Resource
2023 EN
Navid Anjum Aadit · Srijan Nikhar · Sidharth Kannan
+2 more
Domain-specific hardware to solve computationally hard optimization problemshas generated tremendous excitement recently. Here, we evaluate probabilisticbit (p-bit) based Ising Machines (IM), or p-computers with a benchmarkcombinatorial optimization problem, namely the 3-regular 3-XOR Satisfiability(3R3X). The 3R3X problem has a glassy energy landscape and it has recently beenused to benchmark various IMs and other solvers. We introduce a multiplexedarchitecture where p-computers emulate all-to-all (complete) graphfunctionality despite being interconnected in highly sparse networks, enablinghighly parallelized Gibbs sampling. We implement this architecture in FPGAs andshow that p-bit networks running an adaptive version of the powerful paralleltempering algorithm demonstrate competitive algorithmic and prefactoradvantages over alternative IMs by D-Wave, Toshiba and others. Scaled magneticnanodevice-based realizations of p-computers could lead to orders-of-magnitudefurther improvement according to experimentally established projections.
Resource
2023 EN
M. Mirac Serim · Danjela Serim · Çağatay Kerem Dönmez
+4 more
We report on the timing characteristics of MXB 0656-072 throughout its2007-2008 type I outbursts utilising RXTE/PCA and Fermi/GBM data. Using pulsetiming technique, we explore the spin frequency evolution of the source duringthis interval. Subsequently, by examining the torque-luminosity relation, weshow that the overall frequency evolution is substantially in line with theGhosh-Lamb model. Furthermore, the residuals of the spin frequencies do notexhibit clear orbital modulations, which possibly indicate that the system isobserved on a relatively top view. In the RXTE/PCA observations, the pulsedemission is found to be disappearing below $\sim$$5 \times 10^{36}$ ergs$^{-1}$, whereas the profiles maintain stability above this value within ouranalysis timeframe. In addition, we incorporate two novel methods along withthe conventional Deeter method in order to generate higher-resolution powerdensity spectra (PDS). A red noise pattern in the PDSs is also verified inthese new methods, common in disk-fed sources, with a steepness of $\Gamma \sim-2$, reaching saturation at a time-scale of $\sim$150 d. Considering the modelsfor spectral transitions, we discuss the possible scenarios for the dipolarmagnetic field strength of MXB 0656-072 and its coherence with deductions fromthe cyclotron resonance scattering feature (CRSF).
Resource
2023 EN
Lucas Heger · Kerem Akdogan · Matthias Schott
During the COVID-19 pandemic, a large variance of incidence rates on locallevel, e.g. cities and districts, within one country has been observed, whilethe same non-pharmaceutical measures have been taken to control the spread ofthe virus. This variance in incidence rates triggered the question, if thespread of incidence rates can be explained only by statistical processes andthe local population statistics or if indeed other factors, e.g. localinformation campaigns, have to be considered. Within this paper we study theexpected spread of incidence rates in the German State of Rhineland Palatinateduring the second COVID-19 wave using an agent based simulation and find thatthe spread of incidence rates can be solely explained by population statisticsand further statical effects.
Resource
2023 EN
Lucas Heger · Kerem Akdogan · Matthias Schott
The effect of school closures on the spread of COVID-19 has been discussedamong experts and the general public since those measures have been taken onlya few months after the start of the pandemic in 2020. Within this study, theJuneGermany framework, is used to quantify the impact of school closures in theGerman state Rhineland Palatinate using an agent-based simulation approach. Itwas found that the simulations predicts a reduction of the number ofinfections, hospitalizations as well as death by a factor of 2.5 compared toscenarios, where no school closures are enforced, during the second wavebetween October 2020 and February 2021
Journals
2022 EN
Gafni Tal · Gabriel Kelley Pettee · Shuval Kerem
+3 more
Background Physical activity (PA), and particularly moderate to vigorous intensity PA (MVPA), may protect against cognitive decline. However, the underlying mechanisms are not fully understood. Cardiac autonomic balance is influenced by PA and implicated in dementia pathogenesis. Therefore, the study aimed to examine whether autonomic balance mediates the association between PA and cognitive function. Method The sample included 1,939 participants from the Coronary Artery Risk Development in Young Adults (CARDIA) study. MVPA was obtained in 7 consecutive examinations from baseline (1985‐86; 18‐30 years) to the Year 20 exam. Cardiac autonomic balance was assessed at Year 20 via resting heart rate, and via measures of heart rate variability: standard deviation normal to normal (SDNN) and root mean square of successive differences (RMSDD). A comprehensive cognitive assessment was performed at Year 30. Group‐based trajectory modeling was used to identify homogenous MVPA trajectory groups, and formal mediation analysis was used to test whether cardiac autonomic function indices lie on the causal pathway between MVPA trajectories and cognitive function. Result Three distinct PA trajectory patterns were identified: (1) Below MVPA guidelines (n = 1,122; 57.9%); (2) Meeting MVPA guidelines (n = 652; 33.6%); and (3) Exceeding MVPA guidelines (n = 165; 8.5%) (Figure). Meeting and exceeding MVPA guidelines were related to lower resting heart rate and higher heart rate variability, which indicate improved autonomic balance. Meeting and exceeding MVPA guidelines were additionally associated with improved semantic fluency performance. The association between higher MVPA level and semantic fluency performance was fully mediated by RMSDD and partially mediated by SDNN. No additional associations were observed between MVPA trajectories and other cognitive outcomes, and no statistically significant mediation by autonomic balance indices was found for these associations (Table). Conclusion Higher MVPA levels across the young adult to midlife transition were associated with better cardiac autonomic function, which in turn explained some of the associations between PA trajectories and better semantic fluency performance. Future studies, particularly among older individuals are warranted to clarify the role of autonomic balance in the link between physical activity and brain health. These findings may lead to more targeted PA recommendations across the life‐course to slow cognitive decline and decrease dementia risk.
Journals
2022 EN
Gafni Tal · Weinstein Galit · David Leonard
+5 more
Background Cardiorespiratory fitness (CRF) and body mass index (BMI) are each independently related to premature mortality. Previous research indicates that high fitness is protective against premature mortality even among those who are overweight or obese. We aimed to explore the independent and joint associations of CRF and BMI with incident dementia among middle‐aged adults. Method Data on CRF, BMI and covariates were derived from the Cooper Center Longitudinal Study (CCLS). The sample included 6,458 middle‐aged adults (mean age 50.9±7.6 years; 85% men; mean CRF 11.6±2.3 METs and BMI 25.3±3.2 kg/m 2 ), who attended the Cooper Clinic (Dallas, TX) for preventive medical exams twice between 1970‐1999 (mean time between exams 2.5±2.1 years), and had fee‐for‐service Medicare coverage after age 65 at any time between 1999 and 2009. Maximal metabolic equivalents (MET) levels of CRF were computed based on the final speed and grade on treadmills. BMI was calculated based on measurements of weight and height (kg/m 2 ). The primary independent variables consisted of average CRF and BMI from the two exams and the change between exams. The chronic condition warehouse definition of Alzheimer’s disease and related dementias was based on the International Classification of Diseases, 9 th Revision. Proportional hazards models were applied to investigate the independent and joint associations of midlife CRF and BMI and their change over time with dementia diagnosis adjusted for age, sex, education, systolic blood pressure and fasting glucose and cholesterol levels. Result Over 40,975 person‐years of Medicare surveillance (average 6.3±3.6), 637 cases of dementia were identified. Average CRF and BMI were each related to incident dementia (HR = 0.95 per MET 95% CI 0.91‐0.99 and HR = 1.03 per kg/m 2 95% CI 1.00‐1.06, respectively), but not the interaction. Change in CRF or BMI between exams did not predict incident dementia. Conclusion In line with studies exploring the link of CRF and BMI with mortality, our findings suggest that baseline fitness is related to dementia incidence independently of body mass and that significant joint effects were not observed.
Journals
2022 EN
Kocaarslan Azra · Kaya Kerem · Jockusch Steffen
+1 more
The synthesis of step‐growth polymers by photoinduced methods is a challenging issue in synthetic chemistry. Here, we report a single component near UV responsive photopolymerization system for step‐growth polymerization of N ‐methylpyrrole (MPyr) and N ‐methylindole (MIn) by using phenacyl bromide (PAB). The obtained high molecular weight conjugated polymers were characterized by spectral and chromatographic methods. Detailed laser flash photolysis and spectroscopic studies revealed that polymerization proceeds by successive photoinduced cleavage of PAB followed by electron transfer, proton release and coupling processes. After photolysis, chain growth continues also in daylight or dark by acidic oxidation. The structural features of the polymers were investigated. PAB single component photoinitiator enables an efficient, rapid, room temperature step‐growth polymerization process of MPyr and MIn that can be applied to other conjugated monomers.
Journals
2022 EN
Kocaarslan Azra · Kaya Kerem · Jockusch Steffen
+1 more
The synthesis of step‐growth polymers by photoinduced methods is a challenging issue in synthetic chemistry. Here, we report a single component near UV responsive photopolymerization system for step‐growth polymerization of N ‐methylpyrrole (MPyr) and N ‐methylindole (MIn) by using phenacyl bromide (PAB). The obtained high molecular weight conjugated polymers were characterized by spectral and chromatographic methods. Detailed laser flash photolysis and spectroscopic studies revealed that polymerization proceeds by successive photoinduced cleavage of PAB followed by electron transfer, proton release and coupling processes. After photolysis, chain growth continues also in daylight or dark by acidic oxidation. The structural features of the polymers were investigated. PAB single component photoinitiator enables an efficient, rapid, room temperature step‐growth polymerization process of MPyr and MIn that can be applied to other conjugated monomers.
Journals
2022 EN
Reuven Or · Mikula Ivan · AshkenaziPreiser Hadas
+7 more
Abstract Myeloid‐derived suppressor cells (MDSCs) are heterogenous populations of immature myeloid cells that can be divided into two main subpopulations, polymorphonuclear (PMN) MDSCs and monocytic (M) MDSCs. These cells accumulate during chronic inflammation, characterizing an array of pathologies such as cancer, inflammatory bowel disease, and infectious and autoimmune diseases, and induce immunosuppression. The suppressive effects of MDSCs on the immune system are studied mainly when focusing on their features, functions, and impact on target cells such as T cells, natural killer cells, and B cells, among others. Herein, we describe methods for the analysis of MDSC immunosuppressive features and functions, measuring different mediators that contribute to their activities and how they impact on T cell function. The protocols described are a continuation to those in a companion Current Protocols article by Reuven et al. (2022), which uses a generated single‐cell suspension and isolated cells to test their activity. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. This article was corrected on 13 December 2024. See the end of the full text for details. Basic Protocol 1 : Evaluating MDSC suppressive features Alternate Protocol 1 : Dichlorofluorescein diacetate–based reactive oxygen species detection Support Protocol 1 : Detection of nitric oxide secretion Support Protocol 2 : Measurement of arginase activity Basic Protocol 2 : Evaluating MDSC suppressive function Alternate Protocol 2 : In vitro effects of MDSCs on expression of T cell receptor complex during activation Support Protocol 3 : Effect of MDSCs on interferon γ production Basic Protocol 3 : Effect of MDSCs on T cell proliferation Basic Protocol 4 : Effect of MDSCs on T cell cytotoxic activity Alternate Protocol 3 : In vivo cytotoxicity assay Basic Protocol 5 : Analysis of MDSC differentiation
Journals
2022 EN
BenMeir Kerem · Twaik Nira · Meirow Yaron
+1 more
Abstract Myeloid‐derived suppressor cells (MDSCs) represent a heterogeneous population of immature myeloid cells known to play a role in perpetuating a wide range of pathologies, such as chronic infections, autoimmune diseases, and cancer. MDSCs were first identified in mice by the markers CD11b + Gr1 + , and later, based on their morphology, they were classified into two subsets: polymorphonuclear MDSCs, identified by the markers CD11b + Ly6G + Ly6C Low , and monocytic MDSCs, detected as being CD11b + Ly6G – Ly6C Hi . MDSCs are studied as immunosuppressive cells in various diseases characterized by chronic inflammation and are associated with disease causes/triggers such as pathogens, autoantigens, and cancer. Therefore, different diseases may diversely affect MDSC metabolism, migration, and differentiation, thus influencing the generated MDSC functional features and ensuing suppressive environment. In order to study MDSCs in a pathology‐free environment, we established and calibrated a highly reproducible mouse model that results in the development of chronic inflammation, which is the major cause of MDSC accumulation and immune suppression. The model presented can be used to study MDSC phenotypes, functional diversity, and plasticity. It also permits study of MDSC migration from the bone marrow to peripheral lymphatic and non‐lymphatic organs and MDSC crosstalk with extrinsic factors, both in vivo and ex vivo . Furthermore, this model can serve as a platform to assess the effects of anti‐MDSC modalities. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol : Repetitive M.tb immunizations for the induction of chronic inflammation Alternate Protocol 1 : Creating a lower grade of inflammation by changing the site of immunization Alternate Protocol 2 : In vivo evaluation of immune status Support Protocol 1 : Preparation of reconstituted M.tb aliquots and M.tb‐IFA emulsions for each of the three injections Support Protocol 2 : Preparation of an ovalbumin lentiviral expression vector Support Protocol 3 : Fluorescence titering assay for the lentiviral expression vector Support Protocol 4 : Spleen excision, tissue dissociation, and preparation of a single‐cell suspension Support Protocol 5 : Labeling of splenocytes with CFSE proliferation dye