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12 results on '"Partyka, Paul P."'

4. A Ka-Band InP HBT MMIC Power Amplifier With 19.8:1 IP3/Pdc LFOM at 48 GHz

Author

Kobayashi, Kevin W., Partyka, Paul, Howle, Tim, Sellas, Tony, and Hayden, Leonard

Abstract

This article describes the design and measured performance of a linear efficient Ka -band InP DHBT PA with an IP3/ $\text{P}_{\mathrm {dc}}$ linearity figure of merit (LFOM) of 19.8:1 at 48 GHz and 14.1:1 at 40 GHz. The MMIC PA is based on an InP DHBT technology with peak ${f}_{AT}$ and ${f}_{\mathrm{ max}}$ of $>$ 300 and $>$ 600 GHz, respectively, and achieves among the best LFOM at the Ka -band above 40 GHz from an MMIC-matched amplifier. The amplifier is a single-stage four-way combined design that was optimized for a combination of power and PAE at < 2-dB compression. The linear ${P}_{\mathrm{ 1\,dB}}$ is 21.2 dBm with a PAE of 28.3% and a corresponding IP3 of 36.1 dBm. A remarkable IP3- ${P}_{\mathrm {1\,dB}}\,\,=$ 14.9 dB is obtained which is significantly higher than the 10 dB rule of thumb for semiconductors. At 48 GHz, a peak IP3 of 36.6 dBm and LFOM of 19.8:1 is achieved which is twice better than the low microwave frequency rule-of-thumb of 10:1 for LFOM. Under a 200-MHz QPSK modulation, linear PAEs of 17.4%–19.5% for 5% EVM across a 40–44-GHz band were achieved. This work demonstrates among the highest IP3/ $\text{P}_{\mathrm {dc}}$ LFOM and EVM linear PAE reported for an MMIC above 40 GHz.

Published
2023
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6. How accurate is the neurosurgery literature? A review of references.

Author

Montenegro, Thiago S, Hines, Kevin, Gonzalez, Glenn A, Fatema, Umma, Partyka, Paul P, Thalheimer, Sara, Harrop, James, Montenegro, Thiago S, Hines, Kevin, Gonzalez, Glenn A, Fatema, Umma, Partyka, Paul P, Thalheimer, Sara, and Harrop, James

Abstract

BACKGROUND: The reference list is an important part of academic manuscripts. The goal of this study is to evaluate the reference accuracy in the field of neurosurgery. METHODS: This study examines four major peer-reviewed neurosurgery journals, chosen based on their clinical impact factor: Neurosurgery, J Neurosurg, World Neurosurg, and Acta Neurochir. For each of the four journals, five articles from each of the journal's 12 issues published in 2019 were randomly selected using an online generator. This resulted in a total of 240 articles, 60 from each journal. Additionally, from each article's list of references, one reference was again randomly selected and checked for a citation or quotation error. The chi-square test was used to analyze the association between the occurrence of citation and quotation errors and the presence of hypothesized risk factors that could impact reference accuracy. RESULTS: 62.1% of articles had a minor citation error, 8.33% had a major citation error, 12.1% had a minor quotation error, and 5.8% of articles had a major quotation error. Overall, Acta Neurochir presented with the fewest quotation errors compared with the other journals evaluated. The only association between the frequency of errors and potential markers of reference mistakes was with the length of the bibliography. Surprisingly, this correlation indicated that the articles with longer reference lists had fewer citation errors (p < 0.01). Statistical significance was found between the occurrence of citation errors and the journals of publication (p < 0.01). CONCLUSIONS: In order to advance medical treatment and patient care in neurosurgery, detailed documentation and attention to detail are necessary. The results from this analysis illustrate that improved reference accuracy is required.

Published
2020

11. Fabrication of vascularized scaffolds for the treatment of spinal cord injury

Author

Partyka, Paul P.

Subjects
Blood brain barrier, Blood spinal cord barrier, Lab on a chip, Microfluidic device, Neurovascular interaction, Spinal cord injury, Spinal cord--Regeneration; Tissue engineering, Biomedical Engineering and Bioengineering
Abstract

The overall goal of the research presented here is to evaluate the efficacy of transplanting scaffolds containing central nervous system vasculature to repair spinal cord injury. There are three major phases of this effort: development of a three-dimensional model of central nervous system vasculature, transplantation of a pre-vascularized scaffold and optimization of the biomaterial used to deliver vasculature to the injured spinal cord. This research has produced the first ever compliant, three-dimensional (3D) blood-brain barrier (BBB) vessel. In order to create vascularized scaffolds appropriate for transplantation into a rat model of spinal cord injury, techniques to fabricate and spatially pattern capillary-scale vasculature that maintain the tight junction morphology characteristic of the BBB are described. Both in vitro experiments using neural precursor cells and in vivo studies using the rat model demonstrate that axons grow along the patterned microvasculature, which demonstrates the potential of harnessing neurovascular interaction as a novel strategy to regenerate the central nervous system. The third phase of the dissertation focuses on improving the biomaterial composition to enhance the infiltration of host axons into the scaffold. Specifically, the permissivity of a RADA-16I nanofiber peptide material is evaluated by measuring axon growth and levels of serotonin receptors within the scaffold. Taken together, this work advances the field of tissue engineering and regenerative medicine by demonstrating the potential of vascularized scaffolds to repair the damaged spinal cord.

Published
2020

12. Reference accuracy in spine surgery.

Author

Montenegro TS, Hines K, Partyka PP, and Harrop J

Abstract

Objective: The references list is an important part of a scientific article that serves to confirm the accuracy of the authors' statements. The goal of this study was to evaluate the reference accuracy in the field of spine surgery., Methods: Four major peer-reviewed spine surgery journals were chosen for this study based on their subspecialty clinical impact factors. Sixty articles per journal were selected from 12 issues each of The Spine Journal, Spine, and Journal of Neurosurgery: Spine, and 40 articles were selected from 8 issues of Global Spine Journal, for a total of 220 articles. All the articles were published in 2019 and were selected using computer-generated numbers. From the references list of each article, one reference was again selected by using a computer-generated number and then checked for citation or quotation errors., Results: The results indicate that 84.1% of articles have a minor citation error, 4.5% of articles have a major citation error, 9.5% of articles have a minor quotation error, and 9.1% of articles have a major quotation error. Journal of Neurosurgery: Spine had the fewest citation errors compared with the other journals evaluated in this study. Using chi-square analysis, no association was determined between the occurrence of errors and potential markers of reference mistakes. Still, statistical significance was found between the occurrence of citation errors and the spine journals tested., Conclusions: In order to advance medical treatment and patient care in spine surgery, detailed documentation and attention to detail are necessary. The results from this study illustrate that improved reference accuracy is required.

Published
2020
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