Two-Step Conversion of Metal and Metal Oxide Precursor Films to 2D Transition Metal Dichalcogenides and Heterostructures.

The widely studied class of two-dimensional (2D) materials known as transition metal dichalcogenides (TMDs) are now well-poised to be employed in real-world applications ranging from electronic logic and memory devices to gas and biological sensors. Several scalable thin film synthesis techniques have demonstrated nanoscale control of TMD material thickness, morphology, structure, and chemistry and correlated these properties with high-performing, application-specific device metrics. In this review, the particularly versatile two-step conversion (2SC) method of TMD film synthesis is highlighted. The 2SC technique relies on deposition of a solid metal or metal oxide precursor material, followed by a reaction with a chalcogen vapor at an elevated temperature, converting the precursor film to a crystalline TMD. Herein, the variables at each step of the 2SC process including the impact of the precursor film material and deposition technique, the influence of gas composition and temperature during conversion, as well as other factors controlling high-quality 2D TMD synthesis are considered. The specific advantages of the 2SC approach including deposition on diverse substrates, low-temperature processing, orientation control, and heterostructure synthesis, among others, are featured. Finally, emergent opportunities that take advantage of the 2SC approach are discussed to include next-generation electronics, sensing, and optoelectronic devices, as well as catalysis for energy-related applications.

M1 Macrophage-Induced Endothelial-to-Mesenchymal Transition Promotes Infantile Hemangioma Regression.

Infantile hemangiomas are benign tumors of vascular endothelial cells (ECs), characterized by three distinct stages: proliferating phase, involuting phase, and involuted phase. The mechanisms that trigger involution of hemangioma into fibro-fatty tissue remain unknown. We report a novel mechanism by which M1-polarized macrophages induce endothelial-to-mesenchymal transition (EndMT) and promote hemangioma regression. M1- but not M2-polarized macrophages induced EndMT in ECs. Tumor necrosis factor-α and, to a lesser extent, IL-1ß and interferon-γ were the most potent cytokines produced by the M1 macrophages that induce in vitro EndMT. Western blot analysis and gene expression profiling showed that ECs treated with M1 macrophages, tumor necrosis factor-α, or IL-1ß decreased the expression of endothelial markers, whereas mesenchymal markers increased concomitantly. Immunohistochemical staining of patient samples revealed that a significant perivascular infiltration of M1, but not M2, macrophages coincides with endothelial expression of the critical EndMT transcription factors Snail/Slug in involuting hemangiomas. Most strikingly, M1 macrophage-treated ECs isolated from patient hemangiomas (HemECs) but not untreated HemECs readily differentiated into adipocytes on adipogenic induction. Thus, in vitro EndMT and adipogenesis of HemECs have, in part, recapitulated the natural history of hemangioma regression. In conclusion, our findings indicate that EndMT induced by M1 macrophages promotes infantile hemangioma regression and may lead to novel therapeutic treatments for this vascular tumor.

Extracorporeal life support in critically ill adults.

Extracorporeal life support (ECLS) has become increasingly popular as a salvage strategy for critically ill adults. Major advances in technology and the severe acute respiratory distress syndrome that characterized the 2009 influenza A(H1N1) pandemic have stimulated renewed interest in the use of venovenous extracorporeal membrane oxygenation (ECMO) and extracorporeal carbon dioxide removal to support the respiratory system. Theoretical advantages of ECLS for respiratory failure include the ability to rest the lungs by avoiding injurious mechanical ventilator settings and the potential to facilitate early mobilization, which may be advantageous for bridging to recovery or to lung transplantation. The use of venoarterial ECMO has been expanded and applied to critically ill adults with hemodynamic compromise from a variety of etiologies, beyond postcardiotomy failure. Although technology and general care of the ECLS patient have evolved, ECLS is not without potentially serious complications and remains unproven as a treatment modality. The therapy is now being tested in clinical trials, although numerous questions remain about the application of ECLS and its impact on outcomes in critically ill adults.

Iatrogenic Preterm Premature Rupture of Membranes after Fetoscopic Laser Ablative Surgery.

INTRODUCTION: To describe the incidence and risk factors for iatrogenic premature preterm rupture of membranes (iPPROM) after fetoscopic laser surgery for the twin-to-twin-transfusion syndrome. MATERIALS AND METHODS: This is a retrospective review of all patients who have undergone fetoscopic laser surgery at a single fetal treatment center since 2000. We defined iPPROM as spontaneous rupture of membranes before the onset of labor prior to 34 weeks of gestation. The iPPROM cohort was compared to the cohort without iPPROM for several preoperative, operative, and delivery characteristics. RESULTS: Ninety-two consecutive patients were reviewed. The overall rate of iPPROM was 18.5% (n = 17). The rates of iPPROM within 1 and 4 weeks were 5.4 and 10.9%, respectively. The median interval from surgery to delivery was significantly shorter in the iPPROM group (21 vs. 62 days, p = 0.01). The mean gestational age at delivery (27.0 vs. 31.1 weeks, p = 0.02) was lower in the iPPROM group. No other characteristics studied differed significantly between the groups. DISCUSSION: The incidence of iPPROM was substantially lower than in recent multicenter reports; however, no risk factors of iPPROM could be identified. Whether this is related to variations in surgical or anesthetic management will require further investigation.

Nanoscale Adhesion and Material Transfer at 2D MoS2-MoS2 Interfaces Elucidated by In Situ Transmission Electron Microscopy and Atomistic Simulations.

Low-dimensional materials, such as MoS2, hold promise for use in a host of emerging applications, including flexible, wearable sensors due to their unique electrical, thermal, optical, mechanical, and tribological properties. The implementation of such devices requires an understanding of adhesive phenomena at the interfaces between these materials. Here, we describe combined nanoscale in situ transmission electron microscopy (TEM)/atomic force microscopy (AFM) experiments and simulations measuring the work of adhesion (Wadh) between self-mated contacts of ultrathin nominally amorphous and nanocrystalline MoS2 films deposited on Si scanning probe tips. A customized TEM/AFM nanoindenter permitted high-resolution imaging and force measurements in situ. The Wadh values for nanocrystalline and nominally amorphous MoS2 were 604 ± 323 mJ/m2 and 932 ± 647 mJ/m2, respectively, significantly higher than previously reported values for mechanically exfoliated MoS2 single crystals. Closely matched molecular dynamics (MD) simulations show that these high values can be explained by bonding between the opposing surfaces at defects such as grain boundaries. Simulations show that as grain size decreases, the number of bonds formed, the Wadh and its variability all increase, further supporting that interfacial covalent bond formation causes high adhesion. In some cases, sliding between delaminated MoS2 flakes during separation is observed, which further increases the Wadh and the range of adhesive interaction. These results indicate that for low adhesion, the MoS2 grains should be large relative to the contact area to limit the opportunity for bonding, whereas small grains may be beneficial, where high adhesion is needed to prevent device delamination in flexible systems.

Orientation and morphology control in acid-catalyzed covalent organic framework thin films.

As thin films of semiconducting covalent organic frameworks (COFs) are demonstrating utility for ambipolar electronics, channel materials in organic electrochemical transistors (OECTs), and broadband photodetectors, control and modulation of their thin film properties is paramount. In this work, an interfacial growth technique is utilized to synthesize imine TAPB-PDA COF films at both the liquid-liquid interface as well as at the liquid-solid interface on a Si/SiO2 substrate. The concentration of acetic acid catalyst in the aqueous phase is shown to significantly influence the thin film morphology of the liquid-solid growth, with concentrations below 1 M resulting in no film nucleation, concentrations of 1-4 M enabling smooth film formation, and concentrations greater than 4 M resulting in films with a higher density of particulates on the surface. Importantly, while the films grown at the liquid-liquid interface are mixed-orientation, those grown directly at the liquid-solid interface on the Si/SiO2 surface have highly oriented COF layers aligned parallel to the substrate surface. Moreover, this liquid-solid growth process affords TAPB-PDA COF thin films with p-type charge transport having a transconductance of 10 µS at a gate voltage of -0.9 V in an OECT device structure.

Laser-Fabricated 2D Molybdenum Disulfide Electronic Sensor Arrays for Rapid, Low-Cost, Ultrasensitive Detection of Influenza A and SARS-Cov-2.

Multiplex electronic antigen sensors for detection of SARS-Cov-2 spike glycoproteins and hemagglutinin from influenza A are fabricated using scalable processes for straightforward transition to economical mass-production. The sensors utilize the sensitivity and surface chemistry of a 2D MoS2 transducer for attachment of antibody fragments in a conformation favorable for antigen binding with no need for additional linker molecules. To make the devices, ultra-thin layers (3 nm) of amorphous MoS2 are sputtered over pre-patterned metal electrical contacts on a glass chip at room temperature. The amorphous MoS2 is then laser annealed to create an array of semiconducting 2H-MoS2 transducer regions between metal contacts. The semiconducting crystalline MoS2 region is functionalized with monoclonal antibody fragments complementary to either SARS-CoV-2 S1 spike protein or influenza A hemagglutinin. Quartz crystal microbalance experiments indicate strong binding and maintenance of antigen avidity for antibody fragments bound to MoS2. Electrical resistance measurements of sensors exposed to antigen concentrations ranging from 2-20 000 pg mL-1 reveal selective responses. Sensor architecture is adjusted to produce an array of sensors on a single chip suited for detection of analyte concentrations spanning six orders of magnitude from pg mL-1 to µg mL-1.

Light-matter coupling in large-area van der Waals superlattices.

Two-dimensional (2D) crystals have renewed opportunities in design and assembly of artificial lattices without the constraints of epitaxy. However, the lack of thickness control in exfoliated van der Waals (vdW) layers prevents realization of repeat units with high fidelity. Recent availability of uniform, wafer-scale samples permits engineering of both electronic and optical dispersions in stacks of disparate 2D layers with multiple repeating units. Here we present optical dispersion engineering in a superlattice structure comprising alternating layers of 2D excitonic chalcogenides and dielectric insulators. By carefully designing the unit cell parameters, we demonstrate greater than 90% narrow band absorption in less than 4 nm of active layer excitonic absorber medium at room temperature, concurrently with enhanced photoluminescence in square-centimetre samples. These superlattices show evidence of strong light-matter coupling and exciton-polariton formation with geometry-tuneable coupling constants. Our results demonstrate proof of concept structures with engineered optical properties and pave the way for a broad class of scalable, designer optical metamaterials from atomically thin layers.

Neutrophil depletion blocks early collagen degradation in repairing cholestatic rat livers.

Biliary obstruction results in a well-characterized cholestatic inflammatory and fibrogenic process; however, the mechanisms and potential for liver repair remain unclear. We previously demonstrated that Kupffer cell depletion reduces polymorphonuclear cell (neutrophil) (PMN) and matrix metalloproteinase (MMP)8 levels in repairing liver. We therefore hypothesized that PMN-dependent MMP activity is essential for successful repair. Male Sprague-Dawley rats received reversible biliary obstruction for 7 days, and the rat PMN-specific antibody RP3 was administered 2 days before biliary decompression (repair) and continued daily until necropsy, when liver underwent morphometric analysis, immunohistochemistry, quantitative RT-PCR, and in situ zymography. We found that RP3 treatment did not reduce Kupffer cell or monocyte number but significantly reduced PMN number at the time of decompression and 2 days after repair. RP3 treatment also blocked resorption of type I collagen. In addition, biliary obstruction resulted in increased expression of MMP3, MMP8, and tissue inhibitor of metalloproteinase 1. Two days after biliary decompression, both MMP3 and tissue inhibitor of metalloproteinase 1 expression declined toward sham levels, whereas MMP8 expression remained elevated and was identified in bile duct epithelial cells by immunohistochemistry. PMN depletion did not alter the hepatic expression of these genes. Conversely, collagen-based in situ zymography demonstrated markedly diminished collagenase activity following PMN depletion. We conclude that PMNs are essential for collagenase activity and collagen resorption during liver repair, and speculate that PMN-derived MMP8 or PMN-mediated activation of intrinsic hepatic MMPs are responsible for successful liver repair.

Direct Optoelectronic Imaging of 2D Semiconductor-3D Metal Buried Interfaces.

The semiconductor-metal junction is one of the most critical factors for high-performance electronic devices. In two-dimensional (2D) semiconductor devices, minimizing the voltage drop at this junction is particularly challenging and important. Despite numerous studies concerning contact resistance in 2D semiconductors, the exact nature of the buried interface under a three-dimensional (3D) metal remains unclear. Herein, we report the direct measurement of electrical and optical responses of 2D semiconductor-metal buried interfaces using a recently developed metal-assisted transfer technique to expose the buried interface, which is then directly investigated using scanning probe techniques. We characterize the spatially varying electronic and optical properties of this buried interface with <20 nm resolution. To be specific, potential, conductance, and photoluminescence at the buried metal/MoS2 interface are correlated as a function of a variety of metal deposition conditions as well as the type of metal contacts. We observe that direct evaporation of Au on MoS2 induces a large strain of ∼5% in the MoS2 which, coupled with charge transfer, leads to degenerate doping of the MoS2 underneath the contact. These factors lead to improvement of contact resistance to record values of 138 kΩ µm, as measured using local conductance probes. This approach was adopted to characterize MoS2-In/Au alloy interfaces, demonstrating contact resistance as low as 63 kΩ µm. Our results highlight that the MoS2/metal interface is sensitive to device fabrication methods and provide a universal strategy to characterize buried contact interfaces involving 2D semiconductors.

Influence of experience, case load, and stage distribution on outcome of endoscopic laser surgery for TTTS--a review.

OBJECTIVE: Survival (> or =1 twin) after laser surgery for patients with twin-to-twin transfusion syndrome (TTTS) ranges from 65 to 93%. However, most studies are noncontrolled and retrospective, and have included a limited number of patients. The aim of this study was to perform a systematic review of outcomes after laser surgery in patients with TTTS. METHODS: We conducted database and manual searches of reference lists and pertinent journals published between 1995 and 2009 that report outcomes of laser surgery in patients with TTTS. Two authors performed the search independently of each other. There exist only two randomized controlled trials, each with fewer than 80 patients having undergone laser surgery. Uncontrolled and retrospective series were therefore considered as well. Studies had to report sufficient information on inclusive dates, stage distribution, overall neonatal survival, and neonatal survival of at least one twin. Of the 486 studies identified, we considered 19 studies. RESULTS: For each series, 95% confidence intervals (CI) were calculated. Survival was plotted against the date of publication, number of patients/series, gestational age at delivery, and proportion of advanced cases. Univariate analysis was performed to detect significant differences. Our meta-analysis, which included 1484 patients, shows 81.2% survival of at least one twin (CI: 79.1-83.2%). The average survival of at least one twin for the entire population remained within the CI of all but one series. Neither case load, nor stage distribution, nor chronological date of the study affected the survival. CONCLUSION: A systematic review of endoscopic laser surgery performed in patients with TTTS failed to show a significant impact of high caseloads, disease severity distribution, or improvements in technique.

Transferrable AlGaN/GaN High-Electron Mobility Transistors to Arbitrary Substrates via a Two-Dimensional Boron Nitride Release Layer.

Mechanical transfer of high-performing thin-film devices onto arbitrary substrates represents an exciting opportunity to improve device performance, explore nontraditional manufacturing approaches, and paves the way for soft, conformal, and flexible electronics. Using a two-dimensional boron nitride release layer, we demonstrate the transfer of AlGaN/GaN high-electron mobility transistors (HEMTs) to arbitrary substrates through both direct van der Waals bonding and with a polymer adhesive interlayer. No device degradation was observed because of the transfer process, and a significant reduction in device temperature (327-132 °C at 600 mW) was observed when directly bonded to a silicon carbide (SiC) wafer relative to the starting wafer. With the use of a benzocyclobutene (BCB) adhesion interlayer, devices were easily transferred and characterized on Kapton and ceramic films, representing an exciting opportunity for integration onto arbitrary substrates. Upon reduction of this polymer adhesive layer thickness, the AlGaN/GaN HEMTs transferred onto a BCB/SiC substrate resulted in comparable peak temperatures during operation at powers as high as 600 mW to the as-grown wafer, revealing that by optimizing interlayer characteristics such as thickness and thermal conductivity, transferrable devices on polymer layers can still improve performance outputs.

The pediatric surgeons' contribution to in utero treatment of twin-to-twin transfusion syndrome.

OBJECTIVE: To evaluate the outcome of twin-to-twin transfusion syndrome (TTTS) treated using a combination of endoscopic fetal surgery-specific techniques and surgical restraint. SUMMARY BACKGROUND DATA: TTTS is a condition of identical twins that, if progressive and left untreated, leads to 100% mortality. The best treatment option is obliteration of the intertwin placental anastomoses, but fetal surgery carries significant maternal and fetal risks. Even if successful, percutaneous endoscopic laser ablation of placental vessels (LASER) causes premature rupture of membranes (PROM) in 10% to 20% of pregnancies. Patient selection is particularly critical because the progression of the disease is unpredictable. This has prompted many to intervene early, yielding survival rates of >=1 twin of 75% to 80%. METHODS: We developed a minimally invasive approach to fetal surgery, a unique membrane sealing technique and a conservative algorithm that reserves intervention for severe TTTS. Pregnancies with TTTS (stages I-IV) managed in the last 8 years were reviewed. LASER was offered in stage III/IV only. RESULTS: Ninety-eight cases of TTTS were managed in a pediatric surgery/maternal-fetal medicine collaborative Fetal Treatment Program-39 were observed (40%) and 59 underwent LASER (60%). Survival of >= twin was seen in 82.7%, and overall survival was 69.4%. These survival rates are similar to, or better than, other comparable series with similar stage distribution (low:high stage ratio 1:1) in which all patients underwent LASER. PROM rate was 4%. CONCLUSIONS: Reserving LASER treatment for severe TTTS results in outcomes similar to, or better than, LASER for all stages. Applying fetal surgery-specific endoscopic techniques, including port-site sealing, reduces postoperative complications.

Dexamethasone alters the hepatic inflammatory cellular profile without changes in matrix degradation during liver repair following biliary decompression.

BACKGROUND: Biliary atresia is characterized by extrahepatic bile duct obliteration along with persistent intrahepatic portal inflammation. Steroids are standard in the treatment of cholangitis following the Kasai portoenterostomy, and were advocated for continued suppression of the ongoing immunologic attack against intrahepatic ducts. Recent reports, however, have failed to demonstrate an improved patient outcome or difference in the need for liver transplant in postoperative patients treated with a variety of steroid regimes compared with historic controls. In the wake of progressive liver disease despite biliary decompression, steroids are hypothesized to suppress inflammation and promote bile flow without any supporting data regarding their effect on the emerging cellular and molecular mechanisms of liver repair. We have previously shown in a reversible model of cholestatic injury that repair is mediated by macrophages, neutrophils, and specific matrix metalloproteinase activity (MMP8); we questioned whether steroids would alter these intrinsic mechanisms. METHODS: Rats underwent biliary ductal suspension for 7 d, followed by decompression. Rats were treated with IV dexamethasone or saline at the time of decompression. Liver tissue obtained at the time of decompression or after 2 d of repair was processed for morphometric analysis, immunohistochemistry, and quantitative RT-PCR. RESULTS: There was a dramatic effect of dexamethasone on the inflammatory component with the initiation of repair. Immunohistochemistry revealed a reduction of both ED1+ hepatic macrophages and ED2+Kupffer cells in repair compared with saline controls. Dexamethasone treatment also reduced infiltrating neutrophils by day 2. TNF-alpha expression, increased during injury in both saline and dexamethasone groups, was markedly reduced by dexamethasone during repair (day 2) whereas IL-6, IL-10, and CINC-1 remained unchanged compared with saline controls. Dexamethasone reduced both MMP8 and TIMP1 expression by day 2, whereas MMP9, 13, and 14 were unchanged compared with sham controls. Despite substantial cellular and molecular changes during repair, collagen resorption was the same in both groups CONCLUSION: Dexamethasone has clear effects on both the hepatic macrophage populations and infiltrating neutrophils following biliary decompression. Altered MMP and TIMP gene expression might suggest that steroids have the potential to modify matrix metabolism during repair. Nevertheless, successful resorption of collagen fibrosis proceeded presumably through other MMP activating mechanisms. We conclude that steroids do not impede the rapid intrinsic repair mechanisms of matrix degradation required for successful repair.

Endotoxin alters early fetal lung morphogenesis.

BACKGROUND: The effects of immaturity and hypoplasia of the premature lung can be affected by proinflammatory stimuli in late gestation or the postnatal period from acute lung injury secondary to intensive ventilatory management or the metabolic consequences of surgery. These stimuli alter alveolarization and contribute to bronchopulmonary dysplasia. While prior research has focused primarily on late gestational effects of inflammation on alveolar development, we sought to study whether early gestational exposure to endotoxin affects branching morphogenesis, during the critical pseudoglandular stage of lung development. METHOD: Gestational day 15 (E15) fetal rat lung explants (term = 22 d) were treated with either 200 ng/mL or 2 microg/mL lipopolysaccharides (LPS) with controls and examined daily by phase microscopy. After 5 d, explants were fixed in 4% formaldehyde, paraffin embedded, and sectioned at 5 mum in the coronal plane. Immunohistochemical analysis was performed with platelet endothelial cell adhesion molecule (PECAM) to define endothelial cells, vascular endothelial growth factor (VEGF) to examine endothelial mitogenesis, and COX-2 antibodies as a marker for prostaglandin synthesis. Real-time PCR examined inducible nitric oxide synthase (iNOS), FGF9, FGF10, and FGFr2 gene expression. Air space fraction and airway epithelium were analyzed with Image J software. RESULTS: Phase contrast microscopy and hematoxylin-eosin histology revealed progressive, dose-related changes in air sac contraction and interstitial thickening. Compared with control E15 explants, day 5 explants incubated with high dose LPS demonstrated thickened and shrunken airway sacs with stunted branching and increased matrix deposition in interstitial areas. By immunohistochemical staining, COX-2 was quantitatively increased after high dose LPS exposure, while PECAM was reduced. VEGF expression was unaltered. LPS increased iNOS, but decreased FGF9, FGF10, and FGFr2 gene expression. CONCLUSIONS: These data support evidence for an inflammatory effect of LPS on the early phase of lung development in the fetal rat, affecting branching morphogenesis during the pseudoglandular phase. Fetal endothelial cells are clearly affected, while COX-2 elevation suggests activation of an as yet undefined fetal pulmonary inflammatory cascade. We speculate that proinflammatory stimuli may ultimately lead to abnormal pulmonary development via fibroblastic growth factor (FGF)-directed mechanisms that affect epithelial-mesenchymal interaction and differentiation at a much earlier gestational age than was previously recognized.

Surgical performance with head-mounted displays in laparoscopic surgery.

INTRODUCTION: The difficulties of laparoscopic surgery include two-dimensional image projection and loss of alignment between the surgeon's hands and visual field. Head-mounted displays (HMDs) allow freedom from gazing at a stationary overhead monitor, thus improving ergonomics. Modern HMDs offer greatly improved image quality and reduced bulk and weight. We compared two types of HMDs with conventional overhead image display. MATERIALS AND METHODS: Twelve preclinical medical students (i.e., laparoscopic novices) completed the standardized bead-passing task in a Fundamentals of Laparoscopic Surgery box trainer, using a wall-mounted monitor(WALL), a solid-state high-resolution dual full-visual graphic array (VGA) HMD (HIGH-HMD), or a lightweight commercial 1/4 VGA HMD (LOW-HMD). Participants performed each task by using the three image displays. The order in which they performed each test was randomly assigned to minimize the carryover effect.Students were then asked to grade comfort and image quality on a scale from 1 (worst) to 5 (best). Statistical comparison of the time per bead was performed with the Kruskal-Wallis test, and P < 0.05 was considered significant. RESULTS: Average time per bead (total beads = 12/participant/test) was 14.2 seconds for WALL, 13.2 seconds for LOW-HMD, and 12.5 seconds for HIGH-HMD (P 0.05). The comfort ratings were 3.67 +/- 0.82, 3.50 +/- 1.38,and 3.83 +/- 0.75, respectively, and image quality was rated as 3.00 +/- 0.63, 2.83 +/- 1.47 and 4.67 +/- 0.52, respectively. CONCLUSIONS: The high-resolution HMD offered significantly better image quality and allowed faster task performance than a lower resolution model of HMD, and both performed better than the overhead display. The high-resolution HMD was not significantly more comfortable than the low-resolution model, given its added weight. HMDs alone may only be of incremental benefit in improving performance in laparoscopic surgery.However, their greatest promise is in their combination with other advances in imaging and image manipulation technology, as they open the door to individualized image display.

Dual localization technique for thoracoscopic resection of lung lesions in children.

BACKGROUND: Thoracoscopic wedge resection has gained widespread acceptance as a method of resecting pulmonary metastases in pediatric cancer patients. This is most successful for lesions on the pleural surface that can be identified without palpation. Deeper lesions can be marked by preoperative computed tomography (CT)-guided techniques, but neither needle localization nor dye injection alone is foolproof. In this paper, we present our experience with a dual localization technique. METHODS: Under CT guidance, a 20-G needle is advanced to within 1 cm of the lesion and 0.1 mL of methylene blue: Low osmolar contrast (4:1 ratio) is injected. A Kopans breast biopsy hook wire is then introduced through the needle and its tip placed within the lesion. Its tail is cut flush with the chest wall. The patient is transferred to the operating room, and a wedge resection around the hook wire is performed thoracoscopically. RESULTS: Six deep pulmonary metastatic lesions were preoperatively localized in 4 pediatric patients (ages, 6-17).Median localization time was 30 minutes. All lesions were successfully marked and identified at operation.Margin-free resection of the lesion was successful in all cases. CONCLUSIONS: Thoracoscopic resection of metastatic pulmonary lesions in children, using preoperative localization with both wire localization and methylene blue/contrast injection, is safe and effective. This method allows the successful localization of lesions, even in the event of either dislodgement of the wire or over infusion of the methylene blue dye.

Two-Dimensional Materials in Biosensing and Healthcare: From In Vitro Diagnostics to Optogenetics and Beyond.

Since the isolation of graphene in 2004, there has been an exponentially growing number of reports on layered two-dimensional (2D) materials for applications ranging from protective coatings to biochemical sensing. Due to the exceptional, and often tunable, electrical, optical, electrochemical, and physical properties of these materials, they can serve as the active sensing element or a supporting substrate for diverse healthcare applications. In this review, we provide a survey of the recent reports on the applications of 2D materials in biosensing and other emerging healthcare areas, ranging from wearable technologies to optogenetics to neural interfacing. Specifically, this review provides (i) a holistic evaluation of relevant material properties across a wide range of 2D systems, (ii) a comparison of 2D material-based biosensors to the state-of-the-art, (iii) relevant material synthesis approaches specifically reported for healthcare applications, and (iv) the technological considerations to facilitate mass production and commercialization.