Atomic Force Microscopy Study of Cross-Sections of Perovskite Layers

Improvement of methods for imaging of the volume structure of photoactive layers is one of the important directions towards development of highly efficient solar cells. In particular, volume structure of photoactive layer has critical influence on perovskite solar cell performance and life time. In this study, a perovskite photoactive layer cross-section was prepared by using Focused Ion Beam (FIB) and imaged by Atomic Force Microscopy (AFM) methods. The proposed approach allows using advances of AFM for imaging structure of perovskites in volume. Two different types of perovskite layers was investigated: FAPbBr3 and MAPbBr3. The heterogeneous structure inside film, which consist of large crystals penetrating the film as well as small particles with sizes of several tens nanometers, is typical for FAPbBr3. The ordered nanocrystalline structure with nanocrystals oriented at 45 degree to film surface is observed in MAPbBr3. An optimized sample preparation route, which includes FIB surface polishing by low energy Ga ions at the angles around 10 degree to surface plane, is described and optimal parameters of surface treatment are discussed. Use of AFM phase contrast method provides high contrast imaging of perovskite structure due to strong dependence of phase shift of oscillating probe on materials properties. The described method of imaging can be used for controllable tuning of perovskite structure by changes of the sample preparation routes

Replacement of the aortic valve, ascending aorta and arch in a patient with dextrocardia in the context of situs inversus totalis: a case report

The article discusses a rare case of successful replacement of the aortic valve, ascending  aorta and arch in a patient with dextrocardia  in the context  of situs inversus totalis. Situs inversus is a rare variant of normal anatomy  in which the major visceral organs are mirrored from their normal positions

Surgical treatment of cardiac echinococcosis: a case report

Echinococcosis refers is a chronic disease caused by tapeworms of the order Cyclophyllidea. Echinococcal cysts increase in size slowly and are often asymptomatic, and the symptoms of cardiac echinococcosis are nonspecific, which in turn can make diagnosis difficult. Early diagnosis and surgical treatment of this disease is crucial to prevent severe complications. Considering that the heart is affected extremely rarely, we want to demonstrate the successful surgical treatment

Pivotal Role of Inosine Triphosphate Pyrophosphatase in Maintaining Genome Stability and the Prevention of Apoptosis in Human Cells

Pure nucleotide precursor pools are a prerequisite for high-fidelity DNA replication and the suppression of mutagenesis and carcinogenesis. ITPases are nucleoside triphosphate pyrophosphatases that clean the precursor pools of the non-canonical triphosphates of inosine and xanthine. The precise role of the human ITPase, encoded by the ITPA gene, is not clearly defined. ITPA is clinically important because a widespread polymorphism, 94C>A, leads to null ITPase activity in erythrocytes and is associated with an adverse reaction to thiopurine drugs. We studied the cellular function of ITPA in HeLa cells using the purine analog 6-N hydroxylaminopurine (HAP), whose triphosphate is also a substrate for ITPA. In this study, we demonstrate that ITPA knockdown sensitizes HeLa cells to HAP-induced DNA breaks and apoptosis. The HAP-induced DNA damage and cytotoxicity observed in ITPA knockdown cells are rescued by an overexpression of the yeast ITPase encoded by the HAM1 gene. We further show that ITPA knockdown results in elevated mutagenesis in response to HAP treatment. Our studies reveal the significance of ITPA in preventing base analog-induced apoptosis, DNA damage and mutagenesis in human cells. This implies that individuals with defective ITPase are predisposed to genome damage by impurities in nucleotide pools, which is drastically augmented by therapy with purine analogs. They are also at an elevated risk for degenerative diseases and cancer

Oncogene homologue Sch9 promotes age-dependent mutations by a superoxide and Rev1/Polζ-dependent mechanism

Oncogenes contribute to tumorigenesis by promoting growth and inhibiting apoptosis. Here we examine the function of Sch9, the Saccharomyces cerevisiae homologue of the mammalian Akt and S6 kinase, in DNA damage and genomic instability during aging in nondividing cells. Attenuation of age-dependent increases in base substitutions, small DNA insertions/deletions, and gross chromosomal rearrangements (GCRs) in sch9Δ mutants is associated with increased mitochondrial superoxide dismutase (MnSOD) expression, decreased DNA oxidation, reduced REV1 expression and translesion synthesis, and elevated resistance to oxidative stress-induced mutagenesis. Deletion of REV1, the lack of components of the error-prone Polζ, or the overexpression of SOD1 or SOD2 is sufficient to reduce age-dependent point mutations in SCH9 overexpressors, but REV1 deficiency causes a major increase in GCRs. These results suggest that the proto-oncogene homologue Sch9 promotes the accumulation of superoxide-dependent DNA damage in nondividing cells, which induces error-prone DNA repair that generates point mutations to avoid GCRs and cell death during the first round of replication

Evening Telegram, 1919-10-10

The Evening Telegram began publication in St. John's on 3 April 1879 and remains in print today under the title The Telegram. It was published daily except Sunday through to 1958, the frequency changing thereafter. -- The total collection has been split into several parts; this portion contains the years 1919-1926

The infective endocarditis of synthetic patch after left ventricle reconstruction (Dor procedure)

Infective endocarditis (IE) has become an increasingly significant problem in cardiology and cardiac surgery over the past 30 years. Despite the noticeable progress made in the diagnosis and treatment of IE, the prognosis for this condition is still poor and the mortality rate reaches 15-30% [1, 2]. The risk of developing IE is especially high in patients with «intracardiac» artificial materials (artificial valves, prostheses of any type, implantable antiarrhythmic devices). This article presents a rare clinical case of   IE of synthetic patch after left ventricle reconstruction (Dor procedure)

Off-pump coronary artery bypass surgery in a patient with dextrocardia and situs inversus totalis: a case report

The article discusses a rare clinical case of successful off-pump coronary artery bypass surgery in a patient with dextrocardia and situs inversus totalis (SIT). SIT is a rare condition in which the arrangement of the internal organs is a mirror image of normal anatomy