The actin cytoskeleton is substantially modified in cancer cells because of changes in actin-binding protein abundance and functional activity. As a consequence, cancer cells have distinctive ...motility and mechanical properties, which are important for many processes, including invasion and metastasis. Here, we studied the effects of actin cytoskeleton alterations induced by specific nucleation inhibitors (SMIFH2, CK-666), cytochalasin D, Y-27632 and detachment from the surface by trypsinization on the mechanical properties of normal Vero and prostate cancer cell line DU145. The Young's modulus of Vero cells was 1300±900Pa, while the prostate cancer cell line DU145 exhibited significantly lower Young's moduli (600±400Pa). The Young's moduli exhibited a log-normal distribution for both cell lines. Unlike normal cells, cancer cells demonstrated diverse viscoelastic behavior and different responses to actin cytoskeleton reorganization. They were more resistant to specific formin-dependent nucleation inhibition, and reinforced their cortical actin after detachment from the substrate. This article is part of a Special Issue entitled: Mechanobiology.
•Cancer DU145 cells demonstrate different viscoelastic properties than normal Vero cells.•Targeted actin cytoskeleton reorganization leads to a different mechanical response of malignant and normal cells.•The different response to actin cytoskeleton reorganization might be a diagnostic marker for cancer cells.•Data indicate that cortical actin plays a significant role in cancer cell mechanics.
The viscoelastic parameters of the cell can report on the cell state, cellular processes and diseases. Cell mechanics strongly rely on the properties of the cytoskeleton, an important system of ...subcellular filaments, especially on the high-level structures that actin forms together with actin-binding proteins (ABPs). In normal cells, components of the cytoskeleton are highly integrated, and their functions are well orchestrated. In contrast, impaired expression and functioning of ABPs lead to the increasing ability of cancer cells to resist chemotherapy and metastasize. ABP-mediated changes in the cytoskeleton architecture can lead to changes in the mechanical properties of the actin network, both locally and at the level of the whole cell. Until now, in cancer-related studies, mechanical data have been used less frequently, compared to biochemical tests or cell migration assays. Here, we will review current methods for analyzing the mechanical properties of cells and provide the available data on the contribution of ABPs in determining cell mechanical properties important for the investigation of cellular functions, particularly in cancers.
•The cytoskeleton architecture controls the mechanical properties of the cell.•Actin-binding proteins affect cell mechanical properties via cytoskeleton modifications.•Different actin-binding proteins may have opposite effects on cell stiffness.•Small-molecule inhibitors of ABPs become a common tool for mechanobiology studies.
This paper presents algorithms for several “passive” and “active” means of pilot-induced oscillations suppression developed by Moscow Aviation Institute (MAI). By conducting experimental studies ...using a ground-based simulator, the effectiveness of using these means in suppressing the pilot-induced oscillations is assessed. The integration of “passive” and “active” means is considered.
Primary hyperparathyroidism (PHPT) is a common endocrine disorder caused by a parathyroid tumor or hyperplasia, which is often accompanied with quality of life (QoL) impairment. A parathyroidectomy ...(PTX) is the preferred standard treatment for PHPT patients. In this single center study we aimed to evaluate the impact of PHPT on patient's QoL and identify QoL changes at early and long-term follow-up after surgery.
All the patients underwent routine PTX with the removal of the suspected hyperparathyroid gland(s). Patients filled out generic QoL questionnaire RAND SF-36, specific questionnaire PHPQoL and specific symptom assessment questionnaire PAS upon admission to the hospital before surgery, at 3 months, 12 months and 24 months after surgery.
A total of 92 patients with PHPT (median age was 56 years, 95.7% females) were included in the study. Before PTX patient's QoL by SF-36 scores was significantly lower as compared to healthy controls (p < 0.01). Almost 40% of patients had poor or very poor QoL. The most frequent symptoms by PAS before surgery were as follows: tiredness (97.8% of patients), weakness (94.6%), forgetfulness (94.6%), mood changes (90%), feeling "blue"/depression (88%), joint pains (83.3%), headaches (80.2%), constant irritability (77.2%), bone pains (75%), thirst (70.7%) and trouble getting out of a chair (67.4%). The half of the patients had moderate-to-severe (≥ 40 scores) tiredness, weakness, joint pains, forgetfulness, as well as mood changes. Post-operative QoL changes were analysed in the group of 72 patients. After surgery there was significant improvement in QoL by all scales of SF-36 questionnaire, excluding bodily pain, and the PHPQoL total score (GEE, p < 0.01) as compared with their values before surgery. Also severity of tiredness, mood changes, weakness and forgetfulness significantly decreased after surgery as compared to their baseline values (GEE, p < 0.05). Decreased mental component of QoL by PHPQoL (OR = 0.927, 95%CI = 0.874-0.984, p = 0.013) predicted improved QoL after surgery.
Patients with PHPT demonstrated significantly impaired QoL in physical, psychological and social functioning as well experienced a wide profile of common PHPT symptoms. Successful PTX was accompanied with remarkable QoL improvement and decrease in subjective symptoms for at least 24 months after surgery.
A
bstract
We present the complete cross-section for the production of unpolarized hadrons in semi-inclusive deep-inelastic scattering up to power-suppressed
O
1
/
Q
2
terms in the ...Wandzura-Wilczek-type approximation, which consists in systematically assuming that
q
¯
g
q
-terms are much smaller than
q
¯
q
-correlators. We compute all twist-2 and twist-3 structure functions and the corresponding asymmetries, and discuss the applicability of the Wandzura-Wilczek-type approximations on the basis of available data. We make predictions that can be tested by data from COMPASS, HERMES, Jefferson Lab, and the future Electron-Ion Collider. The results of this paper can be readily used for phenomenology and for event generators, and will help to improve the description of semi-inclusive deep-inelastic processes in terms of transverse momentum dependent parton distribution functions and fragmentation functions beyond the leading twist.
An approximate expression of the power, which depends on the characteristics of the pilot–aircraft system, is given. It is shown that the power values for different dynamic configurations correlate ...with the level of flying qualities, making it possible to use it as a criterion for assessing the flying qualities.
The application of inverse dynamics for the improvement of flying qualities is considered. It is shown that the use of the inverse dynamics in the control loop suppresses the dynamics of the aircraft ...considerably, leaving only the dynamics of the integral in almost the entire frequency range. The inverse dynamics however could not help in case of atmospheric disturbances or modeling uncertainties. A new scheme using a reference model and its inverse was presented to counter these effects. The results of the mathematical modeling showed that the inverse dynamics allow to improve the tracking performances and all other parameters of the pilot-aircraft system compared to the controller synthesized with feedback gains only. These results were confirmed using ground based simulation. These simulations showed that the use of the inverse dynamics based technique allowed to decrease the variance of error up to 60% during a tracking compensation task. The simulations also showed to that the addition of the reference model and its inverse proved to be able to reduce or suppress atmospheric turbulence, couplings between different control channels and effects of modeling uncertainties, while improving the tracking accuracy and decreasing the pilot workload, thus enhancing the flying qualities of the helicopter.
Solanum tuberosum
L. is the most important non-grain starch crop with a potential yield of 38–48 t/ha and a starch content of 13.2–18.7 %. Potato tubers are stored at a low temperature (2–4 °C) in a ...state of physiological dormancy. A disadvantage of this type of storage is the degradation of starch and the accumulation of reducing sugars (cold-induced sweetening), including due to an increase in the activity of β-amylases that hydrolyze starch to maltose. In this study, a comparative analysis of the β-amylase (
StBAM1, StBAM9
) and amylase inhibitor (
StAI
) gene expression, as well as starch and reducing sugar content in tubers during long-term low-temperature storage (September, February, April) was performed using potato cultivars Nadezhda, Barin, Krasavchik, Severnoe siyanie and Utro. The β-amylase genes,
StBAM9
and one of the two
StBAM1
homologs (with the highest degree of homology with
AtBAM1
), were selected based on phylogenetic analysis data. Evaluation of the expression of these genes and the amylase inhibitor gene showed a tendency to decrease in transcription for all analyzed cultivars. The starch content also significantly decreased during tuber storage. The amount of reducing sugars increased in the September–April period, while in February–April, their content did not change (Krasavchik), decreased (Barin, Severnoe siyanie) or continued to grow (Utro, Nadezhda). It can be assumed that the gene activity of
StBAM1
and
StBAM9
correlates with the amount of starch (positively) and monosaccharides (negatively). The level of StAI expression, in turn, may be directly dependent on the level of
StBAM1
expression. At the same time, there is no relationship between the degree of cultivar predisposition to cold-induced sweetening and the expression profile of the
StBAM1
,
StBAM9
, and
StAI
genes.
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