In modern logic, the logical implication between premises and the conclusion in any proof, and also the implication between negation of conclusion and its contradiction in indirect proofs are material implications whereas in ancient logic they have Lozomi relations. Besides, in indirect proofs, after assuming this Lozomi relation it is assumed that the conclusion itself is accidentally (in way of Ettefaghieh) conditioned to its negation and this relation is considered as the basis for the indirect proof. According to this research, this relation is firstly neither the basis of the indirect proof, for it is unnecessary, nor there is any need to assume it, and secondly the reason given for it is unacceptable. It will be also shown that the domain of application of the indirect proof in ancient logic has been over-extended. In addition, the application of the indirect proof in different formal structures is a factor of consistency and completeness of the structure, and so it has no use in multi-valued formal structures because it is based on the law of excluded middle.

Background and Objectives: Upper urinary tract is a common site for congenital malformations. Some of these malformations could be clinically silent for a long period of time and grow insidiously, and many of them must undergo surgical treatment. On the basis of previous findings, this study was performed to provide statistically adjustable incidence of upper urinary tract malformations in apparently asymptomatic individuals in order to justify the necessity of ultrasonography of kidneys and bladder and to investigate the above mentioned anomalies, particularly in pediatric group under 6 years of age. Materials and Methods: During a period of 2 years, 465 children and 535 adults, without any clinical suspicion of urinary problems were studied, initially by sonography and followed up by IVU or CT scan , as indicated.They were referred to the radiology and sonography center for evaluation such as chest X- Ray, sonography of liver and gall bladder or skull and limb radiography etc.Results: Upper urinary tract malformations were found in eighteen (4%) children and 17 (3%) adults by sonography alone, or by relevant sonography and IVU, CT scan or isotope scanning.Conclusion: According to the outcome of this study, we suggest that screening by sonography should be mandatory for everyone especially when they are under 6 years of age.

This study evaluated the relationship between the location of the most severe coronary artery stenosis and the subsequent acute myocardial infarction (AMI). Methods: Of 1590 patients who were admitted with a diagnosis of AMI, we identified 44 patients who had undergone previous myocardial perfusion SPECT. Thirty-one of these patients also had previous coronary angiography. The relationship between the location of the myocardial perfusion defects, the coronary artery stenosis and site of subsequent AMI were studied in these patients. Results: The concordance between the location of the most severe reversible defects detected by SPECT and the site of subsequent AMI was 71% (k=0.499). The concordance between the most severe stenosis detected by coronary angiography and the site of subsequent AMI was 64% (k=0.451). Conclusion: The culprit lesion is not always the one that is manifested by the most severe reversible perfusion defect or the most critical coronary stenosis. Myocardial SPECT and coronary angiography can peredict the location of a future AMI in 71% and 64% of patients respectively. The percentage is higher when the interval between investigations and subsequent AMI is <3 month, for moderate to severe perfusion defects and for 90-99% coronary stenosis

Angiofibrom is the most common benign tumor of nasopharynx. Because of site of its origin (Superior border of sphenopalatine foramen), this tumor can extend to nasal cavity, paranasal sinuses, ptrygomaxillary fossa, infratemporal and temporal fossa and Intracranium. The most common symptoms are epistaxis and nasal obstruction. Diagnosis is based on Physical findings and radiology, biopsy may cause fatal bleeding and is avoidedIn a 14 Year old male with a large angiofibroma of nasopharynx, that had extended to nasal cavity (bilaterally), right maxillary sinuse, right ptrygomaxillary and infratemoral fossa, sphenoid sinuse and intracranium (Through parasellar), we prefered to use LefortI osteotomy for removal of the tumor, Because This approach provide an excellent direct access to above regions without facial scarring. This approach for surgery of angiofibroma was Performed for first time in Medical University of Esfahan.

The service life of railway impregnated cross-ties in Iran is much lower than indicated in the International Standards. In this connection, some researchers believe that the moisture content of the timbers is not optimal prior to the treatment process. Therefore, the present study was conducted to study three different MC levels (12, 23, and 51%) to compare creosote retention as well as its penetration in impregnated samples, using Bethel method. Results show that there is no significant difference between 12 and %23 (below FSP) Moisture levels. Therefore that would be enough to decrease the MC to about %23 to insure the timbers would be properly impregnated with creosote, that is, there is no need to season the timber to as low as %12 MC. This would facilitate and simplify treatment process as well as increase the service life of the impregnated timbers, including those used in railway cross-ties.

Background: Blood exchange is one of therauputic methods for neonatal hyperbilirubinemia. But this method has some complications. One of these complications is hypocalcemia. In some studies, for avoiding from this problem, calcium gluconate injection is recomm ended. But in some studies there was any important difference between calcium treated group and the group without calcium prescription.Due to lack of documented evidences about prevalence of this complication, this study was conducted to compare the result of using calcium gluconate injection in the incidence of hypocalcemia and hyper calcemia.Methods and materials: For this purpose in a randomized controlled clinical trial in Ali_ Asghar pediatric hospital in Zahedan, 40 hyperbilirubin neonates that were hospitalized for blood exchange came into this study. These patients were randomized in two groups so that they were adjusted in terms and preterm delivery. For 22 patients, 1 ml of calcium glucdnate%10 was injected in each 100 ml exchanged blood and for 18 patients (control group), calcium injection wasn’t been done. Calcium serum level was tested before, immediately after and 6 hours after blood exchange in all patients. Data analysis was been done by means of fishers exact test, Chi_ Square and Binomial test.Results: In calcium treated patients, hypocalcaemia wasn’t being present after blood exchange. But in non _ calcium treated patients hypo calcemia was seen in 4 cases(%22.4) after blood exchange (P<0.013). All of these 4 cases were preterm. In calcium treated patients hypocalcaemia had a significant increase after exchange especially in term neonates (P<0.028).Conclusions: On the base of these results, in preterm neonates, calcium gluconate injection after blood transfusion exchange is recommended. But this procedure isn’t necessary in term newborns because may result in hyper calcemia.

Statement of Problem: The major objectives of root canal treatment are removal of all irritant from the root canal space and accomplish a proper shaping of the space and total obturaion of this space. So, diagnosis of root curvature is critical and can affect on proper preparation and prevention of procedural accidents.Purpose: The aim of this study was to measure and evaluate the root curvature of permanent teeth that were treated at Endodontic Department of Shiraz Dental School (2001-2002).Materials and Methods: In this case control study, all endodontic treated patients with standardized radiographic films to determine the working length were analyzed and the angel of root curvature, were evaluated by Schneider method. After image projection and drawing of two lines, one on long axis of the canal and the other from apical foramen to the first line, the constructed angel was measured.Results: From 398 evaluated films, the root curvatures in posterior teeth were more than that in anterior teeth. Most of the roots (80%) had root curvatures directed to the mesial or distal plane although root curvatures to distal plane were more common. All of the roots had mild to moderate curvatures (0-25 degrees) except the mesial root of the first mandibular molar that had severe root curvature (more than 25 degrees). The mean of root curvature of permanent teeth were between 2.76 to 28.28 degrees.Conclusion: The results indicated that root curvatures in teeth were common and practitioners should be aware in the case of any difficulty, and refer the case to a specialist.

Introduction: The issue of hypothyroidism following thyroidectomy is still under debate. Currently all patients receive thyroid hormones while most of them really do not require such treatment. This study looks at the incidence of hypothyroidism among patients who underwent thyroidectomy in a major referral hospital and examines possible risk factors. Materials and Methods: 102 patients who underwent thyroidectomy in Shariati Hospital were investigated for their thyroid function profile on five occasions: just before surgery and after surgery and then three times, on a 3-monthly interval, for one year. All patients whose tests indicated hypothyroidism, were given hormone replacement therapy. The treatment continued for 3 months after normalization of the tests. Results: Thirty men and 72 women were included in this study. Mean age of participants was 39±13.6 years (males: 40.5±14.2 and females: 38.4±5.1 years). Thirty-six patients developed hypothyroidism (35.2%) occurring on an average 5±3.2 months after surgery. Increased weight, operation type, histopathologic type (Graves disease and adenomatous goiter), underlying diseases (Graves disease and toxic multinodular goiter) and their duration, lymphocytic infiltration and use of levothyroxine before surgery were found to be associated with the incidence of hypothyroidism. On the contrary, no association between the occurrence of hypothyroidism and gender, grade of thyromegaly, post-surgical complications or immediate pre-surgical TSH level was seen. Conclusion: The investigation can serve as a pilot study for more extensive studies examing the issue in the future. Indicators such as Graves disease and lymphocytic infiltration in pathologic specimens may be used to predict the occurrence of hypothyroidism in patients undergoing thyroidectomy and limit the unnecessary usage of thyroid hormones.

Establishment of Value Added Tax in Iran can be surveyed from different aspects. This paper is intending to find an answer to this question that whether execution of VAT is necessary or not. This can be done, through a scientific approach. Thus, this can be made clear through a valuable, comparison which is based on a scientific logic. First we compare Iran's tax system with a world average and then with a survey on the components of the tax system, we pay attention to the needs of moving toward the establishment of VAT in Iran.The analysis of applying the results of this approach indicates that establishment of VAT in Iran as a whole can decrease the gap between the world average index and Iran's tax system in achieving the optimized tax index.