Lower Double-Wall Puncture Rate During Ultrasound-Guided Internal Jugular Vein Cannulation Using Sharper, Narrower-Gauge, and/or Length-Optimized Needles: A 6-Year Quality Improvement Clinical Series in Adult Patients.

Background: During internal jugular vein (IJV) cannulation, needle tip injury to vulnerable subjacent cervical anatomic structures can be prevented if the cannulating needle tip is not permitted, even momentarily, to penetrate the deep portion of the IJV wall, an event known as double-wall puncture (DWP), also called posterior wall puncture. Methods: We conducted a 6-year ultrasound-guided IJV cannulation quality improvement project, seeking to minimize the occurrence of DWP in 228 adult patients using needles of different gauge and tip sharpness. Most needles were length-optimized to the distance between the skin puncture site and the IJV mid-lumen for a selected angle of needle insertion by (1) using a nylon screw-on needle stop or (2) using a cannulating needle that already had the desired shaft length. Results: Standard central venous cannulation kit needles were long enough to reach or traverse the deepest portion of the IJV wall in nearly all patients. Use of extra-sharp, smaller-diameter needles in place of standard needles was associated with a 26.3% relative reduction in DWP rate. Use of needles length-optimized to reach only the IJV mid-lumen was associated with a 78.4% relative reduction in DWP rate. A 0% DWP rate was attained using length-optimized 21-gauge extra-sharp needles and length-optimized 20-gauge needles of intermediate sharpness. Conclusion: The 9.2% DWP rate achieved during this project was approximately half the rate reported at the time of project inception. Use of length-optimized, sharper, narrower-gauge cannulating needles may help avoid DWP during ultrasound-guided IJV cannulation.

A study of the growth mechanism of large-diameter double-wall TiO2 nanotube arrays fabricated by high voltage anodization.

Background: Research on the growth mechanism of titanium dioxide (TiO2) nanotube arrays fabricated by anodic oxidation is essential to achieve artificial control of the microstructure and to expand their applications. In our previous work, we reported the preparation of highly ordered large-diameter double-wall TiO2 nanotube arrays prepared by high voltage anodization. Methods: In this paper, we observed and analyzed the initial growth process of large-diameter double-wall TiO2 nanotube arrays anodized at 120 V in ethylene glycol electrolyte containing aluminum fluoride (NH4F) and water (H2O), such as the evolution of surface and cross-sectional morphologies, the influence of current density on growth rate, the transition process from nanoholes to nanotubes, and the evolution of dimples on the remaining substrate. Results: On the basis of our observations and inspirations from the existing viewpoints, we established growth models of large-diameter double-wall TiO2 nanotube arrays corresponding to different growth stages to explain the growth process. The growth rate of anodic oxide film changes accordingly with the current density. The compact anodic oxide film formed initially actually contains outer layer and inner layer, with no obvious interface between them. Then, the bottom even levels of the inner layer and outer layer bulge towards the substrate and become individual hemisphere-like structures. The inner layer becomes the outer wall, and the outer layer becomes inner wall. Eventually, V-shaped large-diameter and double-wall TiO2 nanotube arrays form. Conclusions: The results presented in this work are significant and provide a better understanding of the growth mechanism of large-diameter double-wall TiO2 nanotube arrays anodized by high voltage.

Efficient Inner-to-Outer Wall Energy Transfer in Highly Pure Double-Wall Carbon Nanotubes Revealed by Detailed Spectroscopy.

The coaxial stacking of two single-wall carbon nanotubes (SWCNTs) into a double-wall carbon nanotube (DWCNT), forming a so-called one-dimensional van der Waals structure, leads to synergetic effects that dramatically affect the optical and electronic properties of both layers. In this work, we explore these effects in purified DWCNT samples by combining absorption, wavelength-dependent infrared fluorescence-excitation (PLE), and wavelength-dependent resonant Raman scattering (RRS) spectroscopy. Purified DWCNTs are obtained by careful solubilization that strictly avoids ultrasonication or by electronic-type sorting, both followed by a density gradient ultracentrifugation to remove unwanted SWCNTs that could obscure the DWCNT characterization. Chirality-dependent shifts of the radial breathing mode vibrational frequencies and transition energies of the inner and outer DWCNT walls with respect to their SWCNT analogues are determined by advanced two-dimensional fitting of RRS and PLE data of DWCNT and their reference SWCNT samples. This exhaustive data set verifies that fluorescence from the inner DWCNT walls of well-purified samples is severely quenched through efficient energy transfer from the inner to the outer DWCNT walls. Combined analysis of the PLE and RRS results further reveals that this transfer is dependent on the inner and outer wall chirality, and we identify the specific combinations dominant in our DWCNT samples. These obtained results demonstrate the necessity and value of a combined structural characterization approach including PLE and RRS spectroscopy for bulk DWCNT samples.

Recent Advances in the Interfacial Shear and Dilational Rheology of Polymer Systems: From Fundamentals to Applications.

The study of the viscoelastic properties of polymer systems containing huge internal two-dimensional interfacial areas, such as blends, foams and multilayer films, is of growing interest and plays a significant role in a variety of industrial fields. Hence, interfacial rheology can represent a powerful tool to directly investigate these complex polymer-polymer interfaces. First, the current review summarizes the theoretical basics and fundamentals of interfacial shear rheology. Particular attention has been devoted to the double-wall ring (DWR), bicone, Du Noüy ring and oscillating needle (ISR) systems. The measurement of surface and interfacial rheological properties requires a consideration of the relative contributions of the surface stress arising from the bulk sub-phases. Here, the experimental procedures and methodologies used to correct the numerical data are described considering the viscoelastic nature of the interface. Second, the interfacial dilational rheology is discussed, starting with the theory and underlying principles. In particular, the Langmuir trough method, the oscillating spinning drop technique and the oscillating pendant drop technique are investigated. The major pioneering studies and latest innovations dedicated to interfacial rheology in both shear and dilatation-compression are highlighted. Finally, the major challenges and limits related to the development of high-temperature interfacial rheology at the molten state are presented. The latter shows great potential for assessing the interfaces of polymer systems encountered in many high-value applications.

Parallel Field-Effect Nanosensors Detect Trace Biomarkers Rapidly at Physiological High-Ionic-Strength Conditions.

Sensitivity and speed of detection are contradicting demands that profoundly impact the electrical sensing of molecular biomarkers. Although single-molecule sensitivity can now be achieved with single-nanotube field-effect transistors, these tiny sensors, with a diameter less than 1 nm, may take hours to days to capture the molecular target at trace concentrations. Here, we show that this sensitivity-speed challenge can be addressed using covalently functionalized double-wall CNTs that form many individualized, parallel pathways between two electrodes. Each carrier that travels across the electrodes is forced to take one of these pathways that are fully gated chemically by the target-probe binding events. This sensor design allows us to electrically detect Lyme disease oligonucleotide biomarkers directly at the physiological high-salt concentrations, simultaneously achieving both ultrahigh sensitivity (as low as 1 fM) and detection speed (<15 s). This unexpectedly simple strategy may open opportunities for sensor designs to broadly achieve instant detection of trace biomarkers and real-time probing of biomolecular functions directly at their physiological states.

Double-wall sign because of intestinal perforation.

This study sought to describe the case of an 86-year-old man who presented to our hospital complaining of abdominal pain, abdominal distention, and loss of appetite for 4 days prior. This case suggests that an amount of accumulated air clearly highlights the intestinal wall, like a "double-wall sign," even when the patient is standing.

Effects of 4 Weeks of Variability of Practice Training in Padel Double Right Wall: A Randomized Controlled Trial.

This study aimed to analyze the effect of a variable practice training in the double wall right forehand by using wrist weights. Thirty-four experienced padel players participated in this study. Players were randomly distributed in two groups (control group [CG] and training group [TG]). The TG performed 1 month of variable training, induced by weighted wrist bands, twice a week, with the same number of sessions and volume of training as the CG. TG obtained significant difference in posttest measurements (effect size = 0.437) in terms of the number of successful shots compared to CG (effect size = 0.027). These findings showed a significant effect of the TG with respect to the CG. Results reinforce the role of variability in the exploration and reinforcement of motor learning.

Vibration Band Gap Characteristics of Two-Dimensional Periodic Double-Wall Grillages.

In this article, the wave finite element method (WFEM) is used to calculate the band gap characteristics of two-dimensional (2D) periodic double-wall grillages (DwGs), which are verified by the grillage model vibration measurement experiment and finite element calculation. To obtain the band gap characteristics of periodic DwGs, the finite element calculation model is established according to the lattice and energy band theory and the characteristic equation of the periodic unit cell under the given wave vector condition is solved based on Bloch theorem. Then, the frequency transfer functions of finite-length manufactured and finite element models are obtained to verify the band gap characteristics of periodic DwGs. Finally, the effects of material parameters and structural forms on band gap characteristics and transfer functions are analyzed, which can provide a reference for engineering structure vibration and noise reduction design.

Endoscopic treatment of periampullary duodenal duplication cysts in children: Four case reports and review of the literature.

BACKGROUND: Duodenal duplications are rare congenital anomalies of the gastrointestinal tract. As the periampullary variant is much rarer, literature is scant and only few authors have reported their experience in diagnosis and treatment, particularly with operative endoscopy. CASE SUMARY: To report our experience with the endoscopic treatment in a series of children with periampullary duodenal duplication cysts, focusing on the importance of obtaining an accurate preoperative anatomic assessment of the malformations. The pediatric periampullary duodenal duplication cyst literature is reviewed. We conducted a systematic review according to the PRISMA guidelines. The PubMed database was searched for original studies on "duodenal duplication", "periampullary duplication" or "endoscopic management" published since 1990, involving patients younger than 18 years of age. Eligible study designs were case report, case series and reviews. We analyzed the data and reported the results in table and text. Fifteen eligible articles met the inclusion criteria with 16 patients, and analysis was extended to our additional 4 cases. Median age at diagnosis was 13.5 years. Endoscopic treatment was performed in 10 (50%) patients, with only 2 registered complications. CONCLUSION: Periampullary duodenal duplication cysts in pediatric patients are very rare. Our experience suggests that an accurate preoperative assessment is critical. In the presence of sludge or stones inside the duplication, endoscopic retrograde cholangio-pancreatography is mandatory to demonstrate a communication with the biliary tree. Endoscopic treatment resulted in a safe, minimally invasive and effective treatment. In periampullary duodenal duplication cyst endoscopically treated children, long-term follow-up is still necessary considering the potential malignant transformation at the duplication site.

A CeCoOx Core/Nb2 O5 @TiO2 Double-Shell Nanocage Catalyst Demonstrates High Activity and Water Resistance for Catalytic Combustion of o-Dichlorobenzene.

A series of catalysts with different core-shell structures has been successfully prepared by a hydrothermal method. They consisted of CeCoOx @TiO2 (single shell), CeCoOx @Nb2 O5 (single shell) and CeCoOx @Nb2 O5 @TiO2 (double shell) core-shell nanocages and CeCoOx nanocages, in which CeCoOx was the core and TiO2 and Nb2 O5 were shells. The influence of the core-shell structure on the catalytic performance of o-dichlorobenzene was investigated by activity, water-resistance, and thermal stability tests as well as catalyst characterization. The temperatures corresponding to 90 % conversion of o-dichlorobenzene (T90 ) of CeCoOx , CeCoOx @TiO2 , CeCoOx @Nb2 O5 , and CeCoOx @Nb2 O5 @TiO2 catalysts were 415, 383, 362 and 367 °C, respectively. CeCoOx @Nb2 O5 exhibited excellent catalytic activity, mainly owing to the special core-shell structure, large specific surface area, abundant activity of Co3+ , Ce3+ , Nb5+ , strong reducibility, and more active oxygen vacancies. It can be seen that the Nb2 O5 coating can greatly improve the catalytic activity of the catalyst. In addition, due to the protective effect of the TiO2 shell on CeCoOx , CeCoOx @Nb2 O5 @TiO2 catalysts exhibited outstanding thermal and hydrothermal stability for 20 hours. The T90 of CeCoOx @Nb2 O5 @TiO2 was slightly lower than that of CeCoOx @Nb2 O5 , but it had higher stability and hydrothermal stability. Furthermore, possible reaction pathways involving the Mars-van-Krevelen (MvK) and Langmuir-Hinshelwood (L-H) models were deduced based on studies of the temperature-programmed desorption of O2 (O2 -TPD), X-ray photoelectron spectroscopy (XPS), and in situ diffuse reflectance FTIR spectroscopy (DRIFTS) characterization.

A short bevel needle with a very thin tip improves vein puncture performance of peripheral intravenous catheters: An experimental study.

BACKGROUND: Peripheral intravenous catheter placement is frequently unsuccessful at the first attempt. One suggested risk factor is a small vein size, because of the consequences of mechanical forces generated by the needle tip. We developed short bevel needles with a very thin tip and evaluated their puncture performance in two in vitro models. METHODS: Peripheral intravenous catheters with a new needle ground using the lancet method (experimental catheter (L)) or backcut method (experimental catheter (B)) were compared with a conventional peripheral intravenous catheter (Surshield Surflo®) in a penetration force test and a tube puncture test. Penetration forces were measured when peripheral intravenous catheters penetrated a polyethylene sheet. The tube puncture test was used to evaluate whether the peripheral intravenous catheters could puncture a polyvinyl chloride tube at two positions, at the center and at 0.5 mm from the center of the tube. RESULTS: Mean penetration forces at the needle tip produced by experimental catheters (L) (0.05 N) and (B) (0.04 N) were significantly lower than those produced by the conventional catheter (0.09 N) (p < 0.01). At the catheter tip, mean forces produced by experimental catheter (B) and the conventional catheter were 0.16 N and 0.26 N, respectively (p < 0.05). In the tube puncture test, the frequency at which the conventional catheter punctured the center-shifted site on the tube at an angle of 20° and speed of 50 mm/min was low (40%). In contrast, experimental catheters (L) and (B) were 100% successful at puncturing both the center and center-shifted sites at 20°. CONCLUSION: Puncture performance was comparable between the lancet-ground and backcut-ground needles except for penetration forces at the catheter tip. The experimental catheters produced lower penetration forces and induced puncture without target displacement at smaller angles compared with the conventional catheter. Therefore, optimization of the needle can prevent vein deformation and movement, which may increase the first-attempt success rate.

Test and Study of Pipe Pile Penetration in Cohesive Soil Using FBG Sensing Technology.

In order to examine the applicability of Fiber Bragg Grating (FBG) sensing technology in the static penetration of pipe piles, static penetration tests in clay were conducted using double-wall open and closed model pipe piles. The strain was measured using FBG sensors, and the plug height was measured using a cable displacement sensor. Using one open pile and two closed piles, the difference in pipe pile penetration was compared and analyzed. Based on FBG sensing technology and the strain data, the penetration characteristics of the pipe pile, such as axial force, lateral friction, and driving resistance were examined. Results showed that FBG sensing technology has superior testing performance for the pipe pile penetration process, can accurately reflect the strain time history of pipe piles, and can clearly reflect the penetration process of pipe piles with increasing penetration depth. In addition, the variation law of the characteristics of the jacked pile pile-soil interface was obtained. This test has significance for model tests and the engineering design of pipe piles.

Synthesis and controlled-release properties of chitosan/ß-Lactoglobulin nanoparticles as carriers for oral administration of epigallocatechin gallate.

A nano-sized double-walled carrier composed of chitosan and ß-lactoglobulin (ß-Lg) for oral administration of epigallocatechin gallate (EGCG) was developed to achieve a prolonged release of EGCG in the gastrointestinal tract. Carboxymethyl chitosan (CMC) solution was added dropwise to chitosan hydrochloride (CHC) containing EGCG to form a primary coating by ionic complexation. Subsequently, ß-Lg was added to create a secondary layer by ionic gelation. The obtained EGCG-loaded chitosan/ß-Lg nanoparticles had sizes between 100 and 500 nm and zeta potentials ranging from 10 to 35mV. FT-IR spectroscopy revealed a high number of hydrogen-bonding sites in the nanoparticles, which could incorporate EGCG, resulting in high encapsulation efficiency. EGCG incorporated in the primary coating was released slowly over time by diffusion from the swollen CMC-CHC matrix after the outer layer of ß-Lg was degraded in the intestinal fluid. The sustained-release property makes chitosan/ß-Lg nanoparticles an attractive candidate for effective delivery of EGCG.

Double-wall carbon nanotube-porphyrin supramolecular hybrid: synthesis and photophysical studies.

Double-wall carbon nanotubes (DWCNTs) with pyridyl units covalently attached to the external wall through isoxazolino linkers and carboxylic groups that have been esterified by pentyl chains are synthesized. The properties of these modified DWCNTs are then compared with an analogous sample based on single-wall carbon nanotubes (SWCNTs). Raman spectroscopy shows the presence of characteristic radial breathing mode vibrations, confirming that the samples partly retain the integrity of the nanotubes in the case of DWCNTs, including the internal and external nanotubes. Quantification of the pyridyl content for both samples (DWCNT and SWCNT derivatives) is based on X-ray photoelectron spectroscopy and thermogravimetric profiles, showing very similar substituent load. Both pyridyl-containing nanotubes (DWCNTs and SWCNTs) form a complex with zinc porphyrin (ZnP), as evidenced by the presence of two isosbestic points in the absorption spectra of the porphyrin upon addition of the pyridyl-functionalized nanotubes. Supramolecular complexes based on pyridyl-substituted DWCNTs and SWCNTs quench the emission and the triplet excited state identically, through an energy-transfer mechanism based on pre-assembly of the ground state. Thus, the presence of the intact inner wall in DWCNTs does not influence the quenching behavior, with respect to SWCNTs, for energy-transfer quenching with excited ZnP. These results sharply contrast with previous ones referring to electron-transfer quenching, in which the double-wall morphology of the nanotubes has been shown to considerably reduce the lifetime of charge separation, owing to faster electron mobility in DWCNTs compared to SWCNTs.

Controlled protein release from monodisperse biodegradable double-wall microspheres of controllable shell thickness.

Biodegradable polymer microparticles are promising delivery depots for protein therapeutics due to their relatively simple fabrication and facile administration. Double-wall microspheres (DWMS) comprising a core and shell made of two distinct polymers may provide enhanced control of the drug release profiles. Using precision particle fabrication (PPF) technology, monodisperse DWMS were fabricated with model protein bovine serum albumin (BSA)-loaded poly(lactide-co-glycolide) (PLG) core and drug-free poly(d,l-lactic acid) (PDLL) shell of uniform thickness. Monolithic single-wall microspheres were also fabricated to mimic the BSA-loaded PLG core. Using ethyl acetate and dichloromethane as shell- and core-phase solvents, respectively, BSA was encapsulated selectively in the core region within DWMS with higher loading and encapsulation efficiency compared to using dichloromethane as core and shell solvents. BSA in vitro release rates were retarded by the presence of the drug-free PDLL shell. Moreover, increasing PDLL shell thickness resulted in decreasing BSA release rate. With a 14-µm thick PDLL shell, an extended period of constant-rate release was achieved.

Sonography of multifocal hydatidosis involving lung and liver in a female child.

Hydatid disease, caused by Echinococcus granulosus, is a zoonotic infection encountered worldwide. Though involvement of the liver and lungs is quite common, pelvic involvement is rarely reported, with the incidence being 0.2-2.2 %. Ovarian and broad ligament hydatids are rare entities and are usually seen after rupture of a hepatic hydatid cyst. These cysts are usually asymptomatic, and a high index of clinical suspicion coupled with unequivocal imaging findings is required to make an accurate and timely diagnosis. We present a case of multifocal hydatid disease in a female child involving the lungs and liver and provide an account of the quintessential radiological findings.