Asymmetric Changes Research Articles

Greenland's firn responds more to warming than to cooling

Abstract. The porous layer of snow and firn on the Greenland Ice Sheet stores meltwater and limits the rate at which the ice sheet contributes to sea level rise. This buffer is threatened in a warming climate. To better understand the nature and timescales of firn's response to air temperature change on the Greenland Ice Sheet, we use a physics-based model to assess the effects of atmospheric warming and cooling on Greenland's firn air content in idealized climate experiments. We identify an asymmetric response of Greenland's firn to air temperature: firn loses more air content due to warming compared to the amount gained from commensurate cooling. 100 years after a 1 °C temperature perturbation, warming decreases the spatially integrated air content by 9.7 %, and cooling increases it by 8.3 %. In dry firn, this asymmetry is driven by the highly nonlinear relationship between temperature and firn compaction, as well as the dependence of thermal conductivity on the composition of the firn. The influence of liquid water accentuates this asymmetry. In wet firn areas, melt increases nonlinearly with atmospheric warming, thus enhancing firn refreezing and further warming the snowpack through increased latent heat release. Our results highlight the vulnerability of Greenland firn to temperature change and demonstrate that firn air content is more efficiently depleted than generated. This asymmetry in the temperature–firn relationship may contribute to the overall temporally asymmetric mass change of the Greenland Ice Sheet in a changing climate across many timescales.

Natural reversal of cavefish heart asymmetry is controlled by Sonic Hedgehog effects on the left-right organizer.

The direction of left-right visceral asymmetry is conserved in vertebrates. Deviations of the standard asymmetric pattern are rare, and the underlying mechanisms are not understood. Here, we use the teleost Astyanax mexicanus, consisting of surface fish with normal left-oriented heart asymmetry and cavefish with high levels of reversed right-oriented heart asymmetry, to explore natural changes in asymmetry determination. We show that Sonic Hedgehog (Shh) signaling is increased at the posterior midline, Kupffer's vesicle (the teleost left-right organizer) is enlarged and contains longer cilia, and the number of dorsal forerunner cells is increased in cavefish. Furthermore, Shh increase in surface fish embryos induces asymmetric changes resembling the cavefish phenotype. Asymmetric expression of the Nodal antagonist Dand5 is equalized or reversed in cavefish, and Shh increase in surface fish mimics changes in cavefish dand5 asymmetry. Shh decrease reduces the level of right-oriented heart asymmetry in cavefish. Thus, naturally occurring modifications in cavefish heart asymmetry are controlled by the effects of Shh signaling on left-right organizer function.

Does Urbanization Exacerbate Asymmetrical Changes in Precipitation at Divergent Time Scales in China?

AbstractUrbanization alters the thermal and dynamic environment of the local climate system, resulting in significant impacts on precipitation in both urban and adjacent areas. Nevertheless, there remains a significant gap in our understanding of urbanization‐induced effects on asymmetrical, symmetrical, and other precipitation patterns in urban agglomerations (UAs) with divergent background climates and geographic regions at different timescales. Specifically, this asymmetrical change pattern is characterized by an increase in heavy (or light) rainfall and a decrease in light (or heavy) rainfall. Here, we assessed the effects of urbanization on precipitation patterns across 18 UAs situated in diverse background climates and geographical areas in China at different timescales. The results demonstrate that urbanization predominantly alters precipitation patterns in UAs located in the humid region. Specifically, urbanization amplified asymmetrical changes in Yangtze River Delta, Pearl River Delta, Beibu Gulf, Middle Yangtze River, and Guanzhong, but exacerbated symmetrical changes in precipitation in some regions such as Chengdu‐Chongqing. Notably, the urbanization effect demonstrates greater significance at the hourly scale, as exemplified in the Yangtze River Delta, Pearl River Delta, and Middle Yangtze River, where the urban impact is nearly twice as pronounced when compared to the daily scale. Moreover, urbanization had either no effect or has a negative impact on precipitation patterns in UAs located within continental and arid regions. This is related to the intensity of urbanization, background climate and complex topography. This finding implies that urban managers should consider the impact of urbanization on precipitation patterns in different contexts to provide scientific guidance for urban planning.

Interocular asymmetry of retinal change in Parkinson's disease

PurposeTo investigate interocular asymmetry (IA) of retinal structure and vessel density in patients with Parkinson's disease (PD) and normal controls (NC). MethodsSeventy-eight subjects including 40 PD patients and 38 NC had completed optical coherence tomography angiography (OCTA) and neurological examinations for three rating scales (UPDRS-III, MMSE and MoCA). The IA was calculated by the absolute value of difference in right and left eyes. The IA of thickness in macular ganglion cell inner-plexiform layer (GCIPL), peripapillary retinal nerve fiber layer (pRNFL), and vessel density of superficial capillary plexus (SCP), deep capillary plexus (DCP), radial peripapillary capillary (RPC) were obtained from OCTA. ResultsThe motor-symptom-onset side of eyes showed lower vessel density in parafovea of SCP (51.09 ± 3.46 vs 49.81 ± 4.16, P = 0.03) and superior hemi of perifovea DCP (49.55 ± 5.81 vs 47.33 ± 5.71, = 0.04). The PD patients showed larger IA in thickness of superior half of pRNFL (5.27 [2.67, 10.87] vs 3.08 [1.62, 5.61], P = 0.02) and parafovea GCIPL (2.40[1.25, 6.35] vs 1.40[0.50, 2.45], P = 0.02). No significant interocular asymmetry was found in vessel density between PD and NC. A higher UPDRS-III scale was associated with larger IA in GCIPL (β = 0.093, P = 0.001) and smaller IA in DCP (β = −0.065, P = 0.037). ConclusionThe motor-symptom-onset side of eyes showed more severe loss of macular vessel density than the other side of eyes. The PD patients showed asymmetrical structural change in GCIPL and pRNFL, which showed the potential as the diagnostic biomarker for PD.

Asymmetrical changes of electron-donating and electron-accepting capacities of natural organic matter during its interaction with Fe oxyhydroxides

The electron gain and loss of natural organic matter (NOM) plays an important role in the biogeochemical cycling of element and contaminant attenuation. The electron-donating capacity (EDC) and electron-accepting capacity (EAC) of NOM determine its electron exchange ability. However, the influences of bonded matrices on EDC and EAC of NOM remain unclear. Here we investigated the variations in EDC and EAC of NOM during its interaction with Fe oxyhydroxides. Compared to original NOM, the presence of Fe oxyhydroxides slightly decreased the EDC of dissolved NOM by 0.58–2.08 mmol e−/g C and of adsorbed NOM by 0.33–2.67 mmol e−/g C. However, the EAC of dissolved NOM and adsorbed NOM significantly (p < 0.05) increased by 1.92–14.17 and 3.08–36.67 mmol e−/g C, respectively. The excessive increase of EAC was mainly attributed to changes in NOM chemical components, particularly increases in oxidative components such as Fe(III) and quinonoid carbonyls, rather than changes in EDC. For dissolved NOM, the heightened EAC was mainly attributed to the complexation of Fe(III) by carboxyl in NOM. For adsorbed NOM, the boosted EAC was predominantly linked to the enrichment of quinonoid carbonyl through the selective molecular fractionation and the oxidative polymerization of polyphenols in NOM. Our finding highlights the previously overlooked phenomenon of asymmetrical changes of EDC and EAC of NOM during its interaction with Fe oxyhydroxides. The increased EAC could potentially affect various biogeochemical processes, such as methane production, anaerobic ammonium oxidation and microbial Fe(III) reduction.

Asymmetric fin shape changes swimming dynamics of ancient marine reptiles’ soft robophysical models

Animals have evolved highly effective locomotion capabilities in terrestrial, aerial, and aquatic environments. Over life’s history, mass extinctions have wiped out unique animal species with specialized adaptations, leaving paleontologists to reconstruct their locomotion through fossil analysis. Despite advancements, little is known about how extinct megafauna, such as the Ichthyosauria one of the most successful lineages of marine reptiles, utilized their varied morphologies for swimming. Traditional robotics struggle to mimic extinct locomotion effectively, but the emerging soft robotics field offers a promising alternative to overcome this challenge. This paper aims to bridge this gap by studying Mixosaurus locomotion with soft robotics, combining material modeling and biomechanics in physical experimental validation. Combining a soft body with soft pneumatic actuators, the soft robotic platform described in this study investigates the correlation between asymmetrical fins and buoyancy by recreating the pitch torque generated by extinct swimming animals. We performed a comparative analysis of thrust and torque generated by Carthorhyncus, Utatsusaurus, Mixosaurus, Guizhouichthyosaurus, and Ophthalmosaurus tail fins in a flow tank. Experimental results suggest that the pitch torque on the torso generated by hypocercal fin shapes such as found in model systems of Guizhouichthyosaurus, Mixosaurus and Utatsusaurus produce distinct ventral body pitch effects able to mitigate the animal’s non-neutral buoyancy. This body pitch control effect is particularly pronounced in Guizhouichthyosaurus, which results suggest would have been able to generate high ventral pitch torque on the torso to compensate for its positive buoyancy. By contrast, homocercal fin shapes may not have been conducive for such buoyancy compensation, leaving torso pitch control to pectoral fins, for example. Across the range of the actuation frequencies of the caudal fins tested, resulted in oscillatory modes arising, which in turn can affect the for-aft thrust generated.

Structural basis for inhibition of the lysosomal two-pore channel TPC2 by a small molecule antagonist

Two pore channels are lysosomal cation channels with crucial roles in tumor angiogenesis and viral release from endosomes. Inhibition of the two-pore channel 2 (TPC2) has emerged as potential therapeutic strategy for the treatment of cancers and viral infections, including Ebola and COVID-19. Here, we demonstrate that antagonist SG-094, a synthetic analog of the Chinese alkaloid medicine tetrandrine with increased potency and reduced toxicity, induces asymmetrical structural changes leading to a single binding pocket at only one intersubunit interface within the asymmetrical dimer. Supported by functional characterization of mutants by Ca2+ imaging and patch clamp experiments, we identify key residues in S1and S4 involved in compound binding to the voltage sensing domain II. SG-094 arrests IIS4 in a downward shifted state which prevents pore opening via the IIS4/S5 linker, hence resembling gating modifiers of canonical VGICs. These findings may guide the rational development of new therapeutics antagonizing TPC2 activity.

Unilateral high-riding vertebral artery is associated with asymmetric morphological changes of the atlantoaxial joint: a novel risk factor for atlantoaxial osteoarthritis.

This study aimed to investigate the association between unilateral high-riding vertebral artery (HRVA) and morphological changes in the atlantoaxial joint (AAJ) and to determine whether unilateral HRVA is a risk factor for atlantoaxial osteoarthritis (AAOA). We conducted a retrospective analysis of 2496 patients admitted to our medical center between January 2020 and December 2022 who underwent CT imaging of the cervical spine. Two hundred and seventy-two patients with unilateral HRVA (HRVA group) were identified and a respective 2:1 age- and sex-matched control group without HRVA was built. Morphological parameters, including C2 lateral mass settlement (C2 LMS), C1/2 coronal inclination (C1/2 CI), lateral atlanto-dental interval (LADI), and C1/2 relative rotation angle (C1/2 RRA) were measured. The degree of AAOA was recorded. Risk factors associated with AAOA were identified using univariate and multivariable logistic regression analyses. The study included 61.4% women, and the overall average age of the study population was 48.7years. The morphological parameters (C2 LMS, C1/2 CI, and LADI) in AAJ were asymmetric between the HRVA and the non-HRVA sides in the HRVA group (p < 0.001). These differences in parameters (d-C2 LMS, d-C1/2 CI, and d-LADI) between the HRVA and the non-HRVA sides, and C1/2 RRA were significantly larger than those in the control group. Eighty-three of 816 patients (10.2%) with AAOA had larger values of d-C2 LMS, d-C1/2 CI, d-LADI, and C1/2 RRA compared with the patients without AAOA (p < 0.05). The multivariable logistic regression analysis indicated that unilateral HRVA [adjusted odds ratio (OR) = 2.6, 95% CI: 1.1-6.3, p = 0.029], age in the sixth decade or older (adjusted OR = 30.2, 95% CI: 16.1-56.9, p < 0.001), women (adjusted OR = 2.1, 95% CI: 1.0-5.6, P = 0.034) were independent risk factors for AAOA. Unilateral HRVA was associated with asymmetric morphological changes of nonuniform settlement of C2 lateral mass, lateral slip of atlas, and atlantoaxial rotation displacement. Besides age ≥ 60years and females, unilateral HRVA is an independent risk factor for AAOA.

Model refinements with experimental validation in piezoelectric plate actuators

The axisymmetric vibration analysis of circular plates with piezoelectric layers and step changes in plate thickness is conducted. For the chosen configurations, it is necessary to solve a coupled system of differential equations for extensional and flexural vibration to obtain accurate modal results. The adopted computational approach is based upon the classical transfer matrix method. Instead of employing analytical solutions in the form of e.g. Bessel functions, matrix exponentials of the system matrix are directly computed in the transfer matrices for finding highly accurate solutions. The developed approach has enabled the complete quantitative modal analysis in piezoelectric actuators. The procedure is firstly verified against available analytical results for natural frequencies and modes shapes in circular homogeneous plates, and by using finite element simulations for plates with asymmetric step changes in thickness. Ultimately, the developed approach is validated against experimental results of relevance to applications in piezoelectric synthetic jet actuation. The obtained numerical results for modal parameters and frequency response functions are in excellent agreement with the available analytical results, and with previous and newly presented in the paper experimental data, when considering the inherent uncertainty in parameter values. Based on extensive experimental results, realistic damping is introduced in the model of piezoelectric plate actuators. Importantly, it is shown that solutions of high accuracy can be obtained by a more general coordinate system than that traditionally linked to the plate neutral plane(s).

Can Asymmetric Punishment Explain Norm Changes?

Abstract: We test a general theory of norm changes based on evidence that people will punish less hygienic others more strongly than more hygienic others. The theory concludes that such asymmetric punishment would result in hygiene norms becoming ever stricter. We argue that, because complaints about one’s behavior might lead to protest, norms might not always change because of such complaints. We conducted an online experiment ( N = 1,023 Swiss adults) using handwashing as the target behavior. We replicated the asymmetry in punishment intensities and found that the intensity of protests against complaints about one’s too unhygienic behavior approached the intensity of these complaints. We conclude that, while asymmetric punishment may drive norm change, protests may lead to norm stability.

Longitudinal attenuation in political polarization: Evidence from COVID-19 vaccination adherence in Brazil

BackgroundWhile political polarization in policy opinions, preferences, and observance is well established, little is known about whether and how such divisions evolve, and possibly attenuate, over time. Using the COVID-19 pandemic in Brazil as the backdrop, we examine the longitudinal evolution of a highly relevant and polarizing policy: adherence to the COVID-19 vaccination. MethodsStudies 1 (N = 3346) and 2 (N = 10,214) use nationwide surveys to document initial differences and subsequent changes in vaccination adherence between conservatives ("Bolsonaristas") and non-conservatives ("non-Bolsonaristas"). Study 3 (N = 742) uses an original dataset to investigate belief changes among conservatives and their association with asymmetric changes in vaccination adherence. ResultsDespite substantial differences at the early stages of rollout, the gap in vaccination adherence between conservatives and non-conservatives significantly decreased with the passage of time, driven essentially by a much faster uptake among the initially most skeptic—the conservatives. Study 3 demonstrates that the asymmetric changes in vaccination adherence were associated with meaningful belief changes among the conservatives, especially about the perceived effectiveness of the COVID-19 vaccines and the expected adherence of peers to the vaccination campaign. ConclusionsTogether, these studies show that, in a context where the superiority of the promoted policy becomes clear over time and individuals have the opportunity to revisit prior beliefs, even intense political polarization can be attenuated.

The Phenotypic and Genotypic Spectrum of CSF1R-Related Disorder in China.

Colony-stimulating factor 1 receptor (CSF1R)-related disorder (CRD) is a rare autosomal dominant disease. The clinical and genetic characteristics of Chinese patients have not been elucidated. The objective of the study is to clarify the core features and influence factors of CRD patients in China. Clinical and genetic-related data of CRD patients in China were collected. Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and Sundal MRI Severity Score were evaluated. Whole exome sequencing was used to analyze the CSF1R mutation status. Patients were compared between different sexes, mutation types, or mutation locations. A total of 103 patients were included, with a male-to-female ratio of 1:1.51. The average age of onset was (40.75 ± 8.58). Cognitive impairment (85.1%, 86/101) and parkinsonism (76.2%, 77/101) were the main clinical symptoms. The most common imaging feature was bilateral asymmetric white matter changes (100.0%). A total of 66 CSF1R gene mutants (22 novel mutations) were found, and 15 of 92 probands carried c.2381 T > C/p.I794T (16.30%). The MMSE and MoCA scores (17.0 [9.0], 11.90 ± 7.16) of female patients were significantly lower than those of male patients (23.0 [10.0], 16.36 ± 7.89), and the white matter severity score (20.19 ± 8.47) of female patients was significantly higher than that of male patients (16.00 ± 7.62). There is no statistical difference in age of onset between male and female patients. The core manifestations of Chinese CRD patients are progressive cognitive decline, parkinsonism, and bilateral asymmetric white matter changes. Compared to men, women have more severe cognitive impairment and imaging changes. c.2381 T > C/p.I794T is a hotspot mutation in Chinese patients. © 2024 International Parkinson and Movement Disorder Society.

Interference effect and Raman depolarization behavior in MoO2 bubbles

Here, MoO2 bubbles are firstly found in MoO2 nanosheets (NSs) synthesized by chemical vapor deposition and exposed to air for 2–3 years. Interestingly, the Newton’s rings are clearly observed in Raman map of MoO2 bubbles. Meanwhile, it’s found that the height of bright rings close to the 1/2, 2/2, 3/2 of the laser wavelength, confirming that the Newton’s rings in Raman map are caused by the laser interference on the surface of bubbles. At the same time, based on simple membrane theory, the adhesion energy 0.15 and 1.08 J/m2 between MoO2 NSs and different SiO2/Si substrates are extracted. Moreover, Raman depolarization effect is observed on the surface of MoO2 bubbles. As the aspect ratio of bubbles increases from 0.16 to 0.21, the relative-depolarization ratios of 205 cm−1 and 750 cm−1 phonon modes are gradually increased from 18% to 46% and 10–36%, respectively. The Raman depolarization behavior should be ascribed to the surface strain of MoO2 bubbles leading to the asymmetric changes of photoelastic tensor in all directions of the crystal. This finding maybe provides a reference for regulating the polarization characteristics of MoO2 by adjusting its surface strain and ultimately achieving application in the field of photonics.

Asymmetric changes in foot anthropometry with pregnancy may be related to onset of lower limb and low back pain.

Fifty percent of pregnant females experience pain with 20% reporting long-term pain post-partum. Pregnant females undergo changes in foot anthropometry, lower extremity alignment, and joint laxity. It is unknown if asymmetric alterations may be related to development of pain. The purpose of this study was twofold: 1) to compare asymmetric alignment in pregnant females with and without pain during pregnancy and in nulliparous controls and 2) to assess the relationship between asymmetric alignment and pain severity in all participants. Ten pregnant females in their third trimester and nine nulliparous controls participated. Bilateral asymmetry of foot length, width, arch index, arch height index, arch rigidity index, arch drop, rearfoot angle, and pelvic obliquity were determined. Joint laxity and musculoskeletal pain were also assessed. ANOVAs were utilized to compare asymmetries between pregnant females reporting pain (n = 5), those not reporting pain (n = 5), and controls. Spearman's Rho correlations were used to relate asymmetry to pain magnitude (α = 0.05). No statistical differences (p>0.05) were found between pregnant females with or without pain and controls for any of the metrics. Negative correlations were found between arch index asymmetry and low back pain (p = 0.005), foot length asymmetry and lower leg pain (p = 0.008), and pelvic obliquity and lower leg pain (p = 0.020). Positive correlations were found between foot width asymmetry and knee pain (p = 0.028), as well as arch drop asymmetry and upper leg (p = 0.024), knee (p = 0.005), and lower leg pain (p = 0.019). This study was successful in identifying potential targets for prevention and treatment of pain in pregnancy. Furthermore, because pain during pregnancy may be predictive of pain post-partum, it is important to conduct future research to determine both if interventions such as footwear or exercise can prevent or treat these asymmetries and prevent post-partum pain.

Prices versus quantities in forest regulation

We revisit an unanswered and yet critical question in forest policy design: does a price or quantity instrument achieve a better social outcome when the government does not have perfect information. This is a common question in environmental regulation, but in the forest policy literature an equivalence between these instruments has historically been presented, albeit under perfect information. In the forestry case one might be tempted to simply defer to Weitzman (1974), who derived rules for prices versus quantity policy choices when either marginal abatement costs or marginal benefits of polluting emissions are unknown to the policy maker. These rules may not be transferrable to the forestry problem, however. We develop a framework of marginal costs and benefits based on a standard rotation model, showing that uncertainty leads to (very) different results than in the emissions literature. For example, we find that the slopes of marginal costs and benefits and the difference between the expected values of uncertain parameters and their realizations matter differently for the forest policy case. We also find that symmetric over- and under-estimation around true parameter values can result in asymmetric changes in marginal cost curves. Most importantly, we find that even the size of this difference now matters to the price versus quantity policy choice. Our results both draw into question whether Weitzman rules simply apply to forest resources, and they suggest that our new approach should be used for evaluating alternative forestry policies to achieve public goods goals.

Asymmetric expression of PIEZO2 in paraspinal muscles of adolescent idiopathic scoliosis.

Muscle imbalance has long been recognized as one of the possible pathogeneses for adolescent idiopathic scoliosis (AIS). PIEZO2, the susceptibility gene of AIS, has been identified to play an important role in neuromuscular activities. This study aims to compare the mRNA expression of PIEZO2 between concave and convex paraspinal muscles of AIS patients and to identify the relationship between the ratio of PIEZO2 expression and curve magnitude. Twenty female AIS patients (right thoracic curve) who underwent spinal correction surgery were divided into moderate (n= 12) and severe (⩾ 70 degrees) curve groups (n= 8). The morphology of the paraspinal muscles was assessed with spinal MRI. Multifidus specimens were collected during surgical operations from the concave and convex sides of the apical region, and mRNA expression of the PIEZO2 gene was compared between sides. The localization of PIEZO2 protein expression was confirmed with the markers PAX7 and PAX3, and the percentage of PIEZO2+ cells was also investigated. In the moderate curve group, fatty infiltration in the deep paraspinal muscle was significantly higher on the concave side than on the convex side. There were no differences in deep muscle area, superficial muscle area, or fatty infiltration of superficial paraspinal muscle. The mRNA expression of PIEZO2 was significantly increased on the concave side, and the asymmetric expression predominantly occurred in moderate curves rather than severe ones. PIEZO2 was expressed on satellite cells instead of fibers of the muscle spindle. The percent of PIEZO2+PAX7+ cells in myofibers was significantly higher on the concave side in the moderate curve group, but not in the severe curve group. Asymmetric morphological changes occur in the deep paraspinal muscles of AIS. The PIEZO2 is asymmetrically expressed in the multifidus muscle and is preferentially expressed in satellite cells.

Asymmetric contribution of a selectivity filter gate in triggering inactivation of CaV1.3 channels.

Voltage-dependent and Ca2+-dependent inactivation (VDI and CDI, respectively) of CaV channels are two biologically consequential feedback mechanisms that fine-tune Ca2+ entry into neurons and cardiomyocytes. Although known to be initiated by distinct molecular events, how these processes obstruct conduction through the channel pore remains poorly defined. Here, focusing on ultrahighly conserved tryptophan residues in the interdomain interfaces near the selectivity filter of CaV1.3, we demonstrate a critical role for asymmetric conformational changes in mediating VDI and CDI. Specifically, mutagenesis of the domain III-IV interface, but not others, enhanced VDI. Molecular dynamics simulations demonstrate that mutations in distinct selectivity filter interfaces differentially impact conformational flexibility. Furthermore, mutations in distinct domains preferentially disrupt CDI mediated by the N- versus C-lobes of CaM, thus uncovering a scheme of structural bifurcation of CaM signaling. These findings highlight the fundamental importance of the asymmetric arrangement of the pseudotetrameric CaV pore domain for feedback inhibition.

Evaluation of cortical thickness and volume differences of the cerebellum in Parkinson's cases

Parkinson's disease (PD) is the most common neurodegenerative disease after Alzheimer's disease. PD causes degenerative changes in the cerebellum. It is known that the cerebellum does not have a symmetrical anatomy and some pathological disorders may cause asymmetric changes in the cerebellum. In this study, our aim is evaluate whether or not cases with PD show age and gender dependent cerebellar changes and cerebellar asymmetry comparing with healthy subjects. We also aimed to depict the probable cortical thickness differences in cases with PD by using a stereological technique. The study evaluated the volumetric assesment of each cortical cerebellar hemisphere and total cerebellum by applying a stereological technique on magnetic resonance images. The age and gender-matched study was composed of 47 adult cases with PD and 47 healthy subjets as control. In the PD group, right and left cerebellar hemisphere volume, total cerebellum volume, and cortical thickness of the right and left cerebellar hemispheres were significantly lower than the control group (p&lt;0.01). Although there was significant cerebellar atrophy and asymmetry in PD cases with age between 40-71, the study showed no statistically significant cerebellar asymmetry in cases over 70 years of age. However, no significant difference was detected depending on gender. Our findings suggest that in PD, cerebellum’s cortical thickness and volume decreases. The decrease in the volume and cortical thickness of the cerebellum increases with age, regardless of gender, compared to healthy individuals. However, this difference begins to close with age.

Evaluation of 2D ion chamber arrays for patient specific quality assurance using a static phantom at a 0.35 T MR-Linac

IntroductionPatient specific quality assurance (QA) in MR-Linacs can be performed with MR-compatible ion chamber arrays. However, the presence of a static magnetic field can alter the angular response of such arrays substantially. This works investigates the suitability of two ion chamber arrays, an air-filled and a liquid-filled array, for patient specific QA at a 0.35 T MR-Linac using a static phantom. MethodsIn order to study the angular response, the two arrays were placed in a static, solid phantom and irradiated with 9.96 × 9.96 cm2 fields every 10° beam angle at a 0.35 T MR-Linac. Measurements were compared to the TPS calculated dose in terms of gamma passing rate and relative dose to the central chamber. 20 patient specific quality assurance plans were measured using the liquid-filled array. ResultsThe air-filled array showed asymmetric angular response changes of central chamber dose of up to 18% and down to local 3 mm / 3% gamma rates of 20%, while only minor differences within 3% (excluding parallel irradiation and beams through the couch edges) were found for the liquid-filled ion chamber array without rotating the phantom. Patient plan QA using the liquid-filled array yielded a median local 3 mm / 3% 3D gamma passing rate of 99.8% (range 96.9%–100%) ConclusionA liquid-filled ionization chamber array in combination with a static phantom can be used for efficient patient specific plan QA in a single measurement set-up in a 0.35 T MR-Linac, while the air-filled ion chamber array phantom shows large angular response changes and has its limitations regarding patient specific QA measurements

On the Flexible Neo-Normal MSAR MSN-Burr Control Chart in Air Quality Monitoring

Air quality significantly influences human health and the environment, necessitating a robust monitoring to detect abnormalities. This paper aims to develop a new model to accurately capture air quality data’s structural changes and asymmetrical patterns. We introduce the neo-normal Markov Switching Autoregressive (MSAR) Modified Skew Normal Burr (MSN-Burr) model, called neo-normal MSAR MSN-Burr. This model extends the MSAR normal framework, handling symmetrical and asymmetrical patterns in air quality data. The MSN-Burr distribution is employed for accurate estimation of skewed and symmetric data. The model efficiency is demonstrated through simulation studies generating symmetric data with normal, double exponential, and Student- t distributions, followed by application to real air quality data using Stan language. The proposed model successfully adapts to asymmetric structural changes, as evidenced by creating the Highest Posterior Distribution (HPD) for upper and lower limits. The model identifies two regimes representing normal and abnormal air quality conditions, with modes of 8 and 19 µg/m3, respectively. The MSAR-MSN-Burr model exhibits a 32.27% RMSE improvement in simulations and a 16.4% RMSE improvement in real air quality data over the normal-MSAR model. The proposed neo-normal MSAR MSN-Burr model is significantly enhancing the accuracy of air quality monitoring, providing a more efficient tool for detecting air quality abnormalities.