Digital Commons Network^™

Split Learning For Distributed Collaborative Training Of Deep Learning Models In Health Informatics, Zhuohang Li, Chao Yan, Xinmeng Zhang, Gharib Gharibi, Zhijun Yin, Xiaoqian Jiang, Bradley A Malin

Faculty, Staff and Student Publications

Deep learning continues to rapidly evolve and is now demonstrating remarkable potential for numerous medical prediction tasks. However, realizing deep learning models that generalize across healthcare organizations is challenging. This is due, in part, to the inherent siloed nature of these organizations and patient privacy requirements. To address this problem, we illustrate how split learning can enable collaborative training of deep learning models across disparate and privately maintained health datasets, while keeping the original records and model parameters private. We introduce a new privacy-preserving distributed learning framework that offers a higher level of privacy compared to conventional federated learning. We …

Local Contrastive Learning For Medical Image Recognition, Syed A Rizvi, Ruixiang Tang, Xiaoqian Jiang, Xiaotian Ma, Xia Hu

Faculty, Staff and Student Publications

The proliferation of Deep Learning (DL)-based methods for radiographic image analysis has created a great demand for expert-labeled radiology data. Recent self-supervised frameworks have alleviated the need for expert labeling by obtaining supervision from associated radiology reports. These frameworks, however, struggle to distinguish the subtle differences between different pathologies in medical images. Additionally, many of them do not provide interpretation between image regions and text, making it difficult for radiologists to assess model predictions. In this work, we propose Local Region Contrastive Learning (LRCLR), a flexible fine-tuning framework that adds layers for significant image region selection as well as cross-modality …

Syllable-Pbwt For Space-Efficient Haplotype Long-Match Query, Victor Wang, Ardalan Naseri, Shaojie Zhang, Degui Zhi

Faculty, Staff and Student Publications

MOTIVATION: The positional Burrows-Wheeler transform (PBWT) has led to tremendous strides in haplotype matching on biobank-scale data. For genetic genealogical search, PBWT-based methods have optimized the asymptotic runtime of finding long matches between a query haplotype and a predefined panel of haplotypes. However, to enable fast query searches, the full-sized panel and PBWT data structures must be kept in memory, preventing existing algorithms from scaling up to modern biobank panels consisting of millions of haplotypes. In this work, we propose a space-efficient variation of PBWT named Syllable-PBWT, which divides every haplotype into syllables, builds the PBWT positional prefix arrays on …

Text Classification Of Cancer Clinical Trial Eligibility Criteria, Yumeng Yang, Soumya Jayaraj, Ethan Ludmir, Kirk Roberts

Faculty, Staff and Student Publications

Automatic identification of clinical trials for which a patient is eligible is complicated by the fact that trial eligibility are stated in natural language. A potential solution to this problem is to employ text classification methods for common types of eligibility criteria. In this study, we focus on seven common exclusion criteria in cancer trials: prior malignancy, human immunodeficiency virus, hepatitis B, hepatitis C, psychiatric illness, drug/substance abuse, and autoimmune illness. Our dataset consists of 764 phase III cancer trials with these exclusions annotated at the trial level. We experiment with common transformer models as well as a new pre-trained …

Use Gpt-J Prompt Generation With Roberta For Ner Models On Diagnosis Extraction Of Periodontal Diagnosis From Electronic Dental Records, Yao-Shun Chuang, Xiaoqian Jiang, Chun-Teh Lee, Ryan Brandon, Duong Tran, Oluwabunmi Tokede, Muhammad F Walji

Faculty, Staff and Student Publications

This study explored the usability of prompt generation on named entity recognition (NER) tasks and the performance in different settings of the prompt. The prompt generation by GPT-J models was utilized to directly test the gold standard as well as to generate the seed and further fed to the RoBERTa model with the spaCy package. In the direct test, a lower ratio of negative examples with higher numbers of examples in prompt achieved the best results with a F1 score of 0.72. The performance revealed consistency, 0.92-0.97 in the F1 score, in all settings after training with the RoBERTa model. …

A Novel Nih Research Grant Recommender Using Bert, Jie Zhu, Braja Gopal Patra, Hulin Wu, Ashraf Yaseen

Faculty, Staff and Student Publications

Research grants are important for researchers to sustain a good position in academia. There are many grant opportunities available from different funding agencies. However, finding relevant grant announcements is challenging and time-consuming for researchers. To resolve the problem, we proposed a grant announcements recommendation system for the National Institute of Health (NIH) grants using researchers' publications. We formulated the recommendation as a classification problem and proposed a recommender using state-of-the-art deep learning techniques: i.e. Bidirectional Encoder Representations from Transformers (BERT), to capture intrinsic, non-linear relationship between researchers' publications and grants announcements. Internal and external evaluations were conducted to assess the …

Data Mining Pipeline For Covid-19 Vaccine Safety Analysis Using A Large Electronic Health Record, Yan Huang, Xiaojin Li, Deepa Dongarwar, Hulin Wu, Guo-Qiang Zhang

Faculty, Staff and Student Publications

We developed a novel data mining pipeline that automatically extracts potential COVID-19 vaccine-related adverse events from a large Electronic Health Record (EHR) dataset. We applied this pipeline to Optum® de-identified COVID-19 EHR dataset containing COVID-19 vaccine records between December 11, 2020 and January 20, 2022. We compared post-vaccination diagnoses between the COVID-19 vaccine group and the influenza vaccine group among 553,682 individuals without COVID-19 infection. We extracted 1,414 ICD-10 diagnosis categories (first three ICD10 digits) within 180 days after the first dose of the COVID-19 vaccine. We then ranked the diagnosis codes using the adverse event rates and adjusted odds …

Selection And Validation Of Optimal Reference Genes For Rt-Qpcr Analyses In Aphidoletes Aphidimyza Rondani (Diptera: Cecidomyiidae), Xiu-Xian Shen, Guo-Qiang Zhang, Yu-Xin Zhao, Xiao-Xiao Zhu, Xiao-Fei Yu, Mao-Fa Yang, Feng Zhang

Faculty, Staff and Student Publications

Aphidoletes aphidimyza is a predator that is an important biological agent used to control agricultural and forestry aphids. Although many studies have investigated its biological and ecological characteristics, few molecular studies have been reported. The current study was performed to identify suitable reference genes to facilitate future gene expression and function analyses via quantitative reverse transcription PCR. Eight reference genes glyceraldehyde-3-phosphate dehydrogenase (GAPDH), RPS13, RPL8, RPS3, α-Tub, β-actin, RPL32, and elongation factor 1 alpha (EF1-α) were selected. Their expression levels were determined under four different experimental conditions (developmental stages, adult …

Transiently Impaired Endothelial Function During Thyroid Hormone Withdrawal In Differentiated Thyroid Cancer Patients, Li-Ying Hou, Xiao Li, Guo-Qiang Zhang, Chuang Xi, Chen-Tian Shen, Hong-Jun Song, Wen-Kun Bai, Zhong-Ling Qiu, Quan-Yong Luo

Faculty, Staff and Student Publications

PURPOSE: Endothelial dysfunction, which was associated with chronic hypothyroidism, was an early event in atherosclerosis. Whether short-term hypothyroidism following thyroxine withdrawal during radioiodine (RAI) therapy was associated with endothelial dysfunction in patients with differentiated thyroid cancer (DTC) was unclear. Aim of the study was to assess whether short-term hypothyroidism could impair endothelial function and the accompanied metabolic changes in the whole process of RAI therapy.

METHODS: We recruited fifty-one patients who underwent total thyroidectomy surgery and would accept RAI therapy for DTC. We analyzed thyroid function, endothelial function and serum lipids levels of the patients at three time points: the …

Revisiting The Type Species Of The Genus Homidia (Collembola, Entomobryidae), Guo-Qiang Zhang, Yu-Xin Zhao, Feng Zhang

Faculty, Staff and Student Publications

Homidiacingula Börner, 1906, the type species of the genus Homidia Börner, 1906, is widespread from India to Southeast Asia, but its detailed morphological characteristics have not yet been described. We examined the morphology of specimens of H.cingula from Indonesia and southwestern China and confirmed their conspecific status by comparing their DNA barcoding sequences. We also compared the morphology of H.cingula with other two closely related species, confirming the valid species status of H.subcingula Denis, 1948. Our study provides new taxonomic and molecular data for the genus Homidia.

Minimax Estimation For Personalized Federated Learning: An Alternative Between Fedavg And Local Training?, Shuxiao Chen, Qinqing Zheng, Qi Long, Weijie J Su

Faculty, Staff and Student Publications

A widely recognized difficulty in federated learning arises from the statistical heterogeneity among clients: local datasets often originate from distinct yet not entirely unrelated probability distributions, and personalization is, therefore, necessary to achieve optimal results from each individual's perspective. In this paper, we show how the excess risks of personalized federated learning using a smooth, strongly convex loss depend on data heterogeneity from a minimax point of view, with a focus on the FedAvg algorithm (McMahan et al., 2017) and pure local training (i.e., clients solve empirical risk minimization problems on their local datasets without any communication). Our main result …

Alkyd Resins Produced From Bio-Based Resources For More Sustainable And Environmentally Friendly Coating Applications, Cemi̇l Dizman, Eli̇f Cerrahoğlu Kaçakgi̇l

Turkish Journal of Chemistry

Recently, due to the depletion of natural resources and raising environmental and economic concerns regarding petroleum derivatives, the creation of novel ecologically friendly and sustainable materials made from bio-based and renewable resources is gaining popularity. Alkyd resins are synthetic resins in which both renewable (fatty acids, glycerol, oil, etc.) and nonrenewable (maleic anhydride, pentaerythritol, phthalic anhydride, etc.) raw materials are used in their production. Due to their superior performance (good aging, greater weather resistance and high heat resistance, outstanding gloss, etc.) over other resins, easy application, low cost, and varied use, in the coating and paint industries, they are commonly …

Effect Of Okra Bast Fillers On Biodegradation Properties Of Poly(Vinyl Alcohol) Composites, Gazi Md Arifuzzaman Khan, Nazi̇re Deni̇z Yilmaz

Turkish Journal of Chemistry

This paper focuses on the effect of okra bast fillers on biodegradation of poly(vinyl alcohol) composites. Fibers were obtained from okra plant stems via biological degumming and subjected to different chemical treatments such as scouring, alkalizing, maleic anhydride treatment, and vinyl acetate grafting. The fibers were ground and PVA-okra bast filler composites were produced at 20 wt% fiber load via the solution casting method. The obtained composites were tested in terms of mechanical properties and exposed to biodegradation in soil. Effects of okra bast filler addition and chemical treatments on changes in mass, breaking strength, elasticity modulus, and breaking elongation …

Effect Of Carbon Fiber Reinforcement On Dimensional Variations Of 3d Printed Polyamide-6 Composites: A Simulation Study, Ans Al Rashid, Hamid Ikram, Muammer Koç

Turkish Journal of Chemistry

Due to material design and fabrication flexibility, additive manufacturing (AM) or 3D printing (3DP) processes and polymer composites have paved their way into several industrial sectors. The quality of 3D printed polymer composites is highly dependent on the reinforcement content of polymers and 3DP process parameters. Several experimental studies are performed to optimize the reinforcement contents and process parameters; however, exploring the numerical modeling and simulation techniques is vital to lower the research and development costs. In the study, the numerical simulations for the 3DP process were performed using Digimat® software for carbon fiber-reinforced polyamide-6 (PA6) composites fabricated via the …

Effect Of Calcium Carbonate Particle Size And Content On The Thermal Properties Of Pvc Foamed Layer Used For Coated Textiles, Mouna Stambouli, Walid Chaouch, Sondes Gargoubi, Riadh Zouari, Slah Msahli

Turkish Journal of Chemistry

The goal of this research is to see how the amount and particle size of calcium carbonate (CaCO$_{3}$) used in the foamed layer in use for PVC-coated textiles affects the thermal properties of the material. Two different particle sizes were used at various concentrations. The impact of different CaCO$_{3}$ loadings and particle sizes on the PVC foamed layer's thermal properties were examined. Thermogravimetry (TGA and DTG) and differential scanning calorimetry (DSC) measurements were utilized to investigate the thermal properties of the PVC foamed layer and the samples have been also characterized by FTIR spectroscopy. According to the findings, the thermal …

Electrically Assisted Solution Blow Spinning Of Pvdf/Tpu Nanofibrous Mats For Air Filtration Applications, Andinet Kumella Eticha, Ali̇ Toptaş, Yasi̇n Akgül, Ali̇ Kiliç

Turkish Journal of Chemistry

In this study, pure polyvinylidene fluoride (PVDF), pure thermoplastic polyurethane (TPU), and PVDF/TPU blend nanofibers (1:3, 2:2, 3:1 ratios) were produced via electrically assisted solution blow spinning for air filtration applications. Scanning electron microscopy (SEM) analysis was conducted to investigate the diameters and morphology of nanofibers. The filtration performance of nanofibrous mats was examined by air filtration test with challenging with 0.26 ± 0.07 μm salt particles. Moreover, the flexibility and strength of the samples were determined via tensile tests. Results showed that pure TPU nanofibers had better mechanical properties, while pure PVDF nanofibers showed better filtration performance. However, 3PVDF/1TPU …

Investigating The Effect Of Poly (Ε-Caprolactone) Nanofibers Scaffolds With Random, Unidirectionally, And Radially Aligned Morphologies On The Fibroblast Cell?S Attachment And Growth Behavior, Saeed Nezari, Mohammadamin Sarli, Ahmad Hivechi, Hajir Bahrami, Peiman B. Milan, Noorahmad Latifi, Fatemeh Latifi, Tayyeb Ghadimi, S. Mohammad Amin Haramshahi, Soheila Naderi Gharahgheshlagh

Turkish Journal of Chemistry

In the last decade, significant progress in tissue engineering, repairing, and replacing organs has been achieved. The design and production of scaffolds for tissue engineering are one of the main areas which have attracted the researcher's interest. In this regard, electrospinning is one of the most popular methods of nanoscale scaffold similar to extracellular matrix production. This paper reports the fabrication of scaffolds consisting of radially aligned PCL nanofibers by utilizing a collector composed of a central point electrode and a peripheral ring electrode. The chemical and physical properties were compared using SEM, FTIR, XRD, and DSC experiments, as well …

Surface Modification Of Polypropylene Nonwoven With Chitosan, Tio$_{2}$, And Ag Nanoparticles For The Removal Of Acid Dye From Water, Aminoddin Haji, Mohsen Hadizadeh, Masoumeh Ferdosi

Turkish Journal of Chemistry

In this study, polypropylene nonwoven was coated with chitosan after being activated by oxygen/argon low-pressure plasma. The chitosan-treated sample (PP-Ch) was coated with TiO$_{2}$ nanoparticles by a pad-dry method. Silver nanoparticles were in situ synthesized on the chitosan-TiO$_{2}$-coated sample by a chemical reduction method. The morphology of each of the samples mentioned above was evaluated by FESEM. The efficiency of each sample in the removal of C.I. Acid Brown 248 from aqueous media was evaluated. The PP-Ch sample removed 90% of the dye at pH=3. Coating the PP-Ch sample with TiO$_{2}$ and silver nanoparticles improved the dye removal efficiency under …

Copper-Catalyzed Reactions Of Β-Alkoxy/Phenoxy Enones With Dimethyl Diazomalonate, Füsun Şeyma Kişkan

Turkish Journal of Chemistry

2,3-dihydrofurans were synthesized from carbonyl-ylides via 1,5-electrocyclization reactions with high yields. Dimethyl diazomalonate was reacted with several β-alkoxy and/or β-phenoxy α,β-unsaturated compounds in the presence of Cu(acac)$_{2}$ as a catalyst. From the reaction of β-methoxy enone with diazo compound, dioxole, and Cα-H insertion products were also obtained as side products along with 2,3-dihydrofuran derivative. When the unsaturated compound has an ester and a ketone group, only one dihydrofuran derivative was formed, which occurred by the 1,5-ring closure of keto-carbonyl ylide. Dihydrofuran derivative from the formation of ester carbonyl ylide in the reactions was not obtained.

Removal Of Amoxicillin Via Chromatographic Monolithic Columns: Comparison Between Batch And Continuous Fixed Bed, Mustafa Deni̇z Ağlamaz, Koray Şarkaya, Deni̇z Türkmen, Mustafa Uçar, Adi̇l Deni̇zli̇

Turkish Journal of Chemistry

This study presented a hydrophobic interaction-based poly(HEMA-MATrp) monolithic chromatographic column (MCC) to remove amoxicillin from aqueous solutions. In addition to their porous structure, monolithic-filled columns offer superior properties without loss of performance, which is one of the points that make them unique. The specific surface area of the monolithic column synthesized by the bulk polymerization of 2-hydroxyethyl methacrylate and N-Methacryloyl-L-tryptophan. Also, poly(HEMAMATrp) MCC has been characterized via FTIR, SEM, and elemental analysis. According to BET analysis, the specific surface area of the poly(HEMA-MATrp) monolithic chromatographic column (MCC) is 14.2 mg/g. The adsorption and desorption of amoxicillin in an aqueous solution …

Catalytic Evaluation Of Cellulose Pyrolysis By Using Nanosized Metal Oxide Catalysts, Yusuf Osman Donar, Ali̇ Tolga Ünalan, Samed Ergenekon, Ali̇ Sinağ

Turkish Journal of Chemistry

In this study, effects of TiO$_{2}$ and ZnO nanometal oxides on cellulose pyrolysis have been investigated. Both catalysts have been synthesized via hydrothermal method and characterized by using different techniques. Catalytic and catalyst-free experiments were carried out so as to identify the catalytic abilities of synthesized nanoparticles. Catalyst-free experiments were carried out at 500, 600, and 700 °C in order to determine the optimal condition for pyrolysis and it was found as 700 °C. Optimum catalyst ratio for cellulose pyrolysis was found as 5% (w/w) for both TiO$_{2}$ and ZnO catalysts. GC-MS and micro-GC analyses were conducted in order to …

Evaluation Of Photochemically Cross-Linked Collagen/Gold Nanoparticle Composites As Potential Skin Tissue Scaffolds, Evri̇m Meri̇ç Yelkuvan, Özge Erdemli̇, Bengi̇ Yilmaz, Ömer Aktürk

Turkish Journal of Chemistry

Collagen type I is the main structural unit in skin tissue and is therefore used preferentially in skin tissue scaffolds. However, collagen-based 3D scaffolds have weak aqueous stability and degradation profiles in their uncross-linked states and chemical cross-linking reagents arise toxicity concerns, which generally restrict the spectrum of their biomedical applicability. Here, the research goal is to photochemically cross-link collagen type I with rose bengal (RB) when subjected to green laser light and to investigate the effect of silk sericin-capped gold nanoparticles (S-AuNP) when incorporated into scaffolds on the cross-linking process and thus on the scaffold properties. All the collagen …

Electrochemical Determination Of Aripiprazole Based On Aluminium Oxide Nanoparticles Modified Carbon Paste Electrode, Funda Öztürk, Eli̇f Yüksel, Pinar Esra Erden, Esma Kiliç

Turkish Journal of Chemistry

The electrochemical oxidation of aripiprazole was explored at a carbon paste electrode modified with aluminium oxide nanoparticles by cyclic voltammetry and square-wave anodic adsorptive stripping voltammetry. Experimental parameters such as carbon paste composition, scan rate, buffer pH, accumulation time, and accumulation potential were optimized in order to obtain high analytical performance. The incorporation of aluminium oxide nanoparticles into the carbon paste matrix enhanced the effective surface area of the carbon paste electrode and improved the sensitivity. On the aluminium oxide nanoparticles modified carbon paste electrode, aripiprazole exhibited an irreversible anodic peak at +1.17 V in pH 1.8 BR buffer solution. …

Polymeric Nanoparticle-Based Electrochemical Sensor For The Detection Of Ca 125, Ceren Türkcan, Si̇nan Akgöl

Turkish Journal of Chemistry

In this paper, Cys-graft-p(HEMA) nanomaterials and a new electrochemical method were developed for determination of CA 125. Cys-graft-p(HEMA) nanomaterials were synthesized with emulsion polymerization method and modified with grafting procedure. It was determined that Cys-graft-p(HEMA) nanomaterials had 50 nm dimension and spherical morphology, and per gram polymeric material contained 0.011 mmol L-cysteine. Electrode surface was prepared step by step for electrochemical analysis with optimization process. Linear determination range was determined as 5-400 U/mL (R= 0.9935). Detection limit (LOD) was calculated as 1.87 U/mL, and quantification limit (LOQ) was determined as 5.62 U/mL. The fabricated sensor system showed good repeatability, accuracy, …

Estimation Of The Work Of Adhesion Between Ito And Polymer Substrates: A Surface Thermodynamics Approach, Sali̇h Özbay

Turkish Journal of Chemistry

Indium tin oxide (ITO) is one of the most widely used semiconductor among transparent conducting oxides (TCOs) due to their electrical conductivity and optical transparency properties. Since the development of low temperature deposition methods, coating of ITO on polymer substrates especially for use in flexible electronics has been a popular topic. The existence of adequate adhesion strength between ITO and polymer is critical in producing a successful film. Nowadays, polycarbonate (PC), poly(methyl methacrylate) (PMMA) and polyethyleneterephtalate (PET) are frequently used as substrates for such coatings. However, there may be other polymeric alternatives that have a potential to be used for …

Carbon Quantum Dots And Chitosan-Based Heterogeneous Silver Catalyst For Reduction Of Nitroaromatic Compounds, Farah Sami̇r Sali̇m, İdri̇s Sargin, Gülşi̇n Arslan

Turkish Journal of Chemistry

Chitosan plays a crucial role in catalysis, environmental remediation, and sustainable chemistry as a renewable and cationic polysaccharide. Chitosan-based metal catalysts are used in a broad range of chemical transformations. In the study, carbon quantum dots (CQDs) were derived from Momordica charantia fruits by microwave irradiation following a green chemistry approach. Three catalysts were designed: Ag(0)-chitosan, Ag(0)-chitosan-M. charantia fruit powder, and Ag(0)-chitosan-CQDs. The catalyst supports were prepared by stabilizing CQDs or M. charantia powder within the polymeric matrix of chitosan beads. Metallic silver particles were anchored onto glutaraldehyde cross-linked chitosan beads from the aqueous solution of silver nitrate. The …

Structure-Emission Relationship Of Some Coumarin Laser Dyes And Related Molecules: Prediction Of Radiative Energy Dissipation And The Intersystem Crossing Rate Constants, Msa Abdelmottaleb

Turkish Journal of Chemistry

Dye lasers are commonly used in optical investigation because their solutions in organic solvents deliver tunable, coherent emissions. They exhibit intense fluorescence owing to some specific spectroscopic characteristics. One drawback of the laser dyes is that it shows excessive triplet-state losses (TSLs.) The lack of theoretical predictions of fluorescence rates, intersystem crossing (ISC), and phosphorescence in laser dyes prompted us to report on the predicted rates of radiative and nonradiative transitions of some laser dyes. Structural engineering by some substituents influencing the simulated rates of coumarin laser dye derivatives for an efficient operation was investigated. The NH$_{2}$ functional group renders …

Design, Synthesis, And Enzyme Inhibition Evaluation Of Some Novel Mono- And Di-O-Ss-D-Glycopyranosyl Chalcone Analogues With Molecular Docking Studies, Gonca Çeli̇k, Gi̇zem Tatar Yilmaz, Hüseyi̇n Şahi̇n, Burak Barut, Nuretti̇n Yayli

Turkish Journal of Chemistry

In this study, some novel mono- and di-O-β-D-glycopyranosyl chalcone analogs were designed, synthesized, and characterized. The chalcone derivatives were synthesized with good yields by base-catalyzed Claisen-Schmidt condensation in EtOH solution. Then these chalcones were reacted with TAGBr (2,3,4,6-tetra-O-acetyl-μ-D-glucopyranosylbromide) in dry acetone under the anhydrous condition at 0-5 °C. Deacylated was carried out by the Zemplen's method with NaOCH3 in dry methanol results in substituted chalcone-O-glycosides (mono- and di-O-β-D-glycopyranosyl chalcone analogs). The chemical structures of all synthesized compounds were elucidated based on IR, NMR spectral data, and mass spectrometry. Further, the compounds (7a-c, 8a-c, 12a-c, 16a-c, and 17a-c) …

Synthesis And Kinetic Analysis Of Poly(N-Acryloylmorpholine) Brushes Via Surface Initiated Raft Polymerization, Esma Mutlutürk, Tuncer Çaykara

Turkish Journal of Chemistry

Polymer brushes are promising many applications as smart materials and biocompatible surfaces. Surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization is one of the most effective techniques for synthesis of well-defined polymer brushes. Herein, a biocompatible, uniform and stable poly(N-acryloylmorpholine)-silicon hybrid system was achieved using surface-initiated RAFT polymerization. Evidence of a well-controlled surface-initiated RAFT polymerization was confirmed by a linear increase of number average molecular weight (M$_{n}$) with overall monomer conversions. Water contact angle, ellipsometry, X-ray photoelectron spectroscopy and atomic force microscopy verified the presence of poly(N-acryloylmorpholine) (poly(NAM)) on silicon wafers. The grafting density (σ) and the average distance between grafting …

Fabrication Of Dendritic Pdcu Alloy Supported On 3d N-Doped Hollow Graphene For Efficient Ethanol Electrooxidation, Zhijie Ji̇ang, Shuiyuan Fu, Wei Zhao, Xvtang Liu, Fei Wang, Mingyu Cui, Linyang Dong

Turkish Journal of Chemistry

Fabricating highly efficient Pd-based nanocatalysts with a well-defined structure is desired for the commercialization of direct ethanol fuel cell (DEFC). Herein, a series of hierarchical three-dimensional N-doped hollow graphene spheres (NHGS) supported dendritic PdCu alloy catalysts Pd$_{x}$Cu$_{(d)}$-NHGS (x: Cu/Pd theoretical molar ratio of 4, 2, and 1) are assembled by one-pot ascorbic acid reduction-immobilization method. Aiming to maximize the Pd utilization and realize the efficient ethanol electrooxidation, this novel electrocatalyst offers potent activity sites and promotes electron and ion kinetics simultaneously. Characterization indicates that the as-obtained Pd$_{4}$Cu$_{(d)}$ alloy nanoparticles with average sizes of approximately 55 nm are evenly dispersed on …