Efficient preparation of enantiomerically pure (2S)-aziridine-2-carboxaldehyde 9 and its 2(R) isomer and highly diastereoselective addition of organolithium reagents to the aldehyde 9 are described. The diastereoselectivity in additions of the lithium reagents seems to come from "chelation-controlled" carbon-carbon bond formation and is influenced by the source of the organometallic compound, solvent, and the presence of a Li salt. The C(3)-N bond of the aziridine ring of the addition products was regioselectively reduced by catalytic hydrogenation in the presence of Pearlman's catalyst to provide enantiomerically pure 1,2-amino alcohols. The absolute stereochemistries of the amino alcohol 13a were assigned as (1S,2S) when the C-1 substituent was phenyl by comparison with those of commercially available norpseudoephedrine.

Chromium-based ethylene tetramerization catalyst precursors of the type {(DPPME)CrCl 2 ( μ-Cl)} 2 with a chiraphos ligand backbone [DPPME = {Ar(R 1 R 2 )} 2 PCH(CH 3 )CH(CH 3 )P{Ar(R 1 R 2 )} 2 ] were prepared and characterized, in which substituents on the aryl phosphine varied with electron-donating and -withdrawing groups (

A 38-year-old male was admitted with symptoms of upper respiratory infection. Despite medical treatment, his symptoms of dyspnea and anxiety became aggravated, and bilateral lung infiltration was noted on radiological imaging studies. His hypoxemia failed to improve even after the application of endotracheal intubation with mechanical ventilator care, and we therefore decided to initiate venovenous extracorporeal membrane oxygenation (VV ECMO) for additional pulmonary support. On his twentieth day of hospitalization, hypotension and desaturation (arterial saturated oxygen <85%) developed, and right ventricular failure was confirmed by two-dimensional echocardiography. Therefore, we changed from VV ECMO to venoarteriovenous (VAV) ECMO, and the patient ultimately recovered. In this case, right ventricular dysfunction and volume overloading were induced by long-term VV ECMO therapy, and we successfully treated these conditions by changing to VAV ECMO.

A striking multiple-step behavior has been observed in magnetoresistance measurements during magnetization reversal in anti-ferromagnetically coupled GaMnAs/GaAs:Be multilayers. This behavior arises from the splitting of the energy degeneracy of spin configurations established by nearest-neighbor interlayer exchange coupling (NN IEC) with contribution from the next-nearestneighbor (NNN) IEC. This observation reveals that NNN IEC plays a crucial role in the magnetic behavior of these multilayer structures.

OBJECTIVE To compare the reliability of the Patient and Observer Scar Assessment Scale (POSAS) with the Vancouver Scar Scale (VSS) in evaluating thyroidectomy scars. METHODS At 6 months after the operation, 112 patients who underwent thyroid surgery via collar neck incision were evaluated by two blinded plastic surgeons and two senior residents using the VSS and the observer component of the POSAS. In addition, the observer-reported VAS score and patient-reported Likert score were evaluated. Internal consistency, interobserver reliability, and correlations between the patient- and observer-reported outcomes were examined. RESULTS The observer component of POSAS scores demonstrated higher internal consistency and interobserver reliability than the VSS. However, the correlations between the observer-reported VAS score and the patient-reported Likert score (0.450) and between the total sum of patient and observer component scores (0.551) were low to moderate. CONCLUSIONS The POSAS is more consistent over repeated measurements; accordingly, it may be considered a more objective and reliable scar assessment tool than the VSS. However, a clinician’s perspective may not exactly match the patient’s perception of the same scar.