In this paper, we discuss gravitational collapse of spherically symmetric spacetimes. We derive a general formalism by taking two arbitrary spherically symmetric spacetimes with g 00 = 1. Israel's junction conditions are used to develop this formalism. The formulae for extrinsic curvature tensor are obtained. The general form of the surface energy-momentum tensor depending on extrinsic curvature tensor components is derived. This leads us to the surface energy density and the tangential pressure. The formalism is applied to two known spherically symmetric spacetimes. The results obtained show the regions for the collapse and expansion of the shell.

Background:Articular cartilage normally functions as a load-bearing resistant material in joints. Patella is composed of hyaline cartilage and spongy bone. Chondrocytes form only 1–5% volume of the articular cartilage. They receive their nutrition by diffusion through the matrix. The alteration in articular cartilage become apparent following immobilization, from 4 to 6 weeks. Until now, focus of research has been the whole cartilage. Zonal changes have not been studied in detail. Since superficial zone bears maximum load and is the first zone to come in contact, the present study was designed to determine changes in thickness on immobilization and remobilization in superficial zone after dividing it into proximal, central, and distal segments.Materials and Methods:Forty male rats belonging to Sprague Dawley strain were divided into two groups. Group 1 (n=20) subdivided into an experimental subgroup of 10 rats that were immobilized in plaster of Paris (POP) for 4 weeks and a control subgroup of 10 that were not immobilized. Group 2 (n=20) subdivided into an experimental subgroup of 10 rats that were immobilized for 4 weeks and remobilized for next 4 weeks and a control subgroup of 10 animals that were not immobilized. At the end of the experimental period, the knee joint was dissected and was cut in sagittal plane. The section was fixed in 10% formalin for 48 hours. Specimen was decalcified using ethylenediaminetetraacetic acid (EDTA). The paraffin blocks of 7 μm sections were cut and stained by H and E stain for routine histology and Alcian blue stain and Mallory Trichrome for fine structural microscopy. The zones were named as superficial transitional, radial, and hypertrophic according to the shape of cells present in each zone. The superficial zone was divided into superior part, central, and inferior parts. These parts were labeled as central, proximal, and distal segments. The calibrated stage micrometer was used to calibrate the ocular micrometer under objectives of different power. The ocular micrometer was placed inside the ocular lens. It was calibrated with the stage micrometer under objective lenses of different power. The number of divisions of ocular covering each zone was calculated. These divisions were converted into micrometer and the actual thickness was calculated.Results:The significant decrease in thickness of superficial zone in proximal, central and distal segment was observed in experimental group in comparison to control group. When the experimental subgroup of group 2 was compared with experimental subgroup of group 1 (group immobilized for 4 weeks), no significant reversal was seen in superficial zone and instead significant decrease was observed in distal segment. Fibrous connective tissue was increased adjacent to superficial zone.Conclusion:Each segment of superficial zone behaves differentially on immobilization and remobilization. Perhaps a much longer duration of remobilization is required to reverse changes of immobilization in articular cartilage and plays a significant role in...

Summary: Central neuraxial block is an extensively implemented Introduction:Central neuraxial anaesthesia is the sensory neural transmission blockade using local anaesthetics and other additives. It is performed by putting the blocking agents in the vicinity of spinal neural tissues. For spinal anaesthesia (subarachnoid block, SAB) a deliberate lumber puncture (LP) occur below L 1 in adults (L 3 in child) to access the subarachnoid space avoiding the needle trauma to the cord. 1 Epidural or extradural anaesthesia offers a wider range of applications throughout the dorsal vertebral column.

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and than (318± 26.39). Total duration of analgesia in mins. Pre-emptive high dose rectal paracetamol appears to be more effective than diclofenac sodium suppository for postoperative analgesia in children undergoing tonsillectomy.

Third year BDS Ibad-ur-Rehman 3 First year MBBS ABSTRACT:The medical educationists are emphasizing on the implementation of skills based curriculum which covers the oral health in a broader and global scale. Keeping in mind these things this study was conducted to know opinion of medical students regarding modern educational reforms and the present curriculum taught in their medical colleges. Methodology: This survey was done in medical colleges with four year program in dentistry in Rawalpindi and Islamabad. A four-question survey about the format and characteristics of the dental curriculum was circulated among the 200 dental graduates graduating in the year 2014 belonging to different dental colleges in Rawalpindi and Islamabad. The respondents expressed their answers in yes or no. Respondents indicated the name of their school and answered survey questions. Descriptive statistics including percentage distribution for each response were used. Responses were recorded separately for all the four years. Results: In response to the question about integration between oral diseases with systemic disease, almost all agreed that their curriculum is disjointed in first and second year. 40% of the students told that some integration is created in third and 30% agreed that the integration is there in fourth year. 20% said that the basic sciences were taught with clinical context in first and second year and was not done in third and fourth year. Exposure of dental students to community and public health services was around 20% in third year and 30% in fourth year. PBL and case based discussions are not used in the dental colleges in all years. Conclusions: The dental curriculum in Pakistan needs to cover a much broader spectrum of diseases as well as patients. Linking the curriculum with modern tools like PBL can improve dental education. The link between the basic and clinical teaching and incorporation of community health can lead to marked shift in educational approach of the medical students.

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