Special Subset Research Articles

Magnetar spin-down glitch clearing the way for FRB-like bursts and a pulsed radio episode

Magnetars are a special subset of the isolated neutron star family, with X-ray and radio emission mainly powered by the decay of their immense magnetic fields. Many attributes of magnetars remain poorly understood: spin-down glitches or the sudden reductions in the star’s angular momentum, radio bursts reminiscent of extragalactic fast radio bursts (FRBs) and transient pulsed radio emission lasting months to years. Here we unveil the detection of a large spin-down glitch event (fractional change in spin frequency $$| {{\Delta }}\nu /\nu | =5.{8}_{-1.6}^{+2.6}\times 1{0}^{-6}$$ ) from the magnetar SGR 1935+2154 on 5 October 2020 (±1 day). We find no change to the source-persistent surface thermal or magnetospheric X-ray behaviour, nor is there evidence of strong X-ray bursting activity. Yet, in the subsequent days, the magnetar emitted three FRB-like radio bursts followed by a month-long episode of pulsed radio emission. Given the rarity of spin-down glitches and radio signals from magnetars, their approximate synchronicity suggests an association, providing pivotal clues to their origin and triggering mechanisms with ramifications to the broader magnetar and FRB populations. We postulate that impulsive crustal plasma shedding close to the magnetic pole generates a wind that combs out magnetic field lines, rapidly reducing the star’s angular momentum while temporarily altering the magnetospheric field geometry to permit the pair creation needed to precipitate radio emission. An abrupt slow-down in a magnetar’s rotation rate (a ‘glitch’) may be related to the subsequent emission of three radio bursts (resembling fast radio bursts) and a month-long episode of pulsed radio emission.

CD161 Characterizes an Inflamed Subset of Cytotoxic T Lymphocytes Associated with Prolonged Survival in Human Papillomavirus-Driven Oropharyngeal Cancer.

Human papillomavirus (HPV)-driven oropharyngeal carcinoma (OPSCC) is distinct from tobacco- or alcohol-associated OPSCC and has a unique immune landscape. Studies have supported the heterogeneity of T cells, accompanied by a broad repertoire of T-cell responses, within tumors driven by HPV infection. However, the phenotype and function of these HPV-related T cells remain unclear. Using a combination of single-cell RNA sequencing, flow cytometry, pharmacologic inhibition, and immunofluorescence staining, we explored the prognostic implication of HPV-related T cells and further validated our findings in two independent cohorts. Cytotoxic T lymphocytes (CTL) within OPSCC displayed a spectrum of transcriptional signatures. Among which, we identified CD161 receptor, encoded by KLRB1, as a potential marker to distinguish the CTL subsets in HPV-positive OPSCC with a divergent evolutionary trajectory. In-depth analysis revealed that CD161+ CTLs exhibited a more robust immune response over the CD161- counterparts and a T cell-inflamed phenotype that could be further reinvigorated by immune-checkpoint blockade. Despite the high expression of exhaustion markers, reinforcement of CD161+ CTL reactivity was expected to boost immune responses, considering their functional reversibility. We further confirmed that the high level of intratumoral CD161+ CTLs associated with a favorable treatment response and prolonged overall survival. Therefore, our research not only provides an insight into the immune landscape of HPV-driven OPSCC but also sheds light on a special subset of CTLs with prognostic and therapeutic significance.

Time correlation of success recanalization for endovascular recanalization of medically refractory non-acute intracranial arterial occlusions.

The management of patients with symptomatic non-acute atherosclerotic intracranial artery occlusion (sNAA-ICAO), which is a special subset with high morbidity and a high probability of recurrent serious ischemic events despite standard medical therapy, has been clinically challenging. A number of small-sample clinical studies have discussed endovascular recanalization for sNAA-ICAO and the lack of a uniform standard of operation time. The purpose of this study was to investigate the time correlation of successful recanalization. From January 2013 to August 2021, 69 consecutive patients who underwent endovascular recanalization for sNAA-ICAO were analyzed retrospectively in the First Affiliated Hospital of Harbin Medical University. The technical success rate, periprocedural complications, and rate of TIA/ischemic stroke during follow-up were evaluated. The overall technical success rate was 73.91% (51/69), and the rate of perioperative complications was 37.68% (26/69). The percentage of patients with perioperative symptoms was 27.53% (19/69). The rate of serious symptomatic perioperative complications was 8.70% (6/69). After adjusting for age, sex, and BMI, the effect of the time from the last symptom to operation on successful recanalization was 0.42 (IQR, 0.20, 0.88, P = 0.021), before the inflection point (51 days). Endovascular recanalization for sNAA-ICAO is technically feasible in reasonably selected patients. The perioperative safety is within the acceptable range. Before 51 days, the last symptoms to operation time, for every 10 days of delay, the probability of successful recanalization is reduced by 57%.

Time-optimal feedback control for the game of two Isotropic Rockets

In this paper, the problem of computing feedback solutions for time-optimal pursuit-evasion between two Isotropic Rockets is considered. The classical version of the game involves an Isotropic Rocket chasing a simple velocity bounded kinematic evader. Here a modified and more general version, with both players as Isotropic Rockets, is investigated using the recently developed technique of containment of continuous subsets of reachable sets. Under a suitable assumption on the initial conditions, a complete characterisation of capture is first provided using these special subsets. The geometry of these sets is then used to compute the feedback policy, through the solution of a quartic equation at each instant of time. Fortunately, quartic equations can be solved analytically or numerically in an efficient manner. Thus the feedback law can be implemented in real time. Simulation results are given to show the agreement of the proposed laws with the numerical results obtained using an available algorithm for computing open loop representations of min-max policies.

Hardness of Braided Quantum Circuit Optimization in the Surface Code

Large-scale quantum information processing requires the use of quantum error correcting codes to mitigate the effects of noise in quantum devices. Topological error-correcting codes, such as surface codes, are promising candidates as they can be implemented using only local interactions in a two-dimensional array of physical qubits. Procedures such as defect braiding and lattice surgery can then be used to realize a fault-tolerant universal set of gates on the logical space of such topological codes. However, error correction also introduces a significant overhead in computation time, the number of physical qubits, and the number of physical gates. While optimizing fault-tolerant circuits to minimize this overhead is critical, the computational complexity of such optimization problems remains unknown. This ambiguity leaves room for doubt surrounding the most effective methods for compiling fault-tolerant circuits for a large-scale quantum computer. In this paper, we show that the optimization of a special subset of braided quantum circuits is NP-hard by a polynomial-time reduction of the optimization problem into a specific problem called Planar Rectilinear 3SAT.

Solving airline crew pairing problems through constraint partitioning

In this paper, a decomposition technique based on constraint partitioning is developed to solve the crew pairing problem (CPP) which has an overriding importance in the airline industry as it determines the crew cost. The method is based on the observation that in large-scale problems, the constraints can be partitioned to some sub-problems which involve special subsets of variables. The resultant structure is called the 'partitioned structure'. Therefore, in the proposed method, first, a feasible solution is generated for a reduced CPP with a 'partitioned structure' through the optimal solutions of its sub-problems. Then, at each step, the feasible solution is improved through adding/removing some pairings to/from it. The proposed algorithm is applied to a case study from the literature as well as some randomly generated test problems. One advantage of the proposed method is finding multiple feasible solutions with lower time than the method used to solve the case. [Submitted: 8 May 2020; Accepted: 29 December 2021]

Divergent Contribution of the Golgi Apparatus to Microtubule Organization in Related Cell Lines.

Membrane trafficking in interphase animal cells is accomplished mostly along the microtubules. Microtubules are often organized radially by the microtubule-organizing center to coordinate intracellular transport. Along with the centrosome, the Golgi often serves as a microtubule-organizing center, capable of nucleating and retaining microtubules. Recent studies revealed the role of a special subset of Golgi-derived microtubules, which facilitates vesicular traffic from this central transport hub of the cell. However, proteins essential for microtubule organization onto the Golgi might be differentially expressed in different cell lines, while many potential participants remain undiscovered. In the current work, we analyzed the involvement of the Golgi complex in microtubule organization in related cell lines. We studied two cell lines, both originating from green monkey renal epithelium, and found that they relied either on the centrosome or on the Golgi as a main microtubule-organizing center. We demonstrated that the difference in their Golgi microtubule-organizing activity was not associated with the well-studied proteins, such as CAMSAP3, CLASP2, GCC185, and GMAP210, but revealed several potential candidates involved in this process.

Guns, Guerrillas, and the Great Leader: North Korea and the Third World by Benjamin R. Young

<i>Guns, Guerrillas, and the Great Leader: North Korea and the Third World</i> by Benjamin R. Young

ANALYSIS OF MARСOVIAN SYSTEMS WITH A GIVEN SET OF SELECTED STATES

Analysis of stationary Marcovian systems is traditionally performed using systems of linear Kolmogorov differential equations. Such systems make it possible to determine the probability of the analyzed system being in each of its possible states at an arbitrary time. This standard task becomes more complicated if the set of possible states of systems is heterogeneous and some special subset can be distinguished from it, in accordance with the specifics of the system functioning. Subject of the study is technology development for such systems analysis. In accordance with this, the purpose of the work is to find the distribution law of the random duration of such a system's stay on a set of possible states until it falls into a selected subset of these states. Method for solving the problem is proposed based on splitting the entire set of possible states of the system into two subsets. The first of them contains a selected subset of states, and the second contains all the other states of the system. Now a subset of states is allocated from the second subset, from which a direct transition to the states of the first subset is possible. Next, a system of differential equations describing the transitions between the formed subsets is formed. The solution of this system of equations gives the desired result – distribution of the random duration of the system's stay until the moment of the first hit in the selected subset of states. The method allows solving a large number of practical problems, for example, in the theory of complex systems reliability with many different failure states. In particular, finding the law of the uptime duration distribution, calculating the average duration of uptime.

Development and validation of nomogram prognostic model for early-stage T1-2N0M0 small cell lung cancer: A population-based analysis.

Survival outcomes of early-stage T1-2N0M0 small cell lung cancer (SCLC) patients differ widely, and the existing Veterans Administration Lung Study Group (VALSG) or TNM staging system is inefficient at predicting individual prognoses. In our study, we developed and validated nomograms for individually predicting overall survival (OS) and lung cancer-specific survival (LCSS) in this special subset of patients. Data on patients diagnosed with T1-2N0M0 SCLC between 2000 and 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. All enrolled patients were split into a training cohort and a validation cohort according to the year of diagnosis. Using multivariable Cox regression, significant prognostic factors were identified and integrated to develop nomograms for 1-, 3-, and 5-year OS and LCSS prediction. The prognostic performance of our new model was measured by the concordance index (C-index) and calibration curve. We compared our latest model and the 8th AJCC staging system using decision curve analyses (DCA). Kaplan-Meier survival analyses were applied to test the application of the risk stratification system. A total of 1,147 patients diagnosed from 2000 to 2011 were assigned to the training cohort, and 498 cases that were diagnosed from 2012 to 2015 comprised the validation cohort. Age, surgery, lymph node removal (LNR), and chemotherapy were independent predictors of LCSS. The variables of sex, age, surgery, LNR, and chemotherapy were identified as independent predictors of OS. The above-mentioned prognostic factors were entered into the nomogram construction of OS and LCSS. The C-index of this model in the training cohort was 0.663, 0.702, 0.733, and 0.658, 0.702, 0.733 for predicting 1-, 3-, and 5-year OS and LCSS, respectively. Additionally, in the validation cohort, there were 0.706, 0.707, 0.718 and 0.712, 0.691, 0.692. The calibration curve showed accepted prediction accuracy between nomogram-predicted survival and actual observed survival, regardless of OS or LCSS. In addition, there were significant distinctions in the survival curves of OS and LCSS between different risk groups stratified by prognostic scores. Compared with the 8th AJCC staging system, our new model also improved net benefits. We developed and validated novel nomograms for individual prediction of OS and LCSS, integrating the characteristics of patients and tumors. The model showed superior reliability and may help clinicians make treatment strategies and survival predictions for early-stage T1-2N0M0 SCLC patients.

Utility of Gadolinium Use in the Imaging Follow-Up of Nonenhancing Primary Brain Neoplasms in Children.

Background and purpose Gadolinium-based contrast agents (GBCAs) have been administered clinically since 1988. They are remarkably well tolerated by children and result in dose-dependent tissue deposition, even in patients with normal renal function. No adverse effects of gadolinium deposition in patients with normal renal function have been established. Given the uncertain effects of gadolinium deposition, we sought to analyze gadolinium use in the imaging follow-up of nonenhancing primary brain neoplasms in children. Materials and methods This retrospective, institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study evaluated pediatric patients who received GBCA in the routine evaluation of brain neoplasms. This special subset included 30 patients (<18 years old) with initially nonenhancing primary intracranial neoplasms who received treatment and follow-up at our institution. Patient data included sex, age from diagnosis to most recent imaging follow-up, number of contrast-enhanced magnetic resonance imaging (MRI) follow-up exams, and histopathology from a biopsy or resection. Results The group had an expected variety of tumors, including low-grade astrocytomas, dysembryoplastic neuroepithelial tumors, oligodendrogliomas, and teratomas. Half of our patients had tumors of unknown histopathology that were not biopsied or resected. The median age at diagnosis was 8.9 years, the median of four follow-up MRIs per patient, and the median follow-up time of four years. Only one of the 30 patients developed an enhancing focus on follow-up MRI that remained stable and asymptomatic over two years and did not require surgical intervention. Conclusion Judicious use of GBCA in children, especially when numerous exams over many years are anticipated, is advised given the data regarding soft-tissue deposition. Preliminary results suggest that it may be feasible to omit GBCA from routine follow-ups of initially nonenhancing brain neoplasms.

Therapy of PsO in Special Subsets of Patients.

Psoriasis is a chronic, inflammatory skin disease that may occur at any age, with a bimodal peak of incidence around the age of 16-20 years of age (early onset) and 57-60 years (late-onset). It is estimated that roughly 70% of patients develop the disease before the age of 40, which coincides with the reproductive years. Moreover, psoriasis is a chronic disease, meaning that, with increased life-duration expectancy, the number of patients affected with psoriasis aged over 65 years is going to increase and represent a big therapeutic challenge. Actually, no specific drug recommendation is available, based only on the age of the patients, while therapeutic prescription should take into account that elderly patients have more comorbidities than younger patients, with polypharmacy and an increased risk of drug interactions. Women with psoriasis are more likely to report a worse influence of the disease on their quality of life, and they are more susceptible to the development of depression. Furthermore, pregnancy and lactation represent a major contraindication to several systemic agents, and only a few studies exist providing the safety of certain drugs during these periods of life of a woman, such as certolizumab pegol. In this paper, we discuss systemic therapeutic strategies, including conventional and biological therapies, in a special subset of patients affected with moderate-to-severe psoriasis focusing on elderly patients and on female patients in fertile age, pregnancy, and lactation.

Innate Immune Cells during Machine Perfusion of Liver Grafts-The Janus Face of Hepatic Macrophages.

Machine perfusion is an emerging technology in the field of liver transplantation. While machine perfusion has now been implemented in clinical routine throughout transplant centers around the world, a debate has arisen regarding its concurrent effect on the complex hepatic immune system during perfusion. Currently, our understanding of the perfusion-elicited processes involving innate immune cells remains incomplete. Hepatic macrophages (Kupffer cells) represent a special subset of hepatic immune cells with a dual pro-inflammatory, as well as a pro-resolving and anti-inflammatory, role in the sequence of ischemia-reperfusion injury. The purpose of this review is to provide an overview of the current data regarding the immunomodulatory role of machine perfusion and to emphasize the importance of macrophages for hepatic ischemia-reperfusion injury.

BAR-CODES OF SIERPIŃSKI RELATIVES WITH TRIANGLE CONVEX HULLS

This paper presents results about the triangle Sierpiński relatives. These are Sierpiński relatives that have the same convex hull (whose boundary is a right isosceles triangle) as the Sierpiński gasket. In general, the Sierpiński relatives all have the same fractal dimension but different topologies. The special subset of triangle relatives includes are all both path-connected and multiply-connected. We investigate the epsilon hulls of the relatives (sets of all points within a distance of [Formula: see text] to the relative) to characterize and compare. This analysis includes the topological bar-codes which convey information about the connectivity of the [Formula: see text]-hulls of the relatives as [Formula: see text] ranges over the non-negative reals. We also prove that the growth rate of holes in the [Formula: see text]-hulls is equal to the fractal dimension.

External direct products on dual UP (BCC)-algebras

The concept of the direct product of finite family of \(\textit{B}\)-algebras is introduced by Lingcong and Endam [J. A. V. Lingcong, J. C. Endam, Int. J. Algebra, \(\textbf{10}\) (2016), 33--40]. In this paper, we introduce the concept of the direct product of infinite family of BCC-algebras and prove that it is a dual BCC-algebras (dBCC-algebras), we call the external direct product dBCC-algebra induced by BCC-algebras, which is a general concept of the direct product in the sense of Lingcong and Endam. We find the result of the external direct product of special subsets of BCC-algebras. Also, we introduce the concept of the weak direct product dBCC-algebras. Finally, we provide several fundamental theorems of (anti-)BCC-homomorphisms in view of the external direct product dBCC-algebras.

External and weak direct products of UP (BCC)-algebras

The concept of the direct product of finite family of \textit{B}-algebras is introduced by Lingcong and Endam [{J. A. V. Lingcong, J. C. Endam, Int. J. Algebra, \textbf{10} (2016), 33--40}]. In this paper, we introduce the concept of the direct product of infinite family of UP (BCC)-algebras, we call the external direct product, which is a general concept of the direct product in the sense of Lingcong and Endam, and find the result of the external direct product of special subsets of UP (BCC)-algebras. Also, we introduce the concept of the weak direct product of UP (BCC)-algebras. Finally, we provide several fundamental theorems of (anti-)UP (BCC)-homomorphisms in view of the external direct product UP (BCC)-algebras.

Role of Perineuronal nets in the cerebellar cortex in cocaine-induced conditioned preference, extinction, and reinstatement

Perineuronal nets (PNNs) are cartilage-like structures of extracellular matrix molecules that enwrap in a net-like manner the cell-body and proximal dendrites of special subsets of neurons. PNNs stabilize their incoming connections and restrict plasticity. Consequently, they have been proposed as a candidate mechanism for drug-induced learning and memory. In the cerebellum, PNNs surround Golgi inhibitory interneurons and both inhibitory and excitatory neurons in the deep cerebellar nuclei (DCN). Previous studies from the lab showed that cocaine-induced conditioned memory increased PNN expression in the granule cell layer of the posterior vermis. The present research aimed to investigate the role of cerebellar PNNs in cocaine-induced conditioned preference. For this purpose, we use the enzyme chondroitinase ABC (ChABC) to digest PNNs at different time points of the learning process to ascertain whether their removal can affect drug-induced memory. Our results show that PNN digestion using ChABC in the posterior vermis (Lobule VIII) did not affect the acquisition of cocaine-induced conditioned preference. However, the removal of PNNs in Lobule VIII -but not in the DCN- disrupted short-term memory of conditioned preference. Moreover, although PNN digestion facilitated the formation of extinction, reinstatement of cocaine-induced conditioned preference was encouraged under PNN digestion. The present findings suggests that PNNs around Golgi interneurons are needed to maintain cocaine-induced Pavlovian memory but also to stabilize extinction memory. Conversely, PNN degradation within the DCN did not affect stability of cocaine-induced memories. Therefore, degradation of PNNs in the vermis might be used as a promising tool to manipulate drug-induced memory.

Special Subsets of Addresses for Blockchains Using the secp256k1 Curve

In 2020, Sala, Sogiorno and Taufer were able to find the private keys of some Bitcoin addresses, thus being able to spend the cryptocurrency linked to them. This was unexpected since the recovery of non-trivial private keys for blockchain addresses is deemed to be an infeasible problem. In this paper, we widen this analysis by mounting a similar attack on other small subsets of the set of private keys. We then apply it to other blockchains as well, examining Ethereum, Dogecoin, Litecoin, Dash, Zcash and Bitcoin Cash. In addition to the results, we also explain the techniques we have used to perform this exhaustive search for all the addresses that have ever appeared in these blockchains, and we give an estimate of the time needed to perform all the computations. Finally, we also examine the possibility of mounting a similar attack on other elliptic curves used in blockchains, i.e., Curve25519 and NIST P-256.

Modulation Instability and Non-Degenerate Akhmediev Breathers of Manakov Equations

We reveal a special subset of non-degenerate Akhmediev breather (AB) solutions of Manakov equations that only exist in the focusing case. Based on exact solutions, we present the existence diagram of such excitations on the frequency-wavenumber plane. Conventional single-frequency modulation instability leads to simultaneous excitation of three ABs with two of them being non-degenerate.

Multi-Phenotypic Exosome Secretion Profiling Microfluidic Platform for Exploring Single-Cell Heterogeneity.

Cellular phenotypic and functional heterogeneities have advanced cancer evolution and treatment resistance. Although exosome-bound proteins reflect cellular functions, single-cell exosomes are rarely profiled owing to the lack of effective platforms. Herein, the authors developed an integrated microfluidic platform consisting of a single-cell trapping chip and a spatially coded antibody barcode chip for the multiplexed outline of exosome secretion by single cells. Using this platform, five phenotypic exosomes of over 1000 single cells are simultaneously profiled, in addition to inflammatory factor secretion from the same single cell. Also, a robust analysis workflow for single-cell secretion profiling is proposed to explore the intercellular heterogeneity, which integrated unsupervised clustering and linear clustering. When applied to the tumor cell lines of epithelial-origin and normal epithelial cell lines, the strategy identifies functionally heterogeneous subpopulations with unique secretion patterns. Notably, special functional cell subsets for unique phenotypic exosomes (HSP70+ , EPCAM+ ) are found within ovarian tumor cells. The strategy proposed offers a new analysis approach for cellular differential exosome secretion at single-cell resolution using inflammatory factors, ultimately reinforcing the understanding of cell-to-cell heterogeneity and tumor landscape, and providing a valuable universal platform for single-cell biomarker exploration in biological and clinical research.