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Stabilization Of The CN 3 5− Anion In Recoverable High‐pressure Ln 3 O 2 (CN 3 ) (Ln=La, Eu, Gd, Tb, Ho, Yb) Oxoguanidinates
Abstract A series of isostructural Ln 3 O 2 (CN 3 ) (Ln=La, Eu, Gd, Tb, Ho, Yb) oxoguanidinates was synthesized under high‐pressure (25–54 GPa) high‐temperature (2000–3000 K) conditions in laser‐heated diamond anvil cells. The crystal structure of this novel class of compounds was determined via synchrotron single‐crystal X‐ray diffraction (SCXRD) as well as corroborated by X‐ray absorption near edge structure (XANES) measurements and density functional theory (DFT) calculations. The Ln 3 O 2 (CN 3 ) solids are composed of the hitherto unknown CN 3 5− guanidinate anion—deprotonated guanidine. Changes in unit cell volumes and compressibility of Ln 3 O 2 (CN 3 ) (Ln=La, Eu, Gd, Tb, Ho, Yb) compounds are found to be dictated by the lanthanide contraction phenomenon. Decompression experiments show that Ln 3 O 2 (CN 3 ) compounds are recoverable to ambient conditions. The stabilization of the CN 3 5− guanidinate anion at ambient conditions provides new opportunities in inorganic and organic synthetic chemistry.
The Structural Transition Behavior of CdSe/ZnS Core/shell Quantum Dots under High Pressure
The structural phase transition of CdSe/ZnS core/shell quantum dots (QDs) has been studied by in situ angle-dispersive X-ray diffraction under high pressure up to 53.6?GPa. The CdSe core transforms from wurtzite to rock-salt structure near 6.3?GPa and then to Cmcm or distorted Cmcm structure probably occurs at 45.1?GPa which has not been observed in CdSe nanomaterials before. The critical pressure from wurtzite to rock-salt and the bulk modulus of rock-salt phase are much higher than those for bulky and uncapped nanoparticle CdSe. The released sample can be kept in rock-salt phase for a certain time, verified by photoluminescence (PL) spectra, quite different from the reversible transition for pure CdSe. A reasonable interpretation of the experimental phenomena is given by comparing the bulk modulus of the core and shell and studying the stress sate of the core after decompression. Our study suggests that capping a hard shell is an effective approach to quench the high pressure phase of nanomaterial with a reversible phase transition.
Piezochromic Behavior of 2,4,6-Triphenylpyrylium Tetrachloroferrate
In advanced photonics, there is a growing interest in piezochromic luminescent materials that exhibit multicolor switching, driven by their potential applications in optical recording, memory, and sensors. Here, the piezochromic behavior of 2,4,6-triphenylpyrylium tetrachloroferrate (Py-FeCl 4 ) under high pressures from 0 to 9 GPa is reported. The observed multicolor changing properties of Py-FeCl 4 (yellow–orange–red–maroon–black) are found to be fully reversible upon decompression to ambient conditions. The mechanism of Py-FeCl 4 piezochromism is investigated via Raman, infrared, and UV–vis spectroscopy combined with powder X-ray Diffraction. The absence of structural phase transitions as well as the abrupt shifts of bandgap values together with characteristic Raman and IR peaks within 0-9 GPa suggests that the Py-FeCl 4 multicoloring switching behavior is driven by an electron transfer between the inorganic FeCl 4 – anion and the organic pyrylium cation. The obtained results demonstrate that Py-FeCl 4 dye is a good candidate for developing high-pressure sensing technologies designed to function in extreme environments. Moreover, due to the inherent role of molecular-structure relationships in the pyrylium salt's photophysical properties, findings suggest the potential discovery of piezochromic behavior in other pyrylium compounds.
Data Federation Challenges in Remote Near-Real-Time Fusion Experiment Data Processing
Fusion energy experiments and simulations provide critical information needed to plan future fusion reactors. As next-generation devices like ITER move toward long-pulse experiments, analyses, including AI and ML, should be performed in a wide range of time and computing constraints, from near-real-time constraints, between-shot analysis, and to campaign-wide long-term analysis. However, the data volume, velocity, and variety make it extremely challenging for analyses using only local computational resources. Researchers need the ability to compose and execute workflows spanning edge resources to large-scale high-performance computing facilities.We present Delta, a system to address data analysis challenges, including AI/ML, in fusion science, by leveraging the ADIOS I/O library and middleware, to support executing science workflows over the wide area network for near-real-time streaming. We discuss the data federation challenges in performing remote workflows, focusing on on-going research work in (1) managing, reducing, and streaming data to minimize I/O and data movement overheads, (2) decompressing and reorganizing data for analysis, and (3) executing workflows for automated data analysis. We introduce examples for deep-learning based data analysis for the fusion domain and demonstrate how we use Delta to construct end-to-end workflows for a fusion device in Korea, connecting a remote DOE facility in the USA. The capability demonstrated by this project is the basis for improving the state of the art for near-real-time data federation amongst remote facilities.
Effect of Rotary Evaporator Water Bath Temperature on Recovery Rate of Phthalate Esters
To clarify the influence of water bath temperature on the decompression and concentration efficiency of a rotary evaporator, accurate control of the water bath temperature is required. Therefore, the water bath temperature control system of a rotary evaporator was studied using the recovery rate of phthalate esters (PAEs) as the indicator. The results showed that when the temperature of the rotary evaporator was set at 40°C, the actual temperature range of the concentrated liquid would change from 26–41 to 39–41°C. By modifying the water bath temperature control system, the recovery rate of PAEs could be increased from 72.4% to 85.6% to 93.2%–98.5%. This test indicates that temperature has a great influence on vacuum concentration, and the recovery rate of PAEs can be improved by modifying the water bath temperature control system used in the rotary evaporator.
Isothermal compression behavior of (Mg,Fe)O using neon as a pressure medium
We present isothermal volume compression behavior of two polycrystalline (Mg,Fe)O samples with FeO = 39 and 78 mol% up to {approx}90 GPa at 300 K using synchrotron X-ray diffraction and neon as a pressure-transmitting medium. For the iron-rich (Mg{sub 0.22}Fe{sub 0.78})O sample, a structural transition from the B1 structure to a rhombohedral structure was observed at 41.6 GPa, with no further indication of changes in structural or compression behavior changes up to 93 GPa. In contrast, a change in the compression behavior of (Mg{sub 0.61}Fe{sub 0.39})O was observed during compression at P {ge} 71 GPa and is indicative of a spin crossover occurring in the Fe{sup 2+} component of (Mg{sub 0.61}Fe{sub 0.39})O. The low-spin state exhibited a volume collapse of {approx}3.5%, which is a larger value than what was observed for a similar composition in a laser-heated NaCl medium. Upon decompression, the volume of the high-spin state was recovered at approximately 65 GPa. We therefore bracket the spin crossover at 65 {le} P (GPa) {le} 77 at 300 K (Mg{sub 0.61}Fe{sub 0.39})O. We observed no deviation from the B1 structure in (Mg{sub 0.61}Fe{sub 0.39})O throughout the pressure range investigated.
An infrared and Raman spectroscopic study of PbSO4-anglesite at high pressures
Infrared and Raman spectra of the ABX 4 compound anglesite (PbSO 4 ) were collected to 43 GPa at 300 K in three separate pressure media. A major transition in the spectra initiates at 23 GPa that is characterized by shifting and/or splitting of most of the fundamental vibrations of the sulfate group. On decompression, PbSO 4 reverts to the ambient anglesite (barite) structure. This transition is kinetically impeded within more hydrostatic pressure media and does not proceed to completion within a neon medium even at pressures as high as 43 GPa. The previously observed spectral shift at 13 GPa occurs in less hydrostatic media (such as 4:1 methanol:ethanol), and involves subtle splitting of a few modes, particularly the (SO 4 ) 2- tetrahedral stretching and bending-derived Raman and infrared modes. Another possible shift occurs near 33 GPa, and primarily involves the appearance of new sulfate antisymmetric bending modes in the infrared spectrum and the onset of new sulfate antisymmetric stretching modes in the Raman spectrum. It is likely that PbSO 4 begins to convert sluggishly to the $P2_12_12_1$ ABX4 structure starting at 23 GPa, with a possible additional crystallographic distortion or shift in compression mechanism occurring near 33 GPa. The spectral shift at 13 GPa in non-hydrostatic media may be a differential stress-induced structural distortion, or a subtle transition that is not accessible within more hydrostatic media. Our results emphasize that apparently equilibrium transitions such as that at 23 GPa may be notably suppressed within more hydrostatic media.
A Novel Fenestration Technique for Abdominal Aortic Dissection Membranes Using a Combination of a Needle Re-entry Catheter and the 'Cheese-wire' Technique
Purpose: This study was designed to demonstrate the applicability of a combined needle-based re-entry catheter and 'cheese-wire' technique for fenestration of abdominal aortic dissection membranes. Methods: Four male patients (mean age: 65 years) with acute complicated aortic type B dissections were treated at our institution by fenestrating the abdominal aortic dissection membrane using a hybrid technique. This technique combined an initial membrane puncture with a needle-based re-entry catheter using a transfemoral approach. A guidewire was passed through the re-entry catheter and across the membrane. Using a contralateral transfemoral access, this guidewire was then snared, creating a through-and-through wire access. The membrane was then fenestrated using the cheese-wire maneuver. Results: We successfully performed: (a) membrane puncture; (b) guidewire passage; (c) guidewire snaring; and (d) cheese-wire maneuver in all four cases. After this maneuver, decompression of the false lumen and acceptable arterial inflow into the true lumen was observed in all cases. The dependent visceral arteries were reperfused. In one case, portions of the fenestrated membrane occluded the common iliac artery, which was immediately and successfully stented. In another case, long-standing intestinal hypoperfusion before the fenestration resulted in reperfusion-related shock and intraoperative death of the patient. Conclusions: The described hybrid approach for fenestration of dissection membranes is technically feasible and may be established as a therapeutic method in cases with a complicated type B dissection.
Quantitative Discomanometry: Correlation of Intradiscal Pressure Values to Pain Reduction in Patients With Intervertebral Disc Herniation Treated With Percutaneous, Minimally Invasive, Image-Guided Techniques
Purpose: To illustrate quantitative discomanometry's (QD) diagnostic efficacy and predictive value in discogenic-pain evaluation in a prospective study correlating intradiscal pressure values with pain reduction after percutaneous image-guided technique (i.e., percutaneous decompression, PD). Materials and Methods: During the last 3 years, 36 patients [21 male and 15 female (mean age 36 {+-} 5.8 years)] with intervertebral disc hernia underwent QD before PD. Under absolute sterilization and fluoroscopy, a mixture of contrast medium and normal saline (3:1 ratio) was injected. A discmonitor performed a constant rate injection and recorded pressure and volume values, thus producing the relative pressure-volume curve. PD was then performed. Pain reduction and improved mobility were recorded at 3, 12, and 24 months after PD using clinical evaluation and a numeric visual scale (NVS; 0 to 10 units). Results: Mean pain values of 7.5 {+-} 1.9 (range 4 to 8) NVS units were recorded before PD; these decreased to 2.9 {+-} 2.44 at 3 months, 1.0 {+-} 1.9 at 12 months, and 1.0 {+-} 1.9 NVS units at 24 months after PD. Recorded correlations (pressure, volume, significant pain-reduction values) with bilateral statistical significance included a maximum injected volume of 2.4 ml (p = 0.045), P{sub o} < 14 psi [initial pressure required to inject 0.1 ml of the mixture inside the disc (p = 0.05)], P{sub max} {<=} 65 psi [greatest pressure value on the curve (p = 0.018)], and P{sub max} - P{sub o} {<=} 47 psi (p = 0.038). Patients meeting these pressure or volume cut-off points, either independently or as a total, had significant pain reduction (>4 NVS units) after PD. No complications were noted. Conclusions: QD is an efficient technique that may have predictive value for discogenic pain evaluation. It might serve as a useful tool for patient selection for intervertebral disc therapies.
Percutaneous Intraductal Radiofrequency Ablation is a Safe Treatment for Malignant Biliary Obstruction: Feasibility and Early Results
Purpose. Previous clinical studies have shown the safety and efficacy of this novel radiofrequency ablation catheter when used for endoscopic palliative procedures. We report a retrospective study with the results of first in man percutaneous intraductal radiofrequency ablation in patients with malignant biliary obstruction. Methods. Thirty-nine patients with inoperable malignant biliary obstruction were included. These patients underwent intraductal biliary radiofrequency ablation of their malignant biliary strictures following external biliary decompression with an internal-external biliary drainage. Following ablation, they had a metal stent inserted. Results. Following this intervention, there were no 30-day mortality, hemorrhage, bile duct perforation, bile leak, or pancreatitis. Of the 39 patients, 28 are alive and 10 patients are dead with a median survival of 89.5 (range 14-260) days and median stent patency of 84.5 (range 14-260) days. One patient was lost to follow-up. All but one patient had their stent patent at the time of last follow-up or death. One patient with stent blockage at 42 days postprocedure underwent percutaneous transhepatic drain insertion and restenting. Among the patients who are alive (n = 28) the median stent patency was 92 (range 14-260) days, whereas the patients who died (n = 10) had a median stent patency of 62.5 (range 38-210) days. Conclusions. In this group of patients, it appears that this new approach is feasible and safe. Efficacy remains to be proven in future, randomized, prospective studies.
Percutaneous Intraductal Radiofrequency Ablation for Clearance of Occluded Metal Stent in Malignant Biliary Obstruction: Feasibility and Early Results
Purpose: The major complication occurring with biliary stents is stent occlusion, frequently seen because of tumour in-growth, epithelial hyperplasia, and sludge deposits, resulting in recurrent jaundice and cholangitis. We report a prospective study with the results of first in man percutaneous intraductal radiofrequency (RF) ablation to clear the blocked metal stents in patients with malignant biliary obstruction using a novel bipolar RF catheter. Methods: Nine patients with malignant biliary obstruction and blocked metal stents were included. These patients underwent intraductal biliary RF ablation through the blocked metal stent following external biliary decompression with an internal–external biliary drainage. Results: All nine patients had their stent patency restored successfully without the use of secondary stents. Following this intervention, there was no 30-day mortality, haemorrhage, bile duct perforation, bile leak, or pancreatitis. Of the nine patients, six are alive and three patients are dead with a median follow-up of 122 (range 50–488) days and a median stent patency of 102.5 (range 50–321) days. Six patients had their stent patent at the time of last follow-up or death. Three patients with stent blockage at 321, 290, and 65 days postprocedure underwent percutaneous transhepatic drain insertion and repeat ablation. Conclusions: In this selective group of patients, it appears that this new approach is safe and feasible. Efficacy remains to be proven in future, randomized, prospective studies.
Transcatheter Embolotherapy with N-Butyl Cyanoacrylate for Ectopic Varices
PurposeTo address technical feasibility and clinical outcome of transcatheter embolotherapy with N-butyl cyanoacrylate (NBCA) for bleeding ectopic varices.MethodsThe institutional review board approved this retrospective study and waived informed consent. From January 2004 to June 2013, a total of 12 consecutive patients received transcatheter embolotherapy using NBCA for bleeding ectopic varices in our institute. Clinical and radiologic features of the endovascular procedures were comprehensively reviewed.ResultsPreprocedural computed tomography images revealed ectopic varices in the jejunum (n = 7), stoma (n = 2), rectum (n = 2), and duodenum (n = 1). The 12 procedures consisted of solitary embolotherapy (n = 8) and embolotherapy with portal decompression (main portal vein stenting in 3, transjugular intrahepatic portosystemic shunt in 1). With regard to vascular access, percutaneous transhepatic access (n = 7), transsplenic access (n = 4), and transjugular intrahepatic portosystemic shunt tract (n = 1) were used. There was no failure in either the embolotherapy or the vascular accesses (technical success rate, 100 %). Two patients died within 1 month from the procedure from preexisting fatal medical conditions. Only one patient, with a large varix that had been partially embolized by using coils and NBCA, underwent rebleeding 5.5 months after the procedure. The patient was retreated with NBCA and did not undergo any bleeding afterward for a follow-up period of 2.5 months. The remaining nine patients did not experience rebleeding during the follow-up periods (range 1.5–33.2 months).ConclusionTranscatheter embolotherapy using NBCA can be a useful option for bleeding ectopic varices.
Risk Factors for Immediate and Delayed-Onset Fever After Percutaneous Transhepatic Biliary Drainage
ObjectivesTo prospectively investigate the pre and intra-procedural risk factors for immediate (IF) and delayed-onset (DOF) fever development after percutaneous transhepatic biliary drainage (PTBD).MethodsInstitutional review board approval and informed patient consent were obtained. Between February 2013 and February 2014, 97 afebrile patients (77 at the Sapienza University of Rome, Italy and 20 at the Sun Yat-sen University of Guangzhou, China) with benign (n = 31) and malignant (n = 66) indications for a first PTBD were prospectively enrolled. Thirty pre- and intra-procedural clinical/radiological characteristics, including the amount of contrast media injected prior to PTBD placement, were collected in relation to the development of IF (within 24 h) or DOF (after 24 h). Fever was defined as ≥37.5 °C. Binary logistic regression analysis was used to assess independent associations with IF and DOF.ResultsFourteen (14.4 %) patients developed IF and 17 (17.5 %) developed DOF. At multivariable analysis, IF was associated with pre-procedural absence of intrahepatic bile duct dilatation (OR 63.359; 95 % CI 2.658–1510.055; P = 0.010) and low INR (OR 4.7 × 10{sup −4}; 95 % CI 0.000–0.376; P = 0.025), while DOF was associated with unsatisfactory biliary drainage at the end of PTBD (OR 4.571; 95 % CI 1.161–17.992; P = 0.030).ConclusionsThe amount of contrast injected is not associated with post-PTBD fever development. Unsatisfactory biliary drainage at the end of PTBD is associated with DOF, suggesting that complete biliary tree decompression should be pursued within the first PTBD. Patients with unsatisfactory drainage and those with the absence of pre-procedural intrahepatic bile duct dilatation, which is associated with IF, require tailored post-PTBD management.
Median Arcuate Ligament Syndrome: A Single-Center Experience with 23 Patients
BackgroundMedian arcuate ligament syndrome (MALS) is a rare entity that occurs when the median arcuate ligament of the diaphragm is low-lying, causing a compression to the underlying celiac trunk. We reviewed the vascular changes associated with MALS in an effort to emphasize the seriousness of this disease and the complications that may result.MethodsThis is a retrospective descriptive analysis of 23 consecutive patients diagnosed with MALS between January 1, 2012 and December 31, 2015 at a tertiary medical center. Computed tomographic (CT) scans, medical records, and patient follow-up were reviewed.ResultsThe number of patients included herein was 23. The median age was 56 years (17–83). Sixteen patients (69.6%) had a significant arterial collateral circulation. Eleven patients (47.8%) were found to have visceral artery aneurysms; 4 patients (36.4%) bled secondary to aneurysm rupture. All ruptured aneurysms were treated with endovascular approach. The severity of the hemodynamic changes appears to be greater with complete occlusion,ConclusionsMALS causes pathological hemodynamic changes within the abdominal vasculature. Follow-up is advised for patients who develop a collateral circulation. Resulting aneurysms should preferably be treated when the size ratio approaches three. Treatment of these aneurysms can be done via an endovascular approach coupled with possible celiac artery decompression to restore physiologic blood flow.
Interventional Management of Subcapsular Hepatic Hematoma with Hepatic Compartment Syndrome After Laparoscopic Adrenalectomy
Hepatic compartment syndrome is an increase in intrahepatic pressure sufficient to cause compromised hepatic perfusion. Early recognition and prompt management are essential for preventing catastrophic consequences including ischemic liver failure and hypovolemic shock. This is the rare case of laparoscopic adrenalectomy resulting in subcapsular hepatic hematoma with hepatic compartment syndrome. Contrast-enhanced computed tomography demonstrated extensive subcapsular hepatic hematoma with collapse of portal vein and inferior vena cava suggesting impending compartment syndrome. Diagnostical catheter angiography of the liver revealed innumerable foci of petechial extravasation from disrupted isolated arteries. Emergent percutaneous catheter decompression and transarterial embolization were successful.
Serious Neurological Complication Resulting from Inadvertent Intradiscal Injection During Fluoroscopically Guided Interlaminar Epidural Steroid Injection
We describe the case of a 30-year-old patient who was referred for lumbar epidural corticosteroid injection due to right L5 radiculopathy. Two months earlier, MRI demonstrated a right large paracentral L4–L5 disk extrusion causing disabling L5 radiculopathy. The L4–L5 level was selected for interlaminar injection, using fluoroscopic guidance. During injection, the patient developed severe pain in both lower extremities. Thus, the procedure was immediately terminated. Paraplegia occurred within several minutes. Urgent lumbar spine CT and MRI demonstrated contrast material in a massive extruded disk fragment and substantial increase in size of the disk extrusion compared to pre-injection MRI. Emergency surgery was performed for lumbar decompression and discectomy. Although rare, serious neurological complication can result from inadvertent intradiscal injection of contrast material during lumbar epidural injection. This case illustrates the importance of recognizing the possibility of dynamic change in the size of an extruded disk fragment when the MRI precedes injection by a substantial time interval. Level of Evidence: IV, Case Series.
Clinical Efficacy of Transjugular Intrahepatic Portosystemic Shunt Created with Expanded Polytetrafluoroethylene-Covered Stent-Grafts: 8-mm Versus 10-mm
Purpose: Conflicting data exist regarding the appropriate shunt diameter for transjugular intrahepatic portosystemic shunt (TIPS) creation in cirrhotic patients. This study was designed to compare the clinical efficacy of TIPS using stent-grafts with 8- and 10-mm diameters. Methods: In this retrospective study, cirrhotic patients who underwent TIPS technical successfully for the prevention of variceal rebleeding from December 2011 to June 2015 were included. Thirty-four patients with 8-mm TIPS and 380 patients with 10-mm TIPS were identified. Propensity score matching method produced 32 patients in each group for comparison. Results: Baseline characteristics between two groups were comparable. There was no significant difference in variceal rebleeding rate between the two groups. The cumulative incidence of variceal rebleeding after 1 and 3 years was 6.4% and 35.5% in the 8-mm group, respectively, and 14.2% and 24.9% in the 10-mm group, respectively (P = 0.663). 8-mm TIPS conferred a significant decrease in hepatic encephalopathy (HE) rate compared with the 10-mm TIPS (16.1 vs. 32.6% at 1 year, 27.8 vs. 53.2% at 3 years, P = 0.034). The cumulative survival rates were similar between the two groups: 93.3% and 79.6% at 1 and 3 years, respectively, in the 8-mm TIPS group vs. 87.3% and 72.1% at 1 and 3 years, respectively, in the 10-mm TIPS group (P = 0.451). Conclusion: The placement of 8-mm TIPS was sufficient to decompress the portal hypertension and prevent variceal rebleeding. The use of the 8-mm stent-graft can decrease HE rates compared with 10-mm stent-graft, although no survival benefit was observed.