93 research outputs found
Dilute magnetic semiconductor and half metal behaviors in 3d transition-metal doped black and blue phosphorenes: a first-principles study
We present first-principles density-functional calculations for the
structural, electronic, and magnetic properties of substitutional 3d transition
metal (TM) impurities in two-dimensional black and blue phosphorenes. We find
that the magnetic properties of such substitutional impurities can be
understood in terms of a simple model based on the Hund's rule. The TM-doped
black phosphorenes with Ti, V, Cr, Mn, Fe and Ni impurities show dilute
magnetic semiconductor (DMS) properties while those with Sc and Co impurities
show nonmagnetic properties. On the other hand, the TM-doped blue phosphorenes
with V, Cr, Mn and Fe impurities show DMS properties, those with Ti and Ni
impurities show half-metal properties, whereas Sc and Co doped systems show
nonmagnetic properties. We identify two different regimes depending on the
occupation of the hybridized electronic states of TM and phosphorous atoms: (i)
bonding states are completely empty or filled for Sc- and Co-doped black and
blue phosphorenes, leading to non-magnetic; (ii) non-bonding d states are
partially occupied for Ti-, V-, Cr-, Mn-, Fe- and Ni-doped black and blue
phosphorenes, giving rise to large and localized spin moments. These results
provide a new route for the potential applications of dilute magnetic
semiconductor and half-metal in spintronic devices by employing black and blue
phosphorenes.Comment: 9 pages, 7 figure
DiffFit: Unlocking Transferability of Large Diffusion Models via Simple Parameter-Efficient Fine-Tuning
Diffusion models have proven to be highly effective in generating
high-quality images. However, adapting large pre-trained diffusion models to
new domains remains an open challenge, which is critical for real-world
applications. This paper proposes DiffFit, a parameter-efficient strategy to
fine-tune large pre-trained diffusion models that enable fast adaptation to new
domains. DiffFit is embarrassingly simple that only fine-tunes the bias term
and newly-added scaling factors in specific layers, yet resulting in
significant training speed-up and reduced model storage costs. Compared with
full fine-tuning, DiffFit achieves 2 training speed-up and only needs
to store approximately 0.12\% of the total model parameters. Intuitive
theoretical analysis has been provided to justify the efficacy of scaling
factors on fast adaptation. On 8 downstream datasets, DiffFit achieves superior
or competitive performances compared to the full fine-tuning while being more
efficient. Remarkably, we show that DiffFit can adapt a pre-trained
low-resolution generative model to a high-resolution one by adding minimal
cost. Among diffusion-based methods, DiffFit sets a new state-of-the-art FID of
3.02 on ImageNet 512512 benchmark by fine-tuning only 25 epochs from a
public pre-trained ImageNet 256256 checkpoint while being 30
more training efficient than the closest competitor.Comment: Tech Repor
Study on ultrasound-guided thyroid fine needle puncture assisted by rapid on-side evaluation
Objective·To explore the clinical effect of ultrasound-guided fine needle aspiration cytology assisted by rapid on-side evaluation (ROSE).Methods·The data of patients with thyroid nodules diagnosed in Gongli Hospital of Shanghai Pudong New Area from January 2019 to December 2022 were retrospectively analyzed (n=874). According to cytological detection methods, they were divided into ROSE+thinprep cytologic test (TCT) group (n=469) and cell smear (CS)+TCT group (n=405). In the ROSE+TCT group, the tissue and cell samples of ROSE were detected by Diff-Quik staining and continue puncturing until the specimen was satisfied. In the CS+TCT group, the tissue and cell samples were detected by hematoxylin-eosin staining (H-E staining) + Pap staining. Cytologic diagnosis was made according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) cytologic classification criteria, and the cell dissatisfaction rates and clinical outcomes of the 2 methods were compared.Results·The dissatisfaction rates of the ROSE+TCT group and CS+TCT group were 2.4% and 14.1%, respectively, with statistical significance (P=0.000). The smear cells of the ROSE+TCT group were concentrated, and the structure was clear and easy to observe. The samples with a cytologic diagnosis of grade Ⅲ and above were prepared as cell wax blocks to improve the efficiency of subsequent diagnosis. The cells of the CS+TCT group could not produce wax blocks due to the small numbers of cells. The puncture times of the ROSE+TCT group were significantly different from that of the CS+TCT group (P=0.011).Conclusion·The ultrasound-guided thyroid fine needle aspiration assisted by rapid on-site assessment method can assess the effective number of cells in the specimen on the spot, give feedback to the puncturing doctors on the spot, meet the diagnostic accuracy requirements of pathologists by collecting a sufficient number of cells, reduce the number of punctures and treatment time, and play a good auxiliary role in the diagnosis and follow-up examination of clinicians
Proteomic aging clock predicts mortality and risk of common age-related diseases in diverse populations
Circulating plasma proteins play key roles in human health and can potentially be used to measure biological age, allowing risk prediction for age-related diseases, multimorbidity and mortality. Here we developed a proteomic age clock in the UK Biobank (n = 45,441) using a proteomic platform comprising 2,897 plasma proteins and explored its utility to predict major disease morbidity and mortality in diverse populations. We identified 204 proteins that accurately predict chronological age (Pearson r = 0.94) and found that proteomic aging was associated with the incidence of 18 major chronic diseases (including diseases of the heart, liver, kidney and lung, diabetes, neurodegeneration and cancer), as well as with multimorbidity and all-cause mortality risk. Proteomic aging was also associated with age-related measures of biological, physical and cognitive function, including telomere length, frailty index and reaction time. Proteins contributing most substantially to the proteomic age clock are involved in numerous biological functions, including extracellular matrix interactions, immune response and inflammation, hormone regulation and reproduction, neuronal structure and function and development and differentiation. In a validation study involving biobanks in China (n = 3,977) and Finland (n = 1,990), the proteomic age clock showed similar age prediction accuracy (Pearson r = 0.92 and r = 0.94, respectively) compared to its performance in the UK Biobank. Our results demonstrate that proteomic aging involves proteins spanning multiple functional categories and can be used to predict age-related functional status, multimorbidity and mortality risk across geographically and genetically diverse populations
Internet-Based HIV Self-Testing Among Men Who Have Sex With Men Through Pre-exposure Prophylaxis: 3-Month Prospective Cohort Analysis From China.
BACKGROUND: Routine HIV testing accompanied with pre-exposure prophylaxis (PrEP) requires innovative support in a real-world setting. OBJECTIVE: This study aimed to determine the usage of HIV self-testing (HIVST) kits and their secondary distribution to partners among men who have sex with men (MSM) in China, who use PrEP, in an observational study between 2018 and 2019. METHODS: In 4 major cities in China, we prospectively followed-up MSM from the China Real-world oral PrEP demonstration study, which provides daily or on-demand PrEP for 12 months, to assess the usage and secondary distribution of HIVST on quarterly follow-ups. Half of the PrEP users were randomized to receive 2 HIVSTs per month in addition to quarterly facility-based HIV testing. We evaluated the feasibility of providing HIVST to PrEP users. RESULTS: We recruited 939 MSM and randomized 471 to receive HIVST, among whom 235 (49.9%) were daily and 236 (50.1%) were on-demand PrEP users. At baseline, the median age was 29 years, 390 (82.0%) men had at least college-level education, and 119 (25.3%) had never undergone facility-based HIV testing before. Three months after PrEP initiation, 341 (74.5%) men had used the HIVST provided to them and found it very easy to use. Among them, 180 of 341 (52.8%) men had distributed the HIVST kits it to other MSM, and 132 (51.6%) among the 256 men who returned HIVST results reported that used it with their sexual partners at the onset of intercourse. Participants on daily PrEP were more likely to use HIVST (adjusted hazard ratio=1.3, 95% CI 1.0-1.6) and distribute HIVST kits (adjusted hazard ratio=1.3, 95% CI 1.1-1.7) than those using on-demand PrEP. CONCLUSIONS: MSM who used PrEP had a high rate of usage and secondary distribution of HIVST kits, especially among those on daily PrEP, which suggested high feasibility and necessity for HIVST after PrEP initiation. Assuming that fourth-generation HIVST kits are available, HIVST may be able to replace facility-based HIV testing to a certain extent. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR1800020374; https://www.chictr.org.cn/showprojen.aspx?proj=32481. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1136/bmjopen-2019-036231
The Thermoanaerobacter Glycobiome Reveals Mechanisms of Pentose and Hexose Co-Utilization in Bacteria
Author Summary Renewable liquid fuels derived from lignocellulosic biomass could alleviate global energy shortage and climate change. Cellulose and hemicellulose are the main components of lignocellulosic biomass. Therefore, the ability to simultaneously utilize pentose and hexose (i.e., co-utilization) has been a crucial challenge for industrial microbes producing lignocellulosic biofuels. Certain thermoanaerobic bacteria demonstrate this unusual talent, but the genetic foundation and molecular mechanism of this process remain unknown. In this study, we reconstructed the structure and dynamics of the first genome-wide carbon utilization network of thermoanaerobes. This transcriptome-based co-expression network reveals that glucose, xylose, fructose, and cellobiose catabolism are each featured on distinct functional modules. Furthermore, the dynamics of the network suggests a distinct yet collaborative nature between glucose and xylose catabolism. In addition, we experimentally demonstrated that these novel network-derived features can be rationally exploited for product-yield enhancement via optimized timing and balanced loading of the carbon supply in a substrate-specific manner. Thus, the newly discovered modular and precisely regulated network elucidates unique features of thermoanaerobic glycobiomes and reveals novel perturbation strategies and targets for the enhanced thermophilic production of lignocellulosic biofuels.Yeshttp://www.plosgenetics.org/static/editorial#pee
Leveraging base-pair mammalian constraint to understand genetic variation and human disease
[INTRODUCTION] Thousands of genetic variants have been associated with human diseases and traits through genome-wide association studies (GWASs). Translating these discoveries into improved therapeutics requires discerning which variants among hundreds of candidates are causally related to disease risk. To date, only a handful of causal variants have been confirmed. Here, we leverage 100 million years of mammalian evolution to address this major challenge.[RATIONALE] We compared genomes from hundreds of mammals and identified bases with unusually few variants (evolutionarily constrained). Constraint is a measure of functional importance that is agnostic to cell type or developmental stage. It can be applied to investigate any heritable disease or trait and is complementary to resources using cell type– and time point–specific functional assays like Encyclopedia of DNA Elements (ENCODE) and Genotype-Tissue Expression (GTEx).[RESULTS] Using constraint calculated across placental mammals, 3.3% of bases in the human genome are significantly constrained, including 57.6% of coding bases. Most constrained bases (80.7%) are noncoding. Common variants (allele frequency ≥ 5%) and low-frequency variants (0.5% ≤ allele frequency < 5%) are depleted for constrained bases (1.85 versus 3.26% expected by chance, P < 2.2 × 10−308). Pathogenic ClinVar variants are more constrained than benign variants (P < 2.2 × 10−16).
The most constrained common variants are more enriched for disease single-nucleotide polymorphism (SNP)–heritability in 63 independent GWASs. The enrichment of SNP-heritability in constrained regions is greater (7.8-fold) than previously reported in mammals and is even higher in primates (11.1-fold). It exceeds the enrichment of SNP-heritability in nonsynonymous coding variants (7.2-fold) and fine-mapped expression quantitative trait loci (eQTL)–SNPs (4.8-fold). The enrichment peaks near constrained bases, with a log-linear decrease of SNP-heritability enrichment as a function of the distance to a constrained base.
Zoonomia constraint scores improve functionally informed fine-mapping. Variants at sites constrained in mammals and primates have greater posterior inclusion probabilities and higher per-SNP contributions. In addition, using both constraint and functional annotations improves polygenic risk score accuracy across a range of traits. Finally, incorporating constraint information into the analysis of noncoding somatic variants in medulloblastomas identifies new candidate driver genes.[CONCLUSION] Genome-wide measures of evolutionary constraint can help discern which variants are functionally important. This information may accelerate the translation of genomic discoveries into the biological, clinical, and therapeutic knowledge that is required to understand and treat human disease.This work was funded by the Swedish Research Council and Knut and Alice Wallenberg Foundation, Swedish Cancer Society, Swedish Childhood Cancer Fund, National Institute of Mental Health (NIMH) U01MH116438, Gladstone Institutes, National Institute on Drug Abuse (NIDA) DP1DA04658501, NIDA F30DA053020, University College Dublin (UCD) Ad Astra Fellowship, and National Human Genome Research Institute (NHGRI) R01HG008742 and U41HG002371. S.G. was supported by National Institutes of Health (NIH) grants R00 HG010160 and R35 GM147789. Y.L. was supported by NIH U01 HG011720. Additional support was provided by the Australian National Health and Medical Research Council (1113400, 1173790, and 1177268). L.M.H. was supported by NIH grants MH118278, MH124839, and ES033630. P.F.S. was supported by the Swedish Research Council (Vetenskapsrådet, award D0886501). This study makes use of data from the UK Biobank (project ID 12505).Peer reviewe
Enhancement of the Activity of Electrochemical Oxidation of BPS by Nd-Doped PbO2 Electrodes: Performance and Mechanism
The electrochemical oxidation processes have attracted tremendous attention on the destruction of toxic and non-biodegradable organics. A series of neodymium (Nd)-doped PbO2 electrodes (Ti/PbO2-Nd) were synthesized through a pulse electrodeposition method, and its activity of bisphenol S (BPS) removal was further examined. The morphologies and structures were characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM) and an energy dispersive spectrometer (EDS). The performance, energy consumption and mechanism of electrochemical oxidation of BPS by Ti/PbO2-Nd electrode were also discussed. Compared to the traditional Ti/PbO2 electrode, the Ti/PbO2-Nd enables finer crystal particles, facilitating the oxygen evolution overpotential (OEP) from 1.41V to 1.55V and the generation of hydroxyl radicals (•OH). Moreover, lower duty cycles during the preparation of the electrode also contribute to the tapering size of crystals. The results show that the Ti/PbO2-Nd electrode exhibits relatively high activity in the anodic oxidation of BPS. Over 95% of BPS could be removed with the current density of 15 mA cm−2. Moreover, the energy consumption of BPS degradation on Ti/PbO2-Nd electrode is 60.26 kWh m−3, much lower than that on Ti/PbO2 electrode (95.45 kWh m−3). To conclude, the Ti/PbO2-Nd electrode has been proven to be a promising material for BPS removal
- …