Search

Plant virus diseases are significant constraints in agricultural production in Bangladesh. The hot and humid environmental conditions are highly favourable for the perpetuation of the viruses as well as vectors round the year. Although, the virus diseases are recorded in many crops, vegetables and pulses are most seriously affected. Several viruses belonging to the genera Begomovirus, Cucumovirus, Potyvirus and Tospovirus have been recorded during the last decade. Whitefly and thrips-transmitted viruses have emerged as major constraints in the horticultural crops. Management of viral diseases largely depends on the control of insect vectors by widespread application of insecticides. The epidemics of leaf curl, yellow vein, yellow mosaic and bud necrosis diseases were witnessed in the recent past. However, the knowledge of identity and diversity of viruses occurring in Bangladesh are largely lacking. This review provides the first comprehensive account of viral disease problems in the cultivation of several important crops and their management in Bangladesh.

Monodisperse aerosols are essential in many applications, such as filter testing, aerosol instrument calibration, and experiments for validating models. This paper describes the design principle, construction, and performance of a monodisperse-aerosol generation system that comprises an atomizer, virtual impactor, microcontroller-based isokinetic probe, wind tunnel, and velocity measurement device. The size distribution of the produced monodisperse aerosols was determined by an optical particle counter. The effects of atomizer characteristics, the rates of minor and major flow, and solution criteria were investigated. It was found that all these parameters affect the generation of monodisperse aerosol. Finally, the expected geometric standard deviation (≤1.25) of monodisperse aerosol particles was obtained with the most suitable atomizer for 10% oleic acid in ethyl alcohol solution with 5%–15% minor flow, where the ratio between the nozzle-to-probe distance and acceleration-nozzle-exit diameter was 0.66. The constructed monodisperse-aerosol-generation system can be used for instrumental calibration and aerosol research.

Sperm sexing through flow-sorting technology is relatively expensive, requires considerable technical support and is actually not practicable in many developing countries. The aim of this study was to investigate the feasibility of producing enriched pools of X or Y chromosome-bearing sperm by a modified swim-up method. For this purpose semen was collected from five mature Nili-Ravi buffalo bulls for a period of six weeks. The qualifying ejaculates were divided into two aliquots for further processing through modified swim-up or control (untreated). After processing, semen was cryopreserved in tris citric acid extender using standard techniques. Semen quality was assessed at pre dilution, post dilution and post thawing. Validation of technique was done by using SYBR® green real time PCR using two sets of primers, PLP and SRY for X and Y chromosome of buffalo genes, respectively. Sperm recovery rates, pre freeze and post thaw sperm quality were found significantly higher in X chromosome bearing sperm fraction than Y chromosome bearing fraction and control. Mean fold relative expression of X bearing sperm was significantly higher (4-5 fold) in X chromosome bearing fraction of supernatant than Y chromosome bearing fraction (0.06 fold), similarly mean fold relative expression of Y chromosome bearing sperm was significantly higher in Y chromosome bearing fraction (4 fold) of supernatant than X chromosome bearing fraction (0.15 fold) compared to control (1.00). In conclusion, a modified swim up method proved to be an effective method for Nili-Ravi buffalo sperm sexing as validated by real time PCR.

The population of red jungle fowl is declining and needs special attention for its conservation with suitable approaches. For ex situ in vitro conservation of Indian red jungle fowl, establishment of semen cryobank is an appropriate option, for which an extender with adequate retrieval capacity for functional spermatozoa is required. Therefore, studies were designed to evaluate a wide range of extenders for cryopreservation of Indian red jungle fowl (Gallus gallus murghi) sperm to achieve maximal post-thawed semen quality and fertility. For this purpose, semen from eight mature cocks were collected, initially evaluated (percent sperm motility, volume and concentration), pooled, assessed for motility, plasma membrane integrity, viability and acrosome integrity, and divided into six aliquots for dilution (1:5; 37 °C) in Beltsville poultry, red fowl extender, Lake, EK, Tselutin poultry and chicken semen extenders. Diluted semen was cooled from 37 °C to 4 °C @ −0.275 °C/min. Glycerol (20%) was added to chilled semen, equilibrated for 10 min, filled in 0.5 mL French straws, kept over LN2 vapours for 10 min and plunged into LN2 and stored at −196 °C. Percentages of motility, plasma membrane integrity, viability and acrosome integrity were higher (P < 0.05) in red fowl extender at 0, 2 and 4 h of incubation post-thaw. After cryopreservation and post-thawing at 37 °C the highest (P < 0.05) recovery rates and absolute livability index was also recorded in red fowl extender that was thus used for further artificial insemination of cooled-diluted (Liquid) and cryopreserved sperm. The no. of fertilized eggs (Liquid, 20.6 ± 0.4; Cryopreserved, 12.6 ± 0.5), percent fertility (86.7 ± 2.2; 57.2 ± 3.9), no. of hatched chicks (18.2 ± 0.8; 10.0 ± 0.3), percent hatch (76.5 ± 2.7; 45.3 ± 2.2) and hatchability of fertilized eggs (88.3 ± 3.4; 79.6 ± 3.4) were higher with sperm respectively freshly cooled-diluted or cryopreserved in red fowl extender. However, the rates obtained with frozen-thawed sperm were already successful for cryo-banking purpose and artificial insemination practice. In conclusion, we show the first fertility success obtained with cryopreserved Indian jungle fowl sperm. In addition, the red fowl extender is superior in maintaining the quality of Indian red jungle fowl cryopreserved sperm compared to Beltsville poultry, Lake, EK, Tselutin poultry and chicken semen extender.

Overwintering larvae of the beetle Dendroides canadensis produce potent antifreeze proteins to inhibit inoculative freezing and promote supercooling. We hypothesized that addition of Dendroides canadensis recombinant antifreeze proteins (DAFPs) in the extender will improve the quality and fertility of cryopreserved Nili-Ravi buffalo (Bubalus bubalis) sperm. The study was divided into two parts: (1) Evaluation of the effect of DAFPs on the quality of frozen-thawed buffalo bull sperm and (2) Examination of the fertilizing ability of frozen-thawed buffalo bull sperm. Semen was collected from three bulls using an artificial vagina (42 °C). Qualifying ejaculates from each bull were divided into four aliquots and diluted (at 37 °C, 50 × 10(6) sperm/mL) in tris-citric acid extender containing DAFP (at 0.1, 1.0, and 10 μg/mL), and the sperm were evaluated for important characteristics relative to a control without DAFP. D canadensis recombinant antifreeze proteins at any of the three concentrations did not affect sperm progressive motility or plasma membrane integrity (PMI), either before or after the semen was cooled to 4 °C in 2 hours. However, after 24 hours of cryostorage at -196 °C, followed by thawing at 37 °C for 30 seconds, sperm progressive motility and PMI were higher (P 0.05) in extender containing DAFP at 10 μg/mL compared with control. The in vitro-fertilizing ability of cryopreserved (-196 °C) sperm supplemented with DAFP (10 μg/mL) was slightly higher (P = 0.098) compared with control, as assessed through in vitro cleavage rate of in vitro matured buffalo oocytes. Also, the in vivo fertility rate was evaluated by inseminating 100 buffaloes (50 inseminations per extender) 12 hours after standing heat. The fertility rate of cryopreserved buffalo bull sperm in terms of positive pregnancy at 90 days after insemination was clinically higher but remained statistically nonsignificant in extender containing DAFP at 10 μg/mL (52.0%) compared with control (43.8%). In conclusion, supplementation of 10 μg/mL of DAFP in the extender improved the motility and PMI of Nili-Ravi buffalo sperm after freeze-thawing, and yielded numerically higher, although statistically nonsignificant, in vitro cleavage, and in vivo fertility rate.

Lower fertility in buffaloes with frozen-thawed semen is attributed to sperm damage that is believed to be due to formation of ice crystals during freeze/thaw process. It was hypothesized that antifreeze proteins in the extender may improve the post thaw quality of buffalo bull sperm. For this purpose, two separate experiments were conducted to evaluate antifreeze proteins III (AFP III) at 0 (control), 0.1, 1 and 10 μg/mL (Experiment I) and 0 (control), 0.01, 0.1 and 1 μg/mL (Experiment II) for its effect on post thaw quality of buffalo bull semen. Semen was collected from three Nili-Ravi buffalo (Bubalus bubalis) bulls with artificial vagina (42 °C) for three weeks (replicate) per experiment. For each experiment, qualifying ejaculates (6 ejaculates/bull) were divided into four aliquots and diluted (at 37 °C having 50 × 10(6) sperm/mL) in tris-citric acid extender containing above mentioned concentrations of AFP III. Diluted semen was cooled to 4 °C in 2 h, equilibrated for 4 h, filled in 0.5 mL straws, kept over liquid nitrogen vapors for 10 min and plunged in the liquid nitrogen. After 24 h of storage, semen straws were thawed at 37 °C for 30 s to assess sperm progressive motility (SM), plasma membrane integrity (PMI), viability (live sperm with intact acrosome) and normal epical ridge (NAR). In experiment I, improvement (P0.05) in percentage SM and sperm PMI was recorded in extender containing 0.1 μg/mL AFP III compared to control, the higher concentrations (1 μg/mL and 10 μg/mL) being inefficient. While evaluating the lower concentration (experiment II), 0.01 μg/mL of AFP III in the extender it was found to be ineffective to improve semen quality parameters, while 0.1 μg/mL AFP III in extender was found better in terms of progressive motility and plasma membrane integrity of buffalo bull semen compared to control. Sperm viability and NAR remained similar (P0.05) in extenders containing different concentrations of AFP III and control in both of experiments. In conclusion addition of AFP III in the extender at 0.1 μg/mL improved the progressive motility and plasma membrane integrity of cryopreserved buffalo bull semen.

The current study investigates the suitability for using waste transformer oil (WTO) as an alternative fuel for compression ignition (CI) engine. For this purpose different properties of the WTO were determined. The different properties include density, kinematic viscosity, cetane number, calorific value, flash and fire points, fourier transform infra-red (FTIR). The investigation includes two parts. In the first part of the investigation, different properties and engine performance were conducted. In the latter part of the investigation WTO was refined by well know transesterification process and again different fuel properties and engine performance were conducted. In the text, the refined waste transformer oil is designated as RWTO. All fuel properties with WTO and RWTO were compared with those of conventional diesel fuel (DF). All properties were close to those of DF. FTIR results revealed that the WTO is a diesel like hydrocarbon. The engine performance with WTO and RWTO was much better than that of DF. Based on the findings, WTO and RWTO are suggested to be alternative fuels for CI engine.

This paper presents production of biodiesel (BD) from non-edible renewable karanja (Pongamia Pinnata) oil, determination of BD properties and influence of BD on engine performance and emissions. Bangladesh imports 2.4 million metric ton (MT) DF each year [M.N. Nabi, M.S. Akhter, K.M.F. Islam, Prospect of biodiesel production from jatropha curcas, a promising non edible oil seed in Bangladesh. International Conference on Mechanical Engineering (ICME, Dhaka, Bangladesh) Proceedings 2007, paper no. ICME07-TH-06. [1]]. It has 0.32 million hectare of unused land [M.N. Nabi, S.M.N. Hoque, M.S. Uddin, Prospect of Jatropha curcas and pithraj cultivation in Bangladesh. Journal of Engineering and Technology. IUT Dhaka, Bangladesh, 7 (1) (2009) 41-54.[2]]. It has been found that cultivating of karanja plant in such unused land; Bangladesh can reduce DF import by 28%. Karanja methyl ester (KME), which is termed as BD, has been produced by well-known transesterification process. The properties of B100 (B100) and its blends were determined mainly according to ASTM standard and some of them were as per EN14214 standard. The Fourier transform infrared (FTIR) analysis showed that the DF fuel contained mainly alkanes and alkens, while the B100 contained mainly esters. The gas chromatography (GC) of B100 revealed that a maximum of 97% methyl ester was produced from karanja oil. Engine experiment result showed that all BD blends reduced engine emissions including carbon monoxide (CO), smoke and engine noise, but increased oxides of nitrogen (NOx). Compared to DR B100 reduced CO. and smoke emissions by 50 and 43%, while a 15% increase in NOx emission was observed with the B100. Compared to DF, engine noise with B100 was reduced by 2.5 dB. (C) 2009 Elsevier B.V. All rights reserved.

The use of biodiesel is rapidly expanding around the world, making it imperative to fully understand the impacts of biodiesel on the diesel engine combustion process and pollutant formation. Biodiesel is known as the mono-alkyl-esters of long chain fatty acids derived from renewable feedstocks, such as, vegetable oils or animal fats, for use in compression ignition engines. Different parameters for the optimization of biodiesel production were investigated in the first phase of this study, while in the next phase of the study performance test of a diesel engine with neat diesel fuel and biodiesel mixtures were carried out. Biodiesel was made by the well known transesterification process. Cottonseed oil (CSO) was selected for biodiesel production. Cottonseed is non-edible oil, thus food versus fuel conflict will not arise if this is used for biodiesel production. The transesterification results showed that with the variation of catalyst, methanol or ethanol, variation of biodiesel production was realized. However, the optimum conditions for biodiesel production are suggested in this paper. A maximum of 77% biodiesel was produced with 20% methanol in presence of 0.5% sodium hydroxide. The engine experimental results showed that exhaust emissions including carbon monoxide (CO) particulate matter (PM) and smoke emissions were reduced for all biodiesel mixtures. However, a slight increase in oxides of nitrogen (NOx) emission was experienced for biodiesel mixtures.

Recent studies suggest that Epstein-Barr virus (EBV) may act as a helper virus for the development of hepatocellular carcinoma by promoting replication of the hepatitis C virus (HCV) in the infected liver. Detection of EBV DNA in a high percentage of HCV-positive human hepatocellular carcinomas (HCC) from Japanese patients has supported this concept. In order to determine whether EBV infection is associated with HCC, we examined paraffin-embedded tissues from 31 cases of non-cirrhotic livers with hepatocellular carcinoma for the presence of EBV, HCV and hepatitis B virus (HBV) infection. RNA prepared from tumor samples were used as a template for reverse transcription followed by double-nested PCR with primers for the 5' untranslated region (NT) of HCV. DNA extracts of tumor samples were tested by single polymerase chain reaction for the detection of EBV and HBV (X- and/or S-gene) DNA sequences. To control for nucleic acid integrity, all tumor samples were amplified for human beta-globin DNA by polymerase chain reaction and subjected to Southern blot hybridization. None of the cases was found to be positive for EBV. Ten HCC cases (32%) tested positive for HCV and 12 HCC cases (38%) tested positive for HBV. Six of the surveyed patients had nucleic acids of both HCV and HBV in their tumor tissue. All HCC tumor samples were positive for beta-globin. Our study shows that HCV and HBV infections, but not EBV infection, are associated with hepatocarcinogenesis in non-cirrhotic livers. Other unknown risk factors seem to be in effect in the development of hepatocellular carcinoma in non-cirrhotic livers.

During a study on ‘Refuse Recycling Processes’ in Karachi sponsored by the United Nations Centre for Human Settlements (UNCHS - Habitat), it was observed that a significant amount of Solid Food Waste, such as left overs of unleavened and leavened breads, rolls, buns, etc., is generated from restaurants, households and fast food stalls. The Solid Food Waste contained 96·3–98% organic matter, 2–3·7% ash, 4·3–9·1% fat, 5·3–14·3% protein, 50·6–80·3% carbohydrate and 309–423 cal/100 g. Biological evaluation showed that diets prepared from this Solid Food Waste were acceptable, fully consumed and well tolerated by albino rats. It has comparable nutritive potential to bread and wheat flour.