Several Centimeters In Length Research Articles

High-Throughput Growth of Armored Perovskite Single Crystal Fibers for Pixelated Arrays.

The poor machinability of halide perovskite crystals severely hampered their practical applications. Here a high-throughput growth method is reported for armored perovskite single-crystal fibers (SCFs). The mold-embedded melt growth (MEG) method provides each SCF with a capillary quartz shell, thus guaranteeing their integrality when cutting and polishing. Hundreds of perovskite SCFs, exemplified by CsPbBr3, CsPbCl3, and CsPbBr2.5I0.5, with customized dimensions (inner diameters of 150-1000µm and length of several centimeters), are grown in one batch, with all the SCFs bearing homogeneity in shape, orientation, and optical/electronic properties. Versatile assembly protocols are proposed to directly integrate the SCFs into arrays. The assembled array detectors demonstrated low-level dark currents (< 1nA) with negligible drift, low detection limit (< 44.84nGys-1), and high sensitivity (61147µCGy-1cm-2). Moreover, the SCFs as isolated pixels are free of signal crosstalk while showing uniform X-ray photocurrents, which is in favor of high spatial resolution X-ray imaging. As both MEG and the assembly of SCFs involve none sophisticated processes limiting the scalable fabrication, the strategy is considered to meet the preconditions of high-throughput productions.

Feeding rate in adult Manduca sexta is unaffected by proboscis submersion depth.

Adult moths from framily Spingidae (i.e. hawkmoths or sphinx moths) commonly feed on flower nectar through an extended proboscis, often several centimeters in length and longer than the body of the moth. Feeding on a viscous liquid (nectar) through a long and narrow tube is a challenging fluid dynamic problem and the subject of long-running scientific investigation. Here we characterized the relationship between proboscis submergence depth and nectar drinking rate in Manduca sexta hawkmoths. Video recordings of moth feeding bouts were collected and neural networks were used to extract data by object localization, tracking the location of the nectar meniscus and moths' proboscis tips. We found that although feeding rates vary among bouts, the variation was not associated with proboscis submergence depth. These results show that despite the theoretical possibility of fluid uptake through the walls of the proboscis, such effects do not have a substantial effect on nectar uptake rate, and suggest that nectar must traverse the full length of the proboscis.

Surface stress can initiate environment-assisted fracture in metals.

Controlling environmental effects in surface plasticity/fracture of metals is of interest for areas as diverse as manufacturing processes, product performance, and structural safety. The key to controlling these effects is understanding the effect of adsorbates on surface energy (γ) and surface stress (f). While γ has been well studied, the role of surface stress has received much less attention. We characterize surface stress induced in metals by adsorption of organic monolayers. Linear alkanoic acids of varying chain length (3-18) are deposited by molecular self-assembly onto one side of an aluminum cantilever, several centimeters in length. The surface stress is estimated from in situ measurement of the cantilever deflection. We find that the organic adsorbates induce large surface stress of -4 to +30N/m. Furthermore, we show that f may be tuned by varying adsorbate-molecule chain length. The stress data explain beneficial embrittlement of metal surfaces by organic adsorbates in cutting and comminution processes, and point to a critical role, hitherto ignored, for f in environment assisted cracking (EAC) phenomena. Our results suggest opportunities for utilizing controlled environment-assisted fracture as an aid-fracture as a friend-to enhance material removal processes, apart from using surface stress itself as an experimental probe to explore various manifestations of EAC.

Pseudo-cubic trigonal pyrite from the Madan Pb–Zn ore field (Rhodope Massif, Bulgaria): morphology and twinning

Abstract. A new occurrence of pyrite crystals with rhombohedral habit, up to several centimeters in length, is described from the Madan Pb–Zn ore field (Rhodope Massif, south Bulgaria), where it constitutes a late pyrite generation. As observed in the past in other deposits, the ideal rhombohedron is derived from the pyritohedron by suppression of half of its faces (six “polar faces”) around a ternary axis. In studied crystals, together with six main “equatorial faces”, additional minor faces correspond to cube faces as well as polar faces. Such a dissymmetry indicates that the crystallographic point group of these crystals is 3‾, a subgroup of the eigensymmetry 3‾2/m of a rhombohedron taken as geometric face form. Twinning by metric merohedry confirms such a symmetry decrease and permits the definition of this type of pyrite as a dimorph of cubic pyrite, i.e., pseudo-cubic trigonal pyrite (pyrite-R). Twin operations belong to the set of symmetry operations absent in point group 3‾ relative to pyrite symmetry m3‾: reflection about the {100} plane or two-fold rotation about the &lt;100&gt; direction. Four twin types have been distinguished (name, chromatic point group): three contact twins (reflection, m′; rotation, 2′; trapezoidal, (m(2)m(2)2(2))(4)), as well as one penetration twin (crossed, 2′/m′). Composition planes always correspond to {100}, but there are two types of twin interfaces. More complex twinned samples may develop erratically during crystal growth. Other twin variations as well as genetic aspects of such a type of pyrite are discussed.

Cryo-ET reveals sarcomere structures at molecular resolution.

Muscles underpin movement and heart function. Individual muscle fibers can be very large syncytia of up to several centimeters in length and are comprised of the force-generating and load-bearing devices of muscles called sarcomeres. Contraction and relaxation of sarcomeres relies on the sliding between two types of filaments—the thin filament (comprising mainly F-actin, tropomyosin, and troponin) and the thick myosin filament. In addition, several other proteins are involved in the contraction mechanism and their mutational malfunction can lead to debilitating and even life-threatening diseases. In my presentation, I will explain how we managed to obtain high-resolution structures of native sarcomeres using cryo-electron tomography (cryo-ET). Our cryo-ET reconstructions reveal molecular details of the three-dimensional organization and interaction of actin and myosin in the A-band, I-band and Z-disc and demonstrate that α-actinin cross-links antiparallel actin filaments by forming doublets with 6 nm spacing. Structures of myosin, tropomyosin, actin, and nebulin at up to 4.5 Å further reveal two conformations of “double-headed” myosin, where the flexible orientation of the lever arm and light chains enable myosin not only to interact with the same actin filament, but also to split between two actin filaments. The structures provide high-resolution details of the interaction between nebulin and actin, demonstrating the stabilising role of nebulin. Unexpectedly, nebulin does not interact with myosin or tropomyosin, but with a troponin-T linker through two potential binding motifs on nebulin, explaining its regulatory role. Our results provide unexpected insights into the fundamental organization of vertebrate skeletal muscle and serve as a strong foundation for future investigations of muscle diseases.

Novel Approach for Management of Deep Space Neck Infections: a Case Report

When patients present with deep space neck infections, typically the treatment involves Incision and Drainage (I&amp;D) with an extraoral incision that could measure several centimeters in length, as well as antibiotic administration. While this approach is effective in managing these types of infections, it is not without limitations. Most notably, patients treated with I&amp;Ds often are subject to prolonged hospitalization due to sepsis and they complain of a permanent, unsightly scar in the facial or cervical region once healed. In this case report, a 28-year-old male patient presenting to the emergency room with a right mandibular space collection of suppuration is treated with a modified version of the Seldinger technique which provided adequate abscess drainage and a more cosmetically-pleasing outcome once healed. Furthermore, this patient was treated bedside under local anesthesia as opposed to in an operating room under general anesthesia. While this technique may not be indicated for every patient presenting with deep space neck infections, it is a less-invasive approach that was effective for this patient.

Broadband Meandered Thin-Film Lithium Niobate Modulator With Ultra-Low Half-Wave Voltage

Compact thin-film lithium niobate (TFLN) modulators with low half-wave voltage <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\pi }$ </tex-math></inline-formula> are highly desirable for many applications. In particular, modulators with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\pi }~\sim ~1$ </tex-math></inline-formula> V would allow direct driving by CMOS circuits, but they normally require a long modulation length of several centimeters. Folded TFLN modulators exhibit reduced <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\pi }$ </tex-math></inline-formula> together with a small device footprint. However, previously reported schemes suffer from complicated device fabrication procedure to maintain the relative direction of electric field with respect to the TFLN crystal polarization after electrode folding. In this work, a meandered X-cut TFLN Mach–Zehnder (MZ) modulator with specially designed capacitively-loaded traveling-wave electrodes (CL-TWEs) is demonstrated. Interdigitated T-rails are employed to reverse the electric field in the folded region for continuous accumulation of optical phase shift. Ultra-low <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\pi }$ </tex-math></inline-formula> of 1.08 V is achieved on an 8-mm-long modulator containing three-segments of 7-mm-long modulation sections, together with a 3-dB electro-optic bandwidth around 43 GHz. The broadband meandered modulator with ultra-low half-wave voltage as well as a compact footprint has the potential to be directly driven by CMOS electronics.

KHz Plasma Pencil

Recently several investigators reported on various devices of generating cold plasma jets at atmospheric pressure. A pulsed plasma source developed and reported, the plasma pencil, is one of them. This device is capable of generating a cold plasma plume several centimeters in length using a DC pulsed high voltage source. In this study, kHz alternative current voltage (18 kV-15 kHz) was applied to the electrodes similar to the electrode system of the plasma pencil instead of direct current pulse voltage and a 2-3 cm long plasma jet was produced in an air using the helium gas. This new plasma jet device named as the kHz plasma pencil. The jets produced by the kHz plasma pencil are as cold as room temperature. The optical emission spectrum of the jet of the kHz plasma pencil and the change of the jet length with the gas flow rate have been investigated. Unlike the plasma pencil, the kHz plasma pencil produces jet in two different regimes as filamentary and diffusive and it emits more radiation in the UV range. Preliminary results show that the dynamics of the kHz plasma pencil are also different from the plasma pencil. Keywords: atmospheric pressure cold plasma jet, kHz, plasma pencil, Emission spectrum.

Килогерцевый плазменный карандаш

Recently several investigators reported on various devices of generating cold plasma jets at atmospheric pressure. A pulsed plasma source developed and reported, “the plasma pencil”, is one of them. This device is capable of generating a cold plasma plume several centimeters in length using a DC pulsed high voltage source. In this study, kHz alternative current voltage (18 kV-15 kHz) was applied to the electrodes similar to the electrode system of the plasma pencil instead of direct current pulse voltage and a 2-3 cm long plasma jet was produced in an air using the helium gas. This new plasma jet device named as the “kHz plasma pencil”. The jets produced by the kHz plasma pencil are as cold as room temperature. The optical emission spectrum of the jet of the kHz plasma pencil and the change of the jet length with the gas flow rate have been investigated. Unlike the plasma pencil, the kHz plasma pencil produces jet in two different regimes as filamentary and diffusive and it emits more radiation in the UV range. Preliminary results show that the dynamics of the kHz plasma pencil are also different from the plasma pencil.

Microscopic imaging along tapered optical fibers by right-angle Rayleigh light scattering in linear and nonlinear regime.

The evolution of the light intensity along an optical waveguide is evaluated by analysing far-field right-angle Rayleigh light scattering. The method is based on point by point spectral mapping distributed along the optical waveguide with a micrometric spatial resolution given by a confocal microscope, a high spectral resolution given by a spectrometer, and a high signal-to-noise ratio given by a highly cooled detector. This non-destructive and non-invasive experimental method allows the observation of the general Rayleigh scattering profile of the optical waveguide in a nominal operation, i.e., whatever the power or the wavelength of the light source, and can be applied to micrometer-scale waveguides of several centimeters in length, for which the longitudinal characterization is challenging. Applied to a tapered optical fiber, called nanofiber, with submicrometer final diameter and several centimeters long, the method has proved its capacity to collect different optical characteristics such as optical losses, mode beatings, transition from core-cladding to cladding-air guidance for different modes, localization of punctual defects, leaking of high order modes no longer guided by the fiber. Furthermore, the experimental results are successfully compared to measurements provided by the state-of-the-art Optical Backscatter Reflectometer system, and to numerical simulations. Moreover, coupled to the spectral resolution of the spectrometer, the method have allowed the distributed measurements of the Raman cascading process along the nanofiber, for the first time to our knowledge. The experimental technique developed in this work is complementary to other characterization methods generally focused on the optical parameters of the waveguide input or output. This technique can also be extended to others waveguides whatever its geometry which represents a strong interest for deepen optical characterization of photonics waveguides, or for other optical regimes characterized by spectral evolution of the field propagating along the waveguide.

Uniformity of Thermoluminescence and Optically Stimulated Luminescence Signals Over the Length of Doped LiMgPO4 Crystal Rods Grown by Micro-Pulling-Down Method.

The purpose of this work was to systematically assess the distribution of thermoluminescence (TL) and optically stimulated luminescence (OSL) properties along the length of crystals grown by the micro-pulling-down method, in relation to the microstructure and distribution of activators. We analyzed lithium magnesium phosphate (LiMgPO4; LMP) crystals doped with terbium (Tb; 0.8 mol%) or with a combination of thulium (Tm; 0.8 mol% or 1.2 mol%) and boron (B; 10 mol%). Crystals of several centimeters in length and 3 mm in diameter were cut into 20–40 slices, depending on length. For each sample, TL glow curves and OSL decay curves were examined. Optical microscopy and scanning electron microscopy were used to assess the microstructure and elemental composition of several selected samples. Two-dimensional TL readouts were performed to identify the areas with higher and lower signal emission. Our study showed that there may be significant differences not only in LMP sensitivity along the crystal’s axis but also on the surface of the slice. The distribution of activators varies depending on the type of crystals and strongly affects luminescence properties.

Understanding baffle overloads observed in high-mirror configuration on Wendelstein 7-X

The operational regimes in the first divertor campaign of W7-X were limited by unexpectedly high heat loads on certain baffle tiles. In the high-mirror configuration, a permanent hotspot on the baffle plate was detected by the thermographic system, which was further confirmed during the post-campaign inspections of the plasma-facing components. The maximum heat load on three baffle tiles reached about 4.5 MW m−2, which was almost an order of magnitude above its designed value of 0.5 MW m−2. The paper presents a detailed analysis to understand how the baffle plate, which is originally designed to screen the recycling neutrals and is therefore hidden from the hot plasma, can receive such a high heat load - a level that is expected for target plates. Three main causes have been identified: 1) the three baffle tiles are radially only about 5 mm away from a main heat channel towards a target, which is much shorter than the radial power decay length of several centimeters derived from the thermographic measurements in this region; 2) the three baffle tiles are intersected with field-lines of about 30 m length, which are long enough to collect considerable amount of heat via cross-field transport; 3) the baffle tiles have locally large grazing angles. In addition, the analysis method shown in this paper is of general use to estimate the heat flows in shadow areas of targets and thus to evaluate heat loads on the potentially critical components occurring in these areas, especially required for the design of complex 3D divertors like the one in W7-X.

A GIANT POST AURICULAR CUTANEOUS HORN: A RARE CASE REPORT

A cutaneous (cornu cutaneum) horn is a rare lesion which usually appears in sun-exposed areas and is very uncommon. It is a conical&nbsp;projection of hyperkeratotic epidermis and can be from a few millimeters to several centimeters in length. Here, we present the case&nbsp;of a large “horn” of long duration, arising in the right postauricular region in a 32-years-old male. The lesion was carefully examined,&nbsp;evaluated, complete excision was done with adequate margins and the defect was closed with primary closure after mobilizing the&nbsp;skin flaps adequately. Histopathologic examination showed the skin with underlying epidermis and extensive hyperkeratosis with no&nbsp;malignant cells seen at the base of the horn. It is important to mention that horn itself, is not the most important issue, but rather the&nbsp;underlying condition, which may be malignant also, needs to be ruled out and addressed.

P2880Incidence and clinical relevance of oversensing due to extracardiac signals in subcutaneous implantable cardiac defibrillator (S-ICD)

Abstract Background S-ICD is an ICD system completely extrathoracic, composed of a generator in a left infra-axillary position and a parasternal lead. Arrhythmia detection is done by analyzing extracardiac signals registered in a dipole that is several centimeters in length, larger than in a transvenous ICD. Hence, it could potentially be more susceptible to external interference (eg. myopotentials or electromagnetic noise). Purpose To assess real-world incidence and clinical relevance of oversensing due to extracardiac signals (OES) in S-ICD. Methods Retrospective review of medical reports and remote monitoring system in two Spanish hospitals. Events were assessed by EHRA-certified specialists in cardiac devices. Differences in patients with OES were sought by univariate analysis using parametric or non-parametric methods according to sample characteristics. Results 117 patients since October 2014 were analyzed. 88 (75,2%) men, age at implant 49,1±13,8 years. Implants were indicated mainly in primary prevention (72; 61,5%), due to ischemic cardiomyopathy (52; 44,4%), NYHA functional class I-II (107; 91,5%). 24 (20,5%) had intraventricular conduction disorders (9 right bundle branch, 2 left, 13 delayed intraventricular conduction). Electrodes implanted mostly left parasternal (107; 91,5%). On implant, gain ×1 in 90 (96,7% cases with data registered; 24 cases not registered), SmartPass activated in every device with such tool available. Patients were followed-up for 1,9±1,2 years (maximum 4,2). 4 (3,4%) received appropriate shocks, 10 (8,5%) inappropriate: 3 OES, 3 T-wave oversensing, 3 voltage decrease (leading to SmartPass deactivation), 1 lead dysfunction. In 8 cases OES was identified (incidence 3,7 /100 patients/year): in 3 (37,5%) cases inappropriate shocks were delivered. OES occurred 1,9 (interquartile range, IQR, 0,9–2,9) years after implant. No differences in OES were found depending on sex, indication, S-ICD or lead model, lead position, intraventricular conduction disorders, detection vector at implant, number of suitable vectors at screening, tachycardia detection rate or SmartPass automatic deactivation during follow-up In 5 cases, a cause for OES was identified: 4 myopotentials, 1 interference from electric engine. Cases were managed by changing sensing vector (3), increasing tachycardia detection rate (2), watchful waiting (2, OES source unidentified) or providing instructions to the patient (1). No OES recurrence after 0,8 years (IQR 0,6–1,1). Example of OES Conclusions S-ICD has an incidence of OES of 3,7 cases /100 patients/year. OES can be successfully managed with a conservative approach.

Sensitivity-Enhanced Extrinsic Fabry-Perot Interferometric Fiber-Optic Microcavity Strain Sensor.

This study presents an extrinsic Fabry–Perot interferometric (EFPI) fiber-optic strain sensor with a very short cavity. The sensor consists of two vertically cut standard single-mode fibers (SMFs) and a glass capillary with a length of several centimeters. The two SMFs penetrate into the glass capillary and are fixed at its two ends with the use of ultraviolet (UV) curable adhesives. Based on the use of the lengthy glass capillary sensitive element, the strain sensitivity can be greatly enhanced. Experiments showed that the microcavity EPFI strain sensor with initial cavity lengths of 20 μm, 30 μm, and 40 μm, and a capillary length of 40 mm, can yield respective cavity length–strain sensitivities of 15.928 nm/με, 25.281 nm/με, and 40.178 nm/με, while its linearity was very close to unity for strain measurements spanning a range in excess of 3500 με. Furthermore, the strain–temperature cross-sensitivity was extremely low.

Source of shrimp’s tough body armor uncovered

If everyone you’re related to packs a powerful punch, you would be wise to avoid brawling with family members. The mantis shrimp, which sports a club-like appendage tough enough to crack clamshells, ought to follow that advice but doesn’t. These aggressive marine crustaceans, which grow to several centimeters in length, survive repeated body punches from relatives in tussles over territory thanks to highly effective belly armor. By combining microscopy and X-ray analyses with mechanical tests, researchers have determined how the protective organ known as a telson works so effectively (Adv. Funct. Mater. 2019, DOI: 10.1002/adfm.201902238). The findings may lead to new types of lightweight, impact-resistant materials for helmets, sports equipment, and other applications. A research group led by David Kisailus of the University of California, Riverside, compared the telsons of two types of mantis shrimp: more aggressive ones that smash their prey and less aggressive ones that spear their prey.

3433 Tissue Engineered Nigrostriatal Pathway as a Test-Bed for Evaluating Axonal Pathophysiology in Parkinson’s disease

OBJECTIVES/SPECIFIC AIMS: Selective loss of long-projecting neural circuitry is a common feature of many neurodegenerative diseases, such as the vulnerable nigrostriatal pathway in Parkinson’s disease (PD). Current in vitro approaches for studying disease development generally do not mimic complex anatomical features of the afflicted substrates such as long axonal pathways between stereotypical neural populations. Such exquisite features are not only crucial for neural systems function but may also contribute to the preferential vulnerability and pathophysiological progression of these structures in neurodegenerative disease. We have previously developed micro-tissue engineered neural networks to recapitulate the anatomy of long-projecting cortical axonal tracts encased in a tubular hydrogel.1 Recently, we have extended this work to include the first tissue-engineered nigrostriatal pathway that was anatomically-inspired to replicate the structure and function of the native pathway.2 Notably, this tissue-engineered brain pathway possesses three-dimensional (3D) structure, multicellular composition, and architecture of long axonal tracts between distinct neuronal populations. Therefore, in the current study we apply this system as a biofidelic test-bed for evaluating axonal pathway development, maturation, and pathophysiology. METHODS/STUDY POPULATION: Dopaminergic neurons from the ventral mesencephalon and medium spiny neurons (MSNs) from the striatum were separately isolated from rat embryos. Tissue-engineered nigrostriatal pathways were formed by initially seeding dopaminergic neuron aggregates at one end of hollow hydrogel micro-columns with a central extracellular matrix, collectively spanning up to several centimeters in length. Several days later, tissue-engineered MSN aggregate was seeded on the other end and was allowed to integrate. Immunocytochemistry (ICC) and confocal microscopy were used to assess health, cytoarchitecture, synaptic integration, and mitochondrial dynamics with stains that label cell nuclei (Hoechst) and mitochondria (MitoTracker Red) and antibodies that recognize axons (anti-β-tubulinIII), neurons/dendrites (anti-MAP2), dopaminergic neurons/axons (anti-tyrosine hydroxylase; TH), and MSNs (anti-DARPP-32). RESULTS/ANTICIPATED RESULTS: Seeding tubular micro-columns with dopaminergic neuronal aggregates resulted in unidirectional axonal extension, ultimately spanning &gt;5mm by 14 days in vitro. For constructs also seeded with Tissue-engineered, ICC confirmed the presence of the appropriate neuronal sub-types in the two aggregate populations, specifically TH+ dopaminergic neurons and DARPP-32+ MSNs. Moreover, confocal microscopy revealed extensive axonal-dendritic integration and synapse formation involving the dopaminergic axons and MSN somata/dendrites. Collectively, these constructs mimicked the general cytoarchitecture of the in vivo nigrostriatal pathway: a discrete population of dopaminergic neurons with long-projecting 3D axonal tracts that were synaptically integrated with a population of MSNs. Mitochondria structure along axonal tracts was also observed using MitoTracker staining, revealing dynamic intra-axonal mitochondrial motility in this system. Ongoing studies are evaluating real-time mitochondrial dynamics and axonal physiology in this tissue-engineered nigrostriatal pathway in vitro, under both baseline conditions as well as following the addition of exogenous α-Synuclein fibrils to model synucleinopathy in PD. DISCUSSION/SIGNIFICANCE OF IMPACT: This tissue-engineered nigrostriatal pathway provides an anatomically-inspired platform with neuronal-axonal architecture that structurally and functionally emulates the nigrostriatal pathway in vivo. We are applying this paradigm as a powerful in vitro test-bed for understanding mitochondrial activity and inter-axonal energetics pathways under homeostatic as well as PD pathological conditions. Successful demonstration will serve as proof-of-concept that this technique can be used to study mitochondria pathology in personalized constructs built using cells derived from PD patients in order to evaluate pharmacological therapies targeted at improving mitochondrial resiliency and fitness so as to delay and/or prevent dopaminergic axonal/neuronal degeneration in tailored to specific PD patients.

Analysis of viscosity data in As2Se3, Se and Se95Te5 chalcogenide melts using the pressure assisted melt filling technique

The pressure-assisted melt filling technique (PAMFT) is promising approach for integrating new materials such as glasses or semiconductor into fiber, while only a small amount of starting material (<0.1 mg) is actually required for the implementation of such hybrid optical fibers of length of several centimeters. PAMFT has also the capability to provide viscosity data of glass-forming melts determined during the filling process. The main advantage of this technique – the demand of only small amounts of material (<0.1 mg) is accompanied by the fact that the molten material is encapsulated inside a silica capillary under high pressure. Therefore, PAMFT represents a promising method for measuring highly volatile and corrosive materials, such as chalcogenides. Here we present a detailed analysis on applying PAMFT for viscosity measurement of chosen chalcogenide systems with respect to experimental conditions (applied pressure and capillary diameter) and physical materials properties (surface tension and contact angle towards silica glass). For our study, we chose two well-known chalcogenide materials (Se and As2Se3) as representatives of non-wetting and wetting liquids towards silica glass. The melt viscosities were measured in the range of 0.01–25 Pa·s showing that PAMFT is a suitable method for the determination of viscosity of chalcogenide melts providing reliable data even if in the situation the influence of surface tension and contact angle is neglected. We also present new viscosity data on Se95Te5 chalcogenide melt obtained using PAMFT.

Non-thermal air plasma jets at atmospheric pressure: The flow-dependent propagation in the afterglow

With a bare pin-to-nozzle electrode configuration, an ac-driven non-thermal air plasma jet with a length of several centimeters is generated. Depending on the gas flow rate, the propagation speed of these plasma columns is in the range of 100–350 m/s, which is close to the gas flow velocity. This indicates that the propagation of the plasma jet is determined by the transport of long lifetime species by gas flow instead of the electron-impact excitation and ionization of molecules under a high electric field. In comparison to the N2, O2, and Ar plasma jets, the length of the air plasma jet is much shorter than that of the N2 plasma jet but longer than that of the O2 and Ar plasma jets. A simple kinetic model reveals that the N2 (A3Σ) metastable plays a crucial role in sustaining the length of the N2 and air plasma jets, whose lifetime is strongly dependent on the quenching effect of O2, O, and NO as well as the compensation from the three-body recombination of nitrogen atoms. Based on the flow-dependent mechanism of the plasma jet, a visually uniform air plasma brush with a width of 2.8 cm and a length of 1.6 cm and a visually uniform N2 plasma brush with a width of 4 cm and a length of 4.4 cm have been demonstrated.

The Light at the End of the Tunnel

Roughly 5-10% of common bile duct (CBD) stones cannot be removed by conventional methods owing to alterated anatomy. Percutaneous transhepatic cholangioscopic lithotomy (PTCSL) has been cited as a viable alternative to these difficult situations. Because PTC is time consuming, more involved, and requires expertise it is an often underutilized technique for stone removal. We present to you a case of PTSCL in the setting of a complex clinical situation. A 69 year old female with a history of Roux-En-Y surgery presented with a 3 week history of abdominal pain and jaundice. Her labs revealed a total bilirubin of 5.3 mg/dL. Alkaline phosphatase 1293 mg/dL, ALT 79 mg/dL, and AST 121 mg/dL. On a CT scan she had a intraductal polypoid lesion 1.7 x 2 x 1.8 cm obstructing the CBD with 1.7cm dilation. She underwent single balloon ERCP however cannulation of the CBD was unsuccessful. A PTC drain was placed and a cholangiogram revealed severe biliary ductal dilation with a polypoid filling defect within the inferior CBD. The patient then returned to the hospital with sepsis from multiple sources including C. Diff, UTI, and peritonitis. Because of her clinical condition she was not deemed to be a surgical candidate and thus she underwent cholangioscopic examination via her PTC drain. A 12 French sheath was advanced over a wire into the common bile duct to the level of the abrupt cut off. A cholangioscope was advanced and demonstrated an obstructing stone measuring approximately 25 mm in diameter and several centimeters in length. Lithotripsy was then performed shattering the stone. The ampulla was then balloon dilated and a balloon was then used to push the contents within the common bile duct into the small bowel. This was process was repeated several times with serial dilations of the ampulla. The patient improved and was sent home. Though PTCSL is a challenging procedure, it is an alternative to conventional methods for several reasons. In groups who are experienced with PTC, the rate of successful stone removal is close to 90%. In addition, the complication rates can be equivocal to ERCP complications, and less than laparoscopic assisted techniques. Finally, cholangioscopy does not require dilation of the biliary tree making this procedure advantageous in comparison to other techniques. This case serves to corroborate the efforts of other case series showing PTCSL to be an enticing alternative to removing CBD stones in patients with surgically altered anatomy.1374_A.tif Figure 1: CBD obstruction1374_B.tif Figure 2: CBD obstruction1374_C.tif Figure 3: Dr. Mizrahi using SpyGlass