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1. Thin Film Enabled Engineered Substrate for Miniaturized Antennas with Improved Bandwidth

   https://doi.org/10.1109/IEEECONF35879.2020.9329840  

   Ge, Jinqun; Wang, Guoan (July 2020, 2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting)

   null (Ed.)

   This paper presents a novel engineered substrate enabled by patterned Permalloy (Ni 80 Fe 20 , Py) thin films for the development of miniaturized antenna with improved bandwidth. The perspective substrate is implemented with multiple layers of 100 nm thick Py thin film patterns embedded on arbitrary microwave substrate, and each Py layer consists of an array of Py patterns with a dimension of 15μm×40μm and 5 μm gaps among them to suppress the magnetic loss. An equivalent permeability of 2.398 is achieved for engineered substrate embedding with 10 layers of Py thin films. A simple patch antenna has been implemented on the engineered substrate to demonstrate the efficacy of designing miniaturized antenna with improved bandwidth, compared to antenna on regular substrate, results show that the developed antenna on engineered substrate has a size reduction of 47.3% and an improved bandwidth of 49.6%. 

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2. Thin Film Enabled Tunable Engineered Substrate for Reconfigurable RF and Microwave Applications

   https://doi.org/10.1109/IWS49314.2020.9360202  

   Ge, Jinqun; Peng, Yujia; West, David; Wang, Guoan (September 2020, 2020 IEEE MTT-S International Wireless Symposium (IWS))

   null (Ed.)

   This paper presents a methodology in the development of miniaturized and electrically tunable RF and Microwave passives with engineered substrate which has high and electrically tunable effective permeability. The perspective substrate is implemented with multiple layers of 100 nm thick Permalloy (Py) thin film patterns embedded on Silicon substrate, and each Py layer consists of an array of 15μm×40μm Py patterns with 5 μm gaps among them to suppress the magnetic loss. The effective permeability of the single layer and ten layers of Py enabled substrate is tunable by the static magnetic field produced from the applied DC current providing a tunability of 3.3% and 18.8%, respectively. Passives are developed on the proposed engineered substrate with a single layer embedded Py to demonstrate the efficacy of the engineered substrate on the design of arbitrary tunable components. Results show that the developed transmission line-based phase shifter provides continuous 90° phase shift from 0.956 GHz to 1.01GHz, and the center frequency of the bandpass filter shifts from 2.42GHz to 2.56GHz continuously. 

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3. Interface induced uniaxial magnetic anisotropy and modified domain patterns in crosslinked silica aerogel/Ni80Fe20 heterostructures

   https://doi.org/10.1007/s00339-025-08449-3  

   Islam, K_Z; Timsina, D.; Sabri, F.; Pollard, S_D (March 2025, Applied Physics A)

   Abstract Silica aerogels have emerged as promising candidates as platforms for a variety of devices, including those used for magnetic logic and sensing. However, their non-planar structure also poses challenges for their use as substrates for thin film devices. For example, substrate disorder is established to strongly influence anisotropy in thin film magnetic materials. Here, we evaluate the substrate effect on induced uniaxial anisotropy in permalloy (Py) thin films and patterned structures, wherein the uniaxial anisotropy is clearly linked to a directionality of the magnetization hysteresis and modifications to zero field domain structures relative to a standard thermally oxidized Si substrate. The strength and direction of this anisotropy vary with location, indicating its non-uniform nature, and is estimated to be as large as 700 J/m³for 25 nm thick permalloy films, and decreases with increasing Py thickness. This substrate induced anisotropy is strong enough to modify the domain structures present in patterned magnetic elements and can have significant implications for the development of magnetic devices on aerogel substrates. Results are compared and found to be consistent with micromagnetic modelling of expected domain structures. 

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4. Chemoproteomic Profiling of Protein Substrates of a Major Lysine Acetyltransferase in the Native Cellular Context

   https://doi.org/10.1021/acschembio.1c00935  

   Song, Jiabao; Ngo, Liza; Bell, Kaylyn; Zheng, Y. George (April 2022, ACS Chemical Biology)

   The family of lysine acetyltransferases (KATs) regulates epigenetics and signaling pathways in eukaryotic cells. So far, knowledge of different KAT members contributing to the cellular acetylome is limited, which limits our understanding of biological functions of KATs in physiology and disease. Here, we found that a clickable acyl-CoA reporter, 3-azidopropanoyl CoA (3AZ-CoA), presented remarkable cell permeability and effectively acylated proteins in cells. We rationally engineered the major KAT member, histone acetyltransferase 1 (HAT1), to generate its mutant forms that displayed excellent bio-orthogonal activity for 3AZ-CoA in substrate labeling. We were able to apply the bio-orthogonal enzyme–cofactor pair combined with SILAC proteomics to achieve HAT1 substrate targeting, enrichment, and proteomic profiling in living cells. A total of 123 protein substrates of HAT1 were disclosed, underlining the multifactorial functions of this important enzyme than hitherto known. This study demonstrates the first example of utilizing bio-orthogonal reporters as a chemoproteomic strategy for substrate mapping of individual KAT isoforms in the native biological contexts. 

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5. Electronic structure of cobalt valence tautomeric molecules in different environments

   https://doi.org/10.1039/d2nr06834f  

   Mishra, Esha; Ekanayaka, Thilini K.; Panagiotakopoulos, Theodoros; Le, Duy; Rahman, Talat S.; Wang, Ping; McElveen, Kayleigh A.; Phillips, Jared P.; Zaid Zaz, M.; Yazdani, Saeed; et al (January 2022, Nanoscale)

   Future molecular microelectronics require the electronic conductivity of the device to be tunable without impairing the voltage control of the molecular electronic properties. This work reports the influence of an interface between a semiconducting polyaniline polymer or a polar poly-D-lysine molecular film and one of two valence tautomeric complexes, i.e. , [Co III (SQ)(Cat)(4-CN-py) 2 ] ↔ [Co II (SQ) 2 (4-CN-py) 2 ] and [Co III (SQ)(Cat)(3-tpp) 2 ] ↔ [Co II (SQ) 2 (3-tpp) 2 ]. The electronic transitions and orbitals are identified using X-ray photoemission, X-ray absorption, inverse photoemission, and optical absorption spectroscopy measurements that are guided by density functional theory. Except for slightly modified binding energies and shifted orbital levels, the choice of the underlying substrate layer has little effect on the electronic structure. A prominent unoccupied ligand-to-metal charge transfer state exists in [Co III (SQ)(Cat)(3-tpp) 2 ] ↔ [Co II (SQ) 2 (3-tpp) 2 ] that is virtually insensitive to the interface between the polymer and tautomeric complexes in the Co II high-spin state. 

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