Life-Threatening Hematuria as Initial Presentation of a Complicated Transplant Renal Artery Pseudoaneurysm.

In this case report, we describe the clinical course of a complicated transplant renal artery (TRA) pseudoaneurysm, clinically featured by gross and massive hematuria one month after a kidney transplant was performed on a 50 year-old male patient. TRA pseudoaneurysm is a rare but potentially life-threatening complication that may result in bleeding, infection, graft dysfunction/loss, lower limb ischemia/loss, hemorrhagic shock, and death. TRA pseudoaneurysm treatment remains challenging as it needs to be tailored to the patient characteristics including hemodynamic stability, graft function, anatomy, presentation, and pseudoaneurysm features. This publication discusses the clinical scenario of massive gross hematuria that derived from a retroperitoneal hematoma which originated from an actively bleeding TRA pseudoaneurysm. This case highlights the combined approach of endovascular stent placement and subsequent transplant nephrectomy as a last resort in the management of intractable bleeding from a complicated TRA pseudoaneurysm. To the best of our knowledge, this is the first published case report of an actively bleeding TRA anastomotic pseudoaneurysm that caused a massive retroperitoneal bleed that in turn evacuated via the bladder after disrupting the ureter-to-bladder anastomosis. A temporizing hemostatic arterial stent placed percutaneously allowed for a safer and controlled emergency transplant nephrectomy.

Metal-Air Field Emission Devices - Nano Electrode Geometries Comparison of Performance and Stability.

Air-channel devices have a special advantage due to the promise of vacuum-like ballistic transport in air, radiation insensitivity, and nanoscale size. Here, achieving high current at low voltage along with considerable mechanical stability is a primary issue. The comparative analysis of four planar and metallic electrode-pair geometries at 10 nm channel length is presented. The impact of nano-electrode-pair geometries on overall device performance is investigated. Air-channel devices are operated at the ultra-low voltage of 5 mV to demonstrate the device dynamics of air-channel devices at low power. Investigations focus on the direct tunneling (DT) mechanism which is dominant in the low-voltage regime. Comparative analysis of different electrode-pair geometries reveals two orders of magnitude increment in the current just by modulating the electrode-pair structure. Theoretical analysis suggests that the emission current is directly related to the active junction area within the metal-air-metal interface at the direct tunneling regime. The geometry-dependent mechanical stability of different electrode pairs is compared by imaging biasing triggered nanoscale structural changes and pulsed biasing stress analysis. The results and claims are confirmed and consolidated with the statistical analysis. Experimental investigations provide strong directions for high-performance and stable devices. In-depth theoretical discussions will enable the accurate modeling of emerging low-power, high-speed, radiation-hardened nanoscale vacuum electronics.

Principles of Virtual Crossmatch Testing for Kidney Transplantation.

Human leukocyte antigens (HLAs) are the primary determinants of alloimmunity. A crossmatch test is a test that determines the immunologic risk of a recipient with a potential donor by ensuring that there are no transplant-relevant circulating antibodies in the recipient directed against donor antigens. Physical crossmatch (PXM) tests, such as complement-dependent cytotoxicity crossmatch (CDCXM) and flow cytometry crossmatch (FCXM), require mixing of patient serum and donor cells, are labor intensive, and are logistically challenging. Virtual crossmatch (VXM) test assesses immunologic compatibility between recipient and potential donor by analyzing the results of 2 independently done physical laboratory tests-patient anti-HLA antibody and donor HLA typing. The goal of VXM is pretransplant risk stratification-though there is no consensus on whether such risk assessment involves predicting the PXM result or the posttransplant outcome. Although the concept of VXM is not new, the advent of solid-phase assays for detecting circulating antibodies in the recipient directed against individual HLA and DNA-based methods for typing donor HLA specificities at a higher resolution makes the routine use of VXM a reality. Accordingly, VXM may be applied at different scenarios-both for sensitized and nonsensitized patients. Implementation of VXM-based approach has resulted in statistically significant reduction in cold ischemia time without an increase in hyperacute rejection episodes. Though there are considerable challenges, VXM is expected to be used more often in the future, depending on the transplant center's tolerance of immunologic risk.

The effect of race coefficients on preemptive listing for kidney transplantation.

Background: Race coefficients of estimated glomerular filtration rate (eGFR) formulas may be partially responsible for racial inequality in preemptive listing for kidney transplantation. Methods: We used the Scientific Registry of Transplant Recipients database to evaluate differences in racial distribution of preemptive listing before and after application of the Modification of Diet in Renal Disease (MDRD) and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) race coefficients to all preemptively listed non-Black kidney transplant candidates (eGFR modulation). Odds of preemptive listing were calculated by race, with Black as the reference before and after eGFR modulation. Variables known to influence preemptive listing were included in the model. Results: Among 385 087 kidney-alone transplant candidates from 1 January 2010 to 2 December 2020, 118 329 (30.7%) candidates were identified as preemptively listed (71.7% White, 19% Black, 7.8% Asian, 0.6% multi-racial, 0.6% Native American and 0.3% Pacific Islander). After eGFR modulation, non-Black patients with an eGFR ≥20 mL/min/1.73 m2 were removed. Compared with Black candidates, the adjusted odds of preemptive listing for White candidates decreased from 2.01 [95% confidence interval (95% CI) 1.78-2.26] before eGFR modulation to 1.18 (95% CI 1.0-1.39; P = 0.046) with the MDRD and 1.37 (95% CI 1.18-1.58) with the CKD-EPI equations after adjusting for race coefficients. Conclusions: Removing race coefficients in GFR estimation formulas may result in a more equitable distribution of Black candidates listed earlier on a preemptive basis.

COVID-19 in an Asymptomatic Renal Transplant Recipient Employed in the Health Care Setting: A Case Report.

During the ongoing pandemic, there have been varying presentations of coronavirus disease 2019 (COVID-19) infection, with the concern that patients who are immunosuppressed (due to underlying medical conditions and/or therapies) are at higher risk of severe disease. We report the case of an elderly renal transplant recipient working in a long-term health care facility who was being monitored by weekly surveillance testing and tested positive for COVID-19 by polymerase chain reaction (PCR) testing, despite having no clinical symptoms. He recovered with supportive care, despite being on multiple long-term immunosuppressant drugs and having multiple comorbidities. Additionally, it was found that he did not mount an antibody response, when he tested negative by serologic testing. Through this case, we wish to highlight the unique clinical scenario of asymptomatic patients who may have an underwhelming immune response to COVID-19, but may nevertheless be an important source of dissemination. We further discuss the probable mechanism of such asymptomatic presentations in immunosuppressed patients, while reinforcing the importance of self-isolation of COVID-19 patients (particularly in asymptomatic health care workers).

Nicotine Sensors for Wearable Battery-Free Monitoring of Vaping.

Nicotine, an addictive substance in tobacco products and electronic cigarettes (e-cigs), is recognized for increasing the risk of cardiovascular and respiratory disorders. Careful real-time monitoring of nicotine exposure is critical in alleviating the potential health impacts of not just smokers but also those exposed to second-hand and third-hand smoke. Monitoring of nicotine requires suitable sensing material to detect nicotine selectively and testing under free-living conditions in the standard environment. Here, we experimentally demonstrate a vanadium dioxide (VO2)-based nicotine sensor and explain its conductometric mechanisms with compositional analysis and density functional theory (DFT) calculations. For real-time monitoring of nicotine vapor from e-cigarettes in the air, the sensor is integrated with an epidermal near-field communication (NFC) interface that enables battery-free operation and data transmission to smart electronic devices to record and store sensor data. Collectively, the technique of sensor development and integration expands the use of wearable electronics for real-time monitoring of hazardous elements in the environment and biosignals wirelessly.

Rapid Conductometric Detection of SARS-CoV-2 Proteins and Its Variants Using Molecularly Imprinted Polymer Nanoparticles.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) biosensors have captured more attention than the conventional methodologies for SARS-CoV-2 detection due to having cost-effective platforms and fast detection. However, these reported SARS-CoV-2 biosensors suffer from drawbacks including issues in detection sensitivity, degradation of biomaterials on the sensor's surface, and incapability to reuse the biosensors. To overcome these shortcomings, molecularly imprinted polymer nanoparticles (nanoMIPs) incorporated conductometric biosensor for highly accurate, rapid, and selective detection of two model SARS-CoV-2 proteins: (i) receptor binding domain (RBD) of the spike (S) glycoprotein and (ii) full length trimeric spike protein are introduced. In addition, these biosensors successfully responded to several other SARS-CoV-2 RBD spike protein variants including Alpha, Beta, Gamma, and Delta. Our conductometric biosensor selectively detects the two model proteins and SARS-CoV-2 RBD spike protein variant samples in real-time with sensitivity to a detection limit of 7 pg mL-1 within 10 min of sample incubation. A battery-free, wireless near-field communication (NFC) interface is incorporated with the biosensor for fast and contactless detection of SARS-CoV-2 variants. The smartphone enabled real-time detection and on-screen rapid result for SARS-CoV-2 variants can curve the outbreak due to its ability to alert the user to infection in real time.

Terahertz transmissive half-wave metasurface with enhanced bandwidth: publisher's note.

This publisher's note contains corrections to Opt. Lett.46, 4164 (2021)OPLEDP0146-959210.1364/OL.431285.

Terahertz transmissive half-wave metasurface with enhanced bandwidth.

Polarization conversion is useful for studies of chiral structures in biology and chemistry, and for polarization diversity in communications. It is conventionally realized with wave plates, which, however, present challenges due to limited material availability, as well as narrow bandwidth and low efficiency at terahertz frequencies. To enhance bandwidth and efficiency, the concept of the Huygens' metasurface is adopted here for a transmissive half-wave plate. The half-wave metasurface is designed following the optimal frequency-independent circuit parameters provided by a broadband semi-analytical approach. Simulation results of an optimal design suggest that a 15-dB extinction ratio can be sustained from 219 GHz to 334 GHz, corresponding to a fractional bandwidth of 41.6%. The measured results indicate that the fabricated structure enables a 15-dB extinction ratio from 220 GHz to 303 GHz, with a cross-polarization transmission efficiency above 76.7% for both linear and circular polarizations. This half-wave metasurface design can be readily integrated into compact terahertz systems for diverse applications.

UV Photochromism in Transition Metal Oxides and Hybrid Materials.

Limited levels of UV exposure can be beneficial to the human body. However, the UV radiation present in the atmosphere can be damaging if levels of exposure exceed safe limits which depend on the individual the skin color. Hence, UV photochromic materials that respond to UV light by changing their color are powerful tools to sense radiation safety limits. Photochromic materials comprise either organic materials, inorganic transition metal oxides, or a hybrid combination of both. The photochromic behavior largely relies on charge transfer mechanisms and electronic band structures. These factors can be influenced by the structure and morphology, fabrication, composition, hybridization, and preparation of the photochromic materials, among others. Significant challenges are involved in realizing rapid photochromic change, which is repeatable, reversible with low fatigue, and behaving according to the desired application requirements. These challenges also relate to finding the right synergy between the photochromic materials used, the environment it is being used for, and the objectives that need to be achieved. In this review, the principles and applications of photochromic processes for transition metal oxides and hybrid materials, photocatalytic applications, and the outlook in the context of commercialized sensors in this field are presented.

Active Control of Nanodielectric-Induced THz Quasi-BIC in Flexible Metasurfaces: A Platform for Modulation and Sensing.

A bound state in the continuum (BIC) is a nonradiating state of light embedded in the continuum of propagating modes providing drastic enhancement of the electromagnetic field and its localization at micro-nanoscale. However, access to such modes in the far-field requires symmetry breaking. Here, it is demonstrated that a nanometric dielectric or semiconductor layer, 1000 times thinner than the resonant wavelength (λ/1000), induces a dynamically controllable quasi-bound state in the continuum (QBIC) with ultrahigh quality factor in a symmetric metallic metasurface at terahertz frequencies. Photoexcitation of nanostrips of germanium activates ultrafast switching of a QBIC resonance with 200% transmission intensity modulation and complete recovery within 7 ps on a low-loss flexible substrate. The nanostrips also form microchannels that provide an opportunity for BIC-based refractive index sensing. An optimization model is presented for (switchable) QBIC resonances of metamaterial arrays of planar symmetric resonators modified with any (active) dielectric for inverse metamaterial design that can serve as an enabling platform for active micro-nanophotonic devices.

Non-alcoholic fatty liver and chronic kidney disease: Retrospect, introspect, and prospect.

With the growing prevalence of obesity and diabetes in the United States and across the world, a rise in the overall incidence and prevalence of non-alcoholic fatty liver disease (NAFLD) is expected. The risk factors for NAFLD are also associated with the development of chronic kidney disease (CKD). We review the epidemiology, risk factors, genetics, implications of gut dysbiosis, and specific pathogenic mechanisms linking NAFLD to CKD. Mechanisms such as ectopic lipid accumulation, cellular signaling abnormalities, and the interplay between fructose consumption and uric acid accumulation have led to the emergence of potential therapeutic implications for this patient population. Transplant evaluation in the setting of both NAFLD and CKD is also reviewed. Potential strategies for surveillance and management include the monitoring of comorbidities, the use of non-invasive fibrosis scoring systems, and the measurement of laboratory markers. Lastly, we discuss the management of patients with NAFLD and CKD, from preventative measures to experimental interventions.

An early experience on the effect of solid organ transplant status on hospitalized COVID-19 patients.

We compared the outcome of COVID-19 in immunosuppressed solid organ transplant (SOT) patients to a transplant naïve population. In total, 10 356 adult hospital admissions for COVID-19 from March 1, 2020 to April 27, 2020 were analyzed. Data were collected on demographics, baseline clinical conditions, medications, immunosuppression, and COVID-19 course. Primary outcome was combined death or mechanical ventilation. We assessed the association between primary outcome and prognostic variables using bivariate and multivariate regression models. We also compared the primary endpoint in SOT patients to an age, gender, and comorbidity-matched control group. Bivariate analysis found transplant status, age, gender, race/ethnicity, body mass index, diabetes, hypertension, cardiovascular disease, COPD, and GFR <60 mL/min/1.73 m2 to be significant predictors of combined death or mechanical ventilation. After multivariate logistic regression analysis, SOT status had a trend toward significance (odds ratio [OR] 1.29; 95% CI 0.99-1.69, p = .06). Compared to an age, gender, and comorbidity-matched control group, SOT patients had a higher combined risk of death or mechanical ventilation (OR 1.34; 95% CI 1.03-1.74, p = .027).

Rapid and Selective Biomarker Detection with Conductometric Sensors.

The biomarker detection in human body fluids is crucial as biomarkers are important in diagnosing diseases. Conventional invasive techniques for biomarker detection are associated with infection, tissue damage, and discomfort. Non-invasive devices are an attractive alternative. Here, metal oxide (oxygen-deficient zinc oxide, ZnO) based conductometric sensors with two-terminal electrodes for rapid detection of biomarkers in real-time, are presented. This platform can be engineered for non-invasive, sensitive, and on-demand selective detection of biomarkers based on surface functionalization. The three novelties in this biosensing technique include an on-demand target selection device platform, short (<10 min) incubation times, and real-time monitoring of the biomarker of interest by electrical (resistance change) measurements. Cardiac inflammatory biomarkers interleukin 6 (IL-6) and C-reactive protein (CRP) are used as the model antigens. The devices can detect 100× lower concentration of IL-6 than healthy levels in human saliva and sweat and 1000× and ≈50× lower CRP concentrations than healthy levels in human saliva and sweat, respectively. The devices show high selectivity for IL-6 and CRP antigens when tested with a mixture of biomarkers. This sensor platform can be extended to selective measurements for viruses or DNA screening, which enables a new category of compact and rapid point-of-care medical devices.

Hepatitis C-positive donor to negative recipient kidney transplantation: A real-world experience.

BACKGROUND: Several studies have shown that transplanting a hepatitis C virus (HCV)-negative recipients with a HCV-positive donor is feasible in a research setting. In February 2018, we began transplanting HCV-negative recipients with HCV-positive donors as standard of care. METHODS: All patients, except those with previously cured HCV and those with cirrhosis, were consented for HCV NAT-positive donor kidneys. After transplantation, patients were tested for HCV RNA until viremic. A direct-acting antiviral (DAA) agent was prescribed based on genotype and insurance approval. Sustained virologic response (SVR) at weeks 4 and 12 was recorded. Renal function and death censored graft survival at 1 year were evaluated and compared to recipients of HCV NAT-negative kidneys. RESULTS: A total of 25 HCV NAT-positive donor kidney transplants from February to October 2018 were performed. All patients received basiliximab and maintained with tacrolimus, mycophenolate mofetil, and prednisone. Median time from viremia to start of DAA was 13 (8-22) days. The most common genotype was 1a (60%), followed by 3a (28%). The most commonly prescribed DAA was ledipasvir/sofosbuvir (56%), followed by velpatasvir/sofosbuvir (32%), and then glecaprevir/pibrentasvir (12%). All patients achieved initial SVR12, except one. One patient had a mixed-genotype infection requiring retreatment to achieve SVR12. Death censored graft survival was 96%. Recipients of HCV NAT-positive organs compared to HCV NAT-negative organs received younger donors (mean 35 ± 8.9 vs 45.1 ± 15.7 years; P < .01) and spent less time on the waitlist (median 479 (93-582) vs 1808 (567-2263) days; P = .02). CONCLUSION: HCV NAT-negative recipients can be safely and successfully transplanted with HCV NAT-positive donor kidneys outside of a research protocol. Access to DAA and timely administration of therapy is important and an insurance approval process within the transplant center can be beneficial to patients. A case of mixed-genotype infection was presented, and although not as common, can be successfully treated. HCV organs can expand the organ pool and should no longer be considered experimental. The use of these organs in HCV-negative recipient's decreases waiting time, have excellent outcomes, and should be considered standard of care.

Fully Light-Controlled Memory and Neuromorphic Computation in Layered Black Phosphorus.

Imprinting vision as memory is a core attribute of human cognitive learning. Fundamental to artificial intelligence systems are bioinspired neuromorphic vision components for the visible and invisible segments of the electromagnetic spectrum. Realization of a single imaging unit with a combination of in-built memory and signal processing capability is imperative to deploy efficient brain-like vision systems. However, the lack of a platform that can be fully controlled by light without the need to apply alternating polarity electric signals has hampered this technological advance. Here, a neuromorphic imaging element based on a fully light-modulated 2D semiconductor in a simple reconfigurable phototransistor structure is presented. This standalone device exhibits inherent characteristics that enable neuromorphic image pre-processing and recognition. Fundamentally, the unique photoresponse induced by oxidation-related defects in 2D black phosphorus (BP) is exploited to achieve visual memory, wavelength-selective multibit programming, and erasing functions, which allow in-pixel image pre-processing. Furthermore, all-optically driven neuromorphic computation is demonstrated by machine learning to classify numbers and recognize images with an accuracy of over 90%. The devices provide a promising approach toward neurorobotics, human-machine interaction technologies, and scalable bionic systems with visual data storage/buffering and processing.

Cytomegalovirus Viremia in Renal Transplant Recipients After Influenza Vaccination.

Vaccination with the inactivated influenza vaccine is routinely recommended for all patients before and after transplant, with reduction in complications noted in transplant recipients. The vaccine is relatively well tolerated with few mild side effects. Cytomegalovirus (CMV) infection can reactivate in both solid organ transplant and hematopoietic stem cell transplant recipients, with some patients progressing to disease. There are multiple factors known to contribute to reactivation and subsequent CMV disease, however vaccination has not been reported as a specific risk factor. We report on two renal transplant recipients who were seen to develop CMV viremia and CMV disease after receiving the Influenza vaccine. We review the literature regarding viremia occurring after vaccination in HIV patients (a similar group of immunocompromised patients).

COVID-19 in kidney transplant recipients.

There is minimal information on coronavirus disease 2019 (COVID-19) in immunocompromised individuals. We have studied 10 patients treated at 12 adult care hospitals. Ten kidney transplant recipients tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by polymerase chain reaction, and 9 were admitted. The median age was 57 (interquartile range [IQR] 47-67), 60% were male, 40% Caucasian, and 30% Black/African American. Median time from transplant to COVID-19 testing was 2822 days (IQR 1272-4592). The most common symptom was fever, followed by cough, myalgia, chills, and fatigue. The most common chest X-ray and computed tomography abnormality was multifocal patchy opacities. Three patients had no abnormal findings. Leukopenia was seen in 20% of patients, and allograft function was stable in 50% of patients. Nine patients were on tacrolimus and a mycophenolic antimetabolite, and 70% were on prednisone. Hospitalized patients had their antimetabolite agent stopped. All hospitalized patients received hydroxychloroquine and azithromycin. Three patients died (30%), and 5 (50%) developed acute kidney injury. Kidney transplant recipients infected with COVID-19 should be monitored closely in the setting of lowered immunosuppression. Most individuals required hospitalization and presenting symptoms were similar to those of nontransplant individuals.

Electrically Activated UV-A Filters Based on Electrochromic MoO3-x.

Chromism-based optical filters is a niche field of research, due to there being only a handful of electrochromic materials. Typically, electrochromic transition metal oxides such as MoO3 and WO3 are utilized in applications such as smart windows and electrochromic devices (ECD). Herein, we report MoO3-x-based electrically activated ultraviolet (UV) filters. The MoO3-x grown on indium tin oxide (ITO) substrate is mechanically assembled onto an electrically activated proton exchange membrane. Reversible H+ injection/extraction in MoO3-x is employed to switch the optical transmittance, enabling an electrically activated optical filter. The devices exhibit broadband transmission modulation (325-800 nm), with a peak of ∼60% in the UV-A range (350-392 nm). Comparable switching times of 8 s and a coloration efficiency of up to 116 cm2 C-1 are achieved.