Protracted course of coronavirus disease with severe acute respiratory distress syndrome: a case report

Background

Coronavirus disease (COVID‐19) is a growing concern worldwide. Approximately 5% of COVID‐19 cases require intensive care. However, the optimal treatment for respiratory failure in COVID‐19 patients is yet to be determined.

Case presentation

A 79‐year‐old man with severe acute respiratory distress syndrome due to COVID‐19 was admitted to our intensive care unit. Prone ventilation was effective in treating the patient’s hypoxemia. Furthermore, the patient received lung protective ventilation with a tidal volume of 6–8 mg/kg (predicted body weight). However, the patient’s respiratory failure did not improve and he died 16 days after admission because of multiple organ failure. Serial chest computed tomography revealed a change from ground‐glass opacity to consolidation pattern in both lungs.

Conclusions

We report a protracted case of COVID‐19 in a critically ill patient in Japan. Although prone ventilation could contribute to treating hypoxemia, its efficacy in preventing mortality from COVID‐19 is unknown.

Staged hybrid aortic procedure for chronic type B aortic dissection in two patients with Marfan syndrome

We here report two patients with Marfan syndrome treated by a combination of surgical grafting and endovascular repair in our hospital. One was a 32-year-old woman who underwent thoracoabdominal aortic replacement for a Crawford type III dissected aortic aneurysm. Subsequently, the Bentall procedure and total arch replacement was performed for an aortic root and arch aneurysm. Finally, thoracic endovascular aortic repair bridging implanted grafts was performed. The second was a 67-year-old woman with Stanford type A acute aortic dissection who underwent the Bentall procedure and total arch replacement at the age of 64. Subsequently, she underwent thoracoabdominal replacement for a dilated dissected aortic aneurysm and finally, bridging endovascular aortic repair was performed. This procedure is less invasive than open repair for patients with Marfan syndrome.

[Early Postoperative Hemodynamics of Mitral Valvuloplasty Using Colvin-Galloway Future Band]

The Colvin-Galloway( CG) Future annuloplasty band is a new semirigid partial band, which was introduced in 2012 in Japan. A total of 60 consecutive patients who underwent mitral valve repair with the CG Future Band were assessed by echocardiography in terms of residual mitral regurgitation and diastolic mitral function postoperatively. Intraoperative 3-dimensional echocardiography beautifully demonstrated the physiological change of the aortic curtain during the cardiac cycle. 30 mm was used in 18 patients, 32 mm in 17, 28 mm in 15, 34 mm in 5, 36 mm in 2, and 26 mm in 2. There were 2 patients with mild residual mitral regurgitation and 58 patients with less than mild. The mean gradient of diastolic mitral pressure gradient was 2.8±1.3 mmHg. Early results of mitral valve repair with a CG Future Band were acceptable in terms of residual mitral regurgitation and diastolic mitral function after repair.

Crystal structure and thermoelectric properties of Sr-Mo substituted CaMnO3: a combined experimental and computational study

A combination of experimental and computational techniques has been employed to study doping effects in perovskite CaMnO₃. High quality Sr-Mo co-substituted CaMnO₃ ceramics were prepared by the conventional mixed oxide route. Crystallographic data from X-ray and electron diffraction showed an orthorhombic to tetragonal symmetry change on increasing the Sr content, suggesting that Sr widens the transition temperature in CaMnO₃ preventing phase transformation-cracking on cooling after sintering, enabling the fabrication of high density ceramics. Atomically resolved imaging and analysis showed a random distribution of Sr in the A-site of the perovskite structure and revealed a boundary structure of 90° rotational twin boundaries across {101}_orthorhombic; the latter are predominant phonon scattering sources to lower the thermal conductivity as suggested by molecular dynamics calculations. The effect of doping on the thermoelectric properties was evaluated. Increasing Sr substitution reduces the Seebeck coefficient but the power factor remains high due to improved densification by Sr substitution. Mo doping generates additional charge carriers due to the presence of Mn³⁺ in the Mn⁴⁺ matrix, reducing electrical resistivity. The major impact of Sr on thermoelectric behaviour is the reduction of the thermal conductivity as shown experimentally and by modelling. Strontium containing ceramics showed thermoelectric figure of merit (ZT) values higher than 0.1 at temperatures above 850 K. Ca_0.7Sr_0.3Mn_0.96Mo_0.04O₃ ceramics exhibit enhanced properties with S_1000K = -180 μV K^-1, ρ_1000K = 5 × 10^-5 Ωm, k_1000K = 1.8 W m^-1 K^-1 and ZT ≈ 0.11 at 1000 K.

Thermoelectric properties of Ni-based oxides

A high-throughput screening technique has been developed and was utilized in the discovery of a new n-type oxide possessing good thermoelectric properties. Screening of metal binary systems consisting of 3d transition metals using this technique showed LaNiO3 to possess the desired n-type properties. Electrical resistivity (ρ) of this oxide is favorably quite low, however, the Seebeck coefficient (S) is as small as –25 μV/K. To enhance the thermoelectric properties of LaNiO3, high-throughput screening was employed to examine candidates from the metal ternary La1–xMxNiO3 and LaNi1–xNxO3 systems. Bi substitution in the La1–xMxNiO3 systems and Cu substitution in the LaNi1–xNxO3 systems were found to be effective for improvement of S and ρ respectively.

Superspace crystal symmetry of thermoelectric misfit cobalt oxides and predicted structural models

Single crystals of thermoelectric misfit lamellar cobalt oxide phases in the Bi–Ca–Co–O and I–Bi–Ca–Co–O systems were synthesized. They are characterized by aperiodic structures involving two partially independent sublattices: a CdI2-type pseudohexagonal CoO2 layer and a rocksalt-type BiCaO2 slab allowing the intercalation of iodine. The crystal symmetry of these structures is discussed using the four-dimensional superspace formalism. The superspace Laue classes of the iodine-free and the intercalated compounds are P2/m(0δ½) (a 1 = 4.901, b 1 = 4.730, b 2 = 2.80, c 1 = 14.66 Å, β = 93.49°) and A2/m(0δ1) (a_1^{\prime} = 4.903, b_1^{\prime} = 4.742, c_1^{\prime} = 36.51 Å, β = 87.30°), respectively. A comparison is given with the related Bi–Sr–Co–O misfit compounds. The present structures are compatible with the presence of an intrinsic modulation with a wavelength matching the misfit aperiodicity in the b direction. Preliminary partial structure refinements confirm the layer stacking of the structure and the intercalation of I between the Bi—O layers for the second phase. A comparison with other cobalt oxide phases, as well as symmetry and metric considerations allow us to predict average structures for these new phases and to describe the common structural features assumed for all these lamellar misfit cobalt oxides.

Nanoblock Coupling Effect in Iodine Intercalated [Bi0.82CaO2]2[CoO2]1.69 Layered Cobaltite

We report on the structural, microstructural, and electronic properties of iodine intercalated [Bi0.82CaO2]2[CoO2]1.69 misfit cobaltite. We first prove through a detailed and careful structural study that the block layer structure can be modified in the desired way. Iodine enters the material between the [BiO] double layers, and the c-cell parameter of the pristine compound is elongated by 3.6 Angstrom. On the basis of this result, we point out the coupling between the block-layer structure and the transport properties. Additionally, we provide in-depth commentary and discussion of some extra results, clarifying some doping effects in the quasi-2D studied phase. Finally, we also propose some expressions that might be useful to material scientists for the tuning of the properties of such compounds.