Now showing items 1-20 of 53388

    • Expansion Planning for Renewable Integration in Power System of Regions with Very High Solar Irradiation

      Alraddadi, Musfer; Conejo, Antonio J.; Lima, Ricardo (Journal of Modern Power Systems and Clean Energy, Journal of Modern Power Systems and Clean Energy, 2021-09-15) [Article]
      In this paper, we address the long-term generation and transmission expansion planning for power systems of regions with very high solar irradiation. We target the power systems that currently rely mainly on thermal generators and that aim to adopt high shares of renewable sources. We propose a stochastic programming model with expansion alternatives including transmission lines, solar power plants (photovoltaic and concentrated solar), wind farms, energy storage, and flexible combined cycle gas turbines. The model represents the longterm uncertainty to characterize the demand growth, and the short-term uncertainty to characterize daily solar, wind, and demand patterns. We use the Saudi Arabian power system to illustrate the functioning of the proposed model for several cases with different renewable integration targets. The results show that a strong dependence on solar power for high shares of renewable sources requires high generation capacity and storage to meet the night demand.
    • Influence of the anionic ligands on properties and reactivity of Hoveyda-Grubbs catalysts

      Albalawi, Mona O.; Falivene, Laura; Jedidi, Abdesslem; Osman, Osman I.; Elroby, Shaaban A.; Cavallo, Luigi (Molecular Catalysis, Elsevier BV, 2021-06-26) [Article]
      Ruthenium based catalysts remain among the more successful complexes used in the catalysis of metathesis processes for the synthesis of new carbon-carbon bonds. The investigation of the influence of the different system moieties on its catalytic performance has led to important improvements in the field. To this extent, density functional theory (DFT) calculations have contributed significantly providing fundamental understandings to develop new catalysts. With this aim, we presented here a detailed computational study of how the nature of the anion ligand binding to the metal affects the global properties and reactivity of the catalyst. Geometric, energetic and electronic analysis have been performed to reach the key insights necessary to build structure-performance correlations.
    • A Corrected Cubic Law for Single-phase Laminar Flow through Rough-walled Fractures

      He, Xupeng; Sinan, Marwa; Kwak, Hyung; Hoteit, Hussein (Advances in Water Resources, Elsevier BV, 2021-06-19) [Article]
      Hydraulic properties of natural fractures are essential parameters for the modeling of fluid flow and transport in subsurface fractured porous media. The cubic law, based on the parallel-plate concept, has been traditionally used to estimate the hydraulic properties of individual fractures. This upscaling approach, however, is known to overestimate the fractures hydraulic properties. Dozens of methods have been proposed in the literature to improve the accuracy of the cubic law. The relative performance of these various methods is not well understood. In this work, a comprehensive review and benchmark of almost all commonly used cubic law-based approaches in the literature, covering 43 methods is provided. We propose a new corrected cubic law for incompressible, single-phase laminar flow through rough-walled fractures. The proposed model incorporates corrections to the hydraulic fracture aperture based on the flow tortuosity and local roughness of the fracture walls. We identify geometric rules relative to the local characteristic of the fracture and apply an efficient algorithm to subdivide the fracture into segments, accordingly. High-resolution simulations for Navier-Stokes equations, computed in parallel, for synthetic fractures with various ranges of surface roughness and apertures are then performed. The numerical solutions are used to assess the accuracy of the proposed model and compare it with the other 43 approaches, where we demonstrate its superior accuracy. The proposed model retains the simplicity and efficiency of the cubic law but with pronounced improvement to its accuracy. The data set used in the benchmark, including more than 7500 fractures, is provided in open-access.
    • Protein phosphatase 1 regulates atypical mitotic and meiotic division in Plasmodium sexual stages

      Zeeshan, Mohammad; Pandey, Rajan; Subudhi, Amit; Ferguson, David J P; Kaur, Gursimran; Rashpa, Ravish; Nugmanova, Raushan; Brady, Declan; Bottrill, Andrew R.; Vaughan, Sue; Brochet, Mathieu; Bollen, Mathieu; Pain, Arnab; Holder, Anthony A.; Guttery, David S.; Tewari, Rita (Communications Biology, Springer Science and Business Media LLC, 2021-06-18) [Article]
      AbstractPP1 is a conserved eukaryotic serine/threonine phosphatase that regulates many aspects of mitosis and meiosis, often working in concert with other phosphatases, such as CDC14 and CDC25. The proliferative stages of the malaria parasite life cycle include sexual development within the mosquito vector, with male gamete formation characterized by an atypical rapid mitosis, consisting of three rounds of DNA synthesis, successive spindle formation with clustered kinetochores, and a meiotic stage during zygote to ookinete development following fertilization. It is unclear how PP1 is involved in these unusual processes. Using real-time live-cell and ultrastructural imaging, conditional gene knockdown, RNA-seq and proteomic approaches, we show that Plasmodium PP1 is implicated in both mitotic exit and, potentially, establishing cell polarity during zygote development in the mosquito midgut, suggesting that small molecule inhibitors of PP1 should be explored for blocking parasite transmission.
    • Delivery of Endothelial Cell-Laden Microgel Elicits Angiogenesis in Self-Assembling Ultrashort Peptide Hydrogels In Vitro

      Ramirez Calderon, Gustavo; Susapto, Hepi Hari; Hauser, Charlotte (ACS Applied Materials & Interfaces, American Chemical Society (ACS), 2021-06-18) [Article]
      Blood vessel generation is an essential process for tissue formation, regeneration, and repair. Notwithstanding, vascularized tissue fabrication in vitro remains a challenge, as current fabrication techniques and biomaterials lack translational potential in medicine. Naturally derived biomaterials harbor the risk of immunogenicity and pathogen transmission, while synthetic materials need functionalization or blending to improve their biocompatibility. In addition, the traditional top-down fabrication techniques do not recreate the native tissue microarchitecture. Self-assembling ultrashort peptides (SUPs) are promising chemically synthesized natural materials that self-assemble into three-dimensional nanofibrous hydrogels resembling the extracellular matrix (ECM). Here, we use a modular tissue-engineering approach, embedding SUP microgels loaded with human umbilical vein endothelial cells (HUVECs) into a 3D SUP hydrogel containing human dermal fibroblast neonatal (HDFn) cells to trigger angiogenesis. The SUPs IVFK and IVZK were used to fabricate microgels that gel in a water-in-oil emulsion using a microfluidic droplet generator chip. The fabricated SUP microgels are round structures that are 300–350 μm diameter in size and have ECM-like topography. In addition, they are stable enough to keep their original size and shape under cell culture conditions and long-term storage. When the SUP microgels were used as microcarriers for growing HUVECs and HDFn cells on the microgel surface, cell attachment, stretching, and proliferation could be demonstrated. Finally, we performed an angiogenesis assay in both SUP hydrogels using all SUP combinations between micro- and bulky hydrogels. Endothelial cells were able to migrate from the microgel to the surrounding area, showing angiogenesis features such as sprouting, branching, coalescence, and lumen formation. Although both SUP hydrogels support vascular network formation, IVFK outperformed IVZK in terms of vessel network extension and branching. Overall, these results demonstrated that cell-laden SUP microgels have great potential to be used as a microcarrier cell delivery system, encouraging us to study the angiogenesis process and to develop vascularized tissue-engineering therapies.
    • Protein phosphatase 1 regulates atypical mitotic and meiotic division in Plasmodium sexual stages

      Zeeshan, Mohammad; Pandey, Rajan; Subudhi, Amit; Ferguson, David J P; Kaur, Gursimran; Rashpa, Ravish; Nugmanova, Raushan; Brady, Declan; Bottrill, Andrew R.; Vaughan, Sue; Brochet, Mathieu; Bollen, Mathieu; Pain, Arnab; Holder, Anthony A.; Guttery, David S.; Tewari, Rita (Communications Biology, Springer Science and Business Media LLC, 2021-06-18) [Article]
      AbstractPP1 is a conserved eukaryotic serine/threonine phosphatase that regulates many aspects of mitosis and meiosis, often working in concert with other phosphatases, such as CDC14 and CDC25. The proliferative stages of the malaria parasite life cycle include sexual development within the mosquito vector, with male gamete formation characterized by an atypical rapid mitosis, consisting of three rounds of DNA synthesis, successive spindle formation with clustered kinetochores, and a meiotic stage during zygote to ookinete development following fertilization. It is unclear how PP1 is involved in these unusual processes. Using real-time live-cell and ultrastructural imaging, conditional gene knockdown, RNA-seq and proteomic approaches, we show that Plasmodium PP1 is implicated in both mitotic exit and, potentially, establishing cell polarity during zygote development in the mosquito midgut, suggesting that small molecule inhibitors of PP1 should be explored for blocking parasite transmission.
    • All-Polycarbonate Graft Copolymers with Tunable Morphologies by Metal-Free Copolymerization of CO2 with Epoxides

      Alagi, Prakash; Zapsas, Georgios; Hadjichristidis, Nikos; Hong, Sung Chul; Gnanou, Yves; Feng, Xiaoshuang (Macromolecules, American Chemical Society (ACS), 2021-06-18) [Article]
      Brush-type macromolecules (BMs) have attracted much attention over the past decades because of their unique properties and potential applications in nanoscience, drug-delivery systems, and photonics. A two-step strategy of synthesis of polycarbonate-grafted copolymers with either star-shaped or brushtyped morphologies using a “grafting from” approach is reported; the backbone in these all-polycarbonate graft copolymers is made of poly(cyclohexene carbonate) (PCHC), and the side grafts are made of poly(propylene carbonate) (PPC). In the first step, poly (vinyl-cyclohexene carbonate) (PVCHC) backbones of two different sizes (PVCHC35, PVCHC283) were prepared by copolymerization of vinyl-cyclohexene oxide (VCHO) with CO2 in the presence of triethylborane (TEB), using tetrabutyl ammonium succinate (TBAS) as the initiator. In the second step, the dangling vinyl double bonds of PVCHC were transformed into carboxylic acid groups. After partial neutralization of the latter using tetrabutyl ammonium hydroxide, the PPC grafts could be grown from the backbone carboxylic sites by copolymerization of propylene oxide (PO) with CO2 in the presence of TEB. Before attempting the synthesis of the above all-polycarbonate grafted copolymers, we check the viability of the above synthetic strategy by preparing graft copolymers made of a polymethacrylate backbone and PPC side grafts. In the latter case, the backbone was generated by reversible addition−fragmentation chain-transfer (RAFT) polymerization of methacrylic acid (MAA), followed by the growth of PPC side grafts using the backbone carboxylates as initiating sites. In both cases (PVCHC-g-PPC and PMAA-g-PPC), two types of architectures corresponding to two different morphologies were synthesized: star-shaped morphologies were obtained from rather short backbones, and relatively long grafts, on the one hand, and semiflexible cylinders were grown from rather long backbones and short grafts. These various structures were characterized by nuclear magnetic resonance (NMR) and gel permeation chromatography/light scattering (GPC/LS), and their morphologies were further investigated by atomic force microscopy (AFM). The reported synthetic method provides a robust way to synthesize well-defined polycarbonates with either star-type or brush-type morphologies and graft copolymers made of polyacrylate backbones and polycarbonate grafts. Thermal and mechanical properties of these graft copolymers were also investigated.
    • Synthesis of Chitosan-La2O3 Nanocomposite and Its Utility as a Powerful Catalyst in the Synthesis of Pyridines and Pyrazoles

      Khalil, Khaled D.; Riyadh, Sayed M.; Jaremko, Mariusz; Farghaly, Thoraya A.; Hagar, Mohamed (Molecules, MDPI AG, 2021-06-17) [Article]
      Recently, the development of nanocatalysts based on naturally occurring polysaccharides has received a lot of attention. Chitosan (CS), as a biodegradable and biocompatible polysaccharide, is considered to be an excellent template for the design of a hybrid biopolymer-based metal oxide nanocomposite. In this case, lanthanum oxide nanoparticles doped with chitosan at different weight percentages (5, 10, 15, and 20 wt% CS/La2O3) were prepared via a simple solution casting method. The prepared CS/La2O3 nanocomposite solutions were cast in a Petri dish in order to produce the developed catalyst, which was shaped as a thin film. The structural features of the hybrid nanocomposite film were studied by FTIR, SEM, and XRD analytical tools. FTIR spectra confirmed the presence of the major characteristic peaks of chitosan, which were modified by interaction with La2O3 nanoparticles. Additionally, SEM graphs showed dramatic morphological changes on the surface of chitosan, which is attributed to surface adsorption with La2O3 molecules. The prepared CS/La2O3 nanocomposite film (15% by weight) was investigated as an effective, recyclable, and heterogeneous base catalyst in the synthesis of pyridines and pyrazoles. The nanocomposite used was sufficiently stable and was collected and reused more than three times without loss of catalytic activity.
    • Robust, Long-Term, and Exceptionally Sensitive Microneedle-Based Bioimpedance Sensor for Precision Farming

      Bu Khamsin, Abdullah; Moussi, Khalil; Tao, Ran; Lubineau, Gilles; Blilou, Ikram; Salama, Khaled N.; Kosel, Jürgen (Advanced Science, Wiley, 2021-06-17) [Article]
      Precision farming has the potential to increase global food production capacity whilst minimizing traditional inputs. However, the adoption and impact of precision farming are contingent on the availability of sensors that can discern the state of crops, while not interfering with their growth. Electrical impedance spectroscopy offers an avenue for nondestructive monitoring of crops. To that end, it is reported on the deployment of impedimetric sensors utilizing microneedles (MNs) that can be used to pierce the waxy exterior of plants to obtain sensitive impedance spectra in open-air settings with an average relative noise value of 3.83%. The sensors are fabricated using a novel micromolding and release method that is compatible with UV photocurable and thermosetting polymers. Assessments of the quality of the MNs under scanning electron microscopy show that the replication process is high in fidelity to the original design of the master mold and that it can be used for upward of 20 replication cycles. The sensor's performance is validated against conventional planar sensors for obtaining the impedance values of Arabidopsis thaliana. As a change is detected in impedance due to lighting and hydration, this raises the possibility for their widespread use in precision farming.
    • Detection of SARS-CoV-2 variants requires urgent global coordination

      Duarte, Carlos M.; Jamil, Tahira; Gojobori, Takashi; Alam, Intikhab (International Journal of Infectious Diseases, Elsevier BV, 2021-06-17) [Article]
      Objectives We assessed the effort deployed by different nations and territories to sequence SARS-CoV-2 isolates, thus allowing the detection of variants, known and novel, of concern. Design We analyzed the sources of over one million full genome sequences of SARS-CoV-2 virus available in the COVID-19 virus Mutation Tracker (CovMT) to determine the number of variants in the RBD region of the genome determining infectivity detected in the various nations and territories. Results The number of variants detected increased as the square root of sequencing effort of sequencing effort by nations. Eight nations contributed 79% of all SARS-CoV-2 isolates sequenced, with 2/3’s of all unique variants, adding to 1118 RBD variants, reported by 5 nations. The median number of isolates sequenced required to detect, on average, one novel RBD variant is 24.05, a threshold only achieved by 70 nations. Conclusions Many developing nations have not contributed any sequences due to lack of capacity, with a risk of dangerous virus variants in these undersampled regions spreading globally before being detected. A collaborative program to sequence SARS-CoV-2 isolates, and other pathogens of concern, is needed to monitor, track and control the pandemic.
    • Detection uncertainty of fractional optical vortex with angle indeterminacy in different transformation-based OAM-sorting systems

      Shangguan, Huangcheng; Zheng, Shuiqin (Optics and Lasers in Engineering, Elsevier BV, 2021-06-17) [Article]
      This paper reveals and compares the detection uncertainty of fractional optical vortex (FOV) in several coordinate transformation-based OAM sorting systems. It is found that the azimuth of the phase mutation of FOV will significantly affect the output results. Hence, there will be a detection uncertainty when analyzing FOV with angle indeterminacy, but this uncertainty is not come from the FOV itself, but from the OAM sorting system. Therefore, FOV with angular uncertainty could be a tool to evaluate the robustness of the OAM sorting system. From the simulation and comparison, the features of the earliest proposed log-polar sorting method and the improved beam-copying, spiral-transformation sorting methods are studied. We conclude that the beam-copying sorting method is better for OAM spectrum analysis, and the spiral-transformation sorting with appropriate parameters performs better for average OAM detection.
    • Analysis of the temporal and spatial variability of whale shark (Rhincodon typus) aggregation in the South Ari Marine Protected Area, Maldives, Indian Ocean

      Valsecchi, S.; Lanfredi, C.; Azzellino, A.; Savini, A.; Bracchi, V. A.; Marchese, Fabio; Hancock, J.; Rees, R.; Cánovas Pérez, C. (The European Zoological Journal, Informa UK Limited, 2021-06-17) [Article]
      Whale sharks are known to aggregate in coastal areas. In the South Ari Marine Protected Area (Maldives) a aggregation, mostly represented by young males with a high level of residency, has been described in the literature. Despite the worldwide interest in the natural resources of the Maldives, this population is increasingly subjected to anthropogenic pressure and major concern regards the flourishing tourist industry. In this study, data collected by the Maldives Whale Shark Research Programme between 2014 and 2017 have been used to detect both temporal and spatial patterns of occurrence. Favourable environmental conditions to visually detect whale sharks have been defined for the studied area. Accordingly, a total of 1077 shark encounters have been analysed in this study. Environmental conditions (i.e. sea surface temperature, monsoon occurrence) have been used to detect possible factors affecting the spatial and temporal variability of Rhincodon typus aggregations. A two-way ANOVA has been performed to detect temporal trends in animal occurrence, sea surface temperature pattern and to investigate the sea bottom depth variability during encounters. Significant differences in the monthly occurrence of whale sharks within the same year and among different years have been detected. Similar patterns have been observed for environmental parameters such as sea surface temperature and depth. A different spatial distribution has also been detected as a function of the Indian Monsoon reversal (north-eastern and south-western) affecting the area. During the northeast monsoon period, whale sharks appeared to concentrate in a smaller longitudinal range closer to the western-central part of the MPA, where deeper water conditions occur due to the proximity of a deep depression (submarine canyon). Results from this study provide new pieces of information for the implementation of dedicated management actions to protect the whale sharks population inhabiting the South Ari Marine Protected Area.
    • State of the Art and Prospects for Halide Perovskite Nanocrystals

      Dey, Amrita; Ye, Junzhi; De, Apurba; Debroye, Elke; Ha, Seung Kyun; Bladt, Eva; Kshirsagar, Anuraj S.; Wang, Ziyu; Yin, Jun; Wang, Yue; Quan, Li Na; Yan, Fei; Gao, Mengyu; Li, Xiaoming; Shamsi, Javad; Debnath, Tushar; Cao, Muhan; Scheel, Manuel A.; Kumar, Sudhir; Steele, Julian A.; Gerhard, Marina; Chouhan, Lata; Xu, Ke; Wu, Xian-gang; Li, Yanxiu; Zhang, Yangning; Dutta, Anirban; Han, Chuang; Vincon, Ilka; Rogach, Andrey L.; Nag, Angshuman; Samanta, Anunay; Korgel, Brian A.; Shih, Chih-Jen; Gamelin, Daniel R.; Son, Dong Hee; Zeng, Haibo; Zhong, Haizheng; Sun, Handong; Demir, Hilmi Volkan; Scheblykin, Ivan G.; Mora-Seró, Iván; Stolarczyk, Jacek K.; Zhang, Jin Z.; Feldmann, Jochen; Hofkens, Johan; Luther, Joseph; Pérez-Prieto, Julia; Li, Liang; Manna, Liberato; Bodnarchuk, Maryna I.; Kovalenko, Maksym V.; Roeffaers, Maarten B. J.; Pradhan, Narayan; Mohammed, Omar F.; Bakr, Osman; Yang, Peidong; Müller-Buschbaum, Peter; Kamat, Prashant V.; Bao, Qialiang; Zhang, Qiao; Krahne, Roman; Galian, Raquel E.; Stranks, Samuel D.; Bals, Sara; Biju, Vasudevanpillai; Tisdale, William A.; Yan, Yong; Hoye, Robert L. Z.; Polavarapu, Lakshminarayana (ACS Nano, American Chemical Society (ACS), 2021-06-17) [Article]
      Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of perovskite nanocrystals and understanding of their properties and applications. In this comprehensive review, researchers having expertise in different fields (chemistry, physics, and device engineering) of metal-halide perovskite nanocrystals have joined together to provide a state of the art overview and future prospects of metal-halide perovskite nanocrystal research.
    • Uncertainty Quantification and Bayesian Inference of Cloud Parameterization in the NCAR Single Column Community Atmosphere Model (SCAM6)

      Pathak, Raju; Dasari, Hari Prasad; El Mohtar, Samah; Subramanian, Aneesh; Sahany, Sandeep; Mishra, Saroj K; Knio, Omar; Hoteit, Ibrahim (Frontiers in Climate, Frontiers, 2021-06-16) [Article]
      Uncertainty quantification (UQ) in weather and climate models is required to assess the sensitivity of their outputs to various parameterization schemes and thereby improve their consistency with observations. Herein, we present an efficient UQ and Bayesian inference for the cloud parameters of the NCAR Single Column Atmosphere Model (SCAM6) using surrogate models based on a polynomial chaos expansion. The use of a surrogate model enables to efficiently propagate uncertainties in parameters into uncertainties in model outputs. We investigated eight uncertain parameters: the auto-conversion size threshold for ice to snow (dcs), the fall speed parameter for stratiform cloud ice (ai), the fall speed parameter for stratiform snow (as), the fall speed parameter for cloud water (ac), the collection efficiency of aggregation ice (eii), the efficiency factor of the Bergeron effect (berg_eff), the threshold maximum relative humidity for ice clouds (rhmaxi), and the threshold minimum relative humidity for ice clouds (rhmini). We built two surrogate models using two non-intrusive methods: spectral projection (SP) and basis pursuit denoising (BPDN). Our results suggest that BPDN performs better than SP as it enables to filter out internal noise during the process of fitting the surrogate model. Five out of the eight parameters (namely dcs, ai, rhmaxi, rhmini, and eii) account for most of the variance in predicted climate variables (e.g., total precipitation, cloud distribution, shortwave and longwave cloud forcing, ice and liquid water path). A first-order sensitivity analysis reveals that dcs contributes approximately 40–80% of the total variance of the climate variables, ai around 15–30%, and rhmaxi, rhmini, and eii around 5–15%. The second- and higher-order effects contribute approximately 20% and 11%, respectively. The sensitivity of the model to these parameters was further explored using response curves. A Markov chain Monte Carlo (MCMC) sampling algorithm was also implemented for the Bayesian inference of dcs, ai, as, rhmini, and berg_eff using cloud distribution data collected at the Southern Great Plains (USA). Our study has implications for enhancing our understanding of the physical mechanisms associated with cloud processes leading to uncertainty in model simulations and further helps to improve the models used for their assessment.
    • Integrated solar-driven PV cooling and seawater desalination with zero liquid discharge

      Wang, Wenbin; Aleid, Sara; Shi, Yifeng; Zhang, Chenlin; Li, Renyuan; Wu, Mengchun; Zhuo, Sifei; Wang, Peng (Joule, Elsevier BV, 2021-06-16) [Article]
      Utilizing the ‘‘waste heat’’ of solar cells for desalination enables the simultaneous production of freshwater and electricity and represents low barrier-of-entry electricity and freshwater supplies to off-grid communities for point of consumption. Herein, guided by theoretical modeling, this project demonstrated that a higher freshwater production rate and a lower solar cell temperature could be achieved simultaneously. With a five-stage photovoltaics-membrane distillation-evaporative crystallizer (PME), we experimentally demonstrated a high and stable freshwater production rate of 2.45 kg m2 h1 and a reduced solar cell temperature of 47 C under 1 sun irradiation, as compared to 62 C of the same solar cell working alone. The reduced solar cell temperature led to an 8% increase in its electricity production. Moreover, the concentrated brine produced in the process was fully evaporated by the underlying evaporative crystallizer, achieving zero liquid discharge. We expect that our work will have important implications for the understanding and advancement of solar distillation.
    • Tumor-Associated-Macrophage-Membrane-Coated Nanoparticles for Improved Photodynamic Immunotherapy

      Chen, Cailing; Song, Meiyu; Du, Yangyang; Yu, Ying; Li, Chunguang; Han, Yu; Yan, Fei; Shi, Zhan; Feng, Shouhua (Nano Letters, American Chemical Society (ACS), 2021-06-16) [Article]
      Cell-membrane-coated nanoparticles have emerged as a promising antitumor therapeutic strategy. However, the immunologic mechanism remains elusive, and there are still crucial issues to be addressed including tumor-homing capacity, immune incompatibility, and immunogenicity. Here, we reported a tumor-associated macrophage membrane (TAMM) derived from the primary tumor with unique antigen-homing affinity capacity and immune compatibility. TAMM could deplete the CSF1 secreted by tumor cells in the tumor microenvironment (TME), blocking the interaction between TAM and cancer cells. Especially, after coating TAMM to upconversion nanoparticle with conjugated photosensitizer (NPR@TAMM), NPR@TAMM-mediated photodynamic immunotherapy switched the activation of macrophages from an immunosuppressive M2-like phenotype to a more inflammatory M1-like state, induced immunogenic cell death, and consequently enhanced the antitumor immunity efficiency via activation of antigen-presenting cells to stimulate the production of tumor-specific effector T cells in metastatic tumors. This TAM-membrane-based photodynamic immunotherapy approach offers a new strategy for personalized tumor therapy.
    • Concurrent cationic and anionic perovskite defect passivation enables 27.4% perovskite/silicon tandems with suppression of halide segregation

      Isikgor, Furkan Halis; Furlan, Francesco; Liu, Jiang; Ugur, Esma; Eswaran, Mathan Kumar; Subbiah, Anand Selvin; Yengel, Emre; de Bastiani, Michele; Harrison, George T.; Zhumagali, Shynggys; Howells, Calvyn Travis; Aydin, Erkan; Wang, Mingcong; Gasparini, Nicola; Allen, Thomas; Rehman, Atteq Ur; Van Kerschaver, Emmanuel; Baran, Derya; McCulloch, Iain; Anthopoulos, Thomas D.; Schwingenschlögl, Udo; Laquai, Frédéric; De Wolf, Stefaan (Joule, Elsevier BV, 2021-06-16) [Article]
      Stable and efficient perovskite/silicon tandem solar cells require defect passivation and suppression of light-induced phase segregation of the wide-band-gap perovskite. Here, we report how molecules containing both electron-rich and electron-poor moieties, such as phenformin hydrochloride (PhenHCl), can satisfy both requirements, independent of the perovskite’s surface chemical composition and its grain boundaries and interfaces. PhenHClpassivated wide-band-gap ( 1.68 eV) perovskite p-i-n single-junction solar cells deliver an open-circuit voltage (VOC) 100 mV higher than control devices, resulting in power conversion efficiencies (PCEs) up to 20.5%. These devices do not show any VOC losses after more than 3,000 h of thermal stress at 85C in a nitrogen ambient. Moreover, PhenHCl passivation improves the PCE of textured perovskite/silicon tandem solar cells from 25.4% to 27.4%. Our findings provide critical insights for improved passivation of metal halide perovskite surfaces and the fabrication of highly efficient and stable perovskite-based single-junction and tandem solar cells.
    • Molecular Doping Directed by a Neutral Radical

      Liu, Jian; van der Zee, Bas; Villava, Diego R.; Ye, Gang; Kahmann, Simon; Kamperman, Max; Dong, Jingjin; Qiu, Li; Portale, Giuseppe; Loi, Maria A.; Hummelen, Jan C.; Chiechi, Ryan C.; Baran, Derya; Koster, L. Jan Anton (ACS Applied Materials & Interfaces, American Chemical Society (ACS), 2021-06-16) [Article]
      Molecular doping makes possible tunable electronic properties of organic semiconductors, yet a lack of control of the doping process narrows its scope for advancing organic electronics. Here, we demonstrate that the molecular doping process can be improved by introducing a neutral radical molecule, namely nitroxyl radical (2,2,6,6-teramethylpiperidin-i-yl) oxyl (TEMPO). Fullerene derivatives are used as the host and 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazoles (DMBI-H) as the n-type dopant. TEMPO can abstract a hydrogen atom from DMBI-H and transform the latter into a much stronger reducing agent DMBI•, which efficiently dopes the fullerene derivative to yield an electrical conductivity of 4.4 S cm–1. However, without TEMPO, the fullerene derivative is only weakly doped likely by a hydride transfer following by an inefficient electron transfer. This work unambiguously identifies the doping pathway in fullerene derivative/DMBI-H systems in the presence of TEMPO as the transfer of a hydrogen atom accompanied by electron transfer. In the absence of TEMPO, the doping process inevitably leads to the formation of less symmetrical hydrogenated fullerene derivative anions or radicals, which adversely affect the molecular packing. By adding TEMPO we can exclude the formation of such species and, thus, improve charge transport. In addition, a lower temperature is sufficient to meet an efficient doping process in the presence of TEMPO. Thereby, we provide an extra control of the doping process, enabling enhanced thermoelectric performance at a low processing temperature.
    • Synthesis, Structural Studies, and Anticancer Properties of [CuBr(PPh3)2(4,6-Dimethyl-2-Thiopyrimidine-κS]

      Babgi, Bandar A.; Alsayari, Jalal; Davaasuren, Bambar; Emwas, Abdul-Hamid M.; Jaremko, Mariusz; Abdellattif, Magda H.; Hussien, Mostafa A. (Crystals, MDPI AG, 2021-06-16) [Article]
      CuBr(PPh3)2(4,6-dimethylpyrimidine-2-thione) (Cu-L) was synthesized by stirring CuBr(PPh3)3 and 4,6-dimethylpyrimidine-2-thione in dichloromethane. The crystal structure of Cu-L was obtained, and indicated that the complex adopts a distorted tetrahedral structure with several intramolecular hydrogen bonds. Moreover, a centrosymmetric dimer is formed by the intermolecular hydrogen bonding of the bromine acceptor created by symmetry operation 1−x, 1−y, 1−z to the methyl group (D3 = C42) of the pyrimidine–thione ligand. HSA-binding of Cu-L and its ligand were evaluated, revealing that Cu-L binds to HSA differently than its ligand. The HSA-bindings were modeled by molecular docking, which suggested that Cu-L binds to the II A domain while L binds between the I B and II A domains. Anticancer activities toward OVCAR-3 and HeLa cell lines were tested and indicated the significance of the copper center in enhancing the cytotoxic effect; negligible toxicities for L and Cu-L were observed towards a non-cancer cell line. The current study highlights the potential of copper(I)-phosphine complexes containing thione ligands as therapeutic agents.
    • Quality Evaluation of Epoxy Pore Casts Using Silicon Micromodels: Application to Confocal Imaging of Carbonate Samples

      Hassan, Ahmed; Yutkin, Maxim; Chandra, Viswasanthi; Patzek, Tadeusz (Applied Sciences, MDPI AG, 2021-06-16) [Article]
      Pore casting refers to filling the void spaces of porous materials with an extraneous fluid, usually epoxy resin, to obtain a high-strength composite material, stabilize a fragile porous structure, produce a three-dimensional replica of the pore space, or provide imaging contrast. Epoxy pore casting may be accompanied by additional procedures, such as etching, in which the material matrix is dissolved, leaving a clean cast. Moreover, an epoxy resin may be mixed with fluorophore substances to allow fluorescence imaging. Our work aims to investigate and optimize the epoxy pore casting procedure parameters, for example, impregnation pressure. We use silicon micromodels as a reference to validate the key parameters of high-pressure resin impregnation. We demonstrate possible artifacts and defects that might develop during impregnation with resin, e.g., resin shrinkage and gas trapping. In the end, we developed an optimized protocol to produce high-quality resin pore casts for high-resolution 3D imaging and the description of microporosity in micritic carbonates. In our applications, the high-quality pore casts were acid-etched to remove the non-transparent carbonate material, making the pore casts suitable for imaging with Confocal Laser Scanning Microscopy (CLSM). In addition, we evaluate the quality of our etching procedure using micro-computed tomography (micro-CT) scans of the pre- and post-etched samples and demonstrate that the etched epoxy pore casts represent the pore space of microporous carbonate rock samples with high fidelity.