Double Donor Research Articles

A modifiable double donor based on bis(N-ethyl-N-hydroxyethyl)aniline for organic optical nonlinear chromophores

A strong modifiable double donor based on a bis(N-ethyl-N-hydroxyethyl)aniline-derived structure was developed and applied to nonlinear optical materials which show a large r33 value of 351 pm V−1 for the first time.

Lung Transplant Type and Donor Age in Idiopathic Pulmonary Fibrosis: A Single Center Study

Idiopathic pulmonary fibrosis (IPF) accounts for a marked proportion of diagnoses on the US lung transplant (LTx) list. The effects of single (SLT) versus double LTx (DLT) and lung donor age on survival in IPF remain unclear and were investigated in this study. We retrospectively assessed survival of LTx recipients with IPF at a single institution from February 2012-March 2020. Survival was analyzed and compared between LTx types (SLT and DLT), donor ages, and the combined groups (LTx type & donor age) using Kaplan-Meier survival analysis and compared by log-rank test. P-values less than 0.05 were considered significant. Of 744 LTx patients at our institution, 307 (41.3%) were diagnosed with IPF, of which 208 (67.8%) were SLT, and 97 (31.6%) were DLT (2 excluded patients underwent heart-lung transplantation). There was no significant difference in survival due to LTx type (P = 0.41) or for patients with donor age <50 or ≥50 y (P = 0.46). Once stratified by both LTx type and donor age, analysis showed no significant difference in survival between the four groups (P = 0.69). With ethical consideration for organ allocation, as the average age of the US population increases, donor lungs aged ≥50 are an increasingly useful resource in LTx. Our findings suggest donor age and LTx type do not significantly affect survival. Therefore, SLT, and donor lungs aged ≥50 ought to be more readily considered as non-inferior options for LTx in patients with IPF.

Infrared absorption cross sections, and oscillator strengths of interstitial and substitutional double donors in silicon

Infrared absorption cross sections and corresponding oscillator strengths of several intracenter transitions of double donors in silicon, interstitial magnesium (Mg; group IIA) and substitutional chalcogens (Ch = S; Se; group VI), were determined for impurity densities in the ranges $1\ifmmode\times\else\texttimes\fi{}{10}^{14}--1.6\ifmmode\times\else\texttimes\fi{}{10}^{15}\phantom{\rule{0.16em}{0ex}}\mathrm{atoms}/\mathrm{c}{\mathrm{m}}^{3}$ for Mg and $2\ifmmode\times\else\texttimes\fi{}{10}^{13}--2\ifmmode\times\else\texttimes\fi{}{10}^{16}\phantom{\rule{0.16em}{0ex}}\mathrm{atoms}/\mathrm{c}{\mathrm{m}}^{3}$ for chalcogens. The concentrations of electrically active atomic and diatomic donor centers were derived from the Hall effect measurements. The experimental integrated cross sections were obtained from low-temperature impurity absorption spectra. The oscillator strengths of related donor transitions were derived and compared with those for shallow single donors in silicon, both determined experimentally and predicted theoretically. The transitions of oscillator strengths of double donors follow the decreasing trend with decreasing radius of donor ground states and increasing an impurity binding energy.

Ultrasensitive Quantitation of Genomic Chimerism by Single-Molecule Molecular Inversion Probe Capture and High-Throughput Sequencing of Copy Number Deletion Polymorphisms

Genomic chimerism represents co-existing cells with different genotypes and has diagnostic significance in transplant engraftment monitoring, residual cancer detection, and other contexts. We previously described an approach to chimerism detection by interrogating variably present or absent genomic loci using single-molecule molecular inversion probes (smMIPs) and next-generation sequencing, which provided ultrasensitive limits of detection (<1 in 10,000 cells) but was not reliably quantitative. Herein, smMIP testing was modified to accurately quantitate chimeric cells by incorporating copy number neutral control loci for data normalization and computationally modeling cell mixtures from individual-specific genotypes. Data demonstrate precision and accuracy over three orders of magnitude (0.01% to 50% chimerism). Seventy hematopoietic stem cell transplant specimens from single (n=42) or double (n=28) donors were evaluated, benchmarking smMIP against conventional variable number tandem repeat (VNTR) analysis and an unrelated, ultrasensitive polymorphism-specific quantitative PCR (PS-qPCR) assay. Quantitative concordance of all three assays was high (P<0.0005, Pearson correlation coefficient), although smMIP correlated better with VNTR testing than PS-qPCR. smMIP and PS-qPCR collectively identified low-level chimerism in all specimens testing negative by VNTR (n=41 and n=45 of 48 specimens, respectively). This work demonstrates the feasibility of smMIP-based chimerism testing for quantitative and ultrasensitive measurement of genomic chimerism at practical levels approaching one in one million cells, and cross-validates the approach.

Effect of carbon, oxygen, and intrinsic defects on hydrogen-related donor concentration in proton irradiated n-type silicon

We investigated the effect of the concentration of carbon, oxygen, and irradiation-induced intrinsic defects on hydrogen-related donor (HD) concentration. Several n-type silicon wafers having different carbon and oxygen concentrations were irradiated with 2 MeV protons, subsequently annealed at 300–400 °C, and analyzed by spreading resistance profiling. The HD concentration had no correlation with carbon and oxygen concentration. Additionally, the HD concentration showed a strong increasing linear dependence with proton-irradiation dose at 350 and 400 °C and a square root dependence at 300 °C. In the decay process of HD concentration at 400 °C, fast- and slow-decay components were observed regardless of wafer type. Our results show that the HD formation is based on the interactive process of irradiation-induced intrinsic defects and hydrogen, rather than hydrogen-catalyzed thermal double donor formation. Magnetic-field-applied Czochralski (m:Cz) wafers with 300 mm diameter, which are critical for the production scaling of power devices, have a relatively higher oxygen concentration than conventional floating-zone wafers. Our results further suggest that controlling the intrinsic defect formation, rather than oxygen impurity concentration, is more important in realizing designed doping profiles with high accuracy and reproducibility for next-generation power devices using large-diameter m:Cz wafers as a standard starting material.

Complex Featuring Two Double Dative Bonds Between Carbon(0) and Uranium

Complex Featuring Two Double Dative Bonds Between Carbon(0) and Uranium

Ultrasensitive Detection of Amyloid β Oligomers Based on the "DD-A" FRET Binary Probes and Quadrivalent Cruciform DNA Nanostructure-Mediated Cascaded Amplifier.

The reported donor donor-acceptor ("DD-A") fluorescence resonance energy transfer (FRET) was typically achieved through random collisions and interactions of DNA molecules in the bulk solution, which has inevitable defects, including weak biological stability, slow reaction kinetics, and low hybridization efficiency. In order to overcome these deficiencies, this work developed a quadrivalent cruciform DNA nanostructure (qCDN)-mediated cascaded catalyzed hairpin assembly (CHA) amplifier for the fluorescence detection of amyloid β oligomer species (AβOs). First, four H1 and four H2 hairpins were assembled on one qCDN to obtain qCDNH1 and qCDNH2, respectively. In the presence of AβOs, strand C was released from the P1-C hybrid hairpin and then alternately opened qCDNH1 and qCDNH2 to trigger the qCDN-mediated CHA. As a result, double donors in H1 and one acceptor in H2 were mutually closed, and the porous DNA nanonet with a high loading of "DD-A" FRET binary probes was formed. The FRET efficiency was approximately 78%, and the initial reaction rate was 25-fold faster than the conventional CHA. The detection limit of AβOs was as low as 0.69 pM. The combination of the "DD-A" FRET binary probes and qCDN-mediated cascaded amplifier exhibited great promise for detecting biomarkers with trace levels.

Isolation of a Uranium(III)-Carbon Multiple Bond Complex.

Low‐valent uranium‐element multiple bond complexes remain scarce, though there is burgeoning interest regarding to their bonding and reactivity. Herein, isolation of a uranium(III)‐carbon double bond complex [(Cp*)2U(CDP)](BPh4) (1) comprising a tridentate carbodiphosphorane (CDP) was reported for the first time. Oxidation of 1 afforded the corresponding U(IV) complex [(Cp*)2U(CDP)](BPh4)2 (2). The distance between U and C in 2 is 2.481 Å, indicating the existence of a typical U=C double bond, which is further confirmed by quantum chemical calculations. Bonding analysis suggested that the CDP also serves as both σ‐ and π‐donor in complex 1, though a longer U−C bond (2.666(3) Å) is observed. It implies that 1 is the first isolable mononuclear uranium(III) carbene complex. Moreover, these results suggest that CDPs are promising ligands to establish other low‐valent f‐block metal‐carbon multiple bond complexes.

Optical and Structural Properties of Ga and in Co-Doped ZnO Nanocrystals Films

The impact of double donor doping on the crystal structure, emission and electrical resistivity has been studied in the ZnO:Ga:In films. The films were deposited by ultrasonic spray pyrolysis on a previously cleaned silicon substrate. To the study of double donor doping, two groups of samples were prepared. In the first group the In content was 1at% and the Ga contents were varied in the range 0.5-3.0at.%. In the second group the In content was 2at% and the Ga content were changed in the range 0.5-2.5at%. To stimulate the film crystallization, all samples were annealed at 400oC for 2 hours in nitrogen flow 5l/min. The high quality nanocrystal (NC) films with the wurtzite-type crystal structure, bright near band edge (NBE) emission and the small intensity of defect related PL bands have been aobtained. The variation non monotonically of the ZnO crystal lattice parameters, as well as the PL intensities of NBE emission bands has been detected. The reasons for the parameter variation non monotonically and the optimal concentrations for the Ga/In double donor doping of ZnO NC films have been analyzed and discussed.Corresponding author E mail: braelf@hotmail.com

Chalcogen-doped zinc oxide nanoparticles for photocatalytic degradation of Rhodamine B under the irradiation of ultraviolet light

In the present work, the chalcogen (Se2+)-doped ZnO nanoparticles (SeZO-NPs) were synthesized using sol-gel precipitation method and tested for photocatalytic degradation of Rhodamine B (RhB). X-ray diffraction pattern of SeZO-NPs showed the hexagonal wurtzite crystal structure regardless of Se concentration. The band edge and defect-level emissions of SeZO-NPs were determined by using the photoluminescence spectra with the excitation source of 370 nm. The bandgap, Eg, of SeZO-NPs was measured from diffused reflectance spectroscopy, which increased from 3.22 to 3.26 eV as Se concentration increased from 0 to 10 wt.%. The highest specific surface area and lowest pore size of 5-SeZO-NPs were observed to be 36.42 m2/g and 13.48 nm, respectively. The photocatalytic degradation of SeZO-NPs was measured under the illumination of ultraviolet (UV) light. The double donor (Se) played an important role toward photodegradation of RhB via reducing the recombination of charge carriers. The highest photocatalytic degradation (98.23%) and mineralization were achieved for the sample 5-SeZO (Se: 5 wt.%). The improved photocatalytic performance of 5-SeZO was attributed to the optimum Se dopant concentration for the production of more reactive oxygen species because of effective separation of charge carriers in UV light.

Effects of Thermal Annealing on the Properties of Zirconium-Doped MgxZn1-XO Films Obtained through Radio-Frequency Magnetron Sputtering.

Zirconium-doped MgxZn1−xO (Zr-doped MZO) mixed-oxide films were investigated, and the temperature sensitivity of their electric and optical properties was characterized. Zr-doped MZO films were deposited through radio-frequency magnetron sputtering using a 4-inch ZnO/MgO/ZrO2 (75/20/5 wt%) target. Hall measurement, X-ray diffraction (XRD), transmittance, and X-ray photoelectron spectroscopy (XPS) data were obtained. The lowest sheet resistance, highest mobility, and highest concentration were 1.30 × 103 Ω/sq, 4.46 cm2/Vs, and 7.28 × 1019 cm−3, respectively. The XRD spectra of the as-grown and annealed Zr-doped MZO films contained MgxZn1−xO(002) and ZrO2(200) coupled with Mg(OH)2(101) at 34.49°, 34.88°, and 38.017°, respectively. The intensity of the XRD peak near 34.88° decreased with temperature because the films that segregated Zr4+ from ZrO2(200) increased. The absorption edges of the films were at approximately 348 nm under 80% transmittance because of the Mg content. XPS revealed that the amount of Zr4+ increased with the annealing temperature. Zr is a potentially promising double donor, providing up to two extra free electrons per ion when used in place of Zn2+.

Optical and Structural Properties of Ga and in Co-Doped ZnO Nanocrystals Films

The impact of double donor doping on the crystal structure, emission, and electrical resistivity has been studied in the ZnO:Ga:In films. The films were deposited by ultrasonic spray pyrolysis on a previously cleaned silicon substrate. To the study of double donor doping, two groups of samples were prepared. In the first group the In content was 1at% and the Ga contents were varied in the range 0.5-3.0at.%. In the second group the In content was 2at% and the Ga content were changed in the range 0.5-2.5at%. To stimulate the film crystallization, all samples were annealed at 400oC for 2 hours in nitrogen flow 5l/min. The high quality nanocrystal (NC) films with the wurtzite-type crystal structure, bright near band edge (NBE) emission and the small intensity of defect related PL bands have been obtained. The variation non monotonically of the ZnO crystal lattice parameters, as well as the PL intensities of NBE emission bands has been detected. The reasons for the parameter variation non monotonically and the optimal concentrations for the Ga/In double donor doping of ZnO NC films have been analyzed and discussed.

Introduction of mutations in plants with prime editing.

The emergence of a clustered regularly interspaced short palindromic repeats/CRISPR-associated proteins (CRISPR/Cas) system has had a revolutionary impact on plant biology. However, this system and further developed base editing are limited by their inherent imperfection. Prime editing, a just arrival technology based on CRISPR/Cas, can directly and precisely edit a specified DNA site without double strand breaks and donor DNA by integrating an engineered reverse transcriptase (RT) with a catalytically impaired Cas9 endonuclease and introducing genetic information into prime editing guide RNA (pegRNA). In addition, it has a wider range of editing types than base editing and can install all types of editing theoretically. Prime editing was originally developed in mammalian cells and has recently been applied to plants. Here, we describe the origin of prime editing and compare it with traditional CRISPR/Cas9 and base editing; then, we exemplify it in plants, including strategies and methods. Accordingly, we generate the overall procedures of prime editing to provide instructions for its application. Furthermore, we summarize its improvements in the approach, such as optimizing the length of a primer binding site and RT template, as well as pursuing an optimal nicking site in the unedited sequence. Finally, we discuss the potential impact on domestication and improvement of agricultural crops, sustainable utilization of medicinal plants, cultivation of varieties of horticultural plants, and revelation of the genetic code, in order to offer a reference for the further study and development of prime editing.

A Single Center Study of Donor Age & Lung Transplant Type in Idiopathic Pulmonary Fibrosis

<h3>Purpose</h3> Idiopathic pulmonary fibrosis (IPF) accounts for the largest proportion of diagnoses on the US lung transplant (LTx) list. LTx type (single vs double) and donor age are associated with differences in outcomes, yet their independent and combined effects in patients with IPF remain unclear and are investigated in this study. <h3>Methods</h3> This study retrospectively analyzed survival of patients with IPF receiving LTx at a single center from Feb-2012 to Mar-2020. LTx recipients were grouped by single (SLT) or double (DLT) LTx type and donor lung age <50 or 50≥ years. Survival outcomes were measured using Kaplan-Meier (KM) survival analysis and compared by log-rank test. Cox proportional hazards modeling was used to control for significantly associated variables, including lung allocation score, surgical approach, pump, warm ischemic time (avg), donor height, and prior percutaneous coronary intervention and coronary artery bypass grafting. <h3>Results</h3> Of 742 LTx patients, 305 (41%) were diagnosed with IPF, of which 204 (67%) were SLT and 97 (32%) were DLT (4 patients underwent either heart-lung transplant or single-sequential LTx and were excluded). There was no significant difference in survival due to LTx type (p=0.368). Similarly, no significant difference in survival was found for patients with donor age <50 or 50≥ years (p=0.298). Of grouped patients with IPF, there were 12 DLT and donor age 50≥, 35 SLT and donor age 50≥, 85 DLT and donor age <50, and 169 SLT and donor age <50. KM analysis showed no significant difference (p=0.455) in survival between the four groups, though DLT and donor age 50≥ had increased mean and median survival days comparatively. Cox regression suggested none of the covariates significantly affected survival. <h3>Conclusion</h3> Demand for donor lungs far exceeds supply, and with IPF accounting for a large percentage of this need, finding effective sources of supply has become increasingly important. Use of SLT and donors aged 50≥ can serve as important supply sources with non-inferior survival outcomes.

Controlling Ratios of Plasmid-Based Double Cut Donor and CRISPR/Cas9 Components to Enhance Targeted Integration of Transgenes in Chinese Hamster Ovary Cells.

Chinese hamster ovary (CHO) cells are the most valuable expression host for the commercial production of biotherapeutics. Recent trends in recombinant CHO cell-line development have focused on the site-specific integration of transgenes encoding recombinant proteins over random integration. However, the low efficiency of homology-directed repair upon transfection of Cas9, single-guide RNA (sgRNA), and the donor template has limited its feasibility. Previously, we demonstrated that a double-cut donor (DCD) system enables highly efficient CRISPR/Cas9-mediated targeted integration (TI) in CHO cells. Here, we describe several CRISPR/Cas9 vector systems based on DCD templates using a promoter trap-based TI monitoring cell line. Among them, a multi-component (MC) system consisting of an sgRNA/DCD vector and Cas9 expression vector showed an approximate 1.5-fold increase in knock-in (KI) efficiency compared to the previous DCD system, when a systematically optimized relative ratio of sgRNA/DCD and Cas9 vector was applied. Our optimization efforts revealed that concurrently increasing sgRNA and DCD components relative to Cas9 correlated positively with KI efficiency at a single KI site. Furthermore, we explored component bottlenecks, such as effects of sgRNA components and applicability of the MC system on simultaneous double KI. Taken together, we improved the DCD vector design by tailoring plasmid constructs and relative component ratios, and this system can be widely used in the TI strategy of transgenes, particularly in CHO cell line development and engineering.

Insulitis in the pancreas of non-diabetic organ donors under age 25 years with multiple circulating autoantibodies against islet cell antigens

Autoantibodies against islet cell antigens are routinely used to identify subjects at increased risk of symptomatic type 1 diabetes, but their relation to the intra-islet pathogenetic process that leads to positivity for these markers is poorly understood. We screened 556 non-diabetic organ donors (3 months to 24 years) for five different autoantibodies and found positivity in 27 subjects, 25 single- and two double autoantibody-positive donors. Histopathological screening of pancreatic tissue samples showed lesion characteristic for recent-onset type 1 diabetes in the two organ donors with a high-risk profile, due to their positivity for multiple autoantibodies and HLA-inferred risk. Inflammatory infiltrates (insulitis) were found in a small fraction of islets (<5%) and consisted predominantly of CD3+CD8+ T-cells. Islets with insulitis were found in close proximity to islets devoid of insulin-positivity; such pseudo-atrophic islets were present in multiple small foci scattered throughout the pancreatic tissue or were found to be distributed with a lobular pattern. Relative beta cell area in both single and multiple autoantibody-positive donors was comparable to that in autoantibody-negative controls. In conclusion, in organ donors under age 25 years, insulitis and pseudo-atrophic islets were restricted to multiple autoantibody-positive individuals allegedly at high risk of developing symptomatic type 1 diabetes, in line with reports in older age groups. These observations may give further insight into the early pathogenetic events that may culminate in clinically overt disease.

Organocatalytic Kinetic Resolution of N-Boc-Isoxazolidine-5-ones.

Easily accessible racemic N-Boc-isoxazolidine-5-ones undergo enantioselective alcoholysis promoted by double hydrogen bond donor amine organocatalysts, resulting in their effective kinetic resolution.

Bonding analysis of water clusters using quasi-atomic orbitals.

The quasi-atomic orbital (QUAO) bonding analysis introduced by Ruedenberg and co-workers is used to develop an understanding of the hydrogen bonds in small water clusters, from the dimer through the hexamer (bag, boat, book, cyclic, prism and cage conformers). Using kinetic bond orders as a metric, it is demonstrated that as the number of waters in simple cyclic clusters increases, the hydrogen bonds strengthen, from the dimer through the cyclic hexamer. However, for the more complex hexamer isomers, the strength of the hydrogen bonds varies, depending on whether the cluster contains double acceptors and/or double donors. The QUAO analysis also reveals the three-center bonding nature of hydrogen bonds in water clusters.

Density functional theory design of double donor dyes and electron transfer on dye/TiO2(101) composite systems for dye-sensitized solar cells.

In this work, we designed a series of double donor organic dyes, named ME101–ME106, based on experimentally synthesized dye WD8, and further investigated their electronic structure, the stability of the dye/TiO2 (101) systems, density of states (DOS) and absorption spectra using density functional theory (DFT) and time-dependent DFT (TDDFT). The molar extinction coefficients of all designed dyes are higher than WD8. It's fascinating that ME106 exhibits a smallest energy gap and 75 nm redshifts compared to WD8. The results of calculations reveal that ME101–ME106/TiO2(101) surfaces are more stable than WD8, double donor dyes have sufficient electron injection driving force and have very strong transfer electron ability. It is expected that the design of double donors can provide a new understanding and guidance for the investigation of high efficiency dye-sensitized devices.

Оптические сечения поглощения и силы осцилляторов двойного донора магния в кремнии

The optical properties of magnesium impurity in silicon, whose atoms at interstitial positions in the lattice are deep double donors with an ionization energy of 107.56 meV in the neutral state, were studied. For optical transitions from the ground state of a neutral center to the excited levels 2p0 and 2p, the absorption cross sections and oscillator strengths were determined. These parameters were calculated from the impurity absorption spectra that were measured at T  K in samples with different magnesium concentrations. The deep donor content in the samples was determined using Hall effect measurements in the temperature range 78–300 K. The obtained characteristics of intracenter transitions in magnesium were compared with the corresponding literature data for shallow Group V donors in silicon, which are substitutional impurities. It was found that the optical characteristics of the investigated transitions in magnesium are consistent with the dependences of the corresponding parameters on the ionization energy for shallow donors, extrapolated to the region of larger electron binding energies.