Acceptance of trial of labor after cesarean (Tolac) among obstetricians in the Western Region of Saudi Arabia: A cross-sectional study

BackgroundBabies to women eligible for trial of labor after a cesarean (TOLAC) are sometimes delivered by cesarean section (CS). To obtain clinicians’ attitudes and beliefs about TOLAC, this study was designed to investigate the views of clinicians when advising TOLAC-eligible pregnant women about TOLAC, and to explore their reasons in favor of or against TOLAC.MethodsInterviews were carried out individually (face-to-face) with clinicians using a specially designed questionnaire to collect data from obstetricians in the Western Region of Saudi. Regression analysis was used as appropriate.ResultsAmong the 183 obstetricians included in the current study, approximately 79.2% were against offering TOLAC. However, most of the physicians (89.1%) were in favor of offering TOLAC to patients who had had a successful vaginal birth after CS. significant associations were found between physicians’ opposition to TOLAC and medical and most non-medical factors.ConclusionClinicians should recognize that the critical role they play in the delivery decision-making process and in boosting women’s confidence in TOLAC may be key to increasing the rate of TOLAC.     

Late Bashkirian and early Moscovian conodonts from the Naqing section,Luodian, Guizhou,South China

Late Bashkirian and early Moscovian conodonts are abundant and diverse at the Naqing section, South China. All conodont genera known to have numerous species in the late Bashkirian–early Moscovian are recorded here, including Declinognathodus, Diplognathodus, Gondolella, Idiognathodus, Idiognathoides, Mesogondolella, Neognathodus, and Neolochriea. At Naqing, many species of these genera provide a succession of conodont chronomorphoclines throughout the Bashkirian–Moscovian boundary interval. They demonstrate that deposition was remarkably continuous through the boundary interval, a major criterion for selecting a Global Stratotype Section and Point (GSSP). This paper describes the current state of knowledge for several of these chronomorphoclines, and also provides an updated range chart of conodonts recovered from the Naqing section and their correlation with other regions.The taxon that best matches the current concept for the base of the Moscovian Stage in its type region is the phylogenetic first occurrence of Diplognathodus ellesmerensis. An ancestral form with most of the characteristics of D. ellesmerensis occurs at Naqing. More specimens are needed to completely document the chronomorphocline, but because D. ellesmerensis is found worldwide — including that close to the base of the type Moscovian — its evolutionary first occurrence would provide an almost ideal GSSP to define the base of the international Moscovian Stage.     

Determination of the Covariance of Random Sets from Thin Sections

The problem of stereological determination of the covariance of a random set from thin sections is considered. Using results of numerical experiments for two examples, a simple approximation formula is suggested.     

Expression of the phage λ recombination genes exo and bet under lacPO control on a multi-copy plasmid

The bacteriophage λ genes exo and bet, whose products (λ exonuclease and β protein, respectively; Red phenotype) mediate homologous recombination of λ phages, have been cloned under lacPOlacI^q control on multi-copy plasmids. Induction of recA3 cells harboring these plasmids with isopropylthiogalactoside (IPTG) resulted in λ exonuclease levels (assayed in vitro) that were proportional to the time of induction (for at least 4 h); recombination of λ Red^? phages in vivo was similarly inducible. Only one out of 25 bet^Δ plasmids (constructed by a variety of in vitro techniques) expressed λ exonuclease, a result consistent with the polarity of several known phage bet mutations. A general method for transferring phage exo and bet mutations to plasmids was devised and plasmids bearing polar (bet3) and nonpolar (bet113) mutations were constructed. Mutant derivatives of the plasmid showed the same complementation pattern as analogous phage red mutants. When λbet3 phages (Exo^?Bet^?) infected IPTG-induced recA3 bacteria containing exo⁺bet⁺ plasmids, recombination frequencies were no more than twice those typical for infection of plasmid-free recA3 cells with exo⁺bet⁺ phages, even in the case of IPTG induction sufficient to elevate the production of λ exonuclease about 100-fold. Even when plasmid induction was delayed till as late as 50 min after infection, recombination was significant. Preliminary experiments suggest that these plasmids encode a polypeptide with Gam activity that corresponds to the 98-amino acid “shorter” open reading frame assigned to gam by Sanger et al.     

胫骨中段横断面与年龄变化的研究

本文对218例1—94岁中国汉族人胫骨中段横断面的矢状径、横径、髓腔矢、横径及骨密质前、内、外缘,内、外、后面厚度等10项指标进行了测量分析。结果表明,胫骨中段矢状径、横径及骨密质相对厚度在1—30岁年龄阶段与年龄具有高度正相关性。髓腔平均直径在1—25岁年龄阶段亦呈规律性变化。