The purpose of this study is to determine the effects of low-dose radiation on fibroblast cells irradiated by spectrally and dosimetrically well-characterized soft x-rays. To achieve this, a new cell ...culture x-ray irradiation system was designed. This system generates characteristic fluorescent x-rays to irradiate the cell culture with x-rays of well-defined energies and doses. 3T3 fibroblast cells were cultured in cups with Mylar® surfaces and were irradiated for one hour with characteristic iron (Fe) K x-ray radiation at a dose rate of approximately 550 μGy/hr. Cell proliferation, total protein analysis, flow cytometry, and cell staining were performed on fibroblast cells to determine the various effects caused by the radiation. Irradiated cells demonstrated increased proliferation and protein production compared to control samples. Flow cytometry revealed that a higher percentage of irradiated cells were in the G0/G1 phase of the cell cycle compared to control counterparts, which is consistent with other low-dose studies. Cell staining results suggest that irradiated cells maintained normal cell functions after radiation exposure, as there were no qualitative differences between the images of the control and irradiated samples. The result of this study suggest that low-dose soft x-ray radiation might cause an initial pause, followed by a significant increase, in proliferation. An initial "pause" in cell proliferation could be a protective mechanism of the cells to minimize DNA damage caused by radiation exposure. The new cell irradiation system developed here allows for unprecedented control over the properties of the x-rays given to the cell cultures. This will allow for further studies on various cell types with known spectral distribution and carefully measured doses of radiation, which may help to elucidate the mechanisms behind varied cell responses to low-dose x-rays reported in the literature.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper offers a comprehensive examination of the development and implementation of advanced safety protocols in the Patient Positioning System (PPS) for radiosurgery. In an era where precision ...and safety are increasingly crucial in medical procedures, particularly radiosurgery, the implementation of sophisticated safety measures in PPS is vital. This research delves into the detailed design of the system, emphasizing the sensor and controller mechanisms employed. A significant focus is placed on comparing single-loop and dual-loop control systems, assessing their impact on the precision, accuracy, and repeatability of the PPS. The study showcases how dual-loop control demonstrates superior performance in these areas, leading to enhanced patient safety and treatment outcomes. Additionally, the paper discusses the integration of these safety protocols within the system’s architecture, underscoring the practical implications of these advanced measures in augmenting patient safety and treatment effectiveness.
We have designed, built, and tested a climate-controlled, radiation-shielded incubator cabinet for the purpose of analyzing the effects of low-dose x-ray radiation on biological tissues and cell ...cultures. Bremsstrahlung x rays incident on exchangeable fluorescence plates produce strong, quasi-monochromatic radiation directed toward a small container of biological samples. The x-ray source, sample, and detector are enclosed in an incubator-maintaining the optimal environment for biological samples to increase longevity to a maximum of 72 h. To demonstrate the capabilities of the setup, an example experiment is presented. Rat vascular smooth muscle cell growth was observed after irradiation with characteristic x rays of iron, copper, and calcium to impart doses of 2 mGy each. Cultures show significant spectrum dependent increases in cell number over controls at 48 h after irradiation. The experiment lends credence to the efficacy of the apparatus and shows promise for future low-dose bio-radiation studies.
ABSTRACTThis study examined the factors that influence IT service desk customer satisfaction and the influence corporate social media usage has on IT service desk customer satisfaction. The ...independent variables chosen for this study were E-Ticket system Convince, IT service desk perceived performance, IT service desk expectations, IT service desk response time, and computer self-efficacy. The moderating variable was corporate social media usage. The dependent variable was IT service desk customer satisfaction. The study answered two research questions: What are the factors that influence customer satisfaction with an IT service desk? What are the moderating effects of corporate social media usage on IT service desk CS? The questions were answered by gathering survey data on a 6-point Likert scale via Survey Monkey Audience Program. Seven hypotheses were tested, and two were accepted. The two that were accepted showed that IT service desk perceived performance and IT service desk expectations significantly impacted IT service desk customer satisfaction with P-values < .05. This study also had several open-ended questions to gather the respondent’s general opinions on the IT service desk. One of the themes was that the response time was slow. Given that response time did not show a significant impact on IT service desk customer satisfaction, it is recommended that future studies focus on IT service desk response time to better understand the effects and how they are measured in relation to customer satisfaction to understand the discrepancy between the data and the opinions. Corporate social media usage showed no moderation effects; it is recommended that future studies review who uses corporate social media and the factors that determine its level of usage.
Purpose
The purpose of this work was to explore two novel operation modalities of the rotating gamma systems (RGS) that could expand its clinical application to lesions in close proximity to critical ...organs at risk (OAR).
Methods
The approach taken in this study consists of two components. First, a Geant4‐based Monte Carlo (MC) simulation toolkit is used to model the dosimetric properties of the RGS Vertex 360™ for the normal, intensity modulated radiosurgery (IMRS), and speed modulated radiosurgery (SMRS) operation modalities. Second, the RGS Vertex 360™ at the Rotating Gamma Institute in Debrecen, Hungary is used to collect experimental data for the normal and IMRS operation modes. An ion chamber is used to record measurements of the absolute dose. The dose profiles are measured using Gafchromic EBT3 films positioned within a spherical water equivalent phantom.
Results
A strong dosimetric agreement between the measured and simulated dose profiles and penumbra was found for both the normal and IMRS operation modes for all collimator sizes (4, 8, 14, and 18 mm diameter). The simulated falloff and maximum dose regions agree better with the experimental results for the 4 and 8 mm diameter collimators. Although the falloff regions align well in the 14 and 18 mm collimators, the maximum dose regions have a larger difference. For the IMRS operation mode, the simulated and experimental dose distributions are ellipsoidal, where the short axis aligns with the blocked angles. Similarly, the simulated dose distributions for the SMRS operation mode also adopt an ellipsoidal shape, where the short axis aligns with the angles where the orbital speed is highest. For both modalities, the dose distribution is highly constrained with a sharper penumbra along the short axes.
Conclusions
Dose modulation of the RGS can be achieved with the IMRS and SMRS modes. By providing a highly constrained dose distribution with a sharp penumbra, both modes could be clinically applicable for the treatment of lesions in close proximity to critical OARs.
This paper presents a comprehensive study on the application of forward kinematics in the development and control of an innovative Patient Positioning System (PPS) for radiosurgery treatment. The ...proposed PPS, consisting of a linear rail system, a linkage system, and a tabletop, synergizes to enable precise human body positioning.The standout feature of our PPS is the linkage system, equipped with four linkage arms-three active and one passive. Together, these arms facilitate diverse motions, allowing for rotation, translation, and inclination of the endpoint, thereby providing unmatched precision and versatility. Forward kinematics profoundly enhances the design and operational capabilities of the robotic linkage and the positioning system as a whole.In addressing the positional challenges posed by the PPS's robotic components, remarkable accuracy has been achieved in the system's kinematic modeling. A crucial aspect of our findings revolves around the error analysis. By applying single and dual loop control methods, significant advancements have been made in minimizing positional errors, thereby enhancing the PPS's accuracy and reliability. Detailed insights into the error, including the Heat Matrix, will be discussed in-depth within the paper, following a robust experimental validation using MATLAB and a comparative assessment with CAD model measurements.
This study presents a comprehensive kinematic analysis of a subsystem for a novel patient positioning system (PPS) aimed at accurately positioning a human body for radiosurgery treatment. The linkage ...system, which forms the core of the PPS, comprises four linkage arms, three of which are active and one passive, responsible for the rotation, translation, and inclination of the end point. The design of the robotic linkage was performed using both Forward Kinematics (FK) and Inverse Kinematics (IK) methods. The position problem of the robotic linkage was resolved through a kinematic modeling process. The performance of the modeled system was validated through experimentation using MATLAB. The results of the experimental validation indicate an ultra-high level of accuracy for the kinematic model.
Social exclusion creates a powerful motivation for individuals to seek affiliation with others. Satisfying this affiliative motive would be facilitated by the ability to detect cues in others ...indicative of their own affiliative propensity. Given the association of extraverted personality with affiliative interest and social access, gravitating toward more extraverted others could serve to ensure satisfaction of one's own affiliation goals. Consistent with past research, we hypothesized that social exclusion (relative to social inclusion) would heighten preferences for faces that veridically connote extraversion. Results partially supported this primary hypothesis as socially excluded men upregulated their preferences for extraverted faces following an exclusionary experience, whereas no difference emerged for women's extraversion preferences based on inclusionary status. These findings suggest men favored the affiliative benefits of extraversion over its potential interpersonal costs following exclusion. Conversely, socially included men did not prefer extraverted faces, which could reflect greater wariness of dominant conspecifics, despite the potential gregariousness communicated in target faces, when such men's affiliative needs are adequately met. We frame these results using an evolutionary framework discussing how salient needs influence interpersonal preferences.
•Participants played Cyberball before indicating preferences in face pairs.•Faces were manipulated to communicate high and low levels of extraversion.•Socially included men did not prefer extraversion.•Women and excluded men preferred extraversion.
Humor is considered a valuable trait when evaluating potential mates, and women demonstrate a preference for men's ability to produce humor. Humor displays as a male mating strategy appear ...context-dependent, which suggests that women's preferences for certain humor may be contingent on their mating goals. One dimension of humor variability that could approximate men's long- (LTM) or short-term (STM) mating goals is communication of humor that is categorically clean or dirty, respectively, which could influence the humorists' desirability to women. Such displays may differentially signal sexual receptivity. Two studies tasked women with indicating interest in men who generated either clean or dirty humor. Across both studies clean humor producers were preferred when evaluating both the long- and short-term desirability of men, although this preference was larger for LTM evaluations. Study 2 also demonstrated that sociosexually unrestricted women (i.e., those with more permissive sexual attitudes) self-reported greater behavioral attraction toward dirty humorists, a preference mediated by their perceptions of dirty jokes as funnier. Dirty humor production in men and appreciation in women may facilitate respective STM goals. Results of this research provide further evidence that the specific mating context determines the appropriateness of humor use when used as a relational display.
•Dirty jokes may potentially signal men's sexual receptivity.•Clean jokes may signal long-term mating desirability.•Women found clean humorists as better long- and short-term mates.•Women with sociosexually unrestricted attitudes prefer dirty humorists.
Lay skepticism toward empirically supported scientific research has increased significantly in recent years. Given that part of the social contract of science is the betterment of society, it is ...critical for the scientific community to identify factors underlying public dismissal versus support of scientific evidence. The current study explores how individual differences in political ideology influence acceptance of factual and nonfactual information, with differences in truth-seeking values as a potential mediating variable. Participants rated their agreement with true and untrue (i.e., nonempirically supported) statements and completed self-report assessments of political ideology and personal endorsement of values associated with promoting truth. More politically, liberal individuals reported greater agreement with both scientific facts and untrue statements. Furthermore, endorsement of truth-seeking values mediated the relation between liberal ideology and agreement with facts (but not nonfactual statements). Results suggest that interventions to increase individuals’ acceptance of facts may benefit from stimulating greater support for truth-seeking values and behavior.
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