Abstract
We present the first statistical analysis of complexity changes affecting the magnetic structure of interplanetary coronal mass ejections (ICMEs), with the aim of answering the questions: ...How frequently do ICMEs undergo magnetic complexity changes during propagation? What are the causes of such changes? Do the in situ properties of ICMEs differ depending on whether they exhibit complexity changes? We consider multispacecraft observations of 31 ICMEs by MESSENGER, Venus Express, ACE, and STEREO between 2008 and 2014 while radially aligned. By analyzing their magnetic properties at the inner and outer spacecraft, we identify complexity changes that manifest as fundamental alterations or significant reorientations of the ICME. Plasma and suprathermal electron data at 1 au, and simulations of the solar wind enable us to reconstruct the propagation scenario for each event, and to identify critical factors controlling their evolution. Results show that ∼65% of ICMEs change their complexity between Mercury and 1 au and that interaction with multiple large-scale solar wind structures is the driver of these changes. Furthermore, 71% of ICMEs observed at large radial (>0.4 au) but small longitudinal (<15°) separations exhibit complexity changes, indicating that propagation over large distances strongly affects ICMEs. Results also suggest that ICMEs may be magnetically coherent over angular scales of at least 15°, supporting earlier theoretical and observational estimates. This work presents statistical evidence that magnetic complexity changes are consequences of ICME interactions with large-scale solar wind structures, rather than intrinsic to ICME evolution, and that such changes are only partly identifiable from in situ measurements at 1 au.
The radial expansion of coronal mass ejections (CMEs) is known to occur from remote observations, from the variation of their properties with radial distance, and from local in situ plasma ...measurements showing a decreasing speed profile throughout the magnetic ejecta (ME). However, little is known on how local measurements compare to global measurements of expansion. Here, we present results from the analysis of 42 CMEs measured in the inner heliosphere by two spacecraft in radial conjunction. The magnetic-field decrease with distance provides a measure of their global expansion. Near 1 au, the decrease in their bulk speed provides a measure of their local expansion. We find that these two measures have little relation with each other. We also investigate the relation between characteristics of CME expansion and CME properties. We find that the expansion depends on the initial magnetic-field strength inside the ME, but not significantly on the magnetic field inside the ME measured near 1 au. This is indirect evidence that CME expansion in the innermost heliosphere is driven by the high magnetic pressure inside the ME, while by the time the MEs reach 1 au, they are expanding due to the decrease in the solar-wind dynamic pressure with distance. We also determine the evolution of the ME tangential and normal magnetic-field components with distance, revealing significant deviations as compared to the expectations from force-free field configurations as well as some evidence that the front half of MEs expand at a faster rate than the back half.
We examine 188 coronal mass ejections (CMEs) measured by the twin Solar Terrestrial Relations Observatory spacecraft during 2007-2016 to investigate the generic features of the CME sheath and the ...magnetic ejecta (ME) and dependencies of average physical parameters of the sheath on the ME. We classify the CMEs into three categories, focusing on whether the ME drives both a shock and sheath, or only a sheath, or neither, near 1 au. We also re-evaluate our initial classification through an automated algorithm and visual inspection. We observe that even for leading-edge speeds greater than 500 km s−1, 1 out of 4 MEs do not drive shocks near 1 au. MEs driving both shocks and sheaths are the fastest and propagate in high magnetosonic solar wind, whereas MEs driving only sheaths are the slowest and propagate in low magnetosonic solar wind. Our statistical and superposed epoch analyses indicate that all parameters are more enhanced in the sheath regions following shocks than in sheaths without shocks. However, differences within sheaths become statistically less significant for similar driving MEs. We also find that the radial thickness of ME-driven sheaths apparently has no clear linear correlation with the speed profile and associated Mach numbers of the driver.
Abstract
We present a comprehensive statistical analysis of 106 sheath regions driven by coronal mass ejections and measured near 1 au. Using data from the STEREO probes, this extended analysis ...focuses on two discrete categorizations. In the first categorization, we investigate how the generic features of sheaths change with their potential formation mechanisms (propagation sheaths and expansion sheaths), namely, their associations with magnetic ejectas (MEs), which are primarily propagating or expanding in the solar wind. We find propagation sheaths to be denser and driven by stronger MEs, whereas expansion sheaths are faster. Exploring the temporal profiles of these sheaths with a superposed epoch technique, we observe that most of the magnetic field and plasma signatures are more elevated in propagation sheaths relative to expansion sheaths. The second categorization is based on speed variations across sheaths. Employing linear least-squares regression, we categorize four distinct speed profiles of the sheath plasma. We find that the associated shock properties and solar cycle phase do not impact the occurrence of such variations. Our results also highlight that the properties of the driving MEs are a major source of variability in the sheath properties. Through logistic regression, we conclude that the magnetic field strength and the ME speed in the solar wind frame are likely drivers of these speed variations.
Spontaneous tumor regression Salman, Tarik
Journal of oncological science,
April 2016, 2016-04-00, 2016-04-01, Letnik:
2, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Spontaneous tumor regression is defined as spontaneous remission or disappearance of a tumor in the absence of any treatment. Activation of immune system has been found important in its pathogenesis. ...Further, spontaneous tumor regression appears to be associated with apoptosis, tumor microenvironment, and DNA oncogenic suppression. It can be observed in all types of tumors, most frequently in renal cell cancer, germ cell tumors, malignant melanoma, and neuroblastoma. It is crucial to understand this phenomenon in order to improve the immune treatments which are effective in neoplastic diseases.
Abstract
We present an analysis of in situ and remote-sensing measurements of a coronal mass ejection (CME) that erupted on 2021 February 20 and impacted both the Solar TErrestrial RElations ...Observatory (STEREO)-A and the Wind spacecraft, which were separated longitudinally by 55°. Measurements on 2021 February 24 at both spacecraft are consistent with the passage of a magnetic ejecta (ME), making this one of the widest reported multispacecraft ME detections. The CME is associated with a low-inclined and wide filament eruption from the Sun’s southern hemisphere, which propagates between STEREO-A and Wind around E34. At STEREO-A, the measurements indicate the passage of a moderately fast (∼425 km s
−1
) shock-driving ME, occurring 2–3 days after the end of a high speed stream (HSS). At Wind, the measurements show a faster (∼490 km s
−1
) and much shorter ME, not preceded by a shock nor a sheath, and occurring inside the back portion of the HSS. The ME orientation measured at both spacecraft is consistent with a passage close to the legs of a curved flux rope. The short duration of the ME observed at Wind and the difference in the suprathermal electron pitch-angle data between the two spacecraft are the only results that do not satisfy common expectations. We discuss the consequence of these measurements on our understanding of the CME shape and extent and the lack of clear signatures of the interaction between the CME and the HSS.
Abstract
On 2022 February 15, an impressive filament eruption was observed off the solar eastern limb from three remote-sensing viewpoints, namely, Earth, STEREO-A, and Solar Orbiter. In addition to ...representing the most-distant observed filament at extreme ultraviolet wavelengths—captured by Solar Orbiter's field of view extending to above 6
R
⊙
—this event was also associated with the release of a fast (∼2200 km s
−1
) coronal mass ejection (CME) that was directed toward BepiColombo and Parker Solar Probe. These two probes were separated by 2° in latitude, 4° in longitude, and 0.03 au in radial distance around the time of the CME-driven shock arrival in situ. The relative proximity of the two probes to each other and the Sun (∼0.35 au) allows us to study the mesoscale structure of CMEs at Mercury's orbit for the first time. We analyze similarities and differences in the main CME-related structures measured at the two locations, namely, the interplanetary shock, the sheath region, and the magnetic ejecta. We find that, despite the separation between the two spacecraft being well within the typical uncertainties associated with determination of CME geometric parameters from remote-sensing observations, the two sets of in situ measurements display some profound differences that make understanding the overall 3D CME structure particularly challenging. Finally, we discuss our findings within the context of space weather at Mercury's distance and in terms of the need to investigate solar transients via spacecraft constellations with small separations, which has been gaining significant attention during recent years.
Introduction
Sarcopenia is defined as the loss of muscle mass and muscular functioning. Although sarcopenia prevalence is highly variable in the literature, pre-chemotherapy sarcopenia prevalence was ...not well studied in newly diagnosed cancer patients. In this context, the present study aims to determine the prevalence of sarcopenia and its related factors in this population.
Material and methods
Prospectively, newly diagnosed cancer patients were evaluated for body composition measurement and muscle strength by employing the bioelectric impedance analysis method and handgrip dynamometer tool.
Results
A total of 461 patients were included in the study. The median age of patients was 59 years (range 18–83) and 258 patients (56%) were women. Sarcopenia was present in 77 patients (16.7%) and was at significantly higher frequencies in men (
p
= 0.015), advanced age (≥ 65 years,
p
= 0.014), lower body mass index (BMI < 25,
p
= < 0.001), and poor performance status (ECOG status > 0,
p
= 0.026). In multivariate analyses, advanced age (over 65 years), gender (men), and lower body mass index (BMI < 25) were significantly associated with sarcopenia (
p
values 0.033, < 0.001, and < 0.001, respectively).
Conclusions
Our study is the first prevalence study conducted with bioelectric impedance analysis on Turkish cancer patients and sarcopenia was detected to be notably prevalent among our patients with newly diagnosed cancer. Given the likely negative outcomes of sarcopenia reported in the literature (treatment failure, increased complications, and impaired survival), it is important to know the presence of sarcopenia before treatment and take preventive precautions.
Background
Sarcopenia is associated with physical disability, increased post-operative complications, poorer tolerance to chemotherapy, and reduced survival outcome. However, little is known about ...the changes in body composition during chemotherapy treatment. We aimed to determine whether adjuvant or palliative chemotherapy causes the development of sarcopenia in newly diagnosed cancer patients and to reveal the relationship of sarcopenia with the duration of chemotherapy.
Methods
The study included newly diagnosed cancer patients who underwent curative surgery for primary tumor and also cancer patients who were metastatic at diagnosis. Body composition and handgrip strength were assessed by bio-electric impedance analysis (BIA) and handgrip dynamometer tools, respectively. Measurement tests were performed prior to chemotherapy, in the third and sixth months of chemotherapy.
Results
The median age of a total of 276 patients was 57.5 years (range 18–83), and majority of them (55.8%) were women. Among the pre-chemotherapy factors that could be associated with sarcopenia, male gender ≥ 65 years of age, body mass ındex (BMI) < 25, and nutritional risk screening 2002 score < 3 were found to be positively associated with sarcopenia (
p
< 0.001,
p
= 0.036,
p
< 0.001, and
p
< 0.001, respectively). In the multivariate analysis, male gender (
p
< 0.001) and BMI < 25 (
p
= 0.047) were found to be significant. Of 276 patients, 14.5% were sarcopenic prior to chemotherapy. After chemotherapy, 21.4% of them were sarcopenic at the end of the third month and 23.9% were sarcopenic at the end of the sixth month.
Conclusion
The incidence of sarcopenia was found to be increased with chemotherapy itself and its duration in both non-metastatic and metastatic cancer patients which has to be evaluated in detail in disease-specific prospective and randomized studies.
Introduction
Although the chemotherapy-induced sarcopenia has some explanatory presence in clinical practice, the mechanisms underlying this phenomenon have not been clearly distinguished in patients ...with cancer. Therefore, we aimed with this study to investigate the role of inflammation by examining the inflammatory markers in the physiopathology of adjuvant chemotherapy-induced sarcopenia in patients with gastrointestinal tract cancer.
Material and method
To detect the presence of sarcopenia, patients’ body composition measurements were assessed using the BIA, and their muscular strength was assessed with a handgrip dynamometer in both pre- and post-adjuvant chemotherapy. At the same time, we examined the baseline and post-adjuvant chemotherapy anthropometric measurements and inflammatory markers in serum (Hs-CRP, IL8, and TNF-α). Patients were divided in three groups. Group 1 consisted of patients who presented post-treatment sarcopenia although they did not have it prior to the treatment, group 2 included the patients who had no pre- or post-treatment sarcopenia, and group 3 was comprised of patients who presented pre-treatment sarcopenia. Each group included 30 patients.
Results
A total of 90 patients were included in the study. Fifty-one of them were female patients. Median age was 60.5 (range 27–83). The patients consisted of cases with colorectal and gastric cancers. In group 1, Wilcoxon signed-rank test revealed a significant difference between scores of IL-8 (pg/mL), TNF-α (pg/mL) and Hs-CRP (mg/dL) given for the post-chemotherapy compared with the pre-chemotherapy ((
Z
3.61,
p
< 0.001), (
Z
3.254,
p
= 0.001), (
Z
3.319,
p
= 0.001)). The post-chemotherapy median scores of IL-8 (pg/mL), TNF-α (pg/mL), and Hs-CRP were 76.31, 7.34, and 1.55, respectively, which remained on the levels of 12.25, 1.6, and 0.51 for the pre-chemotherapy. For group 2, a Wilcoxon signed-rank test indicated no significant difference between scores of the same markers given for the post-chemotherapy compared with the pre-chemotherapy. In all patients (including groups 1, 2, and 3), a comparison of the patients with pre-treatment sarcopenia (
n
= 30) and non-sarcopenic patients (
n
= 60) in terms of baseline IL-8, TNF-α, and Hs-CRP mean levels, IL-8 and Hs-CRP were found to be statistically different (146.02 (SD 311.96) vs. 47.24 (SD 66.3) (
p
= 0.009), 3.91 (SD 4.26) vs. 0.75 (SD 1.08) (
p
< 0.001), respectively).
Conclusions
The present prospective observational study suggested an association of chemotherapy-induced sarcopenia with inflammatory markers Hs-CRP, IL8, and TNF-α. Inflammation may play a role in chemotherapy-induced sarcopenia in newly diagnosed non-metastatic patients.
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