The vinyliminium complexes Fe2{μ-η1:η3-Cγ(R‘)CβHCαNMe2}(μ-CO)(CO)(Cp)2SO3CF3 (R‘ = Tol, 2a; SiMe3, 2b; Me, 2c; CH2OH, 2d) undergo hydride addition at the iminium carbon (Cα), upon treatment with ...NaBH4, affording the corresponding μ-vinylalkylidene complexes Fe2{μ-η1:η3-C(R‘)CHCHNMe2}(μ-CO)(CO)(Cp)2 (R‘ = Tol, 5a; SiMe3, 5b; Me, 5c; CH2OH, 5d). Similarly, the complexes Fe2{μ-η1:η3-Cγ(R‘)CβHCαN(Me)(CH2Ph)}(μ-CO)(CO)(Cp)2SO3CF3 (R‘ = Tol, 4a; SiMe3, 4b; COOMe, 4c) react with NaBH4 at the Cα, yielding Fe2{μ-η1:η3-Cγ(R‘)CβHCα(H)N(Me)(CH2Ph)}(μ-CO)(CO)(Cp)2 (R‘ = Tol, 7a; SiMe3, 7b; COOMe, 7c). By contrast, the reactions of NaBH4 with Fe2{μ-η1:η3-Cγ(R‘)CβHCαN(Me)(Xyl)}(μ-CO)(CO)(Cp)2 (R‘ = Tol, 3a; SiMe3, 3b; Me, 3c; CH2OH, 3d; Ph, 3e; COOMe, 3f; Bun, 3g; H, 3h), in which the substituent at the iminium nitrogen is the more sterically hindered Xyl group (Xyl = 2,6-Me2C6H3), lead to the formation of the bis-alkylidene complexes Fe2{μ-η1:η2-C(R‘)CH2CN(Me)(Xyl)}(μ-CO)(CO)(Cp)2 (R‘ = Tol, 6a; SiMe3, 6b; Me, 6c; CH2OH, 6d; Ph, 6e; COOMe, 6f; Bun, 6g; H, 6h). Compounds 6a−h result from regioselective hydride addition at the Cβ, presumably because of the steric protection exerted by the Xyl group on the Cα carbon. All the new compounds have been investigated by IR and NMR spectroscopy, and the molecular structures of complexes 5a and 6f have been elucidated by X-ray diffraction studies. LiHBEt3 selectively attacks the Cα carbon, despite the presence of the Xyl substituent; therefore Fe2{μ-η1:η3-Cγ(R‘)CβHCαN(Me)(Xyl)}(μ-CO)(CO)(Cp)2SO3CF3 (R‘ = Me, 3c; COOMe, 3f) are converted into the corresponding μ-vinylalkylidene complexes Fe2{μ-η1:η3-C(R‘)CHCHN(Me)(Xyl)}(μ-CO)(CO)(Cp)2 (R‘ = Me, 8a; COOMe, 8b).
Abstract Background and purpose Irradiation of the Pharyngeal Superior Constrictor Muscle (PSCM) seems to play a crucial role in radiation-related swallowing dysfunctions. Purpose of our study was to ...quantify operator-related variability in the contouring of PSCM on Computed Tomography (CT) scans and adherence with contours derived from MR images. Materials and methods Three sets of treatment planning CT and their corresponding MR images were selected. Contouring of the PSCM was performed using both a literature-based method, derived from literature review, and an optimized method, derived from Magnetic Resonance (MR) images thus obtaining “literature-based” and “optimized” contours. Each operator contoured the PSCM on CT scans according to both methods for three times in three different days. Inter- and intra-operator variability and adherence to a contour obtained from MR images (named “MR-derived” contour) were analyzed. Results Thirty-four operators participated and 612 contours were obtained. Both intra- and inter-operator variability and adherence to the “MR-derived” contour were significantly different between the two methods ( p ⩽ 0.05). The “optimized” method showed a lower intra- and inter-operator variability and a higher adherence to the “MR-derived” contour. Conclusions The “optimized” method ameliorates both operator-related variability and adherence with MR images.
Alkynes (R
′CCR
″) insert into the μ-carbon–metal bond of diiron complexes affording μ-σ:η
3 vinyliminium species. Several isomers have been found arising from: (i) the iminium moiety configuration ...(
E,
Z), (ii) mutual Cp position (
cis–
trans isomers), (iii) head–head or head–tail insertion mode of R
′CCR
″. These isomeric forms have been investigated by NMR and X-ray diffraction.
Terminal alkynes (HCCR
′) (R
′=COOMe, CH
2OH) insert into the metal–carbyne bond of the diiron complexes Fe
2{μ-CN(Me)(R)}(μ-CO)(CO)(NCMe)(Cp)
2SO
3CF
3 (R=Xyl,
1a; CH
2Ph,
1b; Me,
1c; Xyl=2,6-Me
2C
6H
3), affording the corresponding μ-vinyliminium complexes Fe
2{μ-σ:η
3-C(R
′)CHCN(Me)(R)}(μ-CO)(CO)(Cp)
2SO
3CF
3 (R=Xyl, R
′=COOMe,
2; R=CH
2Ph, R
′=COOMe,
3; R=Me, R
′=COOMe,
4; R=Xyl, R
′=CH
2OH,
5; R=Me, R
′=CH
2OH,
6). The insertion is regiospecific and C–C bond formation selectively occurs between the carbyne carbon and the CH moiety of the alkyne. Disubstituted alkynes (R
′CCR
′) also insert into the metal–carbyne bond leading to the formation of Fe
2{μ-σ:η
3-C(R
′)C(R
′)CN(Me)(R)}(μ-CO)(CO)(Cp)
2SO
3CF
3 (R
′=Me, R=Xyl,
8; R
′=Et, R=Xyl,
9; R
′=COOMe, R=Xyl,
10; R
′=COOMe, R=CH
2Ph,
11; R
′=COOMe, R=Me,
12). Complexes
2,
3,
5,
8,
9 and
11, in which the iminium nitrogen is unsymmetrically substituted, give rise to
E and/or
Z isomers. When iminium substituents are Me and Xyl, the NMR and structural investigations (X-ray structure analysis of
2 and
8) indicate that complexes obtained from terminal alkynes preferentially adopt the
E configuration, whereas those derived from internal alkynes are exclusively
Z. In complexes
8 and
9,
trans and
cis isomers have been observed, by NMR spectroscopy, and the structures of
trans-
8 and
cis-
8 have been determined by X-ray diffraction studies.
Trans to
cis isomerization occurs upon heating in THF at reflux temperature. In contrast to the case of HCCR
′, the insertion of 2-hexyne is not regiospecific: both Fe
2{μ-σ:η
3-C(CH
2CH
2CH
3)C(Me)CN(Me)(R)}(μ-CO)(CO)(Cp)
2SO
3CF
3 (R=Xyl,
13; R=Me,
15) and Fe
2{μ-σ:η
3-C(Me)C(CH
2CH
2CH
3)CN(Me)(R)}(μ-CO)(CO)(Cp)
2SO
3CF
3 (R=Xyl,
14, R=Me,
16) are obtained and these compounds are present in solution as a mixture of
cis and
trans isomers, with predominance of the former.
The implantable gastric stimulator (IGS), a pacemaker-like device, has been found to be safe and effective to induce and maintain weight loss. We present our experience with 20 morbidly obese ...patients.
Between September 20 and November 22, 2002, 20 patients (F/M 12/8), mean age 40.3 years (23-62) underwent IGS implantation. Mean BMI was 40.9 (33.9-48.2), mean weight 115.0 kg (87.0-137.0) and mean excess weight (EW) 51.3 kg (35.6-70.1).Co-morbitidies were: 3 cases of hypertension, 1 diabetes, 1 dislipidemia and 1 depression. Mean operative time was 58.5 min (37-85). The IGS was actived 30 days after implantation. Patients were advised to follow a low calorie diet and behavior modification (to avoid fat and to ingest more liquids during meals, to chew slowly, to eat vegetables before main meals, and to perform exercise daily).
Mean +/- standard error percent excess weight loss (%EWL) was: 10.6+/-1.8 at 1 month; 15.0+/-2.3 at 2 months; 16.6+/-2.6 at 3 months; 18.1+/-3.5 at 4 months; 15.5+/-3.5 at 6 months; 18.9+/-3.5 at 8 months; and 23.8+/-5.0 at 10 months. There were no intra-operative surgical or long-term complications. There were 3 intra-operative gastric penetrations, observed by gastroscopy, without sequelae. One patient with hypertension ceased his medical therapy at the 4th month.
IGS can be implanted laparoscopically with minimal perioperative complications. The observed weight loss is comparable to other noninvasive procedures. If weight loss is maintained, IGS could be considered as a first choice therapy in the treatment of morbid obesity in selected patients.
In this paper, we investigate the problem of the strategic foundation of the Cournot–Walras equilibrium approach. To this end, we respecify à la Cournot–Walras the mixed version of a model of ...simultaneous, noncooperative exchange, originally proposed by Lloyd S. Shapley. We show, through an example, that the set of the Cournot–Walras equilibrium allocations of this respecification does not coincide with the set of the Cournot–Nash equilibrium allocations of the mixed version of the original Shapley’s model. As the nonequivalence, in a one-stage setting, can be explained by the intrinsic two-stage nature of the Cournot–Walras equilibrium concept, we are led to consider a further reformulation of the Shapley’s model as a two-stage game, where the atoms move in the first stage and the atomless sector moves in the second stage. Our main result shows that the set of the Cournot–Walras equilibrium allocations coincides with a specific set of subgame perfect equilibrium allocations of this two-stage game, which we call the set of the Pseudo–Markov perfect equilibrium allocations.
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