Assessment of Five Concrete Types as Candidate Shielding Materials for a Compact Radiation Source Based on the IECF.

A radiation source based on the inertial electrostatic confinement fusion (IECF) system is being developed for multidisciplinary research applications. The radiation outputs from the IECF system are 2.45 MeV fast neutrons and the associated co-generated X-rays with an energy less than 3 MeV. A radiation shielding study has been performed on five types of concrete to define the most efficient material for the shielding design of the system. The proposed materials were ilmenite-magnetite concrete (IMC), ordinary concrete-1 (OC-1), barite-containing concrete (BC), ordinary concrete-2 (OC-2), and serpentine-containing concrete (SC). A numerical model was applied to determine the effective removal cross-section coefficients (∑Rt) for the fast neutrons and the total mass attenuation coefficients (µm), the half-value layer (HVL), the mean free path (MFP), the effective atomic number (Zeff), and effective electron density (Neff) for photons inside the materials. The model considered the radiation source energy and the material properties of the concrete types. The results revealed that the serpentine-containing concrete exhibited the highest ∑Rt with 12 cm of concrete thickness needed to attenuate an incident neutron flux to 1/100 of its initial value. In addition, the BC shows the highest µm with a 38 cm concrete thickness needed to attenuate the 3 MeV energy X-ray flux to 1/100 of its initial value. This study suggests that a 40 cm thickness of SC or BC adequately shields the radiation generated from an IECF system with a maximum particle production rate of up to 1 × 107 n/s.

A Deployable and Cost-Effective Kirigami Antenna for Sub-6 GHz MIMO Applications.

In this work, a low-cost, deployable, integratable, and easy-to-fabricate multiple-input multiple-output (MIMO) Kirigami antenna is proposed for sub-6 GHz applications. The proposed MIMO antenna is inspired by Kirigami art, which consists of four radiating and parasitic elements. The radiating and parasitic elements are composed of a rectangular stub. These elements are placed in such a way that they can provide polarization diversity. The proposed MIMO antenna is designed and fabricated using a soft printed board material called flexible copper-clad laminate (FCCL). It is observed from the results that the proposed MIMO antenna resonates in the 2.5 GHz frequency band, with a 10 dB reflection coefficient bandwidth of 860 MHz ranging from 2.19 to 3.05 GHz. It is worthwhile to mention that the isolation between adjacent radiating elements is higher than 15 dB. In addition, the peak realized gain of the MIMO antenna is around 11 dBi, and the total efficiency is more than 90% within the band of interest. Moreover, the envelope correlation coefficient (ECC) is noted to be less than 0.003, and the channel capacity is ≥17 bps/Hz. To verify the simulated results, a prototype was fabricated, and excellent agreement between the measured and computed results was observed. By observing the performance attributes of the proposed design, it can be said that there are many applications in which this antenna can be adopted. Because of its low profile, it can be used in 5G small-cell mobile MIMO base stations, autonomous light mobility vehicles, and other applications.

Sheltered Neurosurgery During COVID-19: The Emory Experience.

BACKGROUND: The 2019 novel coronavirus disease (COVID-19) pandemic has directly and indirectly impacted health care systems, including residency programs. Social distancing, cancellation of elective cases, and staff re-deployment have compromised clinical and academic teaching. We describe the neurosurgical experience at Emory University during the COVID-19 pandemic and the impact of COVID-19-related policies on resident experience. METHODS: We retrospectively reviewed all neurosurgical cases performed at Emory University Hospital between March 16, the day cancellation of elective cases was effective, and April 15, 2020, and the same period in the preceding 3 years. For the study period, we collected the number of cases and their distribution by subspecialty along with total hospital charges. RESULTS: Compared with an average of 606 cases performed during the study period over the past 3 years, only 145 neurosurgical cases were performed between March 16 and April 15, 2020, which corresponds to an 80% reduction in case volume and 66% decrease in hospital revenue in 2020. When divided by subspecialty, the most significant reduction was observed in functional (84%; P < 0.01) followed by spine (78%; P < 0.01) surgery, although all subspecialties were significantly impacted. Assessing junior resident experience, we observed a significant reduction in number of neurosurgical admissions (47%; P < 0.01) and bedside procedures (59%; P < 0.01) in the study period in 2020 compared with the past 3 years, with no significant reduction in number of consultations (17%; P > 0.1). CONCLUSIONS: Even at academic centers that were not hugely impacted by the COVID-19 pandemic, prophylactic and preparedness measures still exhibited an unprecedented toll on neurosurgical resident and fellow experience.

Dissecting the Financial Relationship Between Industry and Academic Neurosurgery.

BACKGROUND: Established by the Centers for Medicare and Medicaid Services (CMS), the Open Payments Database (OPD) has reported industry payments to physicians since August 2013. OBJECTIVE: To evaluate the frequency, type, and value of payments received by academic neurosurgeons in the United States over a 5-yr period (2014-2018). METHODS: The OPD was queried for attending neurosurgeons from all neurosurgical training programs in the United States (n = 116). Information from the OPD was analyzed for the entire cohort as well as for comparative subgroup analyses, such as career stage, subspecialty, and geographic location. RESULTS: Of all identified neurosurgeons, 1509 (95.0%) received some payment from industry between 2014 and 2018 for a total of 106 171 payments totaling $266 407 458.33. A bimodal distribution was observed for payment number and total value: 0 to 9 (n = 438) vs > 50 (n = 563) and 0-$1000 (n = 418) vs >$10 000 (n = 653), respectively. Royalty/License was the most common type of payment overall (59.6%; $158 723 550.57). The median number (40) and value ($8958.95) of payments were highest for mid-career surgeons. The South-Central region received the most money ($117 970 036.39) while New England received the greatest number of payments (29 423). Spine surgeons had the greatest median number (60) and dollar value ($20 551.27) of payments, while pediatric neurosurgeons received the least (8; $1108.29). Male neurosurgeons received a greater number (31) and value ($6395.80) of payments than their female counterparts (11, $1643.72). CONCLUSION: From 2014 to 2018, payments to academic neurosurgeons have increased in number and value. Dollars received were dependent on geography, career stage, subspecialty and gender.

Innovation, Royalties, and Introduction of the Patent Hirsch Index within U.S. Academic Neurosurgery.

BACKGROUND: Historically, practicing neurosurgeons have been key drivers of neurosurgical innovation. We sought to describe the patents held by U.S. academic neurosurgeons and to explore the relationship between patents and royalties received. METHODS: The Centers for Medicare and Medicaid CMS Open Payments Data was used to identify academic neurosurgeons who had received royalties and royalty amounts during a 5-year period (2013-2017). Online patent databases were used to gather patent details. Patent citations and 5-year individual and departmental patent Hirsch (h)-indexes were calculated. Royalties were correlated with the number of patents, patent citations, and patent h-index. RESULTS: We found that 119 academic neurosurgeons (7.8%) from 57 U.S. teaching programs (48.3%) had received royalty payments; 72 (60.5%) had published 648 patents. All surgeons were men, with approximately one half in the "late" stages of their career (45.3%) and subspecializing in spinal surgery (50.4%). The patented products or devices were most commonly used for spinal surgery (72.1%), with 2010-2019 the most productive period (n = 455; 70.2%). The median number of citations per patent was 32 (range, 0-620), with 33% having ≥100 citations. The highest individual and institutional patent h-index was 95; 25 (34.7%) neurosurgeons had a patent h-index of ≥5. The median total royalty payment per individual neurosurgeon was $111,011 (range, $58.05-$76,715,750.34). Royalties were correlated with the number of patents (Spearman r = 0.37; P ≤ 0.001), citations (Spearman r, 0.38; P ≤ 0.001), and inventor h-index (Spearman r = 0.38; P ≤ 0.001). CONCLUSIONS: Few U.S. academic neurosurgeons (7.8%) receive royalties and hold patents (4.7%), with an even smaller select group having a patent h-index of ≥5 (1.6%).

A Review of Industry Funding in Randomized Controlled Trials Published in the Neurosurgical Literature-The Elephant in the Room.

OBJECTIVE: To analyze the role of industry sponsorship of randomized controlled trials (RCTs) published exclusively in 3 major North American neurosurgical journals. METHODS: Our primary objective was to determine whether an association exists between study conclusion(s) in favor of industry sponsored drugs, devices/implants, or surgical techniques and industry sponsorship. The secondary objective was to describe the quality/quantity of these neurosurgical RCTs. RESULTS: A total of 110 RCTs were analyzed, the majority were published in the Journal of Neurosurgery (85%) and were international in origin (55%). The most common subspecialty was spine (n = 29) and drug study was the most common type (n = 49). Overall quality was good with median Jadad and Detsky scores of 4 (range, 1-5) and 18 (range, 8-21), respectively. There was a statistically significant difference in RCTs with industry funding (31/40, 78%) versus those without (9/70, 13%) that published a favorable conclusion of the new drug, device/implant, or surgical technique (odds ratio [OR], 23.35; P < .0001). Multiple binomial logistic regression analysis identified "number of authors" as mildly protective (OR, 0.79; 95% confidence interval, 0.69-0.91; P = .001) and "industry funding" strongly predictive (OR, 12.34; 95% confidence interval, 2.97-51.29; P = .001) of a positive trial. CONCLUSION: Industry funding was associated with a much greater chance of positive findings in RCTs published in neurosurgical journals. Further efforts are needed to define the relationship between the authors and financial sponsors of neurosurgical research and explore the reasons for this finding.