428 research outputs found
Regio- and stereoselective lithiation of 2,3-diphenylaziridines: A multinuclear NMR investigation
No full text(Figure Presented) The α-lithiation-trapping sequence of trans-N-alkyl-2,3-diphenylaziridines (s-BuLi or s-BuLi/TMEDA), taking place with a stereochemistry which dramatically depends on the solvent coordinating ability (inversion of configuration in THF and retention in toluene), has been carefully investigated. 1H,13C, and 7Li multinuclear NMR investigations at low temperature suggest that two differently configured lithiated aziridines (monomeric cis-1-Li in THF and dimeric trans-1-Li in toluene) are involved. © 2008 American Chemical Society
Regio- and Stereoselective Lithiation of 2,3- Diphenylaziridines: A Multinuclear NMR Investigation
No full textThe R-lithiation-trapping sequence of trans-N-alkyl-2,3-diphenylaziridines (s-BuLi or s-BuLi/TMEDA),
taking place with a stereochemistry which dramatically depends on the solvent coordinating ability (inversion of configuration in THF and retention in toluene), has been carefully investigated. 1H,13C, and 7Li multinuclear NMR investigations at low temperature suggest that two differently configured lithiated aziridines (monomeric is-1-Li in THF and dimeric trans-1-Li in toluene) are involved
Michael Addition of Chloroalkyloxazolines to Electron poor Alkenes: Synthesis of Heterosubstituted Cyclopropanes
No full textLithiated 2-(1-chloroethyl)-4,4-dimethyl-2-oxazoline 7 adds to electron-poor alkenyl heterocycles to afford substituted cyclopropanes in excellent yields. A route to chiral nonracemic heterosubstituted cyclopropanes, starting from optically active 2-chloromethyl-2-oxazolines, is highlighted as well
An open-label, multicentre trial to evaluate the vaginal bleeding pattern of the combined contraceptive vaginal ring NuvaRing
No full textObjective: The objective of this multicentre, non-controlled, open-label study is the evaluation of the bleeding patterns during the use of a vaginal combined contraceptive, its safety in relation to occurrence of adverse effects, its efficacy as a contraceptive method and user compliance. Study design: Healthy female volunteers (N = 165), asking for contraception, were enrolled to participate in the study. Each subject was given seven vaginal rings, releasing an average amount of 120 μg etonogestrel (ENG) and 15 μg ethinylestradiol (EE) per day. Study period was 7 cycles. A total of 878 cycles was valid for statistical analysis. The primary parameter, (breakthrough bleeding and/or spotting), was recorded for each cycle. The subjects were asked to report any adverse effect experienced during the treatment period, general physical and gynaecological examinations were performed and haematological blood tests were taken. Results: Breakthrough bleeding/spotting occurred in 5.01% cycles (44 out of 878 cycles, of whom 37 were breakthrough spotting only). Absence of withdrawal bleeding during the ring-free period was reported in 1.94% cycles (17 out of 878). Forty-one subjects (24.8%) reported 66 events that were potentially drug-related. The most frequently drug-related events were weight increase (10 cases), headache (9 cases), nausea (4 cases). No pregnancy was reported during the study period. Haematology and chemical chemistry tests showed no clinically significant abnormality. Conclusions: In the present study, NuvaRing ® has shown to be a valid contraceptive method to ensure optimal cycle control with low incidence of irregular bleeding and altered withdrawal bleeding. The low incidence of gastrointestinal side effects (nausea, vomiting) may be related the low hormonal dose and to the vaginal delivery of hormones which avoids the gastrointestinal tract. © 2008 Elsevier Ireland Ltd. All rights reserved
Endometriosis in Italy: From cost estimates to new medical treatment
No full textEndometriosis is defined as the presence of endometrial-like tissue outside the uterus, which induced a chronic inflammatory reaction. The data collected from Italy showed that around 3 million women are affected by endoemtriosis and the condition was predominantly found in women of reproductive age (50% of women were in the 29-39 age range), only 25% of women were asymptomatic. The associated symptoms can create an impact in general physical, mental, and social well-being. Endometriosis is associated with severe dysmenorrhea, deep dyspareunia, chronic pelvic pain, ovulation pain, cyclical, or perimenstrual symptoms, with or without abnormal bleeding, infertility, and chronic fatigue. The annual cost for hospital admission can be estimated to be in a total around 54 million euros. The average time for right diagnosis is around 9 years still today and it follows a long and expensive diagnostic search. Therapies can be useful to relieve and sometimes solve the symptoms, encourage fertility, eliminate endometrial lesions, and restore the anatomy of the pelvis. For medical therapy, several different preparations (oral contraceptives, progestogenics, gestrinone, danazol, and GnRHa) and new options (GnRH antagonists, aromatase inhibitors, estrogen receptor beta agoinist, progesterone receptor modulators, angiogenesis inhibitors, and COX-2 selective inhibitors) are available.Endometriosis is defined as the presence of endometrial-like tissue outside the uterus, which induced a chronic inflammatory reaction. The data collected from Italy showed that around 3 million women are affected by endoemtriosis and the condition was predominantly found in women of reproductive age (50% of women were in the 29-39 age range), only 25% of women were asymptomatic. The associated symptoms can create an impact in general physical, mental, and social well-being. Endometriosis is associated with severe dysmenorrhea, deep dyspareunia, chronic pelvic pain, ovulation pain, cyclical, or perimenstrual symptoms, with or without abnormal bleeding, infertility, and chronic fatigue. The annual cost for hospital admission can be estimated to be in a total around 54 million euros. The average time for right diagnosis is around 9 years still today and it follows a long and expensive diagnostic search. Therapies can be useful to relieve and sometimes solve the symptoms, encourage fertility, eliminate endometrial lesions, and restore the anatomy of the pelvis. For medical therapy, several different preparations (oral contraceptives, progestogenics, gestrinone, danazol, and GnRHa) and new options (GnRH antagonists, aromatase inhibitors, estrogen receptor beta agoinist, progesterone receptor modulators, angiogenesis inhibitors, and COX-2 selective inhibitors) are available
Stereoselective Synthesis of 4,5-Epoxy-1,2-Oxazin-6-ones via Reaction of beta-Lithiated Oxazolinyloxiranes with Nitrones
No full textAnatomic substrates for, and function of, the functionally univentricular circulation before and after surgical procedures
No full textRegio- and stereoselective lithiation and electrophilic substitution reactions of N-alkyl-2,3-diphenylaziridines: Solvent effect
No full textThe lithiation reaction of cis- and trans-N-alkyl-2,3-diphenylaziridines has been investigated. While cis-diphenylaziridines do not undergo any lithiation upon treatment with organolithiums, the lithiation reaction of the trans counterparts is completely α-regioselective and the stereochemical course of the lithiation-trapping sequence is solvent dependent: inversion of configuration in coordinating solvents (THF or toluene/crown ether) and retention in hexane, ether, or toluene. The preparation of stereodefined functionalized N-alkyl-2,3-diphenylaziridines is described. © 2007 American Chemical Society
Hormone-dependent gynaecological disorders: a pathophysiological perspective for appropriate treatment
No full textEngine displacement modularity for enhancing automotive s.i. engines efficiency at part load
No full textCylinder deactivation is a well-known and effective technology to improve spark ignition engines’ efficiency at part load, thanks to its capability of significantly reducing pumping losses, by switching off a fraction of the cylinders at part load, while operating the active cylinders at higher loads and therefore with higher efficiencies. This technology can be utilized as an alternative to, or in combination with, other efficiency improving measures such as engine downsizing and Variable Valve Actuation (VVA). It is worth mentioning however that the implementation of a cylinder deactivation strategy generally requires intake and exhaust valve deactivation in deactivated cylinders, so to minimize pumping losses thanks to the “gas spring” behavior of the trapped charge.
In this paper the effects and possible benefits of cylinder deactivation on a four cylinder turbocharged downsized gasoline engine equipped with MultiAir VVA system were experimentally investigated, aiming to obtain further reductions of pumping losses beyond those achievable through normally adopted Early Intake Valve Closure (EIVC) strategies. Moreover, since the MultiAir VVA system does not allow exhaust valve deactivation, an innovative strategy was developed, exploiting internal Exhaust Gas Recirculation (iEGR) in the inactive cylinders in order to minimize their pumping losses.
This innovative cylinder deactivation technique was demonstrated to be effective in the low speed and low load operating region of the engine map, leading to an impressive 30% reduction of pumping losses compared to the EIVC unthrottled load control
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