Relative Volume Change Research Articles

29. Natural History of Breast Cancer-related Lymphedema

PURPOSE: Although breast Cancer-related lymphedema (BCRL) is a chronic disease, the rate of progression is highly variable. The purpose of this prospective longitudinal study was to analyze the natural history of BCRL after axillary lymph node dissection (ALND) and identify predictive variables that may regulate the trajectory of the disease. METHODS: Between 2016 and 2020, we performed baseline arm volume measurements and prospectively followed patients who underwent ALND at a tertiary cancer center every 6 months for 3 years. Demographic data and relative volume change (RVC) were recorded. Patients were divided into four disease trajectories based on RVC (no disease RVC<5%, mild RVC 5-10%, moderate RVC 10-20%, severe RVC>20%) and analyzed using an ordinal logistic regression model. RESULTS: 292 patients with a mean follow-up time of 32.7±6 months were included in the study. Lymphedema (defined as an RVC ≥5%) developed in 39.4% of patients, on average 14.6 months after surgery. Postoperative radiation therapy was the strongest predictor of severe disease trajectory (OR 8.98, 95% CI 1.68-167, p=0.007), followed by African American race (OR 2.16, 95% CI 1.15-4.03, p=0.011), older age (OR 1.03, 95% CI 1.00-1.05 p=0.02) and higher baseline volume differential (OR 0.94, 95% CI 0.89-0.94, p=0.014). Neither chemotherapy nor referral for lymphedema therapy/compression had a significant impact on the disease trajectory. CONCLUSION: This is the largest prospective longitudinal study to identify predictive factors associated with severe BCRL disease trajectory. This information can be used to prioritize aggressive preventative measures such as immediate lymphatic reconstruction or immediate postoperative physical therapy

Transformation strain and volume effect associated with martensitic transformation in polycrystalline Ni49+x+yMn23-xGa28-y Heusler alloys

Combined thermal strain and magnetization measurements were performed in polycrystalline alloys Ni49.31Mn22.76Ga27.93(Ni49), Ni53.00Mn21.04Ga25.96(Ni53) and Ni55.62Mn17.52Ga26.86(Ni55.5) to understand the influence of magnetic field (B) on transformation strain (Δλ) and relative volume change (ω) at martensitic transformation (MT). It is found that during cooling and heating both Ni49 and Ni53 samples undergo a MT while the Ni55.5 sample experiences a coupled magnetostructural transformation (MST). Such a MST can enhance the Δλ and ω whereas thermal hysteresis weakens them, which results in a non-monotonic variation in Δλ: 0.211% (Ni49) → 0.166% (Ni53) → 0.185% (Ni55.5) under B = 0 T. Similar tendency was observed in ω. Besides, the values of Δλ and ω increase with increasing field, partially due to the contribution of magnetic field-induced strain. The maximum value ω = 0.674% was obtained in Ni49 sample under 3 T, indicating that an extra volume space of ∼1% should be needed to avoid the destruction of refrigeration chamber. These findings provide key information for future use of Ni–Mn-Ga alloys in refrigeration engineering field.

Abstract P6-03-04: Ipsilateral infusions are not associated with increased risk of breast cancer-related lymphedema in patients enrolled in a prospective screening program

Abstract BACKGROUND: Patients treated for breast cancer (BC) who are at risk of breast cancer-related lymphedema (BCRL) have been instructed for decades to avoid venipuncture, injections and infusions in the extremity ipsilateral to BC treatment. These instructions are given in theory to prevent BCRL development, despite lack of supporting data. Given fear of BCRL is high amongst the population at risk, it has been found that patients heed this advice regardless of level of BCRL risk. It has been previously found that there is no association between blood draws or injections in the ipsilateral arm and increases in arm volume in patients treated for BC and screened for BCRL. Despite these findings, risk of BCRL associated with the most invasive of BC treatments, infusions in the ipsilateral arm, has not been examined. As patients with BC require ongoing invasive medical procedures, data would inform patient care and drive clinical practice guidelines during and after BC treatment. PURPOSE: The purpose of this study was to determine whether patients treated for breast cancer who receive one or more infusions in the arm ipsilateral to BC treatment are at higher risk of BCRL than those who do not receive ipsilateral infusions. METHODS: From 2005 to 2021, 2049 patients treated for BC were enrolled in a prospective BCRL screening trial and screened from preoperative baseline through last follow-up. Screening included objective arm volume measurements via perometry; relative volume change (RVC) increase ≥10% from preoperative baseline &amp;gt;3 months postoperatively was used to define BCRL. Infusions data were collected directly from the electronic medical record and all postoperative infusions were included in data analysis. Patients were censored at cancer recurrence. Infusions data included route, laterality, date and substance infused. Demographic and clinical information were obtained through medical record review. Marginal structural models were used to estimate the hazard of BCRL attributable to any (vs. no) ipsilateral infusion. Time-varying inverse-probability weights were used to account for time-varying confounding by RVC and earlier adjuvant infusions, and adjusted for baseline confounding by baseline BMI, axillary lymph node dissection (ALND), regional lymph node radiation (RLNR), neoadjuvant chemotherapy, and number of neoadjuvant ipsilateral infusions. RESULTS: The eligible cohort included 2018 patients. 240 patients received at least one ipsilateral infusion; 651 did not receive ipsilateral infusions; 1,127 did not receive infusions. Patients who received ipsilateral infusions received a median of 2 (interquartile range (IQR) 1, 3) ipsilateral and 8 (IQR 4, 15) total infusions. 681 (34%) patients received adjuvant chemotherapy infusions; the most frequent adjuvant regimens received included ACT (314 patients, 16%); TC (162 patients; 8.0%); and ACTH (±P) (47 patients, 2.3%). Of those who received any ipsilateral infusions, 77% had chemotherapy drugs infused, compared to 84% of participants who did not have ipsilateral infusions. Fluids, antacids, and antihistamines were the most common non-chemotherapy infusions. Patients underwent BCRL screening over a median of 5 visits (IQR 3,8) with a median follow-up of 56 months (IQR 31, 90 months). There was no significant difference in BCRL risk between patients who received at least one ipsilateral infusion and those who did not receive ipsilateral infusions (HR, 0.85; p=0.60). CONCLUSIONS: Infusions in the at-risk arm were not associated with increased risk of BCRL in this cohort of 2018 patients at risk of and prospectively screened for BCRL. Citation Format: Cheryl L. Brunelle, Amanda W. Jung, Louisa H. Smith, Kayla Daniell, Maria S. Asdourian, Loryn K. Bucci, Brooke Juhel, Elizabeth K. Hausman, George E. Naoum, Alphonse G. Taghian. Ipsilateral infusions are not associated with increased risk of breast cancer-related lymphedema in patients enrolled in a prospective screening program. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-03-04.

Abstract P1-12-05: The Impact of Adjuvant Chemotherapy, Including Taxanes, on Breast Cancer-Related Lymphedema Risk

Abstract BACKGROUND: Adjuvant chemotherapy, particularly taxane-based chemotherapies, which are used to treat high-risk breast cancers, has been shown to be efficacious in prolonging overall survival. However, the impact of such therapies on risk of breast cancer-related lymphedema (BCRL) is yet to be fully understood. Available studies have contradictory findings as to whether or not taxanes increase BCRL risk. Unfortunately, methodological flaws, such as not incorporating a preoperative baseline arm volume measurement or utilizing flawed measurement techniques and diagnostic criteria, result in misdiagnosis of the primary outcome of BCRL and it is therefore difficult to draw conclusions from these studies. As such, a more comprehensive understanding of the potential risks associated with these treatment modalities can improve quality of care as patients are better prepared to face a potentially devastating sequela of breast cancer treatment. PURPOSE: The purpose of this study is to determine if chemotherapy administered in the adjuvant setting is an independent risk factor of BCRL, as well as to assess any specific risks of taxane-based chemotherapy on BCRL. METHODS: From 2005 to 2021, 2049 patients treated for breast cancer were enrolled in a prospective BCRL screening trial and screened from preoperative baseline through last follow-up. Screening included objective arm volume measurements via perometry. Chemotherapy data and clinicopathological and demographic characteristics were collected directly from the electronic medical record. Patients who had not received neoadjuvant chemotherapy were eligible for the current study; they were classified based on whether they had received taxane-based chemotherapy, non-taxane chemotherapy only, or no chemotherapy. Relative volume change (RVC) increase ≥10% from preoperative baseline &amp;gt;3 months postoperatively was used to define BCRL. Patients were censored at cancer recurrence or most recent clinic visit. We fit a Cox regression model to estimate adjusted hazard ratios (aHR) for BCRL. The model was adjusted for baseline BMI, axillary lymph node dissection (ALND), regional lymph node radiation (RLNR), age at diagnosis, and smoking history. RESULTS: The eligible cohort included 1759 patients, including 564 (32%) who received taxane-based chemotherapy and 104 (6%) who received non-taxane chemotherapy only. The median follow-up time for the entire cohort was 58 months. 141/1759 (8%) of patients developed BCRL. The median time to develop BCRL was 21 months post-operatively. Compared to no chemotherapy, the aHR associated with taxane-based chemotherapy was 1.04 (95% CI 0.37, 1.8; p = 0.62). Compared to no chemotherapy, the aHR for non-taxane chemotherapy was 0.82 (95% CI 0.67, 1.6; p = 0.86). There was no significant difference between taxane and non-taxane therapies in terms of BCRL risk (p = 0.55). ALND, RLNR, and high BMI remained independent risk factors for BCRL, consistent with the published literature. CONCLUSION: The receipt of adjuvant chemotherapy and specifically adjuvant taxane-based chemotherapy were not associated with increased risk of BCRL in this cohort of 1759 patients at risk of and prospectively screened for BCRL. Citation Format: Amanda W. Jung, Brooke Juhel, Louisa H. Smith, Cheryl L. Brunelle, Elizabeth K. Hausman, Loryn K. Bucci, George E. Naoum, Alphonse G. Taghian. The Impact of Adjuvant Chemotherapy, Including Taxanes, on Breast Cancer-Related Lymphedema Risk [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-12-05.

Abstract P5-08-09: Does Breast Inflammation Contribute to Lymphedema Risk in Patients Treated with Axillary Lymph Node Dissection?

Abstract Background Chronic inflammatory responses initiated by lymphatic injury play a key role in the pathophysiology of secondary lymphedema. However, it is unclear if baseline inflammation or ethnic/racial variability in inflammatory responses increase lymphedema risk. Crown-like structures of the breast (CLS-B), consisting of macrophages engulfing necrotic adipocytes, are a marker of systemic inflammation and have been implicated in the pathogenesis of breast cancer, but their role in lymphedema development is unknown. Here we determine whether baseline differences in inflammation, characterized by the presence of CLS-B, contributed to lymphedema risk in a diverse cohort of patients treated with ALND. Methods Patients ≥ 18 years undergoing ALND were enrolled in a prospective lymphedema screening study. Body mass index (BMI) and volumetric arm measurements (perometer) were performed at baseline, postoperatively, and every 6 months. Breast tissue obtained at definitive surgery was assessed for CLS-B with CD-68 IHC stain in non-tumor breast tissue. Inflammation severity was determined by number of CLS-B/cm2, with the median used to differentiate between mild and severe inflammation. Lymphedema was defined as a relative arm volume change of ≥10%. Lymphedema incidence was assessed using competing risk analysis and compared between patients with and without CLS-B. Uni- and multivariable analysis was performed to identify factors associated with lymphedema development. Results Between 11/2016-03/2020, 304 ALND patients were enrolled; 281 had at least 6 months of follow-up and were included in the study. Eleven percent self-identified as Asian, 20% Black, 6% Hispanic, and 60% White. Median age was 48 years; median BMI was 26.3 kg/m2, with higher BMI observed in Black and Hispanic women compared to Asian and White women (p &amp;lt; 0.001). Overall, 54% had CLS-B, with severe inflammation (&amp;gt; 0.4 CLS-B/cm2) identified in 71 (25%) patients. CLS-B presence correlated with BMI (36% [BMI &amp;lt; 25], 63% [BMI 25-30], 70% [BMI &amp;gt; 30], p &amp;lt; 0.001) and varied across racial/ethnic groups, with a higher prevalence in Black and Hispanic women (68% [Black], 69% [Hispanic] vs 59% [Asian], 46% [White], p = 0.03) (Table). Inflammation severity did not differ by race/ethnicity (p = 0.11). At 2.1 years median follow-up (IQR 1.6-3.1), 66 women developed lymphedema, with a 2-year lymphedema rate of 21.3% (95% CI 16.4-26.8). Lymphedema incidence was higher among Black and Hispanic women, compared to Asian and White women (2-year rate: 33.8% [Black], 31% [Hispanic], 17.4% [Asian], 18.2% [White], p = 0.002), and was higher among women with CLS-B (2-year rate: 28.2% [CLS-B] vs 12.9% [no CLS-B], p = 0.02). On multivariable analysis, Black race (White [referent]: HR 2.85, 95% CI 1.4-5.8; p = 0.03), receipt of NAC (upfront surgery [referent]: HR 2.46, 95% CI 1.04-5.8, p = 0.04) and older age (HR 1.03, 95% CI 1.01-1.06 per 1-year increase; p = 0.009) were independently associated with lymphedema development, while CLS-B was not (HR 1.37, 95% CI 0.81-2.34, p = 0.2). Conclusions In a prospective cohort of patients treated with ALND, Black race, receipt of NAC, and increasing age, but not CLS-B, were independently associated with lymphedema risk. However, the higher CLS-B prevalence in Black women suggests that they may have a propensity for increased inflammation, which may in part be contributing to the higher lymphedema risk observed, but is likely not the only inflammatory mechanism that modulates risk. Table. Clinical characteristics of study cohort stratified by the presence of CLS-B Citation Format: Andrea V. Barrio, Giacomo Montagna, Varadan Sevilimedu, Ethan Gomez, Dilip Giri, Babak Mehrara, Monica Morrow. Does Breast Inflammation Contribute to Lymphedema Risk in Patients Treated with Axillary Lymph Node Dissection? [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-08-09.

Analysis Of The Flow Pulsation Characteristics Of The Gear Pump Used in Electro-Hydrostatic Actuator

Linear conjugate internal gear pump has low noise and a smooth flow, but the mechanism of flow pulsation, especially the experiment, is seldom studied. In this paper, the flow rate formula of instantaneous, flow pulsation rate and relative volume change of the trapped oil cavity are derived by means of theoretical calculation. The pressure fluctuation characteristics of the trapped oil chamber and flow pulsation characteristics of the pump outlet are studied by using the three-dimensional fluid dynamics finite element simulation analysis method. According to the international standard of ISO10767-1-2015, the pump outlet flow pulsation test was conducted. The flow pulsation rate of a certain type of linear conjugate internal gear pump with a displacement of 10mL/r is about 6.35% under the condition of the speed of 750r/min and outlet pressure of 7.5MPa, and the flow pulsation is small.

Double-Transition-Metal MXene Films Promoting Deeply Rechargeable Magnesium Metal Batteries.

Magnesium metal batteries are promising candidates for next-generation high-energy-density and low-cost energy storage systems. Their application, however, is precluded by infinite relative volume changes and inevitable side reactions of Mg metal anodes. These issues become more pronounced at large areal capacities that are required for practical batteries. Herein, for the first time, double-transition-metal MXene films are developed to promote deeply rechargeable magnesium metal batteries using Mo2 Ti2 C3 as a representative example. The freestanding Mo2 Ti2 C3 films, which are prepared using a simple vacuum filtration method, possess good electronic conductivity, unique surface chemistry, and high mechanical modulus. These superior electro-chemo-mechanical merits of Mo2 Ti2 C3 films help to accelerate electrons/ions transfer, suppress electrolyte decomposition and dead Mg formation, as well as maintain electrode structural integrity during long-term and large-capacity operation. As a result, the as-developed Mo2 Ti2 C3 films exhibit reversible Mg plating/stripping with high Coulombic efficiency of 99.3% at a record-high capacity of 15 mAh cm-2 . This work not only sheds innovative insights into current collector design for deeply cyclable Mg metal anodes, but also paves the way for the application of double-transition-metal MXene materials in other alkali and alkaline earth metal batteries.

A Retrospective Study of Renal Growth Changes after Proton Beam Therapy for Pediatric Malignant Tumor.

The purpose of this study was to analyze renal late effects after proton beam therapy (PBT) for pediatric malignant tumors. A retrospective study was performed in 11 patients under 8 years of age who received PBT between 2013 and 2018. The kidney was exposed in irradiation of the primary lesion in all cases. Kidney volume and contour were measured on CT or MRI. Dose volume was calculated with a treatment-planning system. The median follow-up was 24 months (range, 11-57 months). In irradiated kidneys and control contralateral kidneys, the median volume changes were -5.63 (-20.54 to 7.20) and 5.23 (-2.01 to 16.73) mL/year; and the median % volume changes at 1 year were -8.55% (-47.52 to 15.51%) and 9.53% (-2.13 to 38.78%), respectively. The median relative volume change for irradiated kidneys at 1 year was -16.42% (-52.21 to -4.53%) relative to control kidneys. Kidneys irradiated with doses of 10, 20, 30, 40, and 50 GyE had volume reductions of 0.16%, 0.90%, 1.24%, 2.34%, and 8.2% per irradiated volume, respectively. The larger the irradiated volume, the greater the kidney volume was lost. Volume reduction was much greater in patients aged 4-7 years than in those aged 2-3 years. The results suggest that kidneys exposed to PBT in treatment of pediatric malignant tumor show continuous atrophy in follow-up. The degree of atrophy is increased with a higher radiation dose, greater irradiated volume, and older age. However, with growth and maturation, the contralateral kidney becomes progressively larger and is less affected by radiation.

The growth of polygenetic volcanoes in the laboratory: Control of eruptive volume and magma viscosity on edifice development and morphology

Morphometric parameters have been used to describe and classify the shape of volcanic edifices, but the processes that control these parameters are not fully understood. Here we investigate the influence of the changes in eruptive volume and magma viscosity on the edifice morphology of a simple polygenetic volcano with a fixed stable vent using analogue experiments in the laboratory. We ran the experiments by ejecting vegetable oil repeatedly at a static location in a temperature-controlled room with an adequate interval between ejections to allow this material to solidify. The experiments comprised four different scenarios: constant ejection volume and viscosity, linearly decreasing ejection volume with constant viscosity, exponentially decreasing ejection volume with constant viscosity, and increasing viscosity with constant ejection volume. We built digital elevation models from images captured by digital cameras after each ejection using photogrammetry method. We describe the shapes of the edifices using morphometric parameters, such as height, basal width, H/W ratio, volume, slope, circularity, and regularity. The experiments with decreasing ejection volume produced taller edifices with steeper slopes, especially near the summit, compared to the edifice produced with constant ejection volume. A similar finding was also observed for the edifice resulting from the experiment with increasing viscosity. The circularity and regularity indexes were insignificantly influenced by ejection volume and viscosity changes. Instead, these parameters vary with the height fraction of the edifice where the lower part is more circular, but irregular compared to the upper part. Based on the changes of morphometric variables throughout the experiments, we propose three development stages of volcanic edifice growth: basal foundation, flank construction, and vertical build-up. The development stage in which the edifice currently grows can be inferred from the relative changes in the eruptive volume and the magma viscosity. Therefore, the quantitative characterization of a natural volcanic edifice's morphology can be interpreted to explain the processes that influenced it and its stage of growth.

The Effect of the COVID-19 Pandemic on Digital Health-Seeking Behavior: Big Data Interrupted Time-Series Analysis of Google Trends.

Due to the emergency responses early in the COVID-19 pandemic, the use of digital health in health care increased abruptly. However, it remains unclear whether this introduction was sustained in the long term, especially with patients being able to decide between digital and traditional health services once the latter regained their functionality throughout the COVID-19 pandemic. We aim to understand how the public interest in digital health changed as proxy for digital health-seeking behavior and to what extent this change was sustainable over time. We used an interrupted time-series analysis of Google Trends data with break points on March 11, 2020 (declaration of COVID-19 as a pandemic by the World Health Organization), and December 20, 2020 (the announcement of the first COVID-19 vaccines). Nationally representative time-series data from February 2019 to August 2021 were extracted from Google Trends for 6 countries with English as their dominant language: Canada, the United States, the United Kingdom, New Zealand, Australia, and Ireland. We measured the changes in relative search volumes of the keywords online doctor, telehealth, online health, telemedicine, and health app. In doing so, we capture the prepandemic trend, the immediate change due to the announcement of COVID-19 being a pandemic, and the gradual change after the announcement. Digital health search volumes immediately increased in all countries under study after the announcement of COVID-19 being a pandemic. There was some variation in what keywords were used per country. However, searches declined after this immediate spike, sometimes reverting to prepandemic levels. The announcement of COVID-19 vaccines did not consistently impact digital health search volumes in the countries under study. The exception is the search volume of health app, which was observed as either being stable or gradually increasing during the pandemic. Our findings suggest that the increased public interest in digital health associated with the pandemic did not sustain, alluding to remaining structural barriers. Further building of digital health capacity and developing robust digital health governance frameworks remain crucial to facilitating sustainable digital health transformation.

Benign thyroid nodules respond to a single administration of 0.3mg recombinant human thyrotropin with highly variable volume increase.

The nature of thyroid nodules is heterogenous. Most of them are benign and, in the absence of pressure symptoms of adjunct structures, no treatment is needed. Our objective was to investigate the acute effects of a low dose of recombinant human TSH (rhTSH) on the volume of benign thyroid nodules. we studied 27 nodules (14 isoechoic and 13 hypoechoic) in 15 (11 women and 4 men; mean age: 51.0 ± 15.9 years) consecutive patients with one to three well-separated asymptomatic benign thyroid nodules. All subjects were euthyroid, with negative thyroid antibodies, and none received levothyroxine. The total thyroid volume and thyroid nodule volume were sonographically determined by two independent examiners (P.B. and M.M.) before, 48 hours and 6 months post intramuscular (IM) administration of 0.3mg rhTSH, and the mean values of the two examiners' measurements were used; thyroid function tests were obtained at the same time points. The mean volume of isoechoic nodules increased by 57.3%, of hypoechoic nodules by 46.6% and of the surrounding thyroid parenchyma by 70.4% 48 hours post-rhTSH; mean volumes had returned to baseline levels 6 months later. A large variance in the volume change responses was observed. The relative change in nodule volume (defined as the percent change in nodule volume divided by the percent change in the surrounding parenchyma) from baseline to 48 hours was significantly higher in isoechoic versus hypoechoic nodules (p<0.05). A single dose of 0.3 mg rhTSH transiently increased the volume of benign thyroid nodules. The increase was more pronounced in isoechoic nodules and had a great variability. Our findings could be useful in the management of benign thyroid nodules, by helping in understanding which nodules would be more responsive to TSH suppression therapy.

ОБҐРУНТУВАННЯ ЗАХОДІВ ЩОДО БЕЗПЕЧНОЇ РОЗРОБКИ КРУТИХ ВУГІЛЬНИХ ПЛАСТІВ

Purpose. Justification of measures regarding the safe development of steep coal seams to ensure the safe efficiency of coal mining and increase the safety of miners in deep coal mines. Methodology. In order to achieve the goal, laboratory studies of the deformation properties of protective constructions were carried out on the models subjected to uniaxial compression, and field studies of the stability of preparatory mining products with various methods of protection. Results. It was found that for coal cinders within the limits of the established deformation resource (0,10,25)) at the same time as their stiffness increases, the potential energy of deformation reaches a critical level, on which the short-term stability of protective constructions is realized. At the same time, there is a relative change in volume in the range of 0,05V0,1. With the increase in static use and the transition of the critical level of deformations, when 0,25 і V0,1, the loss of cylinder stability remains. For protective constructions made of crushed rock when they are uniaxially compressed, the change in the behavior of the deformed body is separated from the compaction of the primary material. Within the limits of the deformation resource (0,40,7), a relative change in the volume of crushed rock of 0,2V0,35 has been recorded. According to the number of sizes of such protective constructions, when the work of compression increases, the value of V decreases. At the same time, the bearing capacity of protective constructions increases. Scientific novelty. The deformation resource of protective constructions of preparatory mine workings determines the effectiveness of the protection method used. Within the limits of the deformation resource, a stable state of protective constructions is ensured, which operates under conditions of single-height compression until the critical level of the specific potential energy of deformations is reached. Practical significance. To ensure the stability of the pits in the coal-bearing massif and the operational condition of the prepared products in the mining areas, it is advisable to use partial or full laying of crushed rock or wooden chock with sleepers in the mined space.

STUDY OF DEFORMATION PROPERTIES OF PROTECTIVE STRUCTURES OF PREPARATORY MINING WORKS

Purpose. To study the stability of the security structures of the preparatory mine roadways of steep seams while unloading the coal-rock massif to prevent the collapse of side rocks in the excavation areas of the coal mine and create safe working conditions for miners. Method. In order to achieve the aim of the research, the study of the stability of security structures was carried out at the laboratory of mountain pressure by using experimental samples in the form of whole coal and structures consisted of crushed rock, which were subjected to uniaxial compression. Results. Under the conditions of uniaxial compression of whole coal or constructions consisted of crushed rock, with the ratio of length to width a/b= (1-2) and an increase in the cross-sectional area S (m2) of the experimental samples, a relative change of their volume δV was observed. For whole coal, the steady state is ensured by the relative volume change δV ≤ 0,1. Beyond the set value of δV, the whole coals lose their stability and collapse, which results in the collapse of the side rocks. For the crushed rock structures, with an increase in the cross-sectional area of the compressible specimens, the relative volume change decreases from δV = 0,2 to δV = 0,35. At the same time, the crushed rock is compacted in the whole volume of the used material, the bearing capacity of protective structures is increased, which enables limiting the movement of lateral rocks and ensures their integrity. Scientific novelty Within the limits of the deformation resource of protective structures consisting of crushed rock of different granulometric composition, with their uniaxial compression, a type of functional dependence was established, which enables us to estimate the relative change in the volume of flexible supports from stiffness, which is necessary for assessing their bearing capacity. Practical significance. In order to create safe working conditions for miners in the excavation areas of a deep coal mine and prevent the collapse of side rocks in the coal massif, it is advisable to use flexible protective structures for the protection of preparatory coal mine roadways, when the ratio of their linear dimensions corresponds to the ratio of length to width of a/b&gt;(1-2).

ЗІСТАВЛЕННЯ ДЕФОРМАЦІЙНИХ ВЛАСТИВОСТЕЙ ОХОРОННИХ СПОРУД ПІДГОТОВЧИХ ГІРНИЧИХ ВИРОБОК

Purpose. Investigate and compare the deformation properties of protective structures in the form of coal pillars and structures made of crushed rock for a justified choice of the protection method, which can make it possible to ensure the stability of side rocks in the coal massif and preparatory works in the mining areas in the coal mine. Methodology. To achieve the goal, laboratory studies were performed on experimental samples subjected to uniaxial compression. For pillars, their thickness was changed, whereas for structures made of crushed rock the thickness of the rock layer was changed at a constant cross-sectional area. Results. As a result of the conducted research, the deformation properties of protective structures that were subjected to uniaxial compression have been determined. A 15% reduction in their stiffness was recorded for pillars, when their thickness h0 was two times changed, and for the external static load, which varied according to a linear dependence. Within the limits of the safe deformation resource, when the relative deformation is in the range of values 0.18≤λ≤0.23, the stability of the pillars and their bearing capacity is ensured. At the same time, the relative change in their volume should not exceed 7-9%. It has been established that exceeding the limit level of the specific potential energy of deformation by an average of 12-14% causes the destruction of coal pillars. For protective structures made of crushed rock with a relative volume change of 0.35≤δV≤0.28, the value of the compaction coefficient of the original material decreases from kcons = 1.5 to kcons = 1.42 with a simultaneous increase in the work of compression and an increase of more than 20% in the specific potential energy of deformation, thanks to which the rigidity of the embedded material and the bearing capacity of protective structures made of crushed rock are ensured. Scientific novelty. The regularities of formation of deformation properties of protective structures under conditions of uniaxial compression, taking into account the change in the specific potential energy of deformation and the relative change in their volume, have been established. Practical significance. In order to ensure the stability of side rocks in the coal massif and preparatory workings at excavation sites in the coal mine, the feasibility of using partial or complete paving of the produced space from crushed rock, which limits the movement of side rocks in the produced space, has been substantiated.

The circulatory dynamics of human red blood cell homeostasis: Oxy-deoxy and PIEZO1-triggered changes

The vital function of red blood cells (RBCs) is to mediate the transport of oxygen from lungs to tissues and of CO2 from tissues to lungs. The gas exchanges occur during capillary transits within fractions of a second. Each oxygenation-deoxygenation and deoxygenation-reoxygenation transition on hemoglobin triggers sharp changes in RBC pH, leading to downstream changes in ion fluxes, membrane potential, and cell volume. The dynamics of these changes during the variable periods between capillary transits in vivo remains a mystery inaccessible to study by current methodologies, a knowledge gap on a fundamental physiological process that is the focus of the present study. The use of a computational model of human RBC homeostasis of tested accreditation enabled a detailed investigation of the expected RBC changes during intercapillary transits, with results advancing novel insights and predictions. The predicted rates of relative RBC volume change on oxygenation-deoxygenation (oxy-deoxy) and deoxygenation-reoxygenation transitions were about 1.5%/min and −0.9%/min, respectively, far too slow to allow the cells to reach steady states in the intervals between capillary transits. The amplitude of the oxy-deoxy-reoxygenation volume fluctuations varied in proportion with the duration of the intercapillary transit intervals. Upon capillary entry, oxy-deoxy-induced changes occur concurrently with deformation-induced PIEZO1 channel activation, both processes affecting cell pH, membrane potential, and cell volume during intertransit periods. The model showed that the effects were strictly additive as expected from processes operating independently on the cell’s homeostatic fabric. Analysis of the mechanisms behind these predictions revealed, for the first time, the complex interactions between oxy-deoxy and ion transport processes that ensure the long-term homeostatic stability of RBCs for optimal gas transport in physiological conditions and how these may become altered in diseased states. Possible designs of microfluidic devices to test the model predictions are discussed.

Thyroid volume changes following adjuvant radiation therapy for breast cancer

Background and purposeIncidental thyroid gland irradiation frequently occurs in breast cancer patients who receive regional nodal irradiation (RNI) to the supraclavicular (SCV) region. Recent studies suggest hypothyroidism (HT) is a complication of radiation therapy (RT) that includes SCV fields. We retrospectively analyzed patients who received RNI to evaluate thyroid gland evolution following RT as well as its association with the development of HT. Materials and methods61 breast cancer patients received SCV-directed RT between 2007 and 2019 and met inclusion criteria. Thyroid glands were retrospectively contoured on CT simulation and follow-up images. Individual dose-volume histograms were analyzed to determine thyroid volume within and outside specific isodose lines. Relative thyroid volume changes based on different radiation doses were estimated by fusing post-RT scans with CT simulation. Logistic regression was performed to assess thyroid volume changes as a factor in the development of HT. ResultsMedian pre-treatment thyroid volume was 11.8 cc (range: 6.3–74.1 cc) with a median of 42.2 % within the 20 Gy and 23.2 % within the 40 Gy isodose lines. A significant decrease in thyroid volume was noted by 1-year post-treatment (p < 0.0001) and thereafter. By 4 years post-treatment, average thyroid volume was decreased by 29.7 % (range: 2.3–64.4 %). Thyroid volume receiving 40 Gy or higher demonstrated a greater decrease compared to those receiving lower irradiation dosage. HT occurred in 17 patients (27.9 %). Patients who developed HT displayed a larger decrease in the thyroid volume receiving between 20 and 40 Gy at 12 months (p = 0.033). ConclusionOur study demonstrates for the first time that a reduction in thyroid volume may be seen as early as 6 months after SCV-directed RT for breast cancer, which correlates with development of clinical and subclinical HT. Furthermore, a dose-dependent correlation exists between thyroid subvolume reduction and SCV-directed RT in breast cancer patients. As feasible, efforts should be made to reduce the dose to the thyroid in patients who undergo RNI for breast cancer.

Effectiveness of three exercise programs and intensive follow-up in improving quality of life, pain, and lymphedema among breast cancer survivors: a randomized, controlled 6-month trial

Postoperative complications of breast cancer (BC) seriously affect the quality of life (QOL) of survivors. Physical activity is related to prevention of complications and improvement of QOL. Follow-up can keep patients motivated to exercise. This study aimed to (1) compare the effect of three exercise programs on lymphedema, pain, and QOL in BC patients and (2) explore the effect of intensive follow-up on the outcomes of exercise programs. A single-blind randomized parallel controlled trial with a 6-month intervention was carried out in China in 2021. The study sample included 200 women with BC. The patients were randomly divided into 4 groups. G0 (control group) was joint mobility exercise (JME) group; G1 was joint mobility exercise + intensive follow-up (IF) group; G2 was JME + aerobic exercise (AE) + IF group; and G3 was JME + progressive resistance exercise (PRE) + IF group. Outcome measures were evaluated at baseline (T1), 3months post-intervention (T2), and 6months post-intervention (T3). The following instruments and measurements were administered before and after the intervention: the Functional Assessment of Cancer Therapy-Breast (FACT-B) instrument, the numerical rating scale (NRS), and the relative volume change (RVC). Verificating aim 1 is by comparing the results of G1, G2, and G3, and verificating aim 2 is achieved by comparing G0 and G1. Differences before and after the intervention were determined by analysis of variance of repeated measures and Kruskal-Wallis nonparametric analysis of variance. Among the exercise programs, JME + PRE + IF resulted in the best improvement in QOL (T2: ΔG3-G0 = 13.032, P = 0.008; T2: ΔG3-G1 = 13.066, P < 0.001; ΔG3-G0 = 17.379, P < 0.001). For pain relief, JME + AE + IF had the best improvement (T3: ΔG2-G1 = - 0.931, P = 0.010; ΔG2-G0 = - 1.577, P < 0.001). For the prevention of lymphedema, JME + AE + IF (Z = 2.651, P = 0.048) and JME + PRE + IF (Z = 3.277, P = 0.006) had the similar effect, but JME + PRE + IF is better than JME + AE + IF. JME + PRE have the best effect in improving the QOL and preventing lymphedema after surgery. In improving pain, the effect of JME + AE appears earlier, and the overall effect of JME + PRE is better. In addition, long-term and planned monitoring and follow-up are also important.

Early Referral for Breast-Cancer-Related Lymphedema: Do We Follow the Evidence? A Two-Year Prospective Multicenter Cohort Study

The early detection of breast-cancer-related lymphedema and referral for therapy has the potential to reduce lymphedema-related morbidity. Although research shows the benefits, a gap is observed between evidence and daily practice. We aimed to determine whether the early detection of lymphedema and referral for treatment is adequate following the current guidelines. Women with primary breast cancer treated with breast-conserving therapy or ablative treatment were included. Demographic-, general health-, tumor-, and treatment-related data were recorded. Bilateral arm volume measurements were performed preoperatively and 3, 6, 12, and 24 months post-surgery. A 5% or greater Relative Volume Change was considered the cutoff point for lymphedema and as an indication for therapy referral. After 24 months post-surgery, the main outcomes show that among the patients with early signs of lymphedema, based on a Relative Volume Change ≥5%, a nonreferral for therapy was noted in 83%. Additionally, we observed a significant improvement of the mean Relative Volume Change at 24 months within this group, which might implicate that nonreferral was an adequate choice and that watchful waiting is appropriate when lymphedema is detected within the first year post-surgery.

Prediction of left lobe hypertrophy after right lobe radioembolization of the liver using a clinical data model with external validation

In cirrhotic patients with hepatocellular carcinoma (HCC), right-sided radioembolization (RE) with Yttrium-90-loaded microspheres is an established palliative therapy and can be considered a “curative intention” treatment when aiming for sequential tumor resection. To become surgical candidate, hypertrophy of the left liver lobe to > 40% (future liver remnant, FLR) is mandatory, which can develop after RE. The amount of radiation-induced shrinkage of the right lobe and compensatory hypertrophy of the left lobe is difficult for clinicians to predict. This study aimed to utilize machine learning to predict left lobe liver hypertrophy in patients with HCC and cirrhosis scheduled for right lobe RE, with external validation. The results revealed that machine learning can accurately predict relative and absolute volume changes of the left liver lobe after right lobe RE. This prediction algorithm could help to estimate the chances of conversion from palliative RE to curative major hepatectomy following significant FLR hypertrophy.

Electrocardiogram Belt guidance for left ventricular lead placement and biventricular pacing optimization

Patients with ischemic cardiomyopathy, non-left bundle branch block, or QRS duration <150 ms have a lower response rate to cardiac resynchronization therapy (CRT) than did other indicated patients. The ECG Belt system (EBS) is a novel surface mapping system designed to measure electrical dyssynchrony via the standard deviation of the activation times of the left ventricle. The objectives of this study were to evaluate the efficacy of the EBS in patients less likely to respond to CRT and to determine whether EBS use in lead placement guidance and device programming was superior to standard CRT care. This was a prospective randomized trial of patients with heart failure and EBS-guided CRT implantation and programming vs standard CRT care. The primary end point was relative change in left ventricular end-systolic volume from baseline to 6 months postimplantation. A total of 408 patients from centers in Europe and North America were randomized. Although both patients with EBS and control patients had a mean improvement in left ventricular end-systolic volume, there was no significant difference in relative change from baseline (P = .26). While patients with a higher baseline standard deviation of the activation times derived greater left ventricular reverse remodeling, improvement in electrical dyssynchrony did not correlate with the extent of reverse remodeling. The findings of the present study do not support EBS-guided therapy for CRT management of heart failure with reduced ejection fraction.