Multiplicative Inverse Research Articles

Joint inversion of gravity and gravity gradient data: A systematic evaluation

Gravity and gravity gradiometry measurements are commonly used to map density variations in the subsurface. Gravity measurements can characterize gravitational anomalies at long and short wavelengths effectively, but the cost of collecting a sufficiently spatially dense survey to characterize the short wavelengths can be prohibitive. Gravity gradient data can be quickly collected with short-wavelength information at a low noise level, but they have decreasing sensitivity to longer wavelengths. We have described a method to jointly invert gravity and gravity gradient data that takes advantage of the differing frequency contents and noise levels of the two methods to create an improved image of the subsurface. Previous work treated the inversion as a multiple component gravity inversion; however, this can cause unintended errors in the recovered models because each data set is not guaranteed to be fit within its noise level. Our joint inversion methodology ensures that the gravity and gravity gradient data sets are fit within their individual noise levels by incorporating a relative weighting parameter, and we describe how to find that parameter. This method can also be used to create an improved broadband gravity anomaly map that has a reduced noise level at long wavelengths using a joint equivalent source reconstruction. We first build a synthetic model using a Minecraft world editor that has different wavelength anomalies, and find the improvement with joint inversion. These results are also confirmed using a real-world example at the R. J. Smith test range in Kauring, Australia.

Optimizing EEG Source Reconstruction with Concurrent fMRI-Derived Spatial Priors

Reconstructing EEG sources involves a complex pipeline, with the inverse problem being the most challenging. Multiple inversion algorithms are being continuously developed, aiming to tackle the non-uniqueness of this problem, which has been shown to be partially circumvented by including prior information in the inverse models. Despite a few efforts, there are still current and persistent controversies regarding the inversion algorithm of choice and the optimal set of spatial priors to be included in the inversion models. The use of simultaneous EEG-fMRI data is one approach to tackle this problem. The spatial resolution of fMRI makes fMRI derived spatial priors very convenient for EEG reconstruction, however, only task activation maps and resting-state networks (RSNs) have been explored so far, overlooking the recent, but already accepted, notion that brain networks exhibit dynamic functional connectivity fluctuations. The lack of a systematic comparison between different source reconstruction algorithms, considering potentially more brain-informative priors such as fMRI, motivates the search for better reconstruction models. Using simultaneous EEG-fMRI data, here we compared four different inversion algorithms (minimum norm, MN; low resolution electromagnetic tomography, LORETA; empirical Bayes beamformer, EBB; and multiple sparse priors, MSP) under a Bayesian framework (as implemented in SPM), each with three different sets of priors consisting of: (1) those specific to the algorithm; (2) those specific to the algorithm plus fMRI task activation maps and RSNs; and (3) those specific to the algorithm plus fMRI task activation maps and RSNs and network modules of task-related dFC states estimated from the dFC fluctuations. The quality of the reconstructed EEG sources was quantified in terms of model-based metrics, namely the expectation of the posterior probability P(model|data) and variance explained of the inversion models, and the overlap/proportion of brain regions known to be involved in the visual perception tasks that the participants were submitted to, and RSN templates, with/within EEG source components. Model-based metrics suggested that model parsimony is preferred, with the combination MSP and priors specific to this algorithm exhibiting the best performance. However, optimal overlap/proportion values were found using EBB and priors specific to this algorithm and fMRI task activation maps and RSNs or MSP and considering all the priors (algorithm priors, fMRI task activation maps and RSNs and dFC state modules), respectively, indicating that fMRI spatial priors, including dFC state modules, might contain useful information to recover EEG source components reflecting neuronal activity of interest. Our main results show that providing fMRI spatial derived priors that reflect the dynamics of the brain might be useful to map neuronal activity more accurately from EEG-fMRI. Furthermore, this work paves the way towards a more informative selection of the optimal EEG source reconstruction approach, which may be critical in future studies.

Frequency and clinical significance of chromosomal inversions prenatally diagnosed by second trimester amniocentesis

To compare the frequency and clinical significance of familial and de novo chromosomal inversions during prenatal diagnosis. This was a retrospective study of inversions diagnosed prenatally in an Asian population by applying conventional GTG-banding to amniocyte cultures. Data from 2005 to 2019 were extracted from a single-center laboratory database. The types, frequencies, and inheritance patterns of multiple inversions were analyzed. Pericentric variant inversions of chromosome 9 or Y were excluded. In total, 56 (0.27%) fetuses with inversions were identified in the 15-year database of 21,120 confirmative diagnostic procedures. Pericentric and paracentric inversions accounted for 62.5% (35/56) and 37.5% of the inversions, respectively. Familial inversions accounted for nearly 90% of cases, and de novo mutation was identified in two pericentric and two paracentric cases. Inversions were most frequently identified on chromosomes 1 and 2 (16.1% of all inversions), followed by chromosomes 6, 7, and 10 (8.9% of all cases). The indications for invasive testing were as follows: advanced maternal age (67.3%), abnormal ultrasound findings (2.1%), abnormal serum aneuploidy screening (20.4%), and other indications (10.2%). The mode of inheritance was available for 67.9% of cases (38/56), with 89.5% of inversions being inherited (34/38). A slight preponderance of inheritance in female fetuses was observed. Three patients with inherited inversions opted for termination (two had severe central nervous system lesions and one had thalassemia major). Gestation continued for 53 fetuses, who exhibited no structural defects at birth or significant developmental problems a year after birth. Our study indicates that approximately 90% of prenatally diagnosed inversions involve familial inheritance, are spreading, and behave like founder effect mutations in this isolated population on an island. This finding can help to alleviate anxiety during prenatal counseling, which further underscores the importance of parental chromosomal analysis, further genetic studies, and appropriate counseling in cases where a nonfamilial inversion is diagnosed.

The 2021 South Sandwich Island Mw 8.2 Earthquake: A Slow Event Sandwiched Between Regular Ruptures

AbstractWe determined the rupture sequence of the 12 August 2021 Mw 8.2 South Sandwich Island earthquake which appears to be a complex sequence in both time and space. Notable tsunamis were recorded by tide gauges at global distances. Given the complexity of this event, we conducted a multiple subevent inversion on broadband seismograms, to resolve its complex variations of fault geometry, location, depth, and temporal characteristics. We found that the rupture initiated as a regular deep thrust earthquake; it then ruptured shallower and triggered a silent and dominantly slow subevent extending ∼200 km to the south, and ended with two other regular subevents. The total duration is ∼260 s, unusually long for an Mw 8.2 event. Our result is qualitatively consistent with other moment tensor solutions and the deviant mB–Mw and MS–Mw relations, and provides a more quantitative space‐temporal pattern of this unusual sequence.

Ta2NiSe5 : A candidate topological excitonic insulator with multiple band inversions

The electronic structures and topological properties of the orthorhombic and monoclinic phases of the quasi-one-dimensional excitonic insulator Ta2NiSe5 are investigated based on density functional theory. In contrast to a single parity or band inversion across the Fermi level in many topological insulators studied previously, there are multiple parity and band inversions with or without spin-orbit coupling in both phases of Ta2NiSe5, resulting in more complex and topologically nontrivial electronic structures. The Dirac cone type surface states of the low-temperature monoclinic phase are also obtained. In this paper, we demonstrate that Ta2NiSe5 is a promising candidate as a three-dimensional topological excitonic insulator.

Arithmetic Addition Coding and Linear Invertible Equation using Prime Modulo with Multiplicative Inverse for Text Encryption

Arithmetic Addition Coding and Linear Invertible Equation using Prime Modulo with Multiplicative Inverse for Text Encryption

VLSI Architecture of S-Box With High Area Efficiency Based on Composite Field Arithmetic

This work aims at optimizing the hardware implementation of the SubBytes and inverse SubBytes operations in the advanced encryption standard (AES). To this, the composite field arithmetic (CFA) is employed to optimize all building blocks in S-box (and inverse S-box) of SubBytes (and inverse SubBytes) transformation. A joint design of S-box and inverse S-box is also proposed to further enhance the area efficiency. Specifically, the area of multiplier in the Galois composite field, GF <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$((2^{2})^{2})$ </tex-math></inline-formula> , is reduced. The squaring and multiplication with constant <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> in GF <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$((2^{2})^{2})$ </tex-math></inline-formula> are combined and optimized as well. Moreover, the multiplicative inversion in GF <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$((2^{2})^{2})$ </tex-math></inline-formula> is manually optimized. Furthermore, the S-box and inverse S-box are combined and optimized using the pre_processing and post_processing modules. To increase the throughput, a balanced and pipelined architecture is derived. Using the proposed architecture, a throughput of 5.79 Gbps for the S-box can be achieved on Virtex-6 XC6VLX240T and 10% better than the conventional work. According to the ASIC implementation result, the proposed design can still achieve the highest area efficiency and approximately 30% better than conventional works using TSMC 90nm process.

Creation of a new Drosophila melanogaster X chromosome balancer, First Multiple 8 ( FM8 ), using the CRISPR/Cas9 gene-editing system.

Balancer chromosomes contain multiple inversions that work to suppress crossing over and prevent recovery of most recombinant chromosomes, allowing for alleles to be kept long-term without selection. These balancers are incredible tools, but some alleles within larger inverted segments are still lost to rare double crossover events between the balanced and balancer chromosomes. This study details a new methodology of producing balancer chromosomes using CRISPR/Cas9 gene editing technology to create new inversions within the largest segment of the common X chromosome balancer, FM7c. We were able to create a new X chromosome balancer, FM8, and anticipate that this process can be used to not only create other balancers in Drosophila melanogaster, but other model organisms as well.

SLC38A8 mutation spectrum in foveal hypoplasia

AbstractPurposeSignificant phenotypic overlap exists between ocular albinism and SLC38A8 related foveal hypoplasia (FH) which hinders differential diagnosis. To facilitate molecular testing, we catalogued the spectrum of known pathogenic variants in SLC38A8 responsible for FH.MethodsThe UK 100 000 genomes (100KG) datasets were analysed to detect pathogenic SLC38A8 variants compatible with recessive inheritance in cases with phenotypes reminiscent of FH. Published literature was accessed to capture deleterious variants reported in FH affected families. Additional variants identified locally were incorporated for bioinformatic analysis. Variant interpretation included in‐silico pathogenicity assessment, population data and protein modelling.ResultsIn total, 41 pathogenic variants in SLC38A8 have been identified in 51 FH families; 17 missense, 4 splice site, 2 in‐frame deletions, 6 frameshift, 6 nonsense, 4 large deletions, a multiple exon inversion and a whole gene deletion. Nonsense variants are evenly distributed throughout the gene and protein, while missense variants are more likely to reside in transmembrane domains. 38 SLC38A8 variants were reported in the literature and we have identified 3 novel and 2 known variants in 4 families derived from the 100KG datasets and our local cohort. In one patient, a novel g.84049578_84060679inv (GRCh37) was detected in a homozygous state. Another harboured novel variant c.922_923insTG, p.(Thr308Metfs*14) and c.922A&gt;G, p.(Thr308Ala). Other homozygous variants include c.848A&gt;C, p.(Asp283Ala) and novel variant c.77C&gt;T, p.(Ser26leu). Protein modelling of SLC38A8 predicted a destabilising effect by both p.(Ser26leu) and p.(Thr308Ala). Haplotype analysis of Pakistani, Bangladeshi and Indian patients harbouring c.264C&gt;G, p.(Tyr88*) suggest a South Asian founder effect.ConclusionsWe reviewed and extended the spectrum of SLC38A8 variants causative for FH. The presence of multiple nonsense variants and in‐silico modelling of missense variants suggests a complete loss of function as the likely disease mechanism.

Low-Complexity Detectors for Uplink Massive MIMO Systems Leveraging Truncated Polynomial Expansion

In this work, we propose low-complexity detectors for massive multiple-input multiple-output (MIMO) systems. Particularly, we leverage variants of truncated polynomial expansion (TPE) in order to reduce the computational complexity of the signal detection in the uplink direction. Linear detectors such as zero-forcing (ZF) and minimum mean square error (MMSE) involve expensive matrix-matrix multiplication and matrix inversion operations. TPE-based detectors are appropriate candidates for approximating these linear detectors. However, tuning the normalization factor of TPE-based detectors may require calculating the minimum and the maximum eigenvalues of the channel Gram matrix. These calculations become computationally expensive for some massive MIMO systems, especially for systems with a large ratio of single-antenna user terminals to the number of antennas at the base station, i.e., loading factor. We propose to tune the normalization factor using appropriate approximations for the extreme eigenvalues. The proposed TPE-based detectors exhibit a bit error performance similar to that of the TPE-based detector with the optimal normalization factor. Moreover, our proposed detectors achieve the error performance of ZF and MMSE for different loading factors of spatially correlated and uncorrelated massive MIMO channels. The computational complexity of the proposed detector is proportional to the number of base station antennas and the number of users.

Multi-fractional-differential operators for a thermo-elastic magnetic response in an unbounded solid with a spherical hole via the DPL model

&lt;abstract&gt; &lt;p&gt;The current research aims to investigate thermodynamic responses to thermal media based on a modified mathematical model in the field of thermoelasticity. In this context, it was considered to present a new model with a fractional time derivative that includes Caputo-Fabrizio and Atangana-Baleanu fractional differential operators within the framework of the two-phase delay model. The proposed mathematical model is employed to examine the problem of an unbounded material with a spherical hole experiencing a reduced moving heat flow on its inner surface. The problem is solved analytically within the modified space utilizing the Laplace transform as the solution mechanism. An arithmetic inversion of the Laplace transform was performed and presented visually and tabularly for the studied distributions. In the tables, specific comparisons are introduced to evaluate the influences of different fractional operators and thermal properties on the response of all the fields examined.&lt;/p&gt; &lt;/abstract&gt;

Modifikasi Algoritma Kriptografi Hill Chiper dengan Matriks Generalisasi Bilanga Fibonacci dalam Penyandian Pesan

Hill Cipher cryptographic algorithm is a technique of massage encoding by implementing a matrix of order n*n as a key matrix. The key matrix is a matrix that has a multiplicative inverse. The security of messages measured by the number of processes in encoding. More and more processes in the encoding will lead to the longer time required. So that the massage will be safer. The purpose of this research is to modify the Hill Cipher cryptographic algorithm by using the matrix of Fibonacci numbers generalization whose degree-p and rank-n Qn,p. The Matrix Qn,p is a matrix of order(p+1)*(p+1) and it will be the key matrix in the Hill Cipher cryptographic algorithm.This research showed that any matrix of Fibonacci number generalization Qn,p with p and n are positive integers that be used as a key matrix in the Hill Cipher algorithm. The modification of the Hill Cipher cryptographic algorithm has done with modifying the keys by making the degree (p) and rank (n) of Qn,p as the keys that used in the encryption and decryption process of data (message).

The Mitochondrial Genome of a Freshwater Pelagic Amphipod Macrohectopus branickii Is among the Longest in Metazoa.

There are more than 350 species of amphipods (Crustacea) in Lake Baikal, which have emerged predominantly through the course of endemic radiation. This group represents a remarkable model for studying various aspects of evolution, one of which is the evolution of mitochondrial (mt) genome architectures. We sequenced and assembled the mt genome of a pelagic Baikalian amphipod species Macrohectopus branickii. The mt genome is revealed to have an extraordinary length (42,256 bp), deviating significantly from the genomes of other amphipod species and the majority of animals. The mt genome of M. branickii has a unique gene order within amphipods, duplications of the four tRNA genes and Cox2, and a long non-coding region, that makes up about two thirds of the genome’s size. The extension of the mt genome was most likely caused by multiple duplications and inversions of regions harboring ribosomal RNA genes. In this study, we analyzed the patterns of mt genome length changes in amphipods and other animal phyla. Through a statistical analysis, we demonstrated that the variability in the mt genome length may be a characteristic of certain phyla and is primarily conferred by expansions of non-coding regions.

Tomotok: python package for tomography of tokamak plasma radiation

A python package, called Tomotok, focused on performing tomographic inversion of tokamak plasma radiation is being developed at the Institute of Plasma Physics of the Czech Academy of Sciences. It aims at providing multiple inversion algorithms with an user friendly interface. In order to enable and ease performing tomographic inversion on different devices worldwide, it is planned to publish this software as open source in the near future. In this contribution, the package structure allowing an easy implementation of various tokamak and diagnostic geometries is described and an overview of the package contents is given. Apart from inversion methods, overview of Tomotok auxiliary content is given. The package provides tools for creating simple synthetic diagnostic system. These can be used for testing and benchmarking the code. This includes tools for building geometry matrices that describe the view of detectors using single line of sight approximation and artificial data generators capable of creating simple or hollow Gaussian profiles. The implemented inversion methods cover the minimum Fisher regularisation, biorthogonal decomposition and linear algebraic methods. The implementation of each method is explained, example results obtained by inverting phantom models are presented and discussed. The computation speed of implemented algorithms is benchmarked and compared.

Quantitative R1 in the locus coeruleus in Alzheimer’s disease dementia

AbstractBackgroundPrior studies employing neuromelanin‐sensitive MRI have linked neurodegeneration in the locus coeruleus (LC) to Alzheimer’s disease (AD) pathology. MPnRAGE (Keckskemeti et al., 2016), a novel MRI technique developed at UW‐Madison, generates multiple inversion recovery contrasts and quantitative T1 relaxometry. Quantitative R1 (= 1/T1), the longitudinal relaxation rate, is sensitive to brain myelin, lipid, and iron content according to post‐mortem studies. As prior studies suggest altered quantitative R1 (QR1) among individuals with AD pathology, this imaging marker may be sensitive to AD‐associated pathology in the LC, one of the first regions in the brain to show signs of AD pathology (Braak et al., 2011). Here we performed preliminary assessments to test for differences in QR1 among individuals with and without clinical mild cognitive impairment (MCI‐AD), or AD dementia. We hypothesized that R1 would be lower among individuals with AD and MCI compared to unimpaired controls.MethodParticipants were enrolled in the Alzheimer’s Disease Connectome Project (ADCP) at UW‐Madison. 103 older adults diagnosed as cognitively unimpaired (N=53), MCI‐AD, and AD‐Dementia (Table 1) underwent MPnRAGE at a 1mm3 resolution. MPnRAGE‐derived QR1 maps were registered to MNI space using SPM12. LC masks (from Betts et al., 2017) were transformed to subject space to extract mean R1 in the bilateral LC using the Marsbar toolbox. Multiple linear regression was run within Rstudio to investigate the relationships between age, R1, and diagnosis. The main effects of interest included age and diagnosis, as well as their interaction. Sex was included as a covariate.ResultNo significant associations were found between QR1 and age, diagnostic status, and their interaction. The main effect of age on R1 trended toward significance (p=0.059). Age trends are shown in Figure 1. Sex was not a significant covariate.ConclusionWhile QR1 was not significantly associated with age or clinical diagnosis within the LC, further research will evaluate the extent to which QR1 is altered among other regions affected by AD pathology. Further, R1 could be tested between groups stratified by AD biomarker status. Finally, the LC is a small structure, thus future work could also test R1 estimated at higher resolution.

The 2019-2020 Khalili (Iran) Earthquake Sequence-Anthropogenic Seismicity in the Zagros Simply Folded Belt?

We investigate the origin of a long‐lived earthquake cluster in the Fars arc of the Zagros Simply Folded Belt that is colocated with the major Shanul natural gas field. The cluster emerged in January 2019 and initially comprised small events of M n ∼ 3–4. It culminated on 9 June 2020 with a pair of M w 5.4 and 5.7 earthquakes, which was followed by >100 aftershocks. We assess the spatiotemporal evolution of the earthquake sequence using multiple event hypocenter relocations, waveform inversions, and Sentinel‐1 Interferometric Synthetic Aperture Radar (InSAR) measurements and models. We find that the early part of the sequence is spatially distinct from the 9 June 2020 earthquakes and their aftershocks. Moment tensors, centroid depths, and source parameter uncertainties of 15 of the largest (M n ≥ 4.0) events show that the sequence is dominated by reverse faulting at shallow depths (mostly ≤4 km) within the sedimentary cover. InSAR modeling shows that the M w 5.7 mainshock occurred at depths of 2–8 km with a rupture length and maximum slip of ∼20 km and ∼0.5 m, respectively. Our results suggest that the 2019–2020 Khalili earthquake sequence was likely influenced by operation of the Shanul field, though elevated natural seismicity in the Zagros makes the association difficult to prove. Understanding how to distinguish man‐made from natural seismicity is helpful for hazard and risk assessment, notably in the Zagros, which is both seismically active and rich in oil and gas reserves.

Grade 11 Learners’ Misconceptions and Inability to Apply Basic Algebra Operations: The Case of Selected Secondary Schools in Chilanga District, Zambia

The aim of the study was to assess and establish learners’ misconception and inability to apply simplification of algebraic expressions and solving linear equations in Chilanga District. The study sought to determine the possible causes of learners’ inability to apply simplification of algebraic expressions and solving linear equations in relation to identification of inverses in senior secondary school. A case study research design was employed to achieve the objectives and a sample of 100 grade 11 learners and 10 mathematics teachers from school A and school B participated in the study. To collect data the instruments used were a questionnaire, tests and interviews. Quantitative data was analyzed using an Excel statistical package while the reliability of the instruments was tested using Cronbach’s alpha (α). The main findings the research study established are that learners misused and misapplied addition, subtraction, multiplication and division when simplifying algebraic expressions and forming linear equations. Learners also met challenges when it came to solving linear equations because they lacked knowledge of additive and multiplicative inverses. The main conclusions drawn from this research study are that misconceptions learners experience in algebra are attributed to the lack of conceptual knowledge and understanding and these misconceptions occurred frequently in learners. Keywords: Level of Education (Grade 11), Learners’ Misconception, Inability to apply basic Algebra Operation. DOI: 10.7176/JEP/12-33-11 Publication date: November 30 th 2021

Atmospheric response to the annular solar eclipse of 26 December 2019 over Cochin, India

• Atmospheric response to annular solar eclipse of December 2019. • Drastic reduction in incoming solar radiation and variations in meteorological variables. • Mean PBL and Tropopause Heights were reduced by 50% and 5.5%. • Detected the presence of internal gravity waves with periodicities of 40–60 min. • Study useful for radiative transfer calculation and also for testing numerical models. The rapid response of the atmosphere to the reduction in solar radiation during the annular solar eclipse on 26th December 2019 with maximum obscurity of 91.16% over Cochin, located in the southwest peninsular India, has been investigated. A suite of instruments encompassing an advanced VHF wind profiling Radar operating at 205 MHz, GPS radiosonde, and automatic weather station was employed to record the temporal and vertical variations in various meteorological parameters. Compared to the corresponding values averaged for two control days neighboring the eclipse day, the temperature, relative humidity, net radiation, pressure and wind speed at the surface were altered by −4.0 °C, +39.6%, −383.0 Wm −2 , +0.62 mb, and −2.6 ms −1 , respectively. The corresponding percentage variations are −13.6%, +71.0%, −67.0%, +0.06%, and −99.0% during the maximum phase of the eclipse, and approached close to the control-day values within about 2 h. Multiple temperature inversions as large as 1 °C were observed up to a height of about 7.3 km. The heights of mean planetary boundary layer (PBL) and tropopause were decreased by about 355 m (−50%) and 900 m (−5.5%), respectively during the peak of obscuration. Meanwhile, the vertical profiles of both the horizontal and vertical wind velocities demonstrate substantial reduction. The vertical wind dispersion, which characterizes the fluctuations in vertical air motion, was reduced by 34% in the PBL compared to its corresponding values on the control days. Subsequently, wavelet spectral analysis of the vertical wind yields a quasi-periodic oscillation indicating the presence of internal gravity waves with periodicities of 40–60 min in the lower altitudes up to 3 km during the eclipse day. Besides reporting the characteristic variations in various atmospheric parameters, the present study reveals the height-time variations in the vertical winds, a vital parameter of significance in the studies of convection, turbulence, and atmospheric waves.

Assessment of renal function using magnetic resonance quantitative histogram analysis based on spatial labeling with multiple inversion pulses.

BackgroundThe incidence of chronic kidney disease (CKD) is high, and is easy to develop into end-stage renal disease (ESRD), which requires kidney dialysis or kidney transplantation. Therefore, we want to explore the clinical value of magnetic resonance quantitative histogram analysis based on spatial labeling with multiple inversion pulses (SLEEK) in assessing renal function in the early stage.MethodsOne hundred and twenty-nine patients underwent abdominal MRI examination, including a coronal SLEEK sequence. The patients were divided into the control group [CG, 47 cases, estimated glomerular filtration rate (eGFR) >90], the mild renal function impairment (mRI) group (48 cases, eGFR =60–90), and the moderate to severe renal function impairment (m-sRI) group (34 cases, eGFR <60). Two experienced radiologists delineated cortex and medulla regions of interest (ROIs) on SLEEK images to obtain cortex and medulla quantitative histogram parameters [Mean, Median, Percentiles (5th, 10th, 25th, 75th, and 90th), Skewness, Kurtosis, and Entropy] using FireVoxel. These histogram parameters were compared by proper statistical methods such as one-way analysis of variance, the χ2 test, and receiver operating characteristic (ROC) curve analysis.ResultsFour histogram parameters (Inhomogeneitycortex, Skewnesscortex, Kurtosismedulla, and Entropymedulla) differed significantly between the CG and the mRI group. One medulla (Entropymedulla) and nine cortex (Meancortex, Mediancortex, Kurtosiscortex, Entropycortex, and 5th, 10th, 25th, 75th, and 90th Percentilecortex) histogram parameters were significantly different between the m-RI and m-sRI groups. The most relevant parameter to eGFR was Inhomogenitycortex (r=−0.450, P<0.001). Inhomogeneitycortex had the largest area under the curve (AUC) for differentiating the mRI group from the CG (AUC =0.718; 95% CI: 0.616–0.806), while 25th Percentilecortex generated the largest AUC (AUC =0.786; 95% CI: 0.681–0.869) for differentiating the mRI and m-sRI groups.ConclusionsQuantitative histogram parameters based on a SLEEK sequence can be used to supplement renal dysfunction assessment. Cortex histogram parameters are more valuable for evaluating renal function than medulla histogram parameters.

Polymerization-Induced Helicity Inversion Driven by Stacking Modes and Self-Assembly Pathway Differentiation.

Regulating the mutual stacking arrangements is of great interest for understanding the origin of chirality at different hierarchical levels in nature. Different from molecular level chirality, the control and manipulation of hierarchical chirality in polymer systems is limited to the use of external factors as the energetically demanding switching stimulus. Herein, the first self-assembly strategy of polymerization-induced helicity inversion (PIHI), in which the controlled packing and dynamic stereomutation of azobenzene (Azo) building blocks are realized by in situ polymerization without any external stimulus, is reported. A multiple helicity inversion and intriguing helix-helix transition of polymeric supramolecular nanofibers occurs during polymerization, which is collectively confirmed to be mediated by the transition between functionality-oriented π-π stacking, H-, and J-aggregation. The studies further reveal that helicity inversion proceeds through a delicate interplay of the thermodynamically and kinetically controlled, pathway-dependent interconversion process, which should provide new insight into the origin and handedness control of helical nanostructures with desired chirality.