Retraction Ring Research Articles

Insights into the Thermal Eliminations and Photoeliminations of B,N-Heterocycles: A Theoretical Study.

Understanding the photochemistry of organoboron compounds is essential to expand optoelectronic applications. In this work, the complete active space self-consistent field (CASSCF) and its second-order perturbation (CASPT2) methods combining with density functional theory (DFT) have been employed to investigate the elimination mechanisms of compound 6,7-dihydro-54-benzo[d]pyrido[2,1-f][1,2]azaborininr (B4) on the ground state (S0) and the first excited state (S1). B4 is one of the 1,2-B,N-heterocycles that undergo competitive thermal elimination and photoelimination depending on the substitution groups on the B atom and the chelate backbone, thus providing a high-selectivity synthesis strategy for luminescent compounds. Since the energy barrier from B4 to BH3-pyrido[1,2-a]isoindole (D1) and pyrido[1,2-a]isoindole (A1) on the ground state is lower than that from B4 to 54-benzo[d]pyrido[2,1-f][1,2]azaborininr (C4), the retraction ring reaction is expected to proceed with larger probability than the H2 elimination upon heating. On the contrary, photoelimination of H2 may take place easily due to the almost barrierless pathway on the S1 state. Remarkably, we have located an energetically available conical intersection (S1/S0)X-1, which allows for ultrafast S1 → S0 decay and subsequently generation of C4. Our results not only throw light on the experimental observations of the selectivity of thermal elimination and photoelimination but also provide detailed information on the excited state as instructional implications for further synthesis and application of B,N-embedded aromatics.

The effect of Hyoscine butyl bromide on the duration and course of labor

Background: Cervical dystocia is caused by cervical spasm due to prolonged labor. Maternal complications can arise due to this such as intrapartum infection, pathological retraction ring (Bandls ring), maternal morbidity and it may also contribute to perinatal morbidity and mortality. Various spasmolytic drugs can help to relieve the cervical spasm and facilitate cervical dilatation during the first stage thereby decreasing the rate of cervical dystocia. Methods: This was a prospective study conducted in a tertiary center over a span of 1 year. 60 patients were randomly allotted in 2 groups. 1. 30 patients (15 primigravida and 15 multigravida) – control group 2. 30 patients (15 primigravida and 15 multigravida) – Injection Hyoscine butyl bromide (Buscopan) group. Injection Hyoscine butyl bromide 20 mg intramuscular was given at 3cm cervical dilatation. No further dose was given. A statistical test, ‘unpaired t test’, was used to test the results for statistical significance. A x2 (chi square) test was used to test results of side effects for statistical significance. Results: The duration of active first stage of labor was shorter in the Hyoscine butylbromide group (170.3 min) as compared to control group (216.7 min) in primigravida and multigravida (hyoscine butyl bromide group 120.9 min and control group 153.3 min). An unpaired t test showed p value of 0.011 in primigravida patients and p value of 0.003 in multigravida patients). No significant maternal and neonatal side effects were noted in the drug arm when compared to the control group (p value > 0.05). Conclusions: The rate of cervical dilatation under the influence of hyoscine butylbromide is significantly higher as compared to control group. The rate of dilatation is faster in multigravida patients as compared to primigravida. Hyoscine butylbromide is a safe drug with no fetal side effec

On rings whose modules have nonzero homomorphisms to nonzero submodules

We carry out a study of rings R for which HomR (M;N) 6= 0 for all nonzero N ≤ MR. Such rings are called retractable. For a retractable ring, Artinian condition and having Krull dimension are equivalent. Furthermore, a right Artinian ring in which prime ideals commute is precisely a right Noetherian retractable ring. Retractable rings are characterized in several ways. They form a class of rings that properly lies between the class of pseudo-Frobenius rings, and the class of max divisible rings for which the converse of Schur's lemma holds. For several types of rings, including commutative rings, retractability is equivalent to semi-Artinian condition. We show that a Kothe ring R is an Artinian principal ideal ring if and only if it is a certain retractable ring, and determine when R is retractable.

Water Absorption of Poly(methyl methacrylate) Measured by Vertical Interference Microscopy

PMMA (poly(methyl methacrylate)) is widely used to prepare orthopedic cements. They are in direct contact with cells and body fluids. PMMA, despite its hydrophobic nature, can absorb ~2% w/w water. We have evaluated by vertical interference microscopy if water absorption can produce a significant swelling in different types of PMMA blocks: pure, with a plasticizer, with a cross-linker, and in two types of commercial bone cements. Graphite rods which do not swell in water were used as internal standard. Hardness, indentation modulus, plastic, and elastic works were determined by nanoindentation under a 25mN fixed force. Vertical interference microscopy was used to image the polymer in the dry state and hydrated states (after 24 h in distilled water). On the surface of the polished polymers (before and after hydration), we measured roughness by the fractal dimension, the swelling in the vertical and the lateral directions. For each polymer block, four images were obtained and values were averaged. Comparison and standardization of the images in the dry and hydrated states were done with Matlab software. The average value measured on the graphite rod between the two images (dried and hydrated) was used for standardization of the images which were visualized in 3D. After grinding, a small retraction was noticeable between the surface of the rod and the polymers. A retraction ring was also visible around the graphite rod. After hydration, only the pure PMMA and bone cements had a significant swelling in the vertical direction. The presence of polymer beads in the cements limited the swelling in the lateral direction. Swelling parameters correlated with the nanoindentation data. PMMA can swell by absorbing a small amount of water and this induces a swelling that varies with the polymer composition and particle inclusions.

Sonographic appearance of a pathologic retraction ring

Sonographic appearance of a pathologic retraction ring

EXPERIMENTAL STUDIES OF INTESTINAL INTUSSUSCEPTION

For this experiment, paraffin induced phyma, shrunk phyma and artificial intussusception were produced at the terminal ileum of infant dogs .The development process of intestinal intussusception was traced in the dogs affected with the above types of phyma and macroscopic observation as well as record of action potential of smooth muscles, were made of the artificial intussusception to examine intestinal movements contributing to the progressive dynamics of intestinal canal intussusception. The experiment revealed the followings;1. Intestinal intussusception failed to develop from artificial phymas on the intestinal wall. This was because the intussusception did not create a stimulating factor to influence intestinal movements .2. Macroscopic observation of artificial intussusception revealed a characteristic increase of the retraction ring on the external canal of the intussuscepted portion, suggesting accentuation of external canal movements.Measurement of action potential of smooth muscles disclosed almost negative potential in the internal canal, and decrease in the proximal portion of intestinal canal. On the other hand, action potential of the external canal manifested an increase for a prolonged period, which showed that the external intestinal canal was contributing greatly to the progress of the intestinal intussusception.

Interlocked twins associated with retraction ring dystocia.

Interlocked twins associated with retraction ring dystocia.

Complications of the third stage of labor.

This paper includes management of the third stage of labor which should end with a critical period one hour after the delivery of the placenta. Placental delivery should exclude a radical, forcible and manual expression as a general policy, except in hemorrhage, and should be replaced by watchful waiting. Complications discussed are: postpartum hemorrhage, bleeding from cervical and vaginal lacerations, retained placental remnants, retention of placenta or retained placenta, placenta accreta, inversion of the uterus and retraction ring.

The functional anatomy of labor, with special reference to the human being

1.1. A structural, as well as a comparative anatomic and physiologic background, exists for the mode of travel of the wave of uterine contraction in the primate uterus.2.2. The evidence pertaining to the growth and unfolding or inclusion of the isthmus uteri into the general uterine cavity to form the so-called lower uterine segment may be summarized as follows: 2.1.a. Histologically the isthmus uteri increases from 2 to 3 times in length during the first three months of pregnancy and then unfolds and is included in the general uterine cavity. No evidence contrary to this observation in the human being could be found. Histologic and gross anatomic observations in the monkey lend substantial confirmation.2.2.b. The muscular fasciculi of the isthmus in pregnancy assume a more longitudinal or steeper course, but the architecture of the true cervix and corpus is not significantly modified. There is no contrary evidence; yet, one should like to have confirmation of Goerttler's observations.2.3.c. The membranes are relatively loosely attached to the lower segment and the mucosa of the lower segment differs histologically from that of the upper segment. This evidence is not substantial in that no definite line of demarcation between the two segments can be detected.2.4.d. The changes in the form of the uterus in pregnancy are compatible with and suggest that some event happens betweeen the third and fourth month of pregnancy which contributes (a) to a definite change in the breadth and thickness of the uterine cavity, (b) to a greater increase in vertical length in relation to the increase in the sagittal circumference of the cavity, and (c) to a rather sudden increase in the average distance of the lower edge of the placenta from the internal os (Table II).2.5.e. Using the “retraction ring” as the point of junction between the isthmus and corpus in late pregnancy and labor, it was found that the muscular fasciculi undergo approximately equal increases in longitudinal length in pregnancy. Or, it was found reasonable to conclude that an isthmus only 1 cm. long in the nongravid state may hypertrophy until it is 7 to 10 cm. in length at term.2.6.f. To obtain direct evidence, it would seem to be necessary to place some nonabsorbable material in the musculature at the site of the retraction ring in labor and then determine the site of the material in the fully involuted uterus.3.3. Data obtained from the mensuration of frozen sections of the human uterus have been analyzed in relation to the location and variability of the physiologic retraction ring and the position and dilatation of the cervical lip during labor.

CONSTRICTION RING DYSTOCIA

The clinical importance of intra-uterine rings complicating labor is not sufficiently appreciated. This condition, which causes dystocia, is chiefly functional and has been designated by at least twenty different terms. The assumption that intra-uterine rings are due solely to the contraction ring of Bandl, the contraction ring of Schroeder or the retraction ring of Barbour and Lusk is not tenable, in view of the different uterine levels at which they are found. The designation of this dystocia as a constriction ring dystocia is based on biologic grounds. A review of 350 cases collected from the literature and twenty-one cases in my experience demonstrates that a conservative management with delivery by vagina is the safest for the mother and child. THE FORMATION OF INTRA-UTERINE RINGS The physiologic division of the uterus into an upper and a lower uterine segment was definitely established by the second stage frozen section of Braune1

Constriction Ring Dystocia

The clinical importance of intra-uterine rings complicating labor is not sufficiently appreciated. This condition, which causes dystocia, is chiefly functional and has been designated by at least twenty different terms. The assumption that intra-uterine rings are due solely to the contraction ring of Bandl, the contraction ring of Schroeder or the retraction ring of Barbour and Lusk is not tenable, in view of the different uterine levels at which they are found. The designation of this dystocia as a constriction ring dystocia is based on biologic grounds. A review of 350 cases collected from the literature and twenty-one cases in my experience demonstrates that a conservative management with delivery by vagina is the safest for the mother and child. THE FORMATION OF INTRA-UTERINE RINGS The physiologic division of the uterus into an upper and a lower uterine segment was definitely established by the second stage frozen section of Braune1

The contraction as opposed to the retraction ring in labour

The contraction as opposed to the retraction ring in labour

The Retraction Ring as a Cause of Dystocia.

The Retraction Ring as a Cause of Dystocia.

The Retraction Ring as a Cause of Obstruction in Labour.

BJOG: An International Journal of Obstetrics & GynaecologyVolume 20, Issue 1 p. 11-17 The Retraction Ring as a Cause of Obstruction in Labour. Robert Jardine M.D., Robert Jardine M.D.Search for more papers by this author Robert Jardine M.D., Robert Jardine M.D.Search for more papers by this author First published: July 1911 https://doi.org/10.1111/j.1471-0528.1911.tb12839.xCitations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume20, Issue1July 1911Pages 11-17 RelatedInformation

A Case of Difficult Labour, with Observations on the Retraction Ring and on the Post‐Maturity of the Fœtus.

A Case of Difficult Labour, with Observations on the Retraction Ring and on the Post‐Maturity of the Fœtus.