Immortality Research Articles

Application of the Key Characteristics of Carcinogens to Per and Polyfluoroalkyl Substances.

Per- and polyfluoroalkyl substances (PFAS) constitute a large class of environmentally persistent chemicals used in industrial and consumer products. Human exposure to PFAS is extensive, and PFAS contamination has been reported in drinking water and food supplies as well as in the serum of nearly all people. The most well-studied member of the PFAS class, perfluorooctanoic acid (PFOA), induces tumors in animal bioassays and has been associated with elevated risk of cancer in human populations. GenX, one of the PFOA replacement chemicals, induces tumors in animal bioassays as well. Using the Key Characteristics of Carcinogens framework for cancer hazard identification, we considered the existing epidemiological, toxicological and mechanistic data for 26 different PFAS. We found strong evidence that multiple PFAS induce oxidative stress, are immunosuppressive, and modulate receptor-mediated effects. We also found suggestive evidence indicating that some PFAS can induce epigenetic alterations and influence cell proliferation. Experimental data indicate that PFAS are not genotoxic and generally do not undergo metabolic activation. Data are currently insufficient to assess whether any PFAS promote chronic inflammation, cellular immortalization or alter DNA repair. While more research is needed to address data gaps, evidence exists that several PFAS exhibit one or more of the key characteristics of carcinogens.

Telomerase inhibition, telomere attrition and proliferation arrest of cancer cells induced by phosphorothioate ASO-NLS conjugates targeting hTERC and siRNAs targeting hTERT

Telomerase activity has been regarded as a critical step in cellular immortalization and carcinogenesis and because of this, regulation of telomerase represents an attractive target for anti-tumor specific therapeutics. Recently, one avenue of cancer research focuses on antisense strategy to target the oncogenes or cancer driver genes, in a sequence specific fashion to down-regulate the expression of the target gene. The protein catalytic subunit, human telomerase reverse transcriptase (hTERT) and the template RNA component (hTERC) are essential for telomerase function, thus theoretically, inhibition of telomerase activity can be achieved by interfering with either the gene expression of hTERT or the hTERC of the telomerase enzymatic complex. The present study showed that phosphorothioate antisense oligonucleotide (sASO)-nuclear localization signal (NLS) peptide conjugates targeting hTERC could inhibit telomerase activity very efficiently at 5 μM concentration but less efficiently at 1 μM concentration. On the other hand, siRNA targeting hTERT mRNA could strongly suppress hTERT expression at 200 nM concentration. It was also revealed that siRNA targeting hTERT could induce telomere attrition and then irreversible arrest of proliferation of cancer cells.

Biomarxism and the Problem of Individual Immortality

Biomarxism and the Problem of Individual Immortality

Suffering in the Epic of Gilgamesh

ABSTRACT This article examines moments of suffering in the Epic of Gilgamesh. Initially Gilgamesh himself causes much suffering by abusing his power as king and tormenting his subjects day and night. Enkidu is created to curb the king's energy and to alleviate the distress of the people. Gilgamesh's greatest joy in finding a true friend also turns into his greatest sorrow when Enkidu becomes ill and dies. Gilgamesh is inconsolable and his suffering drives him away from his palace and his city, in search of life everlasting. When a snake snatches away his last hope of living forever, he realises that life eternal is to be found in life here and now. The article concludes with some suggestions of appropriating Elizabeth Kubler Ross'five stages of grief to the Epic of Gilgamesh. Keywords: Gilgamesh, Enkidu, Uruk, Suffering, Trauma, Grief, Death

Revised

This paper details the design of rear upright for a JCU Tec-NQ (JTR) Racing Motorsport, Formula Society of Automotive Engineers (FSAE) race car using Aluminium Alloy 7075-T6 through the use of a track simulator developed by RMIT Racing, forces on the upright were calculated and an upright was designed in SolidWorks. To ensure optimal design with the aid of Finite Element Analysis using ANSYS workbench, three main load cases with combination of drive cases (acceleration, braking, and left and right turn) were used to evaluate performance of the rear upright. They include fatigue of upright, single bump loads and the zero-based fatigue loading of the calliper-mounting bracket. For the fatigue loading of the whole upright, it was observed that the greatest stress throughout the four drive cases occurred in a left hand turn. For single bump loads, the upright could withstand a vertical bump load of stress value significantly lower than the ultimate tensile strength. For the fatigue analysis on the brake calliper mount, the resulting safety factor plot presented a minimum factor of three for infinite life. Other relevant analysis were presented, such as sphere of influence and exaggerated deformation which showed that the upright will experience a maximum deformation of 0.132mm during the worst case lap scenario (left hand turn). The material considered for the design of the rear upright was Aluminium Alloy 7075-T6 as it has superior mechanical properties in terms of stiffness, fatigue and tensile strength for the application compared to both the Alumec alloy and Aluminium Alloy 6061-T6 considered in this paper.

Role of telomerase in the tumour microenvironment.

Telomeres are specialized genomic structures that protect chromosomal ends to maintain genomic stability. Telomeric length is primarily regulated by the telomerase complex, essentially consisting of an RNA template (TERC), an enzymatic subunit (telomerase reverse transcriptase, TERT). In humans, telomerase activity is repressed during embryonic differentiation and is absent in most somatic cells. However, it is upregulated or reactivated in 80%-90% of the primary tumours in humans. The human TERT (hTERT) plays a pivotal role in cellular immortality and tumourigenesis. However, the molecular mechanisms of telomerase functioning in cancer have not been fully understood beyond the telomere maintenance. Several research groups, including ours, have demonstrated that hTERT possesses vital functions independent of its telomere maintenance, including angiogenesis, inflammation, cancer cell stemness, and epithelial-mesenchymal transformation (EMT). All these telomere-independent activities of hTERT may contribute to the regulation of the dynamics and homeostasis of the tumour microenvironment (TME), thereby promoting tumour growth and development. Cancer progression and metastasis largely depend upon the interactions between cancer cells and their microenvironment. In this review, the involvement of TERT in the tumour microenvironment and the underlying implications in cancer therapeutics have been summarized.

Fatigue life prediction and reliability assessment of ductile iron castings using optimized mold design

Metal castings are often questioned for their service life and reliability due to a lot of uncertainties associated with the process. It is important to virtually analyze these aspects of a cast product before it actually put into service. This paper presents a new approach to predict the fatigue life and reliability of ductile iron castings through coupled simulations and experiments. In this work, fatigue specimens are considered as sample cast products which are produced using an optimized mold design for minimum porosity. Radiographic examination is done to observe the quality of cast specimens. Experimental load-controlled fatigue testing of selected specimens is done and compared with simulated fatigue lives in fe-safe (Dassault Systems UK Limited 2015). Reliability of cast specimens under fatigue is computed using stress-strength model by considering the variability in both stress and strength. A safe load-induced stress is estimated to obtain infinite life of ductile iron parts under consideration. Furthermore, the reliability models are developed by fitting probability distributions to reliability estimates and determining the distribution parameters. It is concluded that the mold design optimization using casting simulations can lead to nearly defect free castings which can serve for the similar fatigue lives as their sound counterparts. Moreover, the probability of survival of the cast components for an infinite life can be computed using the classical stress-strength reliability model based on which safe loading conditions can be determined for almost any engineering application.

Telomerase reverse transcriptase gene amplification in hematological malignancies

BackgroundTelomere is a complex DNA–protein structure located at the end of all eukaryotic chromosomes. The major role of human telomerase is to catalyze the addition of telomeric repeat sequences TTAGGG onto chromosome ends for stabilization of telomere length in attaining cellular immortality and may therefore be a critical step in carcinogenesis. Expression of significant levels of telomerase can dramatically increase proliferative life span and promote cellular immortality, thereby contributing to the malignant phenotype. The purpose of this study is to investigate telomerase reverse transcriptase (TERT) gene amplification in hematological neoplasms, e.g., multiple myeloma (MM), B-non-Hodgkin lymphoma (B-NHL), and acute myeloid leukemia (AML), using FISH technique and to evaluate its potential use as a prognostic marker.ResultsTERT amplification was detected in all groups of the participant patients (15 MM, 15 B-NHL, and 15 AML patients), with higher incidence in AML patients (53.3%). A significant association between the pattern of presentation and telomerase amplification was detected in 88.9% of the relapsed patients who demonstrated amplification of TERT. TERT amplification shows a significant association with p53 deletion and a highly significant association with poor prognosis.ConclusionsTERT gene amplification is significantly associated with hematological malignancies and may play a critical role in carcinogenesis; thus, elucidation of their regulatory mechanism is highly demanding. Higher amplification was found in relapsed cases than de novo cases which highlight its potential implication in clinical analysis and disease monitoring. Moreover, our results suggest the future use of TERT gene as a potential prognostic marker that may aid in treatment decision and chemotherapy.

Experimental study on wedge-bonded anchors for CFRP tendons under cyclic loading

This paper is concerned with an experimental study on a wedge-bonded anchor for carbon fibre reinforced polymer (CFRP) tendons under cyclic loading. The adhesive reinforced by quartz sand was tested to be superior as a bonding material for the anchor when compared to the adhesive reinforced by ferrous powder or aluminate powder. Structural responses of the wedge-bonded anchor under cyclic loading were analyzed with regard to system slip, sleeve strain, temperature rise in the anchor zone and residual tensile load capacity. The results indicate that the maximum stress level and stress ratio influence significantly the fatigue performance of wedge-bonded anchors. A cyclic loading with a high stress ratio and low stress level is beneficial due to the synergetic effect of the components in the wedge-bonded anchors. However, enhancing the stress level or lowering the stress ratio leads to a larger slip, greater damage and more loading cycles are needed for the stabilization of wedge-bonded anchors. When the stress ratio exceeds 0.4 and the maximum stress is less than 0.5, damage in anchor zone is initiated and developed in the early stage of cyclic loading, but the anchor becomes stable finally. A large decrease in stress ratio may result in a continuous development of microstructural damage and the eventual failure of the anchor, accompanied by continuously increasing energy dissipation under cyclic loading. The axial strain of sleeve in a wedge-bonded anchor is influenced by the extent of damage evolution and the synergetic effect of anchor assemblies; thereby resulting in different trends in sleeve strain-cycle curves under different stress ratios and stress levels. The temperature rise may be pronounced at a loading frequency of 10 Hz or less, which is related to the stress ratio. The damage development in the wedge-bonded anchor with an infinite fatigue life was analyzed. The mechanism of fatigue damage in wedge-bonded anchors is different from that of adhesively bonded anchors. Moreover, wedge-bonded anchors have a stronger resistance against fatigue due to the interaction between the wedges and the other assemblies.

CSIG-24. GABP LINKS AMPK SIGNALING TO TERT REGULATION IN A TERT PROMOTER MUTATION DEPENDENT MANNER

Abstract Over 90% of human tumors achieve immortality by reactivating telomerase reverse transcriptase (TERT), the catalytic subunit of telomerase. Two mutually exclusive, heterozygous mutations that activate the TERT promoter (TERTp) occur in a wide range of cancers including ~80% of glioblastomas (GBM). The mutations and TERTp activation enable cells to avoid replicative senescence and continue to divide beyond the normal limits on cellular lifespan, thus becoming immortal. Our lab has demonstrated that each mutation creates a novel E26-transformation specific binding site that allows the tetrameric form of the GA-binding protein GABP to bind and aberrantly activate the mutant TERTp. We further showed that reducing a tetramer-forming subunit of GABP, the GABPB1L transactivating subunit, reverses cellular immortality in vitro and reduces tumor growth in vivo. Beyond GABP, little is known about pathways that contribute to immortality via activation of the mutant TERTp. The heterotrimeric 5’ AMP-activated protein kinase (AMPK) complex is activated in human GBM compared to normal brain, and was previously implicated in regulating GABP expression. Here, we have determined that AMPK inhibition decreases transcription of both subunits of the tetrameric GABP complex (GABPA and GABPB1L) in GBM cells, and is sufficient to reduce TERT expression and telomerase activity in a TERT promoter mutation dependent manner. Together, these data suggest a novel and targetable connection between the AMPK signaling axis, telomerase activity and potentially tumor cell immortality.

Operating conditions leading to crack propagation in turbine blades of tidal barrages. Influence of head and operating mode

Tidal energy systems and specifically tidal barrages are renewable energy systems, that use the potential energy of tides to produce electricity. Actually, there are few tidal power stations operating, although recent studies show the potentiality of installing new units in a recent future due to the constant improvement of the technology related. As in other conventional hydropower systems, the runner is one of the critical components of the unit as it has to withstand an extreme wide range of relative head and two main operating modes (ebb and flood). Therefore, fatigue problems and undesirable failures are more likely to occur. Based on the analysis of a crack found in one of the blades of a prototype, this paper analyzes and discusses under which operating conditions the runner is more likely to suffer from fatigue problems. CFD and FEM simulation models have been used to determine the stress hotspots, which approximate very well the point where the real crack was initiated. Based on a probabilistic approach of an existing initial defect or flaw, the reliability of the blades, or the probability of not growing a crack and therefore last an infinite life, has been calculated for a wide range of operating conditions. While fatigue problems have been deeply discussed and analyzed in conventional turbines, the flow excitation characteristics in these units exhibit important differences and therefore the discussion and results provided in this paper could be useful for future designs and fatigue analyses of tidal turbines.

Telomere Length Maintenance and Its Transcriptional Regulation in Lynch Syndrome and Sporadic Colorectal Carcinoma.

Background: Activation of telomere maintenance mechanisms (TMMs) is a hallmark of most cancers, and is required to prevent genome instability and to establish cellular immortality through reconstitution of capping of chromosome ends. TMM depends on the cancer type. Comparative studies linking tumor biology and TMM have potential impact for evaluating cancer onset and development.Methods: We have studied alterations of telomere length, their sequence composition and transcriptional regulation in mismatch repair deficient colorectal cancers arising in Lynch syndrome (LS-CRC) and microsatellite instable (MSI) sporadic CRC (MSI s-CRC), and for comparison, in microsatellite stable (MSS) s-CRC and in benign colon mucosa. Our study applied bioinformatics analysis of whole genome DNA and RNA sequencing data and a pathway model to study telomere length alterations and the potential effect of the “classical” telomerase (TEL-) and alternative (ALT-) TMM using transcriptomic signatures.Results: We have found progressive decrease of mean telomere length in all cancer subtypes compared with reference systems. Our results support the view that telomere attrition is an early event in tumorigenesis. TMM gets activated in all tumors studied due to concerted overexpression of a large fraction of genes with direct relation to telomere function, where only a very small fraction of them showed recurrent mutations. TEL-related transcriptional state was dominating in all CRC subtypes, showing, however, subtype-specific activation patterns; while contribution of the ALT-TMM was slightly more prominent in the hypermutated MSI s-CRC and LS-CRC. TEL-TMM is mainly activated by over-expression of DKC1 and/or TERT genes and their interaction partners, where DKC1 is more prominent in MSS than in MSI s-CRC and can serve as a transcriptomic marker of TMM activity.Conclusions: Our results suggest that transcriptional patterns are indicative for TMM pathway activation with subtle differences between TEL and ALT mechanisms in a CRC subtype-specific fashion. Sequencing data potentially provide a suited measure to study alterations of telomere length and of underlying transcriptional regulation. Further studies are needed to improve this method.

Low-cost, monolithically 3D-printed, miniature high-flow rate liquid pump

We report the design, fabrication, and characterization of the first monolithically 3D-printed, high-flow rate miniature liquid pumps in the literature. Our low-cost, leak-tight, miniature devices are microfabricated using 150 to 300 μm layers in pure Nylon 12 via fused filament fabrication with a multi-step printing process that monolithically creates all key features with <13 μm in-plane misalignment. Each pump has a rigid frame, a 21 mm-diameter, 150 μm-thick membrane connected at its center to a piston with an embedded magnet, a chamber, passive ball valves, and two barbed fluidic connectors. Pump fabrication under 2 hours and costs less than $4.65 (about $0.65 in printable feedstock). Finite element analysis of the actuator predicts a maximum stress of 18.7 MPa @ 2 mm deflection, i.e., about the fatigue limit of Nylon 12 for infinite life (i.e., 19 MPa). A maximum water flow rate of 1.37 ml/min at 15.1 Hz actuation frequency is calculated –comparable to reported values of miniature liquid pumps with up to two orders of magnitude higher actuation frequency.

Human telomerase reverse transcriptase and cutaneous malignant tumor

Human telomerase reverse transcriptase (hTERT) is a catalytic subunit of telomerase and is closely related to immortalization of cells, tumorigenesis and senescence of cells. hTERT has a great relationship with the occurrence and development of skin malignant tumors (melanoma, squamous cell carcinoma, basal cell carcinoma, cutaneous lymphoma, etc.). Abnormal expression of hTERT has important clinical application value in early diagnosis, individualized comprehensive treatment and prognosis evaluation of cutaneous malignant tumors. Key words: Telomere; Skin neoplasms; Genes; Human telomerase reverse transcriptase

Design optimizations of PLA stent structure by FEM and investigating its function in a simulated plaque artery

Proper design and optimization in stent parameters are required for efficient use of stents in coronary arteries. Efficiency depends on features including resistance against vessel pressures, (Radial Strength) limited variation in length during expansion (Foreshortening & Recoil) and resistance of stents in periodic/cyclic pressure & tension of heart pulsation (Fatigue Life Cycle). It is customary to design a stent based upon materials endurance limit which is equivalent to 0.5 of the yield strength for stainless steel in order to accomplish physically infinite life cycle for the stent.Different atherosclerosis removal rates are reported by various stent designs. Hence, considering the significance of designs and costly classic methods of producing prototypes, using finite element analysis is beneficial due to the high efficiency and accuracy as well as lower costs. In this study a biocompatible polymeric stent (PLA) is designed by SolidWorks software and influence of designing parameters including longitudinal pattern (Cell) number, circular–circumferential pattern (Cell) number, connection of cells by N, M, or W type flex connector, radius curve, thickness, maximum and minimum width on the mechanical properties such as contact force, foreshortening and maximum stress are estimated by FEM on over 58000 models. The effective design parameters are subsequently optimized to obtain the best model for the stent. Performance of the optimized stent is then investigated in a simulated artery suffering from a 49% non-uniform plaque and after the implementation of the stent in the artery, the inner area of the cross section of the artery increased by 74 percent which demonstrates improvement in blood flow by 74 percent. Results can be useful in designing and optimizing stents for non-uniform restenosis conditions.

Numerical analysis of vhcf cruciform test specimens with non-unitary biaxiality ratios

With the development of new materials, it is now known that there is no such thing as a fatigue endurance limit, i.e., materials do not have infinite life when the stress level is such that there is no fracture up to 10 million (1E7) cycles. The problem of testing materials above this number of cycles is that most testing equipment operates well below 150 Hz, making testing up to 1 billion (1E9) cycles or above an impracticality. The recent developments of ultrasonic testing machines where frequencies can go as high as 20 kHz or above enabled tests to be extended to these ranges in just a few days. This is now known as Very High Cycle Fatigue (VHCF). On the other hand, critical components used in Engineering applications are usually subjected to multi-axial loads, as is the case of the fuselage and wings of aircrafts which are subjected to biaxial states of stress. In this paper, VHCF cruciform test specimens purposely designed to develop orthogonal biaxial stresses with different biaxiality ratios will be analysed. The specimens are composed from Aluminium 6082-T651, a medium strength alloy used in many highly stressed engineering applications, including trusses, cranes, bridges and transportation. The specimens work as tuning forks with determined mode shapes at 20±0.5 kHz, where maximum principal stresses are developed at the centre of the specimen. Finite Element Analysis (FEA) is used to assess the dynamic behaviour of the specimens. The framework on how to design and manufacture cruciform specimens with different biaxiality ratios will be explained in a clear way so it can be used by other engineers in the field.

Life Model Enhancement for Hybrid Ball Bearings

Based on experimental life data on silicon nitride balls, the stress-life exponent and life constant in the generalized ball life equation, developed earlier, are modified to better simulate the fatigue life of silicon nitride balls in hybrid ball bearings. The modified ball life equation is then integrated with generalized life equations for the outer and inner races to model the life of a complete hybrid ball bearing. It is found that in view of the relatively high stress-life exponent for silicon nitride balls, computation of hybrid bearing life with infinite ball life may not be unreasonable. Model predictions are in good agreement with limited available experimental life data on hybrid ball bearings.

Assessment of the Carbon and Cost Savings of a Combined Diesel Generator, Solar Photovoltaic, and Flywheel Energy Storage Islanded Grid System

The use of diesel generators to provide power for islanded grids has been the technology of choice but they generate substantial carbon emissions unless the part or all the fuel comes from a renewable source. Notwithstanding this, the engine must be sized to meet maximum demand and will operate inefficiently at part load most of the time, which is particularly bad for a synchronous constant speed engine. Given the availability of low cost solar photovoltaic (PV) systems, it is very enticing to fit a diesel generator and allow the engine to be turned off during PV generation. However, this combination will not work without some form of energy storage since it takes time for the engine to start, leading to gaps in supply and instability of the system. Lithium-ion batteries are typically considered to be the best solution to this problem because they have a high response rate, costs are lower, and they are available as products. However, they will suffer from the limited cycle and calendar life due to high cycling requirements in the application described. It is, therefore, proposed that a flywheel system could offer a lower lifetime cost alternative since only short duration bridging power storage is needed and flywheels of appropriate design can offer lower power cost than Lithium-ion battery systems. Flywheels are particularly attractive since they have a very high calendar with almost an infinite cycle life and are fully recyclable at the end of life. This research, therefore, presents an assessment of the flywheel energy storage system (FESS) as an alternative to electrochemical batteries to supplement solar PV systems backed up by diesel generators. The model of an islanded PV system combined with a diesel generator and a FESS supplying power to a residential load is implemented in MATLAB/Simulink. The results of the analysis for the cases with and without storage based on a number of different charge-discharge strategies provide evidence to support this hypothesis.

PITX1 protein interacts with ZCCHC10 to regulate hTERT mRNA transcription.

Telomerase is a ribonucleoprotein ribonucleic enzyme that is essential for cellular immortalization via elongation of telomere repeat sequences at the end of chromosomes. Human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase holoenzyme, is a key regulator of telomerase activity. Telomerase activity, which has been detected in the majority of cancer cells, is accompanied by hTERT expression, suggesting that this enzyme activity contributes to an unlimited replication potential of cancer cells via regulation of telomere length. Thus, hTERT is an attractive target for cancer-specific treatments. We previously reported that pared-like homeodomain 1 (PITX1) is a negative regulator of hTERT through direct binding to the hTERT promoter. However, the mechanism by which the function of PITX1 contributes to transcriptional silencing of the hTERT gene remains to be clarified. Here, we show that PITX1 and zinc finger CCHC-type containing 10 (ZCCHC10) proteins cooperate to facilitate the transcriptional regulation of the hTERT gene by functional studies via FLAG pull-down assay. Co-expression of PITX1 and ZCCHC10 resulted in inhibition of hTERT transcription, in melanoma cell lines, whereas mutate-deletion of homeodomain in PITX1 that interact with ZCCHC10 did not induce similar phenotypes. In addition, ZCCHC10 expression levels showed marked decrease in the majority of melanoma cell lines and tissues. Taken together, these results suggest that ZCCHC10-PITX1 complex is the functional unit that suppresses hTERT transcription, and may play a crucial role as a novel tumor suppressor complex.

Long telomeres and cancer risk: the price of cellular immortality

The distribution of telomere length in humans is broad, but it has finite upper and lower boundaries. Growing evidence shows that there are disease processes that are caused by both short and long telomere length extremes. The genetic basis of these short and long telomere syndromes may be linked to mutations in the same genes, such as the telomerase reverse transcriptase (TERT), but through differential effects on telomere length. Short telomere syndromes have a predominant degenerative phenotype marked by organ failure that most commonly manifests as pulmonary fibrosis and are associated with a relatively low cancer incidence. In contrast, insights from studies of cancer-prone families as well as genome-wide association studies (GWAS) have identified both rare and common variants that lengthen telomeres as being strongly associated with cancer risk. We have hypothesized that these cancers represent a long telomere syndrome that is associated with a high penetrance of cutaneous melanoma and chronic lymphocytic leukemia. In this Review, we will synthesize the clinical and human genetic observations with data from mouse models to define the role of telomeres in cancer etiology and biology.