Showing papers by "Muhammad Irfan published in 2011"
TL;DR: In this review article recent developments in continuous flow heterogeneous catalytic hydrogenation reactions using molecular hydrogen are summarized.
Abstract: Microreactor technology and continuous flow processing in general are key features in making organic synthesis both more economical and environmentally friendly. Heterogeneous catalytic hydrogenation reactions under continuous flow conditions offer significant benefits compared to batch processes which are related to the unique gas-liquid-solid triphasic reaction conditions present in these transformations. In this review article recent developments in continuous flow heterogeneous catalytic hydrogenation reactions using molecular hydrogen are summarized. Available flow hydrogenation techniques, reactors, commonly used catalysts and examples of synthetic applications with an emphasis on laboratory-scale flow hydrogenation reactions are presented.
312 citations
TL;DR: The purified cellulase was compatible with four local detergent brands with up to 20 days of shelf life at room temperature suggesting its potential as a detergent additive for improved washing therefore, it is concluded that it may be potentially useful for industrial purposes especially for detergent and laundry industry.
Abstract: This paper reports the purification and characterization of kinetic parameters of cellulase produced from Trichoderma viride under still culture solid state fermentation technique using cheap and an easily available agricultural waste material, wheat straw as growth supported substrate. Trichoderma viride was cultured in fermentation medium of wheat straw under some previously optimized growth conditions and maximum activity of 398±2.43U/mL obtained after stipulated fermentation time period. Cellulase was purified 2.33 fold with specific activity of 105U/mg in comparison to crude enzyme extract using ammonium sulfate precipitation, dialysis and Sephadex-G-100 column chromatography. The enzyme was shown to have a relative low molecular weight of 58kDa by sodium dodecyl sulphate poly-acrylamide gel electrophoresis. The purified enzyme displayed 6.5 and 55oC as an optimum pH and temperature respectively. Using carboxymethyl cellulose as substrate, the enzyme showed maximum activity (Vmax) of 148U/mL with its corresponding KM value of 68uM. Among activators/inhibitors SDS, EDTA, and Hg2+ showed inhibitory effect on purified cellulase whereas, the enzyme activated by Co2+ and Mn2+ at a concentration of 1mM. The purified cellulase was compatible with four local detergent brands with up to 20 days of shelf life at room temperature suggesting its potential as a detergent additive for improved washing therefore, it is concluded that it may be potentially useful for industrial purposes especially for detergent and laundry industry.
128 citations
TL;DR: This technique allows safe and scalable ozonolysis reactions to be performed on a laboratory scale and is able to perform both the oz onolysis and quenching steps in flow mode.
105 citations
12 Dec 2011
TL;DR: The first gridless networking field trial with flexible spectrum switching nodes over 620 km field fibre links achieves successful transport, spectrum switching and defragmentation achieved for mixed line signals including 555G and coherent 100G.
Abstract: We report the first gridless networking field trial with flexible spectrum switching nodes over 620 km field fibre links. Successful transport, spectrum switching and defragmentation achieved for mixed line signals including 555G and coherent 100G.
76 citations
TL;DR: Data recorded up to two generations revealed that overexpression of Arabidopsis thaliana PHYB gene in transgenic cotton plants resulted in an increase in the production of cotton by improving the cotton plant growth, with 35% more yield.
Abstract: The phytochrome B (PHYB) gene of Arabidopsis thaliana was introduced into cotton through Agrobacterium tumefaciens. Integration and expression of PHYB gene in cotton plants were confirmed by molecular evidence. Messenger RNA (mRNA) expression in one of the transgenic lines, QCC11, was much higher than those of control and other transgenic lines. Transgenic cotton plants showed more than a two-fold increase in photosynthetic rate and more than a four-fold increase in transpiration rate and stomatal conductance. The increase in photosynthetic rate led to a 46% increase in relative growth rate and an 18% increase in net assimilation rate. Data recorded up to two generations, both in the greenhouse and in the field, revealed that overexpression of Arabidopsis thaliana PHYB gene in transgenic cotton plants resulted in an increase in the production of cotton by improving the cotton plant growth, with 35% more yield. Moreover, the presence of the Arabidopsis thaliana PHYB gene caused pleiotropic effects like semi-dwarfism, decrease in apical dominance, and increase in boll size.
56 citations
01 Jan 2011
TL;DR: In this paper, the authors dealt with the delignification of wheat straw and sugarcane bagasse with different pretreatment techniques followed by saccharification with commercial and indigenously produced cellulase enzymes.
Abstract: The present work deals with the delignification of wheat straw and sugarcane bagasse with different pretreatment techniques followed by saccharification with commercial and indigenously produced cellulase enzymes. 100 g of sugar cane bagasse and whaet straw were treated with various concentrations of H 2 O 2 (1-5% v/v) and its combination with 2% NaOH for one hour under steam at 30 psi. Sugarcane bagasse was 88% delignified with 5% H 2 O 2 + 2% NaOH whereas wheat straw showed 51% delignification with 3% H 2 O 2 + 2% NaOH. Moreover the saccharification with commercial cellulase enzyme was found to be 33.6% and 63.3% with pretreated wheat straw and sugarcane bagasse, respectively. However, very low levels of saccharification (6-14%) were found with indigenously produced cellulase enzyme.
47 citations
Journal Article•
TL;DR: Histopathologically, extensive lung edema, emphysema, thickened alveolar septa, congestion, and edema fluid in bronchioles were observed.
Abstract: In an outbreak of hemorrhagic septicemia in buffalo calves in Pakistan, 31.48% mortality was recorded. Mortality significantly peaked on 8 th day (37%). Elevated body temperature (40.63+0.70°C), profuse salivation, dyspnea, respiratory sound "rales", ocular discharge, mucus nasal discharge and restlessness were observed. Grossly, head, neck and inter-mandible region were congested and edematous. Subserosal petechial hemorrhages throughout the body and blood-tinged fluid in thoracic and abdominal cavities were seen. Lungs showed pneumonic changes. Kidneys were swollen and hyperemic. There were petechial hemorrhages on the epicardium. Histopathologically, extensive lung edema, emphysema, thickened alveolar septa, congestion, and edema fluid in bronchioles were observed. Kidneys exhibited glomerulus atrophy, congestion, presence of casts in tubules along with pyknosis, condensation of nuclei and necrosis of tubular epithelium.
37 citations
01 Jan 2011
TL;DR: In this paper, the main objective of the study was to increase the delignification of sugarcane bagasse by using suitable concentration of KOH after specific heating time for efficient enzymatic hydrolysis and ethanol produc
Abstract: Objective: The major objective of this study was to increase the delignification of sugarcane bagasse by using suitable concentration of KOH after specific heating time. Materials and Methods: Pretreatment of sugarcane bagasse was done in 250 ml conical flask containing ten grams of chopped bagasse mixed with various concentrations of KOH in ratio of 1:10 (solid to liquid) for various time of heating at 121oC and 15lb psi. After heating the slurry was filtered, washed and then dried. The dried biomass was analyzed for delignification. Changes in structure was also observed microscopically (SEM) and spectroscopically (FTIR) leading to enhance the enzymatic digestibility of the sugarcane bagasse. Results: Maximum delignification (70.7%) was achieved with 2.5% KOH at autoclaving time of 45 min. Total sugars (192.32 mg/ml) released with 1.5% KOH at 30 min of autoclaving time and maximum weight loss (57.4%) was observed with 4% KOH at autoclaving time of 15 min. Conclusion: Alkaline treatment by using KOH of lignocellulosic materials caused swelling, leading to an increase in internal surface area, a decrease in the degree of polymerization, a decrease in crystallinity, separation of structural linkages between lignin and carbohydrates, and disruption of the lignin structure. For efficient enzymatic hydrolysis and ethanol produc
34 citations
TL;DR: In this article, the authors used Aslamazov-Larkin (AL) and Lawrence-Donaich (LD) equations to analyze the fluctuation induced conductivity (FIC) of Co-doped Cu 0.5Tl0.5Ba2Ca2Cu3−y
Abstract: Fluctuation Induced Conductivity (FIC) of Co-doped Cu0.5Tl0.5Ba2Ca2Cu3−y
Co
y
O10−δ
(y=0, 0.05, 0.1, 0.5) Superconductors have been studied as to find the possible cause of T
c suppression in these compounds. We used Aslamazov–Larkin (AL) and Lawrence–Donaich (LD) equations to analyze the FIC of our samples. In this regard, it is observed that the data seems to fit well with 3D (three-dimensional) AL equations. In addition, crossover temperature from 2D to 3D has been found. The width of the temperature window for 3D conductivity is continuously decreasing with enhanced Co concentration. The shrinking of 3D temperature region with increased Co doping can be correlated with the suppression of superconductivity. It is observed that the coherence length and th interplanar coupling strength have also been decreased with increased Co doping, consistent with the magnetic pair-breaking effect.
18 citations
Patent•
10 Nov 2011
TL;DR: In this paper, the authors describe the absorption of CO2 from a gas mixture by contacting the gas mixture with an absorption medium comprising at least water as a solvent and at least one amine of the formula (I) in which R1 is an aliphatic radical having 2 to 6 carbon atoms and at most one amino group, and R2 is hydrogen, a C1-4-alkyl radical or an R1 radical.
Abstract: CO2 is absorbed from a gas mixture by contacting the gas mixture with an absorption medium comprising at least water as a solvent and at least one amine of the formula (I) in which R1 is an aliphatic radical having 2 to 6 carbon atoms and at least one amino group, and R2 is hydrogen, a C1-4-alkyl radical or an R1 radical.
17 citations
TL;DR: A bit-rate and modulation-format independent optical cross-connect architecture that supports arbitrary spectrum allocation and transparent time multiplexing that is dynamic and can be reconfigured to meet the routing requirements of the network traffic is proposed and demonstrated.
Abstract: An experimental demonstration of gridless spectrum and time switching is presented. We propose and demonstrate a bit-rate and modulation-format independent optical cross-connect architecture, based on gridless spectrum selective switch, 20-ms 3D-MEMS and 10-ns PLZT optical switches, that supports arbitrary spectrum allocation and transparent time multiplexing. The architecture is implemented in a four-node field-fiber-linked testbed to transport continuous RZ and NRZ data channels at 12.5, 42.7 and 170.8 Gb/s, and selectively groom sub-wavelength RZ channels at 42.7 Gb/s. We also showed that the architecture is dynamic and can be reconfigured to meet the routing requirements of the network traffic. Results show error-free operation with an end-to-end power penalty between 0.8 dB and 5 dB for all continuous and sub-wavelength channels.
TL;DR: An adaptive gridless OXC is implemented using a 3D-MEMS optical backplane plus optical modules (sub-systems) that provide elastic spectrum and time switching functionality that is shown to provide suitable architectures on demand for three scenarios with increasing traffic and switching complexity.
Abstract: An adaptive gridless OXC is implemented using a 3D-MEMS optical backplane plus optical modules (sub-systems) that provide elastic spectrum and time switching functionality. The OXC adapts its architecture on demand to fulfill the switching requirements of incoming traffic. The system is implemented in a seven-node network linked by installed fiber and is shown to provide suitable architectures on demand for three scenarios with increasing traffic and switching complexity. In the most complex scenario, signals of mixed bit-rates and modulation formats are successfully switched with flexible per-channel allocation of spectrum, time and space, achieving over 1000-fold bandwidth granularity and 1.5 Tb/s throughput with good end-to-end performance.
18 Sep 2011
TL;DR: An adaptive gridless OXC is demonstrated using field fiber that adapts its architecture on demand to switch variable type signals in frequency, time and space domain with 1000-fold bandwidth granularity and 1.5 Tb/s throughput.
Abstract: An adaptive gridless OXC is demonstrated using field fiber. The OXC adapts its architecture on demand to switch variable type signals in frequency, time and space domain with 1000-fold bandwidth granularity and 1.5 Tb/s throughput.
01 Jan 2011
TL;DR: The protein contents were estimated in Candida utilis biomass which indicated its potential ability to improve the nutritional problems of protein deficiency associated malnutrition.
Abstract: 2 Abstract: In the present study Candida utilis was employed for the production of single cell protein (SCP) from wheat bran using solid state fermentation in 250ml Erlenmeyer flask. Various cultural conditions were also optimized for the maximum yield of cell biomass of Candida utilis. Maximum cell biomass was obtained when wheat bran was supplemented with 2% molasses as carbon and 0.25% ammonium nitrate as nitrogen sources and 250mg/L of Biotin as inducer at pH 6.5. The incubation period of 4 days was found suitable for maximum cell biomass of Candida utilis with 10% (v/v) inoculum size. The protein contents (48%) were also estimated in Candida utilis biomass which indicated its potential ability to improve the nutritional problems of protein deficiency associated malnutrition.
TL;DR: In this article, two different strains of Rhizopus sp. i.e. R. oligosporus -M30 and R. arrhizus-M26 were employed for the production of acid protease using different agro-residues such as rice husk, rice bran, wheat bran and defatted soybean meal as a sole carbon source.
Abstract: Two different strains of Rhizopus sp. i.e. R. oligosporus -M30 and R. arrhizus -M26 were employed for the production of acid protease using different agro-residues such as rice husk, rice bran, wheat bran, defatted soybean meal and sunflower meal as a sole carbon source. R. oligosporus -M30 gave maximum enzyme level with soybean meal (15.6 U/gds) while R. arrhizus -M26 with sunflower meal (13.6 U/gds) respectively. The optimal conditions for the enzyme production by R .oligosporus -M30 were initial pH of 5.5, temperature 30 oC with 10% of inoculum size for 72hr of fermentation period. When R. arrhizus -M26 was cultivated that exhibit the best enzyme production with the fermentation period of 72h, initial pH 5.0, temperature 33 oC with 5% of inoculum size
Patent•
10 Nov 2011
TL;DR: Ge-doped superconductors have been synthesized at normal pressure through solid state reaction method in this paper, which shows an enhancement in the critical temperature as well as magnitude of diamagnetism.
Abstract: Ge-doped (Cu0.5Tl0.5)Ba2Ca3(Cu4-yGey)O12-δ (y = 0, 0.3, 0.6 and 0.9) superconductors have been synthesized at normal pressure through solid state reaction method. Ge has been doped in the CuO2 planes constituting the superconducting block of these structures. In the as-prepared samples, a suppression of the critical temperature is observed with increased Ge concentration. The suppression of the critical temperature can be attributed to the decreased number of carriers due to their localization at Ge4+ ions. Ge-doped post-annealed samples have shown enhancement in the critical temperature as well as magnitude of diamagnetism. Oxygen annealing seems to have replenished the charge carries through the process of hole doping in CuO2/GeO2 planes, thereby bringing the carrier density closer to the optimum level. Oxygen related phonon modes have also been investigated. A shift in peak positions of the apical and planar oxygen related modes have been observed while modes associated with Oδ oxygen atoms seem stable in both cases of Ge doping and oxygen annealing.
TL;DR: In this paper, the authors summarized recent developments in continuous flow heterogeneous catalytic hydrogenation reactions using molecular hydrogen and provided an overview of the available flow hydrogenation techniques, reactors, commonly used catalysts and examples of synthetic applications with an emphasis on laboratory-scale Flow Hydation reactions.
Abstract: Microreactor technology and continuous flow processing in general are key features in making organic synthesis both more economical and environmentally friendly. Heterogeneous catalytic hydrogenation reactions under continuous flow conditions offer significant benefits compared to batch processes which are related to the unique gas-liquid-solid triphasic reaction conditions present in these transformations. In this review article recent developments in continuous flow heterogeneous catalytic hydrogenation reactions using molecular hydrogen are summarized. Available flow hydrogenation techniques, reactors, commonly used catalysts and examples of synthetic applications with an emphasis on laboratory-scale flow hydrogenation reactions are presented.
Patent•
10 Jun 2011
TL;DR: In this article, CO2 wird aus einer Gasmischung absorbiert durch in Kontakt bringen der Gasmichung with einem Absorptionsmedium, das zumindest Wasser als Losemittel und mindestens ein Amin der Formel (I)aufweist, worin R 1 ein aliphatischer Rest with 2 bis 6 Kohlenstoffatomen and mindesten einer Aminogruppe ist and R 2 Wasserstoff, ein
Abstract: CO2 wird aus einer Gasmischung absorbiert durch in Kontakt bringen der Gasmischung mit einem Absorptionsmedium, das zumindest Wasser als Losemittel und mindestens ein Amin der Formel (I)aufweist, worin R1 ein aliphatischer Rest mit 2 bis 6 Kohlenstoffatomen und mindestens einer Aminogruppe ist und R2 Wasserstoff, ein C1-4-Alkylrest oder ein Rest R1 ist.
Dissertation•
01 Aug 2011
TL;DR: Suhu and kelembaban ideal yang dibutuhkan telur pada saat proses pengeraman berkisar roughly 36oC - 40oC as mentioned in this paper.
Abstract: Suhu dan kelembaban ideal yang dibutuhkan telur pada saat proses pengeraman berkisar
antara 36oC - 40oC dan kelembabannya berkisar antara 55% - 65%. Tujuan dari penelitian ini
ialah mengimplementasikan pengontrol suhu dan kelembaban untuk tempat pengeraman telur
ayam agar dapat meningkatkan persentase penetasan telur. Pengontrol ini dibuat agar
pengeraman telur manual menjadi otomatis. Sistem ini akan menjaga suhu dan kelembaban tetap
ideal sesuai dengan yang dibutuhkan. Pengujian yang dilakukan dalam penelitian ini antara lain
adalah kalibrasi antara suhu dan kelembaban yang menggunakan pengukur suhu dan kelembaban
standard dengan suhu dan kelembaban yang diterima oleh sensor yang digunakan. Juga dilakukan
pengujian perbedaan antara menggunakan pengontrol yang dibuat dengan pengontrol yang lain, diketahui seberapa bergunanya pengontrol yang dibuat. Dari penelitian ini didapatlah
kesimpulan bahwa dengan menggunakan pengontrol, persentase keberhasilan dari penetasan telur lebih baik dibandingkan dengan pengontrol lain.
TL;DR: Since the use of manual BP measurement using mercury sphygmomanometer is still considered as gold standard of BP measurement, it is important that studies in which the BP outcome is measured using such method conduct interrater reliability studies properly.
Abstract: Background : To ensure the reliability of manual blood pressure (BP) readings in a clinical trial, sources of error due to measurement must be reduced as much as possible. Apart from following standard procedure for BP measurement and ensuring good equipments, the measurement errors that come from the assessors themselves should be assessed. Objective : To demonstrate the use of two-way random effects, interactions absent, absolute agreement (Type A), single measures (Type 1) intraclass correlation coefficient (ICC) in the assessment of reliability of manual BP readings among assessors involved in a clinical trial using manual BP measurement, by using an interrater reliability study conducted by the authors as an example study. Methods : The steps involved in obtaining ICC in the study were discussed. Sample size given the number of assessors in the study was calculated. BP was measured using regularly maintained mercury sphygnomanometers, following recommendations by Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) for BP measurement in office setting. The outcomes were systolic and diastolic BP readings. A type of ICC, two-way random effects, interactions absent, absolute agreement (Type A), single measures (Type 1) ICC was chosen for the analysis and specifically discussed. Pre-requisite assumptions for ICC were meticulously checked and described. The interrater reliability for systolic and diastolic BP readings as expressed by ICC (single measure) were presented with confidence interval (CI). The ICCs obtained in the example study were discussed and concluded. The flaws of the study were also criticised. Results : The interrater reliability for systolic and diastolic BP measurements as expressed by ICC (single measure) were 0.87 (95% confidence interval [CI] 0.722, 0.956) and 0.77 (95% CI 0.560, 0.918) respectively. Conclusion : We demonstrated the steps required to obtain ICC. Since the use of manual BP measurement using mercury sphygmomanometer is still considered as gold standard of BP measurement, it is important that studies in which the BP outcome is measured using such method conduct interrater reliability studies properly.