The sequential pathology of a genotype XIII Bangladeshi strain of Newcastle disease virus (NDV) was studied in 5-weeks old chickens. Layer chickens of ISA Brown breed were inoculated through the ...intranasal and intraocular routes with the BD-C161/2010 strain of NDV and examined at different times post-infection (pi). NDV-infected chickens showed depression at 3 days pi (dpi) followed by dropped wings, paralysis and death starting at 4 dpi. Lungs of infected chickens showed hemorrhagic lesions starting at 24 hours pi (hpi) that was followed by pallor and slight contraction by 2 to 3 dpi and subsequently developed into severe hemorrhagic pneumonia with mononuclear cell infiltration. Hemorrhagic and necrotizing lesions were found in different visceral organs including proventriculus, intestine, gut-associated lymphoid tissues, liver and kidneys starting at 3 dpi that progressed rapidly. Severe lymphoid depletion was observed in the thymus, spleen and bursa of Fabricius starting at 1–3 dpi followed by hemorrhages, necrosis, inflammation and atrophy at 4–5 dpi. In the brain, mild neuronal lesions such as focal to diffuse encephalitis with encephalomalacia was observed at 2–3 dpi and moderate and diffuse meningoencephalitis with encephalomalacia at advanced stages. In conclusion, the BD-C161/2010 strain of NDV produced lesions typical of velogenic viscerotropic pathotype of NDV.
This study aimed to salvage the study population from the fatality that occurs due to iatrogenic injury to the thoracic cavity's pleural membrane.
An experimental study of temporomandibular joint ...arthroplasty with costochondral graft was carried out on 72 healthy '
' species of male rabbits. The rabbits were distributed into two age groups: growing (3-4 months) and adult (12-18 months). All the procedures were carried out under general anesthesia with xylazine hydrochloride and ketamine hydrochloride after calculating the doses, maintained by halothane and O
inhalations. Out of 72 rabbits, 33 rabbits had accidental perforation of the pleural membrane observed that required a chest drain.
In this study, 21 (63.64%) rabbits received chest drain and salvaged. The rest of the rabbits (
= 12; 36.36%) that did not receive any chest drain and died. Most of the rabbits (
= 17; 81%) were under the growing group, weighing less than 2 kg and four (19%) were adult rabbits.
This manual chest drain is life-saving for rabbits. It is a new addition to the advancement of thoracic surgery on animals. It is cost-effective and safe. The developed customized drainage system may make it easier to harvest the costochondral graft-related experiments.
Background
Bovine spongiform encephalopathy (BSE) is an emerging zoonotic disease of cattle associated with pathological prion protein (PrPsc) transmitted via meat and bone meal (MBM). Although ...Bangladesh did not experience a BSE outbreak but the country could not export animal products to developed countries as has not yet been declared BSE free country by OIE due to lack of scientific risk evaluation for BSE. The objectives were identification of hazard, release and exposure pathways of pathological prion protein through MBM and analysis of risk for the occurrence of BSE in Bangladesh.
Methods
The scientific data were reviewed, hazards were scheduled and surveys were conducted on livestock production system, import of MBM and its use to identify the hazards present in Bangladesh context. The analysis was done by the ‘OIE Risk Analysis Framework 2006 and European Union (EU) Scientific Steering Committee (SSC) 2003’. From the historical reviews, import of MBM and its use was identified, as external hazards.
Results
The analysis revealed that these hazards had negligible or moderate risk for the introduction of infectious PrPsc as Bangladeshi cattle are vegetarian cattle. No milk replacer was used and use of slaughtered waste in the animal feed industry is absent. Unconsumable bones are processed to produce bone chips, fertilizers and bone meal for poultry feeds. Scrapie was never prevalent in Bangladesh. Therefore, risk from the internal challenge was negligible in Bangladesh for the occurrence of classical BSE. These prevented the propagation of BSE infectivity and eliminated BSE infectivity from the system very fast, if that was present.
Conclusions
It was concluded that introduction of PrPsc into cattle population of Bangladesh through MBM was very negligible. Therefore, Bangladesh can be considered as BSE negligible risk country.
Bovine Spongiform Encephalopathy (BSE) is a zoonotic disease of cattle associated with infectious prion protein (PrPsc) transmitted via meat and bone meal (MBM). Although Bangladesh did not experience a BSE outbreak but the country could not export animal products to developed countries as has not yet been declared BSE free country by OIE due to lack of scientific risk evaluation for BSE. Surveys were conducted on livestock production system, import of MBM and its use to identify the hazards present in Bangladesh context. The analysis was done by the ‘OIE Risk Analysis Framework 2006 and European Union (EU) Scientific Steering Committee (SSC) 2003’. The external and internal challenge analyses put Bangladesh as negligible risk country for the introduction of infectious PrPsc among cattle population.
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•Molecular dynamics is used to study the mechanical characterization of Gr/WSe2 vertical heterostructures.•Mechanical properties and fracture mechanisms of the Gr/WSe2 are strongly ...direction-dependent.•Fracture initiates from the graphene and WSe2 layers for armchair and zigzag loading, respectively.•The WSe2 sheet undergoes a phase transformation from h-WSe2 to t-WSe2 during zigzag loading.
Assembling layered materials in the form of vertically stacked heterostructures has emerged as a facile way to leverage the properties of each component and fabricate novel highly-tailored architectures with advanced functionalities. In this study, we employ molecular dynamics (MD) simulations to characterize the temperature-dependent tensile mechanical properties of graphene/WSe2 vertical heterostructure along both the armchair and the zigzag directions utilizing a hybrid scheme of various interatomic potentials. It is found that the tensile strength of the WSe2 monolayer can be significantly improved when supported by graphene benefiting from the synergistic effects of their individual strengths. The comparisons of the predicted tensile properties of the heterostructure with that of the mixing rule exhibit excellent conformity. We found that while the bare WSe2 is more resilient to fracture along the armchair direction, the graphene supported WSe2 layer endures larger tensile stress and strain for zigzag loading. This study further reveals fascinating chirality in mechanical properties and failure mechanism of the heterostructure. Fracture initiates from the graphene layer for armchair loading, whereas the WSe2 sheet becomes more prone to fracture under zigzag loading. Crack propagates along the zigzag direction and results in the complete tearing of the specimen for armchair loading, while the crack propagation is confined in a random small region for the zigzag loading. The WSe2 nanosheet experiences major atomic rearrangements and undergoes a phase transformation from trigonal (h-WSe2) to the distorted octahedral phase (t-WSe2) during zigzag loading. Increasing temperature is found to play a crucial role in deteriorating the mechanical properties of the heterostructure. This study offers a comprehensive characterization of the tensile properties of Gr/WSe2 vertical heterostructure and discloses important deformation mechanisms that will enable the efficient utilization of this material.
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•EMD is used to study the phonon thermal conductivity (PTC), melting characteristics, and tensile strength of both SLGeNR and BiLGeNR.•BiLGeNR exhibits significantly lower PTC than ...SLGeNR.•PTC of SLGeNR displays an inverse relation with temperature, biaxial compressive strain, and monovacancy defects.•PTC of SLGeNR has been seen to increase gradually with increasing biaxial tensile strain, length and width of the nanoribbon.•BiLGeNR demonstrates high tensile strength and melting temperature compared to SLGeNR.
Two-dimensional germanene has provided a cornucopia of new functionalities in the field of nanotechnology owing to its remarkable electronic and thermoelectric attributes. The robust spin–orbit coupling and high carrier mobility give rise to many salient features including non-trivial topological properties, quantum spin-Hall state near room temperature, and topological superconductivity, rendering it an excellent contender for valleytronics, spintronics, and quantum computation. As such, an in-depth characterization of thermal and mechanical properties of germanene is crucial for its practical implication and efficient operation, which remains elusive. Here, we employed equilibrium molecular dynamics simulations utilizing Stillinger Weber potential to reveal the mechanical strength, melting temperature, and phonon thermal conductivity (PTC) of single-layer germanene nanoribbon (SLGeNR) and bilayer germanene nanoribbon (BiLGeNR). Effects of temperature, biaxial tensile and compressive strain, monovacancy defects, length and width of the nanoribbon on the PTC have been rigorously investigated. It has been found that PTC of SLGeNR could be substantially reduced by BiLGeNR. Our simulation results suggest that PTC of SLGeNR demonstrates an inverse relation with temperature, biaxial compressive strain, and monovacancy defects while biaxial tensile strain, length and width of the nanoribbon increases the PTC of SLGeNR significantly. To understand the PTC more profoundly, phonon density of state (PDOS) profiles have been studied. The BiLGeNR demonstrates more tensile strength as well as melting temperature compared to SLGeNR. This study offers a comprehensive guideline for engineering the TC as well as discloses important mechanical and melting characteristics of the SLGeNR and BiLGeNR for a wide range of applications in flexible nano-electronics and thermoelectric nanodevices.
Poultry meat is an important source of animal protein in Bangladesh. Small-scale poultry production plays a crucial role in the socio-economic development and nutritional requirements of rural and ...peri-urban households and provides an income source for resource-poor areas. Therefore, focusing on small-scale poultry production remains important. However, improper management, disease outbreak, market volatility and many other factors are typically responsible for the sustainability of this rising prospect of small-scale poultry production potential. The recent pandemic coronavirus disease of 2019 (COVID-19) tremendously influenced the sustainability of the small-scale poultry sector. This review addressed Bangladeshi small-scale poultry production and its market value, identified issues, and suggested potential guidelines to sustain the small-scale sector
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•Molecular dynamics is used to study tensile properties and fracture mechanism of CdSe nanowire.•The effect of temperature, size, loading direction, vacancy defects, and strain rates ...are studied.•Young’s modulus and ultimate strength show inverse relationship with temperature and defects.•The 111 direction shows largest ultimate strength, Young’s modulus, and fracture toughness.•The ultimate strength is more sensitive to Cd vacancy, while the Young’s modulus is to Se vacancy.
Understanding the mechanical properties of cadmium selenium (CdSe) nanowire has received intense research interest due to its versatile application in semiconductor industries. We investigated the tensile mechanical properties and fracture mechanism of zinc-blende CdSe nanowire (NW) through molecular dynamics simulations by considering the effects of temperature variation, NW size, different loading directions, vacancy defects, and strain rates. We found that both ultimate tensile strength (UTS) and Young’s modulus (YM) linearly decrease with increasing temperature but increase with nanowire cross-sectional area. The 111 -directed CdSe NW shows the largest UTS, YM, and fracture toughness whereas, the lowest values are obtained for 100 direction. The largest failure strain is exhibited by 110 direction. The UTS is found more sensitive in the presence of Cd vacancy, while the YM is more sensitive to the removal of Se atoms. We noticed that at 100 K, the 100 -directed CdSe NW fails along {111} cleavage plane, however, at 600 K, both {111} and {100} cleavage planes activate and cause fracture at a lower strain value. Finally, both the fracture strength and strain increase with the increment in strain rates. The mechanical properties and fracture characteristics of the CdSe NW elucidated in this study will be a guide to design and fabricate CdSe-based optoelectronic and electronic devices.
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•The effect of various defects and temperature on thermal conductivity of silicene is studied using NEMD.•Only 5% of carbon doping are found to reduce the thermal conductivity of pure ...silicene by ~ 71%.•Reduction of thermal conductivity is more pronounced with the increased vacancy than carbon.•PDOS reveals the high-frequency regime exhibit a redshift for carbon-doped silicene.•Both pristine and carbon-doped silicene exhibit isotropic thermal conductivity behavior.
Silicene has recently grabbed tremendous attention in the scientific community owing to its superb electronic and thermal properties and the promise of high-efficiency thermoelectric operations. Notwithstanding rigorous analyses of its electronic properties, little attention has been paid so far to explore and tailor the thermal transport characteristics of silicene. This study employed optimized Tersoff potential to extensively investigate the thermal conductivity (TC) of pristine and defective silicene using non-equilibrium molecular dynamics (NEMD) simulations. We analyzed theinfluence of temperature variation, percentage of carbon doping, andmonovacancy concentration on the phonon TC along both armchair and zigzag directions and elucidated the underlying mechanisms that modulate these effects. The simulation results reveal excellent isotropic behavior of the material in the considered temperature regime. Our predicted room-temperature TC of pristine silicene of ~ 20 W/m.K shows excellent conformity with prior studies. Simulation results suggestthat the TC deteriorates significantly with increasing concentration of carbon doping. It is revealed that incorporating only 5% of carbon dopants can reduce the TC of silicene by ~ 71%. Meanwhile, with the increase in temperature from 100 K to 600 K, the thermal conductivities of both pristine and carbon-doped silicene are also found to decline dramatically by ~14 W/m.K and ~9 W/m.K, respectively. The vacancy defect study reveals that thermal conductivities of both pure and carbon-doped silicene are also a strong function of vacancy concentration and can be reduced by ~ 58% by removing only 1% of silicon atom from the pristine nanosheet. It is further disclosed that the impact of vacancy on regulating the TC is more pronounced in pristine silicene than the carbon-doped silicene. To obtain a detailed insight into the thermal transport mechanism, phonon density of states (PDOS) is computed using the fast Fourier transform of the atomic velocity autocorrelation function. The PDOS discloses interesting phonon spectrum features under impurity doping, temperature variation, and increased vacancy concentration. Overall, this study offers a comprehensive roadmap for engineering the thermal conductivity of silicene and will grease the wheels for designing efficient thermal management systems for the present silicon-based semiconductor industry.
We performed pathological and molecular virological investigation of three outbreaks of highly pathogenic avian influenza (HPAI) in a quail farm and two duck farms of Mymensingh and Netrokona ...districts of Bangladesh in 2011. HPAI viruses of subtype H5N1 were detected from all three outbreaks and phylogenetic analysis of HA gene sequence placed the viruses into clade 2.3.2.1. The outbreak in the quail farm was characterized by acute death with 100% mortality within two days. Marked haemorrhages and congestion with necrotic and inflammatory lesions in the respiratory tract, liver, pancreas and kidneys were the major gross and histopathological lesions. In the case of ducks, nervous signs were the remarkable clinical manifestations and the mortality was around 10%. No significant gross lesions were observed at necropsy. Non-purulent encephalitis with gliosis and neuronal degeneration was observed on histopathological examination. By immunohistochemistry, viral antigen could be detected in different organs of both quails and ducks. This study records varying clinical and pathological manifestations of HPAI in ducks and quails following natural infection with the same strain of the virus.
RESEARCH HIGHLIGHTS
HPAIV of clade 2.3.2.1 was detected from clinical outbreaks in quails and ducks
Sudden death with severe haemorrhages in various organs was found in quails
Pronounced nervous signs with non-purulent encephalitis were observed in ducks
Viral antigen could be localized in different organs by immunohistochemistry
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