Nanoengineered wood provides a renewable structural material with 3D micro and nanoarchitectures, exhibiting many beneficial characteristics such as being lightweight in nature, mechanically strong, eco‐friendly, thermally insulation, and low carbon footprint. Most nanocellulose aerogels lack sufficient mechanical strength, while nanowood involves a trade‐off between mechanical strength and insulation performance. Here, a nanowood‐derived product with mechanical/thermomechanical multistability called a wooden metamaterial, which is ultrastiff yet lightweight, is designed and synthesized. The self‐healing behaviors of cellulose nanofibrils originally present in the cell walls and their combination with microscale mechanical constraints are utilized to form directional porous frameworks (porosity ≥98%) and encapsulated empty fiber lumen in predesigned macroscopic architectures. The wooden metamaterials are lightweight, showing ultrahigh specific strength (207.7 MPa cm3 g−1), and ultrahigh anisotropy with an approximate factor of 4. Wooden metamaterials have overcome the mechanical/thermomechanical deficiencies of existing building materials and advanced aerospace thermal insulators, and have great potential for revolutionizing architecture and manufacturing industries, particularly as a lightweight, eco‐friendly, scalable, energy‐efficient, and cost‐effective.
Coronary artery–left ventricular multiple microfistulas (CALVMMFs) are a very rare type of coronary artery fistula. Because of their special anatomical structure and hemodynamics, CALVMMFs often result in no obvious symptoms and signs. Most patients are diagnosed by coronary angiography; however, as a routine noninvasive screening method, Doppler echocardiography is a potential first-choice diagnostic technique for patients with CALVMMFs. Although satisfactory results of CALVMMF closure are difficult to achieve, the clinical symptoms of these patients are not obvious, and drug therapy has a clear therapeutic effect on most patients. We herein introduce seven cases of CALVMMFs confirmed by our hospital and briefly review the related literature.
Dextrocardia is a congenital abnormal position of the heart in which the main part of the heart is in the right chest, and the long axis of the heart points to the lower right. Cases of a combination of dextrocardia and sick sinus syndrome are rare. A 65-year-old female patient was admitted to hospital with palpitations and dizziness for 1 week. Mirror-image dextrocardia and sick sinus syndrome were diagnosed by an electrocardiogram, echocardiography, Holter monitoring, and X-rays. Finally, we successfully implanted a dual-chamber pacemaker into the patient. The patient had an uneventful recovery and was discharged when her symptoms had greatly improved 1 week later. When dextrocardia is present, using active fixation leads in the atrial and ventricular leads is easier for finding the pacing position with optimal sensing and pacing thresholds, and they reduce the incidence of falling off.
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