A study of the photolysis of cyanocobalamin (vitamin B12) (B12), aquocobalamin (B12a) and hydroxocobalamin (vitamin B12b) (B12b) in the presence of ascorbic acid (vitamin C) (AH2) has been carried out in the pH range 2.0-12.0 using a visible radiation source. It involved the development of a multicomponent spectrophotometric method for the simultaneous determination of B12, its photoproduct aquocobalamin (B12a)/hydroxocobalamin (B12b), and AH2 at 550, 525 and 265 nm (pH 4.0). These wavelengths correspond to the absorption maxima of the three compounds and thus provide high specificity and sensitivity to the method. The method has been validated with respect to various analytical parameters. The recovery of the method for the three compounds ranges from 97.1-103.0% with a RSD value of ± 3%. The accuracy of the analytical method has been shown by the linearity of the kinetic plots in the concentration range studied. The method is simple, rapid and convenient for the purpose of assay and can also be used for the determination of B12 and B12b only at 550 and 525 nm in photolysed solutions. B12b only in the presence or absence of AH2 in photolysed solution can be determined at 525 nm. The photolysis of B12 and B12a/B12b in the presence of AH2 at pH 2.0-12.0, under aerobic conditions, follows first-order kinetics and the values of apparent first–order rate constants (kobs) at pH 2.0 to 12.0 range from 0.37–2.63×10–4 s–1 and 0.21–6.35×10–4 s–1, for B12 and B12a/B12b, respectively. The second–order rate constants (k2) for the photochemical interaction of AH2 and B12 and AH2 and B12a/B12b range from 0.20 (pH 2.0)–1.09 ×10–2 M–1s–1 (pH 5.0) and 5.88 (pH 2.0)–91.08 ×10–2 M–1s–1 (pH 5.0), respectively. The values of the k2 for AH2– B12a/B12b interaction are 30–80 times greater than those of AH2–B12 suggesting a greater susceptibility of B12a/B12b to photodegradation compared to that of B12 in this pH range. The k2–pH profiles for both B12 and B12a/B12b are bell–shaped curves indicating the effect of AH2 ionization on the rates of their interaction. The complete discoloration of B12 and B12a/B12b solutions on prolonged photolysis indicates the formation of corrin ring cleavage (oxidation) products in acid and alkaline solutions. These oxidation products do not absorb in the visible region and, therefore, do not interfere with the assay of B12 and B12a/B12b in the visible region. Reaction schemes for the mode of photodegradation of B12 and B12b in the presence of AH2 have been presented. The involvement of a short lived ligand-to-metal charge transfer (LMCT) intermediate state in the photolysis of B12 and the formation of different singlet states, on the photoexcitation of B12a/B12b, leading to the photodissociation of Co-OH bond by different mechanisms have been suggested. The photolysis of B12-cysteine and B12a/B12b-cysteine complexes has also been studied in the pH range 2.0-12.0 using a two-component spectrometric method by absorpbance measurements at 550 and 531 nm, the absorption maxima of B12-CY and B12b-CY complexes, respectively. The kinetics of these systems has been evaluated and the association constants for these complexes have been determined. The photolysis of B12 and B12b in the presence of ferrous ions has also been studied and the second-order rate constants for their photochemical interaction have been determined. The rates of interaction are affected by the pH of the medium as a result of the conversion of Fe2+ ions to Fe (OH)2 above pH 5.0.
پروفیسر سید احتشام حسین پروفیسر سید احتشام حسین صدر شعبۂ اردو الٰہ آباد یونیورسٹی کی ناگہانی وفات علمی و ادبی دنیا کا بڑا سانحہ ہے، مرحوم اس دور کے چوٹی کے ادیبوں اور نقادوں میں تھے، ترقی پسند ادب کے تو معلم و رہنما تھے، اس دور کے نوجوان ادیبوں کی پوری نسل ان سے متاثر ہوئی، جدید ادب کے ساتھ قدیم ادبیات پر بھی ان کی نظر بڑی گہری، اور مبصرانہ تھی، اور وہ اس کی اچھی روایات کے بھی قدرشناس تھے، لسانیات سے بھی واقف تھے، انھوں نے سیکڑوں ادبی و تنقیدی مضامین اور بعض مستقل کتابیں لکھیں، اگرچہ وہ ترقی پسندوں کے امام تھے لیکن ان کے خیالات میں بڑا اعتدال و توازن اور زبان و قلم دونوں میں بڑی شایستگی تھی، اس لئے جدید کے ساتھ قدیم طبقہ میں بھی ان کی بڑی قدر تھی، وہ ابتداء میں لکھنؤ یونیورسٹی کے شعبۂ اردو کے لکچر مقرر ہوئے اور تقریباً ۱۵- ۱۶ سال اس عہدہ پر رہے، پھر الٰہ آباد یونیورسٹی اردو کے صدر ہوگئے تھے، اردو کی تمام اہم مجالس کے ممتاز رکن تھے، کوئی اہم ادبی اجتماع ان کے بغیر کامیاب نہ سمجھا جاتا تھا، انھوں نے مختلف حیثیتوں سے اردو کی بڑی قیمتی خدمات انجام دیں اور ہر محاذ پر اردو کے مخالفین کا مقابلہ کیا۔ ان علمی کمالات کے ساتھ وہ طبعاً بڑے متین، سنجیدہ، شریف اور وضعدار تھے، ان کے علم سے زیادہ ان کے اخلاق و شرافت کا اثر پڑتا تھا، دارالمصنفین سے ان کو دہرا تعلق تھا، ایک علمی و ادبی دوسرا وطنی، ماہل ضلع اعظم گڑھ ان کا وطن تھا، ہائی اسکول تک ان کی تعلیم بھی اعظم گڑھ میں ہوئی تھی، اسی زمانہ سے ان کو دارالمصنفین سے تعلق تھا، جو ہر زمانہ میں یکساں قائم رہا، جب تک وہ لکھنؤ میں رہے، اکثر ان...
تهدف الدراسة لتحليل حديث ابن عمر -رضي الله عنهما- في المبيت في مِنَى، والذي يعدُّ أصلا في مسألة المبيت ودارت عليه فتاوى الائمة الفقهاء. اتبع الباحث منهجاً واضحاً في إعداد تمثل في عزو الايات القرآنية لسورها، وتخريج الأحاديث من كتب السنة المعتبرة، والاستعانة بأقوال العلماء وشراح الحديث في فقه الحديث وشرحه، وعزو الأقوال لمصادرها الأصلية ما وسعني ذلك، أو بواسطة عند الحاجة. وتوصلت الدراسة إلى مجموعة من النتائج أهمها وجوب المبيت بمنى على الحاج، ومَن ترك المبيت ليلة فلا شيء عليه، ومن ترك المبيت بالكلية فيلزمه دم لتركه منسكا من المناسك، ومَن لم يجد مكانا بمنى فيبيت بأقرب مكان لها مراعاة لاتصال الحجيج.
الكلمات المفتاحية: حديث ابن عمر، المبيت في مِنى، اركان الإسلام، السيرة النبوية، السنة النبوية.
The struggle to develop an ideal model for teaching English language has been going on for so many years. English language is the second language in many countries including developing countries like Pakistan. In Pakistan English language has emerged as a powerful medium for communication and learning this language has become the need of the hour for a successful career and life. The students of the developing countries encounter many problems while speaking in English language and the major among those problems is the spoken English language anxiety which hinders the progress of the freshly graduates from getting good jobs.The main aim of the study was to explore confidence of students studying in the Pakistani context in their spoken English skill, with a focus on developing a model of active learning using interactive activities for language usage. It is based on the premise that social interaction is necessary for the cognitive development of mind, as emphasized by Vygotsky (Verenikina, 2010). This research is a mixed method study which was conducted in a private sector university of Lahore city in Pakistan. A quasi experiment Pre-test, post test design was conducted on an intact group of sixty students taken from the first semester. The intervention was based on interactive activities that lasted for two semesters or 32 weeks. The data was analyzed both qualitatively and quantitatively. The quantitative data was gathered through two standardized research tools i.e. a closed ended questionnaire and the spoken English assessment scale. The foreign language classroom anxiety scale developed by Elaine Horwitz (1986) and the adapted version of Conversational skills rating scale by Spitzberg (2007) were utilized for the present study. The qualitative data consisted of the researcher’s observations recorded during the intervention. Results of the study Effect of Confidence Enhancement Techniques on Spoken English showed that the students’ confidence level improved when they were exposed to interactive activities. The students of the control group showed no significant improvement as they had been taught by the routine methodology. Thus it is proposed that such interactive activities handled by trained instructors should be utilized in the classrooms, which can lead to the development of more confident English language speakers.