal injury and the percentage of damage were less compared to control group. Conclusion: In the present study pretreatment with Ocimum sanctum at dose 100-200 mg/kg caused a significant anti-ulcer effect in rats in comparison with control group and its effect is comparable to the standard drug ranitidine, as evidenced by the reduction in the ulcer scores.

High-Q morphology-dependent resonances (MDR's) in microdroplets provide optical feedback for nonlinear processes such as stimulated Raman scattering (SRS). The SRS signal from weaker gain modes or from the minority species in a binary mixture droplet is small, because of depletion of the pump beam by the strongest-gain Raman mode. We present an effective- average Raman gain formula and discuss the factors that contribute to the enhancement of SRS intensity. Spatial overlap between pump wave and SRS wave is an important factor in determining the SRS intensity. We have observed that in a binary mixture microdroplet, the SRS of the majority species is more efficient (because of good spatial overlap) in pumping the minority species than the input laser itself. Laser-induced distortion can couple light efficiently into a droplet. We have used a variable number (3 - 6) of mode-locked 100-psec laser pulses focused on the droplet rim. The SRS emission from a minority species increases as the number of input pulses is increased, because cumulative laser-induced surface distortion couples more energy into the droplet. SRS signal at the Stokes shift of a weaker gain mode or of the mode of a minority species can be enhanced by seeding light at the SRS wavelengths. The seed signal is obtained from the fluorescence of a dye added to the microdroplet or from external coupling of light into the droplet. A lasing dye (Rhodamine 6G) is added to pure ethanol droplet. By using an excimer-pumped tunable dye laser as the excitation source, the weaker gain C-C-O mode (882 cm-1 Stokes shift) of ethanol is overlapped spectrally with the fluorescence and lasing of R6G. The SRS signal of the C-C-O mode is enhanced, because (1) the fluorescence of R6G at the SRS wavelength adds to the spontaneous SRS emission and (2) the gain from population inversion adds to the Raman gain. We have also observed enhanced SRS emission from a minority species (benzene) in dodecane by using internal dye seeding. We externally seeded ethanol SRS (2928 cm-1) in a binary mixture (12% ethanol and 88% water) microdroplet by using a frequency-doubled Nd-YAG pumped tunable dye laser. A large (factor of 45) enhancement in the ethanol SRS (integrated over 100 shots of a 10-ns laser) has been observed.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Optical scattering by fuel droplets of spray jets can provide information about droplet evaporation in a combustion chamber. Evaporating fuel droplets are often spatially inhomogeneous and non-spherical. Spatial inhomogeneities in droplets can occur in the imaginary or in the real part of the index of refraction. We review some of the theoretical progress to date in modeling scattering by non-spheres and by inhomogeneous droplets. These models help investigate the effects of shape and refractive index perturbations on morphology dependent resonances of droplets. These investigations may lead to the use of such effects as tools for droplet diagnostics.

Computed results for some linear optical problems relevant to nonlinear optics in droplets are presented and discussed. (1) The electric energy density distributions inside homogeneous spheres (water droplets) illuminated with plane waves are computed using Lorentz-Mie theory and geometrical optics ray tracing. (2) The electric energy densities inside spheres illuminated by Gaussian beams are computed using an angular spectrum of plane waves approach, a technique applicable to scattering of Gaussian beams by axisymmetric objects. (3) The Q's and resonance locations of spherically symmetric, radially-inhomogeneous spheres are computed numerically. (4) The Q's and resonance locations of perturbed, homogeneous, droplets are computed using the T-matrix method. (5) The Q's and resonance locations of inhomogeneous, spherically-asymmetric droplets are computed using the T-matrix method.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

With addition of an absorber to dye-doped microdroplets, an absorption-dependent blue shift in the lasing spectra has been observed. The better the spectral overlap between the absorption and the fluorescence spectra of the dye, the larger the blue shift. The experimental observations are explained by a simple model of dye lasing in an optical cavity that includes losses because of the absorber and radiation leakage.

Dispersive optical bistability in a dielectric sphere is modeled. The analysis is applicable to cases in which the incident frequency is near a morphology-dependent resonance of the sphere. The refractive index of the sphere is assumed to vary as m(r) = m0 + m2I(r), where I(r) is the internal intensity at position r. In general I(r) contains all the modes of the sphere. However, we first obtain a simplified analytical expression for bistability in which we assume that I(r) consists of a single near-resonant mode. We also analyze the bistability problem; in the analysis we include all the modes of the sphere in computing I(r). The agreement between the all-mode and the single-mode results is good when the incident frequency is within a few linewidths of ahigh-Q (>104) mode. We compare bistability in a dielectric sphere with that in a Fabry–Perot cavity. We use a quasi-steady-state approximation to calculate the time-dependent backscattering from a CS2 sphere near a resonance. The computed backscattered intensity has bistable characteristics.

The resonance locations and quality factors (Q’s) of morphology-dependent resonances in an inhomogeneous sphere with a small refractive-index perturbation are computed by using the T-matrix method for layered axisymmetric objects and a time-independent perturbation method. The resonance locations computed are similar. The changes in the Q computed with the two methods are typically within a factor of 2 or 3 of each other when the change from the unperturbed Q is less than 50%. For the type of perturbation that we consider here, an increase in the refractive index in a nonconcentric spherical region inside the larger sphere, the resonance frequencies always decrease, but the Q’s decrease or increase depending on the unperturbed Q and the location and shape of the perturbation. The change in frequency and the change in Q depend on the overlap of the perturbation with the energy-density distribution of the morphology-dependent resonance. For the same overlap, the change in Q is much larger for higher-Q modes than for lower-Q modes. A refractive index perturbation that causes a relatively small change in Q may cause the resonance frequency of a high-Q MDR to shift by many linewidths.