Multiple Labeling in Electron Microscopy: Its Application in Cardiovascular Research

The heart is a muscular pump kept together by a network of extracellular matrix components. An increase in collagens, as in chronic congestive heart failure (CHF), is thought to have a negative effect on cardiac compliance and, thus, on the clinical condition. Conventional electron microscopy allows for the study of cellular and extracellular components and scanning electron microscopy (SEM) can put these structures in three-dimensional perspective. However, in order to study extracellular matrix components in relation to cells, immunoelectron microscopy is superior. We have used this technique in our studies on heart failure. Heart specimens were fixed in 4% paraformaldehyde and 0.1% glutaraldehyde in sodium cacodylate buffer, dehydrated by the method of progressive lowering of temperature and embedded in LR Gold plastic. Immunolabeling could be achieved with different sized gold-conjugated secondary antibodies or protein-A gold conjugates. Depending on the objective, ultra small gold (USG) conjugates or a regular probe size can be used. Labeling efficiency could be increased by bridging antibodies. The double and triple staining procedures were based on single staining methods using one-and two-face labeling. The choice of antibodies and gold conjugates depended on the objectives. Immunoelectron microscopy, using multiple labeling, allowed a detailed study of the organization of the extracellular matrix and its relationship with cardiac myocytes. This may prove to be a useful tool for the study of chronic heart failure

Probing a non-biaxial behavior of infinitely thin hard platelets

We give a criterion to test a non-biaxial behavior of infinitely thin hard platelets of $D_{2h}$ symmetry based upon the components of three order parameter tensors. We investigated the nematic behavior of monodisperse infinitely thin rectangular hard platelet systems by using the criterion. Starting with a square platelet system, and we compared it with rectangular platelet systems of various aspect ratios. For each system, we performed equilibration runs by using isobaric Monte Carlo simulations. Each system did not show a biaxial nematic behavior but a uniaxial nematic one, despite of the shape anisotropy of those platelets. The relationship between effective diameters by simulations and theoretical effective diameters of the above systems was also determined.Comment: Submitted to JPS

Mammary-carcinoma cells in mouse liver: infiltration of liver tissue and interaction with Kupffer cells.

Interactions between TA3 mammary-carcinoma cells and liver cells were studied with the electron microscope in mouse livers that had been perfused with a defined medium containing the tumour cells. Infiltration of liver tissue by the TA3 cells proceeded in the following steps. First, numerous small protrusions were extended through endothelial cells and into hepatocytes. Next, some cells had larger processes deeply indenting hepatocytes. Finally a few tumour cells became located outside the blood vessels. Two variant cell lines, TA3/Ha and TA3/St, differing in cell coat and surface charge, did not differ in the extent of infiltration. TA3/Ha cells were often encircled by thin processes of liver macrophages (Kupffer cells). Encircled cells were initially intact, but later some of them degenerated. These observations suggest that TA3/Ha cells were phagocytized by the Kupffer cells. Encirclement appeared to be inhibited after only 30 min, when many cells were still partly surrounded. Encirclement of TA3/St was much less frequent. After injection of tumour cells intra-portally in vivo, similar results were obtained, which demonstrated the validity of the perfused liver model. TA3/Ha cells formed much fewer tumour nodules in the liver than TA3/St cells

Обработка оптических измерений траектории летательных объектов

Рассмотрены методы уравнивания угловых измерений по способу наименьших квадратов: метод уравнивания измерений отдельно в каждом временном сечении, предполагающий нулевое математическое ожидание случайных ошибок измерений, и метод уравнивания избыточных оптических измерений с подавлением их постоянных систематических ошибок в предположении засоренности измерений как случайными, так и неизвестными по величине и знаку систематическими погрешностями.Розглянуто методи зрівнювання кутових вимірювань за способом найменших квадратів: метод зрівнювання вимірювань окремо в кожному часовому розрізі, що передбачає нульове математичне очікування випадкових похибок вимірювань, і метод зрівнювання надлишкових оптичних вимірювань із заглушенням їх постійних систематичних похибок у припущенні засміченості вимірювань як випадковими, так і невідомими за величиною та знаком систематичними похибками.The methods of equalizing angular measurements according to the method of least squares are examined: the method of equalizing measurements separately in each temporary section, that assumes the zero mathematical expectation of the random errors of measurements, and the method of equalizing excessive optical measurements with suppression of their constant systematic errors under the assumption of the obstruction of measurements by systematic errors both random and unknowns by value and sign

A fabrication guide for planar silicon quantum dot heterostructures

We describe important considerations to create top-down fabricated planar quantum dots in silicon, often not discussed in detail in literature. The subtle interplay between intrinsic material properties, interfaces and fabrication processes plays a crucial role in the formation of electrostatically defined quantum dots. Processes such as oxidation, physical vapor deposition and atomic-layer deposition must be tailored in order to prevent unwanted side effects such as defects, disorder and dewetting. In two directly related manuscripts written in parallel we use techniques described in this work to create depletion-mode quantum dots in intrinsic silicon, and low-disorder silicon quantum dots defined with palladium gates. While we discuss three different planar gate structures, the general principles also apply to 0D and 1D systems, such as self-assembled islands and nanowires.Comment: Accepted for publication in Nanotechnology. 31 pages, 12 figure

Cyber Security: China and Russia\u27s Erosion of 21st Century United States\u27 Hegemony

With Russia and China emerging as challengers to U.S. hegemony, the use of cyber warfare could tilt the current balance of power in either of their favors. Using various methods, hackers can acquire sensitive information and destroy online infrastructures. In the development of cyber warfare, China has become a seasoned veteran with computer virus operations dating back to 199714. Russia has emerged as a cyber aggressor, as seen in Russia’s cyber attacks on several countries in the last decade. This paper argues that, with the growth of foreign cyber technology, the probability of cyberspace being used as a military front by state or non-state actors against the United States increases

Missense variants in ANKRD11 cause KBG syndrome by impairment of stability or transcriptional activity of the encoded protein

KBG syndrome; Missense variants; Neurodevelopmental disordersSíndrome KBG; Variants de missense; Trastorns del neurodesenvolupamentSíndrome KBG; Variantes de missense; Trastornos del neurodesarrolloPurpose Although haploinsufficiency of ANKRD11 is among the most common genetic causes of neurodevelopmental disorders, the role of rare ANKRD11 missense variation remains unclear. We characterized clinical, molecular, and functional spectra of ANKRD11 missense variants. Methods We collected clinical information of individuals with ANKRD11 missense variants and evaluated phenotypic fit to KBG syndrome. We assessed pathogenicity of variants through in silico analyses and cell-based experiments. Results We identified 20 unique, mostly de novo, ANKRD11 missense variants in 29 individuals, presenting with syndromic neurodevelopmental disorders similar to KBG syndrome caused by ANKRD11 protein truncating variants or 16q24.3 microdeletions. Missense variants significantly clustered in repression domain 2 at the ANKRD11 C-terminus. Of the 10 functionally studied missense variants, 6 reduced ANKRD11 stability. One variant caused decreased proteasome degradation and loss of ANKRD11 transcriptional activity. Conclusion Our study indicates that pathogenic heterozygous ANKRD11 missense variants cause the clinically recognizable KBG syndrome. Disrupted transrepression capacity and reduced protein stability each independently lead to ANKRD11 loss-of-function, consistent with haploinsufficiency. This highlights the diagnostic relevance of ANKRD11 missense variants, but also poses diagnostic challenges because the KBG-associated phenotype may be mild and inherited pathogenic ANKRD11 (missense) variants are increasingly observed, warranting stringent variant classification and careful phenotyping