AP2 transcription factors play a crucial role in plant development and reproductive growth, as we... more AP2 transcription factors play a crucial role in plant development and reproductive growth, as well as response to biotic and abiotic stress. However, the role of TaAP2-15, in the interaction between wheat and the stripe fungus, Puccinia striiformis f. sp. tritici (Pst), remains elusive. In this study, we isolated TaAP2-15 and characterized its function during the interaction. TaAP2-15 was localized in the nucleus of wheat and N. benthamiana. Silencing of TaAP2-15 by barley stripe mosaic virus (BSMV)-mediated VIGS (virus-induced gene silencing) increased the susceptibility of wheat to Pst accompanied by enhanced growth of the pathogen (number of haustoria, haustorial mother cells and hyphal length). We confirmed by quantitative real-time PCR that the transcript levels of pathogenesis-related genes (TaPR1 and TaPR2) were down-regulated, while reactive oxygen species (ROS)-scavenging genes (TaCAT3 and TaFSOD3D) were induced accompanied by reduced accumulation of H2O2. Furthermore, we ...
Rising global temperatures have been suggested to favor cyanobacteria over eukaryotic algae, but ... more Rising global temperatures have been suggested to favor cyanobacteria over eukaryotic algae, but UV‐B fluxes are also predicted to remain high and may interact with temperature to affect algal growth. To understand the interactive effects of temperature and UV‐B radiation, cultures of Microcystis aeruginosa and Anabaena circinalis were grown at either 25 or 30°C and then exposed to an acute irradiance of UV‐B (1.4 W m−2). Both species showed differences in growth rates at both temperature regimes. The growth rates of M. aeruginosa (0.41 ± 0.02 day−1) and A. circinalis (0.38 ± 0.01 day−1) were higher at 25 and 30°C, respectively. Rates of damage (k) and repair (r) were calculated from the kinetics of change in effective quantum yield, Fv'/Fm'. Analysis of the estimates of r and k shows that M. aeruginosa exhibited relatively high values for both parameters, compared to A. circinalis, at both growth temperatures. In both species, repair rates were higher at 30°C than at 25°C but in A. circinalis damage was also greater at the higher temperature. In contrast, M. aeruginosa showed a lower damage rate at the higher temperature. For both species, the ratio of r:k was higher at the higher temperature. However, the percent inhibition of effective quantum yield by UV‐B was greater in A. circinalis than in M. aeruginosa as the r:k was lower A. circinalis. Therefore, it could be concluded that temperature may influence growth and bloom formation of cyanobacteria and that different species may respond differently to UV‐B and temperature interactions.
The effects of stocking density of tilapia Oreochromis niloticus with the inclusion of silver car... more The effects of stocking density of tilapia Oreochromis niloticus with the inclusion of silver carp Hypophthalmichthys molitrix were evaluated in the C/N-CP prawn Macrobrachium rosenbergii farming system in triplicate. Management practices were same for all treatments. Bamboo side shoots were posted vertically into the pond bottoms as a periphyton substrate. A locally formulated and prepared feed containing 15.44% crude protein with a C/N ratio 15 were applied twice daily in all ponds. Maize flour was supplied in water for raising the C/N ratio 20 in all treatments. Water quality parameters, except transparency and chlorophyll a, did not differ significantly (P > 0.05) among the treatments. The periphytic abundance and biomass differed significantly (P < 0.05) among the treatments and even among different months. Although the individual harvesting weight, individual weight gain, and SGR were significantly higher (P < 0.05) in the T 10000 treatment compared to T 15000 and T 20000 treatments, respectively, the gross and net yields of tilapia were significantly higher (P < 0.05) in the treatment T 20000 followed by T 15000 and T 10000 treatments resulting in higher combined gross and net yield of both prawn and tilapia (16.05 and 16.92%, 32 and 33.59% from the later two treatments, respectively) with a higher economic return (BCR 0.53) during a 122-day culture period. As a whole, the study revealed that prawn, tilapia, and silver carp with a stocking density at 30,000,
International Journal of Computer Applications, 2016
Soil nailing is one of the good techniques for the improvement of natural and artificial slope. B... more Soil nailing is one of the good techniques for the improvement of natural and artificial slope. By the application of soil nails the stability can be increased of an unstable slope. The appropriate position of reinforcement can give the ultimate result, and it will be solution of reducing cost. In this paper, an attempt has been made to show the stability of a reinforced dry slope at different nail angles with horizontal axis, and determine the optimum nail inclination to get maximum factor of safety. The analysis was based on numerical analysis by using SLOPE/W (Geo-slope 2007). The factor of safety has been determined using the limit equilibrium (LE) method within the Morganstern-Price method along with Mohr-Coulomb expression. The results show that the factor of safety (FOS) of slope increases with the application of soil nail. The results also show that with the increase of inclination the factor of safety of the slope increases, but after reaching the maximum value further increases of inclination it decreases. The optimum angle of nail was found at 30ο with the horizontal.
Silk fibre is one of the important and demanded textile fibre in the sector of textile fabric and... more Silk fibre is one of the important and demanded textile fibre in the sector of textile fabric and garments manufacturing. In the industrial sector the coloration of silk fabric is done by acid dyes. In this paper, laboratory experiments were done for coloration of silk fabric. For coloration two different dyes, acid dye (Nylosan Orange NRL) and reactive dye (Lanasol Orange RG) have been used with their Different recipe, separately applied on different samples but with same properties of silk fabrics. Different tests like wash fastness, rubbing fastness, perspiration test, tensile strength and elongation were conducted on the dyed samples and comparison was made among all the results from Acid dyed and Reactive dyed samples. Getting better wash fastness, better absorbency and other positive test results for reactive dyes leads to the conclusion, that dyeing of silk with reactive dye has a great prospect in textile coloration.
The textile and apparel industries in Bangladesh are playing an utmost important role offering tr... more The textile and apparel industries in Bangladesh are playing an utmost important role offering tremendous opportunities for the economy of Bangladesh. But, hasty and unplanned clustered growth of industries leads to adverse environmental consequence in an alarming way. This work is aimed at giving emphasis on the present pollution scenario in Bangladesh due to textile effluent. The liquid effluents from industries are causing major havoc to the environment, ecology, agriculture, aquaculture and public health since the development of textile industries in the country. In this paper, effluent characterization results of last ten years (2005-2014) are focused. We found physicochemical parameters of Textile effluents in Bangladesh as, Temperature (25-65°C), pH (3.9-14), TDS (90.7-5980 mg/L), DO (0-7 mg/L), COD (41-2430 mg/L), BOD (10-786 mg/L), TSS (24.9-3950 mg/L) and EC (250-63750μS/cm) from 2005 to 2014. From the available data originated from the study depicts the present pollution scenario in Bangladesh with tremendous violation of laws to meet requirement of waste discharge quality standards. Now it has become a prerequisite to set up ETP in each industrial establishment, particularly at dyeing industries that were discharging huge amount of liquid waste to the rivers every day.
Research Journal of Pharmaceutical, Biological and Chemical Sciences
In this study immediate release and sustained release tablets of Vildagliptin was developed. Phar... more In this study immediate release and sustained release tablets of Vildagliptin was developed. Pharmabrust was used as super disintegrating agent in increasing order in immediate release formulations and methocel k4M CR as rate retarding polymer in sustained release formulations. Tablets were formulated by direct compression method. The in-vitro release profile were determined using USP I apparatus. The release profile of immediate release tablet of all the formulations was 95-100% within 45 minutes. The release profile of sustained release FS-1, FS-2, FS-3, FS-4, FS-5, FS-6 and FS-7 was 94%, 99%, 72%, 76%, 65% and 74% within 8 hours. Formulated tablets were evaluated for physical parameters such as average weight, thickness, disintegration time, potency, LBD, TBD, compressibility Index and angle of repose. All the physical properties of prepared tablets were within limit. Zero order, First order, Higuchi and Korsmeyer et al. models were used to estimate the kinetics of drug release. ...
Advanced materials (Deerfield Beach, Fla.), Jan 14, 2015
A high-quality mixed-organic-cation perovskite (MA)x (FA)1- x PbI3 is prepared from a phase-pure ... more A high-quality mixed-organic-cation perovskite (MA)x (FA)1- x PbI3 is prepared from a phase-pure non-stoichiometric intermediate complex (FAI)1- x -PbI2 . The phase-pure (FAI)1- x -PbI2 probably facilitates homogenous nucleation and modulates the growth kinetics during the crystallization of (MA)x (FA)1- x PbI3 . This strategy can be expected to pave the way for the development of mixed-organic-cation perovskite solar cells.
ABSTRACT Two D-π-A organic sensitizers SPSGOD3 and SPSGOD4 differing in anchoring groups (cyanoac... more ABSTRACT Two D-π-A organic sensitizers SPSGOD3 and SPSGOD4 differing in anchoring groups (cyanoacrylic acid &amp; rhodanine-3-acetic acid) but with common donor (N-(9,9-dihexyl-9H-fluoren-2-yl)-9,9-dihexyl-N-phenyl-9H-fluoren-2-amine) and π- spacer (furan) have been designed and synthesized for dye-sensitized solar cells (DSSCs). The sensitizers are fully characterized by 1H NMR, 13C NMR, MS and IR spectroscopy techniques. Photophysical, photovoltaic and electrochemical properties of these dyes were investigated. The dye with cyanoacrylic acid anchor (SPSGOD3) for test cell showed maximum IPCE of 79% at 485 nm, where as the dye with rhodanine-3-acetic acid anchor (SPSGOD4) reached maximum IPCE of 67% at 536 nm. The overall power conversion efficiency (η) of DSSCs sensitized with SPSGOD3 and SPSGOD4 were 6.21% and 3.78% respectively. The higher efficiency of SPSGOD3 is resulting from higher values of open circuit voltage (Voc) and fill factor (FF).
Highly transparent mesoporous titania photoanodes with large mesopores and crystallized framework... more Highly transparent mesoporous titania photoanodes with large mesopores and crystallized framework are synthesized by surfactant-assisted sol gel method. The conversion efficiency of DSC with rare-metal-free dye (MK-2) reaches 2.6%, though the film thickness of photoanode is of sub-micron order (around 445nm). The thinness of the photoanodes and the red-light transmission of the dye maintain the high transmittance of the dye-adsorbed photoanodes (around 80% for 700-nm light), demonstrates that obtained photoanodes are promising for electricity-generating windows.
ABSTRACT Four new organic dyes, coded as CSORG6, CSORG7, CSORG8 and CSORG9, comprising electron r... more ABSTRACT Four new organic dyes, coded as CSORG6, CSORG7, CSORG8 and CSORG9, comprising electron rich thiophene derivatives as antennas and cyanoacrylic acid as acceptor, bridged by phenothiazine or phenoxazine were designed and synthesized for dye-sensitized solar cells applications. They were fully characterized with their photophysical, electrochemical properties, density functional theory (DFT), time dependent density DFT (TDDFT) and the light-harvesting properties of the new sensitizers were evaluated with nanocrystalline TiO2-based devices. Among the four diheteroanthracene based dyes, phenoxazine (CSORG7 and CSORG9) based devices afforded the best photovoltaic performance (eta) of 6% under standard AM 1.5G solar irradiation, whereas, N719 showed (eta) 6.4% under the similar fabrication and evolution conditions.
ABSTRACT We successfully designed and synthesized Ru(II) sensitizer GS7 with a new benzimidazole ... more ABSTRACT We successfully designed and synthesized Ru(II) sensitizer GS7 with a new benzimidazole ligand as electron donating group.•This is the first report on benzimidazole based sensitizer showing high efficiency in DSSC.•GS7 exhibited high power conversion efficiency of 6.07%.•The IMVS data disclosed that the sensitizer GS7 exhibited a higher charge transport resistance compared to N749.•The agreement between theoretically computed and experimental parameters is very good.
ABSTRACT Novel metal-free and fluorescent dipyrrolopyrrole (DPP) dyes consisting of a central bis... more ABSTRACT Novel metal-free and fluorescent dipyrrolopyrrole (DPP) dyes consisting of a central bis(lactam)-bearing pendent benzyl or branched hydrocarbon groups as solubilizing fragments and two orthogonal side arms (dimethylaminopropyne and benzoate anion) have been designed and synthesized. The UV/Vis absorption spectra recorded in THF are dominated by intense low-energy π–π* absorptions centered at 488 nm or 602 nm, respectively, for the phenyl- or thiophene-based DPP dyes. The fluorescence spectra also display broad bands at 555 nm (ΦF=0.57 and τF=4.6 ns) for the phenyl- and at 624 nm (ΦF=0.31 and τF=3.5 ns) for the thiophene-based molecular structures. Under standard global AM 1.5G irradiation a maximum photon-to-electron conversion efficiency of 2.54 % was achieved with dye-sensitized solar cells based on nanocrystalline TiO2 (Jsc=7.5 mA cm−2, Voc=0.49 V, and FF=0.70) for the phenyl-based DPP dye and 1.89 % (Jsc=7.1 mA cm−2, Voc=0.41 V, and FF=0.65) for the thiophene-based DPP dye.
ABSTRACT Quinoxaline derivatives show great potential in recent organic photovoltaics, not only a... more ABSTRACT Quinoxaline derivatives show great potential in recent organic photovoltaics, not only as polymer acceptors for bulk heterojuction (BHJ) solar cells but also as molecular sensitizers for dye-sensitized solar cells (DSSCs). This work focuses on the effect of π-linkers on photovoltatic performances of D-A−π-A quinoxaline-based sensitizers used for DSSCs. The extension of π-linkers is one of the viable tactics to improve the molar absorption coefficient and red-shift the absorption peak, which is beneficial to light harvesting. With respect to IQ4, a series of quinoxaline sensitizers IQ6, IQ7, and IQ8 were synthesized on the basis of a promising building block of 2,3-diphenylquinoxaline with π-linker modification. Dye IQ8, with an additional thienyl unit near the anchor group, shows little change in absorption spectra and energy levels, while in IQ6 and IQ7, the additional thienyl group close to the donor group obviously red-shifts the absorption band and positively shifts the HOMO levels. In the series of sensitizers, their adsorption amounts on the TiO2 surface are slightly decreased by introduction of a thienyl unit near the donor part and/or the introduction of alkyl chains. Their photovoltaic performances are well evaluated by the electron collection length values (Lcol), first-principles calculations, the conduction band edge (ECB), and the fluctuation of electron density or charge recombination rate in DSSCs. Instead of the electron injection efficiency (Φinj), the low charge collection efficiency (Φcol) of IQ6, IQ7, and IQ8 results in their unsatisfactory incident photon-to-current conversion efficiency (IPCE) plateaus. Also the difference of Voc among these dyes mainly arises from the fluctuation of TiO2 electron density, which is closely related to the recombination resistance. Upon increasing the thiophene number, the electron collection lengths of IQ6, IQ7, and IQ8 based DSSCs become shorter, which dramatically decreases their photocurrent with an unbeneficial preferable photovoltaic performance. As demonstrated, it is essential to have a judicious design on π-linker modification for high-performance D-A−π-A quinoxaline-based sensitizers.
Nanostructured metal oxides are gradually being interesting for their remarkable properties and m... more Nanostructured metal oxides are gradually being interesting for their remarkable properties and mechanical fields. Many methods have been used for the preparation of nanostructured metal oxides. Here we report the synthesis of TiO 2 nanoparticles by anodization method at the same time optical and structural characterization was also conducted. Anodization is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts. Anodization was carried out using a twoelectrode configuration. The close packed titanium was attached to a copper rod to form the working electrode. The titanium rod was protected by a non-conductive epoxy in order to avoid being anodized in the electrolyte. A platinum sheet (2.0×1.5cm 2) connected to a copper wire was used as the counter-electrode. Anodization was conducted in 0.5ml HF with (50ml distilled water) and 0.5ml glycerol in (50 ml distilled water) with potentials ranging from (3-10) V for 2 hours at room temperature. Anodization changes the microscopic texture of the surface and changes the crystal structure of the metal near the surface. Ultraviolet-Visible Spectroscopy (UV-Vis) and X-Ray Diffraction (XRD) were carried out to characterize the optical and structural properties of the synthesized samples respectively. Optical absorbance study in the photon wavelength range between 300 and 600 nm reveals that strong absorbance peak is positioned around 423 nm (2.93ev) whereas visible energy band is almost transparent for the materials. Based on X-ray Diffraction, TiO 2 nanparticles grown through anodization are amorphous. Interestingly, very small nanoparticles below 5 nm, have been shown using Stokes-Einstein equation to have unusual structural disorder that can substantially modify the properties of nanoparticles.
Journal of Photochemistry and Photobiology A: Chemistry, 2004
Quasi-solid state dye-sensitized solar cells were fabricated using an oligomer having three polym... more Quasi-solid state dye-sensitized solar cells were fabricated using an oligomer having three polymerizable reactive groups. Only 7% polymer concentration in the polymer electrolyte is found enough to form a stable quasi-solid structure and a three-dimensional polymer network structure is proposed. Conductivity measurement of the polymer electrolyte in different organic solvents shows that the ionic conductivity increases with decreasing the viscosity of the solvent and a high ionic conductivity of 9 mS/cm is observed for the polymer electrolyte composition of 0.2 M DMPII, 0.5 M LiI, 0.05 M I 2 in the mixed solvent of ethylene carbonate and ␥-butyrolactone (30:70 v/v). A short circuit photocurrent density of 14.8 mA/cm 2 , an open circuit voltage of 0.78 V, a fill factor of 0.70 and an overall conversion efficiency of 8.1% under AM1.5 irradiation (100 mW/cm 2) was observed when fabricated a quasi-solid state dye-sensitized solar cells using these high conducting polymer electrolyte. The quasi-solid cells with the polymer electrolyte show higher open circuit voltage than that of the liquid cells that may be due to the suppression of the back electron transfer between the conduction band of the TiO 2 electrode and the triiodide ion in the electrolyte.
AP2 transcription factors play a crucial role in plant development and reproductive growth, as we... more AP2 transcription factors play a crucial role in plant development and reproductive growth, as well as response to biotic and abiotic stress. However, the role of TaAP2-15, in the interaction between wheat and the stripe fungus, Puccinia striiformis f. sp. tritici (Pst), remains elusive. In this study, we isolated TaAP2-15 and characterized its function during the interaction. TaAP2-15 was localized in the nucleus of wheat and N. benthamiana. Silencing of TaAP2-15 by barley stripe mosaic virus (BSMV)-mediated VIGS (virus-induced gene silencing) increased the susceptibility of wheat to Pst accompanied by enhanced growth of the pathogen (number of haustoria, haustorial mother cells and hyphal length). We confirmed by quantitative real-time PCR that the transcript levels of pathogenesis-related genes (TaPR1 and TaPR2) were down-regulated, while reactive oxygen species (ROS)-scavenging genes (TaCAT3 and TaFSOD3D) were induced accompanied by reduced accumulation of H2O2. Furthermore, we ...
Rising global temperatures have been suggested to favor cyanobacteria over eukaryotic algae, but ... more Rising global temperatures have been suggested to favor cyanobacteria over eukaryotic algae, but UV‐B fluxes are also predicted to remain high and may interact with temperature to affect algal growth. To understand the interactive effects of temperature and UV‐B radiation, cultures of Microcystis aeruginosa and Anabaena circinalis were grown at either 25 or 30°C and then exposed to an acute irradiance of UV‐B (1.4 W m−2). Both species showed differences in growth rates at both temperature regimes. The growth rates of M. aeruginosa (0.41 ± 0.02 day−1) and A. circinalis (0.38 ± 0.01 day−1) were higher at 25 and 30°C, respectively. Rates of damage (k) and repair (r) were calculated from the kinetics of change in effective quantum yield, Fv'/Fm'. Analysis of the estimates of r and k shows that M. aeruginosa exhibited relatively high values for both parameters, compared to A. circinalis, at both growth temperatures. In both species, repair rates were higher at 30°C than at 25°C but in A. circinalis damage was also greater at the higher temperature. In contrast, M. aeruginosa showed a lower damage rate at the higher temperature. For both species, the ratio of r:k was higher at the higher temperature. However, the percent inhibition of effective quantum yield by UV‐B was greater in A. circinalis than in M. aeruginosa as the r:k was lower A. circinalis. Therefore, it could be concluded that temperature may influence growth and bloom formation of cyanobacteria and that different species may respond differently to UV‐B and temperature interactions.
The effects of stocking density of tilapia Oreochromis niloticus with the inclusion of silver car... more The effects of stocking density of tilapia Oreochromis niloticus with the inclusion of silver carp Hypophthalmichthys molitrix were evaluated in the C/N-CP prawn Macrobrachium rosenbergii farming system in triplicate. Management practices were same for all treatments. Bamboo side shoots were posted vertically into the pond bottoms as a periphyton substrate. A locally formulated and prepared feed containing 15.44% crude protein with a C/N ratio 15 were applied twice daily in all ponds. Maize flour was supplied in water for raising the C/N ratio 20 in all treatments. Water quality parameters, except transparency and chlorophyll a, did not differ significantly (P > 0.05) among the treatments. The periphytic abundance and biomass differed significantly (P < 0.05) among the treatments and even among different months. Although the individual harvesting weight, individual weight gain, and SGR were significantly higher (P < 0.05) in the T 10000 treatment compared to T 15000 and T 20000 treatments, respectively, the gross and net yields of tilapia were significantly higher (P < 0.05) in the treatment T 20000 followed by T 15000 and T 10000 treatments resulting in higher combined gross and net yield of both prawn and tilapia (16.05 and 16.92%, 32 and 33.59% from the later two treatments, respectively) with a higher economic return (BCR 0.53) during a 122-day culture period. As a whole, the study revealed that prawn, tilapia, and silver carp with a stocking density at 30,000,
International Journal of Computer Applications, 2016
Soil nailing is one of the good techniques for the improvement of natural and artificial slope. B... more Soil nailing is one of the good techniques for the improvement of natural and artificial slope. By the application of soil nails the stability can be increased of an unstable slope. The appropriate position of reinforcement can give the ultimate result, and it will be solution of reducing cost. In this paper, an attempt has been made to show the stability of a reinforced dry slope at different nail angles with horizontal axis, and determine the optimum nail inclination to get maximum factor of safety. The analysis was based on numerical analysis by using SLOPE/W (Geo-slope 2007). The factor of safety has been determined using the limit equilibrium (LE) method within the Morganstern-Price method along with Mohr-Coulomb expression. The results show that the factor of safety (FOS) of slope increases with the application of soil nail. The results also show that with the increase of inclination the factor of safety of the slope increases, but after reaching the maximum value further increases of inclination it decreases. The optimum angle of nail was found at 30ο with the horizontal.
Silk fibre is one of the important and demanded textile fibre in the sector of textile fabric and... more Silk fibre is one of the important and demanded textile fibre in the sector of textile fabric and garments manufacturing. In the industrial sector the coloration of silk fabric is done by acid dyes. In this paper, laboratory experiments were done for coloration of silk fabric. For coloration two different dyes, acid dye (Nylosan Orange NRL) and reactive dye (Lanasol Orange RG) have been used with their Different recipe, separately applied on different samples but with same properties of silk fabrics. Different tests like wash fastness, rubbing fastness, perspiration test, tensile strength and elongation were conducted on the dyed samples and comparison was made among all the results from Acid dyed and Reactive dyed samples. Getting better wash fastness, better absorbency and other positive test results for reactive dyes leads to the conclusion, that dyeing of silk with reactive dye has a great prospect in textile coloration.
The textile and apparel industries in Bangladesh are playing an utmost important role offering tr... more The textile and apparel industries in Bangladesh are playing an utmost important role offering tremendous opportunities for the economy of Bangladesh. But, hasty and unplanned clustered growth of industries leads to adverse environmental consequence in an alarming way. This work is aimed at giving emphasis on the present pollution scenario in Bangladesh due to textile effluent. The liquid effluents from industries are causing major havoc to the environment, ecology, agriculture, aquaculture and public health since the development of textile industries in the country. In this paper, effluent characterization results of last ten years (2005-2014) are focused. We found physicochemical parameters of Textile effluents in Bangladesh as, Temperature (25-65°C), pH (3.9-14), TDS (90.7-5980 mg/L), DO (0-7 mg/L), COD (41-2430 mg/L), BOD (10-786 mg/L), TSS (24.9-3950 mg/L) and EC (250-63750μS/cm) from 2005 to 2014. From the available data originated from the study depicts the present pollution scenario in Bangladesh with tremendous violation of laws to meet requirement of waste discharge quality standards. Now it has become a prerequisite to set up ETP in each industrial establishment, particularly at dyeing industries that were discharging huge amount of liquid waste to the rivers every day.
Research Journal of Pharmaceutical, Biological and Chemical Sciences
In this study immediate release and sustained release tablets of Vildagliptin was developed. Phar... more In this study immediate release and sustained release tablets of Vildagliptin was developed. Pharmabrust was used as super disintegrating agent in increasing order in immediate release formulations and methocel k4M CR as rate retarding polymer in sustained release formulations. Tablets were formulated by direct compression method. The in-vitro release profile were determined using USP I apparatus. The release profile of immediate release tablet of all the formulations was 95-100% within 45 minutes. The release profile of sustained release FS-1, FS-2, FS-3, FS-4, FS-5, FS-6 and FS-7 was 94%, 99%, 72%, 76%, 65% and 74% within 8 hours. Formulated tablets were evaluated for physical parameters such as average weight, thickness, disintegration time, potency, LBD, TBD, compressibility Index and angle of repose. All the physical properties of prepared tablets were within limit. Zero order, First order, Higuchi and Korsmeyer et al. models were used to estimate the kinetics of drug release. ...
Advanced materials (Deerfield Beach, Fla.), Jan 14, 2015
A high-quality mixed-organic-cation perovskite (MA)x (FA)1- x PbI3 is prepared from a phase-pure ... more A high-quality mixed-organic-cation perovskite (MA)x (FA)1- x PbI3 is prepared from a phase-pure non-stoichiometric intermediate complex (FAI)1- x -PbI2 . The phase-pure (FAI)1- x -PbI2 probably facilitates homogenous nucleation and modulates the growth kinetics during the crystallization of (MA)x (FA)1- x PbI3 . This strategy can be expected to pave the way for the development of mixed-organic-cation perovskite solar cells.
ABSTRACT Two D-π-A organic sensitizers SPSGOD3 and SPSGOD4 differing in anchoring groups (cyanoac... more ABSTRACT Two D-π-A organic sensitizers SPSGOD3 and SPSGOD4 differing in anchoring groups (cyanoacrylic acid &amp; rhodanine-3-acetic acid) but with common donor (N-(9,9-dihexyl-9H-fluoren-2-yl)-9,9-dihexyl-N-phenyl-9H-fluoren-2-amine) and π- spacer (furan) have been designed and synthesized for dye-sensitized solar cells (DSSCs). The sensitizers are fully characterized by 1H NMR, 13C NMR, MS and IR spectroscopy techniques. Photophysical, photovoltaic and electrochemical properties of these dyes were investigated. The dye with cyanoacrylic acid anchor (SPSGOD3) for test cell showed maximum IPCE of 79% at 485 nm, where as the dye with rhodanine-3-acetic acid anchor (SPSGOD4) reached maximum IPCE of 67% at 536 nm. The overall power conversion efficiency (η) of DSSCs sensitized with SPSGOD3 and SPSGOD4 were 6.21% and 3.78% respectively. The higher efficiency of SPSGOD3 is resulting from higher values of open circuit voltage (Voc) and fill factor (FF).
Highly transparent mesoporous titania photoanodes with large mesopores and crystallized framework... more Highly transparent mesoporous titania photoanodes with large mesopores and crystallized framework are synthesized by surfactant-assisted sol gel method. The conversion efficiency of DSC with rare-metal-free dye (MK-2) reaches 2.6%, though the film thickness of photoanode is of sub-micron order (around 445nm). The thinness of the photoanodes and the red-light transmission of the dye maintain the high transmittance of the dye-adsorbed photoanodes (around 80% for 700-nm light), demonstrates that obtained photoanodes are promising for electricity-generating windows.
ABSTRACT Four new organic dyes, coded as CSORG6, CSORG7, CSORG8 and CSORG9, comprising electron r... more ABSTRACT Four new organic dyes, coded as CSORG6, CSORG7, CSORG8 and CSORG9, comprising electron rich thiophene derivatives as antennas and cyanoacrylic acid as acceptor, bridged by phenothiazine or phenoxazine were designed and synthesized for dye-sensitized solar cells applications. They were fully characterized with their photophysical, electrochemical properties, density functional theory (DFT), time dependent density DFT (TDDFT) and the light-harvesting properties of the new sensitizers were evaluated with nanocrystalline TiO2-based devices. Among the four diheteroanthracene based dyes, phenoxazine (CSORG7 and CSORG9) based devices afforded the best photovoltaic performance (eta) of 6% under standard AM 1.5G solar irradiation, whereas, N719 showed (eta) 6.4% under the similar fabrication and evolution conditions.
ABSTRACT We successfully designed and synthesized Ru(II) sensitizer GS7 with a new benzimidazole ... more ABSTRACT We successfully designed and synthesized Ru(II) sensitizer GS7 with a new benzimidazole ligand as electron donating group.•This is the first report on benzimidazole based sensitizer showing high efficiency in DSSC.•GS7 exhibited high power conversion efficiency of 6.07%.•The IMVS data disclosed that the sensitizer GS7 exhibited a higher charge transport resistance compared to N749.•The agreement between theoretically computed and experimental parameters is very good.
ABSTRACT Novel metal-free and fluorescent dipyrrolopyrrole (DPP) dyes consisting of a central bis... more ABSTRACT Novel metal-free and fluorescent dipyrrolopyrrole (DPP) dyes consisting of a central bis(lactam)-bearing pendent benzyl or branched hydrocarbon groups as solubilizing fragments and two orthogonal side arms (dimethylaminopropyne and benzoate anion) have been designed and synthesized. The UV/Vis absorption spectra recorded in THF are dominated by intense low-energy π–π* absorptions centered at 488 nm or 602 nm, respectively, for the phenyl- or thiophene-based DPP dyes. The fluorescence spectra also display broad bands at 555 nm (ΦF=0.57 and τF=4.6 ns) for the phenyl- and at 624 nm (ΦF=0.31 and τF=3.5 ns) for the thiophene-based molecular structures. Under standard global AM 1.5G irradiation a maximum photon-to-electron conversion efficiency of 2.54 % was achieved with dye-sensitized solar cells based on nanocrystalline TiO2 (Jsc=7.5 mA cm−2, Voc=0.49 V, and FF=0.70) for the phenyl-based DPP dye and 1.89 % (Jsc=7.1 mA cm−2, Voc=0.41 V, and FF=0.65) for the thiophene-based DPP dye.
ABSTRACT Quinoxaline derivatives show great potential in recent organic photovoltaics, not only a... more ABSTRACT Quinoxaline derivatives show great potential in recent organic photovoltaics, not only as polymer acceptors for bulk heterojuction (BHJ) solar cells but also as molecular sensitizers for dye-sensitized solar cells (DSSCs). This work focuses on the effect of π-linkers on photovoltatic performances of D-A−π-A quinoxaline-based sensitizers used for DSSCs. The extension of π-linkers is one of the viable tactics to improve the molar absorption coefficient and red-shift the absorption peak, which is beneficial to light harvesting. With respect to IQ4, a series of quinoxaline sensitizers IQ6, IQ7, and IQ8 were synthesized on the basis of a promising building block of 2,3-diphenylquinoxaline with π-linker modification. Dye IQ8, with an additional thienyl unit near the anchor group, shows little change in absorption spectra and energy levels, while in IQ6 and IQ7, the additional thienyl group close to the donor group obviously red-shifts the absorption band and positively shifts the HOMO levels. In the series of sensitizers, their adsorption amounts on the TiO2 surface are slightly decreased by introduction of a thienyl unit near the donor part and/or the introduction of alkyl chains. Their photovoltaic performances are well evaluated by the electron collection length values (Lcol), first-principles calculations, the conduction band edge (ECB), and the fluctuation of electron density or charge recombination rate in DSSCs. Instead of the electron injection efficiency (Φinj), the low charge collection efficiency (Φcol) of IQ6, IQ7, and IQ8 results in their unsatisfactory incident photon-to-current conversion efficiency (IPCE) plateaus. Also the difference of Voc among these dyes mainly arises from the fluctuation of TiO2 electron density, which is closely related to the recombination resistance. Upon increasing the thiophene number, the electron collection lengths of IQ6, IQ7, and IQ8 based DSSCs become shorter, which dramatically decreases their photocurrent with an unbeneficial preferable photovoltaic performance. As demonstrated, it is essential to have a judicious design on π-linker modification for high-performance D-A−π-A quinoxaline-based sensitizers.
Nanostructured metal oxides are gradually being interesting for their remarkable properties and m... more Nanostructured metal oxides are gradually being interesting for their remarkable properties and mechanical fields. Many methods have been used for the preparation of nanostructured metal oxides. Here we report the synthesis of TiO 2 nanoparticles by anodization method at the same time optical and structural characterization was also conducted. Anodization is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts. Anodization was carried out using a twoelectrode configuration. The close packed titanium was attached to a copper rod to form the working electrode. The titanium rod was protected by a non-conductive epoxy in order to avoid being anodized in the electrolyte. A platinum sheet (2.0×1.5cm 2) connected to a copper wire was used as the counter-electrode. Anodization was conducted in 0.5ml HF with (50ml distilled water) and 0.5ml glycerol in (50 ml distilled water) with potentials ranging from (3-10) V for 2 hours at room temperature. Anodization changes the microscopic texture of the surface and changes the crystal structure of the metal near the surface. Ultraviolet-Visible Spectroscopy (UV-Vis) and X-Ray Diffraction (XRD) were carried out to characterize the optical and structural properties of the synthesized samples respectively. Optical absorbance study in the photon wavelength range between 300 and 600 nm reveals that strong absorbance peak is positioned around 423 nm (2.93ev) whereas visible energy band is almost transparent for the materials. Based on X-ray Diffraction, TiO 2 nanparticles grown through anodization are amorphous. Interestingly, very small nanoparticles below 5 nm, have been shown using Stokes-Einstein equation to have unusual structural disorder that can substantially modify the properties of nanoparticles.
Journal of Photochemistry and Photobiology A: Chemistry, 2004
Quasi-solid state dye-sensitized solar cells were fabricated using an oligomer having three polym... more Quasi-solid state dye-sensitized solar cells were fabricated using an oligomer having three polymerizable reactive groups. Only 7% polymer concentration in the polymer electrolyte is found enough to form a stable quasi-solid structure and a three-dimensional polymer network structure is proposed. Conductivity measurement of the polymer electrolyte in different organic solvents shows that the ionic conductivity increases with decreasing the viscosity of the solvent and a high ionic conductivity of 9 mS/cm is observed for the polymer electrolyte composition of 0.2 M DMPII, 0.5 M LiI, 0.05 M I 2 in the mixed solvent of ethylene carbonate and ␥-butyrolactone (30:70 v/v). A short circuit photocurrent density of 14.8 mA/cm 2 , an open circuit voltage of 0.78 V, a fill factor of 0.70 and an overall conversion efficiency of 8.1% under AM1.5 irradiation (100 mW/cm 2) was observed when fabricated a quasi-solid state dye-sensitized solar cells using these high conducting polymer electrolyte. The quasi-solid cells with the polymer electrolyte show higher open circuit voltage than that of the liquid cells that may be due to the suppression of the back electron transfer between the conduction band of the TiO 2 electrode and the triiodide ion in the electrolyte.
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Papers by Ashraful Islam