this paper, we will prove the following theorem, Let R be a ring with 1 having
a reverse derivation d ≠ 0 such that, for each x R, either d(x) = 0 or d(x) is
invertible in R, then R must be one of the following: (i) a division ring D, (ii) D 2 ,
the ring of 2×2 matrices over D, (iii) D[x]/(x ) 2
where char D = 2, d (D) = 0 and
d(x) = 1 + ax for some a in the center Z of D. Furthermore, if 2R ≠ 0 then R = D 2 is
possible if and only if D does not contain all quadratic extensions of Z, the center of
D.

The main purpose of this paper is to study some results concerning reduced ring with another concepts as semiprime ring ,prime ring,essential ideal ,derivations and homomorphism ,we give some results a bout that.

     In this paper, the structure of  and  have  been introduced and studied. We also obtain that a is  of a  if and only if there exists an  on such that . In addition, we obtain  that  of if and only if there is an   on  such that  , where  are subspaces of  with eigenvalues 1 and  −1, respectively. We also find  t that the existence of  on  implies that there exists a compatible  under appropriate condition.

Intervention in the criminal case requires examining the evidence examining  the  identity  of  the accused, and  preparing  him  with  all  the  necessary  elements  to  issuing  the  verdict, and  in  view  of  the  procedures that  this  research  takes,  which  may  extend  for  a long  time, thinking  has  turned  toward  dealing  with  the  criminal  case  without  the  criminal  judiciary, and this call  has  escalated  with  the trend  to  give  the  victim  an  important role in

Back ground : Coronary artery diseases are not uncommon in the presence of right bundle branch block.
Aim : The aim of this study is to assess the findings of coronary angiography in patients with chest pain and right bundle branch block.
Methods : The study involved review of case sheets and coronary angiography of one hundred patients, who underwent coronary angiography due to chest pain suspected to have
coronary artery diseases (CAD) , fifty patients of them had right bundle branch block (RBBB) , the other fifty did not have RBBB , those 100 patients were presented to Ibin Al Bitar hospital
for cardiac surgery from January 2004 to June 2006. History, clinical examinations, electrocardiogram (ECG)

In this paper we study necessary and sufficient conditions for a reverse- centralizer of a semiprime ring R to be orthogonal. We also prove that a reverse- centralizer T of a semiprime ring R having a commuting generalized inverse is orthogonal

The purpose of this paper is to prove the following result: Let R be a 2-torsion free ring and T: R?R an additive mapping such that T is left (right) Jordan ?-centralizers on R. Then T is a left (right) ?-centralizer of R, if one of the following conditions hold (i) R is a semiprime ring has a commutator which is not a zero divisor . (ii) R is a non commutative prime ring . (iii) R is a commutative semiprime ring, where ? be surjective endomorphism of R . It is also proved that if T(x?y)=T(x)??(y)=?(x)?T(y) for all x, y ? R and ?-centralizers of R coincide under same condition and ?(Z(R)) = Z(R) .

Nilpotency of Centralizers in Prime Rings

In this paper we define and study new concepts of fibrewise topological spaces over B namely, fibrewise near compact and fibrewise locally near compact spaces, which are generalizations of well-known concepts near compact and locally near compact topological spaces. Moreover, we study relationships between fibrewise near compact (resp., fibrewise locally near compact) spaces and some fibrewise near separation axioms.