Mitigating slice cross-talk in multi-slice multi-echo spin echo T2 mapping.

PURPOSE: To investigate whether a T2 inter-slice variation could occur when a multi-slice multi-echo spin echo (MESE) sequence is used for image acquisition and to propose an enhanced method for reconstructing T2 maps that can effectively address and correct these variations. METHODS: Bloch simulations were performed accounting for the direct saturation effect to evaluate magnetization changes in multi-slice 2D MESE sequence. Experimental phantom scans were performed to validate these simulations. An improved version of the dictionary-based reconstruction approach was proposed, enabling the creation of a multi-slice dictionary of echo modulation curves (EMC). The corresponding method has been assayed considering inter-slice T2 variation with phantoms and in lower leg. RESULTS: Experimental and numerical study illustrate that direct saturation leads to a bias of EMCs. This bias during the T2 maps reconstructions using original single-slice EMC-dictionary method led to inter-slice T2 variation of 2.03% in average coefficient of variation (CV) in agarose phantoms, and up to 2.8% in vivo (for TR = 2 s, slice gap = 0%). A reduction of CV was observed when increasing the gap up to 100% (0.36% in phantoms, and up to 1.5% in vivo) or increasing TR up to 4 s (0.76% in phantoms, and up to 1.9% in vivo). Matching the multi-slice experimental data with multi-slice dictionaries provided a reduced CV of 0.54% in phantoms and up to 2.3% in vivo. CONCLUSION: T2 values quantified from multi-slice MESE images using single-slice dictionaries are biased. A dedicated multi-slice EMC method providing the appropriate dictionaries can reduce the inter-slice T2 variation.

Accelerating the simulation of annual bifacial illumination of real photovoltaic systems with ray tracing.

Accurate modeling of bifacial illumination is critical to improve the prediction of the energy yield of bifacial solar systems. Monte Carlo ray tracing is the most powerful tool to accomplish this task. In this work, we accelerate Monte Carlo ray tracing of large solar systems by nearly 90%. Our model achieves root-mean-square error values of 7.9% and 37.2% for the front and rear irradiance compared against single-axis tracking field reference data, respectively. The rear irradiance modeling error decreases to 18.9% if suspected snow periods are excluded. Crucially, our full system simulations show that surrounding ground surfaces affect the rear irradiance deep into the system. Therefore, unit system simulations cannot necessarily ignore the influence of the perimeter of large installations to accurately estimate annual yield. Large-scale simulations involving high-performance supercomputing were necessary to investigate these effects accurately, calibrate our simplified models, and validate our results against experimental measurements.

Cataract Surgery in One-Eyed Patients: A Cohort Study of 100 Patients.

PURPOSE: To determine the course and outcomes of cataract surgery in one-eyed patients. METHODS: This retrospective cohort study was conducted at the University Hospital of Nice, France. All one-eyed patients who underwent cataract surgery in their functional eye between January 2014 and December 2018 were included. A one-eyed patient was defined as having a visual acuity (VA) ≤20/200 in the other eye. Data were collected from the medical records and included the sociodemographic factors, the past medical history, data from the preoperative and postoperative clinical examinations, the surgical course, and the visual outcomes. RESULTS: One hundred one-eyed patients with a mean age of 74.01 years were included (48 men/52 women). The mean preoperative VA was 20/100 (+0.74 logMAR). The VA ranged between 20/200 and 20/40 in 75 (75%) patients, was >20/40 in 8 (8%), and was <20/200 in 17 (17%) patients. Fifty-eight (58%) patients were operated on an outpatient basis. General or locoregional anesthesia was used in 29 (29%) and 9 (9%) patients, respectively. All cataract surgery procedures were performed by phacoemulsification. Five (5%) patients experienced intraoperative complications. Seventy-three (73%) one-eyed patients achieved a final VA ≥20/40. The mean final VA was 20/50 (+0.37 logMAR) (p < 0.001). CONCLUSION: A low rate of intraoperative complications was observed in one-eyed patients during cataract surgery. In most cases, a good visual recovery was achieved after cataract surgery, even in patients who experienced a surgical complication.

Cutaneous manifestations of COVID-19 in children (and adults): A virus that does not discriminate.

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a beta coronavirus with a characteristic S-glycoprotein spike on the cell surface. Initial reports did not include cutaneous manifestations as a feature of COVID-19; however, there is a growing repertoire of reports demonstrating an array of dermatologic manifestations on the skin in children and adults. Dermatologic afflictions have been summarized into different categories several times, with the most recent analysis identifying six clinical patterns: urticaria, maculopapular-morbilliform eruption, papulovesicular exanthem, chilblain-like acral pattern, livedo reticularis-livedo racemosa pattern, and purpuric vasculitic pattern. In children, the dermatologic features appear to occur before or concomitantly with other COVID-19 manifestations. Dermatologists play a key role in diagnosing patients with COVID-19 who may present for the first time unwittingly exhibiting early signs of COVID-19. We have reviewed the current evidence on the dermatologic impact of COVID-19 in both the adult and pediatric populations.

Clinical evaluation of the Abbott Alinity SARS-CoV-2 spike-specific quantitative IgG and IgM assays in infected, recovered, and vaccinated groups

The COVID-19 pandemic continues to impose a significant burden on global health infrastructure. While identification and containment of new cases remains important, laboratories must now pivot and consider assessment of SARS-CoV-2 immunity in the setting of the recent availability of multiple COVID-19 vaccines. Here we have utilized the latest Abbott Alinity semi-quantitative IgM and quantitative IgG spike protein (SP) serology assays (IgMSP and IgGSP) in combination with Abbott Alinity IgG nucleocapsid (NC) antibody test (IgGNC) to assess antibody responses in a cohort of 1236 unique participants comprised of naive, SARS-CoV-2 infected, and vaccinated (including both naive and recovered) individuals. The IgMSP and IgGSP assays were highly specific (100%) with no cross-reactivity to archived samples recovered prior to the emergence of SARS-CoV-2, including those from individuals with seasonal coronavirus infections. Clinical sensitivity was 96% after 15 days for both IgMSP and IgGSP assays individually. When considered together, the sensitivity was 100%. A combination of NC- and SP-specific serologic assays clearly differentiated naive, SARS-CoV-2-infected, and vaccine-related immune responses. Vaccination resulted in a significant increase in IgGSP and IgMSP titers, with a major rise in IgGSP following the booster (second) dose in the naive group. In contrast, SARS-CoV-2 recovered individuals had several fold higher IgGSP responses than naive following the primary dose, with a comparatively dampened response following the booster. This work illustrates the strong clinical performance of these new serological assays and their utility in evaluating and distinguishing serological responses to infection and vaccination.

Perception of quality of life in people experiencing or having experienced a Clostridioides difficile infection: a US population survey.

BACKGROUND: Although the incidence, severity and mortality of Clostridioides (Clostridium) difficile infection (CDI) have been increasing, patients' quality of life changes resulting from CDI have not been studied thoroughly. This study aimed at exploring the consequences of CDI on quality of life through patients' perspective. METHODS: An observational, cross-sectional study involving 350 participants with a self-reported CDI diagnosis was conducted through an online self-administered survey. Participants were grouped into those who had active disease ("Current CDI") and those who had a history of CDI ("Past CDI"). RESULTS: One hundred fifteen participants (33%) reported Current CDI and 235 (67%) reported Past CDI. A large majority of participants admitted that their daily activities were impacted by the infection (93.9% and 64.7% of Current and Past CDI respondents respectively, p < 0.05). Physical and psychological consequences of CDI were experienced by 63.5% and 66.1% of participants with active CDI. Despite the infection being cleared, these consequences were still frequently experienced in Past CDI cohort with similar rates (reported by 73.2% of respondents for both, physical consequences p = 0.08; psychological consequences p = 0.21). After the infection, 56.6% of respondents noted that post-CDI symptoms remained; 40.9% believed they would never get rid of them. CONCLUSIONS: While the societal burden of CDI is well described in the literature, our study is one of the first aimed at understanding the major burden of CDI on quality of life. Our results highlight the long-lasting nature of CDI and further reinforce the need for enhanced therapeutics in the prevention and treatment of this devastating infection.

Integration of Monte-Carlo ray tracing with a stochastic optimisation method: application to the design of solar receiver geometry.

A stochastic optimisation method adapted to illumination and radiative heat transfer problems involving Monte-Carlo ray-tracing is presented. A solar receiver shape optimisation case study illustrates the advantages of the method and its potential: efficient receivers are identified using a moderate computational cost.