let $r$ be a reversible ring which is $alpha$-compatible for an endomorphism $alpha$ of $r$ and $f(x)=a_0+a_1x+cdots+a_nx^n$ be a nonzero skew polynomial in $r[x;alpha]$. it is proved that if there exists a nonzero skew polynomial $g(x)=b_0+b_1x+cdots+b_mx^m$ in $r[x;alpha]$ such that $g(x)f(x)=c$ is a constant in $r$, then $b_0a_0=c$ and there exist nonzero elements $a$ and $r$ in $r$ such tha...

we observe some new characterizations of $n$-presented modules. using the concepts of $(n,0)$-injectivity and $(n,0)$-flatness of modules, we also present some characterizations of right $n$-coherent rings, right $n$-hereditary rings, and right $n$-regular rings.

in this paper, we introduce the concept of the   generalized aip-rings as a generalization of the generalized quasi-   baer rings   and generalized p.p.-rings. we show that the class of the generalized aip-rings is closed under direct products and morita invariance. we also characterize the 2-by-2 formal upper triangular matrix rings of this new class of rings. finally, we provide sever...

this paper is an attempt to generalize, simultaneously, the ring of real-valued continuous functions and the ring of real-valued measurable functions.

OBJECTIVES Cardiovascular involvement is recognized as a poor prognostic factor in systemic sclerosis (SSc). The aim of this study was to evaluate the usefulness of nailfold video-capillaroscopy (NVC), brain natriuretic peptide (BNP) blood level and exercise echocardiography to predict the occurrence of cardiovascular events in SSc. METHODS We prospectively enrolled 65 patients with SSc (age ...

BACKGROUND Hemodynamics assessment is important for detecting and treating post-implant residual heart failure, but its accuracy is unverified in patients with continuous-flow left ventricular assist devices (CF-LVADs). OBJECTIVES We determined whether Doppler and 2-dimensional transthoracic echocardiography reliably assess hemodynamics in patients supported with CF-LVADs. METHODS Simultane...

Members of the family of surface adhesins of oral streptococci, including P1 of Streptococcus mutans, contain two highly conserved repeat domains, one rich in alanine (A region) and the other rich in proline (P region). To assess the contribution of the P region to the biological properties of P1, an internal deletion in spaP was engineered. In addition, the P region was subcloned and expressed...

BackgroundExercise stress echocardiography (SE) is increasingly recognized as a useful tool for assessment of pulmonary hypertension (PH) in patients with sickle cell disease (SCD). However, while the prognostic significance resting systolic artery pressure (SPAP) well established and global longitudinal right ventricular free wall strain (RV FWS) has been identified an independent marker PH, l...

Abstract Background Although echocardiographic surrogates of right ventricular -arterial coupling (RVAC) have been reported to be associated with outcome in patients moderate or severe secondary tricuspid regurgitation (STR), pulmonary artery systolic pressure (SPAP) is difficult estimated using echocardiography STR. Purpose Accordingly, we evaluated the predictive power indexes RVAC obtained R...

let $r$ be an associative ring with identity and $z^*(r)$ be its set of non-zero zero divisors.  the zero-divisor graph of $r$, denoted by $gamma(r)$, is the graph whose vertices are the non-zero  zero-divisors of  $r$, and two distinct vertices $r$ and $s$ are adjacent if and only if $rs=0$ or $sr=0$.  in this paper, we bring some results about undirected zero-divisor graph of a monoid ring ov...