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The phenomenon of internal initiation of translation was discovered in 1988 on poliovirus mRNA. The prototypic cis-acting element in the 5′ untranslated region (5′UTR) of poliovirus mRNA, which is able to direct initiation at an internal start codon without the involvement of a cap structure, has been called an IRES (Internal Ribosome Entry Site or Segment). Despite its early discovery, poliovirus and other related IRES elements of type I are poorly characterized, and it is not yet clear which host proteins (a.k.a. IRES trans-acting factors, ITAFs) are required for their full activity in vivo. Here we discuss recent and old results devoted to type I IRESes and provide evidence that Poly(rC) binding protein 2 (PCBP2), Glycyl-tRNA synthetase (GARS), and Cold Shock Domain Containing E1 (CSDE1, also known as UNR) are major regulators of type I IRES activity. [ABSTRACT FROM AUTHOR]

Ribosome profiling (riboseq) has opened the possibilities for the genome-wide studies of translation in all living organisms. This method is based on deep sequencing of mRNA fragments protected by the ribosomes from hydrolysis by ribonucleases, the so-called ribosomal footprints (RFPs). Ribosomal profiling together with RNA sequencing allows not only to identify with a reasonable accuracy translated reading frames in the transcriptome, but also to track changes in gene expression in response to various stimuli. Notably, ribosomal profiling in its classical version has certain limitations. The size of the selected mRNA fragments is 25-35 nts, while RFPs of other sizes are usually omitted from analysis. Also, ribosomal profiling "averages" the data from all ribosomes and does not allow to study specific ribosomal complexes associated with particular translation factors. However, recently developed modifications of ribosomal profiling provide answers to a number of questions. Thus, it has become possible to analyze not only elongating, but also scanning and reinitiating ribosomes, to study events associated with the collision of ribosomes during mRNA translation, to discover new ways of cotranslational assembly of multisubunit protein complexes during translation, and to selectively isolate ribosomal complexes associated with certain protein factors. New data obtained using these modified approaches provide a better understanding of the mechanisms of translation regulation and the functional roles of translational apparatus components. [ABSTRACT FROM AUTHOR]

Cerebrospinal fistulas of the clivus region often result from previous surgical intervention at the skull base. The localization and size of the fistula determine the appropriate treatment strategy. When flap closure is not possible, the microsuture technique with autograft placement provides a favorable outcome. We present a technical report on the application of the microsuture technique for clivus region cerebrospinal fluid fistula closure in a patient with previous chordoma treatment and nonspecific coronavirus disease 2019 complications. The application of the microsuture technique resulted in stable remission of the fistula and complete regression of the clinical manifestations. The microsuture technique for clivus region fistula closure is a potentially valuable alternative to vascularized flap closure. [ABSTRACT FROM AUTHOR]

This paper reports the results of a study of a water-gas shift reaction over nickel-ceria catalysts with different metal loading. Within this study, the overall CO conversion and observed kinetic behavior were investigated over the temperature range of 250-550 °C in different reactor configurations (fixed-bed and microchannel reactors). The quasi-steady state kinetics of the CO water-gas shift reaction was studied for fractions of Ni-containing cerium oxide catalysts in fixed-bed experiments at lab-scale level using a very dilute gas (1% CO + 1.8% H2O in He). A set of experiments with a microchannel reactor was performed using the feed composition (CO:H2O:H2:N2 = 1:2:2:2), representing a product gas from methane partial oxidation. The results were interpreted using computational models. The kinetic parameters were determined by regression analysis, while mechanistic aspects were considered only briefly. Simulation of the WGS reaction in the microreactor was also carried out by using the COMSOL Multiphysics program. [ABSTRACT FROM AUTHOR]

Mitochondrial polarisation is paramount for a variety of cellular functions. Under ischemia, mitochondrial membrane potential (ΔΨm) and proton gradient (ΔpH) are maintained via a reversal of mitochondrial F1Fo ATP synthase (mATPase), which can rapidly deplete ATP and drive cells into energy crisis. We found that under normal conditions in cells with disassembled cytochrome c oxidase complex (COX-deficient HCT116), mATPase maintains ΔΨm at levels only 15–20% lower than in WT cells, and for this utilises relatively little ATP. For a small energy expenditure, mATPase enables mitochondrial ΔpH, protein import, Ca 2+ turnover, and supports free radical detoxication machinery enlarged to protect the cells from oxidative damage. Whereas in COX-deficient cells the main source of ATP is glycolysis, the ΔΨm is still maintained upon inhibition of the adenine nucleotide translocators with bongkrekic acid and carboxyatractyloside, indicating that the role of ANTs is redundant, and matrix substrate level phosphorylation alone or in cooperation with ATP-Mg/P i carriers can continuously support the mATPase activity. Intriguingly, we found that mitochondrial complex III is active, and it contributes not only to free radical production, but also to ΔΨm maintenance and energy budget of COX-deficient cells. Overall, this study demonstrates that F1Fo ATP synthase can support general mitochondrial and cellular functions, working in extremely efficient ‘energy saving’ reverse mode and flexibly recruiting free radical detoxication and ATP producing / transporting pathways. [ABSTRACT FROM AUTHOR]

Objective To conduct a comparative analysis of 2 groups of patients with skull base chordomas extending onto the craniovertebral junction, who underwent surgical treatment using extracranial approaches with and without craniocervical fusion. Methods The study group included 29 patients with skull base chordomas, extending to the craniovertebral junction, who were operated on from 2000 to 2015. The patients underwent the following surgical treatment: posterior craniocervical fusion followed by tumor removal using transoral and combined transoral and transnasal approaches. The reference group included 21 patients with the same disease, who underwent tumor removal surgery using the transoral approach without craniocervical fusion. Results In the study group, in 27.5% of all cases (8 patients), the tumors were removed radically; in 65.5% of all cases (19 patients), the tumors were removed subtotally; and in 7% of all cases (2 patients), the tumors were removed partially. In the reference group, the extent of surgical radicality was as follows: radical, 0%; subtotal, 19% (4 cases); partial, 81% (17 cases). Conclusions Use of the proposed surgical technique in clinical practice may help increase the radicality of tumor excisions, decrease the number of postoperative complications, accelerate the rehabilitation process, and increase the quality of life in patients with skull base tumors extending to the craniovertebral junction. [ABSTRACT FROM AUTHOR]

Protein synthesis in eukaryotes is subject to stringent control. The misregulation of translation of certain mRNAs is often a hallmark of many diseases, including malignancies and autoimmune disorders. To understand why and how it happens, it is important to investigate the translational control of specific mRNAs. In this case, one could use reporter mRNAs in order to identify cis -acting elements responsible for regulation. Here we overview plasmid DNA (pDNA) and mRNA transfections, their pitfalls and limitations, as well as some emerging applications for mRNA transfection. [ABSTRACT FROM AUTHOR]

The article examines the immediate effect of sodium arsenite treatment on protein synthesis. Topics discussed include the role of eukaryotic cells in the rapid reduction in protein synthesis in response to various stress conditions and the phosphorylation-mediated inactivation of the eukaryotic initiation factor 2. The presence of at least one efficiently translated upstream open reading frame in nearly all resistant transcripts and its role in functional protein product encoding are mentioned.

Background: Ribosome profiling (ribo-seq) provides experimental data on the density of elongating or initiating ribosomes at the whole transcriptome level that can be potentially used for estimating absolute levels of translation initiation at individual Translation Initiation Sites (TISs). These absolute levels depend on the mutual organisation of TISs within individual mRNAs. For example, according to the leaky scanning model of translation initiation in eukaryotes, a strong TIS downstream of another strong TIS is unlikely to be productive, since only a few scanning ribosomes would be able to reach the downstream TIS. In order to understand the dependence of translation initiation efficiency on the surrounding nucleotide context, it is important to estimate the strength of TISs independently of their mutual organisation, i.e. to estimate with what probability a ribosome would initiate at a particular TIS. Results: We designed a simple computational approach for estimating the probabilities of ribosomes initiating at individual start codons using ribosome profiling data. The method is based on the widely accepted leaky scanning model of translation initiation in eukaryotes which postulates that scanning ribosomes may skip a start codon if the initiation context is unfavourable and continue on scanning. We tested our approach on three independent ribo-seq datasets obtained in mammalian cultured cells. Conclusions: Our results suggested that the method successfully discriminates between weak and strong TISs and that the majority of numerous non-AUG TISs reported recently are very weak. Therefore the high frequency of non-AUG TISs observed in ribosome profiling experiments is due to their proximity to mRNA 5′-ends rather than their strength. Detectable translation initiation at non-AUG codons downstream of AUG codons is comparatively infrequent. The leaky scanning method will be useful for the characterization of differences in start codon selection between tissues, developmental stages and in response to stress conditions. [ABSTRACT FROM AUTHOR]

Despite the wide variety of available cationic lipid platforms for the delivery of nucleic acids into cells, the optimization of their composition has not lost its relevance. The purpose of this work was to develop multi-component cationic lipid nanoparticles (LNPs) with or without a hydrophobic core from natural lipids in order to evaluate the efficiency of LNPs with the widely used cationic lipoid DOTAP (1,2-dioleoyloxy-3-[trimethylammonium]-propane) and the previously unstudied oleoylcholine (Ol-Ch), as well as the ability of LNPs containing GM3 gangliosides to transfect cells with mRNA and siRNA. LNPs containing cationic lipids, phospholipids and cholesterol, and surfactants were prepared according to a three-stage procedure. The average size of the resulting LNPs was 176 nm (PDI 0.18). LNPs with DOTAP mesylate were more effective than those with Ol-Ch. Core LNPs demonstrated low transfection activity compared with bilayer LNPs. The type of phospholipid in LNPs was significant for the transfection of MDA-MB-231 and SW 620 cancer cells but not HEK 293T cells. LNPs with GM3 gangliosides were the most efficient for the delivery of mRNA to MDA-MB-231 cells and siRNA to SW620 cells. Thus, we developed a new lipid platform for the efficient delivery of RNA of various sizes to mammalian cells. [ABSTRACT FROM AUTHOR]

Background: In crustaceans, several mechanisms provide for the mechanical strength of the cuticular "tools" (dactyli, claws, jaws), which serve to catch and crush food objects. Studies on the mandibles of the endemic Baikal amphipod Acanthogammarus grewingkii by means of electron microscopy and elemental analysis have revealed specific structural features of these mouthparts. Methodology: The fine structure of the mandible has been studied by means of SEM, TEM, and AFM; methods used to analyze its elemental and phase composition include XEPMA, XPS, SEM-EDS analysis, and XRD. Conclusion: Functional adaptations of the mandible in A. grewingkii provide for the optimum combination of mechanical hardness and fracture resistance, which is achieved due to a complex structure and composition of its cutting parts. Teeth of the mandible are covered by a thin layer of silica (10-20 mm). Their epicuticle is characterized by a high density, consists of three layers, and increases in thickness toward the tooth apex. The epicuticle is enriched with Br, while the concentrations of Ca and P reach the peak values in the softer internal tissues of the teeth. These data broaden the view of the diversity of adaptation mechanisms providing for the strengthening of cuticular "tools" in crustaceans [ABSTRACT FROM AUTHOR]

Ribosomal frameshifting (RFS) at the slippery site of SARS-CoV-2 RNA is essential for the biosynthesis of the viral replication machinery. It requires the formation of a pseudoknot (PK) structure near the slippery site and can be inhibited by PK-disrupting oligonucleotide-based antivirals. We obtained and compared three types of such antiviral candidates, namely locked nucleic acids (LNA), LNA–DNA gapmers, and G-clamp-containing phosphorothioates (CPSs) complementary to PK stems. Using optical and electrophoretic methods, we showed that stem 2-targeting oligonucleotide analogs induced PK unfolding at nanomolar concentrations, and this effect was particularly pronounced in the case of LNA. For the leading PK-unfolding LNA and CPS oligonucleotide analogs, we also demonstrated dose-dependent RSF inhibition in dual luciferase assays (DLAs). Finally, we showed that the leading oligonucleotide analogs reduced SARS-CoV-2 replication at subtoxic concentrations in the nanomolar range in two human cell lines. Our findings highlight the promise of PK targeting, illustrate the advantages and limitations of various types of DNA modifications and may promote the future development of oligonucleotide-based antivirals. [ABSTRACT FROM AUTHOR]

Mitochondrial membrane potential (DYm) is one of the key drivers of free radical production. Changes in DYm strongly affect free radical turnover in both mitochondria and cytosol. We found that in cytochrome c oxidase deficient HCT116 cells F1Fo ATP synthase (mATPase) is reversed in order to maintain DYm polarisation. For small energy costs, mATPase enables mitochondrial protein import, Ca 2+ turnover and Krebs cycle activity. Although glycolysis is the main source of ATP in COX-deficient cells, the DYm does not decrease upon inhibition of the adenine nucleotide translocators, suggesting their redundant role. The ATP-Mg/Pi carriers and substrate level phosphorylation can continuously support the mATPase activity and hence DYm polarisation. Intriguingly, in COX-deficient cells complex III contributes to DYm maintenance, redox state, and free radical (H 2 O 2 ) production. An enlarged mitochondrial free radical detoxification machinery (e.g. elevated SOD2) protects the cells from oxidative damage. Although cytosol is known as the main area of free radical synthesis in COX-deficient HCT116 cells, and NAD(P)H levels are increased, the expression of genes involved in glutathione-dependent reactions does not change, suggesting an involvement of alternative mechanisms of free radical quenching. An observed large increase in fatty acid deposition is likely to contribute to cell protection. [ABSTRACT FROM AUTHOR]

mRNAs lacking 5′ untranslated regions (leaderless mRNAs) are molecular relics of an ancient translation initiation pathway. Nevertheless, they still represent a significant portion of transcriptome in some taxons, including a number of eukaryotic species. In bacteria and archaea, the leaderless mRNAs can bind non-dissociated 70 S ribosomes and initiate translation without protein initiation factors involved. Here we use the Fleeting mRNA Transfection technique (FLERT) to show that translation of a leaderless reporter mRNA is resistant to conditions when eIF2 and eIF4F, two key eukaryotic translation initiation factors, are inactivated in mammalian cells. We report an unconventional translation initiation pathway utilized by the leaderless mRNA in vitro, in addition to the previously described 80S-, eIF2-, or eIF2D-mediated modes. This mechanism is a bacterial-like eIF5B/IF2-assisted initiation that has only been reported for hepatitis C virus-like internal ribosome entry sites (IRESs). Therefore, the leaderless mRNA is able to take any of four different translation initiation pathways in eukaryotes. [ABSTRACT FROM AUTHOR]

An abstract of the article "Influence Of Adsorbed Organic Molecules On The Critical Parameters Of HTSC Ceramics Part I: YBa2Cu3O7-x Treated With Phenidone And Hydroquinone" by Lev L. Makarshin and colleagues is presented.

Activated ghrelin receptor GHS-R1α triggers cell signalling pathways that modulate energy homeostasis and biosynthetic processes. However, the effects of ghrelin on mRNA translation are unknown. Using various reporter assays, here we demonstrate a rapid elevation of protein synthesis in cells within 15–30 min upon stimulation of GHS-R1α by ghrelin. We further show that ghrelin-induced activation of translation is mediated, at least in part, through the de-phosphorylation (de-suppression) of elongation factor 2 (eEF2). The levels of eEF2 phosphorylation at Thr56 decrease due to the reduced activity of eEF2 kinase, which is inhibited via Ser366 phosphorylation by rpS6 kinases. Being stress-susceptible, the ghrelin-mediated decrease in eEF2 phosphorylation can be abolished by glucose deprivation and mitochondrial uncoupling. We believe that the observed burst of translation benefits rapid restocking of neuropeptides, which are released upon GHS-R1α activation, and represents the most time- and energy-efficient way of prompt recharging the orexigenic neuronal circuitry. [ABSTRACT FROM AUTHOR]

The protein antizyme is a negative regulator of cellular polyamine concentrations from yeast to mammals. Synthesis of functional antizyme requires programmed +1 ribosomal frameshifting at the 3' end of the first of two partially overlapping ORFs. The frameshift is the sensor and effector in an autoregulatory circuit. Except for Saccharomyces cerevisiae antizyme mRNA, the frameshift site alone only supports low levels of frameshifting. The high levels usually observed depend on the presence of cis-acting stimulatory elements located 5' and 3' of the frameshift site. Antizyme genes from different evolutionary branches have evolved different stimulatory elements. Prior and new multiple alignments of fungal antizyme mRNA sequences from the Agaricomycetes class of Basidiomycota show a distinct pattern of conservation 5' of the frameshift site consistent with a function at the amino acid level. As shown here when tested in Schizosaccharomyces pombe and mammalian HEK293T cells, the 5' part of this conserved sequence acts at the nascent peptide level to stimulate the frameshifting, without involving stalling detectable by toe-printing. However, the peptide is only part of the signal. The 3' part of the stimulator functions largely independently and acts at least mostly at the nucleotide level. When polyamine levels were varied, the stimulatory effect was seen to be especially responsive in the endogenous polyamine concentration range, and this effect may be more general. A conserved RNA secondary structure 3' of the frameshift site has weaker stimulatory and polyamine sensitizing effects on frameshifting. [ABSTRACT FROM AUTHOR]

Unlike bacteria, a specialized eukaryotic initiation factor (eIF)-2, in the form of the ternary complex eIF2–GTP–Met-tRNAi Met, is used to deliver the initiator tRNA to the ribosome in all eukaryotic cells. Here we show that the hepatitis C virus (HCV) internal ribosome entry site (IRES) can direct translation without eIF2 and its GTPase-activating protein eIF5. In addition to the general eIF2- and eIF5-dependent pathway of 80S complex assembly, the HCV IRES makes use of a bacterial-like pathway requiring as initiation factors only eIF5B (an analog of bacterial IF2) and eIF3. The switch from the conventional eukaryotic mode of translation initiation to the eIF2-independent mechanism occurs when eIF2 is inactivated by phosphorylation under stress conditions. [ABSTRACT FROM AUTHOR]

Abscesses of the chiasmatic-sellar region are quite rare and are often a result of surgical intervention, trauma, or tumor growth. Primary abscesses are extremely rare and represent a group of abscesses the occur because of internal microbial seeding. Primary abscesses are rarely reported. We present 2 clinical cases featuring primary abscesses of the chiasmal-sellar region. To put into perspective the rarity of these findings, we performed a systematic review of existing clinical reports regarding this pathology. A systematic review of literature was conducted to gather existing clinical reports on primary abscesses of the chiasmatic-sellar region. Two personal findings are added to the literature review, including a 13-year-old girl and a 58-year-old man who presented with chiasmal-sellar region primary abscesses. The diagnostic aspects, treatment strategy, and outcomes are discussed. Both patients included in the report had positive outcome. The pediatric patient developed a recurrence of the abscess and was treated accordingly. Overall, 41 cases of primary abscesses of this region have been reported in literature, of which 6 are in children under 18 years of age. The main nonspecific clinical manifestations include headaches, visual impairment, and endocrine pathology. Acute inflammatory responses are rarely seen, despite infectious genesis. Transnasal endoscopic surgical treatment offers diagnostic and treatment advantages. Proper diagnostic procedures can aid in correct treatment strategy and improve overall outcome. [ABSTRACT FROM AUTHOR]

Interest in endoscopic transnasal access has increased with continued technological advances in endoscopic technology. The goals of this study were to review the normal anatomy in transnasal endoscopic neurosurgery and outline the anatomical basis for an expanded surgical approach. Defining anatomical aspects of surgical endoscopy helps guide the surgeon by defining normal anatomy of the access vector. This anatomic study was conducted on 15 adult male cadaver specimens using various microsurgical tools and endoscopic instruments and 1 intraoperative case. The vasculature was injected with colored silicone to aid visualization. Different transnasal approach techniques were used, with angles of endoscope access at 0°, 30°, 45°, and 70° accordingly for extensive anatomical mapping. The proximity of critical structures is different in each approach degree. A full understanding of the possible structures to be met during transnasal access is described. As a result of the study, anatomical aspects and important structures were outlined, and a surgical protocol was defined for minimal risk access in respect to normal anatomy of the area. Thorough knowledge of topographic anatomy of the craniovertebral junction is required for performing minimal-risk surgical intervention in this region. It is important to know all anatomical aspects of the transnasal approach in order to reduce the risk of damage to vital structures. Transnasal endoscopic surgery of the craniovertebral junction is a relatively new direction in neurosurgery; therefore, anatomical studies such as the one described in this article are extremely important for the development of this access method. [ABSTRACT FROM AUTHOR]

Introduction: Germinogenic central nervous system (CNS) tumors represent a heterogeneous group of tumors, constituting approximately 0.4% of all primary brain tumors. Removal of the tumor has no prognostic value. In "pure" primary germinomas of the CNS, the alpha-fetoprotein and human chorionic gonadotropin levels are within normal limits, and no specific biochemical tumor markers currently exist for this tumor type, making histological verification crucial for the choice of treatment tactics. When the tumor is located in the chiasmosellar region, one of the possible verification methods is endoscopic endonasal transsphenoidal biopsy. Objective: the main objective of the study is to demonstrate the feasibility and safety of endoscopic transsphenoidal approach for histological verification of primary germinomas of the CNS with chiasmosellar localization. Materials and Methods: The current study includes 13 patients with "pure" germinomas of the chiasmosellar region who underwent endoscopic endonasal surgical interventions with subsequent treatment according to the "Germinoma 2008" protocol. Results: The extent of surgical intervention ranged from biopsy (4) to partial (5) and total (4) removal of the tumor. In all cases, histological verification of the diagnosis was achieved and none of the patients presented with cerebrospinal fluid leaks and/or meningitis in the postoperative period, allowing to evaluate endoscopic intervention in our patient series as safe and effective. Two out of 13 patients were lost to follow-up. Conclusion: The endoscopic endonasal approach for histological verification and removal of chiasmosellar region germinomas is safe, and in some cases, less traumatic for the patient than transcranial and transventricular approaches. [ABSTRACT FROM AUTHOR]

Abstract Short upstream open reading frames (uORFs) are the most prevalent cis -acting regulatory elements in the mammalian transcriptome which can orchestrate mRNA translation. Apart from being "passive roadblocks" that decrease expression of the main coding regions, particular uORFs can serve as specific sensors for changing conditions, thus regulating translation in response to cell stress. Here we report a novel uORF-based regulatory mechanism that is employed under conditions of hyperosmotic stress by at least two human mRNAs, coding for translation reinitiation/recycling factor eIF2D and E3 ubiquitin ligase MDM2. This novel mode of translational control selectively downregulates their expression and requires as few as one uORF. Using a set of reporter mRNAs and fleeting mRNA transfection (FLERT) technique, we provide evidence that the phenomenon does not rely on delayed reinitiation, altered AUG recognition, ribosome stalling, mRNA destabilization or other known mechanisms. Instead, it is based on events taking place at uORF stop codon or immediately downstream. Functional aspects and implications of the novel regulatory mechanism to cell physiology are discussed. Graphical abstract Image 1 Highlights • uORFs regulate translation of more than half of human mRNAs. • A novel uORF-based regulatory mechanism is employed by human MDM2 and eIF2D mRNAs. • Translation of MDM2 and eIF2D mRNAs is specifically inhibited during osmotic stress. • The inhibition is based on events occurring at uORF stop codon or downstream. • Translation repression of MDM2 mRNA contributes to stress-induced cell cycle arrest. [ABSTRACT FROM AUTHOR]

Introduction With the introduction into the neurosurgical practice of minimally invasive methods using endoscopic techniques, it became possible to effectively remove hard-to-reach tumors, including central tumors of the anterior region of the posterior cranial fossa. Objective To analyze the results of surgical treatment of patients with various centrally located tumors of the base of the skull that extend into the anterior region of the posterior cranial fossa using the endoscopic endonasal transclival approach. Methods The personal surgical experience of the first author is 136 patients with various tumors (e.g., chordomas, meningiomas, pituitary adenomas, and fibrous dysplasia). Results Radicality of tumor removal was total 61.03%; subtotal 25%; partial 13.23%; and insufficient removal 0.74%. Postoperative cerebrospinal fluid leaks occurred in 9 cases (6.62%) and meningitis in 13 cases (9.56%). In 2 cases, surgical treatment had a lethal outcome (1.47%). Conclusions The endoscopic endonasal transclival approach can be used to obtain access to centrally located skull base tumors. This approach allows for a radical and low-risk removal of various skull base tumors of central localization that, until recently, were considered to be almost inoperable. Highlights • We present our experience of endoscopic endonasal transclival removal of mid located skull base tumors. • Personal surgical experience of the first author is 136 patients with various tumors (chordomas, meningiomas, etc.). • This approach allows for a radical and low-risk removal of various skull base tumors of central localization. [ABSTRACT FROM AUTHOR]

Objective To present the basic topographic and anatomic features of the clivus and adjacent structures with an objective of possible improvements and optimization of the extended endoscopic endonasal posterior (transclival) approach when removing tumors of the clivus and anterior regions of the posterior cranial fossa. Materials and Methods A craniometric study was conducted on 125 human skulls. A topographic anatomic study was conducted on 25 cadaver head specimens with arterial and venous beds stained with colored silicone, according to the method developed by us, to visualize its features and individual variability. Results The most important anatomic features of the external and internal regions of the clivus and the adjacent neural and vascular structures were analyzed. An accessible zone for the most effective transclival approach to the posterior cranial fossa is also specified. Conclusion The endoscopic endonasal transclival approach can be used to obtain access to centrally located tumors of the posterior cranial fossa. It is an alternative to transcranial approaches in the surgical treatment of tumors of the clivus. Highlights • We present our results of craniometric study on 125 human skulls. A topographic anatomical study was conducted on 25 cadaver head specimens. • The anatomical landmarks of a number of anatomical structures, necessary to perform the endoscopic endonasal posterior approach are described. • Upper, middle and lower transclival approaches provide access to the anterior surface neurovascular complexes of the posterior cranial. [ABSTRACT FROM AUTHOR]

Background A thorough understanding of the central nervous system anatomy is a fundamental part of a neurosurgeon's training. Development of novel neurosurgical approaches and optimization of existing ones directly depend on the comprehensive study of topographic anatomy of the head and neck using cadaveric specimens. Staining the vessels of the arterial and venous systems of a cadaveric specimen aids a detailed study of the vascularization of anatomic structures of the brain. Here we describe an alternative expedited method for creating anatomic preparations of the human brain using colored silicone for vascular perfusion staining. Methods A nonfixed, whole cadaver (with the head intact), without central nervous system pathology, no later than 48 hours after death, is used to prepare the human brain specimen through staining of arterial and venous vessels. Results Our proposed method provides a fast and inexpensive approach to making anatomic preparations of the human brain with staining of the vascular system. The preparations thus obtained can be used for educational purposes, aiding the study of normal and topographic anatomy of the brain, as well as the development of new microsurgical and/or endoscopic approaches. Conclusions In experienced hands, our proposed method allows the creation of anatomic preparations relatively fast, at low cost, and with excellent quality. [ABSTRACT FROM AUTHOR]

Introduction Intraoperative identification of cranial nerves is crucial for safe surgery of skull base tumors. Currently, only a small number of published papers describe the technique of trigger electromyography (t-EMG) in endoscopic endonasal removal of such tumors. Objective To assess the effectiveness of t-EMG in preventing intraoperative cranial nerve damage in endoscopic endonasal surgery of skull base tumors. Materials and Methods Nine patients were operated on using the endoscopic endonasal approach within a 1-year period. The tumors included large skull base chordomas and trigeminal neurinomas localized in the cavernous sinus. During the surgical process, cranial nerve identification was carried out using monopolar and bipolar t-EMG methods. Assessment of cranial nerve functional activity was conducted both before and after tumor removal. Results We mapped 17 nerves in 9 patients. Third, fifth, and sixth cranial nerves were identified intraoperatively. There were no cases of postoperative functional impairment of the mapped cranial nerves. In one case we were unable to get an intraoperative response from the fourth cranial nerve and observed its postoperative transient plegia (the function was normal before surgery). Conclusion t-EMG allows surgeons to control the safety of cranial nerves both during and after skull base tumor removal. [ABSTRACT FROM AUTHOR]

In this study, a modified technique of control current stress to investigation thin gate dielectric of MIS structures is proposed. This technique allows to monitor charge trapping in gate dielectric of MIS structures under high-field and another stress situations (irradiation, plasma, hot carriers, etc.). The technique also may be used for testing thin gate dielectric defects. Unlike simple techniques, for example constant current stress and J-ramp current stress, the proposed method uses a sequence of stress current and measuring current pulses. At the same time, the processes of charging and discharging of the MIS structure capacitance as well as the charge trapping in the gate dielectric are taken into account. Charging of MIS structure from inversion to accumulation modes or back way allows one to retrieve a low frequency capacitive-voltage characteristic. Account charging capacitance of MIS structure and charge trapping in gate dielectric at injective mode lets considerably increase metrological characteristics of this technique and reduce inaccuracies. The models describing the change in the charge state of MIS structures, both in the charge capacity, and in the mode of injection of charge carriers were developed. Using these models let to choose optimal algorithm of current stress and increase measurement accuracy. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The effect of high-field injection-thermal and irradiation treatments on the MIS structures reliability and defect reduction in the nanoscale gate dielectric has been investigated. Injection-thermal treatment (ITT) of MIS structures consisted of high-field electron injection into gate dielectric with the charge of defined value and subsequent parameter stabilization of MIS structures by means of thermal annealing. The MIS structures have been studied using novel techniques of multilevel current stress. Our study shows that the ITT can improve reliability of MIS structures (increase of charge-to-breakdown value) and identify defective structures. The ITT provides structural modification of SiO2 and Si-SiO2 interfaces. It has been shown that the ITT at elevated temperatures can reduce the reliability of MIS devices. Performing ITT at high temperatures leads to decrease of charge-to-breakdown average value in MIS structures. It has been demonstrated that irradiation treatment allows to reduce density of defects in thermal SiO2 films, SiO2 films doped with phosphorus, oxynitride films and as a result to increase reliability of MIS devices. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]