1,721,153 research outputs found
A comparative study on falling weight impact properties of jute/epoxy and hemp/epoxy laminates
No full textOne of the principal reasons for limited use of plant fibre composites is their sensitivity to impact loading and the difficulty in characterising and assessing the criticality of impact damage. In this study, a comparison between two composite architectures has been carried out, namely a hemp/epoxy random mat and a jute/epoxy plain weave laminate, both with 45±2% vol. of reinforcement fibres. Work carried out concentrated on comparing and discussing the falling weight impact performance of the two laminates with different fibre architecture, by studying their impact hysteresis cycles and investigating their respective modes of damage. This was done in view of a possible application of a hybrid of the two laminates for impact resistance purposes. The results allowed quantifying the superiority of hemp/epoxy on jute/epoxy laminates under falling impact loading: however, the latter laminates appear to show more consistent impact properties and a more predictable mode of damage, which was attributed to an improved a better fibre-matrix impregnation
The clinical usefulness of preoperative intratumoral doppler analysis in predicting lymph node metastasis in patients with endometrial carcinoma
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Unraveling the hydration properties of the Ba2+ aqua ion: the interplay of quantum mechanics, molecular dynamics, and EXAFS spectroscopy
No full textThe structural and dynamic properties of the Ba2+ cation in water have been studied by combining quantum mechanical (QM) calculations, molecular dynamics (MD) simulations, and extended X-ray absorption fine structure (EXAFS) spectroscopy. An effective Ba2+-water interaction potential, to be used in the MD simulation of a Ba2+ aqueous solution, has been developed by means of QM methods, and the validity of the whole procedure has been assessed by comparing the theoretical structural results with the EXAFS experimental data. By combining distance and angular distribution functions it was possible to unambiguously identify the geometry adopted by the water molecules surrounding the ion in the solution. The Ba2+ ion was found to preferentially form an 8-fold first shell complex with a bicapped trigonal prism (BTP) geometry. The 8-fold complex is in equilibrium with a 9-fold structure having a tricapped trigonal prism (TTP) geometry, and the hydration shell is very diffuse and flexible, being characterized by a very fast solvent exchange process on the picosecond time scale
Therapy and prevention of obstetric hemorrhage by tamponade using a balloon catheter
No full textThe aim of this study was to verify the possibility to use a balloon catheter as hemostatic method in pregnancies at high risk for hemorrhage as an alternative to less conservative surgical procedures. In 4 pregnancies at risk for hemorrhage, a compressive endouterine or endocervical method, consisting of a balloon catheter filled of warm saline solution, was used in order to stop or to prevent otherwise uncontrollable bleeding. In the cases treated the use of the balloon catheter was safe and effective both in the treatment of hemorrhage due to abnormal placentation and in the prevention of hemorrhagic complications due to abnormal implantation of pregnancy. Among novel medical and surgical approaches developed to control obstetric hemorrhage, tamponade using a balloon catheter could be considered a valid option. Moreover, this procedure, by avoiding radical surgical treatments, such as hysterectomy, which are frequently performed in unstable patients, could offer the advantage of preserving fertility
Antiphospholipid antibodies regulate the expression of trophoblast cell adhesion molecules
Full text linkObjective: To examine the effect of antiphospholipid antibodies on trophoblast expression of adhesion
molecules.
Design: Primary cytotrophoblast cell cultures.
Setting: Department of Obstetrics and Gynecology, Catholic University, Rome, Italy.
Patient(s): Five normal pregnant women underwent uncomplicated vaginal delivery at 36 weeks of gestation.
Intervention(s): IgG antibodies were isolated from a patient with antiphospholipid syndrome and from a
normal control subject, using protein-G Sepharose columns. Cytotrophoblast cells were dispersed in bicarbonate
buffer containing trypsin and DNAse I.
Main Outcome Measure(s): We investigated the effects of antiphospholipid antibodies on trophoblast
adhesion molecules (1 and 5 integrins, E and VE cadherins), both at the protein and mRNA levels.
Result(s): The 1 and 5 integrins were present in trophoblast cells from 24 hours of culture. Treatment with
IgG that were obtained from the patient with antiphospholipid syndrome significantly decreased 1 integrin
and increased 5 integrin at both the mRNA and protein levels. Furthermore, IgG with antiphospholipid
antibodies activities induced VE-cadherin down-regulation and the E-cadherin up-regulation at protein and
mRNA levels compared with control IgG or untreated cells.
Conclusion(s): The results suggest that the inadequate trophoblastic invasion, induced by antiphospholipid
antibodies, can be the result of abnormal trophoblast adhesion molecules expression
Effect of celioscopic ovarian resection in patients with polycystic ovaries
No full textOvarian resection was performed by means of celioscopy in 12 patients with polycystic ovaries (PCO), who had not responded to clomiphene + HCG therapy. This therapy had induced ovulation in only 14% of 56 therapeutic cycles. Ovarian resection through celioscopy induced ovulation in 45% of cycles. Clomiphene + HCG therapy after resection in patients with no spontaneous ovulation induced ovulation in 44% of cycles. Seven pregnancies followed in 5 women, equal to 41% of patients. Hormonal patterns (FSH, LH, E2, progesterone, dehydroepiandrosterone sulfate, testosterone) before and after resection showed no significant variation. The authors emphasize other advantages of this technique, such as fewer surgical injuries than laparotomy, relative harmlessness of the treatment, the possibility of repeating it and of performing subsequent laparotomy
Monoclonal anti-annexin V antibody inhibits trophoblast gonadotrophin secretion and induces syncytiotrophoblast apoptosis
Full text linkThe pathogenic role of anti-annexin V antibodies remains unclear. Anti-annexin V antibodies are frequently associated with higher incidences of intrauterine fetal loss, preeclampsia, and arterial and venous thrombosis. The present study investigated the in vitro ability of anti-annexin V antibody to bind human trophoblast cells, to affect trophoblast gonadotropin secretion and invasiveness, and to induce placental apoptosis. Cytotrophoblast cells were dispersed in Ringer bicarbonate buffer containing trypsin and DNase I, filtered, and layered over a Percoll gradient in Hanks balanced salt solution. In the case of monoclonal anti-annexin V antibody, the highest binding was found when the cells displayed the greatest amount of syncytium formation. Anti-annexin V antibody, but not its negative control, induced trophoblast apoptosis and significantly reduced trophoblast gonadotropin secretion. These findings suggest that recognition by anti-annexin V antibody of adhered annexin V on trophoblast cell structures might represent a potential pathogenic mechanism by which these antibodies can cause defective placentatio
Retrograde ejaculation: a more convenient method for artificial insemination
No full textA case of retrograde ejaculation not responding to medical treatment is described in which the problem of sterility was overcome by artificial insemination. The semen was collected from urine after coitus by previous alkalinization with 1.63 g NaHCO3 once daily. Pregnancy occurred at the 4th insemination during the 1st treatment cycle. This technique seems to be the most suitable for artificial insemination in cases of retrograde ejaculation
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