Alginate is an exopolysaccharide composed of varying ratios of β-D mannuronic acid and its C5 epimer α-L-guluronic acid linked together by β-1,4 - glycosidic bond. It has wide range of industrial applications particularly in food sector as a viscosifier, stabilizer, thickener, emulsifier, gelling and water binding agent. Commercial alginate is extracted from brown algae but due to variation in composition of biopolymer isolated from species of different locations, there is growing interest in bacterial alginate. At present two strains of bacteria are reported to produce alginate, Pseudomonas and Azotobacter. Hence present study was designed to produce alginate by Azotobacter vinelandii utilizing cheap substrates to save the foreign exchange. To achieve the goal, different physiochemical parameters were optimized to have hyper-production of alginate through submerged fermentation. Different agricultural wastes like wheat bran, rice polishing and molasses were utilized as substrates through fermentation with Azotobacter vinelandii.On fermentation of 7.5% (w/v) wheat bran by A.vinelandii, maximum alginate production (5.21 g/L) was observed at 48 hours of incubation time with 6% (v/v) inoculum size, pH 7.0, 300C and agitation speed of 200 rpm. Addition of different optimum levels of ionic salts i.e. 1.5% CaCl2 and 2% MgSO4. 7H2O in the growth medium gave significantly (P< 0.05) higher quantity of alginate (6.08 g/L) where as addition of KH2PO4 and NaCl reduced the yield of alginate. Among different nitrogen sources tested, 2% corn steep liquor resulted significantly (P<0.05) higher yield of alginate (7.46 g/L). The bacterial strain was improved by exposure to physical (UV irradiation) and chemical mutagens (Nitrous acid and ethidium bromide) to obtain more than 90% killing. The survivors were screened for hyper-production of alginate against the wild strain of A.vinelandii using pre- optimized conditions. The highest alginate production (13.8 g/L) was obtained by the ethidium bromide treated strain (EtBr-02). The mutant strain was used for optimization of fermentation parameters. The maximum concentration of alginate (15.61 g/L) was obtained by utilizing 10% (w/v) wheat bran, 8% (v/v) inoculum at 48 hours of incubation, pH 7.0, 300C and an agitation speed of 200 rpm. Inclusion of 2.5% cornsteep liquor raised the alginate concentration to 15.8 g/L. Batch fermenter studies were carried out in 2 L fermenter with working volume of 1.5 L using the mutant strain A.vinelandii, EtBr-02. Optimization of process parameters like agitation, aeration and pH in the fermenter showed that maximum alginate (16.8 g/L) was achieved at 300 rpm, 2.5 vvm aeration and controlled pH condition at 32 hours of incubation time. The alginate produced was identified by FTIR spectrum after precipitation. The purity of alginate was estimated by HPLC against the standard alginic acid from Sigma-Aldrich and was found to be 98% pure. The alginate produced was used at 3% concentration for immobilization of yeast cells. Immobilized and free cells were compared for ethanol production using 10% sucrose as the carbon source in fermentation medium. The maximum amount of ethanol obtained was from free cells i.e. 38 g/L whereas immobilized cells produced 32.5 g/L ethanol. The advantage of immobilization is that beads can be reused in eight sequential fermentation cycles of 10 h each. Thus a cheap and practical bioprocess of alginate production was developed, that can be exploited commercially to save foreign exchange.
مسٹر چرچل بالآخر مسٹر چرچل کو بھی پیام اجل آگیا، وہ ا س صدی کی عظیم ترین شخصیتوں میں تھے، ان میں اتنے کمالات جمع تھے کہ مشکل ہی سے ایک انسان میں جمع ہوتے ہیں، وہ صحیح معنوں میں صاحب السیف و القلم بلکہ کچھ اس سے بھی زیادہ تھے، ایوان سیاست میں بے نظیر و مدبر، عرصۂ رزم میں جنگ آزما سپہ سالار میدان علم و ادب میں سحر طراز ادیب و خطیب، وہ اپنی قوم کے بہت بڑے محسن تھے، انھوں نے جتنی طویل مدت تک اپنے ملک و قوم کی خدمت کی اس کا موقع کم لیڈروں کو ملتا ہے، انھوں نے نوے سال کی عمر پائی اور ستر سال تک مسلسل کسی نہ کسی حیثیت سے خدمت کرتے رہے، وہ برطانوی قوم کے ناخدا تھے، انھوں نے ایسے نازک موقعوں پر اس کو ڈوبنے سے بچایا جب اس کی امید بہت کم رہ گئی تھی، گو وہ قدامت پرست طبقہ سے تعلق رکھتے تھے جس کا نقطہ نظر برطانوی شہنشاہیت کی توسیع و استحکام اور دنیا میں اس کی بالادستی تھا لیکن وہ اتنے بڑے آدمی تھے اور انھوں نے اپنی قوم کی اتنی گوناگوں خدمات انجام دیں کہ ان کی ذات دنیا کے لیڈروں کے لئے نمونہ ہے جس سے ان کو سبق حاصل کرنا چاہیے۔ (شاہ معین الدین ندوی،فروری ۱۹۶۵ء)
Transplantation of organs and its donation is a burning issue of the present time. It has been carried out in different ways for different purposes. No doubt, the medical field has a vital role in serving the human beings by introducing new means of treatments including the transplant of organs. In Islamic point of view the transplantation and donation of human organs is lawful only when it follows the objectives of Shariah. The human dignity is to be maintained in every movement of life. If practicing the transplant leads to human destruction and violation of its prestige and honor or paves the path to kidnapping, bargaining and immorality, then it should be avoided. Donation of organs, under the supervision of strict regulatory authority, will be beneficial. In this article, Islamic perspective on this issue has been brought forth.
The radiation therapy field is advancing continuously to achieve higher degrees of accuracy and efficiency. An optimized radiotherapy treatment planning guarantees the achievement of the treatment goals. The intent of this dissertation was to investigate quality of Intensity Modulated Radiotherapy (IMRT) treatment plans through analysis of dose volume histograms, Simultaneous Integrated Boost (SIB) IMRT and RapidArc plan verification using gamma index, and the analysis of wedge-shaped beam profile parameters with the viewpoint of optimizing the accuracy of the processes involved. This work has been split into three components with the same focus of attention of verifying and improving the quality assurance procedure. Firstly, dose conformity and homogeneity of IMRT plans for pelvic cancer patients had been explored. Then evaluation of pre-treatment dose verification was performed for H&N and cervix cancer patients by using gamma index. Lastly, analysis of wedge-shaped isodose curves has been determined to verify quality of radiation beams used. Firstly, this study aimed to investigate degree of conformity and homogeneity for pelvic patients using IMRT technique. Three different formulas of Conformity Index (CI) and four formulas of Homogeneity Index (HI), described in literature were analyzed using 15MV photon beam. In total, 18 patients were selected at random and dose of 5000 cGy was delivered in 25 equal fractions. CI suggested by International Commission on Radiation Units and Measurements (ICRU), Radiation Conformity Index (RCI) and CI PITV had mean ± standard deviation values of 1.02 ± 0.018, 0.98 ± 0.017, and 1.63 ± 0.333, respectively. Values of CI PITV exceeded acceptable value for 27% patients with minor deviation. Mean ±SD of HI A, HI B, HI C and HI D were 1·12±0·02, 0·13± 0·04, 0·10±0·02 and 0·99±0·03, respectively. Coefficient of determination between each set of HI values was known by calculating R2 value. No statistically significant differences were observed for three CIs reported. All the studied HIs can be effectively used for assessment of uniformity inside the target volume. However, values of HI C were closest to ideal value as compared with other three formulas; hence, it is considered a better measure to compute homogeneity of dose within target volume. 8 Secondly, this study aimed to estimate point-by-point difference between measured and calculated dose distribution in terms of both Distance to Agreement (DTA) and Dose Difference (DD) by using gamma analysis. Gamma evaluation was performed for dose verification of SIB IMRT and RapidArc plans. The portal dosimetry software (Varian Medical Systems, Palo, Alto, CA) performed gamma analysis. The dose difference and distance to agreement criteria can be defined individually. All gamma calculations were based on 3 mm DTA and 3% DD criteria for RapidArc plans and 3 mm DTA and 5% DD criteria for SIB IMRT plans. Plans of this study were deemed acceptable when passing rate was 95%. Thirteen SIB IMRT and all RapidArc cases pass tolerance criteria of 95% set by our institution. Findings of this work underlined the importance of gamma analysis method to predict the quality of dose calculation. Passing rate of 95% is achieved in 93% of SIB IMRT and for all RapidArc plans which is adequate level of accuracy for analyzed plans thus assuring the robustness of gamma analysis technique. Lastly, this exploration was intended to analyze photon beam profile parameters; symmetry, Central Axis (CAX) deviation, Field 50%, left and right penumbra, Dmin, Dmax, and homogeneity for 6 MV and 15 MV photon beam energies of wedge-shaped isodose curves to improve the efficiency of treatment plans. Treatment parameters like depth, wedge angle, and field size were varied to observe their effect on dosimetric characteristics of beam profiles in a water phantom, generated by Varian Clinac linear accelerator. It was concluded that these beam profile characteristics precisely agreed with the acceptance criteria as recommended by the radiotherapy protocols with very slight deviation. Wedge angle, field size, and depth dependency on wedge-shaped isodose curves should be taken into account to prevent any significant tumordose discrepancies for the cancer patients.