Theoretical model of the dynamic spin polarization of nuclei coupled to paramagnetic point defects in diamond and silicon carbide

Dynamic nuclear spin polarization (DNP) mediated by paramagnetic point defects in semiconductors is a key resource for both initializing nuclear quantum memories and producing nuclear hyperpolarization. DNP is therefore an important process in the field of quantum-information processing, sensitivity-enhanced nuclear magnetic resonance, and nuclear-spin-based spintronics. DNP based on optical pumping of point defects has been demonstrated by using the electron spin of nitrogen-vacancy (NV) center in diamond, and more recently, by using divacancy and related defect spins in hexagonal silicon carbide (SiC). Here, we describe a general model for these optical DNP processes that allows the effects of many microscopic processes to be integrated. Applying this theory, we gain a deeper insight into dynamic nuclear spin polarization and the physics of diamond and SiC defects. Our results are in good agreement with experimental observations and provide a detailed and unified understanding. In particular, our findings show that the defects' electron spin coherence times and excited state lifetimes are crucial factors in the entire DNP process

Kinerja Pengawas SMA/SMK Ditinjau dari Lingkungan Kerja dan Motivasi Kerja di Wilayah Kaili

Tujuan penelitian ini adalah untuk mengetahui besar hubungan kinerja pengawas SMA/SMK di tinjau dari lingkungan kerja dan motivasi kerja pengawas sekolah di Wilayah Kaili. (1) Lingkungan kerja dengan kinerja pengawas SMA/SMK di Wilayah Kaili, (2) Motivasi kerja dengan kinerja pengawas SMA/SMK di Wilayah Kaili, (3) Lingkungan kerja dan motivasi kerja dengan Kinerja pengawas SMA/SMK di Wilayah Kaili, (4) Lingkungan kerja dengan kinerja pengawas SMA/SMK di Wilayah Kaili apabila motivasi kerja dikontrol, (5) Motivasi kerja dengan kinerja pengawas SMA/SMK di Wilayah Kaili apabila lingkungan kerja pengawas dikontrol. Penelitian ini adalah penelitian survey yang bersifat korelasional. Populasi dalam penelitian ini adalah seluruh pengawas SMA / SMK di Wilayah Kaili yaitu Kota Palu, Kabupaten Donggala, Kabupaten Parigi, dan Kabupaten Sigi dengan jumlah pengawas sekolah 48 orang. Pengambilan sampel dilakukan secara rambang sederhana. Ukuran sampel dalam penelitian ini sebanyak 43 pengawas sekolah sebagai responden. Mengidentifikasi data sebagai outlier dari sekumpulan data yang menyimpang, terdapat 7 data pencilan sehingga data yang diinferensi sebanyak 37 orang. Instrumen yang digunakan berupa kuesioner. Pengembangan instrumen dilakukan mulai dari menyusun indikator, kisi-kisi instrumen, kemudian butir-butir instrumen yang di validasi isi, analisis butir secara kualitatif sehingga instrumen siap digunakan. Data dianalisis dengan menggunakan analisis deskriptif dan analisis inferensial. Hasil analisis deskriptif menunjukkan bahwa lingkungan kerja, motivasi kerja dan kinerja pengawas sekolah berada pada kategori baik. Hasil analisis inferensial menunjukkan bahwa: (1) Lingkungan kerja tidak mempunyai hubungan yang positif dan signifikan dengan kinerja pengawas SMA/SMK, (2) Motivasi kerja mempunyai hubungan yang positif dan signifikan dengan kinerja pengawas SMA/SMK, (3) Lingkungan kerja dan motivasi kerja mempunyai hubungan yang positif dan signifikan dengan Kinerja pengawas SMA/SMK, (4) Lingkungan kerja tidak mempunyai hubungan yang positif dan signifikan dengan kinerja pengawas SMA/SMK apabila motivasi kerja dikontrol, (5) Motivasi kerja mempunyai hubungan yang positif dan signifikan dengan kinerja pengawas SMA/SMK apabila lingkungan kerja pengawas dikontrol

Input estimation for extended-release formulations exemplified with exenatide

Estimating the in vivo absorption profile of a drug is essential when developing extended-release medications. Such estimates can be obtained by measuring plasma concentrations over time and inferring the absorption from a model of the drug’s pharmacokinetics. Of particular interest is to predict the bioavailability—the fraction of the drug that is absorbed and enters the systemic circulation. This paper presents a framework for addressing this class of estimation problems and gives advice on the choice of method. In parametric methods, a model is constructed for the absorption process, which can be difficult when the absorption has a complicated profile. Here, we place emphasis on non-parametric methods that avoid making strong assumptions about the absorption. A modern estimation method that can address very general input-estimation problems has previously been presented. In this method, the absorption profile is modeled as a stochastic process, which is estimated using Markov chain Monte Carlo techniques. The applicability of this method for extended-release formulation development is evaluated by analyzing a dataset of Bydureon, an injectable extended-release suspension formulation of exenatide, a GLP-1 receptor agonist for treating diabetes. This drug is known to have non-linear pharmacokinetics. Its plasma concentration profile exhibits multiple peaks, something that can make parametric modeling challenging, but poses no major difficulties for non-parametric methods. The method is also validated on synthetic data, exploring the effects of sampling and noise on the accuracy of the estimates

Parameter identifiability of fundamental pharmacodynamic models

Issues of parameter identifiability of routinely used pharmacodynamics models are considered in this paper. The structural identifiability of 16 commonly applied pharmacodynamic model structures was analyzed analytically, using the input-output approach. Both fixed-effects versions (non-population, no between-subject variability) and mixed-effects versions (population, including between-subject variability) of each model structure were analyzed. All models were found to be structurally globally identifiable under conditions of fixing either one of two particular parameters. Furthermore, an example was constructed to illustrate the importance of sufficient data quality and show that structural identifiability is a prerequisite, but not a guarantee, for successful parameter estimation and practical parameter identifiability. This analysis was performed by generating artificial data of varying quality to a structurally identifiable model with known true parameter values, followed by re-estimation of the parameter values. In addition, to show the benefit of including structural identifiability as part of model development, a case study was performed applying an unidentifiable model to real experimental data. This case study shows how performing such an analysis prior to parameter estimation can improve the parameter estimation process and model performance. Finally, an unidentifiable model was fitted to simulated data using multiple initial parameter values, resulting in highly different estimated uncertainties. This example shows that although the standard errors of the parameter estimates often indicate a structural identifiability issue, reasonably “good” standard errors may sometimes mask unidentifiability issues

Isolated spin qubits in SiC with a high-fidelity infrared spin-to-photon interface

The divacancies in SiC are a family of paramagnetic defects that show promise for quantum communication technologies due to their long-lived electron spin coherence and their optical addressability at near-telecom wavelengths. Nonetheless, a mechanism for high-fidelity spin-to-photon conversion, which is a crucial prerequisite for such technologies, has not yet been demonstrated. Here we demonstrate a high-fidelity spin-to-photon interface in isolated divacancies in epitaxial films of 3C-SiC and 4H-SiC. Our data show that divacancies in 4H-SiC have minimal undesirable spin-mixing, and that the optical linewidths in our current sample are already similar to those of recent remote entanglement demonstrations in other systems. Moreover, we find that 3C-SiC divacancies have millisecond Hahn-echo spin coherence time, which is among the longest measured in a naturally isotopic solid. The presence of defects with these properties in a commercial semiconductor that can be heteroepitaxially grown as a thin film on shows promise for future quantum networks based on SiC defects.Comment: 26 pages, 4 figure

Diffusive molecular communication with a spheroidal receiver for organ-on-chip systems

Realistic models of the components and processes are required for molecular communication (MC) systems. In this paper, a spheroidal receiver structure is proposed for MC that is inspired by the 3D cell cultures known as spheroids being widely used in organ-on-chip systems. A simple diffusive MC system is considered where the spheroidal receiver and a point source transmitter are in an unbounded fluid environment. The spheroidal receiver is modeled as a porous medium for diffusive signaling molecules, then its boundary conditions and effective diffusion coefficient are characterized. It is revealed that the spheroid amplifies the diffusion signal, but also disperses the signal which reduces the information communication rate. Furthermore, we analytically formulate and derive the concentration Green’s function inside and outside the spheroid in terms of infinite series-forms that are confirmed by a particle-based simulator (PBS)

Antisense Therapy Attenuates Phospholamban p.(Arg14del) Cardiomyopathy in Mice and Reverses Protein Aggregation

Inherited cardiomyopathy caused by the p.(Arg14del) pathogenic variant of the phospholamban (PLN) gene is characterized by intracardiomyocyte PLN aggregation and can lead to severe dilated cardiomyopathy. We recently reported that pre-emptive depletion of PLN attenuated heart failure (HF) in several cardiomyopathy models. Here, we investigated if administration of a Pln-targeting antisense oligonucleotide (ASO) could halt or reverse disease progression in mice with advanced PLN-R14del cardiomyopathy. To this aim, homozygous PLN-R14del (PLN-R14 (Δ/Δ)) mice received PLN-ASO injections starting at 5 or 6 weeks of age, in the presence of moderate or severe HF, respectively. Mice were monitored for another 4 months with echocardiographic analyses at several timepoints, after which cardiac tissues were examined for pathological remodeling. We found that vehicle-treated PLN-R14 (Δ/Δ) mice continued to develop severe HF, and reached a humane endpoint at 8.1 ± 0.5 weeks of age. Both early and late PLN-ASO administration halted further cardiac remodeling and dysfunction shortly after treatment start, resulting in a life span extension to at least 22 weeks of age. Earlier treatment initiation halted disease development sooner, resulting in better heart function and less remodeling at the study endpoint. PLN-ASO treatment almost completely eliminated PLN aggregates, and normalized levels of autophagic proteins. In conclusion, these findings indicate that PLN-ASO therapy may have beneficial outcomes in PLN-R14del cardiomyopathy when administered after disease onset. Although existing tissue damage was not reversed, further cardiomyopathy progression was stopped, and PLN aggregates were resolved