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Keywords = CMP residues

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21 pages, 1690 KB  
Article
Hazardous Heritage: From CMP to Hazard-Aware Conservation—A Framework for Polluted Industrial Heritage
by Anna Orchowska and Jakub Szczepański
Sustainability 2026, 18(2), 957; https://doi.org/10.3390/su18020957 - 17 Jan 2026
Viewed by 647
Abstract
Industrial heritage sites hold significant historical and architectural value and their attractive urban locations make them frequent targets for adaptive reuse. Yet decades of industrial activity have left hazardous residues embedded in building fabric, posing risks to public health. Current conservation practice rarely [...] Read more.
Industrial heritage sites hold significant historical and architectural value and their attractive urban locations make them frequent targets for adaptive reuse. Yet decades of industrial activity have left hazardous residues embedded in building fabric, posing risks to public health. Current conservation practice rarely incorporates systematic identification and mapping of such contamination, creating a critical gap that can undermine both safety and the authenticity and integrity of historical material layers. This article proposes an interdisciplinary methodological framework for identifying, analysing, and managing contamination in post-industrial heritage. The model extends the Conservation Management Plan (CMP) by integrating chemical and toxicological analyses, GIS-based diagnostics, and ontological data modelling (CIDOC CRM). It supports value-based decision-making by enabling the safe recognition and preservation of historical layers that may contain toxic residues. The framework is being tested at the former Gdańsk Shipyard through integrated historical research, conservation surveys, and laboratory analyses to assess its applicability and scalability. The proposed approach is intended as a transferable tool for managing polluted heritage environments, aligned with SDGs 11 and 12. Full article
(This article belongs to the Section Tourism, Culture, and Heritage)
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31 pages, 2257 KB  
Article
The Impact and Mechanism of Ecological Assistance on Farmers’ Policy Satisfaction from the Perspective of Peer Effects: Evidence from Designated Assistance Counties of China
by Rong Zhao and Xin Zhao
Land 2026, 15(1), 108; https://doi.org/10.3390/land15010108 - 7 Jan 2026
Viewed by 452
Abstract
Against the backdrop of rising farm household incomes alongside a widening internal income gap in rural China, investigating the impact of peer effects in ecological assistance (PEEA) on farmers’ policy satisfaction is crucial for formulating more targeted support policies and mitigating rural income [...] Read more.
Against the backdrop of rising farm household incomes alongside a widening internal income gap in rural China, investigating the impact of peer effects in ecological assistance (PEEA) on farmers’ policy satisfaction is crucial for formulating more targeted support policies and mitigating rural income inequality. Utilizing 2023 survey data from designated assistance counties of the National Forestry and Grassland Administration (NFGA) of China, this study employs methods such as Oprobit and moderation effects to examine the factors and mechanisms through which peer effects in ecological assistance affect farmers’ policy satisfaction. The results indicate that PEEA exert a negative influence on farmers’ policy satisfaction, a finding that remains robust after endogeneity checks using the conditional mixed process (CMP) model and residual analysis. The information transmission mechanism can strengthen the suppressive effect of these peer effects on satisfaction, whereas the social interaction mechanism exhibits a substitution effect with the peer effects. The peer effects are asymmetric, with a more pronounced negative impact on policy satisfaction among farmers over 50 years old and those with lower human capital. Furthermore, the peer effect is most significant for forestry property income, followed by forestry wage income and forestry operating income. Farmer groups with low-to-medium forestry income are more significantly affected by PEEA. Furthermore, among these, the medium forestry income cohort demonstrates the highest sensitivity to the influence of PEEA on policy satisfaction. Therefore, ecological assistance policies should be further optimized, and forestry income should be distributed equitably to enhance the sense of policy benefit and well-being among farmers. Meanwhile, information channels should be improved to guide rational interpersonal expenditure, target groups with strong peer demonstration effects, explore diversified forestry management projects, and broaden income-increasing channels through ecological assistance. Full article
(This article belongs to the Section Land Socio-Economic and Political Issues)
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18 pages, 2565 KB  
Article
Agronomic and Physicochemical Quality of Broccoli Cultivated Under Different Fertilizers and Phosphorus Rates
by Dinamar Márcia da Silva Vieira, Reginaldo de Camargo, Miguel Henrique Rosa Franco, Valdeci Orioli Júnior, Cintia Cristina de Oliveira, Arcângelo Loss, Fausto Antônio Domingos Júnior, Maytê Maria Abreu Pires de Melo Silva and José Luiz Rodrigues Torres
Horticulturae 2025, 11(8), 873; https://doi.org/10.3390/horticulturae11080873 - 25 Jul 2025
Viewed by 1381
Abstract
The aim of this study was to evaluate the agronomic performance and physicochemical characteristics of broccoli grown under different doses and sources of special phosphorus (P) fertilizers and their residual effect on the soil, in Cerrado mineiro. A randomized block design arranged in [...] Read more.
The aim of this study was to evaluate the agronomic performance and physicochemical characteristics of broccoli grown under different doses and sources of special phosphorus (P) fertilizers and their residual effect on the soil, in Cerrado mineiro. A randomized block design arranged in a split-plot scheme was employed, where three P sources—T1 = Conventional monoammonium phosphate (CMP); T2 = Polymerized monoammonium phosphate (PCMP); T3 = Granulated organomineral fertilizer (GOF)—along with four P2O5 rates—1–0 (No P); 2–50% (200 kg ha−1 P2O5); 3–75% (300 kg ha−1 P2O5); and 4–100% (400 kg ha−1 P2O5)—were assessed. Evaluations included the number of leaves (NL), head fresh (HFM) and dry mass (HDM), yield (YLD), soil fertility at harvest, plant nutritional status, and the physicochemical quality of the harvested broccoli. It was observed that GOF provided the best agronomic performance (HFM, HDM and YLD) of the broccoli and the greatest residual effect in the soil compared to PCMP and CMP. The moisture, ash, protein, lipid, total titratable acid and ascorbic acid contents were not significantly (p < 0.05) affected by the fertilizers used, on the other hand, total soluble solids and hydrogen potential showed the highest and lowest values, respectively, with CMP. The best agronomic performance, the highest phosphorus content in the soil and plant and the best physical–chemical quality of the broccoli occurred at a dose of 100% (400 kg ha−1 of P2O5) of the recommendation for the crop in all three fertilizers evaluated. Full article
(This article belongs to the Section Plant Nutrition)
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37 pages, 4353 KB  
Article
Tribo-Electrochemical Characterization of Brush-Scrubbed Post-CMP Cleaning: Results for Tartrate-Supported Removal of Residual Oxides from Copper Films
by Collin M. Reff, Kassapa U. Gamagedara, David R. Santefort and Dipankar Roy
Lubricants 2025, 13(7), 301; https://doi.org/10.3390/lubricants13070301 - 8 Jul 2025
Cited by 2 | Viewed by 3298
Abstract
Wafer cleaning after chemical mechanical planarization (CMP) is a critical processing step for copper metallization in integrated circuits. Post-CMP cleaning (PCMPC) commonly combines surface (electro)chemistry with the tribology of brush scrubbing to remove CMP residues from wafer surfaces. While the complex mechanisms of [...] Read more.
Wafer cleaning after chemical mechanical planarization (CMP) is a critical processing step for copper metallization in integrated circuits. Post-CMP cleaning (PCMPC) commonly combines surface (electro)chemistry with the tribology of brush scrubbing to remove CMP residues from wafer surfaces. While the complex mechanisms of brush-operated PCMPC are supported by this combination, the conventional electroanalytical methods of assessing PCMPC efficiency are typically operated in the absence of surface brushing. Using a model experimental system with tartaric acid (TA) as a cost-effective cleaner of Cu-oxides, we illustrate here how post-CMP Cu samples can be electrochemically examined using brush cleaning to design/assess PCMPC test solutions. A pH-neutral cleaning solution is employed, where TA also serves as a partial dissolution suppressor of Cu, and CMP-treated wafer samples are scrubbed with a commercial PCMPC brush as sample surfaces are simultaneously probed with electrochemical measurements. The results show the active roles of tribology/lubrication and surface chemistry in the removal of CMP residues. The electrochemically determined residue removal efficiencies of PCMPC are found to be ~97% and ~56% in the presence and in the absence of surface brushing, respectively. The implications of these findings are explored in the general context of evaluating PCMPC formulations. Full article
(This article belongs to the Special Issue Advances in Tribochemistry)
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18 pages, 1346 KB  
Article
Broccoli Cultivation Under Different Sources and Rates of Specialty Phosphorus Fertilizers in the Brazilian Cerrado
by Dinamar Márcia da Silva Vieira, Reginaldo de Camargo, Miguel Henrique Rosa Franco, Valdeci Orioli Júnior, Arcângelo Loss, Hamilton César de Oliveira Charlo, Fausto Antônio Domingos Júnior and José Luiz Rodrigues Torres
Horticulturae 2025, 11(6), 631; https://doi.org/10.3390/horticulturae11060631 - 4 Jun 2025
Cited by 2 | Viewed by 2152
Abstract
This study aimed to evaluate the agronomic performance and yield of broccoli grown under different sources and rates of specialty phosphorus (P) fertilizers in Uberaba, Minas Gerais, Brazil. The experiment was conducted in a randomized block design arranged in a split-plot scheme, testing [...] Read more.
This study aimed to evaluate the agronomic performance and yield of broccoli grown under different sources and rates of specialty phosphorus (P) fertilizers in Uberaba, Minas Gerais, Brazil. The experiment was conducted in a randomized block design arranged in a split-plot scheme, testing three P sources: (1) conventional monoammonium phosphate (CMP); (2) polymer-coated monoammonium phosphate (PCMP); and (3) organomineral fertilizer (Org). Four application rates were evaluated: 0 (no P applied), 50% (200 kg ha−1 of P2O5), 75% (300 kg ha−1 of P2O5), and 100% (400 kg ha−1 of P2O5) of the recommended phosphorus rate for broccoli, with four replications. The parameters assessed included plant nutritional status, soil fertility at harvest, number of leaves (NL), fresh head weight (FHW), dry head weight (DHW), and broccoli yield (YLD). In the first growing cycle, broccoli showed the highest NL (24), FHW (1.05 kg plant−1), DHW (0.27 kg plant−1), and YLD (18.81 Mg ha−1) values when PCMP was applied, which was 5, 25, 8 and 23% higher than Org and 20, 25, 14 and 34% higher than CMP. In the second cycle, broccoli showed higher values of NL (23), FHW (1.85 kg plant−1), DHW (0.26 kg plant−1), and YLD (33.01 Mg ha−1) where Org was applied, which was 4, 15, 8 and 5% higher than CMP and 2, 24, 4 and 14% higher than PCMP, respectively. All the variables evaluated showed the highest values at the 100% dose. Broccoli yield in the same area was 124%, 153%, and 115% higher in the second cycle compared to the first for CMP, PCMP, and Org, respectively. The greatest residual effect on soil fertility was observed in the area treated with the Org. Full article
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17 pages, 1551 KB  
Article
Bioavailable and Bioaccessible Fractions of Potentially Toxic Elements in Copper Mining Wastes in the Southeastern Amazon
by Gabriela Vilhena de Almeida Pereira, Wendel Valter da Silveira Pereira, Sílvio Junio Ramos, José Tasso Felix Guimarães, Watilla Pereira Covre, Yan Nunes Dias and Antonio Rodrigues Fernandes
Minerals 2025, 15(2), 140; https://doi.org/10.3390/min15020140 - 30 Jan 2025
Cited by 5 | Viewed by 2852
Abstract
The Brazilian Amazon presents several artisanal and industrial Cu mines that generate significant amounts of waste. The objective of this study was to evaluate the risks to the environment and human health based on the bioavailable and bioaccessible concentrations of potentially toxic elements [...] Read more.
The Brazilian Amazon presents several artisanal and industrial Cu mines that generate significant amounts of waste. The objective of this study was to evaluate the risks to the environment and human health based on the bioavailable and bioaccessible concentrations of potentially toxic elements (PTEs; Ba, Co, Cr, Cu, Mo, Ni, Pb, and Zn) in artisanal and industrial Cu mining areas in the Carajás Mineral Province (CMP), eastern Amazon. For this purpose, samples (0–20 cm depth) were collected from natural forest soils (considered as a reference), as well as areas where artisanal mining wastes (artisanal overburden–AO and artisanal rock waste–AR) and industrial mining tailings (IT) were deposited. Total PTE concentrations were obtained via acid digestion, bioavailable concentrations were obtained via sequential extraction, and oral bioaccessible concentrations were obtained via the simple bioaccessibility extraction test. Environmental indices were obtained from PTE concentrations. The results indicated contamination by elements such as Mo, Cr, Ni, and Cu, mainly in AR, which had the highest contamination levels. Sequential extraction revealed that most PTEs are in residual form, suggesting low environmental risk from the bioavailable fraction. The bioaccessible concentrations of Cr and Ni were associated with health risks for children in AR. The results of this study will be important for protecting the environment and public health in artisanal mining areas in the region. Full article
(This article belongs to the Section Environmental Mineralogy and Biogeochemistry)
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12 pages, 3643 KB  
Article
The Enhancing Effect of Biochar Derived from Biogas Residues on the Anaerobic Digestion Process of Pig Manure Water
by Zhanjiang Pei, Xiao Wei, Shiguang Jin, Fengmei Shi, Jie Liu, Su Wang, Pengfei Li, Yifei Luo, Yongkang Wang, Tengfei Wang, Zenghui Ma, Yinxue Li and Yanling Yu
Fermentation 2024, 10(12), 644; https://doi.org/10.3390/fermentation10120644 - 15 Dec 2024
Cited by 2 | Viewed by 2491
Abstract
Biochar-based additives can enhance the ability to produce methane during anaerobic digestion (AD), and biogas residues (BRs) are solid waste that can cause environmental pollution. Therefore, in this work, BRs were used as raw material to prepare biochar, and Fe3+ was used [...] Read more.
Biochar-based additives can enhance the ability to produce methane during anaerobic digestion (AD), and biogas residues (BRs) are solid waste that can cause environmental pollution. Therefore, in this work, BRs were used as raw material to prepare biochar, and Fe3+ was used to modify biochar for use in the AD process, generating pig manure water (PMW). The results showed that biogas residue biochar (BRB) showed good pore size and had a “honeycomb structure” on its surface. The commercially available iron–carbon composite material (Fe-C) showed the greatest cumulative methane production (CMP), the greatest removal rates of chemical oxygen demand (COD), and the greatest degradation rate of volatile fatty acids (VFAs), with the order of Fe-C > Fe3+-modified biogas residue biochar (FBRB) > BRB > control group. Fe3+ and Fe0 showed similar effects, where both could enhance the methanogenesis performance of anaerobic digestion by promoting direct interspecific electron transfer, and Fe0 was slightly more effective than Fe3+. Bacteroidotas and Firmicutes were the predominant phyla, and Clostridium_sensu_stricto_1 was the predominant genus. The addition of biochar and Fe3+ promoted the transformation of microorganisms from the conventional metabolic mode into an efficient metabolic mode. Extracellular electron transfer played a crucial role in this. Full article
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10 pages, 3487 KB  
Article
Detachment Energy Evaluation in Nano-Particle Cleaning Using Lateral Force Microscopy
by Yutaka Terayama, Panart Khajornrungruang, Jihoon Seo, Satomi Hamada, Yutaka Wada and Hirokuni Hiyama
Appl. Sci. 2024, 14(18), 8145; https://doi.org/10.3390/app14188145 - 10 Sep 2024
Cited by 1 | Viewed by 2953
Abstract
It has been difficult to detach abrasive particles smaller than 50 nm from polished surfaces in post-CMP cleaning. During the cleaning process, the residual nano-particles exert shear force in the inevitable shear flow. In order to understand the cleaning mechanism, it is indispensable [...] Read more.
It has been difficult to detach abrasive particles smaller than 50 nm from polished surfaces in post-CMP cleaning. During the cleaning process, the residual nano-particles exert shear force in the inevitable shear flow. In order to understand the cleaning mechanism, it is indispensable to investigate not only the force but also the energy acting on different-sized nano-particles. In this article, we proposed the evaluation of detachment energy (the energy required to detach nano-particles) by using Lateral Force Microscopy. As an example, the dominant detachment energy of the silica nano-particle between the oxide film is the potential energy of the hydrogen bond. It suggested that the silica nano-particle detachment involves the breaking of hydrogen bonds. Full article
(This article belongs to the Section Nanotechnology and Applied Nanosciences)
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13 pages, 4276 KB  
Article
Endpoint Detection Based on Optical Method in Chemical Mechanical Polishing
by Fangxin Tian, Tongqing Wang and Xinchun Lu
Micromachines 2023, 14(11), 2053; https://doi.org/10.3390/mi14112053 - 2 Nov 2023
Cited by 7 | Viewed by 5747
Abstract
Endpoint detection is an important technology in chemical mechanical polishing (CMP), which is used to capture the material interface and compensate the variations of consumables and incoming wafer thickness. This paper aimed to apply optical detection in metal CMP. An in situ optical [...] Read more.
Endpoint detection is an important technology in chemical mechanical polishing (CMP), which is used to capture the material interface and compensate the variations of consumables and incoming wafer thickness. This paper aimed to apply optical detection in metal CMP. An in situ optical measurement system was developed for a 12-inch CMP tool. Kinematic analysis of the scanning trajectory of the laser device indicated the relative position relationship between the device and the wafer. Average optical data within the wafer described the material removal of metal CMP. Furthermore, optical data and location described the non-uniformity of the entire wafer surface. In this research, the polishing condition and the residual of the wafer edge are characterized by optical trace. Pauta Criterion is used to discriminate the inflexion point of the material interface. The results reveal that the interface capture is accurate and effective. Full article
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20 pages, 4201 KB  
Article
Separation and Characterization of Plastic Waste Packaging Contaminated with Food Residues
by Svetlana Tretsiakova-McNally, Helen Lubarsky, Ashlene Vennard, Paul Cairns, Charlie Farrell, Paul Joseph, Malavika Arun, Ian Harvey, John Harrison and Ali Nadjai
Polymers 2023, 15(13), 2943; https://doi.org/10.3390/polym15132943 - 4 Jul 2023
Cited by 7 | Viewed by 4529
Abstract
In this paper, we present the development of a novel processing technology to tackle hard-to-recycle plastic packaging waste contaminated with food residues. The proof-of-concept (POC) technology can effectively separate food residual amounts from plastic waste materials to a level acceptable for further re-use [...] Read more.
In this paper, we present the development of a novel processing technology to tackle hard-to-recycle plastic packaging waste contaminated with food residues. The proof-of-concept (POC) technology can effectively separate food residual amounts from plastic waste materials to a level acceptable for further re-use or recycling of the plastic packaging. To assess this technology, we have conducted spectroscopic, thermal, and calorimetric characterizations of the obtained fractions, such as cleaned mixed plastics (CMP), food waste with mixed plastics (FWMP), and a mixture of microplastics (MP). The analyses were carried out with the aid of Fourier-Transform Infrared spectroscopy (FT-IR), Thermo-Gravimetric Analysis (TGA), Microcone Combustion Calorimetry (MCC), and ‘bomb’ calorimetry. The highest ratio of CMP to FWMP and the lowest amount of MP were obtained utilizing 700 rpm blade rotational speed and 15 s residence time of contaminated plastics in a cutting mill chamber. The plastics were freed from food contamination by 93–97%, which highlights a strong potential of the POC as a solution for ‘dry-cleaning’ of similar wastes on a larger scale. The main components of the CMP fraction were low-density polyethylene (LDPE), polypropylene (PP), and polyethylene terephthalate (PET), which are recyclable plastics. The knowledge and understanding of thermal degradation behaviours and calorimetric attributes of separated fractions, determined in this study, are essential in informing the industrial players using pyrolysis as a technique for recycling plastics. Full article
(This article belongs to the Special Issue Decarbonization of Plastics)
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16 pages, 1446 KB  
Article
A Specific HPLC Method to Determine Residual HEPES in [68Ga]Ga-Radiopharmaceuticals: Development and Validation
by Silvia Migliari, Maura Scarlattei, Giorgio Baldari, Claudia Silva and Livia Ruffini
Molecules 2022, 27(14), 4477; https://doi.org/10.3390/molecules27144477 - 13 Jul 2022
Cited by 13 | Viewed by 3648
Abstract
Background: Nowadays, in Nuclear Medicine, clinically applied radiopharmaceuticals must meet quality release criteria such as high radiochemical purity and radiochemical yield. Many radiopharmaceuticals do not have marketing authorization and have no dedicated monograph within European Pharmacopeia (Ph. Eur.); therefore, general monographs on quality [...] Read more.
Background: Nowadays, in Nuclear Medicine, clinically applied radiopharmaceuticals must meet quality release criteria such as high radiochemical purity and radiochemical yield. Many radiopharmaceuticals do not have marketing authorization and have no dedicated monograph within European Pharmacopeia (Ph. Eur.); therefore, general monographs on quality controls (QCs) have to be applied for clinical application. These criteria require standardization and validation in labeling and preparation, including quality controls measurements, according to well defined standard operation procedures. However, QC measurements are often based on detection techniques that are specific to a certain chromatographic system. Several radiosyntheses of [68Ga]Ga-radiopharmaceuticals are more efficient and robust when they are performed with 2-[4-(2-hydroxyethyl)piperazin-1-yl] ethanesulfonic acid (HEPES) buffer, which is considered as an impurity to be assessed in the QC procedure, prior to clinical use. Thus, Ph. Eur. has introduced a thin-layer chromatography (TLC) method to quantify the HEPES amount that is present in [68Ga]Ga-radiopharmaceuticals. However, this is only qualitative and has proven to be unreliable. Here we develop and validate a new high-performance liquid chromatography (UV-Radio-HPLC) method to quantify the residual amount of HEPES in 68Ga-based radiopharmaceuticals. Method: To validate the proposed UV-Radio-HPLC method, a stepwise approach was used, as defined in the guidance document that was adopted by the European Medicines Agency (CMP/ICH/381/95 2014). The assessed parameters are specificity, linearity, precision (repeatability), accuracy, and limit of quantification. A range of concentrations of HEPES (100, 80, 60, 40, 20, 10, 5, 3 μg/mL) were analyzed. Moreover, to test the validity and pertinence of our new HPLC method, we analyzed samples of [68Ga]Ga-DOTATOC; [68Ga]Ga-PSMA; [68Ga]Ga-DOTATATE; [68Ga]Ga-Pentixafor; and [68Ga]Ga-NODAGA-Exendin-4 from different batches that were prepared for clinical use. Results: In the assessed samples, HEPES could not be detected by the TLC method that was described in Ph. Eur. within 4 min incubation in an iodine-saturated chamber. Our developed HPLC method showed excellent linearity between 3 and 100 μg/mL for HEPES, with a correlation coefficient (R2) for calibration curves that was equal to 0.999, coefficients of variation (CV%) < 2%, and percent deviation value of bias from 100% to 5%, in accordance with acceptance criteria. The intra-day and inter-day precision of our method was statistically confirmed and the limit-of-quantification (LOQ) was 3 μg/mL, confirming the high sensitivity of the method. The amount of HEPES that was detected with our developed HPLC method in the tested [68Ga]Ga-radiopharmaceuticals resulted well below the Ph. Eur. limit, especially for [68Ga]Ga-NODAGA-Exendin-4. Conclusions: The TLC method that is described in Ph. Eur. to assess residual HEPES in [68Ga]-based radiopharmaceuticals may not be sufficiently sensitive and thus unsuitable for QC release. Our new HPLC method was sensitive, quantitative, reproducible, and rapid for QCs, allowing us to exactly determine the residual HEPES amount in [68Ga]Ga-radiopharmaceuticals for safe patient administration. Full article
(This article belongs to the Section Applied Chemistry)
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12 pages, 4573 KB  
Article
Study on Improving the Precise Machinability of Single Crystal SiC by an Ultrasonic-Assisted Hybrid Process
by Dong Shi, Tianchen Zhao, Tengfei Ma and Jinping Pan
Materials 2021, 14(23), 7320; https://doi.org/10.3390/ma14237320 - 30 Nov 2021
Cited by 10 | Viewed by 3683
Abstract
Silicon carbide (SiC) devices have become one of the key research directions in the field of power electronics. However, due to the limitation of the SiC wafer growth process and processing capacity, SiC devices, such as SiC MOSFET (Metal-oxide-semiconductor Field-effect Transistor), are facing [...] Read more.
Silicon carbide (SiC) devices have become one of the key research directions in the field of power electronics. However, due to the limitation of the SiC wafer growth process and processing capacity, SiC devices, such as SiC MOSFET (Metal-oxide-semiconductor Field-effect Transistor), are facing the problems of high cost and unsatisfied performance. To improve the precise machinability of single-crystal SiC wafer, this paper proposed a new hybrid process. Firstly, we developed an ultrasonic vibration-assisted device, by which ultrasonic-assisted lapping and ultrasonic-assisted CMP (chemical mechanical polishing) for SiC wafer were fulfilled. Secondly, a novel three-step ultrasonic-assisted precise machining route was proposed. In the first step, ultrasonic lapping using a cast iron disc was conducted, which quickly removed large surface damages with a high MRR (material removal rate) of 10.93 μm/min. In the second step, ultrasonic lapping using a copper disc was conducted, which reduced the residual surface defects with a high MRR of 6.11 μm/min. In the third step, ultrasonic CMP using a polyurethane pad was conducted, which achieved a smooth and less damaged surface with an MRR of 1.44 μm/h. These results suggest that the ultrasonic-assisted hybrid process can improve the precise machinability of SiC, which will hopefully achieve high-efficiency and ultra-precision machining. Full article
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18 pages, 2863 KB  
Article
Processing and Bypass of a Site-Specific DNA Adduct of the Cytotoxic Platinum–Acridinylthiourea Conjugate by Polymerases Involved in DNA Repair: Biochemical and Thermodynamic Aspects
by Monika Hreusova, Viktor Brabec and Olga Novakova
Int. J. Mol. Sci. 2021, 22(19), 10838; https://doi.org/10.3390/ijms221910838 - 7 Oct 2021
Cited by 2 | Viewed by 3246
Abstract
DNA-dependent DNA and RNA polymerases are important modulators of biological functions such as replication, transcription, recombination, or repair. In this work performed in cell-free media, we studied the ability of selected DNA polymerases to overcome a monofunctional adduct of the cytotoxic/antitumor platinum–acridinylthiourea conjugate [...] Read more.
DNA-dependent DNA and RNA polymerases are important modulators of biological functions such as replication, transcription, recombination, or repair. In this work performed in cell-free media, we studied the ability of selected DNA polymerases to overcome a monofunctional adduct of the cytotoxic/antitumor platinum–acridinylthiourea conjugate [PtCl(en)(L)](NO3)2 (en = ethane-1,2-diamine, L = 1-[2-(acridin-9-ylamino)ethyl]-1,3-dimethylthiourea) (ACR) in its favored 5′-CG sequence. We focused on how a single site-specific ACR adduct with intercalation potency affects the processivity and fidelity of DNA-dependent DNA polymerases involved in translesion synthesis (TLS) and repair. The ability of the G(N7) hybrid ACR adduct formed in the 5′-TCGT sequence of a 24-mer DNA template to inhibit the synthesis of a complementary DNA strand by the exonuclease-deficient Klenow fragment of DNA polymerase I (KFexo−) and human polymerases eta, kappa, and iota was supplemented by thermodynamic analysis of the polymerization process. Thermodynamic parameters of a simulated translesion synthesis across the ACR adduct were obtained by using microscale thermophoresis (MST). Our results show a strong inhibitory effect of an ACR adduct on enzymatic TLS: there was only small synthesis of a full-length product (less than 10%) except polymerase eta (~20%). Polymerase eta was able to most efficiently bypass the ACR hybrid adduct. Incorporation of a correct dCMP opposite the modified G residue is preferred by all the four polymerases tested. On the other hand, the frequency of misinsertions increased. The relative efficiency of misinsertions is higher than that of matched cytidine monophosphate but still lower than for the nonmodified control duplex. Thermodynamic inspection of the simulated TLS revealed a significant stabilization of successively extended primer/template duplexes containing an ACR adduct. Moreover, no significant decrease of dissociation enthalpy change behind the position of the modification can contribute to the enzymatic TLS observed with the DNA-dependent, repair-involved polymerases. This TLS could lead to a higher tolerance of cancer cells to the ACR conjugate compared to its enhanced analog, where thiourea is replaced by an amidine group: [PtCl(en)(L)](NO3)2 (complex AMD, en = ethane-1,2-diamine, L = N-[2-(acridin-9-ylamino)ethyl]-N-methylpropionamidine). Full article
(This article belongs to the Special Issue 25th Anniversary of IJMS: Advances in Biochemistry)
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14 pages, 2476 KB  
Article
Knockout of the CMP–Sialic Acid Transporter SLC35A1 in Human Cell Lines Increases Transduction Efficiency of Adeno-Associated Virus 9: Implications for Gene Therapy Potency Assays
by Antje Banning, Anna Zakrzewicz, Xin Chen, Steven J. Gray and Ritva Tikkanen
Cells 2021, 10(5), 1259; https://doi.org/10.3390/cells10051259 - 19 May 2021
Cited by 15 | Viewed by 7266
Abstract
Recombinant adeno-associated viruses (AAV) have emerged as an important tool for gene therapy for human diseases. A prerequisite for clinical approval is an in vitro potency assay that can measure the transduction efficiency of each virus lot produced. The AAV serotypes are typical [...] Read more.
Recombinant adeno-associated viruses (AAV) have emerged as an important tool for gene therapy for human diseases. A prerequisite for clinical approval is an in vitro potency assay that can measure the transduction efficiency of each virus lot produced. The AAV serotypes are typical for gene therapy bind to different cell surface structures. The binding of AAV9 on the surface is mediated by terminal galactose residues present in the asparagine-linked carbohydrates in glycoproteins. However, such terminal galactose residues are rare in cultured cells. They are masked by sialic acid residues, which is an obstacle for the infection of many cell lines with AAV9 and the respective potency assays. The sialic acid residues can be removed by enzymatic digestion or chemical treatment. Still, such treatments are not practical for AAV9 potency assays since they may be difficult to standardize. In this study, we generated human cell lines (HEK293T and HeLa) that become permissive for AAV9 transduction after a knockout of the CMP–sialic acid transporter SLC35A1. Using the human aspartylglucosaminidase (AGA) gene, we show that these cell lines can be used as a model system for establishing potency assays for AAV9-based gene therapy approaches for human diseases. Full article
(This article belongs to the Special Issue Lysosomal Storage Disorders)
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29 pages, 9605 KB  
Article
Advanced Spectroscopy and APBS Modeling for Determination of the Role of His190 and Trp103 in Mouse Thymidylate Synthase Interaction with Selected dUMP Analogues
by Małgorzata Prokopowicz, Adam Jarmuła, Yannick Casamayou-Boucau, Fiona Gordon, Alan Ryder, Justyna Sobich, Piotr Maj, Joanna Cieśla, Zbigniew Zieliński, Piotr Fita and Wojciech Rode
Int. J. Mol. Sci. 2021, 22(5), 2661; https://doi.org/10.3390/ijms22052661 - 6 Mar 2021
Cited by 1 | Viewed by 6341
Abstract
A homo-dimeric enzyme, thymidylate synthase (TS), has been a long-standing molecular target in chemotherapy. To further elucidate properties and interactions with ligands of wild-type mouse thymidylate synthase (mTS) and its two single mutants, H190A and W103G, spectroscopic and theoretical investigations have been employed. [...] Read more.
A homo-dimeric enzyme, thymidylate synthase (TS), has been a long-standing molecular target in chemotherapy. To further elucidate properties and interactions with ligands of wild-type mouse thymidylate synthase (mTS) and its two single mutants, H190A and W103G, spectroscopic and theoretical investigations have been employed. In these mutants, histidine at position 190 and tryptophan at position 103 are substituted with alanine and glycine, respectively. Several emission-based spectroscopy methods used in the paper demonstrate an especially important role for Trp 103 in TS ligands binding. In addition, the Advanced Poisson–Boltzmann Solver (APBS) results show considerable differences in the distribution of electrostatic potential around Trp 103, as compared to distributions observed for all remaining Trp residues in the mTS family of structures. Together, spectroscopic and APBS results reveal a possible interplay between Trp 103 and His190, which contributes to a reduction in enzymatic activity in the case of H190A mutation. Comparison of electrostatic potential for mTS complexes, and their mutants, with the substrate, dUMP, and inhibitors, FdUMP and N4-OH-dCMP, suggests its weaker influence on the enzyme–ligand interactions in N4OH-dCMP-mTS compared to dUMP-mTS and FdUMP-mTS complexes. This difference may be crucial for the explanation of the ”abortive reaction” inhibitory mechanism of N4OH-dCMP towards TS. In addition, based on structural analyses and the H190A mutant capacity to form a denaturation-resistant complex with N4-OH-dCMP in the mTHF-dependent reaction, His190 is apparently responsible for a strong preference of the enzyme active center for the anti rotamer of the imino inhibitor form. Full article
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