Low-loss K-band Photoconductive Switches in SIW Technology

A design approach for mmWave switches in substrate integrated waveguide (SIW) technology is demonstrated. The switch is based on a photoconductive element (PE) which represents a piece of an intrinsic silicon wafer with light modulated conductivity. Using both dielectric (high-resistivity) and conductive states of the PE, we can design a low-loss mmWave switching element. Owing to the light actuation, the control circuitry of the photoconductive switch (PS) is electrically separated from the high-frequency elements of the device. This solves the bottleneck of conventional mmWave switches based on PIN diodes, MOSFETs, MEMS, etc., which are bulky and lossy due to decoupling filters and matching elements of control and biasing circuits. The proposed approach is generic and can be applied to many mmWave applications within 10\ua0—\ua0100\ua0GHz such as 5G, WiGig, automotive radars, and others

Integrated W-band Photoconductive Switches in SIW Technology

A novel approach for the design of mmWave substrate integrated waveguide (SIW) switches is presented. The switch is based on controllable photoconductive elements (PEs), whose conductivity is modulated by a light source. The PE is integrated on the top SIW metal plate and provides either a short-circuit or transmission operation regime, depending on the actuation conditions. Owing to the light actuation, the mmWave and DC control circuitry are naturally decoupled, which, in turn, makes the design low-loss and compact as compared to PIN diode and integrated circuit-based SIW switches implementations. We demonstrate two examples of SIW photoconductive switches (PSs) at W-band: single-pole single-throw (SPST) and single-pole double-throw (SPDT) PSs. Their operation principle, actuation, and parasitic radiation suppression are discussed. Measurements show the peak insertion loss of 0.9 and 2.2 dB, isolation better than 25 and 30 dB, and –10-dB impedance bandwidth of 21 and 15% for the SPST and SPDT PSs, respectively

Analysis of alternative splicing of cassette exons at single-cell level using two fluorescent proteins

Alternative splicing plays a major role in increasing proteome complexity and regulating gene expression. Here, we developed a new fluorescent protein-based approach to quantitatively analyze the alternative splicing of a target cassette exon (skipping or inclusion), which results in an open-reading frame shift. A fragment of a gene of interest is cloned between red and green fluorescent protein (RFP and GFP)-encoding sequences in such a way that translation of the normally spliced full-length transcript results in expression of both RFP and GFP. In contrast, alternative exon skipping results in the synthesis of RFP only. Green and red fluorescence intensities can be used to estimate the proportions of normal and alternative transcripts in each cell. The new method was successfully tested for human PIG3 (p53-inducible gene 3) cassette exon 4. Expected pattern of alternative splicing of PIG3 minigene was observed, including previously characterized effects of UV light irradiation and specific mutations. Interestingly, we observed a broad distribution of normal to alternative transcript ratio in individual cells with at least two distinct populations with ∼45% and >95% alternative transcript. We believe that this method is useful for fluorescence-based quantitative analysis of alternative splicing of target genes in a variety of biological models

Main pipeline repair by steel welding sockets

The presented study discusses the structures used for restoring the bearing capacity of the main pipeline sections in case of the corrosion damage. It is shown that a welded crimping socket the most frequently used in repair can efficiently reduce stress in the pipe walls only in close joints. To increase the repair structure efficiency, it is proposed to place an elastic layer between a pipe and a socket which can fill the space and transfer a part of load from the pipe to the socket. The elastic layer material must be, first, soft enough to completely fill a gap between the pipe and the socket considering the pipe surface irregularity. Secondly, the material must be characterized by a sufficiently large elastic modulus (in the range of 1000 MP

The classification of endoscopy images with persistent homology

Aiming at the automatic diagnosis of tumors from narrow band imaging (NBI) magnifying endoscopy (ME) images of the stomach, we combine methods from image processing, computational topology, and machine learning to classify patterns into normal, tubular, vessel. Training the algorithm on a small number of images of each type, we achieve a high rate of correct classifications. The analysis of the learning algorithm reveals that a handful of geometric and topological features are responsible for the overwhelming majority of decisions

The Ross Procedure in Patients among the Pediatric Population, Post Ten Years of Experience

The aim of the study was to analyze the results of the surgical treatment in pediatric patients who had undergone the Ross procedure.Material and Methods: The study involved 114 patients between 12 days to 18 years in age. The early and late (up to 5 years) results of the treatment were studied. The examination included echocardiography, catheterization of the cardiac chambers and angiocardiography. The case distribution of patients based on diagnosis was as follows: isolated aortic valve stenosis (IAVS) in 38 (33.3%) patients, aortic valve insufficiency (AVI) in 33 (28.9%), and combined heart defects in 56 patients (49.1%).Results: The death rate was 6.14% during the early postoperative period and 1.14% in the late postoperative period; the actuarial survival in the long-term was 98.86%. The complication rate was 51.5%. The most frequent complication was pericarditis (25.6%), whereas cardiac and respiratory failure occurred in 7.6% of the cases and cardiac arrhythmias in 6.1% of the cases. The average time spent in the intensive care unit was 3.48 ± 2.90 days; the hospitalization period on average was 24.70±10.87 days. After surgery, there was a tendency of the echocardiographic parameters to move toward normalization. The frequency of reoperation in the late period was 23.7%, the main reason for which being the conduit dysfunction in the position of the pulmonary artery (PA).Conclusion: The clinical efficacy of the Ross procedure in the treatment of aortic valve malformations in the pediatric group was confirmed. However, in some cases, the need to perform repeated operations due to the increase in the ring size and an increase in the neo-aortic insufficiency during the somatic growth process

Outcomes of the Ross Procedure in the Pediatric Population

The Ross procedure (RP) is considered by many authors as the best option for aortic valve replacement in young children and adolescents. This paper presents the results of the immediate and late postoperative period (more than 5 years) after the RP among pediatric patients

Analysis of polymorphic sites in the promoter of the nitric oxide synthase 2 gene

A point mutation (G -> C) in the gene promoter for the human nitric oxide synthase (NOS) 2 at position -954 is associated with protection against severe Plasmodium falciparum malaria in Gabon. Carriers of this mutation show higher basal levels of nitric oxide production than wild type individuals. To obtain information about the possible binding transcription factors, nucleic proteins from the lung carcinoma cell line were enriched by affinity chromatography using DEAE-Sepharose and immobilized oligonucleotides derived from the promoter sequence. A mutational analysis was performed on 30 samples to detect polymorphisms in the NOS2 promoter region that contains important NF-kappa B sites. Three point mutations were identified in this region. In vitro studies with promoter constructs showed an altered expression of the marker gene depending on the promoter variant used