Combined Radiation Effects Research Articles

Unsteady MHD viscous dissipative Kuvshinski fluid past an infinite vertical porous plate with radiation, Soret, and Joule heating effect

AbstractThis paper scrutinizes the combined effect of radiation, Soret, Joule heating, and chemical reaction on an unsteady magnetohydrodynamic visco‐elastic (Kuvshiniski type) fluid flow over an infinite vertical moving plate. The viscous dissipation, heat source, thermal and solutal buoyancy forces are taken into account. The plate is assumed to be embedded in a porous media and a transverse magnetic field is applied to the stream. The nondimensional governing equations are solved analytically using perturbation techniques. The influences of various dimensionless parameters on fluid velocity, temperature and concentration profiles, as well as the skin‐friction, Nusselt number and Sherwood number are analyzed and discussed graphically. Also, the present results are compared with previous studies and is found to be in excellent agreement. It has been shown that rising Soret numbers cause velocity, temperature and concentration to rise. Further, a hike in visco‐elastic parameter leads to decrease in motion, temperature and concentration profile.

Combined radiation and chemotherapy versus monotherapy for anaplastic thyroid cancer: A SEER retrospective analysis

BackgroundThe effect of combined radiation and chemotherapy (combination therapy) versus monotherapy on anaplastic thyroid carcinoma (ATC) has not yet been clear. MethodsWe identified 516 ATC patients during 2010–2015 from the Surveillance, Epidemiology and End Results (SEER) database and evaluated their survival outcome using the Kaplan-Meier method, Cox regression analysis and propensity score matching (PSM) technique. ResultsThe median overall survival (OS) among the entire cohort was 3 months (95 % confidence interval [CI], 2.58–3.42 months), and the 6- and 12-month OS rates were 29 % (95 % CI, 25.01%–32.88 %) and 13 % (95 % CI, 10.60%–16.58 %), respectively. Multivariable analysis demonstrated that ATC patients not receiving radiotherapy or chemotherapy were unquestionably associated with worse OS (hazard ratio [HR] 3.000, 95 % CI, 2.390–3.764) and cancer-specific survival (CSS) (HR = 3.107, 95 % CI, 2.388–4.043), compared with those receiving combination therapy. However, combination therapy did not predict better prognosis compared with monotherapy (all P > 0.05). After PSM, the median OS and CSS were also not significantly improved in patients undergoing chemoradiotherapy versus chemotherapy alone (OS, P = 0.382; CSS, P = 0.420) or radiotherapy alone (OS, P = 0.065; CSS, P = 0.251). ConclusionCombination therapy, compared to monotherapy, does not have the expected improvement in survival beyond the benefits achievable with each single-modality treatment, necessitating further prospective research to tailor its treatment management.

Radiation pressure and galactic cosmic rays-driven gravitational instability in rotating and magnetized viscoelastic fluids

This paper studies the combined effects of radiation and galactic cosmic ray pressures on the gravitational instability of magnetized and rotating viscoelastic fluids. The dispersion relations are derived using the normal mode analysis and discussed in the hydrodynamic (weakly coupled fluid) and kinetic (strongly coupled fluid) limits. These dispersion relations are analyzed separately for transverse and longitudinal wave propagation modes. Jeans instability criteria are obtained for kinetic and hydrodynamic limits for both modes of wave propagation, and it is found that the critical Jeans wavenumbers in each case are modified due to the presence of viscoelastic effects, radiation and cosmic rays pressures, and Alfvên wave velocity. It is also observed that the radiation pressure, cosmic ray pressure and viscoelastic parameters suppress the growth rate and thus have stabilizing effects on the Jeans instability. However, cosmic ray diffusion has a destabilizing effect on the onset of gravitational instability. The effects of various parameters on the growth rate of instability are calculated numerically and the outcomes are depicted graphically. The results of the present analysis shall be helpful in understanding the impact of cosmic rays and radiative mechanisms on the gravitational collapse in the viscoelastic region of molecular cloud clumps.

Combined effects of radiation and simulated microgravity on intestinal tumorigenesis in C3B6F1 ApcMin/+ mice

Explorations of the Moon and Mars are planned as future manned space missions, during which humans will be exposed to both radiation and microgravity. We do not, however, know the health effects for such combined exposures. In a ground-based experiment, we evaluated the combined effects of radiation and simulated microgravity on tumorigenesis by performing X-irradiation and tail suspension in C3B6F1 ApcMin/+ mice, a well-established model for intestinal tumorigenesis. Mice were irradiated at 2 weeks of age and underwent tail suspension for 3 or 11 weeks using a special device that avoids damage to the tail. The tail suspension treatment significantly reduced the thymus weight after 3 weeks but not 11 weeks, suggesting a transient stress response. The combination of irradiation and tail suspension significantly increased the number of small intestinal tumors less than 2 mm in diameter as compared with either treatment alone. The combined treatment also increased the fraction of malignant tumors among all small intestinal tumors as compared with the radiation-only treatment. Thus, the C3B6F1 ApcMin/+ mouse is a useful model for assessing cancer risk in a simulated space environment, in which simulated microgravity accelerates tumor progression when combined with radiation exposure.

Unveiling the Behavior of MHD Mixed Convective Nanofluid Slip Flow over a Moving Vertical Plate with Radiation, Chemical Reaction, and Viscous Dissipation

The effects of chemical reactions on heat and mass transfer with radiation are extremely important in hydrometallurgical industries and chemical technology, such as polymer synthesis and food processing. A mathematical model for a viscous, incompressible, mixed convective, and MHD slip flow over a moving vertical plate is proposed in the present research. On account of physical relevance, the combined effect of radiation and chemical reaction on MHD nanofluid is studied. Using the similarity transformation method, the governing equations are converted into a system of ODEs. The transformed equations are then numerically solved by the Galerkin finite element method (GFEM). To analyse the characteristics of flow and heat transfer, a number of parameters are examined, including the slip, magnetic, radiation, and chemical reaction parameters, as well as the Schmidt, Grashof, Eckert, and Prandtl numbers. The coefficient of skin friction, Nusselt number, and Sherwood numbers for selected parameters are numerically presented. Graphs are used to determine and study the effects of magnetic fields, slip conditions, radiation, and chemical reactions on the temperature, concentration, and velocity profiles of nanofluids. This study shows that the presence of chemical reactions and radiation causes an increase in the velocity profile and temperature profile, respectively. Additionally, it is discovered that the temperature profile grows with increasing velocity slip, and concentration increases with increasing thermal slip. The current work has broad applications in various fields and can lead to the development of more efficient and effective systems in different industries, such as heat exchangers, energy production, environmental engineering, and biomedical engineering.

Numerical investigation of combined effects of radiation and convection heat transfer from tube banks placed in a participating medium

In the present study, combined convective and radiative heat transfer from in-line tube banks placed in an absorbing, emitting and isotropically scattering participating medium was numerically investigated. The governing flow and radiative transfer equations were solved numerically by utilizing the finite volume methodology and the P1 approximation. The flow is laminar, and the tube walls are black and isothermal. The parameters affecting the heat transfer in such media are the tube pitch, scattering albedo, Reynolds number and conduction-to-radiation parameter. Numerical simulations were carried out for Reynolds numbers between 100 and 300, and the transversal and longitudinal pitches ranging from 1.5D to 3-D, respectively. Also, the medium related parameters such as scattering albedo and conduction-to-radiation parameter were ranged between 0 to 1 and 0.0367 to 0.5080, respectively. The effects of the change in scattering albedo, conduction-to-radiation parameter as well as flow characteristic and tube pitch on temperature distribution and heat transfer were examined. The convective and radiative heat transfer from tubes is analyzed via the surface averaged mean Nusselt number over the whole tube wall. The lowest and the highest total-radiative Nusselt number values were achieved as 3.66-0.091 in the purely scattering medium and as 32.95-25.14 in the non-scattering medium, respectively. Also, a novel correlation (with a coefficient of determination of 0.99804) for tube banks subjected to convection and radiation in a participating media was developed.

Irradiation of Multimode Ge-doped and F-doped Optical Fibers at Cryogenic Temperatures Down to 10 K

The combined effect of radiation and cryogenic temperatures on the response of two different multimode fibers (MMF), one conventional and one radiation resistant, has been investigated. This article presents the outcome of the measurements of the radiation induced attenuation (RIA) in those fibers at 830 nm and 1310 nm under gamma irradiation and at temperatures of 300 K, 218 K, 143 K and 10. The results reveal a strong increase of the RIA when decreasing the temperature down to cryogenic levels, with substantial different growth dynamics between the two fibers. However, both cases show a non-linear dependence of the RIA on the temperature. It is also observed that after a long recovery time, including the heating of the fiber from cryogenic temperature to room temperature, a large amount of the defects created are annealed, bringing the radiation resistant fiber close to its initial performance.

Radiation combined with KRAS-MEK inhibitors enhances anticancer immunity in KRAS-mutated tumor models

KRAS mutation is a common driver in solid tumors, and KRAS-mutated tumors are relatively resistant to radiotherapy. Therefore, we investigated the combined effect of radiation and KRAS-MEK inhibitors (AMG510 and trametinib) in KRAS-mutated tumors. The expression of programmed death-ligand 1 (PD-L1), major histocompatibility complex (MHC) class I molecules, and cytokines in KRAS-mutated cell lines was assessed using flow cytometry, western blot analysis, quantitative polymerase chain reaction, and enzyme-linked immunosorbent assay. In vivo, tumor growth, T cell infiltration, and gene sequencing analyses were conducted in 2 murine KRAS-mutated models. Both AMG510 and trametinib decreased the radiation-induced increase in PD-L1 expression. Radiation and trametinib additively induced the expression of CXCL10 and CXCL11 cytokines and MHC class I in murine CT26 and LLC cell lines. The combination of trametinib and radiation controlled tumor growth and induced more infiltration of CD4+ and CD8+ T cells in vivo, wherein tumor inhibition function and the survival period of mice could be reduced by CD8+ and/or CD4+ T cell depletion. The expression levels of immune-related genes also increased in the combination therapy group. Our results indicate that KRAS-MEK inhibitors in combination with radiotherapy can enhance antitumor immunity, providing new therapeutic strategies for KRAS-mutated tumors.

Potential of Gold Nanoparticle in Current Radiotherapy Using a Co-Culture Model of Cancer Cells and Cancer Associated Fibroblast Cells.

Many cancer therapeutics are tested in vitro using only tumour cells. However, the tumour promoting effect of cancer associated fibroblasts (CAFs) within the tumour microenvironment (TME) is thought to reduce cancer therapeutics' efficacy. We have chosen pancreatic ductal adenocarcinoma (PDAC) as our tumor model. Our goal is to create a co-culture of CAFs and tumour cells to model the interaction between cancer and stromal cells in the TME and allow for better testing of therapeutic combinations. To test the proposed co-culture model, a gold nanoparticle (GNP) mediated-radiation response was used. Cells were grown in co-culture with different ratios of CAFs to cancer cells. MIA PaCa-2 was used as our PDAC cancer cell line. Co-cultured cells were treated with 2 Gy of radiation following GNP incubation. DNA damage and cell proliferation were examined to assess the combined effect of radiation and GNPs. Cancer cells in co-culture exhibited up to a 23% decrease in DNA double strand breaks (DSB) and up to a 35% increase in proliferation compared to monocultures. GNP/Radiotherapy (RT) induced up to a 25% increase in DNA DSBs and up to a 15% decrease in proliferation compared to RT alone in both monocultured and co-cultured cells. The observed resistance in the co-culture system may be attributed to the role of CAFs in supporting cancer cells. Moreover, we were able to reduce the activity of CAFs using GNPs during radiation treatment. Indeed, CAFs internalize a significantly higher number of GNPs, which may have led to the reduction in their activity. One reason experimental therapeutics fail in clinical trials relates to limitations in the pre-clinical models that lack a true representation of the TME. We have demonstrated a co-culture platform to test GNP/RT in a clinically relevant environment.

Immune System Response after Immobilization Stress in the Background of Ionizing Radiation

We studied the combined effect of gamma radiation (6 Gy, remote period) and immobilization stress on immunological reactivity. Materials and methods. To address this, we carried out experiments on 40 white male Wistar rats weighing 220 ± 20 g, which were divided into 4 groups: Group I - intact animals, group II - animals exposed to gamma radiation (dose of 6 Gy), group III - animals exposed to immobilization stress and group IV - animals exposed to combined exposure to gamma radiation (dose of 6 Gy) and immobilization stress. Animals in groups II and IV were irradiated 90 days before the study on the TERAGAM radiotherapeutic cobalt unit. In groups III and IV, animals were modeled for acute immobilization stress by immobilization for 6 h in bright light. Results. At the early period of immobilization stress, all indicators of the immune system, such as cellular, humoral and nonspecific phagocytic links of immunity were activated, indicating the activation of the general adaptive syndrome of the organism. The suppressive action of gamma radiation on the immune system was preserved in a remote period, with this suppression being revealed not only on the T-cellular link, but also on nonspecific phagocytic links, and the functional metabolic activity of neutrophils. In the remote period after the combined effect of sublethal gamma radiation and immobilization stress in the early stage of the adaptation syndrome, there was a decrease in all cells of the T system of immunity, in the functional ability of leukocytes, and in the mononuclear phagocytic system of the body. The experimental immobilization-radiation pathological process was accompanied by disorders of the functional activity of the essential adaptive systems of the body. Based on our results, we could conclude about the dominant role of ionizing radiation in immunological reactivity.
 HIGHLIGHTS
 
 At an early stage, after exposure to stress, the general adaptation syndrome is activated in the body
 The suppressive effect of gamma radiation on the immune status and phagocytic activity persists in the long term
 The pathological process that occurs under the combined effects of radiation and immobilization stress is accompanied by a violation of the functional activity of the most important adaptive systems of the body
 Under the combined influence of radiation and non-radiation factors, the radiation factor has a predominant influence
 
 GRAPHICAL ABSTRACT

Effects of Concurrent Chemoradiotherapy on the Metastasis and the Mesenchymal Transition of Bladder Urothelial Carcinoma Cells.

Cancer stem cells (CSCs) have been suggested playing a crucial role in the tumorigenesis and tumor progression. Clinically, concurrent chemoradiotherapy (CCRT) after transurethral resection of the bladder is the widely accepted treatment option for high-grade bladder urothelial carcinoma (UC); however, a proportion of bladder UC patients still suffer from recurrence and metastasis. In the present study, we investigated the stemness properties of bladder UC cells with respect to various disease stages. The metastatic capability and epithelial-mesenchymal transition (EMT) of the parental cells and the CSC cells of bladder UC, after chemotherapy with cisplatin alone or CCRT were also studied, respectively. The aldehyde dehydrogenase (ALDH)-positive cells were analyzed by a flow cytometer. The inhibitory effects of radiation in combination with cisplatin on the cell viability, migration, invasion and EMT characteristics were also examined. We found that the proportion of ALDH+-CSCs of bladder UC cells and the disease grading were independent. Furthermore, cisplatin alone significantly (p<0.05) enhanced the migration of both grade-III T24 cells and advanced-stage HT1197 cells, while CCRT treatment significantly (p<0.05) inhibited the T24 cell migration capability, compared to the cisplatin alone group. Interestingly, we found that the cell invasion capability was obviously increased upon the treatment with CCRT in both T24 and HT1197 CSCs. Furthermore, cisplatin played a promoting role in EMT whether in the presence or absence of irradiation. CSCs as well as EMT signaling might contribute to the resistance and metastasis of one-shot CCRT in malignant bladder cancer.

Effects of a combined treatment regimen consisting of Hsp90 inhibitor DS-2248 and radiation in vitro and in a tumor mouse model

BackgroundHeat shock protein 90 (HSP90) is a molecular chaperone that is responsible for the conformational maintenance of several client proteins that play important roles in DNA damage repair, apoptosis following radiation, and resistance to radiation therapy. DS-2248 (tricyclic pyrazolopyrimidine derivative) is a newly-developed, orally available inhibitor of HSP90 with low adverse effects. We investigated the combined effects of radiation and DS-2248 in vitro and in vivo.MethodsSCCVII squamous cell carcinoma cells and tumors transplanted in C3H/HeN mice were used. In vitro combined effects of X-ray radiation and DS-2248 were investigated using a colony assay. Phosphorylated histone H2AX (γH2AX) was quantified after 2-Gy irradiation with or without 24-hour pretreatment with DS-2248. The mice bearing SCCVII tumors received oral DS-2248 10 times over 2 weeks and received local irradiation with doses of 1, 2, 3, and 4 Gy delivered 6 times over 2 weeks. Then, tumor volumes were measured.ResultsRadiation plus pretreatment with 50 nM DS-2248 for 24 hours produced synergistic effects on SCCVII cells. γH2AX foci persisted after radiation for longer periods (6 and 24 hours) in DS-2248-treated cells than in control cells. In vivo, the combined effects appeared to be additive when 5 or 10 mg/kg DS-2248 was combined with total radiation doses of 6–18 Gy, but the effect was considered supra-additive when 15 mg/kg of DS-2248 was combined with a total dose of 24 Gy.ConclusionsThe combined effects of DS-2248 and radiation were additive at low drug and radiation doses, but may have been supra-additive at higher doses. Inhibition of slow repair of DNA double strand breaks (i.e., homologous recombination) was considered to contribute to this combined effect.

The individual and combined effects of spaceflight radiation and microgravity on biologic systems and functional outcomes

Both microgravity and radiation exposure in the spaceflight environment have been identified as hazards to astronaut health and performance. Substantial study has been focused on understanding the biology and risks associated with prolonged exposure to microgravity, and the hazards presented by radiation from galactic cosmic rays (GCR) and solar particle events (SPEs) outside of low earth orbit (LEO). To date, the majority of the ground-based analogues (e.g., rodent or cell culture studies) that investigate the biology of and risks associated with spaceflight hazards will focus on an individual hazard in isolation. However, astronauts will face these challenges simultaneously Combined hazard studies are necessary for understanding the risks astronauts face as they travel outside of LEO, and are also critical for countermeasure development. The focus of this review is to describe biologic and functional outcomes from ground-based analogue models for microgravity and radiation, specifically highlighting the combined effects of radiation and reduced weight-bearing from rodent ground-based tail suspension via hind limb unloading (HLU) and partial weight-bearing (PWB) models, although in vitro and spaceflight results are discussed as appropriate. The review focuses on the skeletal, ocular, central nervous system (CNS), cardiovascular, and stem cells responses.

Evaluation of Lipid Peroxidation under Immobilization Stress in Irradiated Animals in Experiment

BACKGROUND: For many years, the world community has been concerned with the problem of the consequences of radiation exposure on the human body. A wide range of possible variants of radiation effects on humans and biota determines the range of necessary pharmacological means of protecting the organism and populations. In the mechanisms of the formation of radioresistance, the leading role is assigned to the processes of lipid peroxidation (LPO) and the antioxidant (AO) system. The study of the effect of such factors as radiation and immobilization stress on the body separately and in combination is relevant since the modern conditions of human habitation are characterized by high urbanization, physical inactivity, and a complex radioecological situation in a number of regions. AIM: The aim of the study was to study the role of free radical oxidation in the tissues of the adrenal glands and immunocompetent organs and cells under the combined effect of a sublethal dose of gamma radiation and immobilization stress in the experiment. MATERIALS AND METHODS: The work was carried out on 40 male Wistar rats: I-control; II-subjected to immobilization stress after 1 h; III-exposed to gamma irradiation; and IV-tested combined effects (immobilization stress and gamma radiation). Before the exposure, there was topometric-dosimetric preparation of the experimental animals. To this end, the object was placed on an isocentric therapeutic desk of Terasix X-ray simulator (Czech Republic), which is similar to the therapeutic desk of the γ-irradiator by its construction and parameters. RESULTS: The results obtained make it possible to assess the role of free radical oxidation under the combined action of ionizing radiation at a sublethal dose and immobilization stress in the experiment. The combined effect was accompanied by the accumulation of diene conjugates and malondialdehyde products in homogenates and the development of double oxidative stress in the test objects. The dominant role of ionizing radiation was revealed under the combined effects of immobilization stress and radiation factor. CONCLUSIONS: In animals of the 4th group, the state of oxidative-metabolic processes was characterized by overproduction of LPO products and subsequently by depression of AO defense. The urgency of continuing research on the combined effects of radiation and stress factors on public health and taking measures to eliminate negative effects on the population seems to be undoubted.

Radiofrequency at 2.45 GHz increases toxicity, pro-inflammatory and pre-apoptotic activity caused by black carbon in the RAW 264.7 macrophage cell line

Environmental factors such as air pollution by particles and/or electromagnetic fields (EMFs) are studied as harmful agents for human health. We analyzed whether the combined action of EMF with fine and coarse black carbon (BC) particles induced cell damage and inflammatory response in RAW 264.7 cell line macrophages exposed to 2.45 GHz in a gigahertz transverse electromagnetic (GTEM) chamber at sub-thermal specific absorption rate (SAR) levels. Radiofrequency (RF) dramatically increased BC-induced toxicity at high doses in the first 24 h and toxicity levels remained high 72 h later for all doses. The increase in macrophage phagocytosis induced after 24 h of RF and the high nitrite levels obtained by stimulation with lipopolysaccharide (LPS) endotoxin 24 and 72 h after radiation exposure suggests a prolongation of the innate and inflammatory immune response. The increase of proinflammatory cytokines tumor necrosis factor-α, after 24 h, and of interleukin-1β and caspase-3, after 72 h, indicated activation of the pro-inflammatory response and the apoptosis pathways through the combined effect of radiation and BC. Our results indicate that the interaction of BC and RF modifies macrophage immune response, activates apoptosis, and accelerates cell toxicity, by which it can activate the induction of hypersensitivity reactions and autoimmune disorders.

Combined treatment with silver graphene quantum dot, radiation, and 17‐AAG induces anticancer effects in breast cancer cells

We aimed to investigate the possible anticancer effects of radiation in combination with 17-allylamino-17-demethoxy geldanamycin (17-AAG) and silver graphene quantum dot (SQD) in breast cancer (BC) cells. MCF-7 BCcells treated with, or without, different concentrations of 17-AAG and synthesized SQD and cellular viability detected. The growth inhibitory effects of low concentrations of 17-AAG with minimally toxic concentration of SQD in combination with 2 Gy of X-ray radiation were examined. The apoptosis induction assessed by acridine orange/ethedium bromide staining. Likewise, the levels of lactate, hydrogen peroxide (H2 O2 ), nitric oxide (NO) were evaluated. The relative gene expression levels of Bax and Bcl-2 were detected by real-time polymerase chain reaction and the Bax/Bcl-2 expression ratio was determined. Moreover, the protein expression of epidermal growth factor receptor (EGFR) was assessed by western blot analysis. Treatment with low concentrations of 17-AAG and SQD at a minimally toxic concentration promoted inhibition of BC cell growth and induced apoptosis. In addition, significant reduction in cell viability was seen in triple combination versus all double and single treatments. Indeed 17-AAG and SQD in combined with radiation significantly increased the H2 O2 and NO versus single and double treated cases. In addition, triple combination treatment showed decreased lactate level in compared tomonotherapies. EGFR protein expression levels were found to decreased in all double and triple combined cases versus single treatments. Additionally, in double and triple treatments, Bax/Bcl2 ratio were higher in compared to single treatments. Treatment with low concentrations of 17-AAG and SQD at a minimally toxic concentration tends to induce anticancer effects and increase the radiation effects when applied with 2 Gy of radiation versus radiation monotherapy.

Magneto-hydro dynamic squeezed flow of Williamson fluid transiting a sensor surface

The present article reports the combined effects of radiation and heat origination on the electro-kinetically induced hydromagnetic squeezed flow of a pseudoplastic fluid. The fluid is passing over a microcantilever sensor surface positioned in the superficial free stream. Microcantiliver sensor can detect the flow rate and the variance in the temperature of the fluid. The thermal conductivity and fluid viscosity are assumed as a function of temperature. Boundary layer approximations are considered to construct a pseudoplastic fluid flow model. The governing system is then resolved into a non-dimensional form with the assistance of an appropriate set of control parameters. The solution to these non-dimensional equations has calculated with the assistance of familiar numerical techniques i.e. Shooting technique. The results specify that flow of fluid, temperature, and velocity profiles are remarkably influenced by the radiation parameter, fluid parameter, heat generation parameter, thermal relaxation parameter, magnetic parameter, and the squeezing number. A comprehensive graphical and tabular study is constructed to check the convergence of the obtained results. One can detect that the temperature curve is changing slightly for the Christov-Cattaneo heat transfer model as compared to classical Fourier's law of heat transfer. Further, the physical quantities, i.e. free stream velocity, variable viscosity, thermal conductivity, Weissenberg number, and Prandtl number have strong impacts on the boundary layer flow equations. It is perceived that the fluid velocity profile rises for the growing value of the magnetic parameter, but reduces for squashed flow index b. Also, a positive variation is found in the temperature profile for rising values of β and Q.

Simultaneous effects of radiation, magnetic field on peristaltic flow of Carreau nanofluid submerged in gyrotactic microorganisms with heat and mass transfer

AbstractOur study intends to examine the combined effects of radiation, magnetic field, and chemical reaction on the peristaltic flow of a non‐Newtonian fluid containing gyrotactic microorganisms and nanoparticles. The system of our equations is understood numerically by using the Rung‐Kutta‐Merson method with Newton iteration in a shooting and matching procedure. The effect of physical implanted parameters is represented and discussed through a lot of charts for velocity, temperature, nanoparticle concentration, the density of motile microorganisms. From this discussion, we notice that the motile microorganisms profile is affected by the arising with the Brownian motion parameter and radiation parameter but the thermophoresis parameter, traditional Lewis number, and bioconvection of Peclet number are decremented the motile microorganisms profile.

Effect of ultraviolet treatment (UV–C) combined with nisin on industrialized orange juice in Alicyclobacillus acidoterrestris spores

Alicyclobacillus acidoterrestris is a bacteria capable of spoiling industrialized orange juice, making it a problem for the beverage industry. This study evaluated the effect of UV-C radiation in combination with nisin in the reduction of A. acidoterrestris spores using reconstituted orange juice. A. acidoterrestris spores were treated with nisin (7.81 and 15.62 μg/mL) in combination with different doses of UV-C (from 2.52 to 12.6 kJ/m2). The presence of vitamins in the juice after the treatments was investigated by UHPLC-HRMS using a ultra high performance liquid chromatography system. The combination of UV-C and nisin treatment showed counts below the detection limit of the method (<1.7 log CFU/mL) both at time 6 min (5.04 kJ/m2) with 7.81 μg/mL nisin and at time 3 min (2.52 kJ/m2) with 15.62 μg/mL nisin (p < 0.05). Ascorbic acid was found in control and 3-min UV-C samples, but with 15 min of treatment the vitamin was not detected. Thiamine was found in the three samples analyzed (T0, T3 and T15). Treatment with UV-C combined with low dose nisin (2.52 kJ/m2) eliminated spores without degrading the analyzed juice vitamins and is a promising alternative for the beverage industry.

Membrane bulge test rig for irradiation-assisted stress-corrosion cracking

During their service in a nuclear power plant, structural materials are subject to high temperature, mechanical stress, corrosive coolant environments, and neutron irradiation. The combination of radiation, corrosion and thermo-mechanical loading represents a unique environment that materials must endure: radiation can significantly alter the material’s thermo-mechanical performance and the lifetime of a component. The conditions under which this happens are difficult to study and normally necessitate nuclear reactor experiments followed by post-irradiation examination in hot cells, which renders investigations complex, time consuming and expensive. While few attempts have been made to study the combined effects of radiation and corrosion with lead bismuth eutectic [1] or molten salts [2] none of these experimental set-ups were designed to study the combination of corrosion and irradiation together with mechanical loading. Here the development of a miniature test technique is presented where irradiation, corrosion and strain can synergistically be applied on a material in a controlled way. The experiment is based on scaling down the membrane bulge test [3], using liquid lead as a pressure medium at high temperature. Membrane type specimens are made from the structural material to study, with their back side pressurized thereby inducing corrosion and membrane stretching stress while irradiation damage is generated by proton irradiation at the front surface affecting the entire thickness to the back side of the sample. The paper presents the way how the engineering problems related to the combination of corrosion by liquid metal, stress application and irradiation of the sample have been addressed.