Local Cavity Research Articles

Effect of underwater local cavity welding method conditions on diffusible hydrogen content in deposited metal

One of the methods with great potential for applications in underwater repairs is local cavity welding. In local cavity method, cooling conditions and diffusible hydrogen amount in weld metal are nearly the same as those existed during welding in the air. This paper presents the results of literature survey and preliminary tests of the effect of local cavity welding conditions on diffusible hydrogen amount in a deposited metal. A Plackett–Burman design was applied to screen seven parameters: thickness of elastic cover, stick-out of electrode wire, welding current, voltage, travel speed of welding, salinity of water, and flow rate of shielding gas.

The Local Defect Effect on Molecular Local Density State in Carbon Diamond Structures

The effect of local molecular structural cavity defect on the atom frequencies of bonded atoms is investigated in this study. The molecular dynamic (MD) simulation method is used to simulate the variation of atom frequency near by the cavity defect in a carbon diamond structure. The potential energy model, i.e. the second-generation reactive empirical bond order (REBO) potential function, is employed to derive the dynamic interaction between bonded atoms. The effect of local defect on the vibration amplitude and the density of state (DOS) is studied. The simulated results indicate that the local defect may affect the dynamic behavior of atoms near the local cavity defect significantly.

Post-operative Pain Analysis between Single Visit and Two Visit Root Canal Treatments using Visual Analogue Scale: An In Vivo Study

The purpose of this clinical study was to evaluate post-operative pain, after root canal therapy, performed in one appointment versus two appointment using calcium hydroxide intracanal medicament. Study design: In this in-vivo study, 60 patients requiring root canal therapy on permanent 1st molars were included. Patients were randomly divided into two experimental and one control group. Group1: One visit therapy (n=20) Group2: Two visit therapy with 1 week of calcium hydroxide dressing (n=20) Group3(Control): Two visit therapy with 1 week of sterile dry cotton pellet dressing (n=20) Materials and method : The standard protocol for all the patients included local anaesthesia, isolation & access cavity preparation, chemomechanical preparation with Rotary Protaper NiTi instruments, and irrigation with 3% sodium hypochlorite, 17% EDTA, 0.9%saline and 2% chlorhexidine. Teeth in group1 (n=20) were obturated on the same appointment using single cone technique (6% gutta percha points) and AH Plus sealer. Teeth in group 2(n=20) and group 3(n=20) were given a dressing of calcium hydroxide and dry cotton pellet respectively for a week followed by double seal with Cavit G and IRM. These teeth were obturated on the 2nd appointment using same material and techniques as in group 1. Teeth in all three groups were restored with dual cure composite resin. A modified Visual Analogue Scale was used to measure preoperative pain and postoperative pain after 6, 12, 24 & 48hrs interval. Statistical analysis was performed using an independent-sample t test. There was no statistically significant difference between groups at any of the four postoperative intervals. There was no significant difference among all the three groups studied after 12, 24hrs & 48hrs. Conclusion : Within the limitations of this in vivo study, it may be concluded that Single Visit Endodontics provides excellent results, if care in diagnosis and proper case selection is given importance. Calcium hydroxide has no relation in eliminating or reducing postoperative pain.

Risk of Leptomeningeal Disease in Patients Treated With Stereotactic Radiosurgery Targeting the Postoperative Resection Cavity for Brain Metastases

We sought to determine the risk of LMD in patients treated with stereotactic radiosurgery (SRS) targeting the post-operative cavity following surgical resection of a brain metastasis, deferring whole brain irradiation in all patients. We retrospectively reviewed 161 brain metastasis resection cavities in 153 patients treated from 1998 to 2011 with post-operative SRS. No patient had prior WBI. LMD was defined through radiologic and/or pathologic findings. The Kaplan-Meier overall survival, local cavity, distant parenchymal brain and distant LMD brain failure rates were calculated. Control rates were censored at the time of last follow-up or at the time of salvage whole brain irradiation. Statistically significant factors associated with LMD were determined through univariate analysis. Factors analyzed included: Histology (Lung, Colon, Breast, Melanoma, Gynecologic, Other), location of tumor at the pial surface (Yes vs. No), posterior fossa versus supratentorial location, en bloc versus piecemeal/indeterminate resection. Median follow-up was 12 months (range 1-114 months). Median overall survival was 18 months (range 1-114 months). Local cavity control at 1 and 2 years was 87% and 81%. Eighteen patients (11% of cavities) developed LMD at a median of 5 months (range 2-33 months) following SRS. Five of 18 were isolated LMD failures; 13 of 18 had additional new parenchymal metastases. The 1 and 2 year risk of LMD was 13%. Posterior fossa (p = 0.4) or pial (p = 0.4) location were not associated with LMD. The only factor predictive for LMD on univariate analysis was breast cancer histology (p = 0.002). Thirty-three percent (8 of 24) of breast cancer cavities developed LMD compared to 7% (10 of 137) other histology for a 1 year rate of LMD of 34% for breast versus 9% for non-breast histology. All LMD patients received WBI. Median survival following the diagnosis of LMD was 7 months (range 1-37 months). Patients treated with SRS targeting the post-operative cavity following resection of breast cancer metastases have a high risk of LMD in this series. Post-operative whole brain irradiation or novel strategies such as pre-operative SRS should be considered in this patient population.

Research on plasma resonances and optical forces between two cylindrical silver nanowires

Plasma resonance and optical forces between two cylindrical silver nanowires are studied theoretically. We analyze the negative optical forces effect in detail with the varying relative position and size of the two silver nanowires. It is found that the optical forces between the two nanowires can change with the gap distance and the inner diameters of wires. The negative optical force, indicating attractive between two cylindrical silver nanowires with the local cavity coupled plasma resonance mode inside the air gap. And the electric field is mostly located inside the air gap with the cavity local resonance effect. The negative optical pressure is driven by the kinetic energy of the conduction electrons inside the metallic cavity walls. The positive optical force indicates repulsive between the two cylindrical silver nanowires as like the electromagnetic wave transmits from one nanowire to another nanowire.

Interstellar reddening towards six small areas in Puppis-Vela

We investigate the distribution of the interstellar dust towards six small volumes of the sky in the region of the Gum nebula. New high-quality four-colour uvby and H\beta\ Str\"omgren photometry obtained for 352 stars in six selected areas of Kapteyn, complemented with data obtained in a previous investigation for two of these areas, were used to estimate the colour excess and distance to these objects. The obtained colour excess versus distance diagrams, complemented with other information, when available, were analysed in order to infer the properties of the interstellar medium permeating the observed volumes. On the basis of the overall standard deviation in the photometric measurements, we estimate that colour excesses and distances are determined with an accuracy of 0.010 mag and better than 30%, respectively, for a sample of 520 stars. A comparison with 37 stars in common with the new Hipparcos catalogue attests to the high quality of the photometric distance determination. The obtained colour excess versus distance diagrams testify to the low density volume towards the observed lines-of-sight. Very few stars out to distances of 1 kpc from the Sun have colour excesses larger than E(b-y) = 0.1 mag. In spite of the low density character of the interstellar medium towards the Puppis-Vela direction, the obtained reddening as a function of the distance indicates that two or more interstellar structures are crossed towards the observed lines-of-sight. One of these structures may be associated with the very low density wall of the Local Cavity, which has a distance of 100-150 pc from the Sun. Another structure might be related to the Gum nebula, and if so, its front face would be located at about 350 pc from the Sun.

Interstellar Gas in the Local Chimneys

ABSTRACTWe present ultraviolet absorption observations of four nearby (d < 250 pc) DA white dwarfs using spectral data (R ∼ 15 km s-1) obtained with the NASA HST Cosmic Origins Spectrograph (1150–1700 Å) and the Far Ultraviolet Spectroscopic Explorer (912–1170 Å). Two of these targets (WD2321 - 549 and WD2124 - 224) sample gas along the Southern Local Chimney sight line, while WD1040 + 492 samples gas within the Northern Local Chimney and the sight line toward WD2257 - 073 samples gas located entirely within the central confines of the Local Interstellar Cavity. We have fit the numerous high and low ion interstellar absorption-line profiles with theoretical models in order to determine the velocity and ion column densities of the sight-line gas clouds. Using these data we have derived element abundances relative to that of (assumed undepleted) sulfur for each of the four sight lines. We find that the 89 pc sight line toward WD2257 - 73 reveals a pattern of element depletion associated with interstellar gas located within the inner Local Cavity that is greater than those derived for the other three sight lines that sample gas within the two Local Chimney features. The sight lines toward WD2124 - 224 and WD2321 - 549, which sample gas along the Southern Local Chimney, show patterns of element depletion that are greater than that derived for the Northern Local Chimney sight line toward WD1040 + 492. Although our sight line sample is small, these data seem to indicate that the interstellar gas located along both local chimneys may be chemically different from gas within the central regions of the Local Cavity. This may indicate that Local Chimney gas has a different physical history and origin from the interstellar gas located within the inner Local Cavity.

Vibronic spectra of single dibenzoterrylene molecules in anthracene and 2,3-dimethylanthracene crystals

The vibronic structure of fluorescence excitation spectra of single molecules of dibenzoterrylene (DBT) in anthracene (Ac) and in 2,3-dimethylanthracene (2,3-DMA) crystals were studied at 5K. The vibronic patterns observed for different single molecules in the same crystal site were explained as fingerprints of the molecular geometry, which according to the ONIOM calculations are strongly dependent on the local insertion cavity. The ‘dipolar’ disorder encountered in the 2,3-DMA crystals led to a broad frequency distribution of the purely electronic lines of single molecules. The saturation curves for the (0,0) and vibronic transitions were studied.

A novel approach for the treatment of pelvic abscess: transrectal endoscopic drainage facilitated by transanal endoscopic microsurgery access

Postoperative pelvic abscesses in patients submitted to colorectal surgery are challenging. The surgical approach may be too risky, and image-guided drainage often is difficult due to the complex anatomy of the pelvis. This article describes novel access for drainage of a pelvic collection using a minimally invasive natural orifice approach. A 37 year-old man presented with sepsis due to a pelvic abscess during the second postoperative week after a Hartmann procedure due to perforated rectal cancer. Percutaneous drainage was determined by computed tomography to be unsuccessful, and another operation was considered to be hazardous. Because the pelvic fluid was very close to the rectal stump, transrectal drainage was planned. The rectal stump was opened using transanal endoscopic microsurgery (TEM) instruments. The endoscope was advanced through the TEM working channel and the rectal stump opening, accessing the abdominal cavity and pelvic collection. The pelvic collection was endoscopically drained and the local cavity washed with saline through the scope channel. A Foley catheter was placed in the rectal stump. The patient's recovery after the procedure was successful, without the need for further intervention. Transrectal endoscopic drainage may be an option for selected cases of pelvic fluid collection in patients submitted to Hartmann's procedure. The technique allows not only fluid drainage but also visualization of the local cavity, cleavage of multiloculated abscesses, and saline irrigation if necessary. The use of TEM instrumentation allows safe access to the peritoneal cavity.

Co-administration of attenuated Mycoplasma hyopneumoniae 168 strain with bacterial DNA enhances the local and systemic immune response after intranasal vaccination in pigs

Mycoplasma hyopneumoniae, the primary pathogen of enzootic pneumonia, occurs worldwide and causes major economic losses to the pig industry. M. hyopneumoniae infects pigs at mucosal surfaces of respiratory tract. The aim of the present study was to investigate if the protection rate against M. hyopneumoniae infection following intranasal immunization with attenuated M. hyopneumoniae 168 strain is improved by administration of bacterial DNA containing CpG motifs. Thirty pigs were immunized intranasally or intramuscularly and the levels of local respiratory tract and systemic immune responses were detected. The results showed that the number of intraepithelial lymphocytes in the tracheal fork, the levels of cytokine IL-6, and M. hyopneumoniae specific SIgA in local nasal cavity increased respectively after intranasal vaccination with the attenuated M. hyopneumoniae 168 strain alone. However, the levels of IL-10 and IFN-γ in local nasal cavity, the number of intraepithelial lymphocytes in trachea, CD4(+) and CD8(+) T lymphocytes in the lung and hilar lymph nodes, the specific IgG antibody level in serum on 35 day post immunization were all increased significantly after intranasal vaccination of the attenuated M. hyopneumoniae 168 strain adjuvanted with bacterial DNA. We concluded that intranasal administration of attenuated M. hyopneumoniae 168 strain adjuvanted with bacterial DNA may be effective in evoking the local cellular and humoral immune response in the respiratory tract and the systemic immune response. Intranasal vaccination will be effective in prevention of the transmission and prevalence of MPS.

原子与耦合腔相互作用系统中的纠缠特性

The two-excitation system comprising two two-level atoms resonantly interacting with two coupled cavities is analyzed.The evolution of the state vector of the system is given when the total excitation number equals two.By means of the numerical calculations,the temporal evolution in the entanglement is investigated between the atoms,between the cavities,as well as between the atom and the local cavity mode.The influences of coupling constant between cavities on the entanglements are discussed.The results obtained show that atom and atom are separable,and the cavity-cavity entanglement and the atom-cavity entanglement are weakened with increasing of the coupling constant between cavities.

Underwater Welding of Duplex Stainless Steel

The present work was conducted to assess the weldability of duplex stainless steel at underwater conditions. Interest of underwater welding of this steel grade is connected with necessity of preparing welding repair technologies for subsea pipelines widely used in offshore oil and gas industry. The GMA local cavity welding method was used in the investigations. Welded beads were performed underwater at 0.5 m depth and in the air. Metallographic examinations of welds, ferrite content assessment in microstructure and hardness test were performed. The good weldability at underwater conditions of duplex stainless with the use of GMA local cavity method was confirmed.

Cofactor‐binding sites in proteins of deviating sequence: Comparative analysis and clustering in torsion angle, cavity, and fold space

Small molecules are recognized in protein-binding pockets through surface-exposed physicochemical properties. To optimize binding, they have to adopt a conformation corresponding to a local energy minimum within the formed protein-ligand complex. However, their conformational flexibility makes them competent to bind not only to homologous proteins of the same family but also to proteins of remote similarity with respect to the shape of the binding pockets and folding pattern. Considering drug action, such observations can give rise to unexpected and undesired cross reactivity. In this study, datasets of six different cofactors (ADP, ATP, NAD(P)(H), FAD, and acetyl CoA, sharing an adenosine diphosphate moiety as common substructure), observed in multiple crystal structures of protein-cofactor complexes exhibiting sequence identity below 25%, have been analyzed for the conformational properties of the bound ligands, the distribution of physicochemical properties in the accommodating protein-binding pockets, and the local folding patterns next to the cofactor-binding site. State-of-the-art clustering techniques have been applied to group the different protein-cofactor complexes in the different spaces. Interestingly, clustering in cavity (Cavbase) and fold space (DALI) reveals virtually the same data structuring. Remarkable relationships can be found among the different spaces. They provide information on how conformations are conserved across the host proteins and which distinct local cavity and fold motifs recognize the different portions of the cofactors. In those cases, where different cofactors are found to be accommodated in a similar fashion to the same fold motifs, only a commonly shared substructure of the cofactors is used for the recognition process.

USING M DWARF SPECTRA TO MAP EXTINCTION IN THE LOCAL GALAXY

We use spectra of more than 56,000 M dwarfs from the Sloan Digital Sky Survey (SDSS) to create a high-latitude extinction map of the local Galaxy. Our technique compares spectra from the stars in the SDSS Data Release 7 M dwarf sample in low-extinction lines of sight, as determined by Schlegel, Finkbeiner, & Davis, to other SDSS M dwarf spectra in order to derive improved distance estimates and accurate line-of-sight extinctions. Unlike most previous studies, which have used a two-color method to determine extinction, we fit extinction curves to fluxes across the entire spectral range from 5700 to 9200 {\AA} for every star in our sample. Our result is an extinction map that extends from a few tens of pc to approximately 2 kpc away from the sun. We also use a similar technique to create a map of R_V values within approximately 1 kpc of the sun, and find they are consistent with the widely accepted diffuse interstellar medium value of 3.1. Using our extinction data, we derive a dust scale height for the local galaxy of 119\pm15 parsecs and find evidence for a local dust cavity.

THE LOCAL LEO COLD CLOUD AND NEW LIMITS ON A LOCAL HOT BUBBLE

We present a multi-wavelength study of the local Leo cold cloud (LLCC), a very nearby, very cold cloud in the interstellar medium. Through stellar absorption studies we find that the LLCC is between 11.3 pc and 24.3 pc away, making it the closest known cold neutral medium cloud and well within the boundaries of the local cavity. Observations of the cloud in the 21-cm HI line reveal that the LLCC is very cold, with temperatures ranging from 15 K to 30 K, and is best fit with a model composed of two colliding components. The cloud has associated 100 micron thermal dust emission, pointing to a somewhat low dust-to-gas ratio of 48 x 10^-22 MJy sr^-1 cm^2. We find that the LLCC is too far away to be generated by the collision among the nearby complex of local interstellar clouds, but that the small relative velocities indicate that the LLCC is somehow related to these clouds. We use the LLCC to conduct a shadowing experiment in 1/4 keV X-rays, allowing us to differentiate between different possible origins for the observed soft X-ray background. We find that a local hot bubble model alone cannot account for the low-latitude soft X-ray background, but that isotropic emission from solar wind charge exchange does reproduce our data. In a combined local hot bubble and solar wind charge exchange scenario, we rule out emission from a local hot bubble with an 1/4 keV emissivity greater than 1.1 Snowdens / pc at 3 sigma, 4 times lower than previous estimates. This result dramatically changes our perspective on our local interstellar medium.

Exploring Novel Approaches to Vaginal Drug Delivery

Vaginal route serves as a potential site of drug administration for local and systemic absorption of a variety of therapeutic agents. Despite being a non- invasive route of drug administration, the vagina has not been extensively explored as compared to other routes. Intravaginal drug delivery has been traditionally restricted to delivery of antinfectives to the local vaginal cavity. Concerted efforts have been made in the recent past to rediscover the vaginal route as a potential route for the delivery of therapeutically important molecules, proteins, peptides, small interfering RNAs, oligonucleotides, antigens, vaccines and hormones. The understanding of vaginal physiology has led to the design of specific intravaginal drug delivery systems to reach the systemic circulation. To overcome the limitations of conventional dosage forms administered through vaginal route various novel approaches like the use of mucoadhesive or bioadhesive polymers, pH- or temperature-sensitive polymers, liposomes, nanoemulsions, nanoparticles, vaginal inserts, multiple emulsions and hydrogels have been designed which enable controlled and prolonged release of drugs. The present article is a comprehensive review of the research and patents encompassing conventional dosage forms used for vaginal drug delivery with emphasis on newer platform technologies pertaining to intravaginal administration.

Trapping and releasing light by mechanical implementation in metamaterial waveguides

We show that light trapping and releasing can be switched by a mechanic tuning effect in metamaterial waveguides. The transition mechanism between the trapping and releasing states relies on the synergetic effect of the local Bragg reflection and cavity resonance in the waveguides. As a proof-of-concept demonstration, a heterostructured metamaterial waveguide comprised of dielectric claddings and a tapered metamaterial core formed by arrays of metal slats is analytically and numerically investigated. The spatial separation of the trapped light with various frequencies and the transition between the trapping and releasing states can be predicted by a "rainbow equation." The proposed light trapping and releasing scheme based on the mechanical implementation of waveguide geometrical parameters can be exploited to develop opto-mechanical devices for slow light technology.

The Entanglement Properties Induced by Atoms in Two Separate Cavities Connected by an Optical Fiber

We study the entanglement evolution between two atoms, which are initially entangled with a third atom and trapped in two separated cavities coupled by an optical fiber. We also investigate the temporal evolution in the entanglement between the atom and the local cavity mode. The influence of the state-selective measurement on the atom outside the cavities and the influence of cavity-fiber coupling coefficient on the entanglement are discussed. The results show that the entanglement can be strengthened through the state-selective measurement on the atom outside the cavities. We also find that, by increasing the cavity-fiber coupling coefficient, the atom-atom entanglement is strengthened, but the atom-cavity entanglement is weakened.

Numerical Analysis of Cavitation Flow during Vertical Water Exit of Underwater Vehicles

During water-exit of underwater vehicle, the high pressure， which the local cavity collapse of underwater vehicle causes, poses a great challenge to the vehicle structure. The cavity collapse during vertical water exit of an underwater vehicle is simulated by a viscous flow solver with homogeneous multiphase flow model. The shrinkage and collapse of cavity zone and violent changes of the pressure field have been captured during the simulation. The changes of cavity shape and pressure field at different water exit velocity have been analyzed. It has been concluded that higher velocity may cause the delay of cavity total collapse and the max pressure point to transfer backwards.

OPTICAL POLARIZATION MAPPING TOWARD THE INTERFACE BETWEEN THE LOCAL CAVITY AND LOOP I

The Sun is located inside an extremely low density and quite irregular volume of the interstellar medium, known as the Local Cavity (LC). It has been widely believed that some kind of interaction could be occurring between the LC and Loop I, a nearby superbubble seen in the direction of the Galactic Center. As a result of such interaction, a wall of neutral and dense material, surrounded by a ring shaped feature, would be formed at the interaction zone. Evidence of this structure was previously observed by analyzing the soft X-ray emission in the direction of Loop I. Our goal is to investigate the distance of the proposed annular region and map the geometry of the Galactic magnetic field in these directions. On that account, we have conducted an optical polarization survey to 878 stars from the Hipparcos catalogue. Our results suggest that the structure is highly twisted and fragmented, showing very discrepant distances along the annular region: approximately 100 pc to the left side and 250 pc to the right side, independently confirming the indication from a previous photometric analysis. In addition, the polarization vectors' orientation pattern along the ring also shows a widely different behavior toward both sides of the studied feature, running parallel to the ring contour in the left side and showing no relation to its direction in the right side. Altogether, these evidence suggest a highly irregular nature, casting some doubt on the existence of a unique large-scale ring-like structure.