Shallow Penetration Research Articles

Effects of 60-GHz millimeter waves on neurite outgrowth in PC12 cells using high-content screening

Technologies for wireless telecommunication systems using millimeter waves (MMW) will be widely deployed in the near future. Forthcoming applications in this band, especially around 60GHz, are mainly developed for high data-rate local and body-centric telecommunications. At those frequencies, electromagnetic radiations have a very shallow penetration into biological tissues, making skin keratinocytes, and free nerve endings of the upper dermis the main targets of MMW. Only a few studies assessed the impact of MMW on neuronal cells, and none of them investigated a possible effect on neuronal differentiation. We used a neuron-like cell line (PC12), which undergoes neuronal differentiation when treated with the neuronal growth factor (NGF). PC12 cells were exposed at 60.4GHz for 24h, at an incident power density averaged over the cell monolayer of 10mW/cm2. Using a large scale cell-by-cell analysis based on high-content screening microscopy approach, we assessed potential effects of MMW on PC12 neurite outgrowth and cytoskeleton protein expression. No differences were found in protein expression of the neuronal marker β3-tubulin nor in internal expression control β-tubulin. On the other hand, our data showed a slight increase, although insignificant, in neurite outgrowth, induced by MMW exposure. However, experimental controls demonstrated that this increase was related to heating.

High resolution analysis of oxidation in Ni-Fe-Cr alloys after exposure to 315 °C deaerated water with added hydrogen

Alloy 600 (Ni-16Cr-9Fe) and Alloy 800 (Fe-35Ni-23Cr) were exposed to simulated primary water at 315°C. Oxidation phenomena were studied using high resolution electron microscopy. Extensive intergranular oxidation was observed in Alloy 600. In Alloy 800, only shallow intergranular oxygen penetration was detected. The mechanism of intergranular embrittlement in Alloy 600 is likely analogous to internal oxidation. Internal oxidation may not apply to Alloy 800 due to the formation of external rather than internal oxides. Comparisons are made to previous experiments in high temperature hydrogenated steam to validate the latter’s use as an accelerated primary water simulant environment.

Needle-free injection of 5-aminolevulinic acid in photodynamic therapy for the treatment of non-melanoma skin cancer.

Photodynamic therapy (PDT) has been widely used in treatment for skin cancer. However, topical 5-aminolevulinic acid (ALA) in PDT demonstrates poor therapeutic effect due to its shallow penetration. And intralesional ALA-PDT can bring great pain. The purpose of this study was to evaluate the efficacy of PDT with needle-free injection of ALA in the treatment of nonmalignant skin tumors. 54 non-melanocytic malignant lesions of 54 subjects were treated with needle-free injection of 20% 5-ALA under occlusion for 1.5 hours, and irradiated with light dose of 100 J/cm(2) at 100 mW for 20 minutes. Evaluation of treatment efficacy was conducted at 2 week after treatment. 44 cases showed complete response with six cycles of PDT, three cases with seven cycles, and three cases with nine cycles. The remaining four cases failed to show complete response even with nine cycle of PDT. No case was reported to have recurrence in 6 months posttreatment. Only four cases experienced disease recurrence in 1 year posttreatment. The treatment with PDT using needle-free injection of 5-ALA appears to be effective and well tolerated with milder therapeutic pain and low recurrence rate. It can be proposed as an effective treatment alternative for non-melanoma skin cancer.

Effects of the lateral stress on the inner frictional resistance of pipe piles driven into sand

The inner frictional resistance of pipe piles depends on the degree of soil plugging. Many factors including pile diameter, lateral stress at the pile tip and geometrical conditions of piles could influence the soil plugging. In this paper, the effects of inner sleeves attached at the pile base on the inner frictional resistance are discussed, particularly highlighting the lateral stresses at the sleeve using small-scale steel pipe piles penetrated into a medium dense sandy ground. A closed-ended pile of the same diameter was also tested to compare it with similar open-ended piles. The results of incremental filling ratio (IFR) and plug length ratio (PLR) were also discussed. A simple method was also proposed to evaluate IFR and PLR for the sleeved piles since they have originally been defined for non-sleeved piles. The results of the IFR indicate that all the piles penetrated under partially-plugged or unplugged state producing smaller penetration resistance than a similar closed-ended pile. The results of the corrected IFR give a better indication of the soil plugging of the sleeved piles, particularly at shallow penetration depths. The results also suggest that the inner frictional resistance increase with the sleeve height. The results of the coefficient of lateral earth pressure, K h also indicate that K h increases with the sleeve height. The effects however become less significant at higher sleeve heights. Therefore, we can recommend the use of the inner sleeve as an improvement method to increase the bearing capacity of open-ended piles installed in sandy grounds.

X-Ray Induced Photodynamic Therapy: A Combination of Radiotherapy and Photodynamic Therapy.

Conventional photodynamic therapy (PDT)'s clinical application is limited by depth of penetration by light. To address the issue, we have recently developed X-ray induced photodynamic therapy (X-PDT) which utilizes X-ray as an energy source to activate a PDT process. In addition to breaking the shallow tissue penetration dogma, our studies found more efficient tumor cell killing with X-PDT than with radiotherapy (RT) alone. The mechanisms behind the cytotoxicity, however, have not been elucidated. In the present study, we investigate the mechanisms of action of X-PDT on cancer cells. Our results demonstrate that X-PDT is more than just a PDT derivative but is essentially a PDT and RT combination. The two modalities target different cellular components (cell membrane and DNA, respectively), leading to enhanced therapy effects. As a result, X-PDT not only reduces short-term viability of cancer cells but also their clonogenecity in the long-run. From this perspective, X-PDT can also be viewed as a unique radiosensitizing method, and as such it affords clear advantages over RT in tumor therapy, especially for radioresistant cells. This is demonstrated not only in vitro but also in vivo with H1299 tumors that were either subcutaneously inoculated or implanted into the lung of mice. These findings and advances are of great importance to the developments of X-PDT as a novel treatment modality against cancer.

Evaluation of Geometric Progression (GP) Buildup Factors using MCNP Codes (MCNP6.1 and MCNP5-1.60)

The gamma-ray buildup factors of three-dimensional point kernel code (QAD-CGGP) are re-evaluated by using MCNP codes (MCNP6.1 and MCNPX5-1.60) and ENDF/B-VI.8 photoatomic data, which cover an energy range of 0.015–15 MeV and an iron thickness of 0.5–40 Mean Free Path (MFP). These new data are fitted to the Geometric Progression (GP) fitting function and are then compared with ANS standard data equipped with QAD-CGGP. In addition, a simple benchmark calculation was performed to compare the QAD-CGGP results applied with new and existing buildup factors based on the MCNP codes. In the case of the buildup factors of low-energy gamma-rays, new data are evaluated to be about 5% higher than the existing data. In other cases, these new data present a similar trend based on the specific penetration depth, while existing data continuously increase beyond that depth. In a simple benchmark, the calculations using the existing data were slightly underestimated compared to the reference data at a deep penetration depth. On the other hand, the calculations with new data were stabilized with an increasing penetration depth, despite a slight overestimation at a shallow penetration depth.

Aerosols in healthy and emphysematous in silico pulmonary acinar rat models

There has been relatively little attention given on predicting particle deposition in the respiratory zone of the diseased lungs despite the high prevalence of chronic obstructive pulmonary disease (COPD). Increased alveolar volume and deterioration of alveolar septum, characteristic of emphysema, may alter the amount and location of particle deposition compared to healthy lungs, which is particularly important for toxic or therapeutic aerosols. In an attempt to shed new light on aerosol transport and deposition in emphysematous lungs, we performed numerical simulations in models of healthy and emphysematous acini motivated by recent experimental lobar-level data in rats (Oakes et al., 2014a). Compared to healthy acinar structures, models of emphysematous subacini were created by removing inter-septal alveolar walls and enhancing the alveolar volume in either a homogeneous or heterogeneous fashion. Flow waveforms and particle properties were implemented to match the experimental data. The occurrence of flow separation and recirculation within alveolar cavities was found in proximal generations of the healthy zones, in contrast to the radial-like airflows observed in the diseased regions. In agreement with experimental data, simulations point to particle deposition concentrations that are more heterogeneously distributed in the diseased models compared with the healthy one. Yet, simulations predicted less deposition in the emphysematous models in contrast to some experimental studies, a likely consequence due to the shallower penetration depths and modified flow topologies in disease compared to health. These spatial-temporal particle transport simulations provide new insight on deposition in the emphysematous acini and shed light on experimental observations.

The spatial distribution of particulate organic carbon and microorganisms on seamounts of the South West Indian Ridge

Abstract 1 The ecology and biogeochemistry of oceanic seamounts is not very well understood and explored. Pelagic ecosystems above the summits and flanks of seamounts have been observed to show different biological or biogeochemical properties to off-seamount areas, such as enhanced chlorophyll concentrations, a phenomenon referred to as the “seamount effect”. In addition, seamount biogeography has been hypothesised to be similar to islands where community structure differences in multiple organisms have been shown to change between seamounts and across frontal systems. We used elemental analysis, to measure particulate organic carbon (POC), and flow cytometry, to estimate abundance of microorganisms from above four seamounts (Coral, Melville, Middle of What and Atlantis) along the Southwest Indian Ridge (SWIR) from latitude 32.6°S to 41.3°S, longitude 57.1°E to 42.7°E. Samples were collected from the surface to the bottom using a CTD fitted with optical sensors. POC was predicted from models created from in-situ transmission (optical) data (cp). The high resolution predicted POC in the euphotic zone showed a heterogeneous distribution both above individual and between seamounts. The shallow penetration of two of the seamounts displayed an effect on the POC concentration in the euphotic zone depleting the layer around the summit. The transmission data showed higher concentrations of particles towards the surface, caused by primary production, and near to the seabed, probably resulting from re-suspension of sediments. The POC concentrations and microbial abundance were positively correlated to cp and fluctuated with particle abundance, with microorganisms accounting for ~50% of the observed POC. Based on non-metric multidimensional scaling it is clear that the microbial clusters strongly indicate three separate biological regimes associated with northeastern, central and southwestern zones of the section of the SWIR that was sampled. This biological zonation is associated with physical oceanographic boundaries represented by the Subtropical and Subantarctic Fronts, forming three distinct “biogeographical” regions.

Intensification of pretreatment and pressure leaching of copper anode slime by microwave radiation

The application of microwave irradiation for pretreatment of copper anode slime with high nickel content prior to pressure sulfuric acid leaching has been proposed. The microwave-assisted pretreatment is a rapid and efficient process. Through the technology of microwave assisted pretreatment-pressure leaching of copper anode slime, copper, tellurium, selenium and nickel are almost completely recovered. Under optimal conditions, the leaching efficiencies of copper, tellurium, selenium and nickel are 97.12%, 95.97%, 95.37% and 93.90%, respectively. The effect of microwave radiation on the temperature of copper anode slime and leaching solution is investigated. It is suggested that the enhancement on the recoveries of copper, tellurium and selenium can be attributed to the temperature gradient which is caused by shallow microwave penetration depth and super heating occurring at the solid-liquid interface. The kinetic study shows that the pressure leaching of copper anode slime, with and without microwave assisted pretreatment, are both controlled by chemical reactions on the surfaces of particles. It is found that the activation energy calculated for microwave-assisted pretreatment-pressure leaching (49.47 kJ/mol) is lower than that for pressure leaching which is without microwave assisted pretreatment (60.57 kJ/mol).

Ink Penetration of Uncoated Inkjet Paper and Impact on Printing Quality

This study investigated ink penetration through imaging technology, first by gray and contour mapping and then calculating the ink penetration depth by programing. Next, a series of further analyses were carried out, including average ink permeability, ink distributions, and printability of different uncoated inkjet paper with different parameters. The impact on ink penetration of the microstructure and hydrophilicity of the uncoated paper was also studied. The experimental results indicated that paper specimens with sizing agent were resistant to the ink, resulting in a slow and shallow ink penetration. Paper containing filler had a more hydrophilic surface and porous structure, leading to a faster and deeper ink penetration. However, the calendering operation could make the paper structure more compact and reduce the porosity and penetration depth. When an appropriate combination of sizing agent, filler content, and the calendering process was utilized, a more stable hue could be produced with improvements in optical density, saturation, and color.

Continuous flow synthesis of poly(methyl methacrylate) via a light‐mediated controlled radical polymerization

ABSTRACTControlled radical polymerizations have significantly impacted the field of polymer science by facilitating the synthesis of polymers with greater control over molecular weight, structure, and dispersity (Ð). As these synthetic techniques continue to evolve, more degrees of control can be realized via external regulation. Recent work has demonstrated external regulation of a controlled radical polymerization process with light using a photoredox Ir‐catalyst. While light offers many advantages as a stimulus for polymerization, scaling up presents unique challenges such as shallow and uneven penetration of light through the reaction medium, which negatively impacts the rate of polymerization. This work addresses some of the challenges associated with scaling up light‐mediated controlled radical polymerizations by employing a continuous flow microreactor and selecting appropriate reactor materials for oxygen sensitive reactions. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2693–2698

Biopolymer-Lipid Bilayer Interaction Modulates the Physical Properties of Liposomes: Mechanism and Structure.

This study was conducted to elucidate the conformational dependence of the modulating ability of chitosan, a positively charged biopolymer, on a new type of liposome composed of mixed lipids including egg yolk phosphatidylcholine (EYPC) and nonionic surfactant (Tween 80). Analysis of the dynamic and structure of bilayer membrane upon interaction with chitosan by fluorescence and electron paramagnetic resonance techniques demonstrated that, in addition to providing a physical barrier for the membrane surface, the adsorption of chitosan extended and crimped chains rigidified the lipid membrane. However, the decrease in relative microviscosity and order parameter suggested that the presence of chitosan coils disturbed the membrane organization. It was also noted that the increase of fluidity in the lipid bilayer center was not pronounced, indicating the shallow penetration of coils into the hydrophobic interior of bilayer. Microscopic observations revealed that chitosan adsorption not only affected the morphology of liposomes but also modulated the particle aggregation and fusion. Especially, a number of very heterogeneous particles were visualized, which tended to confirm the role of chitosan coils as a "polymeric surfactant". In addition to particle deformation, the membrane permeability was also tuned. These findings may provide a new perspective to understand the physiological functionality of biopolymer and design biopolymer-liposome composite structures as delivery systems for bioactive components.

Ichnology of a Paleopolar, River-Dominated, Shallow Marine Deltaic Succession in the Mackellar Sea: The Mackellar Formation (Lower Permian), Central Transantarctic Mountains, Antarctica

The Lower Permian Mackellar Formation in the Beardmore Glacier Area of the Central Transantarctic Mountains, Antarctica, was deposited between 80 and 85°S paleolatitude. Previous studies suggest that Mackellar Formation strata were deposited in either a large glacial lake or inland sea. Our study identified 30 ichnogenera from Turnabout Ridge and Buckley Island of which: 1) none are exclusively freshwater forms; 2) 20 ichnogenera are found in freshwater, brackish, and marine settings; and 3) 10 ichnogenera are exclusively found in marine settings. Combining ichnologic evidence with sedimentologic observations suggests that the Mackellar Formation was deposited in a river-dominated delta in a fully marine to brackish-marine setting. Trace-fossil associations are grouped into the Arenicolites–Phycodes, Lingulichnus, Arenicolites–Planolites, Kouphichnium, Phycodes–Teichichnus–Arenicolites, and Planolites–Teichichnus–Phycodes ichnocoenoses of a mixed Skolithos–Cruziana ichnofacies. These associations are characteristic of epi- and endobenthic worms arthropods, and mollusks, with the vast majority of the traces being diminutive in diameter and length, and exhibit shallow (≤10mm) penetration depths. These ichnocoenoses occur in paleoenvironments that include the prodelta, distal to proximal delta front including mouth bars, and subaqueous terminal distributary channels. The diminutive morphology, shallow penetration depth, low bed ichnodiversity, high overall ichnodiversity, and sedimentologic characteristics are indicative of benthic organisms in a marine deltaic environment with short-lived communities composed of small-bodied organisms stressed by high freshwater input and high sedimentation rates.

Preferential coupling of an incident wave to reflection eigenchannels of disordered media.

Light waves incident to a highly scattering medium are incapable of penetrating deep into the medium due to the multiple scattering process. This poses a fundamental limitation to optically imaging, sensing, and manipulating targets embedded in opaque scattering layers such as biological tissues. One strategy for mitigating the shallow wave penetration is to exploit eigenchannels with anomalously high transmittance existing in any scattering medium. However, finding such eigenchannels has been a challenging task due to the complexity of disordered media. Moreover, it is even more difficult to identify those eigenchannels from the practically relevant reflection geometry of measurements. In this Letter, we present an iterative wavefront control method that either minimizes or maximizes the total intensity of the reflected waves. We proved that this process led to the preferential coupling of incident wave to either low or high-reflection eigenchannels, and observed either enhanced or reduced wave transmission as a consequence. Since our approach is free from prior characterization measurements such as the recording of transmission matrix, and also able to keep up with sample perturbation, it is readily applicable to in vivo applications. Enhancing light penetration will help improving the working depth of optical sensing and treatment techniques.

Molecular Dynamics Simulation of Conformational Transition and Frictional Performance Modulation of Densely Packed Self-Assembled Monolayers Based on Electrostatic Stimulation.

Self-assembled monolayers (SAMs) terminated with functional end groups such as polyethylene glycols (PEG) have attracted considerable attention because of their unique and flexible structure that exhibits conformational transition under electrostatic stimulation. Molecular dynamics simulations are used to investigate the conformational transition and associated modulation of frictional performance of densely packed PEG-terminated SAMs subjected to electrical field stimulation. Previously reported empirical potentials and atomic charges were used to model the intrachain bonds and electrostatic and interchain interactions. Simulation results indicate that significant conformational transition is generated because of the electrostatic forces. Under positive electrical fields, PEG groups are compressed and twisted into the helical form, "gauche" state, whereas under negative electrical fields, PEG groups are stretched into the straight form, "all-trans" state. Such conformational transition may lead to substantial alteration of frictional response upon SAMs. By shallow penetration and sliding using a repulsive indenter, the SAMs under positive electrical fields exhibit a level of frictional response that is comparatively lower than those under zero and negative potentials, which may be attributed to reduced interchain space for deformation, limited conformational transition, and less energy absorption. The simulation results demonstrate that with appropriate selection of functional end groups attached to SAM backbone chains it is possible to modulate frictional performance of densely packed SAMs via electrostatic stimuli.

Ultra fast microwave-assisted leaching for the recovery of copper and tellurium from copper anode slime

The decomposition of copper anode slime heated by microwave energy in a sulfuric acid medium was investigated. Leaching experiments were carried out in a multi-mode cavity with microwave assistance. The leaching process parameters were optimized using response surface methodology (RSM). Under the optimized conditions, the leaching efficiencies of copper and tellurium were 99.56% ± 0.16% and 98.68% ± 0.12%, respectively. Meanwhile, a conventional leaching experiment was performed in order to evaluate the influence of microwave radiation. The mechanism of microwave-assisted leaching of copper anode slime was also investigated. In the results, the microwave technology is demonstrated to have a great potential to improve the leaching efficiency and reduce the leaching time. The enhanced recoveries of copper and tellurium are believed to result from the presence of a temperature gradient due to the shallow microwave penetration depth and the superheating at the solid-liquid interface.

A Near Infrared Light Triggered Hydrogenated Black TiO2 for Cancer Photothermal Therapy.

White TiO2 nanoparticles (NPs) have been widely used for cancer photodynamic therapy based on their ultraviolet light-triggered properties. To date, biomedical applications using white TiO2 NPs have been limited, since ultraviolet light is a well-known mutagen and shallow penetration. This work is the first report about hydrogenated black TiO2 (H-TiO2 ) NPs with near infrared absorption explored as photothermal agent for cancer photothermal therapy to circumvent the obstacle of ultraviolet light excitation. Here, it is shown that photothermal effect of H-TiO2 NPs can be attributed to their dramatically enhanced nonradiative recombination. After polyethylene glycol (PEG) coating, H-TiO2 -PEG NPs exhibit high photothermal conversion efficiency of 40.8%, and stable size distribution in serum solution. The toxicity and cancer therapy effect of H-TiO2 -PEG NPs are relative systemically evaluated in vitro and in vivo. The findings herein demonstrate that infrared-irradiated H-TiO2 -PEG NPs exhibit low toxicity, high efficiency as a photothermal agent for cancer therapy, and are promising for further biomedical applications.

Exploring anti-reflection modes in disordered media.

Sensing and manipulating targets hidden under scattering media are universal problems that take place in applications ranging from deep-tissue optical imaging to laser surgery. A major issue in these applications is the shallow light penetration caused by multiple scattering that reflects most of incident light. Although advances have been made to eliminate image distortion by a scattering medium, dealing with the light reflection has remained unchallenged. Here we present a method to minimize reflected intensity by finding and coupling light into the anti-reflection modes of a scattering medium. In doing so, we achieved more than a factor of 3 increase in light penetration. Our method of controlling reflected waves makes it readily applicable to in vivo applications in which detector sensors can only be positioned at the same side of illumination and will therefore lay the foundation of advancing the working depth of many existing optical imaging and treatment technologies.

가변 극성 알루미늄 아크 용접의 이론적 배경 고찰

Cleaning effect is well known mechanism of oxide layer removal in DCEP polarity. It is also known that DCEN has higher heat input efficiency than DCEP in GTAW process. Based on these two renowned arc theories, conventional variable polarity arc for aluminum welding was set up to have minimum DCEP and maximum DCEN duty ratio to achieve the highest heat input efficiency and weldability increase. However, recent several variable polarity GTA research papers reported unexpected result of proportional relationship between DCEP duty ratio and heat input. The authors also observed the same result then suggested combination of tunneling effect and random walk of cathode spot to fill up the gap between experiment and conventional arc theory. In this research, suggested combinational work of tunneling effect and rapid cathode spot changing is applied to another unexpected phenomena of variable polarity aluminum arc welding. From previous research, it is reported that wider oxide removal range, narrower bead width and shallower penetration depth are observed in thin oxide layered aluminum compared to the case of thick oxide. This result was reported for the first time and it was hard to explain the reason at that time therefore the inference by the authors was hardly acceptable. However, the suggested combinational theory successfully explains the result of the previous report in logical way.

Scratch Characteristics of ZnMgO Epilayers

Zn0.75Mg0.25O films were grown via metal organic vapor phase epitaxy on an M-plane sapphire substrate. We used nanoscratch tests to study the abrasive plow of the films; comparable cases of critical pileup were obtained on both sides of each scratch when the ramped load increased from 0 to 250 μN. The film showed a crack in the bulge edge between the groove at ramped loads of 1000 μN as well as full plastic deformation. The values of μ were 0.14, 0.33, 0.43, and 0.48 for the ramped loads of 250 μN and 0.22, 0.26, 0.28, and 0.33 for the ramped load of 1000 μN. We found that cracking dominated in the case of Zn0.75Mg0.25O films during plowing. Lower values of the coefficient of friction and shallower penetration depths were observed at RT, while higher values were observed in the annealed samples. It is suggested that higher growth temperatures induce lower bonding forces and reduce the shear resistances of Zn0.75Mg0.25O films.