Insight into the photocatalytic and photothermal effect in plasmon-enhanced water oxidation property of AuTNP@MnOx core-shell nanoconstruct.

The development of robust and efficient photocatalytic constructs for boosting the water oxidation reaction (WOR) is needed for establishing a sunlight-driven renewable energy infrastructure. Here, we synthesized plasmonic core-shell nanoconstructs consisting of triangular gold nanoprism (AuTNP) core with mixed manganese oxide (MnOx) shell for photoelectrocatalytic WOR. These constructs show electrocatalytic WOR with a low onset overpotential requirement of 270 mV at pH 10. Photoexcitation showed further enhancement of their catalytic activity resulting in ∼15% decrease of the onset overpotential requirement along with the generation of photocurrent density of up to 300 µA/cm2. We showed that such light-driven enhancement of AuTNP@MnOx dyad's catalytic activity toward the WOR process includes contributions from both photocatalytic (hot carriers driven) and photothermal effects with photothermal effect playing the major role for wavelength between 532 and 808 nm. The contribution from the photocatalytic effect is appreciable only for high-energy excitations near the interband region, while the photothermal effect largely dominates for lower energy excitations near the LSPR wavelengths of the dyad.

Pancreatic Trauma: Imaging Review and Management Update.

Traumatic injuries of the pancreas are uncommon and often difficult to diagnose owing to subtle imaging findings, confounding multiorgan injuries, and nonspecific clinical signs. Nonetheless, early diagnosis and treatment are critical, as delays increase morbidity and mortality. Imaging has a vital role in diagnosis and management. A high index of suspicion, as well as knowledge of the anatomy, mechanism of injury, injury grade, and role of available imaging modalities, is required for prompt accurate diagnosis. CT is the initial imaging modality of choice, although the severity of injury can be underestimated and assessment of the pancreatic duct is limited with this modality. The time from injury to definitive diagnosis and the treatment of potential pancreatic duct injury are the primary factors that determine outcome following pancreatic trauma. Disruption of the main pancreatic duct (MPD) is associated with higher rates of complications, such as abscess, fistula, and pseudoaneurysm, and is the primary cause of pancreatic injury-related mortality. Although CT findings can suggest pancreatic duct disruption according to the depth of parenchymal injury, MR cholangiopancreatography and endoscopic retrograde cholangiopancreatography facilitate direct assessment of the MPD. Management of traumatic pancreatic injury depends on multiple factors, including mechanism of injury, injury grade, presence (or absence) of vascular injury, hemodynamic status of the patient, and associated organ damage. ©RSNA, 2020 See discussion on this article by Patlas.

Synthesis of Solution-Stable End-to-End Linked Gold Nanorod Dimers via pH-Dependent Surface Reconfiguration.

End-to-end dimers of gold nanorods are predicted to be excellent substrates for surface-enhanced spectroscopy. However, the synthesis of solution-stable end-to-end dimers remains challenging. We exploit the pH-dependent configurational change of polyelectrolytes to initiate and terminate the gold nanorod assembly formation to produce end-to-end linked dimers in high yield. The gold nanorods are first overcoated with a polyelectrolyte, and the end-to-end attachment is initiated by adding a thiol linker in acidic medium. The assembly formation is then terminated at the dimer stage by changing the pH of the medium by the addition of an appropriate amount of 1,4-diazabicyclo[2.2.2]octane (DABCO).The nanorod dimers synthesized here are stable in solution for a week without any additional surface encapsulation.

Imaging of Renal Transplant Complications throughout the Life of the Allograft: Comprehensive Multimodality Review.

The kidney is the most commonly transplanted solid organ. Advances in surgical techniques, immunosuppression regimens, surveillance imaging, and histopathologic diagnosis of rejection have allowed prolonged graft survival times. However, the demand for kidneys continues to outgrow the available supply, and there are efforts to increase use of donor kidneys with moderate- or high-risk profiles. This highlights the importance of evaluating the renal transplant patient in the context of both donor and recipient risk factors. Radiologists play an integral role within the multidisciplinary team in care of the transplant patient at every stage of the transplant process. In the immediate postoperative period, duplex US is the modality of choice for evaluating the renal allograft. It is useful for establishing a baseline examination for comparison at future surveillance imaging. In the setting of allograft dysfunction, advanced imaging techniques including MRI or contrast-enhanced US may be useful for providing a more specific diagnosis and excluding nonrejection causes of renal dysfunction. When a pathologic diagnosis is deemed necessary to guide therapy, US-guided biopsy is a relatively low-risk, safe procedure. The range of complications of renal transplantation can be organized temporally in relation to the time since surgery and/or according to disease categories, including immunologic (rejection), surgical or iatrogenic, vascular, urinary, infectious, and neoplastic complications. The unique heterotopic location of the renal allograft in the iliac fossa predisposes it to a specific set of complications. As imaging features of infection or malignancy may be nonspecific, awareness of the patient's risk profile and time since transplantation can be used to assign the probability of a certain diagnosis and thus guide more specific diagnostic workup. It is critical to understand variations in vascular anatomy, surgical technique, and independent donor and recipient risk factors to make an accurate diagnosis and initiate appropriate treatment.©RSNA, 2019.

US of Right Upper Quadrant Pain in the Emergency Department: Diagnosing beyond Gallbladder and Biliary Disease.

Acute cholecystitis is the most common diagnosable cause for right upper quadrant abdominal (RUQ) pain in patients who present to the emergency department (ED). However, over one-third of patients initially thought to have acute cholecystitis actually have RUQ pain attributable to other causes. Ultrasonography (US) is the primary imaging modality of choice for initial imaging assessment and serves as a fast, cost-effective, and dynamic modality to provide a definitive diagnosis or a considerably narrowed list of differential possibilities. Multiple organ systems are included at standard RUQ US, and a variety of ultrasonographically diagnosable disease processes can be identified, including conditions of hepatic, pancreatic, adrenal, renal, gastrointestinal, vascular, and thoracic origin, all of which may result in RUQ pain. In certain cases, subsequent computed tomography, magnetic resonance (MR) imaging, MR cholangiopancreatography, or cholescintigraphy may be considered, depending on the clinical situation and US findings. Familiarity with the spectrum of disease processes outside of the gallbladder and biliary tree that may manifest with RUQ pain and recognition at US of these alternative conditions is pivotal for early diagnosis and appropriate management. Diagnosis at the time of initial US can reduce unnecessary imaging and its consequences, including excess cost, radiation exposure, nephrotoxic contrast medium use, and time to diagnosis, thereby translating into improved patient care and outcome. This article (a) reviews the causes of RUQ pain identifiable at US using an organ-system approach, (b) illustrates the US appearance of select conditions from each organ system with multimodality imaging correlates, and (c) discusses the relevant pathophysiology and treatment of these entities to aid in efficient direction of management. Online supplemental material is available for this article. ©RSNA, 2018.

Highly specific plasmonic biosensors for ultrasensitive microRNA detection in plasma from pancreatic cancer patients.

MicroRNAs (miRs) are small noncoding RNAs that regulate mRNA stability and/or translation. Because of their release into the circulation and their remarkable stability, miR levels in plasma and other biological fluids can serve as diagnostic and prognostic disease biomarkers. However, quantifying miRs in the circulation is challenging due to issues with sensitivity and specificity. This Letter describes for the first time the design and characterization of a regenerative, solid-state localized surface plasmon resonance (LSPR) sensor based on highly sensitive nanostructures (gold nanoprisms) that obviates the need for labels or amplification of the miRs. Our direct hybridization approach has enabled the detection of subfemtomolar concentration of miR-X (X = 21 and 10b) in human plasma in pancreatic cancer patients. Our LSPR-based measurements showed that the miR levels measured directly in patient plasma were at least 2-fold higher than following RNA extraction and quantification by reverse transcriptase-polymerase chain reaction. Through LSPR-based measurements we have shown nearly 4-fold higher concentrations of miR-10b than miR-21 in plasma of pancreatic cancer patients. We propose that our highly sensitive and selective detection approach for assaying miRs in plasma can be applied to many cancer types and disease states and should allow a rational approach for testing the utility of miRs as markers for early disease diagnosis and prognosis, which could allow for the design of effective individualized therapeutic approaches.

Ultrasensitive photoreversible molecular sensors of azobenzene-functionalized plasmonic nanoantennas.

This Letter describes an unprecedentedly large and photoreversible localized surface plasmon resonance (LSPR) wavelength shift caused by photoisomerization of azobenzenes attached to gold nanoprisms that act as nanoantennas. The blue light-induced cis to trans azobenzene conformational change occurs in the solid state and controls the optical properties of the nanoprisms shifting their LSPR peak up to 21 nm toward longer wavelengths. This shift is consistent with the increase in thickness of the local dielectric environment (0.6 nm) surrounding the nanoprism and perhaps a contribution from plasmonic energy transfer between the nanoprism and azobenzenes. The effects of the azobenzene conformational change and its photoreversibility were also probed through surface-enhanced Raman spectroscopy (SERS) showing that the electronic interaction between the nanoprisms and bound azobenzenes in their cis conformation significantly enhances the intensity of the Raman bands of the azobenzenes. The SERS data suggests that the isomerization is controlled by first-order kinetics with a rate constant of 1.0 × 10(-4) s(-1). Our demonstration of light-induced photoreversibility of this type of molecular machine is the first-step toward removing present limitations on detection of molecular motion in solid-state devices using LSPR spectroscopy with nanoprisms. Modulating the LSPR peak position and controlling energy transfer across the nanostructure-organic molecule interface are very important for the fabrication of plasmonic-based nanoscale devices.

Ligand-mediated electron transport channels enhance photocatalytic activity of plasmonic nanoparticles.

Photoexcitation of noble metal nanoparticles creates surface plasmons which further decay to form energetic charge carriers. These charge carriers can initiate and/or accelerate various chemical processes at nanoparticle surfaces, although the efficiency of such processes remains low as a large fraction of these carriers recombine before they can reach the reaction sites. Thus efficient utilization of these charge carriers requires designing nanostructures that promote the separation of charges and their transport toward the reaction sites. Here we demonstrate that covalently bound surface-coating ligands with suitable orbital alignment can provide electron transport channels boosting hot electron extraction from a gold nanostructure leading to a huge enhancement in the rate of hydrogen evolution reaction (HER) under NIR excitation. A (p)Br-Ph-SH substituted gold nanoprism (AuTP) substrate produced ∼4500 fold more hydrogen compared to a pristine AuTP substrate under 808 nm excitation. Further experimental and theoretical studies on a series of substituted benzene-thiol bound AuTP substrates showed that the extent of the ligand-mediated HER enhancement depends not only on the polarity of the ligand but on the interfacial orbitals interactions.

NIR-Driven Photocatalytic Hydrogen Production by Silane- and Tertiary Amine-Bound Plasmonic Gold Nanoprisms.

Near-infrared (NIR) photon-driven H2 production from water is regarded as one of the best routes for establishing a sustainable hydrogen-based energy economy. Here, we have developed a gold nanoprism-based photocatalytic assembly, rationally capped with an amine and a silane ligand pair, which exhibited an excellent H2 production rate (146 µL mg-1 h-1) in neutral water while achieving an absolute incident photon-to-hydrogen conversion efficiency of 0.53%. An array of spectroscopic and microscopic experiments unravel that the amine ligand scavenges the hot hole while the silane aids the H2 production via hydrolysis during the photocatalysis on the plasmon surface. This photocatalytic H2 production reactivity can be retained for multiple cycles following the replenishment of amine and silane. Hence, this photocatalytic assembly can set up the template for a large-scale NIR-driven H2 production unit.

Ballistic and Penetrating Injuries of the Chest.

Ballistic injuries are a major cause of morbidity and mortality in the United States. Unstable patients have high mortality, and only a small subset arrive at the hospital alive. Many patients undergo emergent surgery upon arrival, but a small subset undergo imaging with plain film, computed tomography, and echocardiography. We present a pictorial essay of ballistic and penetrating injuries and their complications with a focus on lung, cardiac, and vascular injury.

Remifentanil to facilitate high-resolution computed tomography imaging of the chest or magnetic resonance imaging in infants.

INTRODUCTION: High-resolution computed tomography (CT) imaging or magnetic resonance (MR) imaging may require brief periods of apnea for image acquisition. In adults, this may be done by voluntary breath holding. In infants and children, such studies are generally performed under general anesthesia using a laryngeal mask airway with maintenance of spontaneous ventilation. METHODS: We report a technique using the short-acting synthetic opioid, remifentanil, as part of an anesthetic technique to provide brief periods of apnea and the rapid resumption of spontaneous ventilation. RESULTS: The study cohort included 12 patients (8 for high-resolution CT imaging and 4 for abdominal MR imaging) who ranged in age from 6 to 16 months. General anesthesia with spontaneous ventilation was induced with sevoflurane in air and oxygen. When apnea was required, remifentanil (3 microg/kg) was administered. Apnea occurred within 30-60 seconds following the bolus dose of remifentanil (42 +/- 8 seconds). The duration of apnea varied from 3 to 8 minutes (4.8 +/- 1.5 minutes). Following the administration of remifentanil, there was a decrease in heart rate (HR) from 127 +/- 7 to a low of 108 +/- 9 beats per minute (P < 0.0001). Systolic blood pressure (sBP) decreased from 84 +/- 6 mm Hg to 78 +/- 5 mm Hg (P = 0.0071). One patient received a fluid bolus (10 mL/kg) for a sBP of 56 mm Hg. No other adverse effects were noted. CONCLUSIONS: This technique facilitated anesthetic care by allowing the use of a laryngeal mask airway (LMA) for both the radiologic imaging as well as bronchoscopy which was performed after the radiologic imaging. The use of a bolus dose of remifentanil provided a brief period of apnea for the acquisition of the radiologic images.

Ultrasound Evaluation in Patients at Risk for Hepatocellular Carcinoma.

In the context of chronic liver disease (CLD), sonographic features of hepatic steatosis, cirrhosis, and portal hypertension are discussed and examples are provided. The impact of CLD and hepatocellular carcinoma (HCC) is introduced, providing the rationale for a robust HCC screening and surveillance program for at-risk patients. The American College of Radiology Liver Imaging Reporting and Data System algorithms for screening and surveillance by ultrasound and for the definitive diagnosis of HCC by contrast-enhanced ultrasound are explained, with imaging examples provided. Contrast-enhanced ultrasound technique, limitations, and pitfalls also are introduced.

Heterotopic pancreatic rests: imaging features, complications, and unifying concepts.

OBJECTIVE: The spectrum of pancreatic heterotopia will be reviewed, including clinical features, potential complications, and imaging manifestations. This will also include a review of various entities associated with pancreatic heterotopia such as groove pancreatitis and cystic dystrophy of gastroduodenal heterotopic pancreas. These entities were previously thought of as distinct histopathologic entities but now appear to represent manifestations of pancreatic heterotopia. CONCLUSION: Pancreatic heterotopia and heterotopic pancreatitis can have a wide range of appearances. Several entities, which were previously thought to be distinct, can be considered manifestations of pancreatic heterotopia and heterotopic pancreatitis.

Label-Free Nanoplasmonic-Based Short Noncoding RNA Sensing at Attomolar Concentrations Allows for Quantitative and Highly Specific Assay of MicroRNA-10b in Biological Fluids and Circulating Exosomes.

MicroRNAs are short noncoding RNAs consisting of 18-25 nucleotides that target specific mRNA moieties for translational repression or degradation, thereby modulating numerous biological processes. Although microRNAs have the ability to behave like oncogenes or tumor suppressors in a cell-autonomous manner, their exact roles following release into the circulation are only now being unraveled and it is important to establish sensitive assays to measure their levels in different compartments in the circulation. Here, an ultrasensitive localized surface plasmon resonance (LSPR)-based microRNA sensor with single nucleotide specificity was developed using chemically synthesized gold nanoprisms attached onto a solid substrate with unprecedented long-term stability and reversibility. The sensor was used to specifically detect microRNA-10b at the attomolar (10(-18) M) concentration in pancreatic cancer cell lines, derived tissue culture media, human plasma, and media and plasma exosomes. In addition, for the first time, our label-free and nondestructive sensing technique was used to quantify microRNA-10b in highly purified exosomes isolated from patients with pancreatic cancer or chronic pancreatitis, and from normal controls. We show that microRNA-10b levels were significantly higher in plasma-derived exosomes from pancreatic ductal adenocarcinoma patients when compared with patients with chronic pancreatitis or normal controls. Our findings suggest that this unique technique can be used to design novel diagnostic strategies for pancreatic and other cancers based on the direct quantitative measurement of plasma and exosome microRNAs, and can be readily extended to other diseases with identifiable microRNA signatures.

Comparison of the effect of iterative reconstruction versus filtered back projection on cardiac CT postprocessing.

RATIONALE AND OBJECTIVES: To investigate the impact of iterative reconstruction in image space (IRIS) on image noise, image quality (IQ), and postprocessing at coronary computed tomography angiography (cCTA) compared to traditional filtered back-projection (FBP). MATERIALS AND METHODS: The cCTA results of 50 patients (26 men; 58 ± 15 years, body mass index 31.5 ± 6.7 kg/m²) were investigated using a second-generation dual-source computed tomography system. Scan data were reconstructed with the use of IRIS and FBP algorithms. Two radiologists independently evaluated the reconstructions using automated coronary tree analysis software. Image noise was measured and IQ was rated on a 5-point Likert scale. The number of manual corrections after automated vessel segmentation, the time required to complete segmentation, and the number of missed segments were assessed in both IRIS and FBP reconstructions. Results were compared using paired t-test. RESULTS: IRIS significantly reduced image noise compared to FBP (23.3 ± 8.8 vs. 33.5 ± 13.5 Hounsfield units, P < .001). Subjective IQ improved with IRIS (IRIS 3.2 ± 1.0 vs. FBP 3.0 ± 1.0, P < .05). IRIS decreased the time needed for coronary segmentation from 111.9 ± 40.5 seconds to 95.2 ± 38.2 seconds with FBP (P < .01) and required fewer manual corrections (5.7 ± 3.0 vs. 6.8 ± 3.6, P < .01). The number of missed vessel segments was not significantly different (3.6 ± 1.8 vs. 3.8 ± 1.9, P > .05) between IRIS and FBP, respectively. CONCLUSIONS: During cCTA postprocessing, IRIS significantly decreases the time and the number of manual corrections for a complete coronary segmentation compared to FBP. This effect is likely attributable to suppression of image noise by IRIS, which improves the performance of automated vessel segmentation and positively impacts cCTA analysis.

A five-year experience with the use of BiPAP in a pediatric intensive care unit population.

The authors retrospectively reviewed their experience with bilevel positive airway pressure (BiPAP) to treat respiratory insufficiency in pediatric patients over a 5-year period. After excluding patients on chronic home BiPAP and those in whom BiPAP was used to facilitate tracheal extubation (because there were no pre-BiPAP values on which to judge its efficacy), the study cohort included 45 patients (1.5 to 22 years) in whom BiPAP was used for acute respiratory insufficiency. The primary indication for BiPAP was a primary pulmonary parenchymal process in 29 patients and postoperative atelectasis with respiratory insufficiency following cardiac or upper abdominal surgery in 16 patients. There were no differences in the pre-BiPAP values of oxygen requirement, PCO2, oxygen saturation, and respiratory rate between the 2 groups. With the application of BiPAP in patients with primary pulmonary parenchymal disease, there was a decreased oxygen requirement, PCO2, and respiratory rate. No change in oxygen saturation was noted. In patients with postoperative respiratory insufficiency, there was an improvement in all 4 parameters. There was no difference in post-BiPAP values of oxygen requirement, respiratory rate, or PCO2 between the 2 groups. The post-BiPAP oxygen saturation was greater in patients with postoperative respiratory insufficiency (96% +/- 4%) than in patients with primary pulmonary parenchymal disease (92% +/- 6%, P = .02). Endotracheal intubation was required in 11 of 29 patients with primary pulmonary parenchymal pathology versus 1 of 16 patients with postoperative atelectasis and/or respiratory insufficiency (P = .03). The chances of requiring intubation were greater in patients < or = 6 years of age (relative risk 1.9), if the oxygen requirement did not decrease to less than 60% within the first 24 hours of BiPAP use (relative risk 3.3) and if there were any PCO2 values > or = 55 mmHg during the first 24 hours of BiPAP use (relative risk 9.8). No severe complications to BiPAP were noted. BiPAP safely and effectively improves the respiratory status of and might decrease the need for endotracheal intubation in pediatric patients with acute respiratory insufficiency of various etiologies.

Intentional use of intra-arterial medications when venous access is not available.

The difficult or impossible establishment of venous access is occasionally encountered in the pediatric population, especially in patients exposed to repeated surgical procedures or those with underlying comorbid features. Potential options in such situations include the intramuscular, intraosseous (IO), and intratracheal administration of medications. Although IO access is accepted as the route of choice in emergency situations, its use is not universally accepted in the operating room setting when the administration of medications is nonemergent. We report the intentional and elective use of the intra-arterial (IA) administration of vecuronium, atropine, fentanyl, and fluid during the provision of anesthesia for two infants with severe cyanotic congenital heart disease in whom venous access could not readily be obtained. The potential role of IA administration of medications is discussed and previous reports from the literature are reviewed.