Negative ion formation and evolution in atmospheric pressure corona discharges between point-to-plane electrodes with arbitrary needle angle

NASA Astrophysics Data System (ADS)

Sekimoto, K.; Takayama, M.

2010-12-01

The change in the distribution pattern of negative ions HO-, NOx- and COx- observed on arbitrary point-to-plane electrode configuration has been investigated by varying the angle of needle to the plane electrode, under atmospheric pressure corona discharge conditions. The stationary inhomogeneous electric field distributions between the point-to-plane electrodes with arbitrary needle angle were calculated. The experimental and theoretical results obtained suggested that the negative ion evolutions progress along field lines established between the electrodes with arbitrary configurations and the resulting terminal ion formation on a given field line is attributable to the electric field strength on the needle tip surface where the field line arose. The NOx- and COx- ions were dominantly produced on the field lines arising from the needle tip apex region with the highest electric field strength, while the field lines emanating from the tip peripheral regions with lower field strength resulted in the formation of the HO- ion.

The myth of the 90 degrees-angle intramuscular injection.

PubMed

Katsma, D L; Katsma, R

2000-01-01

This article shows that the textbook 90 degrees-angle requirement for intramuscular injections is unrealistic. Trigonometry demonstrates that an injection given at 72 degrees reaches 95% of the depth of an injection given at 90 degrees. This relation between needle angle and needle depth, previous research into the kinematics of hand motion during an intramuscular injection, and other practical considerations support the proposal for a new, relaxed standard: Intramuscular injections administered at a comfortable angle between 72 degrees and 90 degrees.

Paraesthesia during the needle-through-needle and the double segment technique for combined spinal epidural anaesthesia.

PubMed

Ahn, H J; Choi, D H; Kim, C S

2006-07-01

Paraesthesia during regional anaesthesia is an unpleasant sensation for patients and, more importantly, in some cases it is related to neurological injury. Relatively few studies have been conducted on the frequency of paraesthesia during combined spinal epidural anaesthesia. We compared two combined spinal epidural anaesthesia techniques: the needle-through-needle technique and the double segment technique in this respect. We randomly allocated 116 parturients undergoing elective Caesarean section to receive anaesthesia using one of these techniques. Both techniques were performed using a 27G pencil point needle, an 18G Tuohy needle, and a 20G multiport epidural catheter from the same manufacturer. The overall frequency of paraesthesia was higher in the needle-through-needle technique group (56.9% vs. 31.6%, p = 0.011). The frequency of paraesthesia at spinal needle insertion was 20.7% in the needle-through-needle technique group and 8.8% in the double segment technique group; whereas the frequency of paraesthesia at epidural catheter insertion was 46.6% in the needle-through-needle technique group and 24.6% in the double segment technique group.

Surface localization of sacral foramina for neuromodulation of bladder function. An anatomical study.

PubMed

Hasan, S T; Shanahan, D A; Pridie, A K; Neal, D E

1996-01-01

A method is described for percutaneous localization of the sacral foramina, for neuromodulation of bladder function. We carried out an anatomical study of 5 male and 5 female human cadaver pelves. Using the described surface markings, needles were placed percutaneously into all sacral foramina from nine different angles. Paths of needle entry were studied by subsequent dissection. We observed that although it was possible to enter any sacral foramen at a wide range of insertion angles, the incidence of nerve root/vascular penetration increased with increasing angle of needle entry. Also, the incidence of nerve root penetration was higher with the medial approach compared with lateral entry. The insertion of a needle into the S1 foramen was associated with a higher incidence of nerve root penetration and presents a potential for arterial haemorrhage. On the other hand the smaller S3 and S4 nerve roots were surrounded by venous plexuses, presenting a potential source of venous haemorrhage during procedures. Our study suggests a new method for identifying the surface markings of sacral foramina and it describes the paths of inserted needles into the respective foramina. In addition, it has highlighted some potential risk factors secondary to needle insertion.

Fresnel field interaction applied to scattering from a vegetation layer

NASA Technical Reports Server (NTRS)

Fung, A. K.; Chen, M. F.; Lee, K. K.

1987-01-01

Models for scattering from a vegetation layer treated as a collection of discrete scatterers usually assume far field interaction among scatterers. In a real vegetation medium such as a deciduous forest or a soybean field it is not always true that each leaf is in the far field of other leaves. This paper examines the additional effect when scatterers are permitted to be in the Fresnel zone of one another. Both disc-shaped and needle-shaped leaves are considered. It is found that in general this causes the backscattering coefficient to be lower for the disk-shaped leaves and may be higher or lower for the needle-shaped leaves depending upon polarization, incidence angle, and frequency than those computed under the assumption of conventional far field interaction.

Effect of vibration frequency on biopsy needle insertion force.

PubMed

Tan, Lei; Qin, Xuemei; Zhang, Qinhe; Zhang, Hongcai; Dong, Hongjian; Guo, Tuodang; Liu, Guowei

2017-05-01

Needle insertion is critical in many clinical medicine procedures, such as biopsy, brachytherapy, and injection therapy. A platform with two degrees of freedom was set up to study the effect of vibration frequency on needle insertion force. The gel phantom deformation at the needle cutting edge and the Voigt model are utilized to develop a dynamic model to explain the relationship between the insertion force and needle-tip velocity. The accuracy of this model was verified by performing needle insertions into phantom gel. The effect of vibration on insertion force can be explained as the vibration increasing the needle-tip velocity and subsequently increasing the insertion force. In a series of needle insertion experiments with different vibration frequencies, the peak forces were selected for comparison to explore the effect of vibration frequency on needle insertion force. The experimental results indicate that the insertion force at 500Hz increases up to 17.9% compared with the force at 50Hz. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Automatic detection of a hand-held needle in ultrasound via phased-based analysis of the tremor motion

NASA Astrophysics Data System (ADS)

Beigi, Parmida; Salcudean, Septimiu E.; Rohling, Robert; Ng, Gary C.

2016-03-01

This paper presents an automatic localization method for a standard hand-held needle in ultrasound based on temporal motion analysis of spatially decomposed data. Subtle displacement arising from tremor motion has a periodic pattern which is usually imperceptible in the intensity image but may convey information in the phase image. Our method aims to detect such periodic motion of a hand-held needle and distinguish it from intrinsic tissue motion, using a technique inspired by video magnification. Complex steerable pyramids allow specific design of the wavelets' orientations according to the insertion angle as well as the measurement of the local phase. We therefore use steerable pairs of even and odd Gabor wavelets to decompose the ultrasound B-mode sequence into various spatial frequency bands. Variations of the local phase measurements in the spatially decomposed input data is then temporally analyzed using a finite impulse response bandpass filter to detect regions with a tremor motion pattern. Results obtained from different pyramid levels are then combined and thresholded to generate the binary mask input for the Hough transform, which determines an estimate of the direction angle and discards some of the outliers. Polynomial fitting is used at the final stage to remove any remaining outliers and improve the trajectory detection. The detected needle is finally added back to the input sequence as an overlay of a cloud of points. We demonstrate the efficiency of our approach to detect the needle using subtle tremor motion in an agar phantom and in-vivo porcine cases where intrinsic motion is also present. The localization accuracy was calculated by comparing to expert manual segmentation, and presented in (mean, standard deviation and root-mean-square error) of (0.93°, 1.26° and 0.87°) and (1.53 mm, 1.02 mm and 1.82 mm) for the trajectory and the tip, respectively.

Planar super-oscillatory lens for sub-diffraction optical needles at violet wavelengths

PubMed Central

Yuan, Guanghui; Rogers, Edward T. F.; Roy, Tapashree; Adamo, Giorgio; Shen, Zexiang; Zheludev, Nikolay I.

2014-01-01

Planar optical lenses are fundamental elements of miniaturized photonic devices. However, conventional planar optical lenses are constrained by the diffraction limit in the optical far-field due to the band-limited wavevectors supported by free-space and loss of high-spatial-frequency evanescent components. As inspired by Einstein's radiation ‘needle stick', electromagnetic energy can be delivered into an arbitrarily small solid angle. Such sub-diffraction optical needles have been numerically investigated using diffractive optical elements (DOEs) together with specially polarized optical beams, but experimental demonstration is extremely difficult due to the bulky size of DOEs and the required alignment precision. Planar super-oscillatory lenses (SOLs) were proposed to overcome these constraints and demonstrated that sub-diffraction focal spots can actually be formed without any evanescent waves, making far-field, label-free super-resolution imaging possible. Here we extend the super-oscillation concept into the vectorial-field regime to work with circularly polarized light, and experimentally demonstrate, for the first time, a circularly polarized optical needle with sub-diffraction transverse spot size (0.45λ) and axial long depth of focus (DOF) of 15λ using a planar SOL at a violet wavelength of 405 nm. This sub-diffraction circularly polarized optical needle has potential applications in circular dichroism spectroscopy, super-resolution imaging, high-density optical storage, heat-assisted magnetic recording, nano-manufacturing and nano-metrology. PMID:25208611

[Doubting the twirling angle of filiform needle in Science of Acupuncture and Moxibustion textbooks and National Standards].

PubMed

Tian, Kaiyu

2016-07-12

In National Standards (GB) as well as the textbooks used in TCM universities, the twirling angles of acupuncture manipulation vary a lot. By reviewing the previous editions of textbooks from 3 publication houses and comparing the relevant contents, the author calculated the arc lengths of various twirling angles based on the specification of filiform needle in National Standards (GB) and International Standards (ISO). The conclusion is that the twirling angles mentioned in National Standards (GB) and textbooks are too small and not in compliance with the clinical practice. Hence, it is not advisable to propose a rigid specific provision of twirling angle in acupuncture manipulation.

Methods for Improving the Curvature of Steerable Needles in Biological Tissue

PubMed Central

Adebar, Troy K.; Greer, Joseph D.; Laeseke, Paul F.; Hwang, Gloria L.; Okamura, Allison M.

2016-01-01

Robotic needle steering systems have the potential to improve percutaneous interventions such as radiofrequency ablation of liver tumors, but steering techniques described to date have not achieved sufficiently small radius of curvature in biological tissue to be relevant to this application. In this work, the impact of tip geometry on steerable needle curvature is examined. Finite-element simulations and experiments with bent-tip needles in ex vivo liver tissue demonstrate that selection of tip length and angle can greatly improve curvature, with radius of curvature below 5 cm in liver tissue possible through judicious selection of these parameters. Motivated by the results of this analysis, a new articulated-tip steerable needle is described, in which a distal section is actively switched by a robotic system between a straight tip (resulting in a straight path) and a bent tip (resulting in a curved path). This approach allows the tip length and angle to be increased, while the straight configuration allows the needle tip to still pass through an introducer sheath and rotate inside the body. Validation testing in liver tissue shows that the new articulated-tip steerable needle achieves smaller radius of curvature compared to bent-tip needles described in previous work. Steerable needles with optimized tip parameters, which can generate tight curves in liver tissue, increase the clinical relevance of needle steering to percutaneous interventions. PMID:26441438

Needle twins and right-angled twins in minerals: comparison between experiment and theory

USGS Publications Warehouse

Salje, E.K.H.; Buckley, A.; Van Tendeloo, G.; Ishibashi, Y.; Nord, G.L.

1998-01-01

Transformation twinning in minerals forms isolated twin walls, intesecting walls with corner junctions, and wedge-shaped twins as elements of hierarchical patterns. When cut perpendicular to the twin walls, the twins have characteristic shapes, right-angled and needle-shaped wall traces, which can be observed by transmission electron microscopy or by optical microscopy. Theoretical geometries of wall shapes recently derived for strain-related systems should hold for most displacive and order-disorder type phase transitions: 1) right-angled twins show curved junctions; 2) needle-shaped twins contain flat wall segments near the needle tip if the elastic behaviour of the mineral is dominated by its anisotroyp; 3) additional bending forces and pinning effects lead to curved walls near the junction that make the needle tip appear more blunt. Bent right-angled twins were analyzed in Gd2(MoO4)3. Linear needle tips were found in WO3, [N(CH3)4]2.ZnBr4 CrAl, BiVO4, GdBa2Cu3O7, and PbZrO. Parabolic tips occur in K2Ba(NO2)4, and GeTe whereas exponential curvatures appear in BaTiO3, KSCN, Pb3(PO4)2, CaTiO3, alkali feldspars, YBa2Cu3O7, and MnAl. The size and shape of the twin microstructure relates to its formation during the phase transition and the subsequent annealing history. The mobility of the twin walls after formation depends not only on the thermal activation but also on the structure of the wall, which may be pinned to impurities on a favorable structural site. Depinnign energies are often large compared with thermal energies for diffusion. This leads to kinetic time scales for twin coarsening that are comparable to geological time scales. Therefore, transformation twins that exhibit needle domains not only indicate that the mineral underwent a structural phase transition but also contain information about its subsequent geological history.

Optimal angle of needle insertion for fluoroscopy-guided transforaminal epidural injection of L5.

PubMed

Ra, In-Hoo; Min, Woo-Kie

2015-06-01

Unlike other sites, there is difficulty in performing TFESI at the L5-S1 level because the iliac crest is an obstacle to needle placement. The objective of this study was to identify the optimal angle of fluoroscopy for insertion and advancement of a needle during L5 TEFSI. We conducted an observational study of patients undergoing fluoroscopy-guided L5 TFESI in the prone position. A total of 80 patients (40 men and 40 women) with radiating pain of lower limbs were enrolled. During TFESI, we measured the angle at which the L5 vertebral body forms a rectangular shape and compared men and women. Then, we measured area of safe triangle in tilting angle of fluoroscopy from 15° to 35° and compared men and women. The mean cephalocaudal angle, where the vertebral body takes the shape of a rectangle, was 11.0° in men and 13.9° in women (P = 0.007). In men, the triangular area was maximal at 18.3 mm² with an oblique view angle of 25°. In women, the area was maximal at 23.6 mm² with an oblique view angle of 30°. At an oblique view angle of 30° and 35°, the area was significantly greater in women (P < 0.05). When TFESI is performed at the L5 region in the prone position, placement of fluoroscopy at a cephalocaudal angle of 11.0° and an oblique angle of 25° in men and cephalocaudal angle of 13.9° and an oblique angle of 30° in women would be most reasonable. © 2014 World Institute of Pain.

Hyper- and viscoelastic modeling of needle and brain tissue interaction.

PubMed

Lehocky, Craig A; Yixing Shi; Riviere, Cameron N

2014-01-01

Deep needle insertion into brain is important for both diagnostic and therapeutic clinical interventions. We have developed an automated system for robotically steering flexible needles within the brain to improve targeting accuracy. In this work, we have developed a finite element needle-tissue interaction model that allows for the investigation of safe parameters for needle steering. The tissue model implemented contains both hyperelastic and viscoelastic properties to simulate the instantaneous and time-dependent responses of brain tissue. Several needle models were developed with varying parameters to study the effects of the parameters on tissue stress, strain and strain rate during needle insertion and rotation. The parameters varied include needle radius, bevel angle, bevel tip fillet radius, insertion speed, and rotation speed. The results will guide the design of safe needle tips and control systems for intracerebral needle steering.

Endpoint Accuracy in Manual Control of a Steerable Needle.

PubMed

van de Berg, Nick J; Dankelman, Jenny; van den Dobbelsteen, John J

2017-02-01

To study the ability of a human operator to manually correct for errors in the needle insertion path without partial withdrawal of the needle by means of an active, tip-articulated steerable needle. The needle is composed of a 1.32-mm outer-diameter cannula, with a flexure joint near the tip, and a retractable stylet. The bending stiffness of the needle resembles that of a 20-gauge hypodermic needle. The needle functionality was evaluated in manual insertions by steering to predefined targets and a lateral displacement of 20 mm from the straight insertion line. Steering tasks were conducted in 5 directions and 2 tissue simulants under image guidance from a camera. The repeatability in instrument actuations was assessed during 100 mm deep automated insertions with a linear motor. In addition to tip position, tip angles were tracked during the insertions. The targeting error (mean absolute error ± standard deviation) during manual steering to 5 different targets in stiff tissue was 0.5 mm ± 1.1. This variability in manual tip placement (1.1 mm) was less than the variability among automated insertions (1.4 mm) in the same tissue type. An increased tissue stiffness resulted in an increased lateral tip displacement. The tip angle was directly controlled by the user interface, and remained unaffected by the tissue stiffness. This study demonstrates the ability to manually steer needles to predefined target locations under image guidance. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

Development of Needle Insertion Manipulator for Central Venous Catheterization

NASA Astrophysics Data System (ADS)

Kobayashi, Yo; Hong, Jaesung; Hamano, Ryutaro; Hashizume, Makoto; Okada, Kaoru; Fujie, Masakatsu G.

Central venous catheterization is a procedure, which a doctor insert a catheter into the patient’s vein for transfusion. Since there are risks of bleeding from arterial puncture or pneumothorax from pleural puncture. Physicians are strictly required to make needle reach up into the vein and to stop the needle in the middle of vein. We proposed a robot system for assisting the venous puncture, which can relieve the difficulties in conventional procedure, and the risks of complication. This paper reports the design structuring and experimental results of needle insertion manipulator. First, we investigated the relationship between insertion force and angle into the vein. The results indicated that the judgment of perforation using the reaction force is possible in case where the needling angle is from 10 to 20 degree. The experiment to evaluate accuracy of the robot also revealed that it has beyond 0.5 mm accuracy. We also evaluated the positioning accuracy in the ultrasound images. The results displays that the accuracy is beyond 1.0 mm and it has enough for venous puncture. We also carried out the venous puncture experiment to the phantom and confirm our manipulator realized to make needle reach up into the vein.

Two-dimensional mapping of needle visibility with linear and curved array for ultrasound-guided interventional procedure

NASA Astrophysics Data System (ADS)

Susanti, Hesty; Suprijanto, Kurniadi, Deddy

2018-02-01

Needle visibility in ultrasound-guided technique has been a crucial factor for successful interventional procedure. It has been affected by several factors, i.e. puncture depth, insertion angle, needle size and material, and imaging technology. The influences of those factors made the needle not always well visible. 20 G needles of 15 cm length (Nano Line, facet) were inserted into water bath with variation of insertion angles and depths. Ultrasound measurements are performed with BK-Medical Flex Focus 800 using 12 MHz linear array and 5 MHz curved array in Ultrasound Guided Regional Anesthesia mode. We propose 3 criteria to evaluate needle visibility, i.e. maximum intensity, mean intensity, and the ratio between minimum and maximum intensity. Those criteria were then depicted into representative maps for practical purpose. The best criterion candidate for representing the needle visibility was criterion 1. Generally, the appearance pattern of the needle from this criterion was relatively consistent, i.e. for linear array, it was relatively poor visibility in the middle part of the shaft, while for curved array, it is relatively better visible toward the end of the shaft. With further investigations, for example with the use of tissue-mimicking phantom, the representative maps can be built for future practical purpose, i.e. as a tool for clinicians to ensure better needle placement in clinical application. It will help them to avoid the "dead" area where the needle is not well visible, so it can reduce the risks of vital structures traversing and the number of required insertion, resulting in less patient morbidity. Those simple criteria and representative maps can be utilized to evaluate general visibility patterns of the needle in vast range of needle types and sizes in different insertion media. This information is also important as an early investigation for future research of needle visibility improvement, i.e. the development of beamforming strategies and ultrasound enhanced (echogenic) needle.

Pinus sylvestris L. needle surface wettability parameters as indicators of atmospheric environment pollution impacts: Novel contact angle hysteresis methodology

NASA Astrophysics Data System (ADS)

Pogorzelski, Stanisław J.; Rochowski, Pawel; Szurkowski, Janusz

2014-02-01

An investigation of water contact angles (CAs), contact angle hysteresis (CAH) was carried out for 1-year to 4-year old needles (Pinus sylvestris) collected in urban (Gdansk) and rural (Karsin) locations using an original measuring technique based on the geometry of the drop on a vertical filament. Concentrations of air pollutants (SO2, NOx, C6H6, and suspended particular matter - SPM) currently considered to be most important in causing direct damage to vegetation were simultaneously monitored. A set of the surface wettability parameters: the apparent surface free energy γSV, adhesive film tension Π, work of adhesion WA, and spreading WS, were determined from CAH data using the approach developed by Chibowski (2003) to quantify the surface energetics of the needle substrata affected by aging and pollution impacts. This formalism relates the total apparent surface free energy of the solid γSV with only three measurable quantities: the surface tension of the probe liquid γLV and its advancing θA and receding θR contact angle hysteresis. Since CAH depends on the outermost wax layer surface roughness and spatial physicochemical heterogeneity of a solid surface, CA data were corrected using surface architecture profiles registered with confocal scanning laser microscopy. It was found that the roughness parameter r is significantly negatively correlated (R = -0.74) with the needle age (collected at Karsin). The needle surface aging process resulted in its surface hydrophilization (CA↓ and CAH↓ with γSV↑ and WA↑). A temporal evolution of the needles wettability was traced with the data point distribution in the 2D space of CAH plotted versus WS. The wettability parameters were closely correlated to pollutant concentrations as evidenced from Spearman's rank correlation procedure (R = 0.63-0.91; p < 0.05). The aim of the study was to validate the established CA methodology to create a new non-invasive, low-cost technique suitable for monitoring of structural changes at interfaces of biological systems.

Ultrasonography in Acupuncture-Uses in Education and Research.

PubMed

Leow, Mabel Qi He; Cui, Shu Li; Mohamed Shah, Mohammad Taufik Bin; Cao, Taige; Tay, Shian Chao; Tay, Peter Kay Chai; Ooi, Chin Chin

2017-06-01

This study aims to explore the potential use of ultrasound in locating the second posterior sacral foramen acupuncture point, quantifying depth of insertion and describing surrounding anatomical structures. We performed acupuncture needle insertion on a study team member. There were four steps in our experiment. First, the acupuncturist located the acupuncture point by palpation. Second, we used an ultrasound machine to visualize the structures surrounding the location of the acupuncture point and measure the depth required for needle insertion. Third, the acupuncturist inserted the acupuncture needle into the acupuncture point at an angle of 30°. Fourth, we performed another ultrasound scan to ensure that the needle was in the desired location. Results suggested that ultrasound could be used to locate the acupuncture point and estimate the depth of needle insertion. The needle was inserted to a depth of 4.0 cm to reach the surface of the sacral foramen. Based on Pythagoras theorem, taking a needle insertion angle of 30° and a needle insertion depth of 4.0 cm, the estimated perpendicular depth is 1.8 cm. An ultrasound scan corroborated the depth of 1.85 cm. The use of an ultrasound-guided technique for needle insertion in acupuncture practice could help standardize the treatment. Clinicians and students would be able to visualize and measure the depth of the sacral foramen acupuncture point, to guide the depth of needle insertion. This methodological guide could also be used to create a standard treatment protocol for research. A similar mathematical guide could also be created for other acupuncture points in future. Copyright © 2017. Published by Elsevier B.V.

PMN-PT single crystal, high-frequency ultrasonic needle transducers for pulsed-wave Doppler application.

PubMed

Zhou, Qifa; Xu, Xiaochen; Gottlieb, Emanuel J; Sun, Lei; Cannata, Jonathan M; Ameri, Hossein; Humayun, Mark S; Han, Pengdi; Shung, K Kirk

2007-03-01

High-frequency needle ultrasound transducers with an aperture size of 0.4 mm were fabricated using lead magnesium niobate-lead titanate (PMN-33% PT) as the active piezoelectric material. The active element was bonded to a conductive silver particle matching layer and a conductive epoxy backing through direct contact curing. An outer matching layer of parylene was formed by vapor deposition. The active element was housed within a polyimide tube and a 20-gauge needle housing. The magnitude and phase of the electrical impedance of the transducer were 47 omega and -38 degrees, respectively. The measured center frequency and -6 dB fractional bandwidth of the PMN-PT needle transducer were 44 MHz and 45%, respectively. The two-way insertion loss was approximately 15 dB. In vivo high-frequency, pulsed-wave Doppler patterns of blood flow in the posterior portion and in vitro ultrasonic backscatter microscope (UBM) images of the rabbit eye were obtained with the 44-MHz needle transducer.

Cutting performance orthogonal test of single plane puncture biopsy needle based on puncture force

NASA Astrophysics Data System (ADS)

Xu, Yingqiang; Zhang, Qinhe; Liu, Guowei

2017-04-01

Needle biopsy is a method to extract the cells from the patient's body with a needle for tissue pathological examination. Many factors affect the cutting process of soft tissue, including the geometry of the biopsy needle, the mechanical properties of the soft tissue, the parameters of the puncture process and the interaction between them. This paper conducted orthogonal experiment of main cutting parameters based on single plane puncture biopsy needle, and obtained the cutting force curve of single plane puncture biopsy needle by studying the influence of the inclination angle, diameter and velocity of the single plane puncture biopsy needle on the puncture force of the biopsy needle. Stage analysis of the cutting process of biopsy needle puncture was made to determine the main influencing factors of puncture force during the cutting process, which provides a certain theoretical support for the design of new type of puncture biopsy needle and the operation of puncture biopsy.

Elbow Angle during a Simulated Task Requiring Fine Psychomotor Control.

ERIC Educational Resources Information Center

Colangelo, Gary A.; And Others

1991-01-01

This study examined elbow angle during a fine motor task (threading a needle), in the context of positions used in preclinical training exercises and assumed by practitioners performing dental procedures. The 101 subjects tended to choose an obtuse angle (mean of 125 degrees) and to vary this angle only slightly in repeated trials. (DB)

Post dural puncture headache after spinal anaesthesia for caesarean section: a comparison of 25 g Quincke, 27 g Quincke and 27 g Whitacre spinal needles.

PubMed

Shaikh, Jan Muhammad; Memon, Amna; Memon, Muhammad Ali; Khan, Majida

2008-01-01

To compare the frequency and severity of post dural puncture headache in obstetric patients using 25G Quincke, 27G Quincke and 27G Whitacre spinal needles. Comparative, randomized, double-blind, interventional study. Liaquat University Hospital Hyderabad from October 2005 to December 2006. 480 ASA I-II full term pregnant women, 18 to 45 years of age, scheduled for elective Caesarean section, under spinal anaesthesia, were randomized into three groups: Group I (25G Quincke spinal needle: n=168), Group II (27G Quincke spinal needle: n=160) and Group III (27G Whitacre spinal needle: n=152). Spinal anaesthesia was performed with 1.5-2.0 ml 0.75% hyperbaric bupivacaine using 25G Quincke spinal needle (Group I), 27G Quincke spinal needle (Group II) and 27G Whitacre spinal needle (Group III) at L3-4 inter-vertebral space. Each patient was assessed daily for four consecutive days following Caesarean section. Frequency and severity and of postdural puncture headache (PDPH) were recorded. Data were analyzed using SPSS-11. Frequency of PDPH following the use of 25G Quincke (Group I), 27G Quincke (Group II) and 27G Whitacre (Group III) spinal needles was 8.3% (14/168), 3.8% (6/160) and 2.0% (3/152) respectively. In Group I, PDPH was mild in 5 patients, moderate in 7 patients and severe in 2 patients. In Group II, it was mild in 2, moderate in 3 and severe in 1 patient. In group III, it was mild in 2 and moderate in 1 patient. Severe PDPH did not occur in Group III. Most of the patients with PDPH developed it on 1st and 2nd postoperative day. When using a 27G Whitacre spinal needle, the frequency and severity of PDPH was significantly lower than when a 25G Quincke or 27G Quincke needle was used.

Lower incidence of postdural puncture headache using whitacre spinal needles after spinal anesthesia: A meta-analysis.

PubMed

Zhang, Di; Chen, LingXiao; Chen, XingYu; Wang, XiaoBo; Li, YuLin; Ning, GuangZhi; Feng, ShiQing

2016-03-01

The aim of this meta-analysis was to evaluate the postdural puncture headache after spinal anesthesia with Whitacre spinal needles compared with Quincke spine needles. We searched several databases, including PubMed, Embase, ISI Web of Knowledge, and Cochrane Central Register of Controlled Trials until October 10th, 2014, for randomized controlled trials that compared spinal anesthesia with Whitacre spinal needles or Quincke spine needles for postdural puncture headache. Two reviewers independently screened the literature, assessed the risk for bias and extracted data. We used RevMan 5.3 software to perform the meta-analysis. Studies were included for the main end points if they addressed the following: frequency of postdural puncture headache, severity of postdural puncture headache as assessed by limitation of activities, and frequency of epidural blood patch. Nine randomized controlled trials were included for meta-analysis. The meta-analysis showed that spinal anesthesia with Whitacre spinal needles achieved lower incidence of postdural puncture headache(RR 0.34; 95% CI [0.22, 0.52]; P < .00001); in addition, the severity of postdural puncture headache was lower in the Whitacre spinal needle group (RR 0.32; 95% CI [0.16, 0.66]; P = .002). Furthermore, the frequency of an epidural blood patch in the Whitacre spinal needle group was lower compared with that in the Quincke spine needle group (RR 0.15; 95% CI [0.04, 0.51]; P = .002). We suggest the Whitacre spinal needles as a superior choice for spinal anesthesia compared with Quincke spine needles. © 2016 American Headache Society.

Evaluation of 8.0-cm needle at the fourth anterior axillary line for needle chest decompression of tension pneumothorax.

PubMed

Chang, Samuel J; Ross, Samuel Wade; Kiefer, David J; Anderson, William E; Rogers, Amelia T; Sing, Ronald F; Callaway, David W

2014-04-01

Five-centimeter needles at the second intercostal space midclavicular line (2MCL) have high failure rates for decompression of tension pneumothorax. This study evaluates 8-cm needles directed at the fourth intercostal space anterior axillary line (4AAL). Retrospective radiographic analysis of 100 consecutive trauma patients 18 years or older from January to September 2011. Measurements of chest wall thickness (CWT) and depth to vital structure (DVS) were obtained at 2MCL and 4AAL. 4AAL measurements were taken based on two angles: closest vital structure and perpendicular to the chest wall. Primary outcome measures were radiographic decompression (RD) (defined as CWT < 80 mm) and radiographic noninjury (RNI) (DVS > 80 mm) of 8-cm needles at 4AAL. Secondary outcome measures are effect of angle of entry on RNI at 4AAL, RD and RNI of 8-cm needles at 2MCL, and comparison of 5-cm needles with 8-cm needles at both locations. Eighty-four percent of the patients were male, with mean Injury Severity Score (ISS) of 17.7 (range, 1.0-66.0) and body mass index of 26.8 (16.5-48.4). Mean CWT at 4AAL ranged from 37.6 mm to 39.9 mm, significantly thinner than mean CWT at 2MCL (43.3-46.7 mm). Eight-centimeter needle RD was more than 96% at both 4AAL and 2MCL. Five-centimeter RD ranged from 66% to 81% at all sites. Mean DVS at 4AAL ranged from 91.8 mm to 128.0 mm. RNI at all sites was more than 91% except at left 4AAL, when taken to the closest vital structure (mean DVS, 91.8 mm), with 68% RNI. Perpendicular entry increased DVS to 109.4 mm and subsequent RNI to 91%. Five-centimeter RNI at all sites was more than 99%. CWT at 4AAL is significantly thinner than 2MCL. Based on radiographic measurements, 8-cm catheters have a higher chance of pleural decompression when compared with 5-cm catheters. Steeper angle of entry at 4AAL improves 8-cm noninjury rates to more than 91%. Therapeutic/care management study, level IV.

Micro-fluid exchange coupling apparatus

NASA Technical Reports Server (NTRS)

Johnson, J. E., Jr.; Swartz, P. F. (Inventor)

1980-01-01

In a macro-fluid exchange, a hollow needle, such as a syringe needle, is provided for penetrating the fluid conduit of the animal. The syringe needle is coupled to a plenum chamber having an inlet and outlet port. The plenum chamber is coupled to the syringe needle via the intermediary of a standard quick disconnect coupling fitting. The plenum chamber is carried at the end of a drive rod which is coupled to a micrometer drive head. The micrometer drive head is slidably and pivotably coupled to a pedestal for adjusting the height and angle of inclination of the needle relative to a reference base support. The needle is positioned adjacent to the incised trachea or a blood vessel of a small animal and the micrometer drive head is operated for penetrating the fluid conduit of the animal.

Torsional Dynamics of Steerable Needles: Modeling and Fluoroscopic Guidance

PubMed Central

Swensen, John P.; Lin, MingDe; Okamura, Allison M.; Cowan, Noah J.

2017-01-01

Needle insertions underlie a diversity of medical interventions. Steerable needles provide a means by which to enhance existing needle-based interventions and facilitate new ones. Tip-steerable needles follow a curved path and can be steered by twisting the needle base during insertion, but this twisting excites torsional dynamics that introduce a discrepancy between the base and tip twist angles. Here, we model the torsional dynamics of a flexible rod—such as a tip-steerable needle—during subsurface insertion and develop a new controller based on the model. The torsional model incorporates time-varying mode shapes to capture the changing boundary conditions inherent during insertion. Numerical simulations and physical experiments using two distinct setups—stereo camera feedback in semi-transparent artificial tissue and feedback control with real-time X-ray imaging in optically opaque artificial tissue— demonstrate the need to account for torsional dynamics in control of the needle tip. PMID:24860026

Impact of the foliar pathogen Swiss needle cast on wood quality of Douglas-fir.

Treesearch

G.R. Johnson; Amy T. Grotta; Barbara L. Gartner; Geoff. Downes

2005-01-01

Many stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) near coastal areas of Oregon and Washington are heavily infected with the foliar pathogen causing Swiss needle cast (SNC) disease, and yet there is very little research on the resulting wood quality. Modulus of elasticity(MOE), modulus of rupture (MOR), microfibril angle (MFA), wood...

Modelling and characterisation of a ultrasound-actuated needle for improved visibility in ultrasound-guided regional anaesthesia and tissue biopsy.

PubMed

Kuang, Y; Hilgers, A; Sadiq, M; Cochran, S; Corner, G; Huang, Z

2016-07-01

Clear needle visualisation is recognised as an unmet need for ultrasound guided percutaneous needle procedures including regional anaesthesia and tissue biopsy. With inadequate needle visibility, these procedures may result in serious complications or a failed operation. This paper reports analysis of the modal behaviour of a previously proposed ultrasound-actuated needle configuration, which may overcome this problem by improving needle visibility in colour Doppler imaging. It uses a piezoelectric transducer to actuate longitudinal resonant modes in needles (outer diameter 0.8-1.2mm, length>65mm). The factors that affect the needle's vibration mode are identified, including the needle length, the transducer's resonance frequency and the gripping position. Their effects are investigated using finite element modelling, with the conclusions validated experimentally. The actuated needle was inserted into porcine tissue up to 30mm depth and its visibility was observed under colour Doppler imaging. The piezoelectric transducer is able to generate longitudinal vibration with peak-to-peak amplitude up to 4μm at the needle tip with an actuating voltage of 20Vpp. Actuated in longitudinal vibration modes (distal mode at 27.6kHz and transducer mode at 42.2kHz) with a drive amplitude of 12-14Vpp, a 120mm needle is delineated as a coloured line in colour Doppler images, with both needle tip and shaft visualised. The improved needle visibility is maintained while the needle is advanced into the tissue, thus allowing tracking of the needle position in real time. Moreover, the needle tip is highlighted by strong coloured artefacts around the actuated needle generated by its flexural vibration. A limitation of the technique is that the transducer mode requires needles of specific lengths so that the needle's resonance frequency matches the transducer. This may restrict the choice of needle lengths in clinical applications. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Needle tip visualization by bevel-point ultrasound generator and prototype photoacoustic imaging system

NASA Astrophysics Data System (ADS)

Irisawa, Kaku; Murakoshi, Dai; Hashimoto, Atsushi; Yamamoto, Katsuya; Hayakawa, Toshiro

2017-03-01

Visualization of the tip of medical devices like needles or catheters under ultrasound imaging has been a continuous topic since the early 1980's. In this study, a needle tip visualization system utilizing photoacoustic effects is proposed. In order to visualize the needle tip, an optical fiber was inserted into a needle. The optical fiber tip is placed on the needle bevel and affixed with black glue. The pulsed laser light from laser diode was transferred to the optical fiber and converted to ultrasound due to laser light absorption of the black glue and the subsequent photoacoustic effect. The ultrasound is detected by transducer array and reconstructed into photoacoustic images in the ultrasound unit. The photoacoustic image is displayed with a superposed ultrasound B-mode image. As a system evaluation, the needle is punctured into bovine meat and the needle tip is observed with commercialized conventional linear transducers or convex transducers. The needle tip is visualized clearly at 7 and 12 cm depths with linear and convex probes, respectively, even with a steep needle puncture angle of around 90 degrees. Laser and acoustic outputs, and thermal rise at the needle tip, were measured and were well below the limits of the safety standards. Compared with existing needle tip visualization technologies, the photoacoustic needle tip visualization system has potential distinguishable features for clinical procedures related with needle puncture and injection.

Simulation and fabrication of 0-3 composite PZT films for ultrahigh frequency (100-300 MHz) ultrasonic transducers

NASA Astrophysics Data System (ADS)

Chen, Xiaoyang; Fei, Chunlong; Chen, Zeyu; Chen, Ruimin; Yu, Ping; Chen, Zhongping; Shung, K. Kirk; Zhou, Qifa

2016-03-01

This paper presents simulation, fabrication, and characterization of single-element ultrahigh frequency (100-300-MHz) needle ultrasonic transducers based on 0-3 composite Pb(Zr0.52Ti0.48)O3 (PZT) films prepared by using composite ceramic sol-gel film and sol-infiltration technique. The center frequency of the developed transducer at 300-MHz was the highest frequency of PbTiO3 ceramic-based ultrasonic transducers ever reported. Furthermore, a brief description of the composite model was followed by the development of a new expression for predicting the longitudinal velocity, the clamped dielectric constant, and the complex electromechanical coupling coefficient kt of these films, which is very important in ultrasonic transducer design. Moreover, these parameters are difficult to obtain by measuring the frequency dependence of impedance and phase angle because of the weak signal of the previous 0-3 composite films transducer (>100 MHz). The modeling results show that the Cubes model with a geometric factor n = 0.05 fits well with the measured data. This model will be helpful for developing the 0-3 composite systems for ultrahigh frequency ultrasonic transducer design.

MANDIBULAR MORPHOMETRY APPLIED TO ANESTHETIC BLOCKAGE IN THE MANED WOLF (CHRYSOCYON BRACHYURUS).

PubMed

de Souza Junior, Paulo; de Moraes, Flavio Machado; de Carvalho, Natan da Cruz; Canelo, Evandro Alves; Thiesen, Roberto; Santos, André Luiz Quagliatto

2016-03-01

Chrysocyon brachyurus (maned wolf) is the biggest South American canid and has a high frequency of dental injuries, both in the wild and in captivity. Thus, veterinary procedures are necessary to preserve the feeding capacity of hundreds of captive specimens worldwide. The aim of this study was to investigate the mandibular morphometry of the maned wolf with emphasis on the establishment of anatomic references for anesthetic block of the inferior alveolar and mental nerves. Therefore, 16 measurements in 22 mandibles of C. brachyurus adults were taken. For extraoral block of the inferior alveolar nerve at the level of the mandibular foramen, the needle should be advanced close to the medial face of the mandibular ramus for 11.4 mm perpendicular to the palpable concavity. In another extraoral approach, the needle may be introduced for 30.4 mm from the angular process at a 20-25° angle to the ventral margin. For blocking only the mental nerve, the needle should be inserted for 10 mm from ventral border, close to the labial surface of the mandibular body, at the level of the lower first premolar. The mandibular foramen showed similar position, size, and symmetry in the maned wolf specimens examined. Comparison of the data observed here with those available for other carnivores indicates the need to determine these anatomic references specifically for each species.

Angle-Ply Weaving

NASA Technical Reports Server (NTRS)

Farley, Gary L.

1990-01-01

Bias-direction or angle-ply weaving is proposed new process for weaving fibers along bias in conventional planar fabric or in complicated three-dimensional multilayer fabric preform of fiber-reinforced composite structure. Based upon movement of racks of needles and corresponding angle yarns across fabric as fabric being formed. Fibers woven along bias increases shear stiffness and shear strength of preform, increasing value of preform as structural member.

Cadaveric and Ultrasonographic Validation of Needling Placement in the Cervical Multifidus Muscle.

PubMed

Fernández-de-Las-Peñas, César; Mesa-Jiménez, Juan A; Paredes-Mancilla, Jose A; Koppenhaver, Shane L; Fernández-Carnero, Samuel

2017-06-01

The aim of this study was to determine if a needle is able to reach the cervical multifidus during the application of dry needling or acupuncture. Dry needling and ultrasound imaging of cervical multifidi was conducted on 5 patients (age: 32 ± 5 years) with mechanical neck pain and on 2 fresh cadavers (age: 64 ± 1 years). Dry needling was done using a needle of 40 mm in length inserted perpendicular to the skin about 1 cm lateral to the spinous process at C3-C4. The needle was advanced from a posterior to anterior direction into the cervical multifidus with a slight inferior-medial angle (approximately 10°) to reach the vertebra lamina. For the cadaveric study, the multifidus was isolated by carefully resecting the superficial posterior cervical muscles: trapezius, splenius, and semispinalis. For the ultrasonographic study, a convex transducer was placed transversely over C3-C4 after the insertion of the needle into the muscle. The results of both the cadaveric and ultrasonic studies found that the needle does pierce the cervical multifidus muscle during insertion and that the tip of the needle rests properly against the vertebral laminae, thereby guarding the sensitive underlying spinal structures from damage. This anatomical and ultrasound imaging study supports that dry needling of the cervical multifidus could be conducted clinically. Copyright © 2017. Published by Elsevier Inc.

Velocity and size of droplets in dense region of diesel fuel spray on transient needle opening condition

NASA Astrophysics Data System (ADS)

Ueki, Hironobu; Ishida, Masahiro; Sakaguchi, Daisaku

2005-06-01

In order to investigate the effect of transient needle opening on early stage of spray behavior, simultaneous measurements of velocity and size of droplet were conducted by a newly developed laser 2-focus velocimeter (L2F). The micro-scale probe of the L2F was consisted of two foci with a distance of 36 µm. The tested nozzle had a single hole with a diameter of 0.2 mm. The measurements of injection pressure, needle lift, and crank angle were synchronized with the spray measurement by the L2F at the position 10 mm downstream from the nozzle exit. It has been clearly shown that the velocity and size of droplet increase with needle valve opening and that the probability density distribution of droplet size can be fitted to the Nukiyama-Tanasawa distribution under the transient needle opening condition.

Bleb needling outcomes for failed trabeculectomy blebs in Asian eyes: a 2-year follow up.

PubMed

Tsai, Andrew S H; Boey, Pui Yi; Htoon, Hla M; Wong, Tina T

2015-01-01

To describe the outcomes of bleb needling in primary glaucoma in an Asian tertiary eye centre over a 2y period. To compare the success rates between primary angle-closure glaucoma (PACG) and primary open angle glaucoma (POAG). Lastly, to identify factors associated with success of bleb needling. This was a retrospective review of 227 patients who underwent bleb needling between June 2009 and June 2011 in Singapore National Eye Centre. The 5-fluorouracil (5-FU) augmented bleb needling was performed either at the slit lamp or in the operating theatre. Repeat bleb needlings were performed as necessary. Complete success was defined as maintenance of intraocular pressure (IOP) ≥6 mm Hg and ≤21 mm Hg, in the absence of further surgery or use of antiglaucoma medication. Qualified success met the above criteria with or without use of antiglaucoma medications. One hundred and seventy-five eyes completed the two-year follow up. Sixty-nine percent of participants had POAG and 31% had PACG. The mean interval between filtering surgery and bleb needling was 299.9±616.4d for POAG and 167.1±272.2d for PACG. Mean needling attempts were 1.9±1.4 and 2±1.6 for POAG and PACG respectively. In general, there was a statistically significant reduction of IOP ranging from 21.9% to 26.8% from month 1 through to month 24. The complete success rates at month 6 were 70.0% for POAG and 65.7% for PACG. At month 12, this decreased to 62.2% for POAG and PACG and at month 24, 57.9% for POAG and 63.0% for PACG respectively. The qualified success rates at month 6 for POAG and PACG were 23.8% and 29.9% respectively, 32.2% and 29.2% at month 12, and 34.7% and 29.6% at month 24. The success rates between POAG and PACG were not significantly different (P>0.05 for complete and qualified success at months 6, 12 and 24). An increased number of needlings and higher pre-needling IOP were associated with failure. The 5-FU augmented bleb needling within one year of trabeculectomy in Asian eyes can provide clinically significant IOP lowering of more than 20% for 2y. POAG and PACG had similar complete success rates (58% and 63% respectively). Factors associated with greater risk of procedure failure included increased number of needlings and higher pre-needling IOP. Asian eyes have a greater propensity for scarring but bleb needling, if performed in a timely manner can rescue bleb function.

Bleb needling outcomes for failed trabeculectomy blebs in Asian eyes: a 2-year follow up

PubMed Central

Tsai, Andrew S. H.; Boey, Pui Yi; Htoon, Hla M; Wong, Tina T

2015-01-01

AIM To describe the outcomes of bleb needling in primary glaucoma in an Asian tertiary eye centre over a 2y period. To compare the success rates between primary angle-closure glaucoma (PACG) and primary open angle glaucoma (POAG). Lastly, to identify factors associated with success of bleb needling. METHODS This was a retrospective review of 227 patients who underwent bleb needling between June 2009 and June 2011 in Singapore National Eye Centre. The 5-fluorouracil (5-FU) augmented bleb needling was performed either at the slit lamp or in the operating theatre. Repeat bleb needlings were performed as necessary. Complete success was defined as maintenance of intraocular pressure (IOP) ≥6 mm Hg and ≤21 mm Hg, in the absence of further surgery or use of antiglaucoma medication. Qualified success met the above criteria with or without use of antiglaucoma medications. RESULTS One hundred and seventy-five eyes completed the two-year follow up. Sixty-nine percent of participants had POAG and 31% had PACG. The mean interval between filtering surgery and bleb needling was 299.9±616.4d for POAG and 167.1±272.2d for PACG. Mean needling attempts were 1.9±1.4 and 2±1.6 for POAG and PACG respectively. In general, there was a statistically significant reduction of IOP ranging from 21.9% to 26.8% from month 1 through to month 24. The complete success rates at month 6 were 70.0% for POAG and 65.7% for PACG. At month 12, this decreased to 62.2% for POAG and PACG and at month 24, 57.9% for POAG and 63.0% for PACG respectively. The qualified success rates at month 6 for POAG and PACG were 23.8% and 29.9% respectively, 32.2% and 29.2% at month 12, and 34.7% and 29.6% at month 24. The success rates between POAG and PACG were not significantly different (P>0.05 for complete and qualified success at months 6, 12 and 24). An increased number of needlings and higher pre-needling IOP were associated with failure. CONCLUSION The 5-FU augmented bleb needling within one year of trabeculectomy in Asian eyes can provide clinically significant IOP lowering of more than 20% for 2y. POAG and PACG had similar complete success rates (58% and 63% respectively). Factors associated with greater risk of procedure failure included increased number of needlings and higher pre-needling IOP. Asian eyes have a greater propensity for scarring but bleb needling, if performed in a timely manner can rescue bleb function. PMID:26309874

Arched needle technique for inferior alveolar mandibular nerve block.

PubMed

Chakranarayan, Ashish; Mukherjee, B

2013-03-01

One of the most commonly used local anesthetic techniques in dentistry is the Fischer's technique for the inferior alveolar nerve block. Incidentally this technique also suffers the maximum failure rate of approximately 35-45%. We studied a method of inferior alveolar nerve block by injecting a local anesthetic solution into the pterygomandibular space by arching and changing the approach angle of the conventional technique and estimated its efficacy. The needle after the initial insertion is arched and inserted in a manner that it approaches the medial surface of the ramus at an angle almost perpendicular to it. The technique was applied to 100 patients for mandibular molar extraction and the anesthetic effects were assessed. A success rate of 98% was obtained.

Semicircular thermocouple needle depth gauge for cryoprocedures.

PubMed

Pappenfort, R B

1981-06-01

A semicircular thermocouple needle depth gauge made of an aluminum alloy drilled with tracks at different angles to place thermocouple needles at various depths below the surface is described herein. Its shape offers definite advantages over circular jigs (templates) when doing cryoexperimentation and when used clinically. The material of which it is made is more durable than plastic. Grommets that firmly snap in place within the inner rim of the instrument permit accurate placement of liquid gas spray, cryoprobes, and other applicators directly over the thermocouple needle tips. This is of special importance when doing cryoexperiments. Furthermore, with this design, the advancing ice front and possible liquid gas runoff are more easily seen. By using both halves it is suitable for monitoring the temperature when freezing large tumors at two different sites and a different depths.

[Data Mining-revealed Characteristics of Clinical Application of Scalp Acupuncture].

PubMed

Wang, Qiong; Xing, Hai-Jiao; Bao, Na; Kong, Ling-Juan; Jia, Ye-Juan; Yang, Ke; Sun, Yan-Hui; Wang, Jian-Ling; Shi, Jing; Li, Xiao-Feng; Xu, Jing; Zhang, Xuan-Ping; Zhang, Xin; Jia, Chun-Sheng; Li, Ren-Ling

2018-03-25

To explore the regularity and characteristics of clinical application of scalp acupuncture therapy for different types of clinical conditions so as to provide a reference for clinical practice. In the present study, "head acupuncture" and"scalp acupuncture" were used as the keywords to search papers and academic dissertations having definite standards for diagnosis and therapeutic effect assessment and published in journals and academic conferences collected in database China National Knowledge Internet(CNKI) from January 1 of 1959 to December 31 of 2016, followed by constructing a database after sorting, screening, recording, extracting, and statistical analysis by using a computer. Then, the data mining was conducted for summarizing the indications of disease categories, involved medical departments, needle-insertion methods, needle manipulation techniques, academic schools, and clinical efficacy of scalp acupuncture therapy. As a result, a total of 587 papers met our including criteria were analyzed. The scalp acupuncture therapy was widely employed in the treatment of various clinical conditions of different departments, with the application frequency being the internal medicine (438 times), surgery (75 times), pediatrics (44 times), etc. Of the indicated 102 types of clinical problems, 55 belong to the internal medicine, constituting of 53.92%, particularly the cerebral apoplexy and its sequelae with the top application frequency being 102 and 115 times, respectively. In terms of needle inserting methods mentioned in partial papers (most papers do not mention), fingernail-pressing-aided needle insertion, needle-twirling insertion, fingers-squeezed-needle insertion, particularly the swiftly rotating needle insertion and rapid needle-propelling insertion were most commonly used.Regarding the needle manipulation method, rapid needle twirling technique was frequently employed, usually at a frequency of approximately 200 times per min. In regard to the academic schools, JIAO Shun-fa's scalp acupuncture system was most frequently used, followed by the international standardized scalp acupuncture. The therapeutic effect of scalp acupuncture is effective in the treatment of different conditions of various departments, especially those of the dermatology and gynecology. Scalp acupuncture has superiority in the treatment disorders of the internal medicine and has been demonstrated to have positive effects for many types of problems, particularly for apoplexy and its sequelae. Rapid needle-propelling insertion and rapid needle-twirling technique are often employed.

Grading of severity of postdural puncture headache after 27-gauge Quincke and Whitacre needles.

PubMed

Corbey, M P; Bach, A B; Lech, K; Frørup, A M

1997-06-01

Small-gauge needles are reported to have a low incidence of complications. Pencil-point needles are associated with a lower frequency of postdural puncture headache (PDPH), but a higher failure rate than Quincke needles. The incidence of PDPH was investigated in 200 patients under the age of 45, undergoing day-care surgery, after spinal anaesthesia with either 27-gauge Quincke or Whitacre needle. The severity of headache was graded as I (mild), II (moderate) or III (severe) using a grading system based on the visual analogue scale (VAS) associated with a functional rating (FG). The frequency of PDPH following the Whitacre needle was 0% and 5.6% after the Quincke needle (P = 0.05). Two PDPHs were assessed as grade III, and three as grade II. All PDPHs occurred when the Quincke needle bevel was withdrawn perpendicular to the dural fibres following parallel insertion. No PDPH occurred when the bevel was inserted and removed parallel to the dural fibres (P < 0.05). There was no statistical difference (P > 0.08) in the incidence of PDPH and postdural puncture-related headaches (PDPR-H) in patients with recurrent headaches or migraine compared to patients with no previous history of headaches. We conclude that the 27-gauge Whitacre needle is the 'needle of choice' in patients with normal body stature. The incidence of PDPH following Quincke needles may not only be affected by the direction of the bevel during insertion but also during removal. Statistically, there was no gender variation in PDPH in this study (P = 0.5). A previous history of recurrent headache or migraine does not predispose to PDPH.

Evidence for the use of dry needling and physiotherapy in the management of cervicogenic or tension-type headache: a systematic review.

PubMed

France, Stacey; Bown, Jenna; Nowosilskyj, Matthew; Mott, Megan; Rand, Stephanie; Walters, Julie

2014-10-01

There is good evidence in the literature supporting physiotherapy in the management of some forms of headache. Dry needling of myofascial trigger points is becoming an increasingly common approach despite a paucity of research evidence supporting its use. The purpose of this review was to determine the evidence supporting the use of dry needling in addition to conventional physiotherapy in the management of tension-type and cervicogenic headache. Ten databases were searched for evidence of the effect of dry needling on the severity and frequency of tension and cervicogenic headache based ICHD classifications. Three relevant studies were identified and all three showed statistically significant improvements following dry needling, but no significant differences between groups. Only one study reported on headache frequency or intensity, reporting a 45 mm improvement in VAS score following the addition of dry needling to conventional physiotherapy. Two studies showed significant improvements with dry needling over 4-5 weeks of treatment. No adverse events were reported. The literature suggests that while there is insufficient evidence to strongly advocate for the use of dry needling, it may be a useful addition to conventional physiotherapy in headache management. Further research with a stronger methodological design is required. © International Headache Society 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Comparison of cutting and pencil-point spinal needle in spinal anesthesia regarding postdural puncture headache

PubMed Central

Xu, Hong; Liu, Yang; Song, WenYe; Kan, ShunLi; Liu, FeiFei; Zhang, Di; Ning, GuangZhi; Feng, ShiQing

2017-01-01

Abstract Background: Postdural puncture headache (PDPH), mainly resulting from the loss of cerebral spinal fluid (CSF), is a well-known iatrogenic complication of spinal anesthesia and diagnostic lumbar puncture. Spinal needles have been modified to minimize complications. Modifiable risk factors of PDPH mainly included needle size and needle shape. However, whether the incidence of PDPH is significantly different between cutting-point and pencil-point needles was controversial. Then we did a meta-analysis to assess the incidence of PDPH of cutting spinal needle and pencil-point spinal needle. Methods: We included all randomly designed trials, assessing the clinical outcomes in patients given elective spinal anesthesia or diagnostic lumbar puncture with either cutting or pencil-point spinal needle as eligible studies. All selected studies and the risk of bias of them were assessed by 2 investigators. Clinical outcomes including success rates, frequency of PDPH, reported severe PDPH, and the use of epidural blood patch (EBP) were recorded as primary results. Results were evaluated using risk ratio (RR) with 95% confidence interval (CI) for dichotomous variables. Rev Man software (version 5.3) was used to analyze all appropriate data. Results: Twenty-five randomized controlled trials (RCTs) were included in our study. The analysis result revealed that pencil-point spinal needle would result in lower rate of PDPH (RR 2.50; 95% CI [1.96, 3.19]; P < 0.00001) and severe PDPH (RR 3.27; 95% CI [2.15, 4.96]; P < 0.00001). Furthermore, EBP was less used in pencil-point spine needle group (RR 3.69; 95% CI [1.96, 6.95]; P < 0.0001). Conclusions: Current evidences suggest that pencil-point spinal needle was significantly superior compared with cutting spinal needle regarding the frequency of PDPH, PDPH severity, and the use of EBP. In view of this, we recommend the use of pencil-point spinal needle in spinal anesthesia and lumbar puncture. PMID:28383416

[Postspinal headache. A comparison of the 24G Sprotte syringe and a 29G Quincke needle].

PubMed

Lim, M; Cross, G D; Sold, M

1992-09-01

A randomised study was performed to compare the frequency of postdural puncture headache in 56 patients who underwent spinal anaesthesia for extra-corporeal shockwave lithotripsy using either a Sprotte 24 G (n = 28) or Vygon 29 G or Quincke type needle (n = 28). Frequency of headache was recorded in a similar group of 28 patients who received general anaesthesia. Dural puncture was easier with the Sprotte 24 G cannula than with the less stable Quincke needle, as documented by a significantly shortened time for insertion of the cannula (4.6 +/- 2.6 vs 8.6 +/- 6.3 min, P less than 0.005). The total frequency of post-operative headache was 57% in the Vygon 29 G group and 25% in the Sprotte 24 G group; 21% of patients in the general anaesthesia group complained of headache. Frequency of postdural puncture headache, classified as being posture-related, was 25% in the 29 G Vygon group, compared with 11% in the 24 G Sprotte group (P = 0.148). When only moderate and severe postdural puncture headache was considered, there was a significant difference (25% vs. 4%; P = 0.026) in favour of the Sprotte cannula. Thus, the 24 G Sprotte needle was at least as effective as the 29 G Vygon needle, and there is a suggestion that the former is more effective in minimising the incidence of moderate or severe postdural puncture headache.

Simulation and experimental studies in needle-tissue interactions.

PubMed

Konh, Bardia; Honarvar, Mohammad; Darvish, Kurosh; Hutapea, Parsaoran

2017-08-01

This work aims to introduce a new needle insertion simulation to predict the deflection of a bevel-tip needle inside soft tissue. The development of such a model, which predicts the steering behavior of the needle during needle-tissue interactions, could improve the performance of many percutaneous needle-based procedures such as brachytherapy and thermal ablation, by means of the virtual path planning and training systems of the needle toward the target and thus reducing possible incidents of complications in clinical practices. The Arbitrary-Lagrangian-Eulerian (ALE) formulation in LS-DYNA software was used to model the solid-fluid interactions between the needle and tissue. Since both large deformation and fracture of the continuum need to be considered in this model, applying ALE method for fluid analysis was considered a suitable approach. A 150 mm long needle was used to bend within the tissue due to the interacting forces on its asymmetric bevel tip. Three experimental cases of needle steering in a soft phantom were performed to validate the simulation. An error measurement of less than 10 % was found between the predicted deflection by the simulations and the one observed in experiments, validating our approach with reasonable accuracy. The effect of the needle diameter and its bevel tip angle on the final shape of the needle was investigated using this model. To maneuver around the anatomical obstacles of the human body and reach the target location, thin sharp needles are recommended, as they would create a smaller radius of curvature. The insertion model presented in this work is intended to be used as a base structure for path planning and training purposes for future studies.

Benchmarking of state-of-the-art needle detection algorithms in 3D ultrasound data volumes

NASA Astrophysics Data System (ADS)

Pourtaherian, Arash; Zinger, Svitlana; de With, Peter H. N.; Korsten, Hendrikus H. M.; Mihajlovic, Nenad

2015-03-01

Ultrasound-guided needle interventions are widely practiced in medical diagnostics and therapy, i.e. for biopsy guidance, regional anesthesia or for brachytherapy. Needle guidance using 2D ultrasound can be very challenging due to the poor needle visibility and the limited field of view. Since 3D ultrasound transducers are becoming more widely used, needle guidance can be improved and simplified with appropriate computer-aided analyses. In this paper, we compare two state-of-the-art 3D needle detection techniques: a technique based on line filtering from literature and a system employing Gabor transformation. Both algorithms utilize supervised classification to pre-select candidate needle voxels in the volume and then fit a model of the needle on the selected voxels. The major differences between the two approaches are in extracting the feature vectors for classification and selecting the criterion for fitting. We evaluate the performance of the two techniques using manually-annotated ground truth in several ex-vivo situations of different complexities, containing three different needle types with various insertion angles. This extensive evaluation provides better understanding on the limitations and advantages of each technique under different acquisition conditions, which is leading to the development of improved techniques for more reliable and accurate localization. Benchmarking results that the Gabor features are better capable of distinguishing the needle voxels in all datasets. Moreover, it is shown that the complete processing chain of the Gabor-based method outperforms the line filtering in accuracy and stability of the detection results.

Treating primary dysmenorrhoea with acupuncture: a narrative review of the relationship between acupuncture 'dose' and menstrual pain outcomes.

PubMed

Armour, Mike; Smith, Caroline A

2016-12-01

A number of randomised controlled trials have been performed to determine the effectiveness or efficacy of acupuncture in primary dysmenorrhoea. The objective of this review was to explore the relationship between the 'dose' of the acupuncture intervention and menstrual pain outcomes. Eight databases were systematically searched for trials examining penetrating body acupuncture for primary dysmenorrhoea published in English up to September 2015. Dose components for each trial were extracted, assessed by the two authors and categorised by neurophysiological dose (number of needles, retention time and mode of stimulation), cumulative dose (total number and frequency of treatments), needle location and treatment timing. Eleven trials were included. Components of acupuncture dose were well reported across all trials. The relationship between needle location and menstrual pain demonstrated conflicting results. Treatment before the menses appeared to produce greater reductions in pain than treatment starting at the onset of menses. A single needle during menses may provide greater pain reduction compared to multiple needles. Conversely, multiple needles before menses were superior to a single needle. Electroacupuncture may provide more rapid pain reduction compared to manual acupuncture but may not have a significantly different effect on overall menstrual pain. There appear to be relationships between treatment timing and mode of needle stimulation, and menstrual pain outcomes. Needle location, number of needles used and frequency of treatment show clear dose-response relationships with menstrual pain outcomes. Current research is insufficient to make definitive clinical recommendations regarding optimum dose parameters for treating primary dysmenorrhoea. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Targeting of sebaceous glands to treat acne by micro-insulated needles with radio frequency in a rabbit ear model.

PubMed

Kwon, Tae-Rin; Choi, Eun Ja; Oh, Chang Taek; Bak, Dong-Ho; Im, Song-I; Ko, Eun Jung; Hong, Hyuck Ki; Choi, Yeon Shik; Seok, Joon; Choi, Sun Young; Ahn, Gun Young; Kim, Beom Joon

2017-04-01

Many studies have investigated the application of micro-insulated needles with radio frequency (RF) to treat acne in humans; however, the use of a micro-insulated needle RF applicator has not yet been studied in an animal model. The purpose of this study was to evaluate the effectiveness of a micro-insulated needle RF applicator in a rabbit ear acne (REA) model. In this study, we investigated the effect of selectively destroying the sebaceous glands using a micro-insulated needle RF applicator on the formation of comedones induced by application of 50% oleic acid and intradermal injection of P. acnes in the orifices of the external auditory canals of rabbits. The effects of the micro-insulated needle RF applicator treatment were evaluated using regular digital photography in addition to 3D Primos imaging evaluation, Skin Visio Meter microscopic photography, and histologic analyses. Use of the micro-insulated needle RF applicator resulted in successful selective destruction of the sebaceous glands and attenuated TNF-alpha release in an REA model. The mechanisms by which micro-insulated needles with RF using 1 MHz exerts its effects may involve inhibition of comedone formation, triggering of the wound healing process, and destruction of the sebaceous glands and papules. The use of micro-insulated needles with RF applicators provides a safe and effective method for improving the appearance of symptoms in an REA model. The current in vivo study confirms that the micro-insulated needle RF applicator is selectively destroying the sebaceous glands. Lasers Surg. Med. 49:395-401, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

[Discussion on several contents of textbook Acupuncture and Moxibustion (New Century 4th Edition)].

PubMed

Tian, Kaiyu

2018-02-12

The textbook Acupuncture and Moxibustion (New Century 4th Edition) was published by China Press of Traditional Chinese Medicine in August of 2016. The author proposed several discussions in the textbook. The information, including the issue date of China national standard Standardized Manipulations of Acupuncture and Moxibustion , the number of foreign countries where China medical teams were assigned, and the number of acupuncture indications recommended by WHO, was not accurate. The content, including several methods of acupoint location, specification of filiform needles, rotating angle of needle, disinfection of needles and skin, locations and indications of scalp acupuncture, etc. should be corrected. Besides, the writing of textbooks should follow national or industry standards.

[Special penetration needling for refractory peripheral facial paralysis].

PubMed

Cao, Rongjuan; Qiu, Xiaohu; Xie, Xiaokun

2018-03-12

To observe the clinical effect difference between special penetration needling and conventional penetration needling for the refractory peripheral facial paralysis. A total of 97 patients with intractable facial paralysis were randomized into an observation group (49 cases and 2 dropping) and a control group (48 cases and 4 dropping). In the observation group, special penetration needling at an angle about 45° between the penetration needle and paralysis muscle bundle was used, Yangbai (GB 14) through Touwei (ST 8), Yangbai (GB 14) through Shangxing (GV 23), Sizhukong (TE 23) through Yuyao (EX-HN 4), Qianzhen (Extra) through Yingxiang (LI 20), mutual penetration between Yingxiang (LI 20) and Jiache (ST 6). Conventional penetration needling was applied in the control group, Yangbai (GB 14) through Yuyao (EX-HN 4), Cuanzhu (BL 2) through Yuyao (EX-HN 4), mutual penetration between Dicang (ST 4) and Jiache (ST 6), Qianzheng (Extra) through Dicang (ST 4), Sibai (ST 2) through Yingxiang (LI 20). Three groups of electroacupuncture (discontinuous wave, 1 Hz) with tolerance were connected respectively in the two groups, Yangbai (GB 14) and Sizhukong (TE 23), Yangbai (GB 14) and Qianzheng (Extra), Yingxiang (LI 20) and Jiache (ST 6) in the observation group, Yangbai (GB 14) and Cuanzhu (BL 2), Dicang (ST 4) and Jiache (ST 6), Qianzheng (Extra) and Sibai (ST 2) in the control group. TDP was applied in the two groups at the affected Yifeng (TE 17), Jiache (ST 6) and Qianzheng (Extra), which were around the ear. Perpendicular insertion was used at Yifeng (TE 17) at the affected side and Hegu (LI 4) at the healthy side and bilateral Zusanli (ST 36). The needles were retained for 30 min. The treatment was given for 3 courses, once a day and 10 days as a course, 5 days at the interval. House-Brackmann (H-B) facial nerve grading score was recorded before and after treatment. The clinical effects were compared. The H-B scores after treatment in the two groups were higher than those before treatment (both P <0.05), with better result in the observation group ( P <0.05). The cured and markedly effective rate of the observation group was 74.5% (35/47), which was better than 47.7% (21/44) of the control group ( P <0.01). Special penetration needling at an angle about 45° between the penetration needle and paralysis muscle bundle is better than conventional penetration needling for refractory facial paralysis.

Canopy storage capacity and wettability of leaves and needles: The effect of water temperature changes

NASA Astrophysics Data System (ADS)

Klamerus-Iwan, Anna; Błońska, Ewa

2018-04-01

The canopy storage capacity (S) is a major component of the surface water balance. We analysed the relationship between the tree canopy water storage capacity and leaf wettability under changing simulated rainfall temperature. We estimated the effect of the rain temperature change on the canopy storage capacity and contact angle of leave and needle surfaces based on two scenarios. Six dominant forest trees were analysed: English oak (Quercus roburL.), common beech (Fagus sylvatica L.), small-leaved lime (Tilia cordata Mill), silver fir (Abies alba), Scots pine (Pinus sylvestris L.),and Norway spruce (Picea abies L.). Twigs of these species were collected from Krynica Zdrój, that is, the Experimental Forestry unit of the University of Agriculture in Cracow (southern Poland). Experimental analyses (simulations of precipitation) were performed in a laboratory under controlled conditions. The canopy storage capacity and leaf wettability classification were determined at 12 water temperatures and a practical calculator to compute changes of S and contact angles of droplets was developed. Among all species, an increase of the rainfall temperature by 0.7 °C decreases the contact angle between leave and needle surfaces by 2.41° and increases the canopy storage capacity by 0.74 g g-1; an increase of the rain temperature by 2.7 °C decreases the contact angle by 9.29° and increases the canopy storage capacity by 2.85 g g-1. A decreased contact angle between a water droplet and leaf surface indicates increased wettability. Thus, our results show that an increased temperature increases the leaf wettability in all examined species. The comparison of different species implies that the water temperature has the strongest effect on spruce and the weakest effect on oak. These data indicate that the rainfall temperature influences the canopy storage capacity.

String flash-boiling in gasoline direct injection simulations with transient needle motion

DOE PAGES

Baldwin, Eli T.; Grover, Jr., Ronald O.; Parrish, Scott E.; ...

2016-09-06

A computational study was performed to investigate the influence of transient needle motion on gasoline direct injection (GDI) internal nozzle flow and near-field sprays. Simulations were conducted with a compressible Eulerian flow solver modeling liquid, vapor, and non-condensable gas phases with a diffuse interface. Variable rate generation and condensation of fuel vapor were captured using the homogeneous relaxation model (HRM). The non-flashing (spray G) and flashing (spray G2) conditions specified by the Engine Combustion Network were modeled using the nominal spray G nozzle geometry and transient needle lift and wobble were based upon ensemble averaged x-ray imaging preformed at Argonnemore » National Lab. The minimum needle lift simulated was 5 μm and dynamic mesh motion was achieved with Laplacian smoothing. The results were qualitatively validated against experimental imaging and the experimental rate of injection profile was captured accurately using pressure boundary conditions and needle motion to actu- ate the injection. Needle wobble was found to have no measurable effect on the flow. Low needle lift is shown to result in vapor generation as fuel rushes past the needle. In conclusion, the internal injector flow is shown to contain many transient and interacting vortices which cause perturbations in the spray angle, fluctuations in the mass flux, and frequently result in string flash-boiling.« less

String flash-boiling in gasoline direct injection simulations with transient needle motion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldwin, Eli T.; Grover, Jr., Ronald O.; Parrish, Scott E.

A computational study was performed to investigate the influence of transient needle motion on gasoline direct injection (GDI) internal nozzle flow and near-field sprays. Simulations were conducted with a compressible Eulerian flow solver modeling liquid, vapor, and non-condensable gas phases with a diffuse interface. Variable rate generation and condensation of fuel vapor were captured using the homogeneous relaxation model (HRM). The non-flashing (spray G) and flashing (spray G2) conditions specified by the Engine Combustion Network were modeled using the nominal spray G nozzle geometry and transient needle lift and wobble were based upon ensemble averaged x-ray imaging preformed at Argonnemore » National Lab. The minimum needle lift simulated was 5 μm and dynamic mesh motion was achieved with Laplacian smoothing. The results were qualitatively validated against experimental imaging and the experimental rate of injection profile was captured accurately using pressure boundary conditions and needle motion to actu- ate the injection. Needle wobble was found to have no measurable effect on the flow. Low needle lift is shown to result in vapor generation as fuel rushes past the needle. In conclusion, the internal injector flow is shown to contain many transient and interacting vortices which cause perturbations in the spray angle, fluctuations in the mass flux, and frequently result in string flash-boiling.« less

[Efficacy observation of nonspecific low back pain treated with the dragon-tiger fighting needling method].

PubMed

Zhao, Feng; Cao, Dong-bo; Yuan, Yi-qin; Luo, Jian; Wen, Yan-yun; Wang, Yue; Yu, Jie

2012-06-01

To compare the difference in the clinical efficacy on nonspecific low back pain (NLBP) treated with the dragon-tiger fighting needling method, the uniform reinforcing-reducing method and the intermediate frequency physiotherapy. Ninety cases of NLBP were randomly divided into a dragon-tiger fighting needling group (group A), an uniform reinforcing-reducing needling group (group B) and an intermediate frequency physiotherapy group (group C), 30 cases in each one. In the group A, the dragon-tiger fighting needling method was used. In the group B, the uniform reinforcing-reducing method was applied. Two groups of acupoints were prescribed. One group included Shenshu (BL 23), Dachangshu (BL 25), Weizhong (BL 40) and Ashi points. The other group included Qihaishu (BL 24), Guanyuanshu (BL 26), Kunlun (BL 60), Yaoyangguan (GV 3). These two groups of acupoints were used alternatively in the above two groups. In the group C, the intermediate frequency physiotherapy was adopted in the pain area of the lumbar region. The treatment was given once per day in each group. Six treatments made one session. Totally, 2 sessions were required. The Visual Analogue Scale (VAS), the Oswestry Disability Index (ODD and the clinical efficacy were observed in each group. The scores of VAS and ODI were reduced obviously after treatment in each group (P < 0.05, P < 0.01). The score reducing in the group A was much more remarkable than those in the other two groups (all P < 0.05). The clinical curative rate was 30.0% (9/30), 23.3% (7/30) and 16.7% (5/30) in the group A, the group B and the group C, respectively. In comparison, the clinical efficacy in the group A was superior to that in either of the other groups (all P< 0.05). The dragon-tiger fighting needling method achieves the much better efficacy on NLBP compared with either the uniform reinforcing-reducing method or the intermediate frequency physiotherapy. It is one of the more effective needling method for analgesia.

Prostate Brachytherapy With Oblique Needles to Treat Large Glands and Overcome Pubic Arch Interference

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryu, Bon; Imaging Research Laboratories, Robarts Research Institute, University of Western Ontario, London, Ontario; Bax, Jeff

2012-08-01

Purpose: First, to show that low-dose-rate prostate brachytherapy plans using oblique needle trajectories are more successful than parallel trajectories for large prostates with pubic arch interference (PAI); second, to test the accuracy of delivering an oblique plan by using a three-dimensional (3D) transrectal ultrasonography (TRUS)-guided mechatronic system. Methods and Materials: Prostates were contoured for 5 subjects' 3D TRUS images showing a maximum PAI of {<=}1 cm and a prostate volume of <50 cc. Two planning studies were done. First, prostate contours were artificially enlarged to 45 to 80 cc in 5- to 10-cc increments for a single subject. Second, allmore » subject prostate contours were enlarged to 60 cc. For each study, three types of plans were manually created for comparison: a parallel needle template (PT) plan, a parallel needle no-template (PNT) plan, and an oblique needle no-template (OBL) plan. Needle positions and angles were not discretized for nontemplate plans. European Society for Therapeutic Radiology and Oncology dose-volume histogram guidelines, iodine-125 (145-Gy prescription, 0.43 U), and needle angles of <15 Degree-Sign were used. An OBL plan was delivered to a pubic arch containing a 60-cc prostate phantom that mimicked the anatomy of the subject with the greatest PAI (23% by volume). Results: In the increasing-prostate volume study, OBL plans were successful for prostates of {<=}80 cc, and PT plans were successful for prostates of <65 cc. In paired, one-sided t tests for the 60-cc volume study, OBL plans showed dosimetric improvements for all organs compared to both of the parallel type plans (p < 0.05); PNT plans showed a benefit only in planning target volumes receiving more than 100 Gy compared to PT plans. A computed tomography scan of the phantom showed submillimeter seed placement accuracy in all directions. Conclusion: OBL plans were significantly better than parallel plans, and an OBL plan was accurately delivered to a 60-cc prostate phantom with 23% PAI by volume.« less

Study on design and cutting parameters of rotating needles for core biopsy.

PubMed

Giovannini, Marco; Ren, Huaqing; Cao, Jian; Ehmann, Kornel

2018-06-15

Core needle biopsies are widely adopted medical procedures that consist in the removal of biological tissue to better identify a lesion or an abnormality observed through a physical exam or a radiology scan. These procedures can provide significantly more information than most medical tests and they are usually performed on bone lesions, breast masses, lymph nodes and the prostate. The quality of the samples mainly depends on the forces exerted by the needle during the cutting process. The reduction of these forces is critical to extract high-quality tissue samples. The most critical factors that affect the cutting forces are the geometry of the needle tip and its motion while it is penetrating the tissue. However, optimal needle tip configurations and cutting parameters are not well established for rotating insertions. In this paper, the geometry and cutting forces of hollow needles are investigated. The fundamental goal of this study is to provide a series of guidelines for clinicians and surgeons to properly select the optimal tip geometries and speeds. Analytical models related to the cutting angles of several needle tip designs are presented and compared. Several needle tip geometries were manufactured from a 14-gauge cannula, commonly adopted during breast biopsies. The needles were then tested at different speeds and on different phantom tissues. According to these experimental measurements recommendations were formulated for rotating needle insertions. The findings of this study can be applied and extended to several biopsy procedures in which a cannula is used to extract tissue samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

Multi-resolution Gabor wavelet feature extraction for needle detection in 3D ultrasound

NASA Astrophysics Data System (ADS)

Pourtaherian, Arash; Zinger, Svitlana; Mihajlovic, Nenad; de With, Peter H. N.; Huang, Jinfeng; Ng, Gary C.; Korsten, Hendrikus H. M.

2015-12-01

Ultrasound imaging is employed for needle guidance in various minimally invasive procedures such as biopsy guidance, regional anesthesia and brachytherapy. Unfortunately, a needle guidance using 2D ultrasound is very challenging, due to a poor needle visibility and a limited field of view. Nowadays, 3D ultrasound systems are available and more widely used. Consequently, with an appropriate 3D image-based needle detection technique, needle guidance and interventions may significantly be improved and simplified. In this paper, we present a multi-resolution Gabor transformation for an automated and reliable extraction of the needle-like structures in a 3D ultrasound volume. We study and identify the best combination of the Gabor wavelet frequencies. High precision in detecting the needle voxels leads to a robust and accurate localization of the needle for the intervention support. Evaluation in several ex-vivo cases shows that the multi-resolution analysis significantly improves the precision of the needle voxel detection from 0.23 to 0.32 at a high recall rate of 0.75 (gain 40%), where a better robustness and confidence were confirmed in the practical experiments.

[Percutaneous ablation of malignant kidney tumors in rabbits by low frequency radio energy].

PubMed

Moskovitz, B; Nativ, O; Sabo, E; Barbara, Y; Mordohovich, D; Kaftori, Y; Shalhav, A; Goldwasser, B

1998-01-01

Radio-frequency (RF) current has been used successfully to ablate normal human tissue. To investigate further the clinical application of this modality in tumors, we studied the potential of using RF percutaneously to destroy experimental kidney tumors. 35 outbred albino rabbits underwent direct-implantation of renal VX2 tumor during open surgery. After 21 days, ultrasonography was performed to show tumor presence and size. A shielded RF needle was designed to be inserted percutaneously through an introduction needle. An electrical insulation shield covering the RF needle was retractable, controlling the length of exposure of the RF needle inside the tissue. 22 days after tumor implantation, RF was applied via this special needle using a ZoMed International RF generator. In one group of rabbits the procedure was performed under direct vision during open surgery, while in another group treatment was percutaneous, the needle guided by palpation of the tumor. Rabbits were killed 3 days later and revealed 4-25 mm intra-tumoral RF-induced lesions. A direct relation was found between lesion size and the power and duration of RF applied (at 7.5 W, R = 0.48, and P = 0.32). Based on our preliminary results we can conclude that RF may have clinical applications in the near future for percutaneous local tumor control in parenchymal organs.

Convolution neural networks for real-time needle detection and localization in 2D ultrasound.

PubMed

Mwikirize, Cosmas; Nosher, John L; Hacihaliloglu, Ilker

2018-05-01

We propose a framework for automatic and accurate detection of steeply inserted needles in 2D ultrasound data using convolution neural networks. We demonstrate its application in needle trajectory estimation and tip localization. Our approach consists of a unified network, comprising a fully convolutional network (FCN) and a fast region-based convolutional neural network (R-CNN). The FCN proposes candidate regions, which are then fed to a fast R-CNN for finer needle detection. We leverage a transfer learning paradigm, where the network weights are initialized by training with non-medical images, and fine-tuned with ex vivo ultrasound scans collected during insertion of a 17G epidural needle into freshly excised porcine and bovine tissue at depth settings up to 9 cm and [Formula: see text]-[Formula: see text] insertion angles. Needle detection results are used to accurately estimate needle trajectory from intensity invariant needle features and perform needle tip localization from an intensity search along the needle trajectory. Our needle detection model was trained and validated on 2500 ex vivo ultrasound scans. The detection system has a frame rate of 25 fps on a GPU and achieves 99.6% precision, 99.78% recall rate and an [Formula: see text] score of 0.99. Validation for needle localization was performed on 400 scans collected using a different imaging platform, over a bovine/porcine lumbosacral spine phantom. Shaft localization error of [Formula: see text], tip localization error of [Formula: see text] mm, and a total processing time of 0.58 s were achieved. The proposed method is fully automatic and provides robust needle localization results in challenging scanning conditions. The accurate and robust results coupled with real-time detection and sub-second total processing make the proposed method promising in applications for needle detection and localization during challenging minimally invasive ultrasound-guided procedures.

A novel prototype 3/5 laparoscopic needle driver: A validation study with conventional laparoscopic needle driver.

PubMed

Ganpule, Arvind P; Deshmukh, Chaitanya S; Joshi, Tanmay

2018-01-01

The challenges in laparoscopic suturing include need to expertise to suture. Laparoscopic needle holder is a" key" instrument to accomplish this arduous task. The objective of this new invention was to develop a laparoscopic needle holder which would be adapted to avoid any wobble (with a shaft diameter same as a 5mm port), ensure accurate and dexterous suturing not just in adult patients but pediatric patients alike (with a short shaft diameter) and finally ensure seamless throw of knots with a narrow tip configuration. We did an initial evaluation to evaluate the validity of the prototype needle holder and its impact on laparoscopic suturing skills by experienced laparoscopic surgeons and novice laparoscopic Surgeons. Both the groups of surgeons performed two tasks. The first task was to grasp the needle and position it in an angle deemed ideal for suturing. The second task was to pass suture through two fixed points and make a single square knot. At the end of the tasks each participant was asked to complete a 5- point Likert's scale questionnaire (8 items; 4 items of handling and 4 items of suturing) rating each needle holder. In expert group, the mean time to complete task 1 was shorter with prototype 3/5 laparoscopic needle holder (11.8 sec Vs 20.8 sec). The mean time to complete task 2 was also shorter with prototype 3/5 laparoscopic needle holder (103.2 sec Vs 153.2 sec). In novice group, mean time to complete both the task was shorter with prototype 3/5 laparoscopic needle holder. The expert laparoscopic surgeons as well as novice laparoscopic surgeons performed laparoscopic suturing faster and with more ease while using the prototype 3/5 laparoscopic needle holder.

A novel prototype 3/5 laparoscopic needle driver: A validation study with conventional laparoscopic needle driver

PubMed Central

Ganpule, Arvind P.; Deshmukh, Chaitanya S.; Joshi, Tanmay

2018-01-01

Introduction: The challenges in laparoscopic suturing include need to expertise to suture. Laparoscopic needle holder is a ”key” instrument to accomplish this arduous task. Instrument: The objective of this new invention was to develop a laparoscopic needle holder which would be adapted to avoid any wobble (with a shaft diameter same as a 5mm port), ensure accurate and dexterous suturing not just in adult patients but pediatric patients alike (with a short shaft diameter) and finally ensure seamless throw of knots with a narrow tip configuration. Validation: We did an initial evaluation to evaluate the validity of the prototype needle holder and its impact on laparoscopic suturing skills by experienced laparoscopic surgeons and novice laparoscopic Surgeons. Both the groups of surgeons performed two tasks. The first task was to grasp the needle and position it in an angle deemed ideal for suturing. The second task was to pass suture through two fixed points and make a single square knot. At the end of the tasks each participant was asked to complete a 5- point Likert's scale questionnaire (8 items; 4 items of handling and 4 items of suturing) rating each needle holder. In expert group, the mean time to complete task 1 was shorter with prototype 3/5 laparoscopic needle holder (11.8 sec Vs 20.8 sec). The mean time to complete task 2 was also shorter with prototype 3/5 laparoscopic needle holder (103.2 sec Vs 153.2 sec). In novice group, mean time to complete both the task was shorter with prototype 3/5 laparoscopic needle holder. Conclusion: The expert laparoscopic surgeons as well as novice laparoscopic surgeons performed laparoscopic suturing faster and with more ease while using the prototype 3/5 laparoscopic needle holder. PMID:28782740

Three-dimensional path planning software-assisted transjugular intrahepatic portosystemic shunt: a technical modification.

PubMed

Tsauo, Jiaywei; Luo, Xuefeng; Ye, Linchao; Li, Xiao

2015-06-01

This study was designed to report our results with a modified technique of three-dimensional (3D) path planning software assisted transjugular intrahepatic portosystemic shunt (TIPS). 3D path planning software was recently developed to facilitate TIPS creation by using two carbon dioxide portograms acquired at least 20° apart to generate a 3D path for overlay needle guidance. However, one shortcoming is that puncturing along the overlay would be technically impossible if the angle of the liver access set and the angle of the 3D path are not the same. To solve this problem, a prototype 3D path planning software was fitted with a utility to calculate the angle of the 3D path. Using this, we modified the angle of the liver access set accordingly during the procedure in ten patients. Failure for technical reasons occurred in three patients (unsuccessful wedged hepatic venography in two cases, software technical failure in one case). The procedure was successful in the remaining seven patients, and only one needle pass was required to obtain portal vein access in each case. The course of puncture was comparable to the 3D path in all patients. No procedure-related complication occurred following the procedures. Adjusting the angle of the liver access set to match the angle of the 3D path determined by the software appears to be a favorable modification to the technique of 3D path planning software assisted TIPS.

Using insulin pen needles up to five times does not affect needle tip shape nor increase pain intensity.

PubMed

Puder, Jardena J; Atar, Michael; Muller, Beat; Pavan, Marco; Keller, Ulrich

2005-02-01

Reusing insulin pen needles could help to reduce the increasing economic burden of diabetes. We tested the hypothesis that reusing insulin pen needles leads to needle tip deformity and increased pain. Three blinded reviewers assessed 123 electron microscope pictures analyzing needle tip deformity of insulin pen needles used up to four times by diabetic subjects and up to five times by blinded non-diabetic volunteers. The estimated frequency of needle use was correlated to the actual number of needle use. Pain intensity and unpleasantness of each injection were measured by a visual analogue scale and their differences analyzed by Kruskal-Wallis analysis of variance. Unused needles could be differentiated visually from used needles. However, there was no correlation between the actual and guessed number of times a needle was used (r = 0.07, P = 0.2). Evaluating all 270 injections, neither pain intensity nor unpleasantness increased with repeated injections of the same needles in people with diabetes (P = 0.1 and 0.96) and in the volunteers (P = 0.63 and 0.92). Using pen needles four to five times does not lead to progressive needle tip deformity and does not increase pain intensity or unpleasantness, but could increase convenience and lead to substantial financial savings in Europe of around EUR 100 million/year.

Dimensions of stabident intraosseous perforators and needles.

PubMed

Ramlee, R A; Whitworth, J

2001-09-01

Problems can be encountered inserting intraosseous injection needles through perforation sites. This in vitro study examined the variability and size compatibility of Stabident intraosseous injection components. The diameters of 40 needles and perforators from a single Stabident kit were measured in triplicate with a toolmakers microscope. One-way ANOVA revealed that mean needle diameter (0.411 mm) was significantly narrower than mean perforator diameter (0.427 mm) (p < 0.001). A frequency distribution plot revealed that needle diameter followed a normal distribution, indicating tight quality control during manufacture. The diameter of perforators was haphazardly distributed, with a clustering of 15% at the lower limit of the size range. However on no occasion was the diameter of a perforator smaller than that of an injection needle. We conclude that components of the Stabident intraosseous anaesthetic system are size-compatible, but there is greater and more haphazard variability in the diameter of perforators than injection needles.

Tremor Frequency Assessment by iPhone® Applications: Correlation with EMG Analysis.

PubMed

Araújo, Rui; Tábuas-Pereira, Miguel; Almendra, Luciano; Ribeiro, Joana; Arenga, Marta; Negrão, Luis; Matos, Anabela; Morgadinho, Ana; Januário, Cristina

2016-10-19

Tremor frequency analysis is usually performed by EMG studies but accelerometers are progressively being more used. The iPhone® contains an accelerometer and many applications claim to be capable of measuring tremor frequency. We tested three applications in twenty-two patients with a diagnosis of PD, ET and Holmes' tremor. EMG needle assessment as well as accelerometry was performed at the same time. There was very strong correlation (Pearson >0.8, p < 0.001) between the three applications, the EMG needle and the accelerometry. Our data suggests the apps LiftPulse®, iSeismometer® and Studymytremor® are a reliable alternative to the EMG for tremor frequency assessment.

Acupuncture sensation during ultrasound guided acupuncture needling

PubMed Central

Park, Jongbae J.; Akazawa, Margeaux; Ahn, Jaeki; Beckman-Harned, Selena; Lin, Feng-Chang; Lee, Kwangjae; Fine, Jason; Davis, Robert T; Langevin, Helene

2014-01-01

Background Although acupuncture sensation (also known as de qi) is a cornerstone of traditional acupuncture therapy, most research has accepted the traditional method of defining acupuncture sensation only through subjective patient reports rather than on any quantifiable physiological basis. Purpose To preliminarily investigate the frequency of key sensations experienced while needling to specific, quantifiable tissue levels (TLs) guided by ultrasound (US) imaging. Methods Five participants received needling at two acupuncture points and two control points at four TLs. US scans were used to determine when each TL was reached. Each volunteer completed 32 sets of modified Southampton Needle Sensation Questionnaires. Part one of the study tested sensations experienced at each TL and part two compared the effect of oscillation alone versus oscillation + rotation. Results In all volunteers, the frequency of pricking, sharp sensations was significantly greater in shallower TLs than deeper (p=0.007); the frequency of sensations described as deep, dull and heavy, as spreading, and as electric shocks was significantly greater in deeper TLs than shallower (p=0.002). Sensations experienced did not significantly differ between real and control points within each of three TLs (p>0.05) except TL 4 (p=0.006). The introduction of needle rotation significantly increased deep, dull, heavy sensations, but not pricking and sharp sensations; within each level, the spectrum of sensation experienced during both oscillation + rotation and oscillation alone did not significantly differ between acupuncture and control points. Conclusion The preliminary study indicates a strong connection between acupuncture sensation and both tissue depth and needle rotation. Furthermore, the new methodology has been proven feasible. A further study with an objective measurement is warranted. PMID:21642648

Preclinical evaluation of an MRI-compatible pneumatic robot for angulated needle placement in transperineal prostate interventions.

PubMed

Tokuda, Junichi; Song, Sang-Eun; Fischer, Gregory S; Iordachita, Iulian I; Seifabadi, Reza; Cho, Nathan B; Tuncali, Kemal; Fichtinger, Gabor; Tempany, Clare M; Hata, Nobuhiko

2012-11-01

To evaluate the targeting accuracy of a small profile MRI-compatible pneumatic robot for needle placement that can angulate a needle insertion path into a large accessible target volume. We extended our MRI-compatible pneumatic robot for needle placement to utilize its four degrees-of-freedom (4-DOF) mechanism with two parallel triangular structures and support transperineal prostate biopsies in a closed-bore magnetic resonance imaging (MRI) scanner. The robot is designed to guide a needle toward a lesion so that a radiologist can manually insert it in the bore. The robot is integrated with navigation software that allows an operator to plan angulated needle insertion by selecting a target and an entry point. The targeting error was evaluated while the angle between the needle insertion path and the static magnetic field was between -5.7° and 5.7° horizontally and between -5.7° and 4.3° vertically in the MRI scanner after sterilizing and draping the device. The robot positioned the needle for angulated insertion as specified on the navigation software with overall targeting error of 0.8 ± 0.5mm along the horizontal axis and 0.8 ± 0.8mm along the vertical axis. The two-dimensional root-mean-square targeting error on the axial slices as containing the targets was 1.4mm. Our preclinical evaluation demonstrated that the MRI-compatible pneumatic robot for needle placement with the capability to angulate the needle insertion path provides targeting accuracy feasible for clinical MRI-guided prostate interventions. The clinical feasibility has to be established in a clinical study.

A novel curvature-controllable steerable needle for percutaneous intervention.

PubMed

Bui, Van Khuyen; Park, Sukho; Park, Jong-Oh; Ko, Seong Young

2016-08-01

Over the last few decades, flexible steerable robotic needles for percutaneous intervention have been the subject of significant interest. However, there still remain issues related to (a) steering the needle's direction with less damage to surrounding tissues and (b) increasing the needle's maximum curvature for better controllability. One widely used approach is to control the fixed-angled bevel-tip needle using a "duty-cycle" algorithm. While this algorithm has shown its applicability, it can potentially damage surrounding tissue, which has prevented the widespread adoption of this technology. This situation has motivated the development of a new steerable flexible needle that can change its curvature without axial rotation, while at the same time producing a larger curvature. In this article, we propose a novel curvature-controllable steerable needle. The proposed robotic needle consists of two parts: a cannula and a stylet with a bevel-tip. The curvature of the needle's path is controlled by a control offset, defined by the offset between the bevel-tip and the cannula. As a result, the necessity of rotating the whole needle's body is decreased. The duty-cycle algorithm is utilized to a limited degree to obtain a larger radius of curvature, which is similar to a straight path. The first prototype of 0.46 mm (outer diameter) was fabricated and tested with both in vitro gelatin phantom and ex vivo cow liver tissue. The maximum curvatures measured 0.008 mm(-1) in 6 wt% gelatin phantom, 0.0139 mm(-1) in 10 wt% gelatin phantom, and 0.0038 mm(-1) in cow liver. The experimental results show a linear relationship between the curvature and the control offset, which can be utilized for future implementation of this control algorithm. © IMechE 2016.

Electromagnetic wave extinction within a forested canopy

NASA Technical Reports Server (NTRS)

Karam, M. A.; Fung, A. K.

1989-01-01

A forested canopy is modeled by a collection of randomly oriented finite-length cylinders shaded by randomly oriented and distributed disk- or needle-shaped leaves. For a plane wave exciting the forested canopy, the extinction coefficient is formulated in terms of the extinction cross sections (ECSs) in the local frame of each forest component and the Eulerian angles of orientation (used to describe the orientation of each component). The ECSs in the local frame for the finite-length cylinders used to model the branches are obtained by using the forward-scattering theorem. ECSs in the local frame for the disk- and needle-shaped leaves are obtained by the summation of the absorption and scattering cross-sections. The behavior of the extinction coefficients with the incidence angle is investigated numerically for both deciduous and coniferous forest. The dependencies of the extinction coefficients on the orientation of the leaves are illustrated numerically.

CASPER: computer-aided segmentation of imperceptible motion-a learning-based tracking of an invisible needle in ultrasound.

PubMed

Beigi, Parmida; Rohling, Robert; Salcudean, Septimiu E; Ng, Gary C

2017-11-01

This paper presents a new micro-motion-based approach to track a needle in ultrasound images captured by a handheld transducer. We propose a novel learning-based framework to track a handheld needle by detecting microscale variations of motion dynamics over time. The current state of the art on using motion analysis for needle detection uses absolute motion and hence work well only when the transducer is static. We have introduced and evaluated novel spatiotemporal and spectral features, obtained from the phase image, in a self-supervised tracking framework to improve the detection accuracy in the subsequent frames using incremental training. Our proposed tracking method involves volumetric feature selection and differential flow analysis to incorporate the neighboring pixels and mitigate the effects of the subtle tremor motion of a handheld transducer. To evaluate the detection accuracy, the method is tested on porcine tissue in-vivo, during the needle insertion in the biceps femoris muscle. Experimental results show the mean, standard deviation and root-mean-square errors of [Formula: see text], [Formula: see text] and [Formula: see text] in the insertion angle, and 0.82, 1.21, 1.47 mm, in the needle tip, respectively. Compared to the appearance-based detection approaches, the proposed method is especially suitable for needles with ultrasonic characteristics that are imperceptible in the static image and to the naked eye.

Spin-echo small-angle neutron scattering (SESANS) measurements of needle-like crystallites of gelator compounds

NASA Astrophysics Data System (ADS)

Coumou, Pieter-Jan C. J. J.; Brizard, Aurelie M. A.; van Esch, Jan H.; de Schepper, Ignatz M.; Bouwman, Wim G.

2010-11-01

From dibenzoyl cystine, a low molecular weight gelator, we have prepared needle shaped crystals at relatively high concentrations. For the first time SESANS measurements are performed on objects with this geometry. From the measurements the average diameter can be seen directly. From a more careful analysis the width distribution is determined. The gel phase itself prepared at lower concentrations did not show any signal, in contrast to what one observes with conventional SANS. This shows the complementarity of SESANS and SANS.

Spin-wave interference in microscopic permalloy tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balhorn, Felix; Nagrodzki, Lukas; Mendach, Stefan

2013-06-03

We present permalloy coated needles which act as spin-wave resonators. The permalloy coated needles were investigated using microwave absorption spectroscopy. Thereby, we found up to three resonant modes which correspond to constructively interfering azimuthal spin waves. The resonant modes are well reproduced in calculations based on an analytical model for the spin-wave dispersion employing periodic boundary conditions. The dependence of the resonance frequencies on the needles' radii and the external magnetic field is demonstrated experimentally.

Percutaneous ablation of malignant liver tumor in rabbits using low radio frequency energy.

PubMed

Nativ, O; Moskovitz, B; Sabo, E; Shalhav, A; Kaftori, J; Barbara, Y; Mordohovich, D; Goldwasser, B

1996-09-01

Radio frequency (RF) current has been used successfully to ablate normal human tissue. To further investigate the clinical application of this modality in tumors we studied the potential of using RF percutaneously to destroy experimental liver tumors. Thirty five outbred albino rabbits underwent liver VX2 tumor direct-implantation during open surgery. After 21 days ultrasonography was performed revealing tumor presence and size. A shielded RF needle was designed so that it could be inserted percutaneously through an introducing needle, and an electrical insulation shield covering the RF needle could be retracted to control the length of the exposed RF needle inside the tissue. Twenty two days after tumor implantation RF was applied via the aforementioned needle using a ZoMed International RF generator. In one group of rabbits the procedure was performed under direct vision during open surgery and on the other group treatment was applied percutaneously, guiding the needle by tumor palpation. Rabbits were killed 3 days later and pathology revealed 4 to 25 mm intratumoral RF induced lesions. A direct relation was found between lesion size, power and duration of RF application (At 7.5 W, r = 0.48, p = 0.032). Based on our preliminary results we may conclude that RF may have clinical application in the near future for percutaneous local tumor control in parenchymal organs.

A novel 3D guidance system using augmented reality for percutaneous vertebroplasty: technical note.

PubMed

Abe, Yuichiro; Sato, Shigenobu; Kato, Koji; Hyakumachi, Takahiko; Yanagibashi, Yasushi; Ito, Manabu; Abumi, Kuniyoshi

2013-10-01

Augmented reality (AR) is an imaging technology by which virtual objects are overlaid onto images of real objects captured in real time by a tracking camera. This study aimed to introduce a novel AR guidance system called virtual protractor with augmented reality (VIPAR) to visualize a needle trajectory in 3D space during percutaneous vertebroplasty (PVP). The AR system used for this study comprised a head-mount display (HMD) with a tracking camera and a marker sheet. An augmented scene was created by overlaying the preoperatively generated needle trajectory path onto a marker detected on the patient using AR software, thereby providing the surgeon with augmented views in real time through the HMD. The accuracy of the system was evaluated by using a computer-generated simulation model in a spine phantom and also evaluated clinically in 5 patients. In the 40 spine phantom trials, the error of the insertion angle (EIA), defined as the difference between the attempted angle and the insertion angle, was evaluated using 3D CT scanning. Computed tomography analysis of the 40 spine phantom trials showed that the EIA in the axial plane significantly improved when VIPAR was used compared with when it was not used (0.96° ± 0.61° vs 4.34° ± 2.36°, respectively). The same held true for EIA in the sagittal plane (0.61° ± 0.70° vs 2.55° ± 1.93°, respectively). In the clinical evaluation of the AR system, 5 patients with osteoporotic vertebral fractures underwent VIPAR-guided PVP from October 2011 to May 2012. The postoperative EIA was evaluated using CT. The clinical results of the 5 patients showed that the EIA in all 10 needle insertions was 2.09° ± 1.3° in the axial plane and 1.98° ± 1.8° in the sagittal plane. There was no pedicle breach or leakage of polymethylmethacrylate. VIPAR was successfully used to assist in needle insertion during PVP by providing the surgeon with an ideal insertion point and needle trajectory through the HMD. The findings indicate that AR guidance technology can become a useful assistive device during spine surgeries requiring percutaneous procedures.

In vitro fenestration of aortic stent-grafts: implications of puncture methods for in situ fenestration durability.

PubMed

Riga, Celia V; Bicknell, Colin D; Basra, Melvinder; Hamady, Mohamad; Cheshire, Nicholas J W

2013-08-01

To investigate the quality of stent-graft fenestrations created in vitro using different needle puncture and balloon dilation angles in different commercial endografts. Fenestrations were made in a standardized fashion in 3 different endograft types: Talent monofilament twill woven polyester, Zenith multifilament tubular woven polyester, and Endofit thin-walled expanded polytetrafluoroethylene (PTFE). Punctures were made at 30°, 60°, and 90° angles using a 20-G needle and dilated using 6-mm standard and 7-mm cutting balloons; at least 6 fenestrations were made at each angle with standard balloons and at least 6 with cutting balloons. The 137 fenestrations were examined under light microscopy; quantitative and qualitative digital image analysis was performed to determine size, shape, and fenestration quality. PTFE grafts were easier to puncture/dilate, resulting in larger, elliptical fenestrations with overall better quality than the Dacron grafts; however, the puncture/dilation angle made an impact on the shape and quality of fenestrations. A significant number of fabric tears were observed in PTFE fabric at <90° puncture/dilation angles compared to Dacron grafts. In Dacron grafts, fenestration quality was significantly higher with 90° puncture/dilation angles (higher in Talent grafts). Cutting balloon use resulted in significantly more fabric tears and poor quality fenestrations in all graft types. Different endografts behave significantly differently when fenestrations are fashioned. Optimum puncture/dilation is important when considering in vivo fenestration techniques. Improvements in instrumentation, materials, and techniques are required to make this a reliable and reproducible endovascular option.

Three-Dimensional Path Planning Software-Assisted Transjugular Intrahepatic Portosystemic Shunt: A Technical Modification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsauo, Jiaywei, E-mail: 80732059@qq.com; Luo, Xuefeng, E-mail: luobo-913@126.com; Ye, Linchao, E-mail: linchao.ye@siemens.com

2015-06-15

PurposeThis study was designed to report our results with a modified technique of three-dimensional (3D) path planning software assisted transjugular intrahepatic portosystemic shunt (TIPS).Methods3D path planning software was recently developed to facilitate TIPS creation by using two carbon dioxide portograms acquired at least 20° apart to generate a 3D path for overlay needle guidance. However, one shortcoming is that puncturing along the overlay would be technically impossible if the angle of the liver access set and the angle of the 3D path are not the same. To solve this problem, a prototype 3D path planning software was fitted with a utility to calculate themore » angle of the 3D path. Using this, we modified the angle of the liver access set accordingly during the procedure in ten patients.ResultsFailure for technical reasons occurred in three patients (unsuccessful wedged hepatic venography in two cases, software technical failure in one case). The procedure was successful in the remaining seven patients, and only one needle pass was required to obtain portal vein access in each case. The course of puncture was comparable to the 3D path in all patients. No procedure-related complication occurred following the procedures.ConclusionsAdjusting the angle of the liver access set to match the angle of the 3D path determined by the software appears to be a favorable modification to the technique of 3D path planning software assisted TIPS.« less

Effect of needle size and type, reuse of needles, insertion speed, and removal of hair on contamination of joints with tissue debris and hair after arthrocentesis.

PubMed

Adams, Stephen B; Moore, George E; Elrashidy, Mohammed; Mohamed, Ahmed; Snyder, Paul W

2010-08-01

To assess joint contamination with tissue and hair after arthrocentesis of equine fetlock joints. Experimental. Limb specimens from 8 equine cadavers. Soft tissues including the joint capsule were harvested from the dorsal aspect of the fetlock joints and mounted on a wooden frame. Needles inserted through the joint tissue preparation were flushed into tissue culture plates that were examined for tissue and hair debris. Variables evaluated were gauge and type of needle (16, 18, 20, and 22 G sharp disposable needles and 20 G disposable spinal needles with stylet), number of times each needle was used (1, 2, 3, 4), length of hair (unclipped, clipped, shaved with razor), and needle insertion speed (fast, slow). Descriptive and statistical evaluations were performed. Tissue contamination was identified in 1145 of 1260 wells and hair contamination was identified in 384 of 1260 wells. Twenty gauge needles inserted through unclipped hair resulted in the least amount of hair contamination. Compared with 20 G needles with fast insertion 1 time through unclipped hair the odds ratios for contamination with hair were significantly greater for 16 G sharp disposable needles, 20 G spinal needles, clipped hair, shaved hair, and reuse of the needles. Spinal needles inserted through unclipped hair transferred many long hairs into the joint space. Reuse of needles for arthrocentesis should be avoided. Removal of hair is not indicated for arthrocentesis with sharp injection needles but is recommended when using spinal needles with stylets. Joint contamination with hair and tissue debris will be decreased by specific needle insertion techniques. Decreased contamination of joints may reduce the frequency of joint infections after arthrocentesis.

Incidence of tissue coring during transseptal catheterization when using electrocautery and a standard transseptal needle.

PubMed

Greenstein, Eugene; Passman, Rod; Lin, Albert C; Knight, Bradley P

2012-04-01

The application of radiofrequency electrocautery to a standard, open-ended transseptal needle has been used to facilitate transseptal puncture (TSP). The purpose of this study was to determine the incidence of cardiac tissue coring when this technique is used. A model using excised swine hearts submerged in a saline-filled basin was developed to simulate TSP with electrocautery and a standard transseptal needle. Punctures were performed without the use of electrocautery and by delivering radiofrequency energy to the transseptal needle using a standard electrocautery pen at 3 target sites (fossa ovalis, non-fossa ovalis septum, and aorta). The tissue of the submerged heart was gently tented, and the needle was advanced on delivery of radiofrequency. The devices were retracted, and the needle was flushed in a collection basin. None of the TSPs without cautery caused tissue coring. For TSPs using electrocautery, the frequency of coring was at least 21% for any puncture permutation used in the study and averaged 37% at septal sites (P<0.001 compared with punctures without cautery). Tissue coring occurred in 33 of 96 (35%) punctures through the fossa ovalis and in 38 of 96 (40%) punctures through non-fossa ovalis septum. The frequency of tissue coring at aortic sites was 62 of 96 (65%), which was significantly higher than at the septal sites (P<0.001). In an animal preparation, TSP at the level of the fossa ovalis using electrocautery and a standard open-ended Brockenbrough needle resulted in coring of the septal tissue in 35% of cases (33 of 96 punctures).

Tool Indicates Contact Angles In Bearing Raceways

NASA Technical Reports Server (NTRS)

Akian, Richard A.; Butner, Myles F.

1995-01-01

Tool devised for use in measuring contact angles between balls and races in previously operated ball bearings. Used on both inner and outer raceways of bearings having cross-sectional widths between approximately 0.5 and 2.0 in. Consists of integral protractor mounted in vertical plane on bracket equipped with leveling screws and circular level indicator. Protractor includes rotatable indicator needle and set of disks of various sizes to fit various raceway curvatures.

Foramen ovale puncture, lesioning accuracy, and avoiding complications: microsurgical anatomy study with clinical implications.

PubMed

Peris-Celda, Maria; Graziano, Francesca; Russo, Vittorio; Mericle, Robert A; Ulm, Arthur J

2013-11-01

Foramen ovale (FO) puncture allows for trigeminal neuralgia treatment, FO electrode placement, and selected biopsy studies. The goals of this study were to demonstrate the anatomical basis of complications related to FO puncture, and provide anatomical landmarks for improvement of safety, selective lesioning of the trigeminal nerve (TN), and optimal placement of electrodes. Both sides of 50 dry skulls were studied to obtain the distances from the FO to relevant cranial base references. A total of 36 sides from 18 formalin-fixed specimens were dissected for Meckel cave and TN measurements. The best radiographic projection for FO visualization was assessed in 40 skulls, and the optimal trajectory angles, insertion depths, and topographies of the lesions were evaluated in 17 specimens. In addition, the differences in postoperative pain relief after the radiofrequency procedure among different branches of the TN were statistically assessed in 49 patients to determine if there was any TN branch less efficiently targeted. Most severe complications during FO puncture are related to incorrect needle placement intracranially or extracranially. The needle should be inserted 25 mm lateral to the oral commissure, forming an approximately 45° angle with the hard palate in the lateral radiographic view, directed 20° medially in the anteroposterior view. Once the needle reaches the FO, it can be advanced by 20 mm, on average, up to the petrous ridge. If the needle/radiofrequency electrode tip remains more than 18 mm away from the midline, injury to the cavernous carotid artery is minimized. Anatomically there is less potential for complications when the needle/radiofrequency electrode is advanced no more than 2 mm away from the clival line in the lateral view, when the needle pierces the medial part of the FO toward the medial part of the trigeminal impression in the petrous ridge, and no more than 4 mm in the lateral part. The 40°/45° inferior transfacial-20° oblique radiographic projection visualized 96.2% of the FOs in dry skulls, and the remainder were not visualized in any other projection of the radiograph. Patients with V1 involvement experienced postoperative pain more frequently than did patients with V2 or V3 involvement. Anatomical targeting of V1 in specimens was more efficiently achieved by inserting the needle in the medial third of the FO; for V2 targeting, in the middle of the FO; and for V3 targeting, in the lateral third of the FO. Knowledge of the extracranial and intracranial anatomical relationships of the FO is essential to understanding and avoiding complications during FO puncture. These data suggest that better radiographic visualization of the FO can improve lesioning accuracy depending on the part of the FO to be punctured. The angles and safety distances obtained may help the neurosurgeon minimize complications during FO puncture and TN lesioning.

Facile fabrication of super-hydrophobic nano-needle arrays via breath figures method.

PubMed

Kim, Jiseok; Lew, Brian; Kim, Woo Soo

2011-12-06

Super-hydrophobic surfaces which have been fabricated by various methods such as photolithography, chemical treatment, self-assembly, and imprinting have gained enormous attention in recent years. Especially 2D arrays of nano-needles have been shown to have super-hydrophobicity due to their sharp surface roughness. These arrays can be easily generated by removing the top portion of the honeycomb films prepared by the breath figures method. The hydrophilic block of an amphiphilic polymer helps in the fabrication of the nano-needle arrays through the production of well-ordered honeycomb films and good adhesion of the film to a substrate. Anisotropic patterns with water wettability difference can be useful for patterning cells and other materials using their selective growth on the hydrophilic part of the pattern. However, there has not been a simple way to generate patterns with highly different wettability. Mechanical stamping of the nano-needle array with a polyurethane stamp might be the simplest way to fabricate patterns with wettability difference. In this study, super-hydrophobic nano-needle arrays were simply fabricated by removing the top portion of the honeycomb films. The maximum water contact angle obtained with the nano-needle array was 150°. By controlling the pore size and the density of the honeycomb films, the height, width, and density of nano-needle arrays were determined. Anisotropic patterns with different wettability were fabricated by simply pressing the nano-needle array at ambient temperature with polyurethane stamps which were flexible but tough. Mechanical stamping of nano-needle arrays with micron patterns produced hierarchical super-hydrophobic structures.PACS: 05.70.Np, 68.55.am, 68.55.jm.

Facile fabrication of super-hydrophobic nano-needle arrays via breath figures method

PubMed Central

2011-01-01

Super-hydrophobic surfaces which have been fabricated by various methods such as photolithography, chemical treatment, self-assembly, and imprinting have gained enormous attention in recent years. Especially 2D arrays of nano-needles have been shown to have super-hydrophobicity due to their sharp surface roughness. These arrays can be easily generated by removing the top portion of the honeycomb films prepared by the breath figures method. The hydrophilic block of an amphiphilic polymer helps in the fabrication of the nano-needle arrays through the production of well-ordered honeycomb films and good adhesion of the film to a substrate. Anisotropic patterns with water wettability difference can be useful for patterning cells and other materials using their selective growth on the hydrophilic part of the pattern. However, there has not been a simple way to generate patterns with highly different wettability. Mechanical stamping of the nano-needle array with a polyurethane stamp might be the simplest way to fabricate patterns with wettability difference. In this study, super-hydrophobic nano-needle arrays were simply fabricated by removing the top portion of the honeycomb films. The maximum water contact angle obtained with the nano-needle array was 150°. By controlling the pore size and the density of the honeycomb films, the height, width, and density of nano-needle arrays were determined. Anisotropic patterns with different wettability were fabricated by simply pressing the nano-needle array at ambient temperature with polyurethane stamps which were flexible but tough. Mechanical stamping of nano-needle arrays with micron patterns produced hierarchical super-hydrophobic structures. PACS: 05.70.Np, 68.55.am, 68.55.jm PMID:22145673

Needle segmentation using 3D Hough transform in 3D TRUS guided prostate transperineal therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiu Wu; Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario N6A 5K8; Yuchi Ming

Purpose: Prostate adenocarcinoma is the most common noncutaneous malignancy in American men with over 200 000 new cases diagnosed each year. Prostate interventional therapy, such as cryotherapy and brachytherapy, is an effective treatment for prostate cancer. Its success relies on the correct needle implant position. This paper proposes a robust and efficient needle segmentation method, which acts as an aid to localize the needle in three-dimensional (3D) transrectal ultrasound (TRUS) guided prostate therapy. Methods: The procedure of locating the needle in a 3D TRUS image is a three-step process. First, the original 3D ultrasound image containing a needle is cropped;more » the cropped image is then converted to a binary format based on its histogram. Second, a 3D Hough transform based needle segmentation method is applied to the 3D binary image in order to locate the needle axis. The position of the needle endpoint is finally determined by an optimal threshold based analysis of the intensity probability distribution. The overall efficiency is improved through implementing a coarse-fine searching strategy. The proposed method was validated in tissue-mimicking agar phantoms, chicken breast phantoms, and 3D TRUS patient images from prostate brachytherapy and cryotherapy procedures by comparison to the manual segmentation. The robustness of the proposed approach was tested by means of varying parameters such as needle insertion angle, needle insertion length, binarization threshold level, and cropping size. Results: The validation results indicate that the proposed Hough transform based method is accurate and robust, with an achieved endpoint localization accuracy of 0.5 mm for agar phantom images, 0.7 mm for chicken breast phantom images, and 1 mm for in vivo patient cryotherapy and brachytherapy images. The mean execution time of needle segmentation algorithm was 2 s for a 3D TRUS image with size of 264 Multiplication-Sign 376 Multiplication-Sign 630 voxels. Conclusions: The proposed needle segmentation algorithm is accurate, robust, and suitable for 3D TRUS guided prostate transperineal therapy.« less

Measurements of attenuation coefficient for evaluating the hardness of a cataract lens by a high-frequency ultrasonic needle transducer.

PubMed

Huang, Chih-Chung; Chen, Ruimin; Tsui, Po-Hsiang; Zhou, Qifa; Humayun, Mark S; Shung, K Kirk

2009-10-07

A cataract is a clouding of the lens in the eye that affects vision. Phacoemulsification is the mostly common surgical method for treating cataracts, and determining that the optimal phacoemulsification energy is dependent on measuring the hardness of the lens. This study explored the use of an ultrasound needle transducer for invasive measurements of ultrasound attenuation coefficient to evaluate the hardness of the cataract lens. A 47 MHz high-frequency needle transducer with a diameter of 0.9 mm was fabricated by a polarized PMN-33%PT single crystal in the present study. The attenuation coefficients at different stages of an artificial porcine cataract lens were measured using the spectral shift approach. The hardness of the cataract lens was also evaluated by mechanical measurement of its elastic properties. The results demonstrated that the ultrasonic attenuation coefficient was increased from 0.048 +/- 0.02 to 0.520 +/- 0.06 dB mm(-1) MHz(-1) corresponding to an increase in Young's modulus from 6 +/- 0.4 to 96 +/- 6.2 kPa as the cataract further developed. In order to evaluate the feasibility of combining needle transducer and phacoemulsification probe for real-time measurement during cataract surgery, the needle transducer was mounted on the phacoemulsification probe for a vibration test. The results indicated that there was no apparent damage to the tip of the needle transducer and the pulse-echo test showed that a good performance in sensitivity was maintained after the vibration test.

Using a Motion Sensor-Equipped Smartphone to Facilitate CT-Guided Puncture.

PubMed

Hirata, Masaaki; Watanabe, Ryouhei; Koyano, Yasuhiro; Sugata, Shigenori; Takeda, Yukie; Nakamura, Seiji; Akamune, Akihisa; Tsuda, Takaharu; Mochizuki, Teruhito

2017-04-01

To demonstrate the use of "Smart Puncture," a smartphone application to assist conventional CT-guided puncture without CT fluoroscopy, and to describe the advantages of this application. A puncture guideline is displayed by entering the angle into the application. Regardless of the angle at which the device is being held, the motion sensor ensures that the guideline is displayed at the appropriate angle with respect to gravity. The angle of the smartphone's liquid crystal display (LCD) is also detected, preventing needle deflection from the CT slice image. Physicians can perform the puncture procedure by advancing the needle using the guideline while the smartphone is placed adjacent to the patient. In an experimental puncture test using a sponge as a target, the target was punctured at 30°, 50°, and 70° when the device was tilted to 0°, 15°, 30°, and 45°, respectively. The punctured target was then imaged with a CT scan, and the puncture error was measured. The mean puncture error in the plane parallel to the LCD was less than 2°, irrespective of device tilt. The mean puncture error in the sagittal plane was less than 3° with no device tilt. However, the mean puncture error tended to increase when the tilt was increased. This application can transform a smartphone into a valuable tool that is capable of objectively and accurately assisting CT-guided puncture procedures.

Needle tip localization using stylet vibration.

PubMed

Harmat, Adam; Rohling, Robert N; Salcudean, Septimiu E

2006-09-01

Power Doppler ultrasound is used to localize the tip of a needle by detecting physical vibrations. Two types of vibrations are investigated, lateral and axial. The lateral vibrations are created by rotating a stylet, whose tip is slightly bent, inside a stationary cannula while the stylet is completely within the cannula. The minute deflection at the needle tip when rotated causes tissue motion. The axial vibration is induced by extending and retracting a straight stylet inside a stationary cannula. The stylet's tip makes contact with the tissue and causes it to move. The lateral vibration method was found to perform approximately the same under a variety of configurations (e.g., different insertion angles and depths) and better than the axial vibration method. Tissue stiffness affects the performance of the lateral vibration method, but good images can be obtained through proper tuning of the ultrasound machine.

[Teaching design of mastering scalp acupuncture fast].

PubMed

Li, Jie; Niu, Wenmin

2016-05-01

Scalp acupuncture is a method of treating whole-body diseases. The author takes the easy positioning of scalp acupuncture as starting point, covers the positioning of scalp acupuncture and needle insertion points, acupuncture manipulation and the selection of acupoints, so as to introduce the design of teaching the international standardized scalp acupuncture with texts and illustrations. The positions of scalp acupuncture are 4 lines in frontal area, 5 lines in parietal area, 2 lines in temporal area and 3 lines in occipital area. The needle insertion angle is 30° to the skin. Acupoints can be selected crossly and correspondingly in clinic.

Proposed catalog of the neuroanatomy and the stratified anatomy for the 361 acupuncture points of 14 channels.

PubMed

Chapple, Will

2013-10-01

In spite of the extensive research on acupuncture mechanisms, no comprehensive and systematic peer-reviewed reference list of the stratified anatomical and the neuroanatomical features of all 361 acupuncture points exists. This study creates a reference list of the neuroanatomy and the stratified anatomy for each of the 361 acupuncture points on the 14 classical channels and for 34 extra points. Each acupuncture point was individually assessed to relate the point's location to anatomical and neuroanatomical features. The design of the catalogue is intended to be useful for any style of acupuncture or Oriental medicine treatment modality. The stratified anatomy was divided into shallow, intermediate and deep insertion. A separate stratified anatomy was presented for different needle angles and directions. The following are identified for each point: additional specifications for point location, the stratified anatomy, motor innervation, cutaneous nerve and sensory innervation, dermatomes, Langer's lines, and somatotopic organization in the primary sensory and motor cortices. Acupuncture points for each muscle, dermatome and myotome are also reported. This reference list can aid clinicians, practitioners and researchers in furthering the understanding and accurate practice of acupuncture. Additional research on the anatomical variability around acupuncture points, the frequency of needle contact with an anatomical structure in a clinical setting, and conformational imaging should be done to verify this catalogue. Copyright © 2013. Published by Elsevier B.V.

Decreased Spontaneous Electrical Activity and Acetylcholine at Myofascial Trigger Spots after Dry Needling Treatment: A Pilot Study.

PubMed

Liu, Qing-Guang; Liu, Lin; Huang, Qiang-Min; Nguyen, Thi-Tham; Ma, Yan-Tao; Zhao, Jia-Min

2017-01-01

The aims of this study are to investigate the changes in spontaneous electrical activities (SEAs) and in acetylcholine (ACh), acetylcholine receptor (AChR), and acetylcholine esterase (AChE) levels after dry needling at myofascial trigger spots in model rats. Forty-eight male Sprague-Dawley rats were divided into four groups. Thirty-six rats were assigned to three model groups, which underwent MTrSs modeling intervention. Twelve rats were assigned to the blank control (BC) group. After model construction, the 36 model rats were randomly subdivided into three groups according to treatment: MTrSs model control (MC) and two dry needling groups. One dry needling group received puncturing at MTrSs (DN-M), whereas the other underwent puncturing at non-MTrSs (DN-nM). Dry needling treatment will last for two weeks, once a week. SEAs and ACh, AChR, and AChE levels were measured after one-week rest of dry needling treatment. The amplitudes and frequencies of endplate noise (EPN) and endplate spike (EPS) significantly decreased after dry needling treatment in the DN-M group. Moreover, ACh and AChR levels significantly decreased, whereas AChE significantly increased after dry needling treatment in the DN-M group. Dry needling at the exact MTrSs is more effective than dry needling at non-MTrSs.

Decreased Spontaneous Electrical Activity and Acetylcholine at Myofascial Trigger Spots after Dry Needling Treatment: A Pilot Study

PubMed Central

2017-01-01

Objective The aims of this study are to investigate the changes in spontaneous electrical activities (SEAs) and in acetylcholine (ACh), acetylcholine receptor (AChR), and acetylcholine esterase (AChE) levels after dry needling at myofascial trigger spots in model rats. Materials and Methods Forty-eight male Sprague-Dawley rats were divided into four groups. Thirty-six rats were assigned to three model groups, which underwent MTrSs modeling intervention. Twelve rats were assigned to the blank control (BC) group. After model construction, the 36 model rats were randomly subdivided into three groups according to treatment: MTrSs model control (MC) and two dry needling groups. One dry needling group received puncturing at MTrSs (DN-M), whereas the other underwent puncturing at non-MTrSs (DN-nM). Dry needling treatment will last for two weeks, once a week. SEAs and ACh, AChR, and AChE levels were measured after one-week rest of dry needling treatment. Results The amplitudes and frequencies of endplate noise (EPN) and endplate spike (EPS) significantly decreased after dry needling treatment in the DN-M group. Moreover, ACh and AChR levels significantly decreased, whereas AChE significantly increased after dry needling treatment in the DN-M group. Conclusion Dry needling at the exact MTrSs is more effective than dry needling at non-MTrSs. PMID:28592980

Noncontact Viscoelastic Imaging of Living Cells Using a Long-Needle Atomic Force Microscope with Dual-Frequency Modulation

NASA Astrophysics Data System (ADS)

Guan, Dongshi; Charlaix, Elisabeth; Qi, Robert Z.; Tong, Penger

2017-10-01

Imaging of surface topography and elasticity of living cells can provide insight into the roles played by the cells' volumetric and mechanical properties and their response to external forces in regulating the essential cellular events and functions. Here, we report a unique technique of noncontact viscoelastic imaging of live cells using atomic force microscopy (AFM) with a long-needle glass probe. Because only the probe tip is placed in a liquid medium near the cell surface, the AFM cantilever in air functions well under dual-frequency modulation, retaining its high-quality resonant modes. The probe tip interacts with the cell surface through a minute hydrodynamic flow in the nanometer-thin gap region between them without physical contact. Quantitative measurements of the cell height, volume, and Young's modulus are conducted simultaneously. The experiment demonstrates that the long-needle AFM has a wide range of applications in the study of cell mechanics.

[Radiofrequency ablation as a palliative therapy option in ENT tumors: in vivo and in vitro testing].

PubMed

Bucher, S; Hornung, J; Bonkowsky, V; Iro, H; Zenk, J

2010-04-01

High frequency thermotherapy (HFTT) is an established palliative therapy for hepatic malignancies. An in vivo and in vitro trial examined the preconditions for the application of HFTT with liquid-cooled wet electrodes for minimally invasive palliation of head and neck tumors. HFTT was applied with needle electrodes, cooled with isotonic saline solution, and a high-frequency generator (Elektrotom HiTT 106, Berchtold, Tuttlingen) to porcine tongue and narcotized, juvenile domestic pigs to the tongue and neck, and monitored in realtime by B-mode ultrasound. The direction of spread of the hyperthermic zone is well observed using ultrasound. Determining the direction of spread is not possible with cooled-tip electrode needles. Severe complications were not observed during the application. RFA with liquid-cooled needle applicators is not safely applicable for the therapy of head and neck tumors.

SU-E-J-81: Beveled Needle Tip Detection Error in Ultrasound-Guided Prostate Brachytherapy.

PubMed

Leu, S; Ruiz, B; Podder, T

2012-06-01

To quantify the needle tip detection errors in ultrasound images due to bevel-tip orientation in relation to the location on template grid. Transrectal ultrasound (TRUS) system (BK Medical) with physical template grid and 18-gauge bevel-tip (20-deg beveled angle) brachytherapy needle (Bard Medical, Covington, GA) were used. The TRUS was set at 6.5MHz in water phantom at 40°C and measurements were taken with 50% and 100% TRUS gains. Needles were oriented with bevel-tip facing up (0-degree) and inserted through template grid-holes. Reference needle depths were measured when needle tip image intensity was bright enough for potentially consistent readings. High-resolution digital vernier caliper was used to measure needle depth. Needle bevel-tip orientation was then changed to bevel down (by rotating 180-degree) and needle depth was adjusted by retracting so that the needle-tip image intensity appeared similar to when the needle bevel-tip was at 0-degree orientation. Clinically relevant locations were considered for needle placement on the template grids (1st row to 9th row, and 'a-f' columns). For 50% TRUS gain, bevel tip detection errors/differences were 0.69±0.30mm (1st row) to 3.23±0.22mm (9th row) and 0.78±0.71mm (1st row) to 4.14±0.56mm (9th row) in columns 'a' and 'D', respectively. The corresponding errors for 100% TRUS gain were 0.57±0.25mm to 5.24±0.36mm and 0.84±0.30mm to 4.2±0.20mm in columns 'a' and 'D', respectively. These errors/differences varied linearly for grid-hole locations on the rows and columns in between, smaller to large depending on distance from the TRUS probe. Observed no effect of gains (50% vs. 100%) along 'D' column, which was directly above the TRUS probe. Experiment results revealed that the beveled needle tip orientation could significantly impact the detection accuracy of the needle tips, based on which the seeds might be delivered. These errors may lead to considerable dosimetric deviations in prostate brachytherapy seed implantation. © 2012 American Association of Physicists in Medicine.

Needle Revision With 5-fluorouracil for the Treatment of Ahmed Glaucoma Valve Filtering Blebs: 5-Fluoruracil Needling Revision can be a Useful and Safe Tool in the Management of Failing Ahmed Glaucoma Valve Filtering Blebs.

PubMed

Quaranta, Luciano; Floriani, Irene; Hollander, Lital; Poli, Davide; Katsanos, Andreas; Konstas, Anastasios G P

2016-04-01

To determine the outcome of needling with adjunctive 5-fluorouracil (5-FU) in patients with a failing Ahmed glaucoma valve (AGV) implant, and to identify predictors of long-term intraocular pressure (IOP) control. A prospective observational study was performed on consecutive patients with medically uncontrolled primary open-angle glaucoma (POAG) with AGV encapsulation or fibrosis and inadequate IOP control. Bleb needling with 5-FU injection (0.1 mL of 50 mg/mL) was performed at the slit-lamp. Patients were examined 1 week following the needling, and then at months 1, 3, and 6. Subsequent follow-up visits were scheduled at 6-month intervals for at least 2 years. Needling with 5-FU was repeated no more than twice during the first 3 months of the follow-up. Procedure outcome was determined on the basis of the recorded IOP levels. Thirty-six patients with an encapsulated or fibrotic AGV underwent 67procedures (mean 1.86 ± 0.83). Complete success, defined as IOP ≤ 18 mm Hg without medications, was obtained in 25% at 24 months of observation. The cumulative proportion of cases achieving either qualified (ie, IOP ≤ 18 mm Hg with medications) or complete success at 24 months of observation was 72.2%. In a univariate Cox proportional hazards model, age was the only variable that independently influenced the risk of failing 5-FU needling revision. Fourteen eyes (38.8%) had a documented complication. Needling over the plate of an AGV supplemented with 5-FU is an effective and safe choice in a significant proportion of POAG patients with elevated IOP due to encapsulation or fibrosis.

Simultaneously measured signals in scanning probe microscopy with a needle sensor: frequency shift and tunneling current.

PubMed

Morawski, Ireneusz; Voigtländer, Bert

2010-03-01

We present combined noncontact scanning force microscopy and tunneling current images of a platinum(111) surface obtained by means of a 1 MHz quartz needle sensor. The low-frequency circuit of the tunneling current was combined with a high-frequency signal of the quartz resonator enabling full electrical operation of the sensor. The frequency shift and the tunneling current were detected simultaneously, while the feedback control loop of the topography signal was fed using one of them. In both cases, the free signal that was not connected to the feedback loop reveals proportional-integral controller errorlike behavior, which is governed by the time derivative of the topography signal. A procedure is proposed for determining the mechanical oscillation amplitude by utilizing the tunneling current also including the average tip-sample work function.

Comparison of design features and mechanical properties of commercially available Veress needles.

PubMed

Schramel, Johannes P; Kindslehner, Angelika; Bockstahler, Barbara A; Dupré, Gilles P

2017-10-01

To compare design features and mechanical properties of 13 commercially available Veress needles (VN). In vitro biomechanical study. Veress needles from 9 manufacturers (6 reusable, 6 disposable, and 1 with a reusable stylet combined with a disposable cannula) were included in the study. Veress needles are designed with a spring-loaded stylet to protect the tip of the cannula following insertion into the abdomen. Stylet forces were measured with a scale in a test jig by moving the stylet in 0.5 mm steps into the hollow cannula. Forces and spring rates were derived from force-displacement plots. Mass, mechanical dimensions, and the bevel angle and geometry were assessed. Differences between VN models were analyzed with a univariate analysis of variance. Results are reported as mean ± SD or median (range). Physical and mechanical parameters differed between models. The exposed stylet length was 3.5 mm (2-7). Three bevel geometries (bias, lancet type, and back-cut) with angles between 20° and 40° were identified. Reusable VN weigh more (24.9 ± 2.2 g) than disposable designs (6.0 ± 2.3 g). The mean values for the spring rate and the residual stylet force were 0.23 ± 0.08 Nmm -1 and 0.94 ± 0.28 N, respectively. The mean force required to move the stylet to the cannula tip was 1.81 ± 0.29 N and 2.77 ± 0.54 N to move to the proximal end of the bevel. Commercially available VN use diverse bevel geometries and have different mechanical characteristics. Studies investigating laparoscopic entry complications should explicitly report the type of VN model used. © 2017 The American College of Veterinary Surgeons.

Dry needling: a literature review with implications for clinical practice guidelines1

PubMed Central

Dunning, James; Butts, Raymond; Mourad, Firas; Young, Ian; Flannagan, Sean; Perreault, Thomas

2014-01-01

Background: Wet needling uses hollow-bore needles to deliver corticosteroids, anesthetics, sclerosants, botulinum toxins, or other agents. In contrast, dry needling requires the insertion of thin monofilament needles, as used in the practice of acupuncture, without the use of injectate into muscles, ligaments, tendons, subcutaneous fascia, and scar tissue. Dry needles may also be inserted in the vicinity of peripheral nerves and/or neurovascular bundles in order to manage a variety of neuromusculoskeletal pain syndromes. Nevertheless, some position statements by several US State Boards of Physical Therapy have narrowly defined dry needling as an ‘intramuscular’ procedure involving the isolated treatment of ‘myofascial trigger points’ (MTrPs). Objectives: To operationalize an appropriate definition for dry needling based on the existing literature and to further investigate the optimal frequency, duration, and intensity of dry needling for both spinal and extremity neuromusculoskeletal conditions. Major findings: According to recent findings in the literature, the needle tip touches, taps, or pricks tiny nerve endings or neural tissue (i.e. ‘sensitive loci’ or ‘nociceptors’) when it is inserted into a MTrP. To date, there is a paucity of high-quality evidence to underpin the use of direct dry needling into MTrPs for the purpose of short and long-term pain and disability reduction in patients with musculoskeletal pain syndromes. Furthermore, there is a lack of robust evidence validating the clinical diagnostic criteria for trigger point identification or diagnosis. High-quality studies have also demonstrated that manual examination for the identification and localization of a trigger point is neither valid nor reliable between-examiners. Conclusions: Several studies have demonstrated immediate or short-term improvements in pain and/or disability by targeting trigger points (TrPs) using in-and-out techniques such as ‘pistoning’ or ‘sparrow pecking’; however, to date, no high-quality, long-term trials supporting in-and-out needling techniques at exclusively muscular TrPs exist, and the practice should therefore be questioned. The insertion of dry needles into asymptomatic body areas proximal and/or distal to the primary source of pain is supported by the myofascial pain syndrome literature. Physical therapists should not ignore the findings of the Western or biomedical ‘acupuncture’ literature that have used the very same ‘dry needles’ to treat patients with a variety of neuromusculoskeletal conditions in numerous, large scale randomized controlled trials. Although the optimal frequency, duration, and intensity of dry needling has yet to be determined for many neuromusculoskeletal conditions, the vast majority of dry needling randomized controlled trials have manually stimulated the needles and left them in situ for between 10 and 30 minute durations. Position statements and clinical practice guidelines for dry needling should be based on the best available literature, not a single paradigm or school of thought; therefore, physical therapy associations and state boards of physical therapy should consider broadening the definition of dry needling to encompass the stimulation of neural, muscular, and connective tissues, not just ‘TrPs’. PMID:25143704

Design and evaluation of an intraocular B-scan OCT-guided 36-gauge needle

NASA Astrophysics Data System (ADS)

Shen, Jin H.; Joos, Karen M.

2015-03-01

Optical coherence tomography imaging is widely used in ophthalmology and optometry clinics for diagnosing retinal disorders. External microscope-mounted OCT operating room systems have imaged retinal changes immediately following surgical manipulations. However, the goal is to image critical surgical maneuvers in real time. External microscope-mounted OCT systems have some limitations with problems tracking constantly moving intraocular surgical instruments, and formation of absolute shadows by the metallic surgical instruments upon the underlying tissues of interest. An intraocular OCT-imaging probe was developed to resolve these problems. A disposable 25-gauge probe tip extended beyond the handpiece, with a 36-gauge needle welded to a disposable tip with its end extending an additional 3.5 mm. A sealed 0.35 mm diameter GRIN lens protected the fiber scanner and focused the scanning beam at a 3 to 4 mm distance. The OCT engine was a very high-resolution spectral-domain optical coherence tomography (SDOCT) system (870 nm, Bioptigen, Inc. Durham, NC) which produced 2000 A-scan lines per B-scan image at a frequency of 5 Hz with the fiber optic oscillations matched to this frequency. Real-time imaging of the needle tip as it touched infrared paper was performed. The B-scan OCT-needle was capable of real-time performance and imaging of the phantom material. In the future, the B-scan OCT-guided needle will be used to perform sub-retinal injections.

Influence of hearing of 22 G Whitacre and 22 G Quincke needles.

PubMed

Sundberg, A; Wang, L P; Fog, J

1992-11-01

Audiograms were performed pre-operatively and 2 days postoperatively in 48 patients given spinal anaesthesia for transurethral resection of the prostate. Hearing levels were examined at 1000 Hz and below. Either 22 G standard design (Quincke) needles (n = 25) or 22 G pencil-point design (Whitacre) needles (n = 23) were used. Hearing loss of 10 dB or more at two or more frequencies were observed in six of 25 patients in the Quincke group and in two of 23 patients in the Whitacre group. The mean hearing level was more reduced in the Quincke group. The shape of the tip of the spinal needle seems to be of some importance to the effects on hearing level that may occur after spinal anaesthesia.

The use of the 25 Sprotte needle markedly reduces post-dural puncture headache in routine neurological practice.

PubMed

Bertolotto, Antonio; Malentacchi, Maria; Capobianco, Marco; di Sapio, Alessia; Malucchi, Simona; Motuzova, Yana; Pulizzi, Annalisa; Berchialla, Paola; Sperli, Francesca

2016-02-01

The objectives of this article are to test the feasibility of lumbar puncture (LP) using 25-gauge (G) needles in daily neurological practice and to compare the risk of post-dural puncture headache (PDPH) with four types of needles. In a prospective rater-blind study, pros and cons of four different LP needles, the 20G Quincke (20Q), 22G Sprotte (22S), 25G Whitacre (25W) and 25G Sprotte (25S), were evaluated in 394 LPs performed by seven neurologists. The neurologist performing the LP recorded the type and size of needle, intensity of pain, safety, time of the procedure and failure or success. Between five and 15 days later another neurologist, blind to the type of needle used, completed an ad-hoc questionnaire for PDPH. PDPH developed in 35.9% patients when using a 20Q needle, and in 12.9%, 6.8% and 1.6%, respectively, when using a 22S, 25W or 25S needle. The difference in incidence of PDPH following LP performed with the 20Q needle and the 25S or 22S was statistically significant (p < 0.001 and p = 0.008, respectively) and it approached significance when comparing the 25S and 25W (p = 0.06). As 25W and 25S needles need CSF aspiration, LP requires more time and skill. Pain caused by LP was similar with the four needles. The use of the 25S needle in diagnostic LP reduces the frequency and severity of PDPH. © International Headache Society 2015.

A flammability study of thin plastic film materials

NASA Technical Reports Server (NTRS)

Skinner, S. Ballou

1990-01-01

The Materials Science Laboratory at the Kennedy Space Center presently conducts flammability tests on thin plastic film materials by using a small needle rake method. Flammability data from twenty-two thin plastic film materials were obtained and cross-checked by using three different testing methods: (1) the presently used small needle rake; (2) the newly developed large needle rake; and (3) the previously used frame. In order to better discern the melting-burning phenomenon of thin plastic film material, five additional specific experiments were performed. These experiments determined the following: (1) the heat sink effect of each testing method; (2) the effect of the burn angle on the burn length or melting/shrinkage length; (3) the temperature profile above the ignition source; (4) the melting point and the fire point of each material; and (5) the melting/burning profile of each material via infrared (IR) imaging. The results of these experimentations are presented.

Shock Waves Mitigation at Blunt Bodies Using Needles and Shells Against a Supersonic Flow

NASA Technical Reports Server (NTRS)

Gilinsky, M.; Blankson, I. M.; Sakharov, V. I.; Shvets, A. I.

2004-01-01

The paper contains some experimental and numerical simulation test results on cylindrical blunt body drag reduction using thin spikes or shell mounted in front of a body against a supersonic flow. Experimental tests were conducted using the Aeromechanics and Gas Dynamics Laboratory facilities at the Institute of Mechanics of Moscow State University (IMMSU). Numerical simulations utilizing NASA and IM/MSU codes were conducted at the Hampton University Fluid Mechanics and Acoustics Laboratory. The main purpose of this research is to examine the efficiency of application of multiple spikes for drag reduction and flow stability at the front of a blunt body in different flight conditions, i.e. Mach number, angle of attack, etc. The principal conclusions of these test results are: multiple spike/needle application leads to decrease of drag reduction benefits by comparison with the case of one central mounted needle at the front of a blunt body, but increase lift benefits.

[Design of warm-acupuncture technique training evaluation device].

PubMed

Gao, Ming; Xu, Gang; Yang, Huayuan; Liu, Tangyi; Tang, Wenchao

2017-01-12

To design a warm-acupuncture teaching instrument to train and evaluate its manipulation. We refer to the principle and technical operation characteristics of traditional warm-acupuncture, as well as the mechanical design and single-chip microcomputer technology. The device is consisted of device noumenon, universal acupoints simulator, vibration reset system and circuit control system, including frame, platform framework, the swing framework, universal acupoints simulator, vibration reset outfit, operation time circuit, acupuncture sensation display, and vibration control circuit, etc. It can be used to train needle inserting with different angles and moxa rubbing and loading. It displays whether a needle point meets the location required. We determine whether the moxa group on a needle handle is easy to fall off through vibration test, and operation time is showed. The device can objectively help warm-acupuncture training and evaluation so as to promote its clinical standardization manipulation.

A Multicenter comparative trial of a novel EUS-guided core biopsy needle (SharkCore™) with the 22-gauge needle in patients with solid pancreatic mass lesions

PubMed Central

Naveed, Mariam; Siddiqui, Ali A.; Kowalski, Thomas E.; Loren, David E.; Khalid, Ammara; Soomro, Ayesha; Mazhar, Syed M.; Yoo, Joseph; Hasan, Raza; Yalamanchili, Silpa; Tarangelo, Nicholas; Taylor, Linda J.; Adler, Douglas G.

2018-01-01

Background and Objectives: The ability to obtain adequate tissue of solid pancreatic lesions by EUS-guided remains a challenge. The aim of this study was to compare the performance characteristics and safety of EUS-FNA for evaluating solid pancreatic lesions using the standard 22-gauge needle versus a novel EUS biopsy needle. Methods: This was a multicenter retrospective study of EUS-guided sampling of solid pancreatic lesions between 2009 and 2015. Patients underwent EUS-guided sampling with a 22-gauge SharkCore (SC) needle or a standard 22-gauge FNA needle. Technical success, performance characteristics of EUS-FNA, the number of needle passes required to obtain a diagnosis, diagnostic accuracy, and complications were compared. Results: A total of 1088 patients (mean age = 66 years; 49% female) with pancreatic masses underwent EUS-guided sampling with a 22-gauge SC needle (n = 115) or a standard 22-gauge FNA needle (n = 973). Technical success was 100%. The frequency of obtaining an adequate cytology by EUS-FNA was similar when using the SC and the standard needle (94.1% vs. 92.7%, respectively). The sensitivity, specificity, and diagnostic accuracy of EUS-FNA for tissue diagnosis were not significantly different between two needles. Adequate sample collection leading to a definite diagnosis was achieved by the 1st, 2nd, and 3rd pass in 73%, 92%, and 98% of procedures using the SC needle and 20%, 37%, and 94% procedures using the standard needle (P < 0.001), respectively. The median number of passes to obtain a tissue diagnosis using the SC needle was significantly less as compared to the standard needle (1 and 3, respectively; P < 0.001). Conclusions: The EUS SC biopsy needle is safe and technically feasible for EUS-FNA of solid pancreatic mass lesions. Preliminary results suggest that the SC needle has a diagnostic yield similar to the standard EUS needle and significantly reduces the number of needle passes required to obtain a tissue diagnosis. PMID:29451167

Comparison of 25-gauge, Quincke and Whitacre needles for postdural puncture headache in obstetric patients.

PubMed

Bano, Fauzia; Haider, Saeeda; Aftab, Sadqa; Sultan, S Tipu

2004-11-01

To compare the frequency of postdural puncture headache (PDPH) and failure rate of spinal anesthesia using 25-gauge Quincke and 25-gauge Whitacre needles in obstetric patients. Single blinded, interventional experimental study. This study was conducted at the Department of Anesthesiology, Pain Management and Surgical Intensive Care Unit, Dow University of Health Sciences and Civil Hospital, Karachi from November 1, 2003-April 15, 2004. One hundred females, aged 18-35 years, ASA physical status I and II, with singleton pregnancy undergoing elective or emergency cesarean section under spinal anesthesia were randomly allocated to receive spinal anesthesia either by using 25-gauge Quincke or 25-gauge Whitacre needles. Patients were followed for 3 days postoperatively. Headache, its relation with posture, onset, duration, severity and response to the treatment were recorded. Compared with the Whitacre group, frequency of postdural puncture headache was significantly higher in Quincke group (*p=0.015), while the overall occurrence of non-postdural puncture headache (NPDPH) did not differ significantly between two groups (p=0.736). Most of PDPH developed on 2nd postoperative day, were mild in nature and resolved within 48 hours of their onset. There was no significant difference in the failure rate of spinal anesthesia in both groups (p=0.149). It is suggested that use of 25-gauge Whitacre needle reduces the frequency of PDPH without increasing the failure rate of spinal anesthesia in obstetric patients.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirata, Masaaki, E-mail: masaaki314@gmail.com; Watanabe, Ryouhei; Koyano, Yasuhiro

PurposeTo demonstrate the use of “Smart Puncture,” a smartphone application to assist conventional CT-guided puncture without CT fluoroscopy, and to describe the advantages of this application.Materials and MethodsA puncture guideline is displayed by entering the angle into the application. Regardless of the angle at which the device is being held, the motion sensor ensures that the guideline is displayed at the appropriate angle with respect to gravity. The angle of the smartphone’s liquid crystal display (LCD) is also detected, preventing needle deflection from the CT slice image. Physicians can perform the puncture procedure by advancing the needle using the guidelinemore » while the smartphone is placed adjacent to the patient. In an experimental puncture test using a sponge as a target, the target was punctured at 30°, 50°, and 70° when the device was tilted to 0°, 15°, 30°, and 45°, respectively. The punctured target was then imaged with a CT scan, and the puncture error was measured.ResultsThe mean puncture error in the plane parallel to the LCD was less than 2°, irrespective of device tilt. The mean puncture error in the sagittal plane was less than 3° with no device tilt. However, the mean puncture error tended to increase when the tilt was increased.ConclusionThis application can transform a smartphone into a valuable tool that is capable of objectively and accurately assisting CT-guided puncture procedures.« less

The appropriateness of the length of insulin needles based on determination of skin and subcutaneous fat thickness in the abdomen and upper arm in patients with type 2 diabetes.

PubMed

Sim, Kang Hee; Hwang, Moon Sook; Kim, Sun Young; Lee, Hye Mi; Chang, Ji Yeun; Lee, Moon Kyu

2014-04-01

Longer needle and complicated insulin injection technique such as injecting at a 45-degree angle and making skinfolds may decrease patient compliance to insulin injection therapy. In this light, shorter insulin needles have been recently developed. However, it is necessary to ascertain that such shorter needles are appropriate for Korean patients with diabetes as well. First, the diverse demographic and diabetic features of 156 Korean adults with diabetes were collected by a questionnaire and a device unit of body fat measurement. The skin and subcutaneous fat thicknesses of each subject were measured by Ultrasound device with a 7- to 12-MHz probe. Data were analyzed using analysis of variance and multiple linear regression. The mean skin thickness was 2.29±0.37 mm in the abdomen and 2.00±0.34 mm in the upper arms, and the mean subcutaneous fat thickness was to 10.15±6.54 mm in the abdomen and 5.50±2.68 mm in the upper arms. Our analysis showed that the factors affecting the skin thickness of the abdomen and upper arms were gender and body mass index (BMI), whereas the factors influencing the subcutaneous fat thickness in the abdomen were gender and BMI, and the factors influencing the subcutaneous fat thickness in the upper arms were gender, BMI, and age. Insulin fluids may not appear to be intradermally injected into the abdomen and upper arms at any needle lengths. The risk of intramuscular injection is likely to increase with longer insulin needles and lower BMI. It is recommended to fully inform the patients about the lengths of needles for insulin injections. As for the recommended needle length, the findings of this study indicate that needles as short as 4 mm are sufficient to deliver insulin for Korean patients with diabetes.

The Appropriateness of the Length of Insulin Needles Based on Determination of Skin and Subcutaneous Fat Thickness in the Abdomen and Upper Arm in Patients with Type 2 Diabetes

PubMed Central

Sim, Kang Hee; Kim, Sun Young; Lee, Hye Mi; Chang, Ji Yeun; Lee, Moon Kyu

2014-01-01

Background Longer needle and complicated insulin injection technique such as injecting at a 45-degree angle and making skinfolds may decrease patient compliance to insulin injection therapy. In this light, shorter insulin needles have been recently developed. However, it is necessary to ascertain that such shorter needles are appropriate for Korean patients with diabetes as well. Methods First, the diverse demographic and diabetic features of 156 Korean adults with diabetes were collected by a questionnaire and a device unit of body fat measurement. The skin and subcutaneous fat thicknesses of each subject were measured by Ultrasound device with a 7- to 12-MHz probe. Data were analyzed using analysis of variance and multiple linear regression. Results The mean skin thickness was 2.29±0.37 mm in the abdomen and 2.00±0.34 mm in the upper arms, and the mean subcutaneous fat thickness was to 10.15±6.54 mm in the abdomen and 5.50±2.68 mm in the upper arms. Our analysis showed that the factors affecting the skin thickness of the abdomen and upper arms were gender and body mass index (BMI), whereas the factors influencing the subcutaneous fat thickness in the abdomen were gender and BMI, and the factors influencing the subcutaneous fat thickness in the upper arms were gender, BMI, and age. Insulin fluids may not appear to be intradermally injected into the abdomen and upper arms at any needle lengths. The risk of intramuscular injection is likely to increase with longer insulin needles and lower BMI. Conclusion It is recommended to fully inform the patients about the lengths of needles for insulin injections. As for the recommended needle length, the findings of this study indicate that needles as short as 4 mm are sufficient to deliver insulin for Korean patients with diabetes. PMID:24851206

Electrohydrodynamic deposition of polymeric droplets under low-frequency pulsation.

PubMed

Xu, Lei; Wang, Xiang; Lei, Tingping; Sun, Daoheng; Lin, Liwei

2011-05-17

Circularly shaped polymeric droplets with diameter of about 20 μm have been intermittently ejected and deposited in an orderly manner on a collector from a syringe needle by means of near-field, electrohydrodynamic reactions using pulsating voltages at around 2.25 kV. The needle has an inner diameter of 100 μm and was placed 1 mm above a silicon conductor substrate to have location control for droplet depositions. Under low-frequency operation of less than 100 Hz, the deposition frequency of droplets, f(dep), has been observed to be equal to the frequency of the applied driving voltage divided by an integer, N, as small as 1. Furthermore, the diameter of the deposited droplets has been found to be linearly dependent on (Q/f(dep))(1/3), where Q is the polymer solution supply rate at around 30 nL/s. These experimentally observed droplet ejection rules under low-frequency pulsation provide useful design guidelines for controllable deposition of polymer droplets in various potential applications, including electrohydrodynamic printing.

Experimental and computational analysis of sound absorption behavior in needled nonwovens

NASA Astrophysics Data System (ADS)

Soltani, Parham; Azimian, Mehdi; Wiegmann, Andreas; Zarrebini, Mohammad

2018-07-01

In this paper application of X-ray micro-computed tomography (μCT) together with fluid simulation techniques to predict sound absorption characteristics of needled nonwovens is discussed. Melt-spun polypropylene fibers of different fineness were made on an industrial scale compact melt spinning line. A conventional batt forming-needling line was used to prepare the needled samples. The normal incidence sound absorption coefficients were measured using impedance tube method. Realistic 3D images of samples at micron-level spatial resolution were obtained using μCT. Morphology of fabrics was characterized in terms of porosity, fiber diameter distribution, fiber curliness and pore size distribution from high-resolution realistic 3D images using GeoDict software. In order to calculate permeability and flow resistivity of media, fluid flow was simulated by numerically solving incompressible laminar Newtonian flow through the 3D pore space of realistic structures. Based on the flow resistivity, the frequency-dependent acoustic absorption coefficient of the needled nonwovens was predicted using the empirical model of Delany and Bazley (1970) and its associated modified models. The results were compared and validated with the corresponding experimental results. Based on morphological analysis, it was concluded that for a given weight per unit area, finer fibers yield to presence of higher number of fibers in the samples. This results in formation of smaller and more tortuous pores, which in turn leads to increase in flow resistivity of media. It was established that, among the empirical models, Mechel modification to Delany and Bazley model had superior predictive ability when compared to that of the original Delany and Bazley model at frequency range of 100-5000 Hz and is well suited to polypropylene needled nonwovens.

Stereo-photography of streamers in air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nijdam, S.; Moerman, J. S.; Briels, T. M. P.

2008-03-10

Standard photographs of streamer discharges show a two-dimensional projection. Here, we present stereophotographic images that resolve their three-dimensional structure. We describe the stereoscopic setup and evaluation, and we present results for positive streamer discharges in air at 0.2-1 bar in a point-plane geometry with a gap distance of 14 cm and a voltage pulse of 47 kV. In this case, an approximately Gaussian distribution of branching angles of 43 deg. {+-}12 deg. is found; these angles do not significantly depend on the distance from the needle or on the gas pressure.

[Electron microscopy of the lesions produced in the human dura mater by Quincke beveled and Whitacre needles].

PubMed

Reina, M A; López-García, A; de Andrés-Ibáñez, J A; Dittmann, M; Cascales, M R; del Caño, M C; Daneri, J; Zambrano, O

1997-02-01

Comparisons of Quincke needles and non traumatic "pencil point" needles in recent years have reported lower rates of post dural puncture headache using the later type. Our new understanding of the morphology of the human dura mater motivated us to study dural lesions caused by the Whitacre 25 G and Quincke 26 G needles, using scanning electron microscopy with the aim of determining whether there is an anatomic basis for the different outcomes. The dura mater from three fresh cadavers of individuals aged 65, 70 and 72 years were punctured 40 times at an angle of 90 degrees each time. The Whitacre 25 G needle was used for 20 punctures and the Quincke 26 G needle was used for the other 20. Half the punctures were performed with the bevel in the parallel alignment and the other half with the bevel perpendicular to the spinal column. Fifteen min after causing the punctures, specimens were fixed in solutions of glutaraldehyde phosphate buffer and dehydrated in acetone. After critical point removal of the acetone, after the specimens were treated with carbon and metallized with gold. The lesions were examined externally and internally and expressed as the ratio of area of lesion to diameter of the needle that had caused them. Whitacre needle: each lesion consisted in the superimposition of multiple damaged layers that started to close individually. After 15 min the outermost layers were 90% closed and the innermost ones had closed entirely. Layers in the arachnoid surface of the dura mater had closed from 86 to 88%, while deeper layers in the thick part had closed 97 to 98%. Quincke needle: lesions were V-shaped or half-moon shaped, much like the opening formed by a can opener, on both the external and internal surfaces. Alignment of the bevel of the needle parallel to the spinal column did not lead to a different shape of puncture. After 15 min the lesions had closed 94 to 95% on the epidural surface and 95 to 96% on the arachnoid side, a difference attributable to the retraction of the arachnoid layers over the spinal column. Non traumatic beveled dural needles, termed "pencil point needles", only partially separate dural fibers, and lesions caused by these needles develop in a more complex way. The Quincke 26G needle produced a puncture that is morphologically different from that caused by the Whitacre 25G needle, although lesions produced by both types close more than 94% after 15 min. We believe the size of the lesion caused by these needles does not explain the difference in post dural puncture headache due to loss of spinal fluid.

[Comparison of different moxibustion techniques in clinical treatment of diseases based on data mining].

PubMed

Zhu, Xue-liang; Tan, Zhan-na; Li, Bo-ying; Wang, Jian-ling; Shi, Jing; Sun, Yan-hui; Li, Xiao- feng; Xu, Jing; Zhang, Xuan-ping; Zhang, Xin; Du, Yu-zhu; Jia, Chun-shieng

2014-09-01

To explore the specific efficacy of different moxibustion techniques in treatment of common diseases and clinical indications, and compare the specificity in clinical indications and efficacy among different moxibustion techniques so as to guide clinical practice better. The modern computerization and data mining technology were adopted to set up moxibustion literature database. The relevant literature of moxibustion techniques in recent 60 years were collected, screened, examined, extracted and analyzed statistically so as to explore the advantages of different moxibustion techniques in clinical treatment. (1) Of 2,516 literature, moxa stick, moxe cone and moxa device were used in the highest frequency in internal medicine department, for 730 times, 278 times and 102 times respectively. The warm needling technique was used in the highest frequency, for 70 times in the surgical department. (2) In the dermatology department, the curative rate with moxa cone was the highest, 75%. In the ear-nose-throat department, the warm needing technique and moxa device achieved the highest curative rate, 49% for both of them. In the internal medicine department and surgical department, the curative rate of warm needling technique was 53% and 58% respectively. In the gynecology department, the curative rate of moxa device was the highest, 59%. In the pediatrics department, the curative rate of moxa cone was the highest, 80%. (3) The numbers of priority disorders, frequency ≥20 times: 24 kinds of disease for moxa stick, five kinds of disease for moxa cone, 2 kinds of disease for warm needling technqiue and one disorder for moxa device. Facial paralysis, diarrhea, lumbar and leg pain and elbow and knee swelling pain were of the highest priority, treated with these 4 moxibustion techniques, with a certain of literature research values. (4) The warm needling technique achieved the better efficacy on elbow and knee swelling pain, lumbar and leg pain and diarrhea compared with the other three techniques and the curative rate was higher. The moxa device tecnique achieved the higher curative rate for facial paralysis compared with the other three techniques. Through the comparison of application frequency, curative rate, clinical application frequency in disorders and the efficacy of priority disorders in the treatment with different moxibustion techniques, it is found that moxa stick, moxa cone and moxa device are simple in manipulation, safe and effective. Hence, they can be extensively used in the treatment of common disorders in every department in clinic. The warm needling technique acts on the body by the co-work of needling and warming stimulation of mugwort. It achieves the particular effect on the disorders with complicated etiologies compared with the other three techniques. It can be chosen in priority for the disorders caused by blockage in meridian and collateral and stagnation of qi and blood.

Social context of needle selling in Baltimore, Maryland.

PubMed

Latkin, Carl A; Davey, Melissa A; Hua, Wei

2006-01-01

Although much of the debate surrounding the distribution of sterile syringes to injection drug users (IDUs) has focused on needle exchange programs (NEPs), IDUs acquire their syringes from three major sources: NEPs, pharmacies, and secondary exchangers or needle sellers. The purpose of the present study is to examine types and frequencies of social interactions among drug injectors who sell needles, most of which come from NEPs, compared with individuals who do not sell needles. Specifically, we compared engagement in drug-related behaviors, roles in the drug economy, and social network membership. Data were collected as part of the SHIELD study, an HIV prevention intervention targeted at drug users and their social networks (n=910) from February 2001 through September 2003 in Baltimore, Maryland (USA). In this sample, 56 participants reported selling needles. Needle sellers had higher levels of engagement in drug-related social interactions, including using drugs with others, giving or receiving drugs from others, and buying drugs with other users. Participants who sold needles had a significantly higher number of roles in the drug economy. Also, they had more social network members who were injectors, with whom they talked about risky drug behaviors, gave needles to, and shared cookers and bleach with. Compared with nonselling injectors, needle sellers engage in HIV risk-related behaviors, such as injecting daily and sharing injection equipment, more frequently. The study's findings may be useful to determine whether secondary exchangers should be targeted for HIV prevention activities both to reduce their own risk and to diffuse risk reduction information throughout the drug using community.

Simulation and training of ultrasound supported anaesthesia: a low-cost approach

NASA Astrophysics Data System (ADS)

Schaaf, T.; Lamontain, M.; Hilpert, J.; Schilling, F.; Tolxdorff, T.

2010-03-01

The use of ultrasound imaging technology during techniques of peripheral nerve blockade offers several clinical benefits. Here we report on a new method to educate residents in ultrasound-guided regional anesthesia. The daily challenge for the anesthesiologists is the 3D angle-depending handling of the stimulation needle and the ultrasound probe while watching the 2D ultrasound image on the monitor. Purpose: Our approach describes how a computer-aided simulation and training set for ultrasound-guided regional anesthesia could be built based on wireless low-cost devices and an interactive simulation of a 2D ultrasound image. For training purposes the injection needle and the ultrasound probe are replaced by wireless Bluetooth-connected 3D tracking devices, which are embedded in WII-mote controllers (Nintendo-Brand). In correlation to the tracked 3D positions of the needle and transducer models the visibility and position of the needle should be simulated in the 2D generated ultrasound image. Conclusion: In future, this tracking and visualization software module could be integrated in a more complex training set, where complex injection paths could be trained based on a 3D segmented model and the training results could be part of a curricular e-learning module.

Ultrasound-guided three-dimensional needle steering in biological tissue with curved surfaces

PubMed Central

Abayazid, Momen; Moreira, Pedro; Shahriari, Navid; Patil, Sachin; Alterovitz, Ron; Misra, Sarthak

2015-01-01

In this paper, we present a system capable of automatically steering a bevel-tipped flexible needle under ultrasound guidance toward a physical target while avoiding a physical obstacle embedded in gelatin phantoms and biological tissue with curved surfaces. An ultrasound pre-operative scan is performed for three-dimensional (3D) target localization and shape reconstruction. A controller based on implicit force control is developed to align the transducer with curved surfaces to assure the maximum contact area, and thus obtain an image of sufficient quality. We experimentally investigate the effect of needle insertion system parameters such as insertion speed, needle diameter and bevel angle on target motion to adjust the parameters that minimize the target motion during insertion. A fast sampling-based path planner is used to compute and periodically update a feasible path to the target that avoids obstacles. We present experimental results for target reconstruction and needle insertion procedures in gelatin-based phantoms and biological tissue. Mean targeting errors of 1.46 ± 0.37 mm, 1.29 ± 0.29 mm and 1.82 ± 0.58 mm are obtained for phantoms with inclined, curved and combined (inclined and curved) surfaces, respectively, for insertion distance of 86–103 mm. The achieved targeting errors suggest that our approach is sufficient for targeting lesions of 3 mm radius that can be detected using clinical ultrasound imaging systems. PMID:25455165

Particle beam injector system and method

DOEpatents

Guethlein, Gary

2013-06-18

Methods and devices enable coupling of a charged particle beam to a radio frequency quadrupole accelerator. Coupling of the charged particle beam is accomplished, at least in-part, by relying on of sensitivity of the input phase space acceptance of the radio frequency quadrupole to the angle of the input charged particle beam. A first electric field across a beam deflector deflects the particle beam at an angle that is beyond the acceptance angle of the radio frequency quadrupole. By momentarily reversing or reducing the established electric field, a narrow portion of the charged particle beam is deflected at an angle within the acceptance angle of the radio frequency quadrupole. In another configuration, beam is directed at an angle within the acceptance angle of the radio frequency quadrupole by the first electric field and is deflected beyond the acceptance angle of the radio frequency quadrupole due to the second electric field.

Influence of temperature, needle gauge and injection rate on the size distribution, concentration and acoustic responses of ultrasound contrast agents at high frequency.

PubMed

Sun, Chao; Panagakou, Ioanna; Sboros, Vassilis; Butler, Mairead B; Kenwright, David; Thomson, Adrian J W; Moran, Carmel M

2016-08-01

This paper investigated the influence of needle gauge (19G and 27G), injection rate (0.85ml·min(-1), 3ml·min(-1)) and temperature (room temperature (RT) and body temperature (BT)) on the mean diameter, concentration, acoustic attenuation, contrast to tissue ratio (CTR) and normalised subharmonic intensity (NSI) of three ultrasound contrast agents (UCAs): Definity, SonoVue and MicroMarker (untargeted). A broadband substitution technique was used to acquire the acoustic properties over the frequency range 17-31MHz with a preclinical ultrasound scanner Vevo770 (Visualsonics, Canada). Significant differences (P<0.001-P<0.05) between typical in vitro setting (19G needle, 3ml·min(-1) at RT) and typical in vivo setting (27G needle, 0.85ml·min(-1) at BT) were found for SonoVue and MicroMarker. Moreover we found that the mean volume-based diameter and concentration of both SonoVue and Definity reduced significantly when changing from typical in vitro to in vivo experimental set-ups, while those for MicroMarker did not significantly change. From our limited measurements of Definity, we found no significant change in attenuation, CTR and NSI with needle gauge. For SonoVue, all the measured acoustic properties (attenuation, CTR and NSI) reduced significantly when changing from typical in vitro to in vivo experimental conditions, while for MicroMarker, only the NSI reduced, with attenuation and CTR increasing significantly. These differences suggest that changes in physical compression and temperature are likely to alter the shell structure of the UCAs resulting in measureable and significant changes in the physical and high frequency acoustical properties of the contrast agents under typical in vitro and preclinical in vivo experimental conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Electromagnetic wave scattering from some vegetation samples

NASA Technical Reports Server (NTRS)

Karam, Mostafa A.; Fung, Adrian K.; Antar, Yahia M.

1988-01-01

For an incident plane wave, the field inside a thin scatterer (disk and needle) is estimated by the generalized Rayleigh-Gans (GRG) approximation. This leads to a scattering amplitude tensor equal to that obtained via the Rayleigh approximation (dipole term) with a modifying function. For a finite-length cylinder the inner field is estimated by the corresponding field for the same cylinder of infinite lenght. The effects of different approaches in estimating the field inside the scatterer on the backscattering cross section are illustrated numerically for a circular disk, a needle, and a finite-length cylinder as a function of the wave number and the incidence angle. Finally, the modeling predictions are compared with measurements.

A population genetic model for high-elevation five-needle pines: Projecting population outcomes in the presence of white pine blister rust

Treesearch

A. W. Schoettle; J. G. Klutsch; M. F. Antolin; S. Field

2011-01-01

The slow growth and long generation time of the five-needle pines have historically enabled these trees to persist on the landscape for centuries, but without sufficient regeneration opportunities these same traits hinder the species' ability to adapt to novel stresses such as the non-native disease white pine blister rust (WPBR). Increasing the frequency of...

Localization of needle tip with color doppler during pericardiocentesis: In vitro validation and initial clinical application

NASA Technical Reports Server (NTRS)

Armstrong, G.; Cardon, L.; Vilkomerson, D.; Lipson, D.; Wong, J.; Rodriguez, L. L.; Thomas, J. D.; Griffin, B. P.

2001-01-01

This study evaluates a new device that uses color Doppler ultrasonography to enable real-time image guidance of the aspirating needle, which has not been possible until now. The ColorMark device (EchoCath Inc, Princeton, NJ) induces high-frequency, low-amplitude vibrations in the needle to enable localization with color Doppler. We studied this technique in 25 consecutive patients undergoing pericardiocentesis, and in vitro, in a urethane phantom with which the accuracy of color Doppler localization of the needle tip was compared with that obtained by direct measurement. Tip localization was excellent in vitro; errors axial to the ultrasound beam (velocity Doppler -0.13 +/- 0.90 mm, power Doppler -0.05 +/- 1.7 mm) were less than lateral errors (velocity -0.36 +/- 1.8 mm, power -0.02 +/- 2.8 mm). In 18 of 25 patients, the needle was identified and guided into the pericardial space with the ColorMark technique, and it allowed successful, uncomplicated drainage of fluid. Initial failures were the result of incorrect settings on the echocardiographic machine and inappropriate combinations of the needle puncture site and imaging window. This study demonstrates a novel color Doppler technique that is highly accurate at localizing a needle tip. The technique is feasible for guiding pericardiocentesis. Further clinical validation of this technique is required.

Head-mounted display augmented reality to guide pedicle screw placement utilizing computed tomography.

PubMed

Gibby, Jacob T; Swenson, Samuel A; Cvetko, Steve; Rao, Raj; Javan, Ramin

2018-06-22

Augmented reality has potential to enhance surgical navigation and visualization. We determined whether head-mounted display augmented reality (HMD-AR) with superimposed computed tomography (CT) data could allow the wearer to percutaneously guide pedicle screw placement in an opaque lumbar model with no real-time fluoroscopic guidance. CT imaging was obtained of a phantom composed of L1-L3 Sawbones vertebrae in opaque silicone. Preprocedural planning was performed by creating virtual trajectories of appropriate angle and depth for ideal approach into the pedicle, and these data were integrated into the Microsoft HoloLens using the Novarad OpenSight application allowing the user to view the virtual trajectory guides and CT images superimposed on the phantom in two and three dimensions. Spinal needles were inserted following the virtual trajectories to the point of contact with bone. Repeat CT revealed actual needle trajectory, allowing comparison with the ideal preprocedural paths. Registration of AR to phantom showed a roughly circular deviation with maximum average radius of 2.5 mm. Users took an average of 200 s to place a needle. Extrapolation of needle trajectory into the pedicle showed that of 36 needles placed, 35 (97%) would have remained within the pedicles. Needles placed approximated a mean distance of 4.69 mm in the mediolateral direction and 4.48 mm in the craniocaudal direction from pedicle bone edge. To our knowledge, this is the first peer-reviewed report and evaluation of HMD-AR with superimposed 3D guidance utilizing CT for spinal pedicle guide placement for the purpose of cannulation without the use of fluoroscopy.

Geographical and climatic limits of needle types of one- and two-needled pinyon pines

USGS Publications Warehouse

Cole, K.L.; Fisher, J.; Arundel, S.T.; Cannella, J.; Swift, S.

2008-01-01

Aim: The geographical extent and climatic tolerances of one- and two-needled pinyon pines (Pinus subsect. Cembroides) are the focus of questions in taxonomy, palaeoclimatology and modelling of future distributions. The identification of these pines, traditionally classified by one- versus two-needled fascicles, is complicated by populations with both one- and two-needled fascicles on the same tree, and the description of two more recently described one-needled varieties: the fallax-type and californiarum-type. Because previous studies have suggested correlations between needle anatomy and climate, including anatomical plasticity reflecting annual precipitation, we approached this study at the level of the anatomy of individual pine needles rather than species. Location: Western North America. Methods: We synthesized available and new data from field and herbarium collections of needles to compile maps of their current distributions across western North America. Annual frequencies of needle types were compared with local precipitation histories for some stands. Historical North American climates were modelled on a c. 1-km grid using monthly temperature and precipitation values. A geospatial model (ClimLim), which analyses the effect of climate-modulated physiological and ecosystem processes, was used to rank the importance of seasonal climate variables in limiting the distributions of anatomical needle types. Results: The pinyon needles were classified into four distinct types based upon the number of needles per fascicle, needle thickness and the number of stomatal rows and resin canals. The individual needles fit well into four categories of needle types, whereas some trees exhibit a mixture of two needle types. Trees from central Arizona containing a mixture of Pinus edulis and fallax-type needles increased their percentage of fallax-type needles following dry years. All four needle types occupy broader geographical regions with distinctive precipitation regimes. Pinus monophylla and californiarum-type needles occur in regions with high winter precipitation. Pinus edulis and fallax-type needles are found in regions with high monsoon precipitation. Areas supporting californiarum-type and fallax-type needle distributions are additionally characterized by a more extreme May-June drought. Main conclusions: These pinyon needle types seem to reflect the amount and seasonality of precipitation. The single needle fascicle characterizing the fallax type may be an adaptation to early summer or periodic drought, while the single needle of Pinus monophylla may be an adaptation to summer-autumn drought. Although the needles fit into four distinct categories, the parent trees are sometimes less easily classified, especially near their ancestral Pleistocene ranges in the Mojave and northern Sonoran deserts. The abundance of trees with both one- and two-needled fascicles in the zones between P. monophylla, P. edulis and fallax-type populations suggest that needle fascicle number is an unreliable characteristic for species classification. Disregarding needle fascicle number, the fallax-type needles are nearly identical to P. edulis, supporting Little's (1968) initial classification of these trees as P. edulis var. fallax, while the californiarum-type needles have a distinctive morphology supporting Bailey's (1987) classification of this tree as Pinus californiarum.

WE-DE-201-08: Multi-Source Rotating Shield Brachytherapy Apparatus for Prostate Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dadkhah, H; Wu, X; Kim, Y

Purpose: To introduce a novel multi-source rotating shield brachytherapy (RSBT) apparatus for the precise simultaneous angular and linear positioning of all partially-shielded 153Gd radiation sources in interstitial needles for treating prostate cancer. The mechanism is designed to lower the detrimental dose to healthy tissues, the urethra in particular, relative to conventional high-dose-rate brachytherapy (HDR-BT) techniques. Methods: Following needle implantation, the delivery system is docked to the patient template. Each needle is coupled to a multi-source afterloader catheter by a connector passing through a shaft. The shafts are rotated by translating a moving template between two stationary templates. Shaft walls asmore » well as moving template holes are threaded such that the resistive friction produced between the two parts exerts enough force on the shafts to bring about the rotation. Rotation of the shaft is then transmitted to the shielded source via several keys. Thus, shaft angular position is fully correlated with the position of the moving template. The catheter angles are simultaneously incremented throughout treatment as needed, and only a single 360° rotation of all catheters is needed for a full treatment. For each rotation angle, source depth in each needle is controlled by a multi-source afterloader, which is proposed as an array of belt-driven linear actuators, each of which drives a source wire. Results: Optimized treatment plans based on Monte Carlo dose calculations demonstrated RSBT with the proposed apparatus reduced urethral D{sub 1cc} below that of conventional HDR-BT by 35% for urethral dose gradient volume within 3 mm of the urethra surface. Treatment time to deliver 20 Gy with multi-source RSBT apparatus using nineteen 62.4 GBq {sup 153}Gd sources is 117 min. Conclusions: The proposed RSBT delivery apparatus in conjunction with multiple nitinol catheter-mounted platinum-shielded {sup 153}Gd sources enables a mechanically feasible urethra-sparing treatment technique for prostate cancer in a clinically reasonable timeframe.« less

Imaging of implant needles for real-time HDR-brachytherapy prostate treatment using biplane ultrasound transducers.

PubMed

Siebert, Frank-André; Hirt, Markus; Niehoff, Peter; Kovács, György

2009-08-01

Ultrasound imaging is becoming increasingly important in prostate brachytherapy. In high-dose-rate (HDR) real-time planning procedures the definition of the implant needles is often performed by transrectal ultrasound. This article describes absolute measurements of the visibility and accuracy of manual detection of implant needle tips and compares measurement results of different biplane ultrasound systems in transversal and longitudinal (i.e., sagittal) ultrasound modes. To obtain a fixed coordinate system and stable conditions the measurements were carried out in a water tank using a dedicated marker system. Needles were manually placed in the phantom until the observer decided by the real-time ultrasound image that the zero position was reached. A comparison of three different ultrasound systems yielded an offset between 0.8 and 3.1 mm for manual detection of the needle tip in ultrasound images by one observer. The direction of the offset was discovered to be in the proximal direction, i.e., the actual needle position was located more distally compared to the ultrasound-based definition. In the second part of the study, the ultrasound anisotropy of trocar implant needles is reported. It was shown that the integrated optical density in a region of interest around the needle tip changes with needle rotation. Three peaks were observed with a phase angle of 120 degrees. Peaks appear not only in transversal but also in longitudinal ultrasound images, with a phase shift of 60 degrees. The third section of this study shows results of observer dependent influences on needle tip detection in sagittal ultrasound images considering needle rotation. These experiments were carried out using the marker system in a water tank. The needle tip was placed exactly at the position z=0 mm. It was found that different users tend to differently interpret the same ultrasound images. The needle tip was manually detected five times in the ultrasound images by three experienced observers at positions (+/- standard deviation) -0.53 +/- 0.16, -0.16 +/- 0.14, and -0.30 +/- 0.16 mm using a gain of 15 dB. The minus sign indicates that the needle tips were detected more proximally than the actual position of the needle tip. When using a gain of -15 dB the mean values of two observers resulted in -0.62 +/- 0.08 and -0.51 +/- 0.12 mm. Additionally an alternative approach to the direct needle tip definition was investigated. Two observers detected the solid part of the needle tip in sagittal images. This solid part, often named as "dead space end," is the distance between the needle tip and the beginning of the hollow part of the implant needle. The dead space end is 6.2 mm for the investigated needle type. Two users found mean values of -6.70 +/- 0.16 and -7.00 +/- 0.06 mm, respectively, for 15 dB gain and -6.90 +/- 0.09 and -7.02 +/- 0.06 mm using the -15 dB gain setting. The results show that ultrasound-based needle tip definition in sagittal viewing mode is accurate. The inter- and intraobserver errors should, however, be taken into account. A lower gain setting of the ultrasound system reduces the intraobserver error.

Animal feasibility study of an innovated splash-needle for endoscopic submucosal dissection in the upper gastrointestinal tract.

PubMed

Fujishiro, Mitsuhiro; Sugita, Noriyuki

2013-01-01

The high frequency of complications accompanying endoscopic submucosal dissection (ESD) and its complex processes suggest that the process requires improvement. The objective of the present study was to investigate the feasibility of an innovated splash-needle for ESD. An animal feasibility study with a living pig was conducted. Six resections per portion (esophagus and upper, middle, and lower thirds of the stomach) in a total of 24 resections were carried out by using an original splash-needle or an innovated splash-needle. Major innovations were a thicker part in the middle of the knife and a metal plate on the tip of the sheath to obtain more coagulation ability. Injection solution in the submucosal layer was also changed due to possible influence on the outcomes. Main outcome measurements were entire procedure time, cutting speed, and frequency of bleeding during ESD. All the 24 resections were completed without complications. Among the obtained data, only mean cutting speeds were significantly influenced by location of the simulated lesion, which revealed that ESD at the upper third was significantly quicker than that at the lower third (P = 0.01), and ESD at the esophagus was significantly slower than that at the three parts of the stomach (P < 0.01). There was no significant difference between the different knives in each variable. The innovated splash-needle will be feasible for human use, although the safety and advantages in clinical settings must be elucidated by proper comparative studies with existing knives in humans. © 2012 The Authors. Digestive Endoscopy © 2012 Japan Gastroenterological Endoscopy Society.

Effects of pine needle extract on pacemaker currents in interstitial cells of Cajal from the murine small intestine.

PubMed

Cheong, Hyeonsook; Paudyal, Dilli Parasad; Jun, Jae Yeoul; Yeum, Cheol Ho; Yoon, Pyung Jin; Park, Chan Guk; Kim, Man Yoo; So, Insuk; Kim, Ki Whan; Choi, Seok

2005-10-31

Extracts of pine needles (Pinus densiflora Sieb. et Zucc.) have diverse physiological and pharmacological actions. In this study we show that pine needle extract alters pacemaker currents in interstitial cells of Cajal (ICC) by modulating ATP-sensitive K+ channels and that this effect is mediated by prostaglandins. In whole cell patches at 30 degrees , ICC generated spontaneous pacemaker potentials in the current clamp mode (I = 0), and inward currents (pacemaker currents) in the voltage clamp mode at a holding potential of -70 mV. Pine needle extract hyperpolarized the membrane potential, and in voltage clamp mode decreased both the frequency and amplitude of the pacemaker currents, and increased the resting currents in the outward direction. It also inhibited the pacemaker currents in a dose-dependent manner. Because the effects of pine needle extract on pacemaker currents were the same as those of pinacidil (an ATP-sensitive K+ channel opener) we tested the effect of glibenclamide (an ATP-sensitive K+ channels blocker) on ICC exposed to pine needle extract. The effects of pine needle extract on pacemaker currents were blocked by glibenclamide. To see whether production of prostaglandins (PGs) is involved in the inhibitory effect of pine needle extract on pacemaker currents, we tested the effects of naproxen, a non-selective cyclooxygenase (COX-1 and COX-2) inhibitor, and AH6809, a prostaglandin EP1 and EP2 receptor antagonist. Naproxen and AH6809 blocked the inhibitory effects of pine needle extract on ICC. These results indicate that pine needle extract inhibits the pacemaker currents of ICC by activating ATP-sensitive K+ channels via the production of PGs.

Combined frequency modulated atomic force microscopy and scanning tunneling microscopy detection for multi-tip scanning probe microscopy applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morawski, Ireneusz; Institute of Experimental Physics, University of Wrocław, pl. M. Borna 9, 50-204 Wrocław; Spiegelberg, Richard

A method which allows scanning tunneling microscopy (STM) tip biasing independent of the sample bias during frequency modulated atomic force microscopy (AFM) operation is presented. The AFM sensor is supplied by an electronic circuit combining both a frequency shift signal and a tunneling current signal by means of an inductive coupling. This solution enables a control of the tip potential independent of the sample potential. Individual tip biasing is specifically important in order to implement multi-tip STM/AFM applications. An extensional quartz sensor (needle sensor) with a conductive tip is applied to record simultaneously topography and conductivity of the sample. Themore » high resonance frequency of the needle sensor (1 MHz) allows scanning of a large area of the surface being investigated in a reasonably short time. A recipe for the amplitude calibration which is based only on the frequency shift signal and does not require the tip being in contact is presented. Additionally, we show spectral measurements of the mechanical vibration noise of the scanning system used in the investigations.« less

Dura-arachnoid lesions produced by 22 gauge Quincke spinal needles during a lumbar puncture

PubMed Central

Reina, M; Lopez, A; Badorrey, V; De Andres, J A; Martin, S

2004-01-01

Aims: The dural and arachnoid hole caused by lumbar puncture needles is a determining factor in triggering headaches. The aim of this study is to assess the dimensions and morphological features of the dura mater and arachnoids when they are punctured by a 22 gauge Quincke needle having its bevel either in the parallel or in the transverse position. Methods: Fifty punctures were made with 22 gauge Quincke needles in the dural sac of four fresh cadavers using an "in vitro" model especially designed for this purpose. The punctures were performed by needles with bevels parallel or perpendicular to the spinal axis and studied under scanning electron microscopy. Results: Thirty five of the 50 punctures done by Quincke needles (19 in the external surface and 16 in the internal) were used for evaluation. When the needle was inserted with its bevel parallel to the axis of the dural sac (17 of 35), the size of the dura-arachnoid lesion was 0.032 mm2 in the epidural surface and 0.037 mm2 in the subarachnoid surface of the dural sac. When the needle's bevel was perpendicular to the axis (18 of 35) the measurement of the lesion size was 0.042 mm2 for the external surface and 0.033 mm2 for the internal. There were no statistical significant differences between these results. Conclusions: It is believed that the reported lower frequency of postdural puncture headache when the needle is inserted parallel to the cord axis should be explained by some other factors besides the size of the dura-arachnoid injury. PMID:15146008

Dura-arachnoid lesions produced by 22 gauge Quincke spinal needles during a lumbar puncture.

PubMed

Reina, M A; López, A; Badorrey, V; De Andrés, J A; Martín, S

2004-06-01

The dural and arachnoid hole caused by lumbar puncture needles is a determining factor in triggering headaches. The aim of this study is to assess the dimensions and morphological features of the dura mater and arachnoids when they are punctured by a 22 gauge Quincke needle having its bevel either in the parallel or in the transverse position. Fifty punctures were made with 22 gauge Quincke needles in the dural sac of four fresh cadavers using an "in vitro" model especially designed for this purpose. The punctures were performed by needles with bevels parallel or perpendicular to the spinal axis and studied under scanning electron microscopy. Thirty five of the 50 punctures done by Quincke needles (19 in the external surface and 16 in the internal) were used for evaluation. When the needle was inserted with its bevel parallel to the axis of the dural sac (17 of 35), the size of the dura-arachnoid lesion was 0.032 mm(2) in the epidural surface and 0.037 mm(2) in the subarachnoid surface of the dural sac. When the needle's bevel was perpendicular to the axis (18 of 35) the measurement of the lesion size was 0.042 mm(2) for the external surface and 0.033 mm(2) for the internal. There were no statistical significant differences between these results. It is believed that the reported lower frequency of postdural puncture headache when the needle is inserted parallel to the cord axis should be explained by some other factors besides the size of the dura-arachnoid injury.

Fine fuel heating by radiant flux

Treesearch

David Frankman; Brent W. Webb; Bret W. Butler; Don J. Latham

2010-01-01

Experiments were conducted wherein wood shavings and Ponderosa pine needles in quiescent air were subjected to a steady radiation heat flux from a planar ceramic burner. The internal temperature of these particles was measured using fine diameter (0.076mm diameter) type K thermocouples. A narrow angle radiometer was used to determine the emissive power generated by the...

Development of a high frequency single-element ultrasound needle transducer for anesthesia delivery

NASA Astrophysics Data System (ADS)

Ameri, Golafsoun; Son, Jungik; Liang, Jingwei; Foster, F. Stuart; Ganapathy, Sugantha; Peters, Terry M.

2017-03-01

Epidural anesthesia is one of the most commonly used and yet challenging techniques employed for pain management and anesthesia delivery. The major complications of this procedure are due to accidental dural puncture, with an incidence of 1-3%, which could lead to both temporary and irreversible permanent neurological complications. Needle placement under ultrasound (US) guidance has received increasing interest for improving needle placement accuracy. However, poor needle visibility in US, difficulties in displaying relevant anatomical structure such as dura mater due to attenuation and bone shadowing, and image interpretation variability among users pose significant hurdles for any US guidance system. As a result, US guidance for epidural injections has not been widely adopted for everyday use for the performance of neuraxial blocks. The difficulties in localizing the ligamentum flavum and dura with respect to the needle tip can be addressed by integrating A-mode US, provided by a single-element transducer at the needle tip, into the B-mode US guidance system. We have taken the first steps towards providing such a guidance system. Our goal is to improve the safety of this procedure with minimal changes to the clinical workflow. This work presents the design and development of a 20 MHz single-element US transducer housed at the tip of a 19 G needle hypodermic tube, which can fit inside an epidural introducer needle. In addition, the results from initial transducer characterization tests and performance evaluation of the transducer in a euthanized porcine model are provided.

Comparison of electroacupuncture frequency-related effects on heart rate variability in healthy volunteers: a randomized clinical trial.

PubMed

Lee, Jong-Ho; Kim, Kyu-Hyeong; Hong, Jin-Woo; Lee, Won-Chul; Koo, Sungtae

2011-06-01

This study aimed to compare the effects of high frequency electroacupuncture (EA) and low-frequency EA on the autonomic nervous system by using a heart rate variability measuring device in normal individuals. Fourteen participants were recruited and each participated in the high-frequency and low-frequency sessions (crossover design). The order of sessions was randomized and the interval between the two sessions was over 2 weeks. Participants received needle insertion with 120-Hz stimulation during the high-frequency session (high-frequency EA group), and with 2-Hz stimulation during the low-frequency session (low-frequency EA group). Acupuncture needles were directly inserted perpendicularly to LI 4 and LI 11 acupoints followed by delivery of electric pulses to these points for 15 minutes. Heart rate variability was measured 5 minutes before and after EA stimulation by a heart rate variability measuring system. We found a significant increase in the standard deviation of the normal-to-normal interval in the high-frequency EA group, with no change in the low-frequency EA group. Both the high-frequency and low-frequency EA groups showed no significant differences in other parameters including high-frequency power, low-frequency power, and the ratio of low-frequency power to high-frequency power. Based on these findings, we concluded that high-frequency EA stimulation is more effective than low-frequency EA stimulation in increasing autonomic nervous activity and there is no difference between the two EA frequencies in enhancing sympathovagal balance. Copyright © 2011 Korean Pharmacopuncture Institute. Published by .. All rights reserved.

Optical and electrical characteristics of hollow-needle to plate atmospheric-pressure discharge in nitrogen

NASA Astrophysics Data System (ADS)

Simek, Milan; Schmidt, Jiri; Pekarek, Stanislav; Khun, Josef

2006-10-01

We have studied basic optical and electrical characteristics of the DC hollow needle to plate electrical discharge enhanced by the gas flow through the needle. Substantial advantage of this arrangement is that all gas supplied to the discharge passes through the discharge zone and therefore it is affected by plasma chemical processes. Depending on the energy dissipated between electrodes, we previously observed two basic discharge regimes: a) DC corona and b) DC corona superimposed with pulsed filamentary streamers [1]. In this work, we have analyzed radiation induced by filamentary streamers. In addition to nitrogen emissions driven by electron impact processes we have detected emission induced by specific energy transfer processes [2]. We have also determined mean repetition frequency of filamentary streamers (0.1-15 kHz) for the needle-to-plane gap and for the nitrogen flow through the needle ranging between 2-6 mm and 1-10 slm, respectively. [1] M. Simek and S.Pekarek, GEC 2005, Bul. Am. Phys. Soc. 50, 29, (2005) ; [2] M. Simek at al, Pure Appl. Chem. 78, 1213, (2006).

Predictors of pneumothorax after CT-guided transthoracic needle lung biopsy: the role of quantitative CT.

PubMed

Chami, H A; Faraj, W; Yehia, Z A; Badour, S A; Sawan, P; Rebeiz, K; Safa, R; Saade, C; Ghandour, B; Shamseddine, A; Mukherji, D; Haydar, A A

2015-12-01

To evaluate the association of quantitative computed tomography (CT) measures of emphysema with the occurrence of pneumothorax after CT-guided needle lung biopsy (NLB) accounting for other risk factors. One hundred and sixty-three CT-guided NLBs performed between 2008 and 2013 with available complete chest CT within 30 days were reviewed for the occurrence of post-procedure pneumothorax. Percent emphysema was determined quantitatively as the percentage of lung voxels below -950 HU on chest CT images using automated software. Multivariable regression was used to assess the association of percent emphysema volume with the occurrence of post-procedure pneumothorax. The association of percent emphysema volume with the pneumothorax size and need for chest tube placement after NLB was also explored. Percent emphysema was significantly associated with the incidence of post-NLB pneumothorax (OR=1.10 95% confidence interval: 1.01-1.15; p=0.03) adjusting for lower-lobe lesion location, needle path length, lesion size, number of passes, and pleural needle trajectory angle. Percent emphysema was not associated with the size of the pneumothorax, nor the need for chest tube placement after NLB. Percent emphysema determined quantitatively from chest CT is a significant predictor of post-NLB pneumothorax. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

The influence of tip shape on bending force during needle insertion

PubMed Central

van de Berg, Nick J.; de Jong, Tonke L.; van Gerwen, Dennis J.; Dankelman, Jenny; van den Dobbelsteen, John J.

2017-01-01

Steering of needles involves the planning and timely modifying of instrument-tissue force interactions to allow for controlled deflections during the insertion in tissue. In this work, the effect of tip shape on these forces was studied using 10 mm diameter needle tips. Six different tips were selected, including beveled and conical versions, with or without pre-bend or pre-curve. A six-degree-of-freedom force/torque sensor measured the loads during indentations in tissue simulants. The increased insertion (axial) and bending (radial) forces with insertion depth — the force-displacement slopes — were analyzed. Results showed that the ratio between radial and axial forces was not always proportional. This means that the tip load does not have a constant orientation, as is often assumed in mechanics-based steering models. For all tip types, the tip-load assumed a more radial orientation with increased axial load. This effect was larger for straight tips than for pre-bent or pre-curved tips. In addition, the force-displacement slopes were consistently higher for (1) increased tip angles, and for (2) beveled tips compared to conical tips. Needles with a bent or curved tip allow for an increased bending force and a decreased variability of the tip load vector orientation. PMID:28074939

Relationship Between Frequency and Deflection Angle in the DNA Prism

PubMed Central

Chen, Zhen; Dorfman, Kevin D.

2013-01-01

The DNA prism is a modification of the standard pulsed-field electrophoresis protocol to provide a continuous separation, where the DNA are deflected at an angle that depends on their molecular weight. The standard switchback model for the DNA prism predicts a monotonic increase in the deflection angle as a function of the frequency for switching the field until a plateau regime is reached. However, experiments indicate that the deflection angle achieves a maximum value before decaying to a size-independent value at high frequencies. Using Brownian dynamics simulations, we show that the maximum in the deflection angle is related to the reorientation time for the DNA and the decay in deflection angle at high frequencies is due to inadequate stretching. The generic features of the dependence of the deflection angle on molecular weight, switching frequency, and electric field strength explain a number of experimental phenomena. PMID:23410375

First Evaluation of the New Thin Convex Probe Endobronchial Ultrasound Scope: A Human Ex Vivo Lung Study.

PubMed

Patel, Priya; Wada, Hironobu; Hu, Hsin-Pei; Hirohashi, Kentaro; Kato, Tatsuya; Ujiie, Hideki; Ahn, Jin Young; Lee, Daiyoon; Geddie, William; Yasufuku, Kazuhiro

2017-04-01

Endobronchial ultrasonography (EBUS)-guided transbronchial needle aspiration allows for sampling of mediastinal lymph nodes. The external diameter, rigidity, and angulation of the convex probe EBUS renders limited accessibility. This study compares the accessibility and transbronchial needle aspiration capability of the prototype thin convex probe EBUS against the convex probe EBUS in human ex vivo lungs rejected for transplant. The prototype thin convex probe EBUS (BF-Y0055; Olympus, Tokyo, Japan) with a thinner tip (5.9 mm), greater upward angle (170 degrees), and decreased forward oblique direction of view (20 degrees) was compared with the current convex probe EBUS (6.9-mm tip, 120 degrees, and 35 degrees, respectively). Accessibility and transbronchial needle aspiration capability was assessed in ex vivo human lungs declined for lung transplant. The distance of maximum reach and sustainable endoscopic limit were measured. Transbronchial needle aspiration capability was assessed using the prototype 25G aspiration needle in segmental lymph nodes. In all evaluated lungs (n = 5), the thin convex probe EBUS demonstrated greater reach and a higher success rate, averaging 22.1 mm greater maximum reach and 10.3 mm further endoscopic visibility range than convex probe EBUS, and could assess selectively almost all segmental bronchi (98% right, 91% left), demonstrating nearly twice the accessibility as the convex probe EBUS (48% right, 47% left). The prototype successfully enabled cytologic assessment of subsegmental lymph nodes with adequate quality using the dedicated 25G aspiration needle. Thin convex probe EBUS has greater accessibility to peripheral airways in human lungs and is capable of sampling segmental lymph nodes using the aspiration needle. That will allow for more precise assessment of N1 nodes and, possibly, intrapulmonary lesions normally inaccessible to the conventional convex probe EBUS. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Sonoanatomical Change of Phrenic Nerve According to Posture During Ultrasound-Guided Stellate Ganglion Block

PubMed Central

Joeng, Eui Soo; Jeong, Young Cheol; Park, Bum Jun; Kang, Seok; Yang, Seung Nam

2016-01-01

Objective To evaluate the risk of phrenic nerve injury during ultrasound-guided stellate ganglion block (US-SGB) according to sonoanatomy of the phrenic nerve, and determine a safer posture for needle insertion by assessing its relationship with surrounding structure according to positional change. Methods Twenty-nine healthy volunteers were recruited and underwent ultrasound in two postures, i.e., supine position with the neck extension and head rotation, and lateral decubitus position. The transducer was placed at the anterior tubercle of the C6 level to identify phrenic nerve. The cross-sectional area (CSA), depth from skin, distance between phrenic nerve and anterior tubercle of C6 transverse process, and the angle formed by anterior tubercle, posterior tubercle and phrenic nerve were measured. Results The phrenic nerve was clearly identified in the intermuscular fascia layer between the anterior scalene and sternocleidomastoid muscles. The distance between the phrenic nerve and anterior tubercle was 10.33±3.20 mm with the supine position and 9.20±3.31 mm with the lateral decubitus position, respectively. The mean CSA and skin depth of phrenic nerve were not statistically different between the two positions. The angle with the supine position was 48.37°±27.43°, and 58.89°±30.02° with the lateral decubitus position. The difference of angle between the two positions was statistically significant. Conclusion Ultrasound is a useful tool for assessing the phrenic nerve and its anatomical relation with other cervical structures. In addition, lateral decubitus position seems to be safer by providing wider angle for needle insertion than the supine position in US-SGB. PMID:27152274

Sonoanatomical Change of Phrenic Nerve According to Posture During Ultrasound-Guided Stellate Ganglion Block.

PubMed

Joeng, Eui Soo; Jeong, Young Cheol; Park, Bum Jun; Kang, Seok; Yang, Seung Nam; Yoon, Joon Shik

2016-04-01

To evaluate the risk of phrenic nerve injury during ultrasound-guided stellate ganglion block (US-SGB) according to sonoanatomy of the phrenic nerve, and determine a safer posture for needle insertion by assessing its relationship with surrounding structure according to positional change. Twenty-nine healthy volunteers were recruited and underwent ultrasound in two postures, i.e., supine position with the neck extension and head rotation, and lateral decubitus position. The transducer was placed at the anterior tubercle of the C6 level to identify phrenic nerve. The cross-sectional area (CSA), depth from skin, distance between phrenic nerve and anterior tubercle of C6 transverse process, and the angle formed by anterior tubercle, posterior tubercle and phrenic nerve were measured. The phrenic nerve was clearly identified in the intermuscular fascia layer between the anterior scalene and sternocleidomastoid muscles. The distance between the phrenic nerve and anterior tubercle was 10.33±3.20 mm with the supine position and 9.20±3.31 mm with the lateral decubitus position, respectively. The mean CSA and skin depth of phrenic nerve were not statistically different between the two positions. The angle with the supine position was 48.37°±27.43°, and 58.89°±30.02° with the lateral decubitus position. The difference of angle between the two positions was statistically significant. Ultrasound is a useful tool for assessing the phrenic nerve and its anatomical relation with other cervical structures. In addition, lateral decubitus position seems to be safer by providing wider angle for needle insertion than the supine position in US-SGB.

Determining the acoustic properties of the lens using a high-frequency ultrasonic needle transducer.

PubMed

Huang, Chih-Chung; Zhou, Qifa; Ameri, Hossein; Wu, Da Wei; Sun, Lei; Wang, Shyh-Hau; Humayun, Mark S; Shung, K Kirk

2007-12-01

Ultrasonic parameters including sound velocity and attenuation coefficient have recently been found to be useful in characterizing the cataract lens noninvasively. However, the regional changes of these acoustic parameters in the lens cannot be detected directly by those ultrasonic measurements. This prompted us to fabricate a 46-MHz needle transducer (lead magnesium niobate-lead titanate [PMN-PT] single crystal) with an aperture size of 0.4 mm and a diameter of 0.9 mm for directly measuring the sound velocity and frequency-dependent attenuation coefficient in lenses. These parameters have been shown to be related to the hardness of a cataract, and hence this technique may allow surgeons to detect the acoustic properties of the cataract via a small incision on the cornea before/during phacoemulsification surgery. To verify the performance of the needle transducer, experiments were performed on porcine lenses in which two types of cataracts (nucleus and cortical) were induced artificially. The needle transducer was mounted on a positioning system and its tip was inserted into the lens, allowing the anterior-to-posterior profiles of acoustic parameters along the lens axis to be obtained immediately. The experimental results show that the acoustic parameters are not constant within a single normal lens. The sound velocity and ultrasound attenuation coefficient (at 46 MHz) were 1701.2 +/- 8.4 m/s (mean +/- SD) and 9.42 +/- 0.57 dB/mm, respectively, at the nucleus, and 1597.2 +/- 9.6, 1589.3 +/- 6.1 m/s and 0.42 +/- 0.26 and 0.40 +/- 0.33 dB/mm close to the anterior and posterior capsules, respectively. Finally, the data obtained demonstrate that regional variations in the acoustic properties of lenses corresponding to the hardness of different types of cataract can be detected sensitively by a needle transducer.

Robust superhydrophobic needle-like nanostructured ZnO surfaces prepared without post chemical-treatment

NASA Astrophysics Data System (ADS)

Velayi, Elmira; Norouzbeigi, Reza

2017-12-01

Robust superhydrophobic ZnO surfaces with micro/nano hybrid hierarchical structures were synthesized on the stainless steel mesh by a facile single-step chemical bath deposition (CBD) method without using further low surface energy materials. The Taguchi L16 experimental design was applied to evaluate the effects of reaction time, type and concentration of the additive, type of the chelating agent, and the molar ratio of the chelating agent to the initial zinc (II) ions. The prepared sample at the optimal conditions exhibited a sustainable and time-independent superhydrophobic behavior with the water contact angle (WCA) of 162.8° ± 2.5° and contact angle hysteresis (CAH) of 1.8° ± 0.5°. The XRD, SEM, TEM and FTIR analyses were used to characterize the prepared samples. Surface characterization using scanning electron microscopy (SEM) indicated accumulation of micro/nano branched ZnO needles on the substrate with the average diameters of ∼85 nm. After 20 abrasion cycles the optimum sample indicated an excellent mechanical robustness via exposure to the pressure of 4.7 kPa. A suitable chemical resistance to the acidic and basic droplets with the pH range of 4 and 9 was observed.

Ultrasound-guided thermocouple placement for cryosurgery.

PubMed

Abramovits, W; Pruiksma, R; Bose, S

1996-09-01

Although cryosurgical methods have high cure rates, imprecise estimates of both skin lesion depth and destructive temperature front location result in subjective technique in skin malignancy treatments. We evaluated the possibility of newer ultrasound equipment to assist in the precise placement of thermocouples in human skin. DermaScan C ver. 3 ultrasonographic equipment fitted with a sharp focus probe with a frequency of 20 MHz and a scan length of 12.1 mm was used to locate thermocouples with 27- and 30-gauge needles. We successfully and reproducibly located thermocouples and thin needles, and accurately measured their distance from the skin surface. Ultrasound is a useful method for the accurate placement of thermocouples, and needles as thin as 30 gauge for monitoring in cryosurgery.

Causes and Solutions of the Trampoline Effect.

PubMed

Miwa, Masamiki; Ota, Noboru; Ando, Chiyono; Miyazaki, Yukio

2015-01-01

A trampoline effect may occur mainly when a buttonhole tract and the vessel flap fail to form a straight line. Certain findings, however, suggest another cause is when the vessel flap is too small. The frequency of the trampoline effect, for example, is lower when a buttonhole tract is created by multiple punctures of the arteriovenous fistula (AVF) vessel than when it is done by one-time puncture of the vessel. Lower frequency of the trampoline effect with multiple punctures of the AVF vessel may be due to enlargement of the initial puncture hole on the vessel every time the vessel is punctured with a sharp needle. Even if aiming at exactly the same point on the AVF vessel every time, the actual puncture point shifts slightly at every puncture, which potentially results in enlargement of the initial hole on the AVF vessel. Moreover, in some patients, continued use of a buttonhole tract for an extended period of time increases the frequency of the trampoline effect. In such cases, reduction of the incidence of the trampoline effect can be achieved by one buttonhole cannulation using a new dull needle with sharp side edges that is used to enlarge the vessel flap. Such single buttonhole cannulation may suggest that the increased frequency of the trampoline effect also potentially occurs in association with gradually diminishing flap size. As a final observation, dull needle insertion into a vessel flap in the reverse direction has been more smoothly achieved than insertion into a vessel flap in the conventional direction. A vessel flap in the reverse direction can be adopted clinically. © 2015 S. Karger AG, Basel.

Smart surgical needle actuated by shape memory alloys for percutaneous procedures

NASA Astrophysics Data System (ADS)

Konh, Bardia

Background: Majority of cancer interventions today are performed percutaneously using needle-based procedures, i.e. through the skin and soft tissue. Insufficient accuracy using conventional surgical needles motivated researchers to provide actuation forces to the needle's body for compensating the possible errors of surgeons/physicians. Therefore, active needles were proposed recently where actuation forces provided by shape memory alloys (SMAs) are utilized to assist the maneuverability and accuracy of surgical needles. This work also aims to introduce a novel needle insertion simulation to predict the deflection of a bevel tip needle inside the tissue. Methods: In this work first, the actuation capability of a single SMA wire was studied. The complex response of SMAs was investigated via a MATLAB implementation of the Brinson model and verified via experimental tests. The material characteristics of SMAs were simulated by defining multilinear elastic isothermal stress-strain curves. Rigorous experiments with SMA wires were performed to determine the material properties as well as to show the capability of the code to predict a stabilized SMA transformation behavior with sufficient accuracy. The isothermal stress-strain curves of SMAs were simulated and defined as a material model for the Finite Element Analysis of the active needle. In the second part of this work, a three-dimensional finite element (FE) model of the active steerable needle was developed to demonstrate the feasibility of using SMA wires as actuators to bend the surgical needle. In the FE model, birth and death method of defining boundary conditions, available in ANSYS, was used to achieve the pre-strain condition on SMA wire prior to actuation. This numerical model was validated with needle deflection experiments with developed prototypes of the active needle. The third part of this work describes the design optimization of the active using genetic algorithm aiming for its maximum flexibility. Design parameters influencing the steerability include the needle's diameter, wire diameter, pre-strain, and its offset from the needle. A simplified model was developed to decrease the computation time in iterative analyses of the optimization algorithm. In the fourth part of this work a design of an active needling system was proposed where actuation forces of SMAs as well as shape memory polymers (SMPs) were incorporated. SMP elements provide two major additional advantages to the design: (i) recovery of the SMP's plastic deformation by heating the element above its glass transition temperature, and (ii) achieving a higher needle deflection by having a softer stage of SMP at higher temperatures with less amount of actuation force. Finally, in the fifth and last part of this study, an Arbitrary-Lagrangian-Eulerian formulation in LS-DYNA software was used to model the solid-fluid interactions between the needle and tissue. A 150mm long needle was considered to bend within the tissue due to the interacting forces on its asymmetric bevel tip. Some additional assumptions were made to maintain a reasonable computational time, with no need of parallel processing, while having practical accuracies. Three experimental tests of needle steering in a soft phantom were performed to validate the simulation. Results: The finite element model of the active needle was first validated experimentally with developed prototypes. Several design parameters affecting the needle's deflection such as the needle's Young's modulus, the SMA's pre-strain and its offset from the neutral axis of the cannula were studied using the FE model. Then by the integration of the SMA characteristics with the automated optimization schemes an improved design of the active needle was obtained. Real-time experiments with different prototypes showed that the quickest response and the maximum deflection were achieved by the needle with two sections of actuation compared to a single section of actuation. Also the feasibility of providing actuation forces using both SMAs and SMPs for the surgical needle was demonstrated in this study. The needle insertion simulation was validated while observing less than 10% deviation between the estimated amount of needle deflection by the simulation and by the experiments. Using this model the effect of needle diameter and its bevel tip angle on the final shape of the needle was investigated. Conclusion: The numerical and experimental studies of this work showed that a highly maneuverable active needle can be made using the actuation of multiple SMA wires in series. To maneuver around the anatomical obstacles of the human body and reach the target location, thin sharp needles are recommended as they would create a smaller radius of curvature. The insertion model presented in this work is intended to be used as a base structure for path planning and training purposes for future studies. (Abstract shortened by UMI.).

[Effects of Acupuncture Stimulation of Different Layers of "Tianshu" (ST 25) Region on Changes of Intra-colonic Pressure in Normal Rats].

PubMed

Sun, Xue-Yi; Yu, Zhi; Chen, Zhi-Yu; Xu, Bin

2018-02-25

To observe the effect of manual acupuncture stimulation of different layers (skin, muscle, peritoneum, sub-peritoneum) of "Tianshu" (ST 25) region on proximal colonic pressure in normal rats. Forty-eight male SD rats were divided into 6 groups: all layer-needling, brushing, cutaneous needling, muscular needling, peritoneum-needling and sub-peritoneum-needling groups ( n ＝8 in each group). Manual needling or brushing was applied to "Tianshu" (ST 25) region. The colonic internal pressure was measured by using an amplifier and a pressure transducer-connected balloon which was implanted into the colonic cavity about 6 cm from the ileocecal valve. For rats of the all-layer needling group, an acupuncture needle was inserted into ST 25 about 1 cm deep and rotated for a while, for rats of the brushing group, a Chinese calligraphy brush pen was used to brush the skin hair for 1 min. For rats of the rest 4 groups, an acupuncture needle was inserted into the skin, muscle layer after cutting open the skin (about 0.1 cm), the peritoneum layer after cutting open the skin and muscle layers, and the sub-peritoneum layer after cutting open the skin, muscle and peritoneum layers, respectively, and rotated using the uniform reinforcing-reducing technique for about 1 min at a frequency of 120 twirlings per minute every time. During manual needling stimulation of the full layers, cutaneous layer, muscle layer, peritoneum layer and the sub-peritoneum layer of bilateral "Tianshu" (ST 25), the internal pressure of proximal colon was significantly decreased relevant to pre-stimulation in each group ( P <0.05), and there were no significant differences between bilateral sides needling stimulation in the decreased pressure levels ( P >0.05). During hair brushing of ST 25 region, the colonic pressure was observably increased relevant to pre-needling stimulation ( P <0.05). One min after the acupuncture stimulation, the decreased pressures maintained in needling the all-layer on the left side, needling the skin on the right side, needling the peritoneum layer on both sides, and needling the sub-peritoneum layer on both sides relevant to the brushing group of the same side ( P <0.05). Manual acupuncture stimulation of each layer tissue of ST 25 on both sides may lower internal pressure of proximal colon in normal rats, suggesting their involvement of acupuncture effect in relaxing proximal colonic contraction.

Experimental and Numerical Study of Needle Peening Effects in Aluminium Alloy 2024-T3 Sheets

NASA Astrophysics Data System (ADS)

Mendez Romero, Julio Alberto

Peening of metallic components is an effective treatment used in aerospace and automotive applications to improve fatigue properties or to blend and repair localized damage. This process is typically carried out using metallic airborne media, called shot. However, different processes make use of different media, such is the case of hard, pneumatically powered needles of needle peening equipment. In order to obtain a better understanding of the effects of needle peening in the same context as shot peening, this research work had as an objective to study in detail the behavior of the needle peening equipment in order to characterize the process, design an experimental campaign to measure the effects of needle peening on AA2024-T3 and to develop and validate a Finite Element (FE) model capable of replicating the results of needle peening. The needle peening equipment prototype, called SPIKERRTM, was developed by Shockform Aeronautique Inc. The equipment was characterized by utilizing high-speed camera recording in order to study its behaviour by varying the operating pressure. The obtained collection of images was ran through a newly developed digital image algorithm, so as to quantify the needles' velocity and frequency. The impact velocity and impact frequency were determined for different equipment operating parameters. It was concluded that both the average impact velocity and the impact frequency increase as the pressure becomes larger. Behaviour anomalies among the different needles, such as frequency and velocity variations, were brought to light; these conclusions could be of interest to the manufacturer. Ideally, all of the needles should behave as similarly as possible so as to produce a more uniform process. The response to needle peening of AA2024-T3 in 1.6 mm thick sheet form was studied by needle peening test specimens with dimensions of an Almen strips using the SPIKERRTM. AA2024-T3 was selected since it was extensively studied at Ecole Polytechnique de Montreal as part of previous shot peening research. Saturation tests were done to determine the deflection at saturation for different peening parameters. The specimen deflection was measured using the standard Almen gauge used as part of routinary process control. Due to the aluminium magnetic incompatibility with the Almen gauge, the deformed specimen profile was measured using a Coordinate Measuring Machine (CMM). Repeatability of the process was demonstrated and the deflection at saturation, as well as the saturation time, was obtained. The indentation diameters created by impacts for different operating pressures were measured using microscopic photography. It was determined that the specimen deformation, as well as the indentation diameter, is larger when the operating pressure increases. Treatment of the test samples using the same peening parameters resulted in a variable indentation diameter. This is explained by the velocity variations detected during the equipment characterization. The added value that needle peening could provide to existing peening techniques is that, in principle, uniformity in the indentation diameters is easier to achieve as all impacts are normal and there is no loss of energy due to media interaction. The last experimental test was to determine the induced residual stress by means of X-ray Diffraction (XRD) for one specimen at saturation. An FE model heavily inspired by previous shot peening modeling was developed to simulate needle peening. The parameters obtained during the characterization of the equipment were taken as boundary conditions. Initially, the case of a single impacts was studied. Good accordance between the simulated and the average experimental indentation diameters was obtained, except for the lowest pressure studied. The overestimation of the indentation diameter could stem from the method used to measure the simulated diameter. Coverage estimation, and therefore indentation diameters remain an open line of research in shot peening simulation. Using the same model, it was demonstrated that the induced stress profile changes in depth and magnitude as impact velocity increases. Finally, the same model was used to study the development of residual stresses after multiple stochastic impacts at different velocities. Saturation was determined by obtaining the arc height created as as consequence of inducing the stresses determined by the impact model and obtaining a regression model that would best fit through the multiple simulation results. The residual stress profile at saturation for one of the scenarios was compared against the XRD results from the sample peened at the same operating pressure. The model was able to predict the surface residual stress (187 MPa) within 1.6% of the experimental results (184 MPa). The results for the remainder of the cases studied were then compared against the deflection measured using the CMM. The maximum deflection difference between the predicted and the experimental results was of 2% for the sample for which the residual stress profile was confirmed. For the lowest air pressure, an overestimation of 50% was seen, however the difference between experimental and predicted results rests between 0.3% and 13.2% for the remainder of the cases. To conclude, the methodology presented proves that it is possible to predict the induced stresses by needle peening, which in hand can be used to predict sample deflection.

Therapeutic effects of different durations of acupuncture on rats with middle cerebral artery occlusion

PubMed Central

Zhang, Chao; Wen, Yan; Fan, Xiao-nong; Tian, Guang; Zhou, Xue-yi; Deng, Shi-zhe; Meng, Zhi-hong

2015-01-01

Acupuncture is regarded as an effective therapy for cerebral ischemia. Different acupuncture manipulations and durations may result in different therapeutic effects. In the present study, the Neiguan (PC6) acupoint of rats with occluded middle cerebral arteries was needled at a fixed frequency (3 Hz) with different durations, i.e., 5, 60 and 180 seconds under a twisting-rotating acupuncture method. Results showed that different durations of acupuncture had different therapeutic effects, with 60 seconds yielding a better therapeutic effect than the other two groups. This duration of treatment demonstrated rapid cerebral blood flow, encouraging recovery of neurological function, and small cerebral infarct volume. Experimental findings indicated that under 3 Hz frequency, the treatment of needling Neiguan for 60 seconds is effective for ischemic stroke. PMID:25788938

Atmospheric pressure plasma jet's characterization and surface wettability driven by neon transformer

NASA Astrophysics Data System (ADS)

Elfa, R. R.; Nafarizal, N.; Ahmad, M. K.; Sahdan, M. Z.; Soon, C. F.

2017-03-01

Atmospheric pressure plasma driven by Neon transformer power supply argon is presented in this paper. Atmospheric pressure plasma system has attracted researcher interest over low pressure plasma as it provides a flexibility process, cost-efficient, portable device and vacuum-free device. Besides, another golden key of this system is the wide promising application in the field of work cover from industrial and engineering to medical. However, there are still numbers of fundamental investigation that are necessary such as device configuration, gas configuration and its effect. Dielectric barrier discharge which is also known as atmospheric pressure plasma discharge is created when there is gas ionization process occur which enhance the movement of atom and electron and provide energetic particles. These energetic particles can provide modification and cleaning property to the sample surface due to the bombardment of the high reactive ion and radicals to the sample surface. In order to develop atmospheric pressure plasma discharge, a high voltage and high frequency power supply is needed. In this work, we used a neon transformer power supply as the power supply. The flow of the Ar is feed into 10 mm cylinder quartz tube with different treatment time in order to investigate the effect of the plasma discharge. The analysis of each treatment time is presented by optical emission spectroscopy (OES) and water contact angle (WCA) measurement. The increase of gas treatment time shows increases intensity of reactive Ar and reduces the angle of water droplets in water contact angle. Treatment time of 20 s microslide glass surface shows that the plasma needle discharges have modified the sample surface from hydrophilic surface to superhydrophilic surface. Thus, this leads to another interesting application in reducing sample surface adhesion to optimize productivity in the industry of paintings, semiconductor and more.

Disinfection of S. mutans Bacteria Using a Plasma Needle at Atmospheric Pressure

NASA Astrophysics Data System (ADS)

Hansen, S.; Goree, J.; Liu, Bin; Drake, D.

2007-11-01

The plasma needle device produces a millimeter-size low-power glow discharge at atmospheric-pressure. It is intended for dental or medical applications. Radio-frequency high voltage is applied to a single needle electrode located inside a concentric gas-flow nozzle. A low-speed helium plasma jet flows out of the nozzle and mixes with ambient air. The jet is impinges on a surface that is to be treated, which in our test was a suspension of S. mutans bacteria that was plated onto the surface of agar nutrient in a Petri dish. S. mutans is the most important microorganism for causing dental caries. Imaging the sample after plasma treatment and incubation reveal the conditions where bacteria are killed, and the size of the treated spot.

Choledochoscopic high-frequency needle-knife electrotomy for treatment of anastomotic strictures after Roux-en-Y hepaticojejunostomy.

PubMed

Yang, Yu-Long; Zhang, Cheng; Wu, Ping; Ma, Yue-Feng; Li, Jing-Yi; Zhang, Hong-Wei; Shi, Li-Jun; Lin, Mei-Ju; Yu, Ying

2016-05-06

Anastomotic stricture is a complex and substantial complication following Roux-en-Y hepaticojejunostomy. Initially, endoscopic and percutaneous approaches are often attempted, but the gold standard remains surgical biliary reconstruction, especially for refractory stricture. However, this solution leaves much room for improvement, due to the challenging nature of the biliary reconstruction procedure, in which anastomotic stricture may still occur. To investigate the feasibility and effectiveness of choledochoscopic high-frequency needle-knife electrotomy as an intervention in the treatment of anastomotic strictures following Roux-en-Y hepaticojejunostomy. From February 2010 to October 2014, clinical data was collected and retrospectively compared for patients who underwent balloon dilation or/and choledochoscopic high-frequency needle-knife electrotomy for the treatment of anastomotic strictures after Roux-en-Y hepaticojejunostomy. A total of 38 patients underwent successful choledochoscopic treatment and all the anastomotic strictures were removed successfully, 19 of which were treated with electrotomy, 7 with balloon dilation, and 12 with both electrotomy and balloon dilation. Among these groups,the average operating times were 6.9 ± 2.4 min,10.1 ± 6.8 min, and 20.2 ± 13.5 min, respectively. The average stent supporting times were 6.3 ± 0.7 months, 6.5 ± 0.6 months, and 6.1 ± 0.4 respectively. The mean follow-up after stent removal was 42.1 ± 27.4 months, and in 26.3 % (5/19), 28.5 % (2/7) and 16.7 % (2/12) of cases, recurrent anastomotic stricture occurred. Of these 9 total patients with recurrent anastomotic, two patients were successfully rescued by full-covered self-expanding removable metal stents and 7 patients by electrotomy combined with balloon dilation. Choledochoscopic high-frequency needle-knife electrotomy is both feasible and safe in the treatment of anastomotic stricture after Roux-en-Y hepaticojejunostomy, with a similar long-term outcome to balloon dilation in treating anastomotic stricture after Roux-en-Y hepaticojejunostomy. A combination of choledochoscopic electrotomy concurrent with balloon dilation should be recommended based on the low rate of recurrence.

Postdural puncture headache: a randomized prospective comparison of the 24 gauge Sprotte and the 27 gauge Quincke needles in young patients.

PubMed

Wiesel, S; Tessler, M J; Easdown, L J

1993-07-01

This study was designed to compare the frequency of postdural puncture headaches (PDPH) using the 24 gauge Sprotte and the 27 gauge Quincke spinal needles in a population of patients less than 45 yr of age undergoing spinal anaesthesia for non-obstetrical surgery. Patients were randomly assigned to receive spinal anaesthesia with either the 24 gauge Sprotte spinal needle (n = 46) or the 27 gauge Quincke spinal needle (n = 47). Patients were interviewed on either postoperative day one or two and on postoperative day three. A PDPH was defined as a headache involving the occipital or frontal areas that is made worse when assuming either the sitting or standing position. Ninety-three patients were included in the analysis of data. The overall incidence of PDPH was 14% (13 of 93), and no difference was found between the Sprotte (15.2%) and Quincke (12.8%) needles. The distribution of the PDPHs by severity was not different between the two groups. None of the 13 patients with PDPHs required on epidural blood patch for relief of symptoms. Both the Sprotte needle and the Quincke needles were judged as easy to use and both required the same number of attempts in order to locate cerebrospinal fluid (first attempt successful: 73.9% versus 66%). Neither patient satisfaction nor the acceptability of spinal anaesthesia for a future procedure was adversely affected by the occurrence of a PDPH. The results of this study suggest that the risk of PDPH after spinal anaesthesia in young patients is similar using either the 24 gauge Sprotte or the 27 gauge Quincke spinal needle.

Assessing the Effects of Acupuncture by Comparing Needling the Hegu Acupoint and Needling Nearby Nonacupoints by Spectral Analysis of Microcirculatory Laser Doppler Signals

PubMed Central

Hsiu, Hsin; Hsu, Wei-Chen; Hsu, Chia-Liang; Huang, Shih-Min

2011-01-01

We aimed to assess the effects of acupuncture by analyzing the frequency content of skin blood-flow signals simultaneously recorded at the Hegu acupoint and two nearby nonacupoints following acupuncture stimulation (AS). Laser Doppler flowmetry (LDF) signals were measured in male healthy volunteers in two groups of experiments: needling the Hegu acupoint (n = 13) and needling a nearby nonacupoint (control experiment; n = 10). Each experiment involved recording a 20 min baseline-data sequence and two sets of effects data recorded 0–20 and 50–70 min after stopping AS. Wavelet transform with Morlet mother wavelet was applied to the measured LDF signals. Needling the Hegu acupoint significantly increased the blood flow, significantly decreased the relative energy contribution at 0.02–0.06 Hz and significantly increased the relative energy contribution at 0.4–1.6 Hz at Hegu, but induced no significant changes at the nonacupoints. Also, needling a nearby nonacupoint had no effect in any band at any site. This is the first time that spectral analysis has been used to investigate the microcirculatory blood-flow responses induced by AS, and has revealed possible differences in sympathetic nerve activities between needling the Hegu acupoint and its nearby nonacupoint. One possible weakness of the present design is that different De-Qi feelings following AS could lead to nonblind experimental setup, which may bias the comparison between needling Hegu and its nearby nonacupoint. Our results suggest that the described noninvasive method can be used to evaluate sympathetic control of peripheral vascular activity, which might be useful for studying the therapeutic effects of AS. PMID:21804856

Infraorbital Foramen and Pterygopalatine Fossa Location in Dry Skulls: Anatomical Guidelines for Local Anesthesia

PubMed Central

2017-01-01

Purpose The aim of the study was to locate the infraorbital foramen (IOF) in relation to the infraorbital margin (IOM) for proper injections of local anesthetics in skull specimens. Another aim was to determine the depth of needle penetration into pterygopalatine fossa through the greater palatine canal (GPC). Materials and Methods 102 skull halves were used to measure the distances between (1) IOF and IOM and (2) IOF and alveolar ridge of maxilla at second premolar. Needles were inserted and bent at a 45° angle, passing through the GPC at the level of hard palate. The depth of the tip of needle emerging out of GPC into pterygopalatine fossa was measured. Results The mean distance between IOF and IOM was 6.46 ± 1.57 mm on the right side and 6.74 ± 1.72 mm on the left. The mean distance between IOF and alveolar bone process of the maxilla at second premolar was 29.07 ± 3.58 mm on the right side and 29.39 ± 3.78 mm on the left. The mean depth of penetration of the needle into the pterygopalatine fossa was similar on both sides. Conclusions Proper identification of IOF and pterygopalatine fossa is of great significance during local anesthesia injections, due to their close proximity to vital anatomic structures. PMID:29410916

Effects of Axial Vibration on Needle Insertion into the Tail Veins of Rats and Subsequent Serial Blood Corticosterone Levels

PubMed Central

Clement, Ryan S; Unger, Erica L; Ocón-Grove, Olga M; Cronin, Thomas L; Mulvihill, Maureen L

2016-01-01

Blood collection is commonplace in biomedical research. Obtaining sufficient sample while minimizing animal stress requires significant skill and practice. Repeated needle punctures can cause discomfort and lead to variable release of stress hormones, potentially confounding analysis. We designed a handheld device to reduce the force necessary for needle insertion by using low-frequency, axial (forward and backward) micromotions (that is, vibration) delivered to the needle during venipuncture. Tests with cadaver rat-tail segments (n = 18) confirmed that peak insertion forces were reduced by 73% on average with needle vibration. A serial blood-sampling study was then conducted by using Sprague–Dawley rats divided into 2 groups based on needle condition used to cause bleeds: vibration on (n = 10) and vibration off (n = 9). On 3 days (1 wk apart), 3 tail-vein blood collections were performed in each subject at 1-h intervals. To evaluate associated stress levels, plasma corticosterone concentration was quantified by radioimmunoassay and behavior (that is, movement and vocalization) was scored by blinded review of blood-sampling videos. After the initial trial, average corticosterone was lower (46% difference), the mean intrasubject variance trended lower (72%), and behavioral indications of stress were rated lower for the vibration-on group compared with the vibration-off group. Adding controlled vibrations to needles during insertion may decrease the stress associated with blood sampling from rats—an important methodologic advance for investigators studying and assessing stress processes and a refinement over current blood sampling techniques. PMID:27025813

Choledochoscopic high-frequency needle-knife electrotomy as an effective treatment for intrahepatic biliary strictures.

PubMed

Yang, Yu-Long; Zhang, Cheng; Zhao, Gang; Wu, Ping; Ma, Yue-Feng; Zhang, Hong-Wei; Shi, Li-Jun; Li, Jing-Yi; Lin, Mei-Ju; Yang, Shi-Ming; Lv, Yi

2015-09-01

Hepatolithiasis is associated with the presence of intrahepatic biliary strictures, and balloon dilatation is the main approach. However, this method is difficult to implement if the bile duct distal to the stricture is blocked by stones. Therefore, alternative methods need to be explored to effectively treat hepatolithiasis. The aim of this study is to investigate the feasibility and effectiveness of choledochoscopic high-frequency needle-knife electrotomy for the treatment of intrahepatic biliary strictures. Clinical data of 58 patients suffering from intrahepatic bile duct strictures from January 2011 to January 2013 were retrospectively analyzed. Choledochoscopic electrotomy was used to resolve the strictures. One hundred thirty-four sites of intrahepatic bile duct strictures were discovered. The average operating time of electrotomy is 5.6 min (range, 1 ∼ 15 min). Structured bile duct tissue bleeding occurred in eight sites (8/134, 6.0%) but were resolved by endoscopic high-frequency electric cautery. After the operations, 14 cases of cholangitis (14/58, 24.1%), three cases of delayed hemobilia, one case of liver abscess (1/58, 1.7%), and seven cases of stenting exodus (7/58, 12.1%) were observed despite conservative treatment and stenting reset. The average supporting time was 7.0 months (6 ∼ 9 months). No abnormal bile duct structure or presence of stone was found according to choledochoscopy. The follow-up period ranged from 12 to 48 months. Hepatolithiasis recurred in five (5/58, 8.6%) patients, and the cumulative recurrent probability of intrahepatic bile duct stricture was 5.2% (7/134). Choledochoscopic high-frequency needle-knife electrotomy could be considered as a simple, safe, and effective complementary approach for treating intrahepatic biliary strictures. © 2015 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.

[Analysis of optimal plan of multiple acupuncture manipulations for shoulder pain after stroke at different stages].

PubMed

Chen, Dachun; Gao, Jianyu; Chen, Lu; Hao, Zhuanzhuan; Fan, Gangqi

2015-12-01

To observe the effects between acupuncture combined with rehabilitation and simple rehabilitation for shoulder pain after stroke, and to select the best plan of acupuncture manipulations at different stages by orthogonal design. Ninety patients were treated with comprehensive rehabilitation, and nine cases without acupuncture were arranged into a control group. Eighty-one patients of orthogonal design were applied by acupuncture with the same acupoints and course. The VAS score and its weighted value were regarded as the observation indices,and the effects between the acupuncture group and the control group were compared. The optimal plans of acupuncture manipulations of the early stage and the later stage were chosen after the first course treatment and the third course treatment separately. The acupuncture depth (factor A:A: shallow depth less than 25 mm, A(II): modest depth 25-40 mm, A(III): deep depth 40-50 mm), the acupuncture angle (factor B:B(I): perpendicular insertion, B(II): horizontal insertion, B(III): oblique insertion), needle manipulated frequency (factor C: C(I): zero time, C(II): one time, C(III): three times) and needle retained time(factor D:D(I):20 min, D(II): 30 min, D(III): 60 min) were studied. The differences among all factors and the diversity among major factors at different stages were analyzed. (1) Acupuncture combined with rehabilitation at the early and the later stage acquired better improvement than simple rehabilitation (all P < 0.01). (2) The optimal acupuncture manipulation plan at the early stage was A(III) B(III) C(I) D(I), which was deep acupuncture and oblique insertion for 20 min with zero-time manipulation; the optimal acupuncture manipulation plan at the later stage was A(III) B(III) C(III) D(I), which was deep acupuncture and oblique insertion for 20 min with three-time manipulation. (3) There was significance for acupuncture depth and angle at the early stage (both P < 0.01) and there was significance for insertion depth, acupuncture angle and manipulating frequency at the later stage (all P < 0.05). (4) At the early stage, the insertion depth was statistically significant between A(I) and A(II), A(I) and A(III), A(II) and A(III) (P < 0.05, P < 0.01), and the statistical significance was existed between B(I) and B(III) (P < 0.01). At the later stage, the insertion depth was statistically significant between A(I) and A(III), A(III) and A(II), A(I) and A(II) (P < 0.05, P < 0.01), and the statistical significance was existed between C(I) and C(III), C(II) and C(III) (P < 0.05). Acupuncture combined with rehabilitation acquire apparent effect for shoulder pain after stroke. At the early stage,the optimal plan is deep and oblique insertion for 20 min with zero-time manipulation. At the later stage, the best plan is deep and oblique insertion for 20 min with 3-time manipulation.

Design and Fabrication of a Hybrid Superhydrophobic-Hydrophilic Surface That Exhibits Stable Dropwise Condensation.

PubMed

Mondal, Bikash; Mac Giolla Eain, Marc; Xu, QianFeng; Egan, Vanessa M; Punch, Jeff; Lyons, Alan M

2015-10-28

Condensation of water vapor is an essential process in power generation, water collection, and thermal management. Dropwise condensation, where condensed droplets are removed from the surface before coalescing into a film, has been shown to increase the heat transfer efficiency and water collection ability of many surfaces. Numerous efforts have been made to create surfaces which can promote dropwise condensation, including superhydrophobic surfaces on which water droplets are highly mobile. However, the challenge with using such surfaces in condensing environments is that hydrophobic coatings can degrade and/or water droplets on superhydrophobic surfaces transition from the mobile Cassie to the wetted Wenzel state over time and condensation shifts to a less-effective filmwise mechanism. To meet the need for a heat-transfer surface that can maintain stable dropwise condensation, we designed and fabricated a hybrid superhydrophobic-hydrophilic surface. An array of hydrophilic needles, thermally connected to a heat sink, was forced through a robust superhydrophobic polymer film. Condensation occurs preferentially on the needle surface due to differences in wettability and temperature. As the droplet grows, the liquid drop on the needle remains in the Cassie state and does not wet the underlying superhydrophobic surface. The water collection rate on this surface was studied using different surface tilt angles, needle array pitch values, and needle heights. Water condensation rates on the hybrid surface were shown to be 4 times greater than for a planar copper surface and twice as large for silanized silicon or superhydrophobic surfaces without hydrophilic features. A convection-conduction heat transfer model was developed; predicted water condensation rates were in good agreement with experimental observations. This type of hybrid superhydrophobic-hydrophilic surface with a larger array of needles is low-cost, robust, and scalable and so could be used for heat transfer and water collection applications.

The natural frequencies of symmetric angle-ply laminates derived from eigensensitivity analysis

NASA Technical Reports Server (NTRS)

Reiss, Robert; Ramachandran, S.; Qian, BO

1988-01-01

In this paper, a new closed-form approximate solution for the natural frequencies of symmetric rectangular angle-ply laminates simply supported on all four edges is derived. The solution, obtained from eigensensitivity analysis, is expressed as a truncated Fourier series in the ply angle. Results show that the prediction for the fundamental frequency is quite accurate for engineering applications, often within 1-2 percent of the true frequency.

Research of misalignment between dithered ring laser gyro angle rate input axis and dither axis

NASA Astrophysics Data System (ADS)

Li, Geng; Wu, Wenqi; FAN, Zhenfang; LU, Guangfeng; Hu, Shaomin; Luo, Hui; Long, Xingwu

2014-12-01

The strap-down inertial navigation system (SINS), especially the SINS composed by dithered ring laser gyroscope (DRLG) is a kind of equipment, which providing high reliability and performance for moving vehicles. However, the mechanical dither which is used to eliminate the "Lock-In" effect can cause vibration disturbance to the INS and lead to dithering coupling problem in the inertial measurement unit (IMU) gyroscope triad, so its further application is limited. Among DRLG errors between the true gyro rotation rate and the measured rotation rate, the frequently considered one is the input axis misalignment between input reference axis which is perpendicular to the mounting surface and gyro angular rate input axis. But the misalignment angle between DRLG dither axis and gyro angular rate input axis is often ignored by researchers, which is amplified by dither coupling problem and that would lead to negative effects especially in high accuracy SINS. In order to study the problem more clearly, the concept of misalignment between DRLG dither axis and gyro angle rate input axis is researched. Considering the error of misalignment is of the order of 10-3 rad. or even smaller, the best way to measure it is using DRLG itself by means of an angle exciter as an auxiliary. In this paper, the concept of dither axis misalignment is explained explicitly firstly, based on this, the frequency of angle exciter is induced as reference parameter, when DRLG is mounted on the angle exciter in a certain angle, the projections of angle exciter rotation rate and mechanical oscillation rate on the gyro input axis are both sensed by DRLG. If the dither axis has misalignment error with the gyro input axis, there will be four major frequencies detected: the frequency of angle exciter, the dither mechanical frequency, sum and difference frequencies of the former two frequencies. Then the amplitude spectrum of DRLG output signal obtained by the using LabVIEW program. if there are only angle exciter and the dither mechanical frequencies, the misalignment may be too small to be detected, otherwise, the amplitude of the sum and difference frequencies will show the misalignment angle between the gyro angle rate input axis and the dither axis. Finally, some related parameters such as frequency and amplitude of the angle exciter and sample rate are calculated and the results are analyzed. The simulation and experiment result prove the effectiveness of the proposed method..

Design and optimization of a brachytherapy robot

NASA Astrophysics Data System (ADS)

Meltsner, Michael A.

Trans-rectal ultrasound guided (TRUS) low dose rate (LDR) interstitial brachytherapy has become a popular procedure for the treatment of prostate cancer, the most common type of non-skin cancer among men. The current TRUS technique of LDR implantation may result in less than ideal coverage of the tumor with increased risk of negative response such as rectal toxicity and urinary retention. This technique is limited by the skill of the physician performing the implant, the accuracy of needle localization, and the inherent weaknesses of the procedure itself. The treatment may require 100 or more sources and 25 needles, compounding the inaccuracy of the needle localization procedure. A robot designed for prostate brachytherapy may increase the accuracy of needle placement while minimizing the effect of physician technique in the TRUS procedure. Furthermore, a robot may improve associated toxicities by utilizing angled insertions and freeing implantations from constraints applied by the 0.5 cm-spaced template used in the TRUS method. Within our group, Lin et al. have designed a new type of LDR source. The "directional" source is a seed designed to be partially shielded. Thus, a directional, or anisotropic, source does not emit radiation in all directions. The source can be oriented to irradiate cancerous tissues while sparing normal ones. This type of source necessitates a new, highly accurate method for localization in 6 degrees of freedom. A robot is the best way to accomplish this task accurately. The following presentation of work describes the invention and optimization of a new prostate brachytherapy robot that fulfills these goals. Furthermore, some research has been dedicated to the use of the robot to perform needle insertion tasks (brachytherapy, biopsy, RF ablation, etc.) in nearly any other soft tissue in the body. This can be accomplished with the robot combined with automatic, magnetic tracking.

Sci-Thur PM – Brachytherapy 02: Positional accuracy in Pd-103 permanent breast seed implant (PBSI) brachytherapy at the Tom Baker Cancer Centre (TBCC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frederick, Amy; Watt, Elizabeth; Peacock, Michael

Purpose: This retrospective study aims to quantify the positional accuracy of seed delivery in permanent breast seed implant (PBSI) brachytherapy at the Tom Baker Cancer Centre (TBCC). Methods: Treatment planning and post-implant CT scans for 5 patients were rigidly registered using the MIM Symphony™ software (MIM Software, Cleveland, OH) and used to evaluate differences between planned and implanted seed positions. Total and directional seed displacements were calculated for each patient in a clinically relevant ‘needle coordinate system’, defined relative to the angle of fiducial needle insertion. Results: The overall average total seed displacement was 10±8 mm. Systematic seed displacements weremore » observed in individual patients and the magnitude and direction of these offsets varied among patients. One patient showed a significant directional seed displacement in the shallow-deep direction compared with the other four patients. With the exception of this one patient outlier, no significant systematic directional displacements in the needle coordinate system were observed for this cohort; the average directional displacements were −1±5 mm, 2±3 mm, and −2±4 mm in the shallow-deep, up-down, and right-left directions respectively. Conclusion: With the exception of one patient outlier, the magnitude of seed displacements were relatively consistent among patients. The results indicate that the shallow-deep direction possesses the largest uncertainty for the seed delivery method used at the TBCC. The relatively large uncertainty in seed placement in this direction is expected, as this is the direction of needle insertion. Further work will involve evaluating deflections of delivered needle tracks from their planned positions.« less

Characterization of scintillator-based detectors for few-ten-keV high-spatial-resolution x-ray imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larsson, Jakob C., E-mail: jakob.larsson@biox.kth.se; Lundström, Ulf; Hertz, Hans M.

2016-06-15

Purpose: High-spatial-resolution x-ray imaging in the few-ten-keV range is becoming increasingly important in several applications, such as small-animal imaging and phase-contrast imaging. The detector properties critically influence the quality of such imaging. Here the authors present a quantitative comparison of scintillator-based detectors for this energy range and at high spatial frequencies. Methods: The authors determine the modulation transfer function, noise power spectrum (NPS), and detective quantum efficiency for Gadox, needle CsI, and structured CsI scintillators of different thicknesses and at different photon energies. An extended analysis of the NPS allows for direct measurements of the scintillator effective absorption efficiency andmore » effective light yield as well as providing an alternative method to assess the underlying factors behind the detector properties. Results: There is a substantial difference in performance between the scintillators depending on the imaging task but in general, the CsI based scintillators perform better than the Gadox scintillators. At low energies (16 keV), a thin needle CsI scintillator has the best performance at all frequencies. At higher energies (28–38 keV), the thicker needle CsI scintillators and the structured CsI scintillator all have very good performance. The needle CsI scintillators have higher absorption efficiencies but the structured CsI scintillator has higher resolution. Conclusions: The choice of scintillator is greatly dependent on the imaging task. The presented comparison and methodology will assist the imaging scientist in optimizing their high-resolution few-ten-keV imaging system for best performance.« less

Characterization of scintillator-based detectors for few-ten-keV high-spatial-resolution x-ray imaging.

PubMed

Larsson, Jakob C; Lundström, Ulf; Hertz, Hans M

2016-06-01

High-spatial-resolution x-ray imaging in the few-ten-keV range is becoming increasingly important in several applications, such as small-animal imaging and phase-contrast imaging. The detector properties critically influence the quality of such imaging. Here the authors present a quantitative comparison of scintillator-based detectors for this energy range and at high spatial frequencies. The authors determine the modulation transfer function, noise power spectrum (NPS), and detective quantum efficiency for Gadox, needle CsI, and structured CsI scintillators of different thicknesses and at different photon energies. An extended analysis of the NPS allows for direct measurements of the scintillator effective absorption efficiency and effective light yield as well as providing an alternative method to assess the underlying factors behind the detector properties. There is a substantial difference in performance between the scintillators depending on the imaging task but in general, the CsI based scintillators perform better than the Gadox scintillators. At low energies (16 keV), a thin needle CsI scintillator has the best performance at all frequencies. At higher energies (28-38 keV), the thicker needle CsI scintillators and the structured CsI scintillator all have very good performance. The needle CsI scintillators have higher absorption efficiencies but the structured CsI scintillator has higher resolution. The choice of scintillator is greatly dependent on the imaging task. The presented comparison and methodology will assist the imaging scientist in optimizing their high-resolution few-ten-keV imaging system for best performance.

Frequency-dependent changes in sensorimotor and pain affective systems induced by empathy for pain.

PubMed

Motoyama, Yoshimasa; Ogata, Katsuya; Hoka, Sumio; Tobimatsu, Shozo

2017-01-01

Empathy for pain helps us to understand the pain of others indirectly. To better comprehend the processing of empathic pain, we report the frequency-dependent modulation of cortical oscillations induced by watching movies depicting pain using high-density electroencephalography (EEG), magnetoencephalography (MEG), and motor evoked potentials (MEP). Event-related desynchronization of EEG and MEG was assessed while participants viewed videos of painful (needle) or neutral (cotton swab) situations. The amplitudes of MEPs were also compared between the needle and cotton swab conditions. The degree of suppression in α/β band power was significantly increased, whereas that of γ band power was significantly decreased, in the needle condition compared with the cotton swab condition. EEG revealed that significant differences in α/β band were distributed in the right frontocentral and left parietooccipital regions, whereas significant γ band differences were distributed predominantly over the right hemisphere, which were confirmed by source estimation using MEG. There was a significant positive correlation between the difference in γ power of the two conditions and the visual analog scale subjective rating of aversion, but not in the α/β band. The amplitude of MEPs decreased in the needle condition, which confirmed the inhibition of the primary motor cortex. MEP suppression supports that modulation of cortical oscillations by viewing movies depicting pain involves sensorimotor processing. Our results suggest that α/β oscillations underlie the sensory qualities of others' pain, whereas the γ band reflects the cognitive aspect. Therefore, α/β and γ band oscillations are differentially involved in empathic pain processing under the condition of motor cortical suppression.

Evaluation of forest nutrition based on large-scale foliar surveys: are nutrition profiles the way of the future?

PubMed

Luyssaert, Sebastiaan; Sulkava, Mika; Raitio, Hannu; Hollmén, Jaakko

2004-02-01

This paper introduces the use of nutrition profiles as a first step in the development of a concept that is suitable for evaluating forest nutrition on the basis of large-scale foliar surveys. Nutrition profiles of a tree or stand were defined as the nutrient status, which accounts for all element concentrations, contents and interactions between two or more elements. Therefore a nutrition profile overcomes the shortcomings associated with the commonly used concepts for evaluating forest nutrition. Nutrition profiles can be calculated by means of a neural network, i.e. a self-organizing map, and an agglomerative clustering algorithm with pruning. As an example, nutrition profiles were calculated to describe the temporal variation in the mineral composition of Scots pine and Norway spruce needles in Finland between 1987 and 2000. The temporal trends in the frequency distribution of the nutrition profiles of Scots pine indicated that, between 1987 and 2000, the N, S, P, K, Ca, Mg and Al decreased, whereas the needle mass (NM) increased or remained unchanged. As there were no temporal trends in the frequency distribution of the nutrition profiles of Norway spruce, the mineral composition of the needles of Norway spruce needles subsequently did not change. Interpretation of the (lack of) temporal trends was outside the scope of this example. However, nutrition profiles prove to be a new and better concept for the evaluation of the mineral composition of large-scale surveys only when a biological interpretation of the nutrition profiles can be provided.

Controlling the angle range in acoustic low-frequency forbidden transmission in solid-fluid superlattice

NASA Astrophysics Data System (ADS)

Zhang, Sai; Xu, Bai-qiang; Cao, Wenwu

2018-03-01

We have investigated low-frequency forbidden transmission (LFT) of acoustic waves with frequency lower than the first Bragg bandgap in a solid-fluid superlattice (SFSL). LFT is formed when the acoustic planar wave impinges on the interface of a SFSL within a certain angle range. However, for the SFSL comprised of metallic material and water, the angle range of LFT is extremely narrow, which restricts its practical applications. The variation characteristics of the angle range have been comprehensively studied here by the control variable method. The results suggest that the filling ratio, layer number, wave velocity, and mass density of the constituent materials have a significant impact on the angle range. Based on our results, an effective strategy for obtaining LFT with a broad angle range is provided, which will be useful for potential applications of LFT in various devices, such as low frequency filters and subwavelength one-way diodes.

Technical feasibility of endoscopic submucosal dissection of gastrointestinal epithelial neoplasms with a splash-needle.

PubMed

Fujishiro, Mitsuhiro; Kodashima, Shinya; Goto, Osamu; Ono, Satoshi; Muraki, Yosuke; Kakushima, Naomi; Omata, Masao

2008-12-01

Endoscopic submucosal dissection (ESD) permits the resection of large gastrointestinal epithelial neoplasms and neoplasms with submucosal fibrosis in an en bloc manner. However, the high frequency of complications accompanying ESD and its complex processes suggests that the process requires improvement. A total of 22 consecutive patients with gastrointestinal epithelial neoplasms were enrolled during a 6-month period to evaluate a novel endosurgical knife for ESD. This novel knife is known as the "splash-needle," and it is thin, short needle with a water-irrigation function. The technical results revealed that the rates of bloc resection and en bloc resection with tumor-free lateral/basal margins (R0 resection) were 91% (20/22) and 82% (18/22), respectively. There was no significant bleeding or perforation during or after ESD. The median operation time was 60 minutes (range, 20 to 210). The splash-needle is a promising novel endosurgical knife that is useful for less complicated ESD. The accumulation of knowledge and cases verifying its usefulness is necessary, and a study comparing the knife with first-generation endosurgical knives is also warranted.

Bactericial effect of a non-thermal plasma needle against Enterococcus faecalis biofilms

NASA Astrophysics Data System (ADS)

Jiang, Chunqi; Schaudinn, C.; Jaramillo, D. E.; Sedghizadeh, P. P.; Webster, P.; Costerton, J. W.

2011-10-01

Up to 3 cm long submillimeter-in-scale plasma needle was generated in ambient atmosphere for root canal disinfection. Powered with 1-2 kHz, multi-kilovolt nanosecond electric pulses, this He/(1%)O2 plasma jet consists of ionization fronts propagating at speeds of the order of 107 cm/s. Plasma treatment of Enterococcus faecalis biofilms on hydroxyapatite (HA) discs for 5 min resulted in severe damage of the bacterial cells and sterilized HA surfaces of more than 3 mm in diameter, observed by the scanning electron microscopy. With a curing dielectric microtube placed 1 cm or less below the nozzle, the plasma jet entered even at a sharp angle and followed the curvature of the tube, and reached the bottom of the tube. The bactericidal effect of the plasma needle against E. faecalis biofilm grown on the inner surfaces of the tube was demonstrated. However, the bactericidal effect weakens or diminishes for the bacteria grown deeper in the tube, indicating improvement of the plasma treatment scheme is needed. Mechanisms of the plasma bactericidal effects are discussed. Supported by the National Institute of Dental and Craniofacial Research and the Air Force Office of Scientific Research.

An HR-MAS MR Metabolomics Study on Breast Tissues Obtained with Core Needle Biopsy

PubMed Central

Cho, Nariya; Chang, Jung Min; Koo, Hye Ryoung; Yi, Ann; Kim, Hyeonjin; Park, Sunghyouk; Moon, Woo Kyung

2011-01-01

Background Much research has been devoted to the development of new breast cancer diagnostic measures, including those involving high-resolution magic angle spinning (HR-MAS) magnetic resonance (MR) spectroscopic techniques. Previous HR-MAS MR results have been obtained from post-surgery samples, which limits their direct clinical applicability. Methodology/Principal Findings In the present study, we performed HR-MAS MR spectroscopic studies on 31 breast tissue samples (13 cancer and 18 non-cancer) obtained by percutaneous core needle biopsy. We showed that cancer and non-cancer samples can be discriminated very well with Orthogonal Projections to Latent Structure-Discriminant Analysis (OPLS-DA) multivariate model on the MR spectra. A subsequent blind test showed 69% sensitivity and 94% specificity in the prediction of the cancer status. A spectral analysis showed that in cancer cells, taurine- and choline-containing compounds are elevated. Our approach, additionally, could predict the progesterone receptor statuses of the cancer patients. Conclusions/Significance HR-MAS MR metabolomics on intact breast tissues obtained by core needle biopsy may have a potential to be used as a complement to the current diagnostic and prognostic measures for breast cancers. PMID:22028780

Ultrasound-guided injection of botulinum toxin A in the treatment of iliopsoas spasticity

PubMed Central

Sconfienza, L.M.; Perrone, N.; Lacelli, F.; Lentino, C.; Serafini, G.

2008-01-01

Purpose Intramuscular injection of botulinum toxin A (BTX-A) is a common treatment for iliopsoas muscle spasticity, but it is not easy to position the needle in this muscle without guidance. In this paper we describe an ultrasound-guided technique for the intramuscular injection of BTX-A to treat spasticity of the iliopsoas muscle. Its effectiveness was assessed in 10 patients. Method and materials The ultrasound-guided technique for BTX-A injection was used on 10 patients. The needle was inserted into the muscle belly at an angle of 45° along the longitudinal axis of the muscle when allowed by patient's condition. Results In all cases, the iliopsoas muscle was easily identified and both the iliac and psoas components were assessed. Introduction of the needle and drug injection were entirely carried out under ultrasonographic guidance. The procedure was successful in all patients, even in those with a high-grade spasticity, and general anesthesia was not required. Conclusions This ultrasound-guided technique allows accurate guidance for the injection of BTX-A, and it can be considered as an alternate supportive therapy in patients with spasticity and dystonia. PMID:23396653

Frequency-tuning input-shaped manifold-based switching control for underactuated space robot equipped with flexible appendages

NASA Astrophysics Data System (ADS)

Kojima, Hirohisa; Ieda, Shoko; Kasai, Shinya

2014-08-01

Underactuated control problems, such as the control of a space robot without actuators on the main body, have been widely investigated. However, few studies have examined attitude control problems of underactuated space robots equipped with a flexible appendage, such as solar panels. In order to suppress vibration in flexible appendages, a zero-vibration input-shaping technique was applied to the link motion of an underactuated planar space robot. However, because the vibrational frequency depends on the link angles, simple input-shaping control methods cannot sufficiently suppress the vibration. In this paper, the dependency of the vibrational frequency on the link angles is measured experimentally, and the time-delay interval of the input shaper is then tuned based on the frequency estimated from the link angles. The proposed control method is referred to as frequency-tuning input-shaped manifold-based switching control (frequency-tuning IS-MBSC). The experimental results reveal that frequency-tuning IS-MBSC is capable of controlling the link angles and the main body attitude to maintain the target angles and that the vibration suppression performance of the proposed frequency-tuning IS-MBSC is better than that of a non-tuning IS-MBSC, which does not take the frequency variation into consideration.

Influence of long-term chronic exposure and weather conditions on Scots pine populations.

PubMed

Geras'kin, Stanislav; Vasiliyev, Denis; Makarenko, Ekaterina; Volkova, Polina; Kuzmenkov, Alexey

2017-04-01

Over a period of 8 years (2007-2014), we were evaluating seed quality and morphological abnormalities in Scots pine trees affected as a result of the Chernobyl accident. The calculated dose rates for the trees at the study sites varied from background values at the reference sites to 40 mGy/year at the most contaminated site. We investigated whether radioactive contamination and/or weather factors could decrease the reproductive capacity or increase the frequency of morphological abnormalities of needles in pine trees. Scots pine seeds are characterized by high interannual variability of viability, which is largely determined by weather conditions. No consistent differences in reproductive capacity were detected between the impacted and reference populations. Brachyblasts with three needles were found only in the affected populations; however, their frequency was very low and only at the very border of significance at the p < 0.10 level.

Contactless microparticle control via ultrahigh frequency needle type single beam acoustic tweezers

NASA Astrophysics Data System (ADS)

Fei, Chunlong; Li, Ying; Zhu, Benpeng; Chiu, Chi Tat; Chen, Zeyu; Li, Di; Yang, Yintang; Kirk Shung, K.; Zhou, Qifa

2016-10-01

This paper reports on contactless microparticle manipulation including single-particle controlled trapping, transportation, and patterning via single beam acoustic radiation forces. As the core component of single beam acoustic tweezers, a needle type ultrasonic transducer was designed and fabricated with center frequency higher than 300 MHz and -6 dB fractional bandwidth as large as 64%. The transducer was built for an f-number close to 1.0, and the desired focal depth was achieved by press-focusing technology. Its lateral resolution was measured to be better than 6.7 μm by scanning a 4 μm tungsten wire target. Tightly focused acoustic beam produced by the transducer was shown to be capable of manipulating individual microspheres as small as 3 μm. "USC" patterning with 15 μm microspheres was demonstrated without affecting nearby microspheres. These promising results may expand the applications in biomedical and biophysical research of single beam acoustic tweezers.

Can a fake fir tell the truth about Swiss needle cast? (paper) ...

EPA Pesticide Factsheets

A key question in dendrochronology to reconstruct forest disturbance history is how to distinguish between the effects of Swiss needle cast (SNC) and other forest disturbance agents (e.g., Arceuthobium spp., Armillaria, Phaseolus schweinitzii, Dendroctonus ponderosae, Dendroctonus pseudotsugae, Choristoneura occidentalis Freeman, Orgyia pseudotsugata McDunnough) on radial stem growth of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). SNC impacts physiological processes of carbon and water relations by stomatal occlusion and early needle abscission resulting in a reduction of tree growth with a distinct periodicity, whereas phytophagous pests reduce tree growth by defoliation with epidemics following less regular pseudo-periodicities. Outbreaks of the various forest disturbance agents differ in their magnitude, frequency, and duration. In particular, SNC impacts on Douglas-fir growth display a primary periodicity of 6-30 years and a secondary periodicity of 3-5 years which is unique to the causal fungus Phaeocryptopus gaeumannii (Rhode) Petrak. We use frequency domain analysis of tree-ring chronologies of Douglas-fir to identify the SNC disease cycle and separate the confounding effects of climate and SNC. We demonstrate the dendroecological reconstruction of SNC impacts on ancient Douglas-fir trees dated ~65K radioactive years B.P. from Eddyville, OR that were unearthed by the Oregon Department of Transportation. By the end of the 21st century, climate

Needle detection in ultrasound using the spectral properties of the displacement field: a feasibility study

NASA Astrophysics Data System (ADS)

Beigi, Parmida; Salcudean, Tim; Rohling, Robert; Lessoway, Victoria A.; Ng, Gary C.

2015-03-01

This paper presents a new needle detection technique for ultrasound guided interventions based on the spectral properties of small displacements arising from hand tremour or intentional motion. In a block-based approach, the displacement map is computed for each block of interest versus a reference frame, using an optical flow technique. To compute the flow parameters, the Lucas-Kanade approach is used in a multiresolution and regularized form. A least-squares fit is used to estimate the flow parameters from the overdetermined system of spatial and temporal gradients. Lateral and axial components of the displacement are obtained for each block of interest at consecutive frames. Magnitude-squared spectral coherency is derived between the median displacements of the reference block and each block of interest, to determine the spectral correlation. In vivo images were obtained from the tissue near the abdominal aorta to capture the extreme intrinsic body motion and insertion images were captured from a tissue-mimicking agar phantom. According to the analysis, both the involuntary and intentional movement of the needle produces coherent displacement with respect to a reference window near the insertion site. Intrinsic body motion also produces coherent displacement with respect to a reference window in the tissue; however, the coherency spectra of intrinsic and needle motion are distinguishable spectrally. Blocks with high spectral coherency at high frequencies are selected, estimating a channel for needle trajectory. The needle trajectory is detected from locally thresholded absolute displacement map within the initial estimate. Experimental results show the RMS localization accuracy of 1:0 mm, 0:7 mm, and 0:5 mm for hand tremour, vibrational and rotational needle movements, respectively.

Reconfigurable wavefront sensor for ultrashort pulses.

PubMed

Bock, Martin; Das, Susanta Kumar; Fischer, Carsten; Diehl, Michael; Börner, Peter; Grunwald, Ruediger

2012-04-01

A highly flexible Shack-Hartmann wavefront sensor for ultrashort pulse diagnostics is presented. The temporal system performance is studied in detail. Reflective operation is enabled by programming tilt-tolerant microaxicons into a liquid-crystal-on-silicon spatial light modulator. Nearly undistorted pulse transfer is obtained by generating nondiffracting needle beams as subbeams. Reproducible wavefront analysis and spatially resolved second-order autocorrelation are demonstrated at incident angles up to 50° and pulse durations down to 6 fs.

Devitrite-based optical diffusers.

PubMed

Butt, Haider; Knowles, Kevin M; Montelongo, Yunuen; Amaratunga, Gehan A J; Wilkinson, Timothy D

2014-03-25

Devitrite is a novel material produced by heat treatment of commercial soda-lime-silica glass. It consists of fans of needle-like crystals which can extend up to several millimeters and have interspacings of up to a few hundred nanometers. To date, only the material properties of devitrite have been reported, and there has been a distinct lack of research on using it for optical applications. In this study, we demonstrate that randomly oriented fans of devitrite crystals can act as highly efficient diffusers for visible light. Devitrite crystals produce phase modulation of light because of their relatively high anisotropy. The nanoscale spacings between these needles enable light to be diffused to large scattering angles. Experimentally measured results suggest that light diffusion patterns with beam widths of up to 120° are produced. Since devitrite is an inexpensive material to produce, it has the potential to be used in a variety of commercial applications.

Synthesis and synchrotron characterisation of novel dual-template of hydroxyapatite scaffolds with controlled size porous distribution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lima, Thiago A. R. M.; Ilavsky, Jan; Hammons, Joshua

Hydroxyapatite (HAP) scaffolds with a hierarchical porous architecture were prepared by a new dual-template (corn starch and cetyltrimethylammonium bromide (CTAB) surfactant) used to cast HAP nanoparticles and development scaffolds with size hierarchical porous distribution. The Powder X-Ray diffraction (XRD) results showed that only the HAP crystalline phase is present in the samples after calcination; the Scanning Electron Microscopy (SEM) combined with Small Angle (SAXS) and Ultra-Small Angle X-ray Scattering (USAXS) techniques showed that the porous arrangement is promoted by needle-like HAP nanoparticles, and that the pore size distributions depend on the drip-order of the calcium and the phosphate solutions duringmore » the template preparation stage.« less

Full Angle Spatial Compound of ARFI images for breast cancer detection.

PubMed

González-Salido, Nuria; Medina, Luis; Camacho, Jorge

2016-09-01

Automated ultrasound breast imaging would overcome most of the limitations that precludes conventional hand-held echography to be an effective screening method for breast cancer diagnosis. If a three dimensional (3D) ultrasound dataset is acquired without manual intervention of the technician, repeatability and patient follow-up could be improved. Furthermore, depending on the system configuration, resolution and contrast could be enhanced with regard to conventional echography, improving lesion detectability and evaluation. Having multiple modalities is another major advantage of these automated systems, currently under development by several research groups. Because of their circular structure, some of them include through-transmission measurements that allow constructing speed of sound and attenuation maps, which adds complementary information to the conventional reflectivity B-Mode image. This work addresses the implementation of the Acoustic Radiation Force Impulse (ARFI) imaging technique in a Full Angle Spatial Compound (FASC) automated breast imaging system. It is of particular interest because of the high specificity of ARFI for breast cancer diagnosis, by representing tissue elasticity differences rather than acoustic reflectivity. First, the image formation process is analyzed and a compounding strategy is proposed for ARFI-FASC. Then, experimental results with a prototype system and two gelatin phantoms are presented: Phantom A with a hard inclusion in a soft background, and phantom B with three soft inclusions in a hard background and with three steel needles. It is demonstrated that the full angle composition of ARFI images improves image quality, enhancing Contrast to Noise Ratio (CNR) from 4.9 to 20.6 and 3.6 to 13.5 in phantoms A and B respectively. Furthermore, this CNR increase improved detectability of small structures (needles) with regard to images obtained from a single location, in which image texture masked their presence. Copyright © 2016 Elsevier B.V. All rights reserved.

Pinus Monophylla (Single Needled Pinyon Pine) show morphological changes in needle cell size and stomata over the past 100 years of rising CO2 in Western Arid Ecosystems.

NASA Astrophysics Data System (ADS)

Van De Water, P. K.

2016-12-01

The size, frequency, and morphology of leaf surface stomata is used to reconstruct past levels of atmospheric carbon dioxide over geologic time. This technique relies on measuring cell and cell-clusters to correlate with changes of known carbon dioxide levels in the atmosphere. Unfortunately, not all plants are suitable because the occurrence and placement of stomatal cell-complexes differ significantly between plant families. Monocot and dicot angiosperms exhibit different types of stomata and stomatal complexes that lack order and thus are unsuitable. But, in gymnosperms, the number and distribution of stomata and pavement cells is formalized and can be used to reconstruct past atmospheric carbon dioxide levels. However, characteristic of each plant species must still be considered. For example, conifers are useful but are divided into two-needle to five-needle pines, or have irregular surface morphology (Pseudotsuga sp. and Tsuga sp. needles). This study uses Pinus monophylla an undivided needle morphology, that being a cylinder has no interior surface cells. Pinus monophylla (single needle pinyon) needles were collected along Geiger Grade (Nevada State Highway 341, Reno) in 2005 and 2013 from 1500m to 2195m. Herbarium samples were also collected from 13 historic collections made between 1911 and 1994. The study determined changes with elevation and/or over time using in these populations. Using Pinus monophylla, insured needles represented a single surface with stomata, stomatal complex cells, and co-occurring pavement cell types. Results show decreased stomatal densities (stomata/area), stomatal index (stomata/stomata + epidermal cells) and stable stomata per row (stomata/row) . Epidermal cell density (Epidermal Cells /Area), and Pavement cell density (Pavement cell/area) track stomatal density similarly. Data comparison, using elevation in the 2005 and 2013 collections showed no-significant trends. Individual stomatal complexes show no differences in the size and shape over time or with elevation. Stomata morphology and the stomatal pores appear conservative. However some complex cells show a morphology suggesting they are not fully formed and functional. These characteristics appear often in the modern material suggesting some stomata never fully develop.

Frequency-dependent changes in sensorimotor and pain affective systems induced by empathy for pain

PubMed Central

Motoyama, Yoshimasa; Ogata, Katsuya; Hoka, Sumio; Tobimatsu, Shozo

2017-01-01

Background Empathy for pain helps us to understand the pain of others indirectly. To better comprehend the processing of empathic pain, we report the frequency-dependent modulation of cortical oscillations induced by watching movies depicting pain using high-density electroencephalography (EEG), magnetoencephalography (MEG), and motor evoked potentials (MEP). Methods Event-related desynchronization of EEG and MEG was assessed while participants viewed videos of painful (needle) or neutral (cotton swab) situations. The amplitudes of MEPs were also compared between the needle and cotton swab conditions. Results The degree of suppression in α/β band power was significantly increased, whereas that of γ band power was significantly decreased, in the needle condition compared with the cotton swab condition. EEG revealed that significant differences in α/β band were distributed in the right frontocentral and left parietooccipital regions, whereas significant γ band differences were distributed predominantly over the right hemisphere, which were confirmed by source estimation using MEG. There was a significant positive correlation between the difference in γ power of the two conditions and the visual analog scale subjective rating of aversion, but not in the α/β band. The amplitude of MEPs decreased in the needle condition, which confirmed the inhibition of the primary motor cortex. Conclusion MEP suppression supports that modulation of cortical oscillations by viewing movies depicting pain involves sensorimotor processing. Our results suggest that α/β oscillations underlie the sensory qualities of others’ pain, whereas the γ band reflects the cognitive aspect. Therefore, α/β and γ band oscillations are differentially involved in empathic pain processing under the condition of motor cortical suppression. PMID:28615963

Electrical and optical characteristics of atmospheric pressure plasma needle jet driven by neon trasformer

NASA Astrophysics Data System (ADS)

Elfa, Rizan Rizon; Ahmad, Mohd Khairul; Soon, Chin Fhong; Sahdan, Mohd Zainizan; Lias, Jais; Mamat, Mohamad Hafiz; Rusop, Mohamad; Nayan, Nafarizal

2017-09-01

The atmospheric pressure plasma needle jet driven by double sinusoidal waveform of neon transformer is reported in this paper. The commercial neon transformer produces about 5 kV of peak sinusoidal voltages and 35 kHz of frequency. Argon gas has been used as discharge gas for this system since the discharge was easily developed rather than using helium gas. In addition, argon gas is three times cheaper than helium gas. The electrical property of the argon discharge has been analyzed in details by measuring its voltage, current and power during the discharge process. Interestingly, it has been found that the total power on the inner needle electrode was slightly lower than that of outer electrode. This may be due to the polarization charges that occurred at inner needle electrode. Then, further investigation to understand the discharge properties was carried out using optical emission spectroscopy (OES) analysis. During OES measurements, two positions of plasma discharge are measured by aligning the quartz optical lens and spectrometer fiber. The OH emission intensity was found higher than that of N2 at the plasma orifice. However, OH emission intensity was lower at 1.5 cm distance from orifice which may be due to penning ionization effect. These results and understanding are essential for surface modification and biomedical applications of atmospheric pressure plasma needle jet.

Genotoxicity of dill (Anethum graveolens L.), peppermint (Menthaxpiperita L.) and pine (Pinus sylvestris L.) essential oils in human lymphocytes and Drosophila melanogaster.

PubMed

Lazutka, J R; Mierauskiene, J; Slapsyte, G; Dedonyte, V

2001-05-01

Genotoxic properties of the essential oils extracted from dill (Anethum graveolens L.) herb and seeds, peppermint (Menthaxpiperita L.) herb and pine (Pinus sylvestris L.) needles were studied using chromosome aberration (CA) and sister chromatid exchange (SCE) tests in human lymphocytes in vitro, and Drosophila melanogaster somatic mutation and recombination test (SMART) in vivo. In the CA test, the most active essential oil was from dill seeds, then followed essential oils from dill herb, peppermint herb and pine needles, respectively. In the SCE test, the most active essential oils were from dill herb and seeds followed by essential oils from pine needles and peppermint herb. Essential oils from dill herb and seeds and pine needles induced CA and SCE in a clear dose-dependent manner, while peppermint essential oil induced SCE in a dose-independent manner. All essential oils were cytotoxic for human lymphocytes. In the SMART test, a dose-dependent increase in mutation frequency was observed for essential oils from pine and dill herb. Peppermint essential oil induced mutations in a dose-independent manner. Essential oil from dill seeds was almost inactive in the SMART test.

Favourable Outcomes of Endovascular Total Aortic Arch Repair Via Needle Based In Situ Fenestration at a Mean Follow-Up of 5.4 Months.

PubMed

Shang, Tao; Tian, Lu; Li, Dong-Lin; Wu, Zi-Heng; Zhang, Hong-Kun

2018-03-01

Endovascular repair of aortic arch pathologies remains challenging. Recently, needle based in situ fenestration (ISF) has shown great potential in endovascular total aortic arch repair (ETAAR). This study aimed to evaluate the feasibility, effectiveness, and safety of ETAAR via needle based ISF, and to present initial experience with this technique. Patients who met the inclusion criteria were enrolled in this prospective study. The supra-arch branches were manually punctured in a retrograde manner using liver biopsy needles (18 gauge/30 cm) in the left common carotid artery (LCCA) and brachiocephalic trunk (BCT), and endo-puncture system or aspiration biopsy needles (21-gauge) in the left subclavian artery (LSA). All the branches were revascularised with bridge stents. Routine follow-up occurred at 1, 3, 6, and 12 months post surgery. Ten patients with arch pathologies underwent ETAAR. Revascularisation of three branches was successfully performed in eight patients, but attempts to create ISF in LSA were unsuccessful in two patients because of tortuosity and sharp angle. The time taken to establish ISF in LCCA and BCT was 100.4s and 489.6s, respectively. Bilateral regional cerebral oxygen saturation (RCOS) decreased after the arch endograft deployment (both, p < .001) and recovered to the pre-operative level once both carotid arteries were reconstructed (left, p = .0856; right, p = .6). The right RCOS was higher with the beneficial effect of extracorporeal circulation (after cTAGs deployment, p < .001; after LCCA revascularised, p = .0148) during the ischaemic period. In one case, the left iliac artery ruptured, but no ISF related or neurological complications occurred. An early follow-up (mean 5.44 months) CTA and ultrasound confirmed patency of all the branch grafts without any endoleak or migration CONCLUSIONS: This study demonstrated that ETAAR via needle based ISF, making full use of off the shelf devices and techniques, can be successfully performed in aortic arch pathologies with a favourable early outcome. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.

SU-F-T-44: A Comparison of the Pre-Plan, Intra-Operative Plan, and Post-Implant Dosimetry for a Prostate Implant Case Using Prefabricated Linear Polymer-Encapsulated Pd-103

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheu, R; Powers, A; McGee, H

Purpose: To investigate the reproducibility and limitations of Pd-103 prostate brachytherapy using fixed length linear sources (CivaString). Methods: An LDR prostate brachytherapy case which was preplanned on MR images with prefabricated linear polymer-encapsulated Pd-103 sources (CivaString) was studied and compared with ultrasound based intra-operative planning and CT based post-implant dosimetry. We evaluated the following parameters among the three studies: prostate geometry (volume and cross sectional area), needle position and alignment deviations, and dosimetry parameters (D90). Results: The prostate volumes and axial cross sectional areas at center of prostate were measured as 41.8, 39.3 and 36.8 cc, and 14.9, 14.3, andmore » 11.3 respectively on pre-plan MR, inter-op US, and post-implant CT studies. The deviation of prostate volumes and axial cross sectional areas measured on pre-planning MR and intra-operative US were within 5%. 17 out of 19 pre-planned needles were positioned within 5mm (the template grid size). One needle location was adjusted intra-operatively and another needle was removed due to proximity to urethra. The needle pathways were not always parallel to the trans-rectal probe due to the flexibility of CivaString. The angle of deviation was up to 10 degrees. Two pairs of needles were exchanged to better fit the length of prostate at the time of implant. This resulted in a prostate D90 of 153.8 Gy (124%) and 131.4 Gy (106.7%) for intra-op and PID respectively. Conclusion: Preplanning is a necessary part of implants performed with prefabricated linear polymer sources. However, as is often the case, there were real-time deviations from the pre-plan. Intra-op planning provides the ability conform to anatomy at the time of implant. Therefore, we propose to develop a systematic way to order extra strings of different length to provide the flexibility to perform intra-operative planning with fixed length strands.« less

Exploration of assistive technology for uniform laparoscopic surgery.

PubMed

Sato, Masakazu; Koizumi, Minako; Hino, Takahiro; Takahashi, Yu; Nagashima, Natsuki; Itaoka, Nao; Ueshima, Chiharu; Nakata, Maki; Hasumi, Yoko

2018-02-19

Laparoscopic surgery is less invasive than open surgery and is now common in various medical fields. However, laparoscopic surgery is more difficult than open surgery and often requires additional time for the operator to achieve mastery. Therefore, we investigated the use of assistive technology for uniform laparoscopic surgery. We used the OpenCV2 library for augmented reality with an ArUco marker to detect and estimate forceps positioning. We used Sense HAT as the gyro sensor. The development platforms used were Mac OS X 10.11.3 and Raspberry Pi 3, model B. By attaching the ArUco marker to the needle holder, we could draw a line vertically to the marker. When the needle was held, a cube could be imagined, and both the needle and lines could be used to determine the appropriate position. By attaching the gyro sensor to the camera, we could detect its angle of rotation. We obtained stabilized images by rotating the image by the detected degrees; this was possible for any camera position. Assistive technology allowed us to obtain consecutive converted images in real time and may be readily applicable to clinical practice. © 2018 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.

A scattering model for forested area

NASA Technical Reports Server (NTRS)

Karam, M. A.; Fung, A. K.

1988-01-01

A forested area is modeled as a volume of randomly oriented and distributed disc-shaped, or needle-shaped leaves shading a distribution of branches modeled as randomly oriented finite-length, dielectric cylinders above an irregular soil surface. Since the radii of branches have a wide range of sizes, the model only requires the length of a branch to be large compared with its radius which may be any size relative to the incident wavelength. In addition, the model also assumes the thickness of a disc-shaped leaf or the radius of a needle-shaped leaf is much smaller than the electromagnetic wavelength. The scattering phase matrices for disc, needle, and cylinder are developed in terms of the scattering amplitudes of the corresponding fields which are computed by the forward scattering theorem. These quantities along with the Kirchoff scattering model for a randomly rough surface are used in the standard radiative transfer formulation to compute the backscattering coefficient. Numerical illustrations for the backscattering coefficient are given as a function of the shading factor, incidence angle, leaf orientation distribution, branch orientation distribution, and the number density of leaves. Also illustrated are the properties of the extinction coefficient as a function of leaf and branch orientation distributions. Comparisons are made with measured backscattering coefficients from forested areas reported in the literature.

Relating ground truth collection to model sensitivity

NASA Technical Reports Server (NTRS)

Amar, Faouzi; Fung, Adrian K.; Karam, Mostafa A.; Mougin, Eric

1993-01-01

The importance of collecting high quality ground truth before a SAR mission over a forested area is two fold. First, the ground truth is used in the analysis and interpretation of the measured backscattering properties; second, it helps to justify the use of a scattering model to fit the measurements. Unfortunately, ground truth is often collected based on visual assessment of what is perceived to be important without regard to the mission itself. Sites are selected based on brief surveys of large areas, and the ground truth is collected by a process of selecting and grouping different scatterers. After the fact, it may turn out that some of the relevant parameters are missing. A three-layer canopy model based on the radiative transfer equations is used to determine, before hand, the relevant parameters to be collected. Detailed analysis of the contribution to scattering and attenuation of various forest components is carried out. The goal is to identify the forest parameters which most influence the backscattering as a function of frequency (P-, L-, and C-bands) and incident angle. The influence on backscattering and attenuation of branch diameters, lengths, angular distribution, and permittivity; trunk diameters, lengths, and permittivity; and needle sizes, their angular distribution, and permittivity are studied in order to maximize the efficiency of the ground truth collection efforts. Preliminary results indicate that while a scatterer may not contribute to the total backscattering, its contribution to attenuation may be significant depending on the frequency.

Human responses to upright tilt: a window on central autonomic integration

NASA Technical Reports Server (NTRS)

Cooke, W. H.; Hoag, J. B.; Crossman, A. A.; Kuusela, T. A.; Tahvanainen, K. U.; Eckberg, D. L.

1999-01-01

1. We examined interactions between haemodynamic and autonomic neural oscillations during passive upright tilt, to gain better insight into human autonomic regulatory mechanisms. 2. We recorded the electrocardiogram, finger photoplethysmographic arterial pressure, respiration and peroneal nerve muscle sympathetic activity in nine healthy young adults. Subjects breathed in time with a metronome at 12 breaths min-1 (0.2 Hz) for 5 min each, in supine, and 20, 40, 60, 70 and 80 deg head-up positions. We performed fast Fourier transform (and autoregressive) power spectral analyses and integrated low-frequency (0.05-0.15 Hz) and respiratory-frequency (0. 15-0.5 Hz) spectral powers. 3. Integrated areas of muscle sympathetic bursts and their low- and respiratory-frequency spectral powers increased directly and significantly with the tilt angle. The centre frequency of low-frequency sympathetic oscillations was constant before and during tilt. Sympathetic bursts occurred more commonly during expiration than inspiration at low tilt angles, but occurred equally in expiration and inspiration at high tilt angles. 4. Systolic and diastolic pressures and their low- and respiratory-frequency spectral powers increased, and R-R intervals and their respiratory-frequency spectral power decreased progressively with the tilt angle. Low-frequency R-R interval spectral power did not change. 5. The cross-spectral phase angle between systolic pressures and R-R intervals remained constant and consistently negative at the low frequency, but shifted progressively from positive to negative at the respiratory frequency during tilt. The arterial baroreflex modulus, calculated from low-frequency cross-spectra, decreased at high tilt angles. 6. Our results document changes of baroreflex responses during upright tilt, which may reflect leftward movement of subjects on their arterial pressure sympathetic and vagal response relations. The intensity, but not the centre frequency of low-frequency cardiovascular rhythms, is modulated by the level of arterial baroreceptor input. Tilt reduces respiratory gating of sympathetic and vagal motoneurone responsiveness to stimulatory inputs for different reasons; during tilt, sympathetic stimulation increases to a level that overwhelms the respiratory gate, and vagal stimulation decreases to a level below that necessary for maximal respiratory gating to occur.

Human responses to upright tilt: a window on central autonomic integration.

PubMed

Cooke, W H; Hoag, J B; Crossman, A A; Kuusela, T A; Tahvanainen, K U; Eckberg, D L

1999-06-01

1. We examined interactions between haemodynamic and autonomic neural oscillations during passive upright tilt, to gain better insight into human autonomic regulatory mechanisms. 2. We recorded the electrocardiogram, finger photoplethysmographic arterial pressure, respiration and peroneal nerve muscle sympathetic activity in nine healthy young adults. Subjects breathed in time with a metronome at 12 breaths min-1 (0.2 Hz) for 5 min each, in supine, and 20, 40, 60, 70 and 80 deg head-up positions. We performed fast Fourier transform (and autoregressive) power spectral analyses and integrated low-frequency (0.05-0.15 Hz) and respiratory-frequency (0. 15-0.5 Hz) spectral powers. 3. Integrated areas of muscle sympathetic bursts and their low- and respiratory-frequency spectral powers increased directly and significantly with the tilt angle. The centre frequency of low-frequency sympathetic oscillations was constant before and during tilt. Sympathetic bursts occurred more commonly during expiration than inspiration at low tilt angles, but occurred equally in expiration and inspiration at high tilt angles. 4. Systolic and diastolic pressures and their low- and respiratory-frequency spectral powers increased, and R-R intervals and their respiratory-frequency spectral power decreased progressively with the tilt angle. Low-frequency R-R interval spectral power did not change. 5. The cross-spectral phase angle between systolic pressures and R-R intervals remained constant and consistently negative at the low frequency, but shifted progressively from positive to negative at the respiratory frequency during tilt. The arterial baroreflex modulus, calculated from low-frequency cross-spectra, decreased at high tilt angles. 6. Our results document changes of baroreflex responses during upright tilt, which may reflect leftward movement of subjects on their arterial pressure sympathetic and vagal response relations. The intensity, but not the centre frequency of low-frequency cardiovascular rhythms, is modulated by the level of arterial baroreceptor input. Tilt reduces respiratory gating of sympathetic and vagal motoneurone responsiveness to stimulatory inputs for different reasons; during tilt, sympathetic stimulation increases to a level that overwhelms the respiratory gate, and vagal stimulation decreases to a level below that necessary for maximal respiratory gating to occur.

A remarkably easy knot-tying technique for single-incision laparoscopic surgery with the SILS port for gynecologic diseases.

PubMed

Endo, Toshiaki; Nagasawa, Kunihiko; Umemura, Kota; Baba, Tsuyoshi; Henmi, Hirofumi; Saito, Tsuyoshi

2011-01-01

Single-incision laparoscopic surgery (SILS) has been quickly accepted, especially for women, because the cosmetic benefits may be greater than with ordinary laparoscopic surgery. In gynecologic disease, SILS is appropriate for diagnostic laparoscopy, oophorectomy, and salpingectomy, among other conditions. In addition, the knot-tying process for intracorporeal suturing during SILS is a major rate-limiting step and a key determinant of the popularity of SILS. Although a roticulator instrument is useful for creating the needed operative angle, knot tying is still believed to be difficult. We have devised a remarkably simple knot-tying technique that can be applied during SILS with a SILS Port with a Roticulator and a straight-type needle driver. We determined that, after transfixing the needle, the long tail of the thread should be grasped at around 90 degrees relative to the long axis of tip of the Roticulator, which is articulated at 80 degrees. This automatically forms an ideal C-loop because of gravitation. The needle attached to the long tail should face the distal side from the tip of Roticulator (from the surgeon's perspective). The apex of the C-loop is then toward the proximal side from the tip of the Roticulator (from the perspective of the surgeon). This thread position is important during the knot-tying process. The upper arm of the C-loop should then be entwined by applying a series of axial spinning movements to the rod of the needle driver. At this time, the jaws of the needle driver should be kept open so the thread does not slip off of the rod. The benefit of this technique is that it does not require any special skills; any surgeon able to perform intracorporeal suturing should also be able to easily tie knots during SILS. Copyright © 2011 AAGL. Published by Elsevier Inc. All rights reserved.

Detecting and Treating Thyroid Nodules and Cancer Before, During, and After Pregnancy

MedlinePlus

... nodules relies mainly on the results of thyroid ultrasound imaging and fine-needle aspiration biopsy . A biopsy is the removal of a small sample of the nodule for further testing. Thyroid ultrasound uses the same safe technique of high- frequency ...

Enhancement of accuracy in shape sensing of surgical needles using optical frequency domain reflectometry in optical fibers.

PubMed

Parent, Francois; Loranger, Sebastien; Mandal, Koushik Kanti; Iezzi, Victor Lambin; Lapointe, Jerome; Boisvert, Jean-Sébastien; Baiad, Mohamed Diaa; Kadoury, Samuel; Kashyap, Raman

2017-04-01

We demonstrate a novel approach to enhance the precision of surgical needle shape tracking based on distributed strain sensing using optical frequency domain reflectometry (OFDR). The precision enhancement is provided by using optical fibers with high scattering properties. Shape tracking of surgical tools using strain sensing properties of optical fibers has seen increased attention in recent years. Most of the investigations made in this field use fiber Bragg gratings (FBG), which can be used as discrete or quasi-distributed strain sensors. By using a truly distributed sensing approach (OFDR), preliminary results show that the attainable accuracy is comparable to accuracies reported in the literature using FBG sensors for tracking applications (~1mm). We propose a technique that enhanced our accuracy by 47% using UV exposed fibers, which have higher light scattering compared to un-exposed standard single mode fibers. Improving the experimental setup will enhance the accuracy provided by shape tracking using OFDR and will contribute significantly to clinical applications.

Acupuncture for melasma in women: a systematic review of randomised controlled trials.

PubMed

Chai, Qianyun; Fei, Yutong; Cao, Huijuan; Wang, Congcong; Tian, Jinzhou; Liu, Jianping

2015-08-01

Melasma is a common facial skin disorder seen in women. Manual acupuncture (MA) is widely used alone or in combination with conventional treatments for melasma in China. To assess the effectiveness and safety of MA for melasma, and explore the range of treatments applied. Six databases were searched systematically for randomised controlled trials (RCTs) on acupuncture for melasma in women up to November 2014. RevMan software was used for data analysis. The Cochrane tool of Risk of Bias was used to assess the methodological quality of the RCTs. Eight RCTs involving 587 women were included. Seven studies used the encircling needling method, four studies used the quick needling method and four studies used intensive needle manipulations. Five studies provided individualised acupuncture treatments. Points used with highest frequency were SP6, ST36 and SP10. MA was compared with oral tranexamic acid, vitamin C and E, vitamin C and tamoxifen, topical 20% azelaic acid, hydroquinone, vitamin A and no treatment. Studies were too heterogeneous to conduct a meta-analysis. For global outcome measures, seven trials showed that MA groups were significantly better than the conventional treatments either with a better cure rate or with a better combined cure rate and markedly effective rate, and one trial did not (MA vs vitamin A). No acupuncture-related adverse events were reported. MA appeared to be beneficial and safe for women with melasma, but insufficient evidence was found to reach conclusions. The encircling needling method, the quick needling method, intensive needle manipulations and individualised points' selection were widely used. Well-designed trials are required. PROSPERO Systematic review registration: CRD42013006396. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

An in vitro study of dural lesions produced by 25-gauge Quincke and Whitacre needles evaluated by scanning electron microscopy.

PubMed

Reina, M A; de Leon-Casasola, O A; Lopez, A; De Andres, J; Martin, S; Mora, M

2000-01-01

A study using scanning electron microscopy showed that although the laminas forming the dura mater are concentric and parallel to the surface of the medulla, the fiber layers' orientations are different in each sub-lamina, dispelling the conventional knowledge that all the fibers of the dura are arranged in a parallel direction. Thus, this study evaluated the dural lesions produced by Whitacre and Quincke spinal needles in the external and internal surface of the dura mater of the lower spine area in an attempt to gain more insight into the pathophysiology of postdural puncture headaches (PDPH). The T11-L4 dural membranes from 5 fresh (immediately after extraction of organs for transplantation), male patients declared brain dead, ages 23, 46, 48, 55, and 60 years, were excised by anterior laminectomy. Morphologic orientation of the membrane and normal pH were maintained with an apparatus designed for this purpose. One hundred punctures (20 on each sample) at 90-degree angles were done with a new needle each time, 50 with 25-gauge Whitacre and 50 with 25-gauge Quincke needles. Half of the punctures with the Quincke needles were done with the bevel in parallel direction to the axis of the spinal cord, and the rest with the bevel perpendicular to it. Fixation in solutions of 2.5% glutaraldehyde phosphate buffer, followed by dehydration with acetone, was done 15 minutes after the punctures. After acetone was removed at ideal conditions of temperature and pressure, the specimens were then metallized with carbon followed by gold and inspected under a scanning electron microscope. Twenty-five of the Whitacre and 23 of the Quincke punctures were found for evaluation. There were no differences in the cross-sectional area of the punctures produced by the Whitacre or Quincke needles on the dura. The area of the dural lesions produced by 25-gauge Quincke needles, 15 minutes after they have been withdrawn, was 0.023 mm2 (confidence interval [CI] 95%, 0.015 to 0.027) in the external aspect (epidural surface) and 0.034 mm2 (CI 95%, 0.018 to 0.051) in the internal aspect (arachnoid surface) of the dural sac. The area of the lesions produced by the 25-gauge Whitacre needles was 0.026 mm2 (CI 95%, 0.019 to 0.032) and 0.030 mm2 (CI 95%, 0.025 to 0.036) in the external and internal surfaces of the dural sac, respectively. There were no significant differences in the cross-sectional areas of the punctures produced by the 25-gauge Whitacre or 25-gauge Quincke needles. Moreover, with Quincke needles the dural lesions closed in an 88.3% (CI 95%, 86.3 to 92.4) and 82.7% (CI 95%, 74.1 to 90.9) of their original sizes in the epidural and arachnoid surfaces, respectively. With Whitacre needles, the closure occurred in an 86.8% (CI 95%, 83.8 to 90.3) and 84.8% (CI 95% 81.7 to 87.3) in the dural and arachnoid surfaces, respectively. However, there were differences in the morphology of the lesions. The Whitacre needles produced coarse lesions with significant destruction in the dura's fibers while the Quincke needles produced a 'U'-shaped lesion (flap) that mimics the opened lid of a tin can, regardless of the tip's direction. The needles produced lesions in the dura with different morphology and characteristics. Lesions with the Quincke needles resulted in a clean-cut opening in the dural membrane while the Whitacre needle produced a more traumatic opening with tearing and severe disruption of the collagen fibers. Thus, we hypothesized that the lower incidence of PDPH seen with the Whitacre needles may be explained, in part, by the inflammatory reaction produced by the tearing of the collagen fibers after dural penetration. This inflammatory reaction may result in a significant edema which may act as a plug limiting the leakage of cerebrospinal fluid.

The Postdural Puncture Headache and Back Pain: The Comparison of 26-gauge Atraucan and 26-gauge Quincke Spinal Needles in Obstetric Patients.

PubMed

Akdemir, Mehmet Salim; Kaydu, Ayhan; Yanlı, Yonca; Özdemir, Mehtap; Gökçek, Erhan; Karaman, Haktan

2017-01-01

The postdural puncture headache (PDPH) and postdural puncture backache (PDPB) are well-known complications of spinal anesthesia. There are some attempts to reduce the frequency of complication such as different design of the spinal needles. The primary outcome of this study is to compare the incidence of PDPH between 26-gauge Atraucan and 26-gauge Quincke spinal needles in elective cesarean operations. The severity of symptoms, the incidence of backache, technical issues, and comparison of cost of needles are secondary outcomes. After Investigational Review Board approval, a randomized, prospective, double-blinded study was designed in 682 American Society of Anesthesiologists I-II women having elective cesarean operations under spinal anesthesia. Patients were divided into two groups as 26-gauge Atraucan Group A ( n = 323) and 26-gauge Quincke spinal needles Group Q ( n = 342). All patients were questioned about backache 1 week later. Differences between categorical variables were evaluated with Chi-square test. Continuous variables were compared by Student's t -test for two independent groups. A two-sided P < 0.05 was considered statistically significant for all analyses. There were no significant differences between groups in all demographic data. The one attempt success rate of the dural puncture in Group A (70,58%) and in Group Q (69.3%) was similar ( P > 0.05). The incidence of PDPH was 6.5% in Group A and 4.9% in Group Q ( P > 0.05). The epidural blood patch was performed to the three patients in Group A and five patients in Group Q who had severe headache ( P > 0.05). The incidence of PDPB was 4.33% versus 2.04% in Group A and Group Q ( P > 0.05). The incidence of complication rates and technical handling characteristics did not differ between two groups. Quincke needle is cheaper than Atracaun needle, so it can be a cost-effective choice in obstetric patients.

The Postdural Puncture Headache and Back Pain: The Comparison of 26-gauge Atraucan and 26-gauge Quincke Spinal Needles in Obstetric Patients

PubMed Central

Akdemir, Mehmet Salim; Kaydu, Ayhan; Yanlı, Yonca; Özdemir, Mehtap; Gökçek, Erhan; Karaman, Haktan

2017-01-01

Background: The postdural puncture headache (PDPH) and postdural puncture backache (PDPB) are well-known complications of spinal anesthesia. There are some attempts to reduce the frequency of complication such as different design of the spinal needles. Aims: The primary outcome of this study is to compare the incidence of PDPH between 26-gauge Atraucan and 26-gauge Quincke spinal needles in elective cesarean operations. The severity of symptoms, the incidence of backache, technical issues, and comparison of cost of needles are secondary outcomes. Materials and Methods: After Investigational Review Board approval, a randomized, prospective, double-blinded study was designed in 682 American Society of Anesthesiologists I–II women having elective cesarean operations under spinal anesthesia. Patients were divided into two groups as 26-gauge Atraucan Group A (n = 323) and 26-gauge Quincke spinal needles Group Q (n = 342). All patients were questioned about backache 1 week later. Differences between categorical variables were evaluated with Chi-square test. Continuous variables were compared by Student's t-test for two independent groups. A two-sided P < 0.05 was considered statistically significant for all analyses. Results: There were no significant differences between groups in all demographic data. The one attempt success rate of the dural puncture in Group A (70,58%) and in Group Q (69.3%) was similar (P > 0.05). The incidence of PDPH was 6.5% in Group A and 4.9% in Group Q (P > 0.05). The epidural blood patch was performed to the three patients in Group A and five patients in Group Q who had severe headache (P > 0.05). The incidence of PDPB was 4.33% versus 2.04% in Group A and Group Q (P > 0.05). Conclusions: The incidence of complication rates and technical handling characteristics did not differ between two groups. Quincke needle is cheaper than Atracaun needle, so it can be a cost-effective choice in obstetric patients. PMID:28663641

Three-Dimensional Ultrasound-Guided Real-Time Midline Epidural Needle Placement with Epiguide: A Prospective Feasibility Study.

PubMed

Beigi, Parmida; Malenfant, Paul; Rasoulian, Abtin; Rohling, Robert; Dube, Alison; Gunka, Vit

2017-01-01

Current 2-D ultrasound technology is unable to perform a midline neuraxial needle insertion under real-time ultrasound guidance using a standard needle and without an assistant. The aim of the work described here was to determine the feasibility of a new technology providing such capability, starting with a study evaluating the selected puncture site. A novel 3-D ultrasound imaging technique was designed using thick-slice rendering in conjunction with a custom needle guide (3DUS + Epiguide). A clinical feasibility study evaluated the ability of 3DUS + Epiguide to identify the epidural needle puncture site for a midline insertion in the lumbar spine. We hypothesized that (i) the puncture site identified by 3DUS + Epiguide was within a 5-mm radius from the site chosen by standard palpation, and (ii) the difference between the two puncture sites was not correlated to the patient characteristics age, weight, height, body mass index and gestational age. The mean (±standard deviation) distances between puncture sites determined by 3DUS + Epiguide and palpation were 3.1 (±1.7) mm and 2.8 (±1.3) mm, for the L2-3 and L3-4 interspaces of 20 patients, respectively. Distances were comparable to intra-observer variability, indicating the potential for a thick-slice rendering of 3-D ultrasound along the Epiguide trajectory to select the puncture site of a midline neuraxial needle insertion. The long-term potential benefits of this system include increased efficiency and use of anesthesia, and a reduction in the frequency and severity of the complications from incorrect needle insertions. Epidural success in the most difficult cases (e.g., the obese) will be the focus of future work. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Method for high resolution magnetic resonance analysis using magic angle technique

DOEpatents

Wind, Robert A.; Hu, Jian Zhi

2003-12-30

A method of performing a magnetic resonance analysis of a biological object that includes placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.

Method for high resolution magnetic resonance analysis using magic angle technique

DOEpatents

Wind, Robert A.; Hu, Jian Zhi

2004-12-28

A method of performing a magnetic resonance analysis of a biological object that includes placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.

Tunable angle absorption of hyperbolic metamaterials based on plasma photonic crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiao, Zheng; Ning, Renxia, E-mail: nrxxiner@hsu.edu.cn; Xu, Yuan

2016-06-15

We present the design of a multilayer structure of hyperbolic metamaterials based on plasma photonic crystals which composed of two kinds of traditional dielectric and plasma. The relative permittivity of hyperbolic metamaterials has been studied at certain frequency range. The absorption and reflection of the multilayer period structure at normal and oblique incident have been investigated by the transfer matrix method. We discussed that the absorption is affected by the thickness of material and the electron collision frequency γ of the plasma. The results show that an absorption band at the low frequency can be obtained at normal incident anglemore » and another absorption band at the high frequency can be found at a large incident angle. The results may be applied by logical gate, stealth, tunable angle absorber, and large angle filter.« less

Noncontact viscoelastic measurement of polymer thin films in a liquid medium using a long-needle AFM

NASA Astrophysics Data System (ADS)

Guan, Dongshi; Barraud, Chloe; Charlaix, Elisabeth; Tong, Penger

We report noncontact measurement of the viscoelastic property of polymer thin films in a liquid medium using frequency-modulation atomic force microscopy (FM-AFM) with a newly developed long-needle probe. The probe contains a long vertical glass fiber with one end adhered to a cantilever beam and the other end with a sharp tip placed near the liquid-film interface. The nanoscale flow generated by the resonant oscillation of the needle tip provides a precise hydrodynamic force acting on the soft surface of the thin film. By accurately measuring the mechanical response of the thin film, we obtain the elastic and loss moduli of the thin film using the linear response theory of elasto-hydrodynamics. The experiment verifies the theory and demonstrates its applications. The technique can be used to accurately measure the viscoelastic property of soft surfaces, such as those made of polymers, nano-bubbles, live cells and tissues. This work was supported by the Research Grants Council of Hong Kong SAR.

Comparison of Three Plasma Sources for Ambient Desorption/Ionization Mass Spectrometry

NASA Astrophysics Data System (ADS)

McKay, Kirsty; Salter, Tara L.; Bowfield, Andrew; Walsh, James L.; Gilmore, Ian S.; Bradley, James W.

2014-09-01

Plasma-based desorption/ionization sources are an important ionization technique for ambient surface analysis mass spectrometry. In this paper, we compare and contrast three competing plasma based desorption/ionization sources: a radio-frequency (rf) plasma needle, a dielectric barrier plasma jet, and a low-temperature plasma probe. The ambient composition of the three sources and their effectiveness at analyzing a range of pharmaceuticals and polymers were assessed. Results show that the background mass spectrum of each source was dominated by air species, with the rf needle producing a richer ion spectrum consisting mainly of ionized water clusters. It was also seen that each source produced different ion fragments of the analytes under investigation: this is thought to be due to different substrate heating, different ion transport mechanisms, and different electric field orientations. The rf needle was found to fragment the analytes least and as a result it was able to detect larger polymer ions than the other sources.

Comparison of three plasma sources for ambient desorption/ionization mass spectrometry.

PubMed

McKay, Kirsty; Salter, Tara L; Bowfield, Andrew; Walsh, James L; Gilmore, Ian S; Bradley, James W

2014-09-01

Plasma-based desorption/ionization sources are an important ionization technique for ambient surface analysis mass spectrometry. In this paper, we compare and contrast three competing plasma based desorption/ionization sources: a radio-frequency (rf) plasma needle, a dielectric barrier plasma jet, and a low-temperature plasma probe. The ambient composition of the three sources and their effectiveness at analyzing a range of pharmaceuticals and polymers were assessed. Results show that the background mass spectrum of each source was dominated by air species, with the rf needle producing a richer ion spectrum consisting mainly of ionized water clusters. It was also seen that each source produced different ion fragments of the analytes under investigation: this is thought to be due to different substrate heating, different ion transport mechanisms, and different electric field orientations. The rf needle was found to fragment the analytes least and as a result it was able to detect larger polymer ions than the other sources.

Characterization of string cavitation in large-scale Diesel nozzles with tapered holes

NASA Astrophysics Data System (ADS)

Gavaises, M.; Andriotis, A.; Papoulias, D.; Mitroglou, N.; Theodorakakos, A.

2009-05-01

The cavitation structures formed inside enlarged transparent replicas of tapered Diesel valve covered orifice nozzles have been characterized using high speed imaging visualization. Cavitation images obtained at fixed needle lift and flow rate conditions have revealed that although the conical shape of the converging tapered holes suppresses the formation of geometric cavitation, forming at the entry to the cylindrical injection hole, string cavitation has been found to prevail, particularly at low needle lifts. Computational fluid dynamics simulations have shown that cavitation strings appear in areas where large-scale vortices develop. The vortical structures are mainly formed upstream of the injection holes due to the nonuniform flow distribution and persist also inside them. Cavitation strings have been frequently observed to link adjacent holes while inspection of identical real-size injectors has revealed cavitation erosion sites in the area of string cavitation development. Image postprocessing has allowed estimation of their frequency of appearance, lifetime, and size along the injection hole length, as function of cavitation and Reynolds numbers and needle lift.

Method for high resolution magnetic resonance analysis using magic angle technique

DOEpatents

Wind, Robert A.; Hu, Jian Zhi

2003-11-25

A method of performing a magnetic resonance analysis of a biological object that includes placing the biological object in a main magnetic field and in a radio frequency field, the main magnetic field having a static field direction; rotating the biological object at a rotational frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. According to another embodiment, the radio frequency is pulsed to provide a sequence capable of producing a spectrum that is substantially free of spinning sideband peaks.

High-fidelity numerical simulation of the flow field around a NACA-0012 aerofoil from the laminar separation bubble to a full stall

NASA Astrophysics Data System (ADS)

ElJack, Eltayeb

2017-05-01

In the present work, large eddy simulations of the flow field around a NACA-0012 aerofoil near stall conditions are performed at a Reynolds number of 5 × 104, Mach number of 0.4, and at various angles of attack. The results show the following: at relatively low angles of attack, the bubble is present and intact; at moderate angles of attack, the laminar separation bubble bursts and generates a global low-frequency flow oscillation; and at relatively high angles of attack, the laminar separation bubble becomes an open bubble that leads the aerofoil into a full stall. Time histories of the aerodynamic coefficients showed that the low-frequency oscillation phenomenon and its associated physics are indeed captured in the simulations. The aerodynamic coefficients compared to previous and recent experimental data with acceptable accuracy. Spectral analysis identified a dominant low-frequency mode featuring the periodic separation and reattachment of the flow field. At angles of attack α ≤ 9.3°, the low-frequency mode featured bubble shedding rather than bubble bursting and reformation. The underlying mechanism behind the quasi-periodic self-sustained low-frequency flow oscillation is discussed in detail.

Backscattering analysis of high frequency ultrasonic imaging for ultrasound-guided breast biopsy

NASA Astrophysics Data System (ADS)

Cummins, Thomas; Akiyama, Takahiro; Lee, Changyang; Martin, Sue E.; Shung, K. Kirk

2017-03-01

A new ultrasound-guided breast biopsy technique is proposed. The technique utilizes conventional ultrasound guidance coupled with a high frequency embedded ultrasound array located within the biopsy needle to improve the accuracy in breast cancer diagnosis.1 The array within the needle is intended to be used to detect micro- calcifications indicative of early breast cancers such as ductal carcinoma in situ (DCIS). Backscattering analysis has the potential to characterize tissues to improve localization of lesions. This paper describes initial results of the application of backscattering analysis of breast biopsy tissue specimens and shows the usefulness of high frequency ultrasound for the new biopsy related technique. Ultrasound echoes of ex-vivo breast biopsy tissue specimens were acquired by using a single-element transducer with a bandwidth from 41 MHz to 88 MHz utilizing a UBM methodology, and the backscattering coefficients were calculated. These values as well as B-mode image data were mapped in 2D and matched with each pathology image for the identification of tissue type for the comparison to the pathology images corresponding to each plane. Microcalcifications were significantly distinguished from normal tissue. Adenocarcinoma was also successfully differentiated from adipose tissue. These results indicate that backscattering analysis is able to quantitatively distinguish tissues into normal and abnormal, which should help radiologists locate abnormal areas during the proposed ultrasound-guided breast biopsy with high frequency ultrasound.

Powerful actuation of magnetized microtools by focused magnetic field for particle sorting in a chip.

PubMed

Yamanishi, Yoko; Sakuma, Shinya; Onda, Kazuhisa; Arai, Fumihito

2010-08-01

This paper describes a novel powerful noncontact actuation of a magnetically driven microtool (MMT), achieved by magnetization of the MMT and focusing of the magnetic field in a microfluidic chip for particle sorting. The following are the highlights of this study: (1) an MMT was successfully fabricated from a mixture of neodymium powder and polydimethylsiloxane; the MMT was magnetized such that it acted as an elastic micromagnet with a magnetic flux density that increased by about 100 times after magnetization, and (2) a pair of sharp magnetic needles was fabricated adjacent to a microchannel in a chip by electroplating, in order to focus the magnetic flux density generated by the electromagnetic coils below the biochip; these needles contribute to miniaturization of an actuation module that would enable the integration of multiple functions in the limited area of a chip. FEM analysis of the magnetic flux density around the MMT showed that the magnetic flux density in the setup with the magnetic needles was around 8 times better than that in the setup without the needles. By magnetization, the drive frequency of the MMT improved by about 10 times--from 18 Hz to 180 Hz. We successfully demonstrated the separation of copolymer beads of a particular size in a chip by image sensing.

Efficacy of femtosecond lasers for application of acupuncture therapy.

PubMed

Ohta, Mika; Hosokawa, Yoichiroh; Hatano, Naoya; Sugano, Aki; Ito, Akihiko; Takaoka, Yutaka

2017-12-01

Acupuncture treatment utilizes the stimulation of metal acupuncture needles that are manually inserted into a living body. In the last decades, laser light has been used as an alternative to needles to stimulate acupuncture points. We previously reported suppression of myostatin (Mstn) gene expression in skeletal muscle by means of femtosecond laser (FL) irradiation, after electroacupuncture, in which acupuncture needles are stimulated with a low-frequency microcurrent. The purpose of the study here was to investigate the efficacy of FL irradiation in mouse skeletal muscle with regard to protein synthesis. After irradiation of the hindlimbs, we first analyzed Mstn gene expression and Mstn protein level in the skeletal muscle. We then evaluated phosphorylation of the mammalian target of rapamycin (mTOR) and its downstream target 70-kDa ribosomal protein S6 kinase (p70S6K). The results showed that FL irradiation significantly reduced the amount of Mstn protein and enhanced the phosphorylation of p70S6K in of the mTOR/S6K signaling pathway. We suggest that FL irradiation activated the protein synthetic pathway in the skeletal muscle. In conclusion, we determined that FL irradiation can serve as an alternative for acupuncture needles and has the potential of being a new non-invasive acupuncture treatment of skeletal muscle.

Measurement of droplet size distribution in core region of high-speed spray by micro-probe L2F

NASA Astrophysics Data System (ADS)

Sakaguchi, Daisaku; Le Amida, Oluwo; Ueki, Hironobu; Ishida, Masahiro

2008-03-01

In order to investigate the distribution of droplet sizes in the core region of diesel fuel spray, instantaneous measurement of droplet sizes was conducted by an advanced laser 2-focus velocimeter (L2F). The micro-scale probe of the L2F is made up of two foci and the distance between them is 36 µm. The tested nozzle had a 0.2 mm diameter single-hole. The measurements of injection pressure, needle lift, and crank angle were synchronized with the measurement by the L2F at the position 10 mm downstream from the nozzle exit. It is clearly shown that the droplet near the spray axis is larger than that in the off-axis region under the needle full lift condition and that the spatial distribution of droplet sizes varies temporally. It is found that the probability density distribution of droplet sizes in the spray core region can be fitted to the Nukiyama-Tanasawa distribution in most injection periods.

Chemical reactions and morphological stability at the Cu/Al2O3 interface.

PubMed

Scheu, C; Klein, S; Tomsia, A P; Rühle, M

2002-10-01

The microstructures of diffusion-bonded Cu/(0001)Al2O3 bicrystals annealed at 1000 degrees C at oxygen partial pressures of 0.02 or 32 Pa have been studied with various microscopy techniques ranging from optical microscopy to high-resolution transmission electron microscopy. The studies revealed that for both oxygen partial pressures a 20-35 nm thick interfacial CuAlO2 layer formed, which crystallises in the rhombohedral structure. However, the CuAlO2 layer is not continuous, but interrupted by many pores. In the samples annealed in the higher oxygen partial pressure an additional reaction phase with a needle-like structure was observed. The needles are several millimetres long, approximately 10 microm wide and approximately 1 microm thick. They consist of CuAlO2 with alternating rhombohedral and hexagonal structures. Solid-state contact angle measurements were performed to derive values for the work of adhesion. The results show that the adhesion is twice as good for the annealed specimen compared to the as-bonded sample.

Microstructure and Properties of Lap Joint Between Aluminum Alloy and Galvanized Steel by CMT

NASA Astrophysics Data System (ADS)

Niu, Song; Chen, Su; Dong, Honggang; Zhao, Dongsheng; Zhang, Xiaosheng; Guo, Xin; Wang, Guoqiang

2016-05-01

Lap joining of 1-mm-thick Novelist AC 170 PX aluminum alloy to 1.2-mm-thick ST06 Z galvanized steel sheets for automotive applications was conducted by cold metal transfer advanced welding process with ER4043 and ER4047 filler wires. Under the optimized welding parameters with ER4043 filler wire, the tensile shear strength of joint was 189 MPa, reaching 89% of the aluminum alloy base metal. Microstructure and elemental distribution were characterized by optical metalloscope and electron probe microanalysis. The lap joints with ER4043 filler wire had smaller wetting angle and longer bonded line length with better wettability than with ER4047 filler wire during welding with same parameters. The needle-like Al-Fe-Si intermetallic compounds (IMCs) were spalled into the weld and brought negative effect to the tensile strength of joints. With increasing welding current, the needle-like IMCs grew longer and spread further into the weld, which would deteriorate the tensile shear strength.

Experimental study on the effect of nozzle hole-to-hole angle on the near-field spray of diesel injector using fast X-ray phase-contrast imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Xusheng; Moon, Seoksu; Gao, Jian

Fuel atomization and vaporization process play a critical role in determining the engine combustion and emission. The primary near-nozzle breakup is the vital link between the fuel emerging from the nozzle and the fully atomized spray. In this study, the near-nozzle spray characteristics of diesel injector with different umbrella angle (UA) were investigated using high-speed X-ray phase-contrast imaging and quantitative image processing. A classic ‘dumbbell’ profile of spray width (SW) composed of three stages: opening stage, semisteady stage and closing stage. The SW peak of two-hole injectors was more than twice of that of single-hole injector at the opening andmore » closing stages, corresponding to the hollow-cone spray. This indicated the vortex flow was formed with the increase of the UA. The higher injection pressure had little influence on the SW while led to earlier breakup closer to the nozzle. Significant fuel effect on the SW at higher needle lift was found. However, this effect could be neglect at lower needle lift due to the leading role of internal flow and cavitation on the near-field spray characteristics. In addition, the morphology-based breakup process was observed, which highlighted the important effect of internal flow on the spray development. The possibility of using hollow-cone spray in diesel injector was also discussed.« less

Needle-like instruments for steering through solid organs: A review of the scientific and patent literature.

PubMed

Scali, Marta; Pusch, Tim P; Breedveld, Paul; Dodou, Dimitra

2017-03-01

High accuracy and precision in reaching target locations inside the human body is necessary for the success of percutaneous procedures, such as tissue sample removal (biopsy), brachytherapy, and localized drug delivery. Flexible steerable needles may allow the surgeon to reach targets deep inside solid organs while avoiding sensitive structures (e.g. blood vessels). This article provides a systematic classification of possible mechanical solutions for three-dimensional steering through solid organs. A scientific and patent literature search of steerable instrument designs was conducted using Scopus and Web of Science Derwent Innovations Index patent database, respectively. First, we distinguished between mechanisms in which deflection is induced by the pre-defined shape of the instrument versus mechanisms in which an actuator changes the deflection angle of the instrument on demand. Second, we distinguished between mechanisms deflecting in one versus two planes. The combination of deflection method and number of deflection planes led to eight logically derived mechanical solutions for three-dimensional steering, of which one was dismissed because it was considered meaningless. Next, we classified the instrument designs retrieved from the scientific and patent literature into the identified solutions. We found papers and patents describing instrument designs for six of the seven solutions. We did not find papers or patents describing instruments that steer in one-plane on-demand via an actuator and in a perpendicular plane with a pre-defined deflection angle via a bevel tip or a pre-curved configuration.

Correlating contact line capillarity and dynamic contact angle hysteresis in surfactant-nanoparticle based complex fluids

NASA Astrophysics Data System (ADS)

Harikrishnan, A. R.; Dhar, Purbarun; Agnihotri, Prabhat K.; Gedupudi, Sateesh; Das, Sarit K.

2018-04-01

Dynamic wettability and contact angle hysteresis can be correlated to shed insight onto any solid-liquid interaction. Complex fluids are capable of altering the expected hysteresis and dynamic wetting behavior due to interfacial interactions. We report the effect of capillary number on the dynamic advancing and receding contact angles of surfactant-based nanocolloidal solutions on hydrophilic, near hydrophobic, and superhydrophobic surfaces by performing forced wetting and de-wetting experiments by employing the embedded needle method. A segregated study is performed to infer the contributing effects of the constituents and effects of particle morphology. The static contact angle hysteresis is found to be a function of particle and surfactant concentrations and greatly depends on the nature of the morphology of the particles. An order of estimate of line energy and a dynamic flow parameter called spreading factor and the transient variations of these parameters are explored which sheds light on the dynamics of contact line movement and response to perturbation of three-phase contact. The Cox-Voinov-Tanner law was found to hold for hydrophilic and a weak dependency on superhydrophobic surfaces with capillary number, and even for the complex fluids, with a varying degree of dependency for different fluids.

Usability evaluation of intradermal adapters (IDA).

PubMed

Tsals, Izrail

2017-03-27

Intradermal adapter device technology minimizes the complexity of the Mantoux technique, thereby providing predictable, reproducible intradermal (ID) injections and removing the concerns regarding the ease and reliability of Mantoux technique when using conventional needle and syringe. The technology employs a simple device with geometry designed to gently deform the skin surface and the subcutaneous tissue, providing the ideal angle and depth of needle insertion for consistently successful intradermal injections. The results of this development were presented at the First, Second and Third Skin Vaccination Summits in 2011, 2013 and 2015 respectively [1,2,3]. The current publication addresses the performance of intradermal adapters (IDA) evaluated in three preclinical studies. The evaluations were based on the assessment of bleb formation in a skin model, an accepted indicator of ID injection success. All evaluated devices share the same proprietary dermal interface technology. Devices instituting this design are easy to use, require minimal training, and employ conventionally molded parts and cannula. These studies evaluated IDAs of initial design integral with luer lock needles, IDAs for use with conventional syringes, and intradermal adapters for use with auto disable syringes (ADID adapters). The evaluated ID adapters were intended to consistently place the lancet of the needle at a depth of 0.75mm from the skin's surface. This placement depth addresses the variation in the skin thickness at immunization sites for the majority of patients independent of many other variables. Most participants preferred the intradermal adapter method over the traditional Mantoux and identified a need for the adapter at their workplace. Evaluation of IDAs by registered nurses indicated these devices increase success of bleb formation. The use of IDA increased the success of forming blebs by about 30%. Nurses felt the injections were much easier to perform, in particular by novices. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous Multi-angle Observations of Strong Langmuir Turbulence at HAARP

NASA Astrophysics Data System (ADS)

Watanabe, Naomi; Golkowski, Mark; Sheerin, James P.; Watkins, Brenton J.

2015-10-01

We report results from a recent series of experiments employing the HF transmitter of the High Frequency Active Auroral Research Program (HAARP) to generate and study strong Langmuir turbulence (SLT) in the interaction region of overdense ionospheric plasma. The Modular UHF Ionospheric Radar (MUIR) located at the HAARP facility is used as the primary diagnostic. Short pulse, low duty cycle experiments are used to avoid generation of artificial field-aligned irregularities and isolate ponderomotive plasma turbulence effects. The HF pump frequency is close to the 3rd gyro-harmonic frequency and the HF pointing angle and MUIR look angle are between the HF Spitze angle and Magnetic Zenith angle. Plasma line spectra measured simultaneously in different spots of the interaction region display differences dependent on the aspect angle of the HF pump beam in the boresight direction and the pointing angle of the MUIR diagnostic radar. Outshifted Plasma Lines, cascade, collapse, coexistence, spectra are observed in agreement with existing theory and simulation results of Strong Langmuir Turbulence in ionospheric interaction experiments. It is found that SLT at HAARP is most readily observed at a HF pointing angle of 11° and UHF observation angle of 15°, which is consistent with the magnetic zenith effect as documented in previous works and optimal orientation of the refracted HF electric field vector.

Buffeting of NACA 0012 airfoil at high angle of attack

NASA Astrophysics Data System (ADS)

Zhou, Tong; Dowell, Earl

2014-11-01

Buffeting is a fluid instability caused by flow separation or shock wave oscillations in the flow around a bluff body. Typically there is a dominant frequency of these flow oscillations called Strouhal or buffeting frequency. In prior work several researchers at Duke University have noted the analogy between the classic Von Karman Vortex Street behind a bluff body and the flow oscillations that occur for flow around a NACA 0012 airfoil at sufficiently large angle of attack. Lock-in is found for certain combinations of airfoil oscillation (pitching motion) frequencies and amplitudes when the frequency of the airfoil motion is sufficiently close to the buffeting frequency. The goal of this paper is to explore the flow around a static and an oscillating airfoil at high angle of attack by developing a method for computing buffet response. Simulation results are compared with experimental data. Conditions for the onset of buffeting and lock-in of a NACA 0012 airfoil at high angle of attack are determined. Effects of several parameters on lift coefficient and flow response frequency are studied including Reynolds number, angle of attack and blockage ratio of the airfoil size to the wind tunnel dimensions. Also more detailed flow field characteristics are determined. For a static airfoil, a universal Strouhal number scaling has been found for angles of attack from 30° to 90°, where the flow around airfoil is fully separated. For an oscillating airfoil, conditions for lock-in are discussed. Differences between the lock-in case and the unlocked case are also studied. The second affiliation: Duke University.

Qualitative numerical studies of the modification of the pitch angle distribution of test particles by alfvènic wave activity

NASA Astrophysics Data System (ADS)

Keilbach, D.; Drews, C.; Berger, L.; Marsch, E.; Wimmer-Schweingruber, R. F.

2017-12-01

Using a test particle approach we have investigated, how an oxygen pickup ion torus velocity distribution is modified by continuous and intermittent alfvènic waves on timescales, where the gyro trajectory of each particle can be traced.We have therefore exposed the test particles to mono frequent waves, which expanded through the whole simulation in time and space. The general behavior of the pitch angle distribution is found to be stationary and a nonlinear function of the wave frequency, amplitude and the initial angle between wave elongation and field-perpendicular particle velocity vector. The figure shows the time-averaged pitch angle distributions as a function of the Doppler shifted wave frequency (where the Doppler shift was calculated with respect to the particles initial velocity) for three different wave amplitudes (labeled in each panel). The background field is chosen to be 5 nT and the 500 test particles were initially distributed on a torus with 120° pitch angle at a solar wind velocity of 450 km/s. Each y-slice of the histogram (which has been normalized to it's respective maximum) represents an individual run of the simulation.The frequency-dependent behavior of the test particles is found to be classifiable into the regimes of very low/high frequencies and frequencies close to first order resonance. We have found, that only in the latter regime the particles interact strongly with the wave, where in the time averaged histograms a branch structure is found, which was identified as a trace of particles co-moving with the wave phase. The magnitude of pitch angle change of these particles is as well as the frequency margin, where the branch structure is found, an increasing function with the wave amplitude.We have also investigated the interaction with mono frequent intermittent waves. Exposed to such waves a torus distribution is scattered in pitch angle space, whereas the pitch angle distribution is broadened systematically over time similar to pitch angle diffusion.The framework of our simulations is a first step toward understanding wave particle interactions at the most basic level and is readily expandable to e.g. the inclusion of multiple wave frequencies, intermittent wave activity, gradients in the background magnetic field or collisions with solar wind particles.

Simultaneous piston position and tilt angle sensing for large vertical displacement micromirrors by frequency detection inductive sensing

NASA Astrophysics Data System (ADS)

Tseng, V. F.-G.; Xie, H.

2015-11-01

This paper presents a frequency detection based inductive eddy current sensing mechanism to simultaneously sense the piston position and tilt angle of the mirror plate of large vertical displacement micromirrors that exhibit piston scan ranges above 100 μm. This is accomplished by sensing the inductance change, and thus resonant frequency shift, of two microfabricated sensing coils packaged underneath the mirror plate. For demonstration purpose, the coils were paired with discrete circuit components to oscillate at 11.9 MHz and 12.5 MHz, respectively. The piston position and tilt angle of the mirror plate could be simultaneously monitored over a 500 μm piston scan range, achieving a maximum piston sensitivity of 4.15 kHz/μm with a piston sensing resolution of 96 nm and a maximum tilt angle sensitivity of 60.5 kHz/° with a tilt angle sensing resolution of 0.0013°. Analytical modeling of the coil inductance change via image theory was also conducted, showing that the sensor sensitivity and resolution could be improved by increasing the coil oscillation frequency and decreasing the coil size.

Robotics, telesurgery and telementoring--their position in modern urological laparoscopy.

PubMed

Rassweiler, Jens; Frede, Thomas

2002-01-01

Laparoscopic surgery in general is handicapped by the reduction of the range of motion from six to four degrees of freedom. This has a major impact on technically difficult procedures such as laparoscopic radical prostatectomy. Solutions for this problems include the understanding of the geometry of laparoscopy with sophisticated training programs, but lie also in newly developed surgical robots, computer simulators and telementoring. This article evaluates the value of these alternatives based on own experiences and an analysis of the current literature. Own experiences with robot-assisted surgery include 406 laparoscopic radical prostatectomies using a voice-controlled camera-arm (AESOP) as well as 6 telesurgical interventions with the Da Vinci-system. Additionally, substantial experimental studies have been performed focussing on the geometry of laparoscopy and new training concepts such as perfused pelvitrainers and computer simulation. Moreover, the current literature of the last 10 years on telesurgery and telementoring has been reviewed. The geometry of laparoscopy includes the angles between the instruments which have to be in a range of 25 degrees to 45 degrees; the angles between the instrument and the working plane that should not exceed 55 degrees; and the angle between the shaft of the needle holder and the needle which has to be adapted according to the anatomical situation in range of 90 to 110 degrees. 3-D-systems did not yet proved to be effective due to handling problems such as shutter glasses, video-helmets or reduced brightness. At the moment, there are only two robotic surgical systems (ZEUS, Da Vinci) in clinical use for telesurgery, of which only the Da Vinci provides stereovision and all six degrees of freedom (DOF). In the meantime, more than 200 laparoscopic radical prostatectomies have been performed with this system. Until now, however, there was no evidence of any advantages over the conventional laparoscopic approach. The ZEUS in combination with the telecommunication system SOKRATES is the only device enabling to realize telemanipulation and telementoring over long distances (i.e. transatlantic). Robotic surgery represents a turning point of surgical research. However, broad use of robotic systems is limited mainly because of the high investment and running costs. Whereas there will be a clear role of audio-visual telementoring in future training concepts, the need of telemanipulation/telesurgery has not yet been clarified. New technological concepts promote the development of hand-held mechanical manipulators (i.e. 6-DOF-needle-holder) used in combination with mono-tasking computerized robots (i.e. AESOP) resulting in a significant cost reduction.

Dynamic Cerebral Autoregulation is Preserved During Acute Head-down Tilt

DTIC Science & Technology

2003-06-27

relationship of mean arterial pressure to mean cerebral blood flow velocity transfer function gain at the high and low frequencies, respectively; TCD-PHASE...HF and TCD-PHASE-LF, phase angle between mean arterial pressure and mean cerebral blood flow veloc- ity at high and low frequencies, respectively...arterial pressure and mean ce- rebral blood flow oscillations decrease from low- to high -frequency ranges. Average phase angles were 68° at low frequencies

Type and frequency of side effects during PC6 acupuncture: observations from therapists and patients participating in clinical efficacy trials of acupuncture.

PubMed

Enblom, Anna; Johnsson, Anna

2017-12-01

Many therapists practise PC6 acupuncture for emesis (nausea and vomiting) during pregnancy, different cancer therapies, palliative care, after surgery, or to induce relaxing effects in general. Knowledge of side effects is central to shared decision-making. To describe the type and frequency of side effects and the level of needle-induced pain during PC6 acupuncture. We included 1298 PC6 acupuncture treatments, delivered to 221 participants (77% women, mean age 52.5, range 18-91 years). The subjects had received genuine PC6 acupuncture, in one of two previous randomised controlled trials, aimed at inducing antiemetic (n=100, with 100 providing data on side effects and 94 on needle-induced pain, respectively) or relaxing (n=121, with 120 providing data) effects. Side effects during and after the acupuncture treatments were registered in structured treatment protocols and study diaries. No serious complications occurred. Side effects during the acupuncture sessions included minor bleeding in 5.0%, tiredness in 4.9%, numbness in 4.5% and dizziness in 1.4% of the 1298 treatments. After treatment, the mean proportions of participants reporting side effects each week were: tiredness 25.8%; feeling cold 17.8%; dizziness 9.7%; sweating 9.3%; haematoma 8.8%; and soreness at the needling sites 4.3%. Participants perceived the needling to be not painful (47.4% of participants), or mildly (39.1%), moderately (11.6%) or very painful (1.4%). Few side effects occurred and those that did were mild. Nearly 90% found PC6 acupuncture to be not painful or only mildly painful. Healthcare professionals may consider the observed levels of side effects when informing patients about side effects of PC6 acupuncture. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Physical evaluation of a needle photostimulable phosphor based CR mammography system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, Nicholas W.; Lemmens, Kim; Bosmans, Hilde

2012-02-15

Purpose: Needle phosphor based computed radiography (CR) systems promise improved image quality compared to powder phosphor based CR units for x-ray screening mammography. This paper compares the imaging performance of needle CR cassettes, powder based CR cassettes and a well established amorphous selenium (a-Se) based flat panel based mammography system, using consistent beam qualities. Methods: Detector performance was assessed using modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE). Mammography system performance was assessed against levels from the European Guidelines, including threshold gold thickness (c-d), relative signal difference to noise (SdNR) and mean glandular dose,more » for automatic exposure control settings suggested by the manufacturers. The needle based Agfa HM5.0 CR detector was compared against the single sided readout Agfa MM3.0R and dual sided readout Fuji Profect CS powder CR plates using a 28 kV Mo/Rh spectrum, while a 28 kV W/Rh spectrum was used to compare the Agfa HM5.0 against the Siemens MAMMOMAT Inspiration a-Se based system. Results: MTF at 5 mm{sup -1} was 0.16 and 0.24 for the needle CR detector in the fast and slow scan directions, respectively, indicating a slight improvement ({approx}20%) over the two powder CR systems but remained 50% lower than the result at 5 mm{sup -1} for the a-Se detector ({approx}0.55). Structured screen noise was lower for the needle phosphor compared to the powder plates. CR system gain, estimated from the measured absorption fraction and NNPS results, was 6.3 for the (single sided) needle phosphor and 5.1 and 7.2 for the single sided and dual sided powder phosphor systems. Peak DQE at {approx}100 {mu}Gy was 0.47 for the needle system compared to peak DQE figures of 0.33 and 0.46 for the single sided readout powder plates and dual sided readout plates. The high frequency DQE (at 5 mm{sup -1}) was 0.19 for the needle CR plates, a factor of approximately 3 greater than for the powder CR plates. At 28 kV W/Rh, 2 mm Al, peak DQE for the needle CR system was 0.45 against a value of 0.50 for the a-Se detector. The needle CR detector reached the Acceptable limit for 0.1 mm details in the European Guidelines at a mean glandular dose (MGD) of approximately 1.31 mGy imaged at 28 kV Mo/Rh, compared to figures of 2.19 and 1.43 mGy for the single sided and dual sided readout powder CR systems. The a-Se detector could reach the limit at 0.65 mGy using a 28 kV W/Rh spectrum, while the needle CR system required 1.09 mGy for the same spectrum. Conclusions: Imaging performance for the needle CR phosphor technology, characterized using MTF and DQE and threshold gold thickness demonstrated a clear improvement compared to both single and dual sided reading powder phosphor based CR systems.« less

Needle-free jet injection for administration of influenza vaccine: a randomised non-inferiority trial.

PubMed

McAllister, Linda; Anderson, Jonathan; Werth, Kristen; Cho, Iksung; Copeland, Karen; Le Cam Bouveret, Nancy; Plant, David; Mendelman, Paul M; Cobb, David K

2014-08-23

Administration of vaccines by needle-free technology such as jet injection might offer an alternative to needles and syringes that avoids the issue of needle phobia and the risk of needle-stick injury. We aimed to assess the immunogenicity and safety of trivalent influenza vaccine given by needle-free jet injector compared with needle and syringe. For this randomised, comparator-controlled trial, we randomly assigned (1:1) healthy adults (aged 18-64 years) who attended one of four employee health clinics in the University of Colorado health system, with stratification by site, to receive one dose of the trivalent inactivated influenza vaccine Afluria given either intramuscularly with a needle-free jet injector (Stratis; PharmaJet, Golden, CO, USA) or with needle and syringe. Randomisation was done with a computer-generated randomisation schedule with a block size of 100. Because of the nature of the study, masking of participants was not possible. Immunogenicity was assessed by measurement of the hemagglutination inhibition antibody titres in serum for the three viral strains included in the vaccine. We included six coprimary endpoints: three strain-specific geometric mean titre ratios and the absolute differences in three strain-specific seroconversion rates. The immune response of the jet injector group was regarded as non-inferior to that of the needle and syringe group if both the upper bound of each of the three 95% CIs for the strain-specific geometric mean titre ratios was 1.5 or less, and the upper bound of the three 95% CIs for the strain-specific seroconversion rate differences was less than 10 percentage points. We used t test for group comparison. This study is registered with ClinicalTrials.gov, number NCT01688921. During the 2012-13 influenza season of the northern hemisphere, we allocated 1250 participants to receive vaccination by needle-free jet injector (n=627) or needle and syringe (n=623). In the intention-to-treat immunogenicity population, all participants with two serum samples were included (575 in the jet injector group and 574 in the needle and syringe group). The immune response to Afluria when given by needle-free jet injector met the criteria for non-inferiority for all six coprimary endpoints. The jet injector group met the geometric mean titre criterion for non-inferiority for the A/H1N1, A/H3N2, and B strains (upper bound of the 95% CI for the geometric mean titre ratios were 1·10 for A/H1N1, 1·17 for A/H3N2, and 1·04 for B strains). The jet injector group met the seroconversion rate criterion for non-inferiority for the A/H1N1, A/H3N2, and B strains (upper bound of the 95% CI of the seroconversion rate differences were 6·0% for A/H1N1, 7·0% for A/H3N2, and 5·7% for B strains). We recorded serious adverse events in three participants, none of which were study related. The immune response to influenza vaccine given with the jet injector device was non-inferior to the immune response to influenza vaccine given with needle and syringe. The device had a clinically acceptable safety profile, but was associated with a higher frequency of local injection site reactions than was the use of needle and syringe. The Stratis needle-free jet injector device could be used as an alternative method of administration of Afluria trivalent influenza vaccine. Biomedical Advanced Research and Development Authority (BARDA), PATH, bioCSL, and PharmaJet. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Assessment of amylase and lipase levels following puncture biopsy and fine needle aspiration guided by endoscopic ultrasound in pancreatic lesions].

PubMed

Membrillo-Romero, Alejandro; Gonzalez-Lanzagorta, Rubén; Rascón-Martínez, Dulce María

Puncture biopsy and fine needle aspiration guided by endoscopic ultrasound has been used as an effective technique and is quickly becoming the procedure of choice for diagnosis and staging in patients suspected of having pancreatic cancer. This procedure has replaced retrograde cholangiopancreatography and brush cytology due to its higher sensitivity for diagnosis, and lower risk of complications. To assess the levels of pancreatic enzymes amylase and lipase, after the puncture biopsy and fine needle aspiration guided by endoscopic ultrasound in pancreatic lesions and the frequency of post-puncture acute pancreatitis. A longitudinal and descriptive study of consecutive cases was performed on outpatients submitted to puncture biopsy and fine needle aspiration guided by endoscopic ultrasound in pancreatic lesions. Levels of pancreatic enzymes such as amylase and lipase were measured before and after the pancreatic puncture. Finally we documented post-puncture pancreatitis cases. A total of 100 patients who had been diagnosed with solid and cystic lesions were included in the study. Significant elevation was found at twice the reference value for lipase in 5 cases (5%) and for amylase in 2 cases (2%), none had clinical symptoms of acute pancreatitis. Eight (8%) of patients presented with mild nonspecific pain with no enzyme elevation compatible with pancreatitis. Pancreatic biopsy needle aspiration guided by endoscopic ultrasound was associated with a low rate of elevated pancreatic enzymes and there were no cases of post-puncture pancreatitis. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

Deactivation of Escherichia coli by the plasma needle

NASA Astrophysics Data System (ADS)

Sladek, R. E. J.; Stoffels, E.

2005-06-01

In this paper we present a parameter study on deactivation of Escherichia coli (E. coli) by means of a non-thermal plasma (plasma needle). The plasma needle is a small-sized (1 mm) atmospheric glow sustained by radio-frequency excitation. This plasma will be used to disinfect heat-sensitive objects; one of the intended applications is in vivo deactivation of dental bacteria: destruction of plaque and treatment of caries. We use E. coli films plated on agar dishes as a model system to optimize the conditions for bacterial destruction. Plasma power, treatment time and needle-to-sample distance are varied. Plasma treatment of E. coli films results in formation of a bacteria-free void with a size up to 12 mm. 104-105 colony forming units are already destroyed after 10 s of treatment. Prolongation of treatment time and usage of high powers do not significantly improve the destruction efficiency: short exposure at low plasma power is sufficient. Furthermore, we study the effects of temperature increase on the survival of E. coli and compare it with thermal effects of the plasma. The population of E. coli heated in a warm water bath starts to decrease at temperatures above 40°C. Sample temperature during plasma treatment has been monitored. The temperature can reach up to 60°C at high plasma powers and short needle-to-sample distances. However, thermal effects cannot account for bacterial destruction at low power conditions. For safe and efficient in vivo disinfection, the sample temperature should be kept low. Thus, plasma power and treatment time should not exceed 150 mW and 60 s, respectively.

The Timing of Acupuncture Stimulation Does Not Influence Anesthetic Requirement

PubMed Central

Chernyak, Grigory; Sengupta, Papiya; Lenhardt, Rainer; Liem, Edwin; Doufas, Anthony G.; Sessler, Daniel I.; Akça, Ozan

2005-01-01

Studies suggest that acupuncture is more effective when induced before induction of general anesthesia than afterwards. We tested the hypothesis that electro-acupuncture initiated 30 minutes before induction reduces anesthetic requirement more than acupuncture initiated after induction. Seven volunteers were each anesthetized with desflurane on 3 study days. Needles were inserted percutaneously at 4 acupuncture points thought to produce analgesia in the upper abdominal area and provide generalized sedative and analgesic effects: Zusanli (St36), Sanyinjiao (Sp6), Liangqiu (St34), and Hegu (LI4). Needles were stimulated at 2-Hz and 10-Hz, with frequencies alternating at two-second intervals. On Preinduction day, electro-acupuncture was started 30 minutes before induction of anesthesia and maintained throughout the study. On At-induction day, needles were positioned before induction of anesthesia, but electro-acupuncture stimulation was not initiated until after induction. On Control day, electrodes were positioned near the acupoints, but needles were not inserted. Noxious electrical stimulation was administered via 25-G needles on the upper abdomen (70 mA, 100 Hz, 10 seconds). Desflurane concentration was increased 0.5% when movement occurred and decreased 0.5% when it did not. These up-and-down sequences continued until volunteers crossed from movement to no-movement 4 times. The P50 of logistic regression identified desflurane requirement. Desflurane requirement was similar on the Control (5.2±0.6%, mean±SD), Preinduction (5.0±0.8%), and At-induction (4.7±0.3%, P=0.125) days. This type of acupuncture is thus unlikely to facilitate general anesthesia or decrease the need for anesthetic drugs. PMID:15673863

Proof of the Wave Nature of Plants

NASA Astrophysics Data System (ADS)

Wagner, Orvin

2008-03-01

I assume plants operate with a set of frequencies. These frequencies and the means of these frequencies are equal in all directions. We can then write (vh/λ)avh=(vv/λ)avv where the subscripts h and v represent horizontal and vertical respectively and av is average,. or vv/vh=(1/λh)av/(1/λv)av. I use an internodal spacing as λ/2 or the the distance between adjacent branches, leaves, etc. The ratios, vv/vh, are ratios of small integers for sufficient samplings. For example, for Ponderosa pine the ratio is 3/1 or for delicious apple 4/3. Note that these ratios represent the shape of the tree or other plant and their interactions with gravity. These ratios are derivable by other means such as use the ratio of # of horizontal needles per unit length from a horizontal sample to the # of needles per unit length from a vertical sample from p-pine. Or measure the vertical and horizontal velocities. My literature provides many other proofs of the wave nature of plants. I suggest that the waves in and related waves outside of plants (outside 4.9 m/s) are a dark matter related since they travel at such low velocities. See my present web site at home.budget.net/˜oedphd.

[Amplitude Changes of Low Frequency Fluctuation in Brain Spontaneous Nervous Activities Induced by Needling at Hand Taiyin Lung Channel].

PubMed

Zhou, You-long; Su, Cheng-guo; Liu, Shou-fang; Jin, Xiang-yu; Duan, Yan-li; Chen, Xiao-yan; Zhao, Shu-hua; Wang, Quan-liang; Dang, Chang-lin

2016-05-01

To observe amplitude changes of low frequency fluctuation in brain spontaneous nervous activities induced by needling at Hand Taiyin Lung Channel, and to preliminarily explore the possible brain function network of Hand Taiyin Lung Channel. By using functional magnetic resonance imaging (fMRI), 16 healthy volunteers underwent resting-state scanning (R1) and scanning with retained acupuncture at Hand Taiyin Lung Channel (acupuncture, AP). Data of fMRI collected were statistically calculated using amplitude of low frequency fluctuations (ALFF). Under R1 significantly enhanced ALFF occurred in right precuneus, left inferior parietal lobule, bilateral superior temporal gyrus, bilateral middle frontal gyrus, left superior frontal gyrus, left inferior frontal gyrus, left medial frontal gyrus. Under AP significantly enhanced ALFF occurred in right precuneus, bilateral superior frontal gyrus, cerebellum, bilateral middle frontal gyrus, right medial frontal gyrus, and so on. Compared with R1, needing at Hand Taiyin Lung Channel could significantly enhance ALFF in right gyrus subcallosum and right inferior frontal gyrus. Significant decreased ALFF appeared in right postcentral gyrus, left precuneus, left superior temporal gyrus, left middle temporal gyrus, and so on. Needing at Hand Taiyin Lung Channel could significantly change fixed activities of cerebral cortex, especially in right subcallosal gyrus, right inferior frontal gyrus, and so on.

Wide Angle, Single Screen, Gridded Square-Loop Frequency Selective Surface for Diplexing Two Closely Separated Frequency Bands

NASA Technical Reports Server (NTRS)

Wu, Te-Kao (Inventor)

1996-01-01

The design and performance of a wide angle, single screen, frequency selective surface (FSS) with gridded square-loop path elements are described for diplexing closely separated signal bands, for example, X- and Ku-band signals in an Orbiting Very Long Baseline Interferometer (OVLBI) earth station reflector antenna system, as well as other applications such as military and commercial communications via satellites. Excellent agreement is obtained between the predicted and measured results of this FSS design using the gridded square-loop patch elements sandwiched between 0.0889 cm thick tetrafluoroethylene fluorocarbon polymer (PTFE) slabs. Resonant frequency drift is reduced by 1 GHz with an incidence angle from 0 deg normal to 40 deg from normal.

Electron spin resonance from NV centers in diamonds levitating in an ion trap

NASA Astrophysics Data System (ADS)

Delord, T.; Nicolas, L.; Schwab, L.; Hétet, G.

2017-03-01

We report observations of the electron spin resonance (ESR) of nitrogen vacancy centers in diamonds that are levitating in an ion trap. Using a needle Paul trap operating under ambient conditions, we demonstrate efficient microwave driving of the electronic spin and show that the spin properties of deposited diamond particles measured by the ESR are retained in the Paul trap. We also exploit the ESR signal to show angle stability of single trapped mono-crystals, a necessary step towards spin-controlled levitating macroscopic objects.

Droplets act as compass needles for the tension in a membrane

NASA Astrophysics Data System (ADS)

Schulman, Rafael; Ledesma-Alonso, Rene; Salez, Thomas; Raphael, Elie; Dalnoki-Veress, Kari

We present experiments which study droplets atop thin elastomeric films with anisotropic tension. Surprisingly, we find that the droplets are not spherical caps and become elongated along the axis of highest tension. As such, liquid droplets create a map for the principal stress directions in a film. In our experiments, we completely determine the contact line geometry using a combination of contact angle measurements and optical profilometry. In addition, we measure an out-of-plane deformation of the film surrounding the droplet. Simple theoretical arguments successfully capture the experimental findings.

Prevalence and correlates of HIV infection among men who inject drugs in a remote area of Vietnam.

PubMed

Nghiem, Van T; Bui, Thanh C; Nadol, Patrick P; Phan, Son H; Kieu, Binh T; Kling, Ryan; Hammett, Theodore M

2018-02-14

Lack of information on the HIV epidemic among men who inject drugs (MWID) in northwestern Vietnam, a remote area, may hamper national efforts to control the disease. We examined HIV prevalence, needle-syringe sharing behaviors, and associated factors among MWID in three areas of northwestern Vietnam. We used descriptive analysis to report the characteristics, frequency of risk behaviors, and of access to healthcare services among the MWID. Univariable logistic regression was used to assess the associations between the HIV infection, needle-syringe sharing behaviors, and their independent variables. We further explored these associations in multivariable analyses where we included independent variables based on a priori knowledge and their associations with the dependent variables determined in univariable analyses (p <  0.25). The HIV prevalence was 37.9, 16.9, and 18.5% for Tuan Giao, Bat Xat, and Lao Cai City, respectively, and 25.4% overall. MWID of Thai minority ethnicity were more likely to be HIV-positive (adjusted odds ratio (AOR) 3.55; 95% confidence interval (CI) 1.84-6.87). The rate of needle-syringe sharing in the previous 6 months was approximately 9% among the MWID in Tuan Giao and Lao Cai City, and 27.8% in Bat Xat. Two thirds of the participants never underwent HIV testing before this study. Ever having been tested for HIV before this study was not associated with any needle-syringe sharing behaviors. Among the HIV-positive MWID, those who received free clean needles and syringes were less likely to give used needles and syringes to peers (AOR 0.21; 95% CI 0.06-0.79). Going to a "hotspot" in the previous week was associated with increased odds of needle-syringe sharing in multiple subgroups. Our findings on HIV prevalence and testing participation among a subset of MWID in the northwestern Vietnam were corroborated with trend analysis results from the most recent HIV/STI Integrated Biological and Behavioral Surveillance report (data last collected in 2013.) We provided important insights into these MWID's risky injection behaviors. We suggest heightened emphasis on HIV testing and needle and syringe provision for this population. Also, policymakers and program implementers should target hotspots as a main venue to tackle HIV epidemics.

[Research of bleeding volume and method in blood-letting acupuncture therapy based on data mining].

PubMed

Liu, Xin; Jia, Chun-Sheng; Wang, Jian-Ling; Du, Yu-Zhu; Zhang, Xiao-Xu; Shi, Jing; Li, Xiao-Feng; Sun, Yan-Hui; Zhang, Shen; Zhang, Xuan-Ping; Gang, Wei-Juan

2014-03-01

Through computer-based technology and data mining method, with treatment in cases of bloodletting acupuncture therapy in collected literature as sample data, the association rule in data mining was applied. According to self-built database platform, the data was input, arranged and summarized, and eventually required data was acquired to perform the data mining of bleeding volume and method in blood-letting acupuncture therapy, which summarized its application rules and clinical values to provide better guide for clinical practice. There were 9 kinds of blood-letting tools in the literature, in which the frequency of three-edge needle was the highest, accounting for 84.4% (1239/1468). The bleeding volume was classified into six levels, in which less volume (less than 0.1 mL) had the highest frequency (401 times). According to the results of the data mining, blood-letting acupuncture therapy was widely applied in clinical practice of acupuncture, in which use of three-edge needle and less volume (less than 0.1 mL) of blood were the most common, however, there was no central tendency in general.

Analysis of Wind Tunnel Lateral Oscillatory Data of the F-16XL Aircraft

NASA Technical Reports Server (NTRS)

Klein, Vladislav; Murphy, Patrick C.; Szyba, Nathan M.

2004-01-01

Static and dynamic wind tunnel tests were performed on an 18% scale model of the F-16XL aircraft. These tests were performed over a wide range of angles of attack and sideslip with oscillation amplitudes from 5 deg. to 30 deg. and reduced frequencies from 0.073 to 0.269. Harmonic analysis was used to estimate Fourier coefficients and in-phase and out-of-phase components. For frequency dependent data from rolling oscillations, a two-step regression method was used to obtain unsteady models (indicial functions), and derivatives due to sideslip angle, roll rate and yaw rate from in-phase and out-of-phase components. Frequency dependence was found for angles of attack between 20 deg. and 50 deg. Reduced values of coefficient of determination and increased values of fit error were found for angles of attack between 35 deg. and 45 deg. An attempt to estimate model parameters from yaw oscillations failed, probably due to the low number of test cases at different frequencies.

Direct CFD Predictions of Low Frequency Sounds Generated by a Helicopter Main Rotor

DTIC Science & Technology

2010-05-01

modeling and grid constraints. NOTATION α Shaft tilt (corrected) or tip-path-plane angle BPF Blade passing frequency CT/σ Thrust coefficient to rotor...cyclic pitch angle, deg. LFSPL Low frequency sound metric (1st-6th BPF ), dB MFSPL Mid frequency sound metric (> 6th BPF ), dB OASPL Overall sound metric...Tunnel of the National Full- Scale Aerodynamic Complex (NFAC) at NASA Ames Research Center in 2008 (Fig. 2a), as a guide for prediction validation. The

Nature, diffraction-free propagation via space-time correlations, and nonlinear generation of time-diffracting light beams

NASA Astrophysics Data System (ADS)

Porras, Miguel A.

2018-06-01

We investigate the properties of the recently introduced time-diffracting (TD) beams in free space. They are shown to be paraxial and quasimonochromatic realizations of spatiotemporal localized waves traveling undistorted at arbitrary speeds. The paraxial and quasimonochromatic regime is shown to be necessary to observe what can properly be named diffraction in time. In this regime, the spatiotemporal frequency correlations for diffraction-free propagation are approximated by parabolic correlations. Time-diffracting beams of finite energy traveling at quasiluminal velocities are seen to form substantially longer foci or needles of light than the so-called abruptly focusing and defocusing needle of light or limiting TD beam of infinite speed. Exploring the properties of TD beams under Lorentz transformations and their transformation by paraxial optical systems, we realize that the nonlinear polarization of material media induced by a strongly localized fundamental pump wave generates a TD beam at its second harmonic, whose diffraction-free behavior as a needle of light in free space can be optimized with a standard 4 f -imager system.

Polymerase chain reaction in the detection of tumor cells: new approaches in diagnosis and follow-up of patients with thyroid cancer.

PubMed

Bojunga, Jörg; Kusterer, Klaus; Schumm-Draeger, Petra-Maria; Usadel, Klaus-Henning

2002-12-01

Thyroid cancers are the most common endocrine malignancies and are being diagnosed with increasing frequency. In addition to other measures, diagnosis is based on fine-needle aspiration cytology examination. Recently, new assays using reverse transcription-polymerase chain reaction (PCR) are being tested to improve sensitivity and specificity of primary diagnosis and detection of recurrent thyroid cancer. In the preoperative diagnosis of thyroid cancer, several tissue- and/or tumor-specific mRNA have been described and in several cases, a higher sensitivity and specificity could be achieved using molecular techniques compared to conventional methods. In the postoperative follow-up of patients with thyroid cancer, conflicting data have been published and the use of PCR techniques revealed several problems of the molecular approach, which are based on some technical as well as biologic limitations. Despite these problems, which are discussed in detail in this review, molecular techniques may nevertheless improve the sensitivity and accuracy of fine-needle aspiration of thyroid nodules, fine-needle aspiration of metastases, and detection of recurrent disease in peripheral blood samples.

Phase field kinetics of lithium electrodeposits

NASA Astrophysics Data System (ADS)

Ely, David R.; Jana, Aniruddha; García, R. Edwin

2014-12-01

A phase field description is formulated to describe the growth kinetics of an heterogeneously nucleated distribution of lithium electrodeposits. The underlying variational principle includes the bulk electrochemical contributions to the free energy of transformation of the system, the electrolyte-dendrite interfacial energy, and the substrate work of adhesion energetics. Results demonstrate that the rate of electrodeposition at the tip of an isolated dendrite is higher than the rate corresponding to the average overpotential, while the back contact is electrochemically shielded, thus favoring elongated, needle-like shapes. For large populations of electrochemically interacting deposits, two spatially distinct regions of behavior develop: one directly facing the counter-electrode where the local surficial electrodeposition dominates the local kinetics; and a second region, in the vicinity of the substrate-deposit interface, where the electrochemical shielding induced by the tip enables lateral electrochemical lithium exchange dendrite coalescence for small contact angle deposits, and dendrite dewetting and electrodissolution for large contact angle deposits. The underlying physical mechanisms through which some lithium nuclei detach from the depositing substrate, self-induce electrodissolution, while other continue to grow and coalesce are described for different contact angles.

Frequency tripling of convergent beam employing crystals tiling in large-aperture high-energy laser facilities

NASA Astrophysics Data System (ADS)

Wang, Junhua; Li, Dazhen; Wang, Bo; Yang, Jing; Yang, Houwen; Wang, Xiaoqian; Cheng, Wenyong

2017-11-01

In inertial confinement fusion, ultraviolet laser damage of the fused silica lens is an important limiting factor for load capability of the laser driver. To solve this problem, a new configuration of frequency tripling is proposed in this paper. The frequency tripling crystal is placed on downstream of the focusing lens, thus sum frequency generation of fundamental frequency light and doubling frequency light occurs in the beam convergence path. The focusing lens is only irradiated by fundamental light and doubling frequency lights. Thus, its damage threshold will increase. LiB3O5 (LBO) crystals are employed as frequency tripling crystals for its larger acceptance angle and higher damage threshold than KDP/DKDP crystals'. With the limitation of acceptance angle and crystal growth size are taken into account, the tiling scheme of LBO crystals is proposed and designed optimally to adopt to the total convergence angle of 36.0 mrad. Theoretical results indicate that 3 LBO crystals titling with different cutting angles in θ direction can meet the phase matching condition. Compared with frequency tripling of parallel beam using one LBO crystal, 83.8% (93.1% with 5 LBO crystals tiling) of the frequency tripling conversion efficiency can be obtained employing this new configuration. The results of a principle experiment also support this scheme. By employing this new design, not only the load capacity of a laser driver will be significantly improved, but also the fused silica lens can be changed to K9 glass lens which has the mature technology and low cost.

ELECTRIC PHASE ANGLE OF CELL MEMBRANES

PubMed Central

Cole, Kenneth S.

1932-01-01

From the theory of an electric network containing any combination of resistances and a single variable impedance element having a constant phase angle independent of frequency, it is shown that the graph of the terminal series reactance against the resistance is an arc of a circle with the position of the center depending upon the phase angle of the variable element. If it be assumed that biological systems are equivalent to such a network, the hypotheses are supported at low and intermediate frequencies by data on red blood cells, muscle, nerve, and potato. For some tissues there is a marked divergence from the circle at high frequencies, which is not interpreted. PMID:19872673

Study of post dural puncture headache with 27G Quincke & Whitacre needles in obstetrics/non obstetrics patients.

PubMed

Srivastava, Vibhu; Jindal, Parul; Sharma, J P

2010-06-01

The proposed study was carried out in the department of Anaesthesiology, Intensive care & Pain management, Himalayan Institute of Medical Sciences. Swami Rama Nagar, Dehradun. A total of 120 patients of ASA I & II obstetric & non-obstetric undergoing elective/emergency surgery under subarachnoid block were included under the study. To evaluate the frequency of PDPH during spinal anaesthesia using 27 gauge Quincke vs 27G whitacre needle in obstetric/non obstetric patient. In our study patients were in the age group of 15-75 years. Most of the patients in our study belong to ASA Grade I. There was 2%, 1%, 4% and 3% hypotension in-group A, B, C, D respectively. There was 2%, 4% shivering in-group A, C respectively and 1% each in group B, D. In our study failed spinal with 27G Quincke needle was in one case (3.33%) in-group C where successful subarachnoid was performed with a thicken spinal needle 23G Quincke. There was no incidence of PDPH in-group A and D, while 1 (2%) patient in-group B and 2 (4%) in group C. All the three patients were for lower section caesarean section and were young and had undergone more than one attempt to perform spinal block. The headache severity was from mild to moderate and no epidural blood patch was applied.

Methods for magnetic resonance analysis using magic angle technique

DOEpatents

Hu, Jian Zhi [Richland, WA; Wind, Robert A [Kennewick, WA; Minard, Kevin R [Kennewick, WA; Majors, Paul D [Kennewick, WA

2011-11-22

Methods of performing a magnetic resonance analysis of a biological object are disclosed that include placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. In particular embodiments the method includes pulsing the radio frequency to provide at least two of a spatially selective read pulse, a spatially selective phase pulse, and a spatially selective storage pulse. Further disclosed methods provide pulse sequences that provide extended imaging capabilities, such as chemical shift imaging or multiple-voxel data acquisition.

Wide-angle, polarization-insensitive and broadband absorber based on eight-fold symmetric SRRs metamaterial

NASA Astrophysics Data System (ADS)

Wu, Dong; Liu, Yumin; Yu, Zhongyuan; Chen, Lei; Ma, Rui; Li, Yutong; Li, Ruifang; Ye, Han

2016-12-01

In this paper, we propose a novel three dimensional metamaterial design with eight-fold rotational symmetry that shows a polarization-insensitive, wide-angle and broadband perfect absorption in the microwave band. By simulation, the polarization-insensitive absorption is over 90% between 26.9 GHz to 32.9 GHz, and the broadband absorption remains a good absorption performance to a wide incident angles for both TE and TM polarizations. The magnetic field distribution are investigated to interpret the physical mechanism of broadband absorption. The broadband absorption is based on overlapping the multiple magnetic resonances at the neighboring frequencies by coupling effects of multiple metallic split-ring resonators (SRRs). Moreover, it is demonstrate that the designed structure can be extended to other frequencies by scale down the size of the unit cell, such as the visible frequencies. The simulated results show that the absorption of the smaller absorber is above 90% in the frequency range from 467 THz to 765 THz(392-642 nm), which include orange to purple light in visible region(400-760nm). The wide-angle and polarization-insensitive stabilities of the smaller absorber is also demonstrated at visible region. The proposed work provides a new design of realization of a polarization-insensitive, wide-angle and broadband absorber ranging different frequency bands, and such a structure has potential application in the fields of solar cell, imaging and detection.

Linkage between canopy water storage and drop size distributions of leaf drips

NASA Astrophysics Data System (ADS)

Nanko, Kazuki; Watanabe, Ai; Hotta, Norifumi; Suzuki, Masakazu

2013-04-01

Differences in drop size distribution (DSD) of leaf drips among tree species have been estimated and physically interpreted to clarify the leaf drip generation process. Leaf drip generation experiments for nine species were conducted in an indoor location without foliage vibration using an automatic mist spray. Broad-leaved species produced a similar DSD among species whose leaves had a matte surface and a second similar DSD among species whose leaves had a coated surface. The matte broad leaves produced a larger and wider range of DSDs than the coated broad leaves. Coated coniferous needles had a wider range of DSDs than the coated broad leaves and different DSDs were observed for different species. The species with shorter dense needles generated a larger DSD. The leaf drip diameter was calculated through the estimation of a state of equilibrium of a hanging drop on the leaves based on physical theory. The calculations indicated that the maximum diameter of leaf drips was determined by the contact angle, and the range of DSDs was determined by the variation in contact length and the contact diameter at the hanging points. The results revealed that leaf drip DSD changed due to variations in leaf hydrophobicity, leaf roughness, leaf geometry and leaf inclination among the different tree species. This study allows the modelization of throughfall DSD. Furthermore, it indicates the possibility of interpreting canopy water processes from canopy water storage to drainage through the contact angle and leaf drip DSD. The part of this study is published in Nanko et al. (2013, Agric. Forest. Meteorol. 169, 74-84).

Range-azimuth decouple beamforming for frequency diverse array with Costas-sequence modulated frequency offsets

NASA Astrophysics Data System (ADS)

Wang, Zhe; Wang, Wen-Qin; Shao, Huaizong

2016-12-01

Different from the phased-array using the same carrier frequency for each transmit element, the frequency diverse array (FDA) uses a small frequency offset across the array elements to produce range-angle-dependent transmit beampattern. FDA radar provides new application capabilities and potentials due to its range-dependent transmit array beampattern, but the FDA using linearly increasing frequency offsets will produce a range and angle coupled transmit beampattern. In order to decouple the range-azimuth beampattern for FDA radar, this paper proposes a uniform linear array (ULA) FDA using Costas-sequence modulated frequency offsets to produce random-like energy distribution in the transmit beampattern and thumbtack transmit-receive beampattern. In doing so, the range and angle of targets can be unambiguously estimated through matched filtering and subspace decomposition algorithms in the receiver signal processor. Moreover, random-like energy distributed beampattern can also be utilized for low probability of intercept (LPI) radar applications. Numerical results show that the proposed scheme outperforms the standard FDA in focusing the transmit energy, especially in the range dimension.

Uniting Superhydrophobic, Superoleophobic and Lubricant Infused Slippery Behavior on Copper Oxide Nano-structured Substrates

PubMed Central

Ujjain, Sanjeev Kumar; Roy, Pritam Kumar; Kumar, Sumana; Singha, Subhash; Khare, Krishnacharya

2016-01-01

Alloys, specifically steel, are considered as the workhorse of our society and are inimitable engineering materials in the field of infrastructure, industry and possesses significant applications in our daily life. However, creating a robust synthetic metallic surface that repels various liquids has remained extremely challenging. The wettability of a solid surface is known to be governed by its geometric nano-/micro structure and the chemical composition. Here, we are demonstrating a facile and economical way to generate copper oxide micro-nano structures with spherical (0D), needle (1D) and hierarchical cauliflower (3D) morphologies on galvanized steel substrates using a simple chemical bath deposition method. These nano/micro textured steel surfaces, on subsequent coating of a low surface energy material display excellent superhydrophobic, superoleophobic and slippery behavior. Polydimethylsiloxane coated textured surfaces illustrate superhydrophobicity with water contact angle about 160°(2) and critical sliding angle ~2°. When functionalized with low-surface energy perfluoroalkylsilane, these surfaces display high repellency for low surface tension oils as well as hydrocarbons. Among them, the hierarchical cauliflower morphology exhibits re-entrant structure thereby showing the best superoleophobicity with contact angle 149° for dodecane. Once infused with a lubricant like silicone oil, they show excellent slippery behavior with low contact angle hysteresis (~ 2°) for water drops. PMID:27752098

Uniting Superhydrophobic, Superoleophobic and Lubricant Infused Slippery Behavior on Copper Oxide Nano-structured Substrates

NASA Astrophysics Data System (ADS)

Ujjain, Sanjeev Kumar; Roy, Pritam Kumar; Kumar, Sumana; Singha, Subhash; Khare, Krishnacharya

2016-10-01

Alloys, specifically steel, are considered as the workhorse of our society and are inimitable engineering materials in the field of infrastructure, industry and possesses significant applications in our daily life. However, creating a robust synthetic metallic surface that repels various liquids has remained extremely challenging. The wettability of a solid surface is known to be governed by its geometric nano-/micro structure and the chemical composition. Here, we are demonstrating a facile and economical way to generate copper oxide micro-nano structures with spherical (0D), needle (1D) and hierarchical cauliflower (3D) morphologies on galvanized steel substrates using a simple chemical bath deposition method. These nano/micro textured steel surfaces, on subsequent coating of a low surface energy material display excellent superhydrophobic, superoleophobic and slippery behavior. Polydimethylsiloxane coated textured surfaces illustrate superhydrophobicity with water contact angle about 160°(2) and critical sliding angle ~2°. When functionalized with low-surface energy perfluoroalkylsilane, these surfaces display high repellency for low surface tension oils as well as hydrocarbons. Among them, the hierarchical cauliflower morphology exhibits re-entrant structure thereby showing the best superoleophobicity with contact angle 149° for dodecane. Once infused with a lubricant like silicone oil, they show excellent slippery behavior with low contact angle hysteresis (~ 2°) for water drops.

Orientation Dependence of Columnar Dendritic Growth with Sidebranching Behaviors in Directional Solidification: Insights from Phase-Field Simulations

NASA Astrophysics Data System (ADS)

Xing, Hui; Dong, Xianglei; Wang, Jianyuan; Jin, Kexin

2018-04-01

In this study, a thin-interface phase-field model was employed to study the orientation dependence of the columnar dendritic growth with sidebranching behaviors in directional solidification. It was found that the dimensionless tip undercooling increases with the increase of misorientation angle for three pulling velocities. The primary spacing is found to be a function of misorientation angle, and the dimensionless primary spacing with respect to the misorientation angle follows the orientation correction given by Gandin and Rappaz (Acta. Metall. 42:2233-2246, 1994). For the analysis of the dendritic tip, the two-dimensional (2-D) form of the nonaxisymmetric needle crystal was used to determine the radius of the tilted columnar dendrite. Based on the definitions of open side and constrained side of the dendrite, the analysis of the width active sidebranches and the dendritic area in 2-D with respect to the distance from the dendritic tip was carried out to investigate the asymmetrical dendrite envelop and sidebranching behaviors on the two sides in directional solidification. The obtained prefactor and exponent with respect to misorientation angle are discussed, showing that the sidebranching behaviors of a tilted columnar dendritic array obey a similar power-law relationship with that of a free dendritic growth.

Brain activation in parietal area during manipulation with a surgical robot simulator.

PubMed

Miura, Satoshi; Kobayashi, Yo; Kawamura, Kazuya; Nakashima, Yasutaka; Fujie, Masakatsu G

2015-06-01

we present an evaluation method to qualify the embodiment caused by the physical difference between master-slave surgical robots by measuring the activation of the intraparietal sulcus in the user's brain activity during surgical robot manipulation. We show the change of embodiment based on the change of the optical axis-to-target view angle in the surgical simulator to change the manipulator's appearance in the monitor in terms of hand-eye coordination. The objective is to explore the change of brain activation according to the change of the optical axis-to-target view angle. In the experiments, we used a functional near-infrared spectroscopic topography (f-NIRS) brain imaging device to measure the brain activity of the seven subjects while they moved the hand controller to insert a curved needle into a target using the manipulator in a surgical simulator. The experiment was carried out several times with a variety of optical axis-to-target view angles. Some participants showed a significant peak (P value = 0.037, F-number = 2.841) when the optical axis-to-target view angle was 75°. The positional relationship between the manipulators and endoscope at 75° would be the closest to the human physical relationship between the hands and eyes.

Ring magnet firing angle control

DOEpatents

Knott, M.J.; Lewis, L.G.; Rabe, H.H.

1975-10-21

A device is provided for controlling the firing angles of thyratrons (rectifiers) in a ring magnet power supply. A phase lock loop develops a smooth ac signal of frequency equal to and in phase with the frequency of the voltage wave developed by the main generator of the power supply. A counter that counts from zero to a particular number each cycle of the main generator voltage wave is synchronized with the smooth AC signal of the phase lock loop. Gates compare the number in the counter with predetermined desired firing angles for each thyratron and with coincidence the proper thyratron is fired at the predetermined firing angle.

AC electrical breakdown phenomena of epoxy/layered silicate nanocomposite in needle-plate electrodes.

PubMed

Park, Jae-Jun; Lee, Jae-Young

2013-05-01

Epoxy/layered silicate nanocomposite for the insulation of heavy electric equipments were prepared by dispersing 1 wt% of a layered silicate into an epoxy matrix with a homogenizing mixer and then AC electrical treeing and breakdown tests were carried out. Wide-angle X-ray diffraction (WAXD) analysis and transmission electron microscopy (TEM) observation showed that nano-sized monolayers were exfoliated from a multilayered silicate in the epoxy matrix. When the nano-sized silicate layers were incorporated into the epoxy matrix, the breakdown rate in needle-plate electrode geometry was 10.6 times lowered than that of the neat epoxy resin under the applied electrical field of 520.9 kV/mm at 30 degrees C, and electrical tree propagated with much more branches in the epoxy/layered silicate nanocomposite. These results showed that well-dispersed nano-sized silicate layers retarded the electrical tree growth rate. The effects of applied voltage and ambient temperature on the tree initiation, growth, and breakdown rate were also studied, and it was found that the breakdown rate was largely increased, as the applied voltage and ambient temperature increased.

Fate of Lu(III) sorbed on 2-line ferrihydrite at pH 5.7 and aged for 12 years at room temperature. II: insights from STEM-EDXS and DFT calculations.

PubMed

Yokosawa, Tadahiro; Prestat, Eric; Polly, Robert; Bouby, Muriel; Dardenne, Kathy; Finck, Nicolas; Haigh, Sarah J; Denecke, Melissa A; Geckeis, Horst

2018-04-18

Transformation products of two-line ferrihydrite associated with Lu(III) were studied after 12 years of aging using aberration-corrected high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), high-efficiency energy-dispersive X-ray spectroscopy (EDXS), and density functional theory (DFT). The transformation products consisted of hematite nanoparticles with overgrown goethite needles. High-efficiency STEM-EDXS revealed that Lu is only associated with goethite needles, and atomic-resolution HAADF-STEM reveals structural incorporation of Lu within goethite, partially replacing structural Fe sites. This finding corroborates those recently obtained by AsFlFFF and EXAFS spectroscopy on the same sample (Finck et al. 2018). DFT calculations indicate that Lu incorporation within goethite or hematite are almost equally likely, suggesting that experimental parameters such as temperature and reaction time which affect reaction kinetics, play important roles in determining the Lu uptake. It seems likely that these results may be transferable to predict the behavior of chemically homologous trivalent actinides.

Tips on robotic single-site surgery suture technique: Screwing and clockwise direction suture technique for Robotic single-site surgery.

PubMed

Moon, Hye-Sung

2018-06-01

Using the da Vinci single-site platform, surgeons can perform more minimally invasive surgery. However, surgical challenges exist due to the limitations of single-site instrumental movements. To aid in the performance of successful robotic single-site hysterectomy, a new suturing technique using the current set of limited instruments is introduced in this study. New vaginal cuff suturing techniques have been used in 55 robotic single-site hysterectomies in our institute over the past 2 years. A needle driver approach utilizing screwing and advancing the needle driver in the correct direction at an increasing angle from the transverse cuff margin with dragging and formation of an adequate loop of thread was used when suturing the vaginal cuff. Using the new vaginal suturing techniques, easy and firm vaginal cuff closure with reduced operative time relative to previous hysterectomies was achieved. The new vaginal cuff suturing techniques may convince more surgeons to perform robotic single-site hysterectomies more frequently and with greater ease. Copyright © 2018. Published by Elsevier B.V.

HIFU Transducer Characterization Using a Robust Needle Hydrophone

NASA Astrophysics Data System (ADS)

Howard, Samuel M.; Zanelli, Claudio I.

2007-05-01

A robust needle hydrophone has been developed for HIFU transducer characterization and reported on earlier. After a brief review of the hydrophone design and performance, we demonstrate its use to characterize a 1.5 MHz, 10 cm diameter, F-number 1.5 spherically focused source driven to exceed an intensity of 1400 W/cm2at its focus. Quantitative characterization of this source at high powers is assisted by deconvolving the hydrophone's calibrated frequency response in order to accurately reflect the contribution of harmonics generated by nonlinear propagation in the water testing environment. Results are compared to measurements with a membrane hydrophone at 0.3% duty cycle and to theoretical calculations, using measurements of the field at the source's radiating surface as input to a numerical solution of the KZK equation.

Tissue characterization using electrical impedance spectroscopy data: a linear algebra approach.

PubMed

Laufer, Shlomi; Solomon, Stephen B; Rubinsky, Boris

2012-06-01

In this study, we use a new linear algebra manipulation on electrical impedance spectroscopy measurements to provide real-time information regarding the nature of the tissue surrounding the needle in minimal invasive procedures. Using a Comsol Multiphysics three-dimensional model, a phantom based on ex vivo animal tissue and in vivo animal data, we demonstrate how tissue inhomogeneity can be characterized without any previous knowledge of the electrical properties of the different tissues, except that they should not be linearly dependent on a certain frequency range. This method may have applications in needle biopsies, radiation seeds, or minimally invasive surgery and can reduce the number of computer tomography or magnetic resonance imaging images. We conclude by demonstrating how this mathematical approach can be useful in other applications.

A statistical model for combustion resonance from a DI diesel engine with applications

NASA Astrophysics Data System (ADS)

Bodisco, Timothy; Low Choy, Samantha; Masri, Assaad; Brown, Richard J.

2015-08-01

Introduced in this paper is a Bayesian model for isolating the resonant frequency from combustion chamber resonance. The model shown in this paper focused on characterising the initial rise in the resonant frequency to investigate the rise of in-cylinder bulk temperature associated with combustion. By resolving the model parameters, it is possible to determine: the start of pre-mixed combustion, the start of diffusion combustion, the initial resonant frequency, the resonant frequency as a function of crank angle, the in-cylinder bulk temperature as a function of crank angle and the trapped mass as a function of crank angle. The Bayesian method allows for individual cycles to be examined without cycle-averaging-allowing inter-cycle variability studies. Results are shown for a turbo-charged, common-rail compression ignition engine run at 2000 rpm and full load.

A single-layer wide-angle negative-index metamaterial at visible frequencies.

PubMed

Burgos, Stanley P; de Waele, Rene; Polman, Albert; Atwater, Harry A

2010-05-01

Metamaterials are materials with artificial electromagnetic properties defined by their sub-wavelength structure rather than their chemical composition. Negative-index materials (NIMs) are a special class of metamaterials characterized by an effective negative index that gives rise to such unusual wave behaviour as backwards phase propagation and negative refraction. These extraordinary properties lead to many interesting functions such as sub-diffraction imaging and invisibility cloaking. So far, NIMs have been realized through layering of resonant structures, such as split-ring resonators, and have been demonstrated at microwave to infrared frequencies over a narrow range of angles-of-incidence and polarization. However, resonant-element NIM designs suffer from the limitations of not being scalable to operate at visible frequencies because of intrinsic fabrication limitations, require multiple functional layers to achieve strong scattering and have refractive indices that are highly dependent on angle of incidence and polarization. Here we report a metamaterial composed of a single layer of coupled plasmonic coaxial waveguides that exhibits an effective refractive index of -2 in the blue spectral region with a figure-of-merit larger than 8. The resulting NIM refractive index is insensitive to both polarization and angle-of-incidence over a +/-50 degree angular range, yielding a wide-angle NIM at visible frequencies.

Electron Scattering by High-Frequency Whistler Waves at Earth's Bow Shock

NASA Technical Reports Server (NTRS)

Oka, M.; Wilson, L. B., III; Phan, T. D.; Hull, A. J.; Amano, T.; Hoshino, M.; Argall, M. R.; Le Contel, O.; Agapitov, O.; Gersham, D. J.;

Electron Scattering by High-frequency Whistler Waves at Earth’s Bow Shock

NASA Astrophysics Data System (ADS)

Oka, M.; Wilson, L. B., III; Phan, T. D.; Hull, A. J.; Amano, T.; Hoshino, M.; Argall, M. R.; Le Contel, O.; Agapitov, O.; Gershman, D. J.; Khotyaintsev, Y. V.; Burch, J. L.; Torbert, R. B.; Pollock, C.; Dorelli, J. C.; Giles, B. L.; Moore, T. E.; Saito, Y.; Avanov, L. A.; Paterson, W.; Ergun, R. E.; Strangeway, R. J.; Russell, C. T.; Lindqvist, P. A.

2017-06-01

Electrons are accelerated to non-thermal energies at shocks in space and astrophysical environments. While different mechanisms of electron acceleration have been proposed, it remains unclear how non-thermal electrons are produced out of the thermal plasma pool. Here, we report in situ evidence of pitch-angle scattering of non-thermal electrons by whistler waves at Earth’s bow shock. On 2015 November 4, the Magnetospheric Multiscale (MMS) mission crossed the bow shock with an Alfvén Mach number ˜11 and a shock angle ˜84°. In the ramp and overshoot regions, MMS revealed bursty enhancements of non-thermal (0.5-2 keV) electron flux, correlated with high-frequency (0.2-0.4 {{{Ω }}}{ce}, where {{{Ω }}}{ce} is the cyclotron frequency) parallel-propagating whistler waves. The electron velocity distribution (measured at 30 ms cadence) showed an enhanced gradient of phase-space density at and around the region where the electron velocity component parallel to the magnetic field matched the resonant energy inferred from the wave frequency range. The flux of 0.5 keV electrons (measured at 1 ms cadence) showed fluctuations with the same frequency. These features indicate that non-thermal electrons were pitch-angle scattered by cyclotron resonance with the high-frequency whistler waves. However, the precise role of the pitch-angle scattering by the higher-frequency whistler waves and possible nonlinear effects in the electron acceleration process remains unclear.

Individual Optimal Frequency in Whole-Body Vibration: Effect of Protocol, Joint Angle, and Fatiguing Exercise.

PubMed

Carlucci, Flaminia; Felici, Francesco; Piccinini, Alberto; Haxhi, Jonida; Sacchetti, Massimo

2016-12-01

Carlucci, F, Felici, F, Piccinini, A, Haxhi, J, and Sacchetti, M. Individual optimal frequency in whole-body vibration: effect of protocol, joint angle, and fatiguing exercise. J Strength Cond Res 30(12): 3503-3511, 2016-Recent studies have shown the importance of individualizing the vibration intervention to produce greater effects on the neuromuscular system in less time. The purpose of this study was to assess the individual optimal vibration frequency (OVF) corresponding to the highest muscle activation (RMSmax) during vibration at different frequencies, comparing different protocols. Twenty-nine university students underwent 3 continuous (C) and 2 random (R) different vibrating protocols, maintaining a squat position on a vibration platform. The C protocol lasted 50 seconds and involved the succession of ascending frequencies from 20 to 55 Hz, every 5 seconds. The same protocol was performed twice, having the knee angle at 120° (C) and 90° (C90), to assess the effect of joint angle and after a fatiguing squatting exercise (CF) to evaluate the influence of fatigue on OVF assessment. In the random protocols, vibration time was 20 seconds with a 2-minute (R2) and a 4-minute (R4) pauses between tested frequencies. Muscle activation and OVF values did not differ significantly in the C, R2, and R4 protocols. RMSmax was higher in C90 (p < 0.001) and in CF (p = 0.04) compared with the C protocol. Joint angle and fatiguing exercise had no effect on OVF. In conclusion, the shorter C protocol produced similar myoelectrical activity in the R2 and the R4 protocols, and therefore, it could be equally valid in identifying the OVF with considerable time efficiency. Knee joint angle and fatiguing exercise had an effect on surface electromyography response during vibration but did not affect OVF identification significantly.

Design and analysis of all-dielectric broadband nonpolarizing parallel-plate beam splitters.

PubMed

Wang, Wenliang; Xiong, Shengming; Zhang, Yundong

2007-06-01

Past research on the all-dielectric nonpolarizing beam splitter is reviewed. With the aid of the needle thin-film synthesis method and the conjugate graduate refine method, three different split ratio nonpolarizing parallel-plate beam splitters over a 200 nm spectral range centered at 550 nm with incidence angles of 45 degrees are designed. The chosen materials component and the initial stack are based on the Costich and Thelen theories. The results of design and analysis show that the designs maintain a very low polarization ratio in the working range of the spectrum and has a reasonable angular field.

All-dielectric broadband non-polarizing parallel plate beam splitter operating between 450-650nm

NASA Astrophysics Data System (ADS)

Wang, Wenliang; Xiong, Shenming; Zhang, Yundong

2007-12-01

Past research on all-dielectric non-polarizing beam splitter is reviewed. With the aid of needle thin film synthesis method and conjugate graduate refining method, three non-polarizing parallel plate beam splitters with different split ratios over a 200nm spectral range centered at 550nm with incidence angle 45° are designed. Selection of material components and initial stack are based on Costich and Thelen's theory. The results of design and analysis show that it maintains a very low polarization ratio in the working range of spectrum and has a reasonable angular field.

Small-molecule type III secretion system inhibitors block assembly of the Shigella type III secreton.

PubMed

Veenendaal, Andreas K J; Sundin, Charlotta; Blocker, Ariel J

2009-01-01

Type III secretion systems (T3SSs) are essential virulence devices for many gram-negative bacteria that are pathogenic for plants, animals, and humans. They serve to translocate virulence effector proteins directly into eukaryotic host cells. T3SSs are composed of a large cytoplasmic bulb and a transmembrane region into which a needle is embedded, protruding above the bacterial surface. The emerging antibiotic resistance of bacterial pathogens urges the development of novel strategies to fight bacterial infections. Therapeutics that rather than kill bacteria only attenuate their virulence may reduce the frequency or progress of resistance emergence. Recently, a group of salicylidene acylhydrazides were identified as inhibitors of T3SSs in Yersinia, Chlamydia, and Salmonella species. Here we show that these are also effective on the T3SS of Shigella flexneri, where they block all related forms of protein secretion so far known, as well as the epithelial cell invasion and induction of macrophage apoptosis usually demonstrated by this bacterium. Furthermore, we show the first evidence for the detrimental effect of these compounds on T3SS needle assembly, as demonstrated by increased numbers of T3S apparatuses without needles or with shorter needles. Therefore, the compounds generate a phenocopy of T3SS export apparatus mutants but with incomplete penetrance. We discuss why this would be sufficient to almost completely block the later secretion of effector proteins and how this begins to narrow the search for the molecular target of these compounds.

Properties of seismic absorption induced reflections

NASA Astrophysics Data System (ADS)

Zhao, Haixia; Gao, Jinghuai; Peng, Jigen

2018-05-01

Seismic reflections at an interface are often regarded as the variation of the acoustic impedance (product of seismic velocity and density) in a medium. In fact, they can also be generated due to the difference in absorption of the seismic energy. In this paper, we investigate the properties of such reflections. Based on the diffusive-viscous wave equation and elastic diffusive-viscous wave equation, we investigate the dependency of the reflection coefficients on frequency, and their variations with incident angles. Numerical results at a boundary due to absorption contrasts are compared with those resulted from acoustic impedance variation. It is found that, the reflection coefficients resulted from absorption depend significantly on the frequency especially at lower frequencies, but vary very slowly at small incident angles. At the higher frequencies, the reflection coefficients of diffusive-viscous wave and elastic diffusive-viscous wave are close to those of acoustic and elastic cases, respectively. On the other hand, the reflections caused by acoustic impedance variation are independent of frequency but vary distinctly with incident angles before the critical angle. We also investigate the difference between the seismograms generated in the two different media. The numerical results show that the amplitudes of these reflected waves are attenuated and their phases are shifted. However, the reflections obtained by acoustic impedance contrast, show no significant amplitude attenuation and phase shift.

The Frequency of Optical Coherence Tomography Testing in Glaucoma at a Single Academic Medical Center.

PubMed

Griffith, Joseph F; Goldberg, Jeffrey L

2016-03-01

To determine the frequency of optical coherence tomography (OCT) examinations compared with clinical examinations and visual field (VF) tests in patients with 5 types of glaucoma. A retrospective, longitudinal cohort study was conducted of 5154 patients treated between 2003 and 2010 at a single academic medical center. Patients were classified using billing records as having primary open-angle glaucoma, low-tension open-angle glaucoma (NTG), pigmentary open-angle glaucoma, chronic angle-closure glaucoma, or pseudoexfoliation glaucoma. Analysis of variance, χ test, and exact χ test were performed to identify associations between glaucoma type and test frequency. Pigmentary open-angle glaucoma and NTG patients had a higher rate of undergoing at least 2 VFs (94.4%, 94.9%), and chronic angle-closure glaucoma patients had a lower rate of undergoing at least 2 OCTs (25.3%) than all other glaucoma types. NTG patients also had the highest rate of undergoing at least 2 OCTs and at least 2 VFs (36.6%). Overall, the rate of clinical examinations (2.68 examinations/y) exceeded the rates of OCTs (1.39 examinations/y), which exceeded the rate of VF tests (1.24 tests/y). There were no differences in OCT frequency between glaucoma types (0.91 to 1.63 OCTs/y). Within each glaucoma diagnosis, patients had clinical examinations more frequently than OCTs and clinical examinations more frequently than VFs. Primary open-angle glaucoma and pseudoexfoliation glaucoma patients also had OCTs more frequently than VFs. More patients had at least 2 VF tests than at least 2 OCTs (4481 vs. 1679). The relative use of clinical examinations, VF testing, and OCT imaging varies among glaucoma diagnoses.

Initial clinical experience with a quadrupole butterfly coil for spinal injection interventions in an open MRI system at 1.0 tesla.

PubMed

Jonczyk, Martin; Hamm, Bernd; Heinrich, Andreas; Thomas, Andreas; Rathke, Hendrik; Schnackenburg, Bernhard; Güttler, Felix; Teichgräber, Ulf K M; de Bucourt, Maximilian

2014-02-01

To report our initial clinical experience with a new magnetic resonance imaging (MRI) quadrupole coil that allows interventions in prone position. Fifteen patients (seven women, eight men; average age, 42.8 years) were treated in the same 1.0-Tesla Panorama High Field Open (HFO) MRI system (Panorama HFO) using a quadrupole butterfly coil (Bfly) and compared with 15 patients matched for sex, age, and MR intervention using the MultiPurposeL coil (MPL), performed in conventional lateral decubitus position (all, Philips Medical Systems, Best, The Netherlands). All interventions were performed with a near-real-time proton density turbo spin echo (PD TSE) sequence (time to repeat/time to echo/flip angle/acquisition time, 600 ms/10 ms/90°/3 s/image). Qualitative and quantitative image analyses were performed, including signal intensity, signal-to-noise and contrast-to-noise ratio (SNR, CNR), contrast, and full width at half maximum (FWHM) measurements. Contrast differed significantly between the needle and muscles (Bfly 0.27/MPL 0.17), as well as the needle and periradicular fat (0.13/0.24) during the intervention (both, p=0.029), as well as the CNR between muscles and the needle (10.61/5.23; p=0.010), although the FWHM values did not (2.4/2.2; p=0.754). The signal intensity of the needle in interventional imaging (1152.9/793.2; p=0.006) and the postinterventional SNR values of subcutaneous fat (15.3/28.6; p=0.007), muscles (6.6/11.8; p=0.011), and the CNR between these tissues (8.7/17.5; p=0.004) yielded significant differences. The new coil is a valid alternative for MR-guided interventions in an open MRI system at 1.0 tesla, especially if patients cannot (or prefer not to) be in a lateral decubitus position or if prone positioning yields better access to the target zone.

Double-quantum homonuclear rotary resonance: Efficient dipolar recovery in magic-angle spinning nuclear magnetic resonance

NASA Astrophysics Data System (ADS)

Nielsen, N. C.; Bildsøe, H.; Jakobsen, H. J.; Levitt, M. H.

1994-08-01

We describe an efficient method for the recovery of homonuclear dipole-dipole interactions in magic-angle spinning NMR. Double-quantum homonuclear rotary resonance (2Q-HORROR) is established by fulfilling the condition ωr=2ω1, where ωr is the sample rotation frequency and ω1 is the nutation frequency around an applied resonant radio frequency (rf) field. This resonance can be used for double-quantum filtering and measurement of homonuclear dipolar interactions in the presence of magic-angle spinning. The spin dynamics depend only weakly on crystallite orientation allowing good performance for powder samples. Chemical shift effects are suppressed to zeroth order. The method is demonstrated for singly and doubly 13C labeled L-alanine.

On the viewing angle dependence of blazar variability

NASA Astrophysics Data System (ADS)

Eldar, Avigdor; Levinson, Amir

2000-05-01

Internal shocks propagating through an ambient radiation field are subject to a radiative drag that, under certain conditions, can significantly affect their dynamics, and consequently the evolution of the beaming cone of emission produced behind the shocks. The resultant change of the Doppler factor combined with opacity effects leads to a strong dependence on the viewing angle of the variability pattern produced by such systems; specifically, the shape of the light curves and the characteristics of correlated emission. One implication is that objects oriented at relatively large viewing angles to the observer should exhibit a higher level of activity at high synchrotron frequencies (above the self-absorption frequency), and also at gamma-ray energies below the threshold energy of pair production, than at lower (radio/millimetre) frequencies.

Finding Needles in Haystacks: Identity Mismatch Frequency and Facial Identity Verification

ERIC Educational Resources Information Center

Bindemann, Markus; Avetisyan, Meri; Blackwell, Kristy-Ann

2010-01-01

Accurate person identification is central to all security, police, and judicial systems. A commonplace method to achieve this is to compare a photo-ID and the face of its purported owner. The critical aspect of this task is to spot cases in which these two instances of a face do not match. Studies of person identification show that these instances…

Investigation of Gas Holdup in a Vibrating Bubble Column

NASA Astrophysics Data System (ADS)

Mohagheghian, Shahrouz; Elbing, Brian

2015-11-01

Synthetic fuels are part of the solution to the world's energy crisis and climate change. Liquefaction of coal during the Fischer-Tropsch process in a bubble column reactor (BCR) is a key step in production of synthetic fuel. It is known from the 1960's that vibration improves mass transfer in bubble column. The current study experimentally investigates the effect that vibration frequency and amplitude has on gas holdup and bubble size distribution within a bubble column. Air (disperse phase) was injected into water (continuous phase) through a needle shape injector near the bottom of the column, which was open to atmospheric pressure. The air volumetric flow rate was measured with a variable area flow meter. Vibrations were generated with a custom-made shaker table, which oscillated the entire column with independently specified amplitude and frequency (0-30 Hz). Geometric dependencies can be investigated with four cast acrylic columns with aspect ratios ranging from 4.36 to 24, and injector needle internal diameters between 0.32 and 1.59 mm. The gas holdup within the column was measured with a flow visualization system, and a PIV system was used to measure phase velocities. Preliminary results for the non-vibrating and vibrating cases will be presented.

DSS 15, 45, and 65 34-meter high efficiency antenna radio frequency performance enhancement by tilt added to the subreflector during elevation angle changes

NASA Technical Reports Server (NTRS)

Katow, M. S.

1990-01-01

The focusing adjustments of the subreflectors of an az-el Cassegrainian antenna that uses only linear motions have always ended in lateral offsets of the phase centers at the subreflector's focus points at focused positions, which have resulted in small gain losses. How lateral offsets at the two focus points were eliminated by tilting the subreflector, resulting in higher radio frequency (RF) efficiencies at all elevation angles rotated from the rigging angles are described.

Modeling of layered anisotropic composite material based on effective medium theory

NASA Astrophysics Data System (ADS)

Bao, Yang; Song, Jiming

2018-04-01

In this paper, we present an efficient method to simulate multilayered anisotropic composite material with effective medium theory. Effective permittivity, permeability and orientation angle for a layered anisotropic composite medium are extracted with this equivalent model. We also derive analytical expressions for effective parameters and orientation angle with low frequency (LF) limit, which will be shown in detail. Numerical results are shown in comparing extracted effective parameters and orientation angle with analytical results from low frequency limit. Good agreements are achieved to demonstrate the accuracy of our efficient model.

Comparative evaluation of postoperative pain after using endodontic needle and EndoActivator during root canal irrigation: A randomised controlled trial.

PubMed

Ramamoorthi, Surendar; Nivedhitha, Malli Sureshbabu; Divyanand, Madras Jeyaprakash

2015-08-01

The purpose of this study was to evaluate and compare the postoperative level of pain after activation of irrigants using EndoActivator with conventional needle irrigation during root canal therapy. In this prospective randomised clinical trial, 72 symptomatic irreversible pulpitis patients were selected. Based on block randomisation after routine root canal preparation, patients were assigned to two groups. In group EN, procedures were performed with endodontic irrigating needle (n = 36) while group EA received activation using EndoActivator (n = 36) in the final irrigation protocol. All the participants were called through phone at 8, 24 and 48 h to analyse pain score using visual analogue scale. Those patients who developed pain were prescribed ibuprofen 200 mg. Pain score and frequency of tablet intake were recorded and statistically analysed. Results showed that group EA resulted in significantly less postoperative pain and analgesics intake than group EN. In conclusion, within the limitations of this study, the activation of irrigants using EndoActivator can be considered an effective method for reducing postoperative pain. © 2014 Australian Society of Endodontology.

Frequency-dependent polarization-angle-phase-shift in the microwave-induced magnetoresistance oscillations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Han-Chun; Ye, Tianyu; Mani, R. G.

2015-02-14

Linear polarization angle, θ, dependent measurements of the microwave radiation-induced oscillatory magnetoresistance, R{sub xx}, in high mobility GaAs/AlGaAs 2D electron devices have shown a θ dependence in the oscillatory amplitude along with magnetic field, frequency, and extrema-dependent phase shifts, θ{sub 0}. Here, we suggest a microwave frequency dependence of θ{sub 0}(f) using an analysis that averages over other smaller contributions, when those contributions are smaller than estimates of the experimental uncertainty.

Needle Biopsy

MedlinePlus

... needle biopsy procedures include fine-needle aspiration and core needle biopsy. Needle biopsy may be used to ... hollow needle to draw cells from your body. Core needle biopsy. This type of needle biopsy uses ...

Ongoing incident hepatitis C virus infection among people with a history of injecting drug use in an Australian prison setting, 2005-2014: The HITS-p study.

PubMed

Cunningham, E B; Hajarizadeh, B; Bretana, N A; Amin, J; Betz-Stablein, B; Dore, G J; Luciani, F; Teutsch, S; Dolan, K; Lloyd, A R; Grebely, J

2017-09-01

Hepatitis C virus (HCV) transmission is high in prisons. This study investigated trends in HCV incidence and associated factors among a cohort of prisoners with a history of injecting drug use in New South Wales, Australia. Data were available from the Hepatitis C Incidence and Transmission Study-prisons (HITS-p) from 2005 to 2014. Temporal trends in HCV incidence were evaluated. Factors associated with time to HCV seroconversion among people with ongoing injecting was assessed using Cox proportional hazards. Among 320 antibody-negative participants with a history of injecting drug use (mean age 26; 72% male), 62% (n=197) reported injecting drug use during follow-up. Overall, 93 infections were observed. HCV incidence was 11.4/100 person-years in the overall population and 6.3/100 person-years among the continually imprisoned population. A stable trend in HCV incidence was observed. Among the overall population with ongoing injecting during follow-up, ≥weekly injecting drug use frequency was independently associated with time to HCV seroconversion. Among continuously imprisoned injectors with ongoing injecting during follow-up, needle/syringe sharing was independently associated with time to HCV seroconversion. This study demonstrates that prison is a high-risk environment for acquisition of HCV infection. Needle and syringe sharing was associated with HCV infection among continually imprisoned participants, irrespective of frequency of injecting or the type of drug injected. These findings highlight the need for the evaluation of improved HCV prevention strategies in prison, including needle/syringe programmes and HCV treatment. © 2017 John Wiley & Sons Ltd.

A Two-Dimensional Micro Scanner Integrated with a Piezoelectric Actuator and Piezoresistors

PubMed Central

Zhang, Chi; Zhang, Gaofei; You, Zheng

2009-01-01

A compact two-dimensional micro scanner with small volume, large deflection angles and high frequency is presented and the two-dimensional laser scanning is achieved by specular reflection. To achieve large deflection angles, the micro scanner excited by a piezoelectric actuator operates in the resonance mode. The scanning frequencies and the maximum scanning angles of the two degrees of freedom are analyzed by modeling and simulation of the structure. For the deflection angle measurement, piezoresistors are integrated in the micro scanner. The appropriate directions and crystal orientations of the piezoresistors are designed to obtain the large piezoresistive coefficients for the high sensitivities. Wheatstone bridges are used to measure the deflection angles of each direction independently and precisely. The scanner is fabricated and packaged with the piezoelectric actuator and the piezoresistors detection circuits in a size of 28 mm×20 mm×18 mm. The experiment shows that the two scanning frequencies are 216.8 Hz and 464.8 Hz, respectively. By an actuation displacement of 10 μm, the scanning range of the two-dimensional micro scanner is above 26° × 23°. The deflection angle measurement sensitivities for two directions are 59 mV/deg and 30 mV/deg, respectively. PMID:22389621

A two-dimensional micro scanner integrated with a piezoelectric actuator and piezoresistors.

PubMed

Zhang, Chi; Zhang, Gaofei; You, Zheng

2009-01-01

A compact two-dimensional micro scanner with small volume, large deflection angles and high frequency is presented and the two-dimensional laser scanning is achieved by specular reflection. To achieve large deflection angles, the micro scanner excited by a piezoelectric actuator operates in the resonance mode. The scanning frequencies and the maximum scanning angles of the two degrees of freedom are analyzed by modeling and simulation of the structure. For the deflection angle measurement, piezoresistors are integrated in the micro scanner. The appropriate directions and crystal orientations of the piezoresistors are designed to obtain the large piezoresistive coefficients for the high sensitivities. Wheatstone bridges are used to measure the deflection angles of each direction independently and precisely. The scanner is fabricated and packaged with the piezoelectric actuator and the piezoresistors detection circuits in a size of 28 mm×20 mm×18 mm. The experiment shows that the two scanning frequencies are 216.8 Hz and 464.8 Hz, respectively. By an actuation displacement of 10 μm, the scanning range of the two-dimensional micro scanner is above 26° × 23°. The deflection angle measurement sensitivities for two directions are 59 mV/deg and 30 mV/deg, respectively.

Anisotropy of the apparent frequency dependence of backscatter in formalin fixed human myocardium.

PubMed

Hall, C S; Verdonk, E D; Wickline, S A; Perez, J E; Miller, J G

1997-01-01

Measurements of the frequency dependence of ultrasonic backscatter are presented for specific angles of insonification for regions of infarcted and noninfarcted human myocardium. A 5-MHz transducer was used to insonify cylindrical cores taken from 7 noninfarcted regions and 12 infarcted regions of the left ventricular free wall of 6 formalin-fixed human hearts explanted because of ischemic cardiomyopathy. The dependence of apparent (uncompensated for diffraction effects and attenuation) backscatter on frequency was approximated by a power-law dependence, magnitude of B(f)2 = afn. Under ideal conditions in a lossless medium, the effect of not compensating for the effects of diffraction and attenuation leads to the value of n to be 2.0 for Rayleigh scatterers while the frequency dependence of the fully compensated backscatter coefficient would be f4. The value of n was determined over the frequency range, 3-7 MHz. Both nonifarcted and infarcted myocardium exhibited anisotropy of the frequency dependence of backscatter, with maxima occurring at angles that were perpendicular to the predominant myofiber direction and minima when parallel to the fibers. Perpendicular insonification yielded results for n of 1.8 +/- 0.1 for noninfarcted myocardium and 1.2 +/- 0.1 for infarcted myocardium while parallel insonification yielded results of 0.4 +/- 0.1 for noninfarcted and 0.0 +/- 0.1 for infarcted myocardium. The functional form of the angle-dependent backscatter is similar for both noninfarcted and infarcted myocardium, although the frequency dependence is clearly different for both tissue states for all angles of insonification. The results of this study indicate that the anisotropy of the frequency dependence of backscatter may play a significant role in ultrasonic imaging and is an important consideration for ultrasonic tissue characterization in myocardium.

Analysis of Wind Tunnel Longitudinal Static and Oscillatory Data of the F-16XL Aircraft

NASA Technical Reports Server (NTRS)

Klein, Vladislav; Murphy, Patrick C.; Curry, Timothy J.; Brandon, Jay M.

1997-01-01

Static and oscillatory wind tunnel data are presented for a 10-percent-scale model of an F-16XL aircraft. Static data include the effect of angle of attack, sideslip angle, and control surface deflections on aerodynamic coefficients. Dynamic data from small-amplitude oscillatory tests are presented at nominal values of angle of attack between 20 and 60 degrees. Model oscillations were performed at five frequencies from 0.6 to 2.9 Hz and one amplitude of 5 degrees. A simple harmonic analysis of the oscillatory data provided Fourier coefficients associated with the in-phase and out-of-phase components of the aerodynamic coefficients. A strong dependence of the oscillatory data on frequency led to the development of models with unsteady terms in the form of indicial functions. Two models expressing the variation of the in-phase and out-of-phase components with angle of attack and frequency were proposed and their parameters estimated from measured data.

Single Frequency Impedance Analysis on Reduced Graphene Oxide Screen-Printed Electrode for Biomolecular Detection.

PubMed

Rajesh; Singal, Shobhita; Kotnala, Ravinder K

2017-10-01

A biofunctionalized reduced graphene oxide (rGO)-modified screen-printed carbon electrode (SPCE) was constructed as an immunosensor for C-reactive protein (CRP) detection, a biomarker released in early stage acute myocardial infarction. A different approach of single frequency analysis (SFA) study was utilized for the biomolecular sensing, by monitoring the response in phase angle changes obtained at an optimized frequency resulting from antigen-antibody interactions. A set of measurements were carried out to optimize a frequency where a maximum change in phase angle was observed, and in this case, we found it at around 10 Hz. The bioelectrode was characterized by contact angle measurements, scanning electron microscopy, and electrochemical techniques. A concentration-dependent response of immunosensor to CRP with the change in phase angle, at a fixed frequency of 10 Hz, was found to be in the range of 10 ng mL -1 to 10 μg mL -1 in PBS and was fit quantitative well with the Hill-Langmuir equation. Based on the concentration-response data, the dissociation constant (K d ) was found to be 3.5 nM (with a Hill coefficient n = 0.57), which indicated a negative cooperativity with high anti-CRP (antibody)-CRP (antigen) binding at the electrode surface. A low-frequency analysis of sensing with an ease of measurement on a disposable electroactive rGO-modified electrode with high selectivity and sensitivity makes it a potential tool for biological sensors.

Spin-torque diode with tunable sensitivity and bandwidth by out-of-plane magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, X.; Zheng, C.; Pong, Philip W. T.

Spin-torque diodes based on nanosized magnetic tunnel junctions are novel microwave detectors with high sensitivity and wide frequency bandwidth. While previous reports mainly focus on improving the sensitivity, the approaches to extend the bandwidth are limited. This work experimentally demonstrates that through optimizing the orientation of the external magnetic field, wide bandwidth can be achieved while maintaining high sensitivity. The mechanism of the frequency- and sensitivity-tuning is investigated through analyzing the dependence of resonant frequency and DC voltage on the magnitude and the tilt angle of hard-plane magnetic field. The frequency dependence is qualitatively explicated by Kittel's ferromagnetic resonance model.more » The asymmetric resonant frequency at positive and negative magnetic field is verified by the numerical simulation considering the in-plane anisotropy. The DC voltage dependence is interpreted through evaluating the misalignment angle between the magnetization of the free layer and the reference layer. The tunability of the detector performance by the magnetic field angle is evaluated through characterizing the sensitivity and bandwidth under 3D magnetic field. The frequency bandwidth up to 9.8 GHz or maximum sensitivity up to 154 mV/mW (after impedance mismatch correction) can be achieved by tuning the angle of the applied magnetic field. The results show that the bandwidth and sensitivity can be controlled and adjusted through optimizing the orientation of the magnetic field for various applications and requirements.« less

Orbits: Computer simulation

NASA Technical Reports Server (NTRS)

Muszynska, A.

1985-01-01

In rotating machinery dynamics an orbit (Lissajous curve) represents the dynamic path of the shaft centerline motion during shaft rotation and resulting precession. The orbit can be observed with an oscilloscope connected to XY promixity probes. The orbits can also be simulated by a computer. The software for HP computer simulates orbits for two cases: (1) Symmetric orbit with four frequency components with different radial amplitudes and relative phase angles; and (2) Nonsymmetric orbit with two frequency components with two different vertical/horizontal amplitudes and two different relative phase angles. Each orbit carries a Keyphasor mark (one-per-turn reference). The frequencies, amplitudes, and phase angles, as well as number of time steps for orbit computation, have to be chosen and introduced to the computer by the user. The orbit graphs can be observed on the computer screen.

A comparison of Espocan and Tuohy needles for the combined spinal-epidural technique for labor analgesia.

PubMed

Browne, Ingrid M; Birnbach, David J; Stein, Deborah J; O'Gorman, David A; Kuroda, Maxine

2005-08-01

When using the needle-through-needle combined spinal-epidural (CSE) technique for labor analgesia, failure to obtain cerebrospinal fluid (CSF), paresthesias, and intrathecal or intravascular migration of the catheter are of concern. Epidural needles with spinal needle apertures, such as the back-hole Espocan (ES) needles, are available and may reduce these risks. We describe the efficacy and adverse events associated with a modified epidural needle (ES) versus a conventional Tuohy needle for CSE. One-hundred parturients requesting labor analgesia (CSE) were randomized into 2 groups: 50-ES 18-gauge modified epidural needle with 27-gauge Pencan atraumatic spinal needle, 50-conventional 18-gauge Tuohy needle with 27-gauge Gertie Marx atraumatic spinal needle. Information on intrathecal or intravascular catheter placement, paresthesia on introduction of spinal needle, failure to obtain CSF through the spinal needle after placement of epidural needle, unintentional dural puncture, and epidural catheter function was obtained. No intrathecal catheter placement occurred in either group. Rates of intravascular catheter placement and unintentional dural puncture were similar between the groups. Significant differences were noted regarding spinal needle-induced paresthesia (14% ES versus 42% Tuohy needles, P = 0.009) and failure to obtain CSF on first attempt (8% ES versus 28% Tuohy needles, P < 0.02). Use of ES needles for CSE significantly reduces paresthesia associated with the insertion of the spinal needle and is associated with more frequent successful spinal needle placement on the first attempt. The use of modified epidural needles with a back hole for combined spinal-epidural technique significantly reduces paresthesia associated with the insertion of the spinal needle and is associated with more frequent successful spinal needle placement on the first attempt.

Biocompatibility of hydroxyapatite coatings deposited by pulse electrodeposition technique on the Nitinol superelastic alloy.

PubMed

Marashi-Najafi, F; Khalil-Allafi, J; Etminanfar, M R

2017-07-01

The present study deals with pulse electrochemical deposition of HA on NiTi alloy and in vitro evaluation of coatings. At first step, a thermo-chemical surface modification process was applied to control the Ni release of the alloy. The electrochemical deposition of CaP coatings was examined at both dilute and concentrated solutions. The morphology and the composition of coatings were studied using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Plate like and needle like morphologies were formed for dilute and concentrated solution respectively and HA phase was formed by increasing the pulse current density for both electrolyte. The thickness of the samples was measured using cross sectioning technique. Fibroblast cell culture test on the coated samples revealed that the HA coating obtained by dilute solution shows the best biocompatibility. Also, MTT assay showed the highest cell density and cell proliferation after 5days for the HA coating of dilute solution. The contact angle of samples was measured and the coated samples showed a hydrophilic surface. Soaking the sample in SBF revealed that the crystallization rate of calcium-phosphate compounds is higher on the plate like HA coating as compared to the needle like morphology. The P release of the HA coated samples was measured in a physiological saline solution and the results show that the ions releasing in the plate like coating are less than the needle like coating. It seems that the stability of the plate like coating in biological environments is responsible for the better biocompatibility of the coating. Copyright © 2017 Elsevier B.V. All rights reserved.

The integration of single fiber reflectance (SFR) spectroscopy during endoscopic ultrasound-guided fine needle aspirations (EUS-FNA) in pancreatic masses: a feasibility study

NASA Astrophysics Data System (ADS)

Stegehuis, Paulien L.; Boogerd, Leonora S. F.; Inderson, Akin; Veenendaal, Roeland A.; Bonsing, Bert A.; Amelink, Arjen; Vahrmeijer, Alexander L.; Dijkstra, Jouke; Robinson, Dominic J.

2016-03-01

EUS-FNA can be used for pathological confirmation of a suspicious pancreatic mass. However, performance depends on an on-site cytologist and time between punction and final pathology results can be long. SFR spectroscopy is capable of extracting biologically relevant parameters (e.g. oxygenation and blood volume) in real-time from a very small tissue volume at difficult locations. In this study we determined feasibility of the integration of SFR spectroscopy during EUSFNA procedures in pancreatic masses. Patients with benign and malignant pancreatic masses who were scheduled for an EUS-FNA were included. The working guide wire inside the 19 gauge endoscopic biopsy needle was removed and the sterile single fiber (300 μm core and 700 μm outer diameter, wide-angle beam, NA 0.22) inserted through the needle. Spectroscopy measurements in the visiblenear infrared wavelength region (400-900 nm) and autofluorescence measurements (excitation at 405 nm) were taken three times, and subsequently cytology was obtained. Wavelength dependent optical properties were compared to cytology results. We took measurements in 13 patients with corresponding cytology results (including mucinous tumor, ductal adenocarcinoma, neuroendocrine tumor, and pancreatitis). In this paper we show the first analyzed results comparing normal pancreatic tissue with cancerous tissue in the same patient. We found a large difference in blood volume fraction, and blood oxygenation was higher in normal tissue. Integration of SFR spectroscopy is feasible in EUS-FNA procedures, the workflow hardly requires changes and it takes little time. The first results differentiating normal from tumor tissue are promising.

Fluoroscopy-Guided Sacroiliac Intraarticular Injection via the Middle Portion of the Joint.

PubMed

Kurosawa, Daisuke; Murakami, Eiichi; Aizawa, Toshimi

2017-09-01

Sacroiliac intraarticular injection is necessary to confirm sacroiliac joint (SIJ) pain and is usually performed via the caudal one-third portion of the joint. However, this is occasionally impossible for anatomical reasons, and the success rate is low in clinical settings. We describe a technique via the middle portion of the joint. Observational study. Enrolled were 69 consecutive patients (27 men and 42 women, with an average age of 53 years) in whom the middle portion of 100 joints was targeted. With the patient lying prone-oblique with the painful side down, a spinal needle was inserted into the middle portion of the joint. Subsequently, the fluoroscopy tube was angled at a caudal tilt of 25-30° to clearly detect the recess between the ilium and sacrum and the needle depth and direction. When the needle reached the posterior joint line, 2% lidocaine was injected after the contrast medium outlined the joint. The success rate of the injection method was 80% (80/100). Among 80 successful cases, four were previously unsuccessful when the conventional method was used. Intraarticular injection using the new technique was unsuccessful in 20 joints; in three of these cases, the conventional method proved successful, and no techniques were successful in the other 17 cases. The injection technique via the middle portion of the joint can overcome some of the difficulties of the conventional injection method and can improve the chances of successful intraarticular injection. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Design of a probe for two-dimensional small angle detection

NASA Astrophysics Data System (ADS)

He, Haixia; Wang, Xuanze; Zhong, Yuning; Yang, Liangen; Cao, Hongduan

2008-10-01

A novel two-dimensional small angle probe is introduced, which is based on principle of auto-collimation and utilizes quadrant Si-photoelectric detector (QPD) as detection device. AC modulation, AC magnification and absolute value demodulation are incorporated to restrain the DC excursion caused by background light and noise etc and to improve the sensitivity and stability of angle detection. To ensure that while the laser is shining, the current signal (converted into voltage signal) of QPD also is linear to the AC modulation voltage, this paper adopted AC modulation signal (5400Hz) with a DC offset. AC magnification circuit with reasonable parameters is designed to inhibit DC drift and the impact of industrial frequency noise and to ensure good amplification to signal frequency at the same time. A piezoelectric-driven micro-angle generator is designed to demarcate the angle. The calibration data are input to single chip, and the measurement of angles can be shown in SMC1602A.

Visible and infrared polarization ratio spectroreflectometer

NASA Technical Reports Server (NTRS)

Batten, C. E. (Inventor)

1980-01-01

The instrument assists in determining the refractive index and absorption index, at different spectral frequencies, of a solid sample by illuminating the sample at various angles in incidence and measuring the corresponding reflected intensities at various spectral frequencies and polarization angles. The ratio of the intensity of the reflected light for parallel polarized light to that for perpendicular polarized light at two different angles of incidence can be used to determine the optical constants of the sample. The invention involves an apparatus for facilitating the utilization of a wide variety of angles of incidence. The light source and polarizing element are positioned on an outer platform; the sample is positioned on an inner platform. The two platforms rotate about a common axis and cooperate in their rotation such that the sample is rotated one degree for every two degrees of rotation of the light source. This maintains the impingement of the reflected light upon the detector for any angle of incidence without moving or adjusting the detector which allows a continuous change in the angle of incidence.

Measurement of frequency response in short thermocouple wires

NASA Technical Reports Server (NTRS)

Forney, L. J.; Meeks, E. L.; Ma, J.; Fralick, G. C.

1993-01-01

Experimental measurements are made for the steady-state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire (type K) and a two material wire (type T) with unequal material properties across the junction. The data for the amplitude ratio and phase angle are correlated to within 10 percent with the theoretical predictions of Fralick and Forney (1991). This is accomplished by choosing a natural frequency omega(sub n) for the wire data to correlate the first order response at large gas temperature frequencies. It is found that a large bead size, however, will increase the amplitude ratio at low frequencies but decrease the natural frequency of the wire. The phase angle data are also distorted for imperfect junctions.

Measurement of frequency response in short thermocouple wires

NASA Technical Reports Server (NTRS)

Forney, L. J.; Meeks, E. L.; Ma, J.

1991-01-01

Experimental measurements are made for the steady-state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire (type K) and a two material wire (type T) with unequal material properties across the junction. The data for the amplitude ratio and phase angle are correlated to within 10 percent with the theoretical predictions of Fralick and Forney (1991). This is accomplished by choosing a natural frequency omega(sub n) for the wire data to correlate the first order response at large gas temperature frequencies. It is found that a large bead size, however, will increase the amplitude ratio at low frequencies but decreas the natural frequency of the wire. The phase angle data are also distorted for imperfect junctions.

Effects of dynamic aeroelasticity on handling qualities and pilot rating

NASA Technical Reports Server (NTRS)

Swaim, R. L.; Yen, W.-Y.

1978-01-01

Pilot performance parameters, such as pilot ratings, tracking errors, and pilot comments, were recorded and analyzed for a longitudinal pitch tracking task on a large, flexible aircraft. The tracking task was programmed on a fixed-base simulator with a CRT attitude director display of pitch angle command, pitch angle, and pitch angle error. Parametric variations in the undamped natural frequencies of the two lowest frequency symmetric elastic modes were made to induce varying degrees of rigid body and elastic mode interaction. The results indicate that such mode interaction can drastically affect the handling qualities and pilot ratings of the task.

Microwave energy harvesting based on metamaterial absorbers with multi-layered square split rings for wireless communications

NASA Astrophysics Data System (ADS)

Karaaslan, Muharrem; Bağmancı, Mehmet; Ünal, Emin; Akgol, Oguzhan; Sabah, Cumali

2017-06-01

We propose the design of a multiband absorber based on multi-layered square split ring (MSSR) structure. The multi-layered metamaterial structure is designed to be used in the frequency bands such as WIMAX, WLAN and satellite communication region. The absorption levels of the proposed structure are higher than 90% for all resonance frequencies. In addition, the incident angle and polarization dependence of the multi-layered metamaterial absorber and harvester is also investigated and it is observed that the structure has polarization angle independent frequency response with good absorption characteristics in the entire working frequency band. The energy harvesting ratios of the structure is investigated especially for the resonance frequencies at which the maximum absorption occurs. The energy harvesting potential of the proposed MSSRs is as good as those of the structures given in the literature. Therefore, the suggested design having good absorption, polarization and angle independent characteristics with a wide bandwidth is a potential candidate for future energy harvesting applications in commonly used wireless communication bands, namely WIMAX, WLAN and satellite communication bands.

Electroacupuncture most effectively elicits depressor and bradycardic responses at 1 Hz in humans.

PubMed

Nakahara, Hidehiro; Kawada, Toru; Ueda, Shin-ya; Kawai, Eriko; Yamamoto, Hiromi; Sugimachi, Masaru; Miyamoto, Tadayoshi

2016-02-01

Acupuncture stimulation is known to act on the autonomic nervous system and elicits depressor and bradycardic effects. However, previous studies on humans did not conduct quantitative analyses on optimal acupuncture conditions such as the stimulation frequency and duration to achieve maximum depressor and bradycardic effects. The aim of the present study was to investigate the effects of varying stimulation frequencies of electroacupuncture on time-dependent changes in blood pressure and heart rate in humans. Twelve healthy volunteers participated in the study. An acupuncture needle was inserted at the Ximen acupoint (PC4 according to WHO nomenclature), located at the anterior aspect of the forearm. An electrical stimulation was delivered through the acupuncture needle at an intensity of 1 V, pulse width of 5 ms, and stimulation frequencies of 0.5, 1, 5, and 10 Hz in a random order. The duration of electroacupuncture was 6 min, during which blood pressure and heart rate responses were monitored. Group-averaged data indicated that 1-Hz electroacupuncture decreased blood pressure and heart rate. Blood pressure was significantly decreased from the prestimulation baseline value of 86.6 ± 2.9 to 81.4 ± 2.3 mmHg during 4-6 min of 1-Hz electroacupuncture (mean ± SE, P < 0.01). Heart rate was also significantly decreased (from 66.2 ± 2.0 to 62.7 ± 1.7 beats/min, P < 0.01). These results provide fundamental evidence that bradycardiac and depressor responses are effectively produced by electrical acupuncture in humans.

Different experimental results for the influence of immersion angle on the resonant frequency of a quartz crystal microbalance in a liquid phase: with a comment.

PubMed

Shen, Dazhong; Kang, Qi; Li, Xiaoyu; Cai, Hongmei; Wang, Yuandong

2007-06-19

This paper presents different experimental results of the influence of an immersion angle (theta, the angle between the surface of a quartz crystal resonator and the horizon) on the resonant frequency of a quartz crystal microbalance (QCM) sensor exposed one side of its sensing surfaces to liquid. The experimental results show that the immersion angle is an added factor that may influence the frequency of the QCM sensor. This type of influence is caused by variation of the reflection conditions of the longitudinal wave between the QCM sensor and the walls of the detection cell. The frequency shifts, measured by varying theta, are related to the QCM sensor used. When a QCM sensor with a weak longitudinal wave is used, its resonant frequency is nearly independent of theta. But, if a QCM sensor with a strong longitudinal wave is employed, the immersion angle is a potential error source for the measurements performed on the QCM sensor. When the reflection conditions of the longitudinal wave are reduced, the influence of theta on the resonant frequency of the QCM sensor is negligible. The slope of the plot of frequency shifts (deltaF) versus (rho eta)(1/2), the square root of the product of solution density (rho) and viscosity (eta), may be influenced by theta in a single experiment for the QCM sensor with a strong longitudinal wave in low viscous liquids, which can however, be effectively weakened by using the averaged values of reduplicated experiments. In solutions with a large (rho eta)(1/2) region (0-55 wt% sucrose solution as an example, with rho value from 1.00 to 1.26 g cm(-3) and eta value from 0.01 to 0.22 g cm(-1) s(-1), respectively), the slope of the plot of deltaF versus (rho eta)(1/2) is independent of theta even for the QCM sensor with a strong longitudinal wave in a single experiment. The influence of theta on the resonant frequency of the QCM sensor should be taken into consideration in its applications in liquid phase.

Optimizing EUS-guided liver biopsy sampling: comprehensive assessment of needle types and tissue acquisition techniques.

PubMed

Schulman, Allison R; Thompson, Christopher C; Odze, Robert; Chan, Walter W; Ryou, Marvin

2017-02-01

EUS-guided liver biopsy sampling using FNA and, more recently, fine-needle biopsy (FNB) needles has been reported with discrepant diagnostic accuracy, in part due to differences in methodology. We aimed to compare liver histologic yields of 4 EUS-based needles and 2 percutaneous needles to identify optimal number of needle passes and suction. Six needle types were tested on human cadaveric tissue: one 19G FNA needle, one existing 19G FNB needle, one novel 19G FNB needle, one 22G FNB needle, and two 18G percutaneous needles (18G1 and 18G2). Two needle excursion patterns (1 vs 3 fanning passes) were performed on all EUS needles. Primary outcome was number of portal tracts. Secondary outcomes were degree of fragmentation and specimen adequacy. Pairwise comparisons were performed using t tests, with a 2-sided P < .05 considered to be significant. Multivariable regression analysis was performed. In total, 288 liver biopsy samplings (48 per needle type) were performed. The novel 19G FNB needle had significantly increased mean portal tracts compared with all needle types. The 22G FNB needle had significantly increased portal tracts compared with the 18G1 needle (3.8 vs 2.5, P < .001) and was not statistically different from the 18G2 needle (3.8 vs 3.5, P = .68). FNB needles (P < .001) and 3 fanning passes (P ≤ .001) were independent predictors of the number of portal tracts. A novel 19G EUS-guided liver biopsy needle provides superior histologic yield compared with 18G percutaneous needles and existing 19G FNA and core needles. Moreover, the 22G FNB needle may be adequate for liver biopsy sampling. Investigations are underway to determine whether these results can be replicated in a clinical setting. Copyright © 2017 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Subsonic roll oscillation experiments on the Standard Dynamics Model

NASA Technical Reports Server (NTRS)

Beyers, M. E.

1983-01-01

The experimental determination of the subsonic roll derivatives of the Standard Dynamics Model, which is representative of a current fighter aircraft configuration, is described. The direct, cross and cross-coupling derivatives are presented for angles of attack up to 41 deg and sideslip angles in the range from -5 deg to 5 deg, as functions of oscillation frequency. The derivatives exhibited significant nonlinear trends at high incidences and were found to be extremely sensitive to sideslip angle at angles of attack near 36 deg. The roll damping and dynamic cross derivatives were highly frequency dependent at angles of attack above 30 deg. The highest values measured for the dynamic cross and cross-coupling derivatives were comparable in magnitude with the maximum roll damping. The effects of oscillation amplitude and Mach number were also investigated, and the direct derivatives were correlated with data from another facility.

Relationship between directions of wave and energy propagation for cold plasma waves

NASA Technical Reports Server (NTRS)

Musielak, Zdzislaw E.

1986-01-01

The dispersion relation for plasma waves is considered in the 'cold' plasma approximation. General formulas for the dependence of the phase and group velocities on the direction of wave propagation with respect to the local magnetic field are obtained for a cold magnetized plasma. The principal cold plasma resonances and cut-off frequencies are defined for an arbitrary angle and are used to establish basic regimes of frequency where the cold plasma waves can propagate or can be evanescent. The relationship between direction of wave and energy propagation, for cold plasma waves in hydrogen atmosphere, is presented in the form of angle diagrams (angle between group velocity and magnetic field versus angle between phase velocity and magnetic field) and polar diagrams (also referred to as 'Friedrich's diagrams') for different directions of wave propagation. Morphological features of the diagrams as well as some critical angles of propagation are discussed.

Aneurysm clip motion during magnetic resonance imaging: in vivo experimental study with metallurgical factor analysis.

PubMed

Dujovny, M; Kossovsky, N; Kossowsky, R; Valdivia, R; Suk, J S; Diaz, F G; Berman, S K; Cleary, W

1985-10-01

Because of various mechanical, metallurgical, and commercial constraints, aneurysm clips are manufactured from different alloys, including several stainless steel and cobalt alloys. Some of the steels contain volume fractions of the crystal phase known as martensite. Martensitic alloys have body-centered cubic structure, are prone to stress corrosion failure, and are ferromagnetic. Martensitic steel can be displaced like a compass needle when exposed to a magnetic field such as that generated during magnetic resonance imaging (MRI). The force exerted by the magnetic field is proportional to the volume fraction of the magnetic phase. We investigated the martensitic content and magnetic field-induced displacement of 12 common aneurysm clips. Four clips of each of the following types were examined: Sugita, Sundt-Kees Multi-Angle, Heifetz (two types), Vari-Angle McFadden, Yasargil (two types), Scoville, Mayfield, Vari-Angle, Pivot, and Kapp. Phase homogeneity and crystal structure were analyzed by x-ray diffraction using a Phillips x-ray diffractometer. Clip deflection in an Oxford Research Systems MRI spectrometer was measured in our in vivo rat abdominal aortic aneurysm model. Results showed that the volume fraction of the martensitic phase in the various clips correlated with the magnitude of the deflection. Among the clips examined, the Yasargil, Sugita, Heifetz Elgiloy, and Vari-Angle McFadden had a nonmartensitic composition and did not deflect in the magnetic field. The Scoville contained 5% martensite and deflected only marginally. Martensite comprised 35% of the Mayfield clip, which deflected 45 degrees, and 90% of the Heifetz, Vari-Angle, Pivot, and Sundt-Kees Multi-Angle clips, which deflected approximately 70 degrees or slipped off the aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Monitoring radio-frequency thermal ablation with ultrasound by low frequency acoustic emissions--in vitro and in vivo study.

PubMed

Winkler, Itai; Adam, Dan

2011-05-01

The object of this study was to evaluate the monitoring of thermal ablation therapy by measuring the nonlinear response to ultrasound insonation at the region being treated. Previous reports have shown that during tissue heating, microbubbles are formed. Under the application of ultrasound, these microbubbles may be driven into nonlinear motion that produces acoustic emissions at sub-harmonic frequencies and a general increase of emissions at low frequencies. These low frequency emissions may be used to monitor ablation surgery. In this study, a modified commercial ultrasound system was used for transmitting ultrasound pulses and for recording raw RF-lines from a scan plane in porcine (in vitro) and rabbit (in vivo) livers during radio-frequency ablation (RFA). The transmission pulse was 15 cycles in length at 4 MHz (in vitro) and 3.6 MHz (in vivo). Thermocouples were used for monitoring temperatures during the RFA treatment.In the in vitro experiments, recorded RF signals (A-lines) were segmented, and the total energy was measured at two different frequency bands: at a low frequency band (LFB) of 1-2.5 MHz and at the transmission frequency band (TFB) of 3.5-4.5 MHz. The mean energy at the LFB and at the TFB increased substantially in areas adjacent to the RF needle. These energies also changed abruptly at higher temperatures, thus, producing great variance in the received energy. Mean energies in areas distant from RF needle showed little change and variation during treatment. It was also shown that a 3 dB increase of energy at the low frequency band was typically obtained in regions in which temperature was above 53.3 ± 5° C. Thus, this may help in evaluating regions undergoing hyperthermia. In the in vivo experiments, an imaging algorithm based on measuring the LFB energy was used. The algorithm performs a moving average of the LFB energies measured at segments within the scan plane.Results show that a colored region is formed on the image and that it is similar in size to a measurement of the lesion from gross pathology, with a correlation coefficient of 0.743. Copyright © 2011. Published by Elsevier Inc.

Apex-angle-dependent resonances in triangular split-ring resonators

NASA Astrophysics Data System (ADS)

Burnett, Max A.; Fiddy, Michael A.

2016-02-01

Along with other frequency selective structures (Pendry et al. in IEEE Trans Microw Theory Tech 47(11):2075-2084, 1999) (circles and squares), triangular split-ring resonators (TSRRs) only allow frequencies near the center resonant frequency to propagate. Further, TSRRs are attractive due to their small surface area (Vidhyalakshmi et al. in Stopband characteristics of complementary triangular split ring resonator loaded microstrip line, 2011), comparatively, and large quality factors ( Q) as previously investigated by Gay-Balmaz et al. (J Appl Phys 92(5):2929-2936, 2002). In this work, we examine the effects of varying the apex angle on the resonant frequency, the Q factor, and the phase shift imparted by the TSRR element within the GHz frequency regime.

Transperineal prostate biopsy under magnetic resonance image guidance: a needle placement accuracy study.

PubMed

Blumenfeld, Philip; Hata, Nobuhiko; DiMaio, Simon; Zou, Kelly; Haker, Steven; Fichtinger, Gabor; Tempany, Clare M C

2007-09-01

To quantify needle placement accuracy of magnetic resonance image (MRI)-guided core needle biopsy of the prostate. A total of 10 biopsies were performed with 18-gauge (G) core biopsy needle via a percutaneous transperineal approach. Needle placement error was assessed by comparing the coordinates of preplanned targets with the needle tip measured from the intraprocedural coherent gradient echo images. The source of these errors was subsequently investigated by measuring displacement caused by needle deflection and needle susceptibility artifact shift in controlled phantom studies. Needle placement error due to misalignment of the needle template guide was also evaluated. The mean and standard deviation (SD) of errors in targeted biopsies was 6.5 +/- 3.5 mm. Phantom experiments showed significant placement error due to needle deflection with a needle with an asymmetrically beveled tip (3.2-8.7 mm depending on tissue type) but significantly smaller error with a symmetrical bevel (0.6-1.1 mm). Needle susceptibility artifacts observed a shift of 1.6 +/- 0.4 mm from the true needle axis. Misalignment of the needle template guide contributed an error of 1.5 +/- 0.3 mm. Needle placement error was clinically significant in MRI-guided biopsy for diagnosis of prostate cancer. Needle placement error due to needle deflection was the most significant cause of error, especially for needles with an asymmetrical bevel. (c) 2007 Wiley-Liss, Inc.

Efficacy and safety of manual acupuncture manipulations with different frequencies on epigastric pain syndrome (EPS) in functional dyspepsia (FD) patients: study protocol for a randomized controlled trial.

PubMed

Hong, Shou-Hai; Ding, Sha-Sha; Wu, Fei; Bi, Ying; Xu, Fu; Wan, Yi-Jia; Xuan, Li-Hua

2017-03-06

Manual acupuncture (MA) manipulations are one of the key factors influencing acupuncture effects in traditional Chinese medicine theory. Different MA manipulations contain different stimulating parameters, thus generating different acupuncture responses or effects. Evidence has demonstrated that acupuncture is effective for functional dyspepsia (FD). However, the effects of different stimulating parameters of MA manipulations on FD remain unclear. This study is a randomized controlled trial with a four-arm, parallel-group structure. Patients with FD with epigastric pain syndrome (EPS) will be included and randomly allocated into four groups: three MA manipulation groups (separately treated with a frequency of 1 Hz, 2 Hz, or 3 Hz) and a control group. All groups will receive omeprazole as a basic treatment and acupuncture: in the MA manipulation groups, the needles will be manipulated manually with three different frequencies on the basis when de qi is reached, while in the control group, the needles will be inserted without any manipulation. All patients will receive acupuncture treatment of five consecutive sessions per week for 2 weeks and be followed up at 4, 8, and 12 weeks. The primary outcomes of the study include patients' response to the treatment. The secondary outcomes include dyspeptic symptoms, quality of life, mental status, fasting serum gastrin, motilin, and ghrelin concentrations, and adverse events. The protocol was approved by the Ethics committee of the First Affiliated Hospital of Zhejiang Chinese Medical University (2016-K-057-01). The aim of this study is to evaluate the efficacy and safety of MA manipulations with different stimulating parameters (different frequencies) on EPS in patients with FD. Chinese Clinical Trial Registry, ChiCTR-IOR-16008189 . Registered on 30 March 2016.

The effect of grain boundary misorientation on the intergranular M 23C 6 carbide precipitation in thermally treated Alloy 690

NASA Astrophysics Data System (ADS)

Lim, Yun Soo; Kim, Joung Soo; Kim, Hong Pyo; Cho, Hai Dong

2004-10-01

The precipitation characteristics of chromium carbides on various types of grain boundaries in Alloy 690 thermally treated at 720 °C for 10 h were studied through transmission electron microscopy. Precipitation of the intergranular chromium carbides, identified as Cr-rich M 23C 6, was retarded on the low angle grain boundaries, compared to that on the random high angle grain boundaries on which coarse and discrete ones were found. They were rarely found on the coherent twin boundaries, however, needle-like ones were evolved on the incoherent twin and twin related Σ9 boundaries. Precipitation of the chromium carbides was also suppressed on the nearly exact coincidence site lattice boundaries such as Σ11 and Σ15, for which the Brandon criterion was fulfilled. The results of the intergranular M 23C 6 carbide precipitation were explained in terms of the influence of the grain boundary energy.

Parotid Abscess with Involvement of Facial Nerve Branches.

PubMed

Ozkan, Adile; Ors, Ceyda Hayretdag; Kosar, Sule; Ozisik Karaman, Handan Isin

2015-08-01

Facial nerve paresis is only rarely seen with benign diseases of the parotid gland. A 22-year male had muscle loss in the preauricular region of the right side of his face that extended towards the mandibular angle for the last 6 months. The neurological examination did not reveal any pathology other than right preauricular region muscle atrophy that was limited by the mandibular angle. The Electroneuronography (EnoG) provided a ratio of 55.38%, compared the affected side to left side. Ultrasonography of the defined region showed two mass lesions 13.5 x 7 mm and 10 x 5 mm in size in the anteromedial section of the right parotid gland that were close to each other, without internal calcific foci, and heterogenous hyperechogenic structure without internal vascularization. Fine needle aspiration obtained many polymorphonuclear leukocytes, cell debris, a few mononuclear inflammatory cells and many crystalloid structures. The lesion was diagnosed as a parotid abscess. Antibiotic treatment was started for the parotid gland abscess.

Safety and efficacy of pancreatic sphincterotomy in chronic pancreatitis.

PubMed

Ell, C; Rabenstein, T; Schneider, H T; Ruppert, T; Nicklas, M; Bulling, D

1998-09-01

Endoscopic pancreatic sphincterotomy (EPS) is being performed with increasing frequency as a prerequisite to interventional measures in the pancreatic duct. The aim of this study was to evaluate EPS with regard to technique, success, complications, and mortality in patients with chronic pancreatitis. Between January 1989 and September 1996, the results of all consecutive EPSs in patients with chronic pancreatitis were documented in a standardized form. Patients were followed by clinical investigation and blood sample analysis at 4, 24, and 48 hours after EPS. Complications were classified according to commonly accepted criteria. EPS was performed in 118 patients with chronic pancreatitis (men 75%, women 25%, 48+/-10 years). Ninety-four patients (80%) underwent guidewire-assisted EPS, and 24 patients (20%) underwent needle-knife EPS. Seventy-seven EPS procedures (65%) were primarily successful (guidewire EPS: 60 of 94, 64%; needle-knife EPS: 17 of 24, 71%). Additional endoscopic cutting techniques (needle-knife papillotomy, biliary endoscopic sphincterotomy) were required in 41 patients (35%). In total, EPS was successful in 116 patients (98%). The complication rate was 4.2% (4 cases of moderate pancreatitis, 1 severe bleeding, no deaths). All complications were managed nonoperatively. In patients with chronic pancreatitis, EPS with a standard sphincterotome or with a needle-knife offers an effective and reliable approach to the pancreatic duct system. Additional cutting techniques may be necessary in approximately one third of cases before an EPS can be successfully performed. The complication rate of EPS in patients with chronic pancreatitis appears to be lower than the complication rate of biliary sphincterotomy for other indications.

Impacts of seasonal air and soil temperatures on photosynthesis in Scots pine trees.

PubMed

Strand, Martin; Lundmark, Tomas; Söderbergh, Ingrid; Mellander, Per-Erik

2002-08-01

Seasonal courses of light-saturated rate of net photosynthesis (A360) and stomatal conductance (gs) were examined in detached 1-year-old needles of Scots pine (Pinus sylvestris L.) from early April to mid-November. To evaluate the effects of soil frost and low soil temperatures on gas exchange, the extent and duration of soil frost, as well as the onset of soil warming, were manipulated in the field. During spring, early summer and autumn, the patterns of A360 and gs in needles from the control and warm-soil plots were generally strongly related to daily mean air temperatures and the frequency of severe frost. The warm-soil treatment had little effect on gas exchange, although mean soil temperature in the warm-soil plot was 3.8 degrees C higher than in the control plot during spring and summer, indicating that A360 and gs in needles from control trees were not limited by low soil temperature alone. In contrast, prolonged exposure to soil temperatures slightly above 0 degrees C severely restricted recovery of A360 and especially gs in needles from the cold-soil treatment during spring and early summer; however, full recovery of both A360 and gs occurred in late summer. We conclude that inhibition of A360 by low soil temperatures is related to both stomatal closure and effects on the biochemistry of photosynthesis, the relative importance of which appeared to vary during spring and early summer. During the autumn, soil temperatures as low as 8 degrees C did not affect either A360 or gs.

Small-Molecule Type III Secretion System Inhibitors Block Assembly of the Shigella Type III Secreton▿ †

PubMed Central

Veenendaal, Andreas K. J.; Sundin, Charlotta; Blocker, Ariel J.

2009-01-01

Type III secretion systems (T3SSs) are essential virulence devices for many gram-negative bacteria that are pathogenic for plants, animals, and humans. They serve to translocate virulence effector proteins directly into eukaryotic host cells. T3SSs are composed of a large cytoplasmic bulb and a transmembrane region into which a needle is embedded, protruding above the bacterial surface. The emerging antibiotic resistance of bacterial pathogens urges the development of novel strategies to fight bacterial infections. Therapeutics that rather than kill bacteria only attenuate their virulence may reduce the frequency or progress of resistance emergence. Recently, a group of salicylidene acylhydrazides were identified as inhibitors of T3SSs in Yersinia, Chlamydia, and Salmonella species. Here we show that these are also effective on the T3SS of Shigella flexneri, where they block all related forms of protein secretion so far known, as well as the epithelial cell invasion and induction of macrophage apoptosis usually demonstrated by this bacterium. Furthermore, we show the first evidence for the detrimental effect of these compounds on T3SS needle assembly, as demonstrated by increased numbers of T3S apparatuses without needles or with shorter needles. Therefore, the compounds generate a phenocopy of T3SS export apparatus mutants but with incomplete penetrance. We discuss why this would be sufficient to almost completely block the later secretion of effector proteins and how this begins to narrow the search for the molecular target of these compounds. PMID:18996990

Broad fibrovascular cores may not be an exclusively benign feature in papillary lesions of the breast: a cautionary note.

PubMed

Yamaguchi, Rin; Tanaka, Maki; Tse, Gary M; Yamaguchi, Miki; Terasaki, Hiroshi; Nomura, Yoriko; Takenaka, Miki; Naito, Yoshiki; Akiba, Jun; Yano, Hirohisa

2014-03-01

A prominent fibrovascular stromal core is one of the widely accepted histological features of breast papillomas, but some papillary carcinomas also show such broad fibrovascular cores, leading to confusion in diagnosis, particularly in needle biopsy specimens. We investigated the histological characteristics of papillary lesions, focusing on broad fibrovascular cores and their relationship with the architectural patterns. Among 185 cases of needle biopsies of papillomas and papillary carcinomas, the number of cases with broad fibrovascular cores in each group was compared. The broad fibrovascular core density in the subsequently resected specimens was evaluated and compared between papillary predominant pattern (papillary structures >80% of tumours) and mixed pattern (papillary, solid, cribriform and others) within the lesions. Significantly more papillary carcinomas than papillomas and B3 atypical papillary lesions had broad fibrovascular cores (p=0.0091 and p=0.0164, respectively). The papillary predominant pattern was more prominent in carcinomas than in papillomas in the needle biopsies (p=0.048) and showed the same tendency in the resections (p=0.058). The broad fibrovascular core density was significantly lower in the 18 papillomas than in the 37 papillary carcinomas (p=0.0079) and was not significantly different between the papillary predominant and mixed patterns in carcinomas and papillomas. Broad fibrovascular cores in mammary papillary lesions are not specific for papillomas, as they are also present focally in papillary carcinomas. As the frequency of papillary carcinoma with broad fibrovascular cores is relatively high, caution in diagnosis has to be exercised, especially in needle biopsy specimens.

Occupational exposure to HIV: a conflict situation for health workers.

PubMed

Kumakech, E; Achora, S; Berggren, V; Bajunirwe, F

2011-12-01

To determine the frequency of occupational exposure to human immunodeficiency virus (HIV), the circumstances and predisposing factors, the high-risk groups, the extent to which exposures are reported and the post-exposure prophylaxis (PEP) utilized by health-care workers (HCWs) and students in a Ugandan hospital. Occupational exposure to HIV is a low but potential risk of HIV infection to health workers. Self-administered questionnaire was given to 224 participants (including 98 HCWs and 126 students) in Mbarara Hospital, Uganda. Data were analysed with descriptive statistics using the Statistical Package for the Social Sciences version 15.0 (SPSS Inc, Chicago, IL, USA). Of the 224 participants surveyed, 19.2% reported having sustained injection needle stick injuries in the previous year, of which 4.46% occurred with HIV-infected blood. Other reported injuries were cannula needle stick injury (0.89%), suture needle stick injuries (3.13%), scalpel cut injuries (0.45%) and muco-cutaneous contamination (10.27%). The most affected groups were nurses-midwives for scalpel injuries and students for stick injuries. The predisposing factors reported included lack of protective devices and recapping of needles. Exposures were under-reported. Uptake of PEP was also low. Occupational exposure to HIV presents a conflict situation for HCWs. It remains a frequent occurrence particularly among student nurses-midwives, despite being avoidable. Its prophylactic treatment is hampered by poor reporting and investigation of exposures, and poor access to PEP. Strict adherence to universal precaution and proper handling of occupational exposure to HIV should be encouraged. © 2011 The Authors. International Nursing Review © 2011 International Council of Nurses.

An angle-by-angle approach to predicting broadband high-frequency sound fields in rectangular enclosures with experimental comparison.

PubMed

Franzoni, Linda P; Elliott, Christopher M

2003-10-01

Experiments were performed on an elongated rectangular acoustic enclosure with different levels of absorptive material placed on side walls and an end wall. The acoustic source was a broadband high-frequency sound from a loudspeaker flush-mounted to an end wall of the enclosure. Measurements of sound-pressure levels were averaged in cross sections of the enclosure and then compared to theoretical results. Discrepancies between the experimental results and theoretical predictions that treated all incidence angles as equally probable led to the development of an angle-by-angle approach. The new approach agrees well with the experimentally obtained values. In addition, treating the absorptive material as bulk reacting rather than point reacting was found to significantly change the theoretical value for the absorption coefficient and to improve agreement with experiment. The new theory refines an earlier theory based on power conservation and locally diffuse assumptions. Furthermore, the new theory includes both the angle of incidence effects on the resistive and reactive properties of the absorptive material, and the effects of angle filtering, i.e., that reflecting waves associated with shallow angles become relatively stronger than those associated with steep angles as a function of distance from the source.

Broadband and wide-angle RCS reduction using a 2-bit coding ultrathin metasurface at terahertz frequencies

PubMed Central

Liang, Lanju; Wei, Minggui; Yan, Xin; Wei, Dequan; Liang, Dachuan; Han, Jiaguang; Ding, Xin; Zhang, GaoYa; Yao, Jianquan

2016-01-01

A novel broadband and wide-angle 2-bit coding metasurface for radar cross section (RCS) reduction is proposed and characterized at terahertz (THz) frequencies. The ultrathin metasurface is composed of four digital elements based on a metallic double cross line structure. The reflection phase difference of neighboring elements is approximately 90° over a broadband THz frequency. The mechanism of RCS reduction is achieved by optimizing the coding element sequences, which redirects the electromagnetic energies to all directions in broad frequencies. An RCS reduction of less than −10 dB bandwidth from 0.7 THz to 1.3 THz is achieved in the experimental and numerical simulations. The simulation results also show that broadband RCS reduction can be achieved at an incident angle below 60° for TE and TM polarizations under flat and curve coding metasurfaces. These results open a new approach to flexibly control THz waves and may offer widespread applications for novel THz devices. PMID:27982089

Numerical analysis of deposition frequency for successive droplets coalescence dynamics

NASA Astrophysics Data System (ADS)

Cheng, Xiaoding; Zhu, Yunlong; Zhang, Lei; Zhang, Dingyi; Ku, Tao

2018-04-01

A pseudopotential based multi-relaxation-time lattice Boltzmann model is employed to investigate the dynamic behaviors of successive droplets' impact and coalescence on a solid surface. The effects of deposition frequency on the morphology of the formed line are investigated with a zero receding contact angle by analyzing the droplet-to-droplet coalescence dynamics. Two collision modes (in-phase mode and out-of-phase mode) between the pre-deposited bead and the subsequent droplet are identified depending on the deposition frequency. A uniform line can be obtained at the optimal droplet spacing in the in-phase mode (Δt* < 1.875). However, a scalloped line pattern is formed in the out-of-phase mode (Δt* > 1.875). It is found that decreasing the droplet spacing or advancing contact angle can improve the smoothness of line in the out-of-phase mode. Furthermore, the effects of deposition frequency on the morphology of the formed lines are validated to be applicable to cases with a finite receding contact angle.

Radar response to vegetation. [soil moisture mapping via microwave backscattering

NASA Technical Reports Server (NTRS)

Ulaby, F. T.

1975-01-01

Active microwave measurements of vegetation backscatter were conducted to determine the utility of radar in mapping soil moisture through vegetation and mapping crop types. Using a truck-mounted boom, spectral response data were obtained for four crop types (corn, milo, soybeans, and alfalfa) over the 4-8 GHz frequency band, at incidence angles of 0 to 70 degrees in 10-degree steps, and for all four linear polarization combinations. Based on a total of 125 data sets covering a wide range of soil moisture, content, system design criteria are proposed for each of the aforementioned objectives. Quantitative soil moisture determination was best achieved at the lower frequency end of the 4-8 GHz band using HH polarized waves in the 5- to 15-degree incidence angle range. A combination of low and high frequency measurements are suggested for classifying crop types. For crop discrimination, a dual-frequency dual-polarization (VV and cross) system operating at incidence angles above 40 degrees is suggested.

Broadband and wide-angle RCS reduction using a 2-bit coding ultrathin metasurface at terahertz frequencies.

PubMed

Liang, Lanju; Wei, Minggui; Yan, Xin; Wei, Dequan; Liang, Dachuan; Han, Jiaguang; Ding, Xin; Zhang, GaoYa; Yao, Jianquan

2016-12-16

A novel broadband and wide-angle 2-bit coding metasurface for radar cross section (RCS) reduction is proposed and characterized at terahertz (THz) frequencies. The ultrathin metasurface is composed of four digital elements based on a metallic double cross line structure. The reflection phase difference of neighboring elements is approximately 90° over a broadband THz frequency. The mechanism of RCS reduction is achieved by optimizing the coding element sequences, which redirects the electromagnetic energies to all directions in broad frequencies. An RCS reduction of less than -10 dB bandwidth from 0.7 THz to 1.3 THz is achieved in the experimental and numerical simulations. The simulation results also show that broadband RCS reduction can be achieved at an incident angle below 60° for TE and TM polarizations under flat and curve coding metasurfaces. These results open a new approach to flexibly control THz waves and may offer widespread applications for novel THz devices.

High frequency estimation of 2-dimensional cavity scattering

NASA Astrophysics Data System (ADS)

Dering, R. S.

1984-12-01

This thesis develops a simple ray tracing approximation for the high frequency scattering from a two-dimensional cavity. Whereas many other cavity scattering algorithms are very time consuming, this method is very swift. The analytical development of the ray tracing approach is performed in great detail, and it is shown how the radar cross section (RCS) depends on the cavity's length and width along with the radar wave's angle of incidence. This explains why the cavity's RCS oscillates as a function of incident angle. The RCS of a two dimensional cavity was measured experimentally, and these results were compared to computer calculations based on the high frequency ray tracing theory. The comparison was favorable in the sense that angular RCS minima and maxima were exactly predicted even though accuracy of the RCS magnitude decreased for incident angles far off-axis. Overall, once this method is extended to three dimensions, the technique shows promise as a fast first approximation of high frequency cavity scattering.

Echocardiography-guided or "sided" pericardiocentesis.

PubMed

Degirmencioglu, Aleks; Karakus, Gultekin; Güvenc, Tolga Sinan; Pinhan, Osman; Sipahi, Ilke; Akyol, Ahmet

2013-10-01

Echocardiography-guided pericardiocentesis is the first choice method for relieving cardiac tamponade, but the exact role of the echocardiography at the moment of the puncture is still controversial. In this report, detailed echocardiographic evaluation was performed in 21 consecutive patients with cardiac tamponade just before the pericardiocentesis. Appropriate needle position was determined according to the probe position using imaginary x, y, and z axes. Pericardiocentesis was performed successfully using this technique without simultaneous echocardiography and no complications were observed. We concluded that bedside echocardiography with detailed evaluation of the puncture site and angle is enough for pericardiocentesis instead of real time guiding. © 2013, Wiley Periodicals, Inc.

Stereo Navi 2.0: software for stereotaxic surgery of the common marmoset (Callithrix jacchus).

PubMed

Tokuno, Hironobu; Tanaka, Ikuko; Umitsu, Yoshitomo; Nakamura, Yasuhisa

2009-11-01

Recently, we reported our web-accessible digital brain atlas of the common marmoset (Callithrix jacchus) at http://marmoset-brain.org:2008. Using digital images obtained during construction of this website, we developed stand-alone software for navigation of electrodes or injection needles for stereotaxic electrophysiological or anatomical experiments in vivo. This software enables us to draw lines on exchangeable section images, measure the length and angle of lines, superimpose a stereotaxic reference grid on the image, and send the image to the system clipboard. The software, Stereo Navi 2.0, is freely available at our brain atlas website.

Tunable all-angle negative refraction and photonic band gaps in two-dimensional plasma photonic crystals with square-like Archimedean lattices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Hai-Feng, E-mail: hanlor@163.com, E-mail: lsb@nuaa.edu.cn; Nanjing Artillery Academy, Nanjing 211132; Liu, Shao-Bin, E-mail: hanlor@163.com, E-mail: lsb@nuaa.edu.cn

In this paper, the tunable all-angle negative refraction and photonic band gaps (PBGs) in two types of two-dimensional (2D) plasma photonic crystals (PPCs) composed of homogeneous plasma and dielectric (GaAs) with square-like Archimedean lattices (ladybug and bathroom lattices) for TM wave are theoretically investigated based on a modified plane wave expansion method. The type-1 structure is dielectric rods immersed in the plasma background, and the complementary structure is named as type-2 PPCs. Theoretical simulations demonstrate that the both types of PPCs with square-like Archimedean lattices have some advantages in obtaining the higher cut-off frequency, the larger PBGs, more number ofmore » PBGs, and the relative bandwidths compared to the conventional square lattices as the filling factor or radius of inserted rods is same. The influences of plasma frequency and radius of inserted rod on the properties of PBGs for both types of PPCs also are discussed in detail. The calculated results show that PBGs can be manipulated by the parameters as mentioned above. The possibilities of all-angle negative refraction in such two types of PPCs at low bands also are discussed. Our calculations reveal that the all-angle negative phenomena can be observed in the first two TM bands, and the frequency range of all-angle negative refraction can be tuned by changing plasma frequency. Those properties can be used to design the optical switching and sensor.« less

Structure formation in grade 20 steel during equal-channel angular pressing and subsequent heating

NASA Astrophysics Data System (ADS)

Dobatkin, S. V.; Odesskii, P. D.; Raab, G. I.; Tyutin, M. R.; Rybalchenko, O. V.

2016-11-01

The structure formation and the mechanical properties of quenched and tempered grade 20 steel after equal-channel angular pressing (ECAP) at various true strains and 400°C are studied. Electron microscopy analysis after ECAP shows a partially submicrocrystalline and partially subgrain structure with a structural element size of 340-375 nm. The structural element size depends on the region in which the elements are formed (polyhedral ferrite, needle-shaped ferrite, tempered martensite, and pearlite). Heating of the steel after ECAP at 400 and 450°C increases the fraction of high-angle boundaries and the structural ferrite element size to 360-450 nm. The fragmentation and spheroidization of cementite lamellae of pearlite and subgrain coalescence in the regions of needle-shaped ferrite and tempered martensite take place at a high ECAP true strain and heating temperature. Structural refinement ensures considerable strengthening, namely, UTS 742-871 MPa at EL 11-15.3%. The strength slightly increases, whereas the plasticity slightly decreases when the true strain increases during ECAP. After ECAP and heating, the strength and plastic properties of the grade 20 steel remain almost the same.

Fiber Bragg grating based arterial localization device

NASA Astrophysics Data System (ADS)

Ho, Siu Chun Michael; Li, Weijie; Razavi, Mehdi; Song, Gangbing

2017-06-01

A critical first step to many surgical procedures is locating and gaining access to a patients vascular system. Vascular access allows the deployment of other surgical instruments and also the monitoring of many physiological parameters. Current methods to locate blood vessels are predominantly based on the landmark technique coupled with ultrasound, fluoroscopy, or Doppler. However, even with experience and technological assistance, locating the required blood vessel is not always an easy task, especially with patients that present atypical anatomy or suffer from conditions such as weak pulsation or obesity that make vascular localization difficult. With recent advances in fiber optic sensors, there is an opportunity to develop a new tool that can make vascular localization safer and easier. In this work, the authors present a new fiber Bragg grating (FBG) based vascular access device that specializes in arterial localization. The device estimates the location towards a local artery based on the bending of a needle inserted near the tissue surrounding the artery. Experimental results obtained from an artificial circulatory loop and a mock artery show the device works best for lower angles of needle insertion and can provide an approximately 40° range of estimation towards the location of a pulsating source (e.g. an artery).

Kinematics of mechanical and adhesional micromanipulation under a scanning electron microscope

NASA Astrophysics Data System (ADS)

Saito, Shigeki; Miyazaki, Hideki T.; Sato, Tomomasa; Takahashi, Kunio

2002-11-01

In this paper, the kinematics of mechanical and adhesional micromanipulation using a needle-shaped tool under a scanning electron microscope is analyzed. A mode diagram is derived to indicate the possible micro-object behavior for the specified operational conditions. Based on the diagram, a reasonable method for pick and place operation is proposed. The keys to successful analysis are to introduce adhesional and rolling-resistance factors into the kinematic system consisting of a sphere, a needle-shaped tool, and a substrate, and to consider the time dependence of these factors due to the electron-beam (EB) irradiation. Adhesional force and the lower limit of maximum rolling resistance are evaluated quantitatively in theoretical and experimental ways. This analysis shows that it is possible to control the fracture of either the tool-sphere or substrate-sphere interface of the system selectively by the tool-loading angle and that such a selective fracture of the interfaces enables reliable pick or place operation even under EB irradiation. Although the conventional micromanipulation was not repeatable because the technique was based on an empirically effective method, this analysis should provide us with a guideline to reliable micromanipulation.

Recovering Infectious HIV from Novel Syringe-Needle Combinations with Low Dead Space Volumes.

PubMed

Abdala, Nadia; Patel, Amisha; Heimer, Robert

This study determines if detachable syringe-needle combinations redesigned to reduce their dead space volume may substantially reduce the burden of exposure to infectious HIV among people who inject drugs. Two novel, low dead space (LDS) syringe-needle designs-one added a piston to the plunger (LDS syringe) and the other added a filler to the needle (LDS needle) to reduce their dead space-were compared to standard detachable needle-syringe combinations and to syringes with fixed needles. LDS and standard syringes attached to LDS and standard needles of 23-, 25-, and 27-gauge size were contaminated with HIV-infected blood in the laboratory. The proportion of syringe-needle combinations containing infectious HIV was analyzed after syringes were (1) stored up to 7 days at 22°C or (2) rinsed with water. Detachable syringes attached to 25-gauge needles yielded comparable proportions of syringes with infectious HIV, whether the needle was standard or LDS. Among needles of greater diameter (23 gauge), LDS needles tended to reduce recoverable HIV to a greater extent than standard needles. Syringes with fixed needles showed superior results to LDS syringes attached to needles of equivalent diameter and were less likely to get clogged by blood. Detachable LDS syringe-needle designs must be recommended with caution since they still pose potential risk for HIV transmission. Distribution of LDS syringes and needles must be accompanied by recommendations and instructions for their proper rinsing and disinfection in order to reduce viral burden and chances of needle clogging.

ULTRASONIC FLAW DETECTION METHOD AND MEANS

DOEpatents

Worlton, D.C.

1961-08-15

A method of detecting subsurface flaws in an object using ultrasonic waves is described. An ultnasonic wave of predetermined velocity and frequency is transmitted to engage the surface of the object at a predetermined angle of inci dence thereto. The incident angle of the wave to the surface is determined with respect to phase velocity, incident wave velocity, incident wave frequency, and the estimated depth of the flaw so that Lamb waves of a particular type and mode are induced only in the portion of the object between the flaw and the surface. These Lamb waves are then detected as they leave the object at an angle of exit equal to the angle of incidence. No waves wlll be generated in the object and hence received if no flaw exists beneath the surface. (AEC)

Data acquisition and processing system and method for investigating sub-surface features of a rock formation

DOEpatents

Vu, Cung Khac; Nihei, Kurt; Johnson, Paul A; Guyer, Robert; Ten Cate, James A; Le Bas, Pierre-Yves; Larmat, Carene S

2015-01-27

A system and a method includes generating a first signal at a first frequency; and a second signal at a second frequency. Respective sources are positioned within the borehole and controllable such that the signals intersect in an intersection volume outside the borehole. A receiver detects a difference signal returning to the borehole generated by a non-linear mixing process within the intersection volume, and records the detected signal and stores the detected signal in a storage device and records measurement parameters including a position of the first acoustic source, a position of the second acoustic source, a position of the receiver, elevation angle and azimuth angle of the first acoustic signal and elevation angle and azimuth angle of the second acoustic signal.

Accidental needle sticks, the Occupational Safety and Health Administration, and the fallacy of public policy.

PubMed

Wolf, Bruce L; Marks, Albert; Fahrenholz, John M

2006-07-01

Current Occupational Safety and Health Administration (OSHA) guidelines mandate the use of safety needles when allergy injections are given. Safety needles for intradermal testing remain optional. Whether safety needles reduce the number of accidental needle sticks (ANSs) in the outpatient setting has yet to be proven. To determine the rate of ANSs with new (safety) needles vs old needles used in allergy immunotherapy and intradermal testing. Allergy practices from 22 states were surveyed by e-mail. Seventy practices (28%) responded to the survey. Twice as many ANSs occurred in practices giving immunotherapy when using new needles vs old needles (P < .01). The rate of ANSs was roughly the same for intradermal testing with new needles vs old needles. These findings further question whether OSHA's guidelines for safety needle use in outpatient practice need revision and if allergy practices might be excluded from the requirement to use safety needles.

Methods specification for diagnostic test accuracy studies in fine-needle aspiration cytology: a survey of reporting practice.

PubMed

Schmidt, Robert L; Factor, Rachel E; Affolter, Kajsa E; Cook, Joshua B; Hall, Brian J; Narra, Krishna K; Witt, Benjamin L; Wilson, Andrew R; Layfield, Lester J

2012-01-01

Diagnostic test accuracy (DTA) studies on fine-needle aspiration cytology (FNAC) often show considerable variability in diagnostic accuracy between study centers. Many factors affect the accuracy of FNAC. A complete description of the testing parameters would help make valid comparisons between studies and determine causes of performance variation. We investigated the manner in which test conditions are specified in FNAC DTA studies to determine which parameters are most commonly specified and the frequency with which they are specified and to see whether there is significant variability in reporting practice. We identified 17 frequently reported test parameters and found significant variation in the reporting of these test specifications across studies. On average, studies reported 5 of the 17 items that would be required to specify the test conditions completely. A more complete and standardized reporting of methods, perhaps by means of a checklist, would improve the interpretation of FNAC DTA studies.

Effectiveness of Toyota process redesign in reducing thyroid gland fine-needle aspiration error.

PubMed

Raab, Stephen S; Grzybicki, Dana Marie; Sudilovsky, Daniel; Balassanian, Ronald; Janosky, Janine E; Vrbin, Colleen M

2006-10-01

Our objective was to determine whether the Toyota Production System process redesign resulted in diagnostic error reduction for patients who underwent cytologic evaluation of thyroid nodules. In this longitudinal, nonconcurrent cohort study, we compared the diagnostic error frequency of a thyroid aspiration service before and after implementation of error reduction initiatives consisting of adoption of a standardized diagnostic terminology scheme and an immediate interpretation service. A total of 2,424 patients underwent aspiration. Following terminology standardization, the false-negative rate decreased from 41.8% to 19.1% (P = .006), the specimen nondiagnostic rate increased from 5.8% to 19.8% (P < .001), and the sensitivity increased from 70.2% to 90.6% (P < .001). Cases with an immediate interpretation had a lower noninterpretable specimen rate than those without immediate interpretation (P < .001). Toyota process change led to significantly fewer diagnostic errors for patients who underwent thyroid fine-needle aspiration.

Fine-needle aspiration in the diagnosis of equine skin disease and the epidemiology of equine skin cytology submissions in a western Canadian diagnostic laboratory.

PubMed

Zachar, Erin K; Burgess, Hilary J; Wobeser, Bruce K

2016-06-01

Fine-needle aspiration (FNA) is commonly used to diagnose skin disease in companion animals, but its use in horses appears to be infrequent. Equine veterinarians in western Canada were surveyed to determine their opinions about FNA and 15 years of diagnostic submissions were used to compare the perceived to actual value of FNA in the diagnosis of skin disease in horses. Practitioners viewed FNA as quick, easy, economical, and minimally invasive. However, most veterinarians rarely chose to use FNA due to a perception that sample quality and diagnostic yield were poor and there was a narrow range of diseases the technique could diagnose. Analysis of the FNA cytology samples from a veterinary diagnostic laboratory showed a wide variety of equine skin disease conditions, but the frequency of non-diagnostic results was significantly higher in equine submissions compared to those from dogs and cats.

Magnetic actuation and feedback cooling of a cavity optomechanical torque sensor.

PubMed

Kim, P H; Hauer, B D; Clark, T J; Fani Sani, F; Freeman, M R; Davis, J P

2017-11-07

Cavity optomechanics has demonstrated remarkable capabilities, such as measurement and control of mechanical motion at the quantum level. Yet many compelling applications of optomechanics-such as microwave-to-telecom wavelength conversion, quantum memories, materials studies, and sensing applications-require hybrid devices, where the optomechanical system is coupled to a separate, typically condensed matter, system. Here, we demonstrate such a hybrid optomechanical system, in which a mesoscopic ferromagnetic needle is integrated with an optomechanical torsional resonator. Using this system we quantitatively extract the magnetization of the needle, not known a priori, demonstrating the potential of this system for studies of nanomagnetism. Furthermore, we show that we can magnetically dampen its torsional mode from room-temperature to 11.6 K-improving its mechanical response time without sacrificing torque sensitivity. Future extensions will enable studies of high-frequency spin dynamics and broadband wavelength conversion via torque mixing.

Calculation of gas turbine characteristic

NASA Astrophysics Data System (ADS)

Mamaev, B. I.; Murashko, V. L.

2016-04-01

The reasons and regularities of vapor flow and turbine parameter variation depending on the total pressure drop rate π* and rotor rotation frequency n are studied, as exemplified by a two-stage compressor turbine of a power-generating gas turbine installation. The turbine characteristic is calculated in a wide range of mode parameters using the method in which analytical dependences provide high accuracy for the calculated flow output angle and different types of gas dynamic losses are determined with account of the influence of blade row geometry, blade surface roughness, angles, compressibility, Reynolds number, and flow turbulence. The method provides satisfactory agreement of results of calculation and turbine testing. In the design mode, the operation conditions for the blade rows are favorable, the flow output velocities are close to the optimal ones, the angles of incidence are small, and the flow "choking" modes (with respect to consumption) in the rows are absent. High performance and a nearly axial flow behind the turbine are obtained. Reduction of the rotor rotation frequency and variation of the pressure drop change the flow parameters, the parameters of the stages and the turbine, as well as the form of the characteristic. In particular, for decreased n, nonmonotonic variation of the second stage reactivity with increasing π* is observed. It is demonstrated that the turbine characteristic is mainly determined by the influence of the angles of incidence and the velocity at the output of the rows on the losses and the flow output angle. The account of the growing flow output angle due to the positive angle of incidence for decreased rotation frequencies results in a considerable change of the characteristic: poorer performance, redistribution of the pressure drop at the stages, and change of reactivities, growth of the turbine capacity, and change of the angle and flow velocity behind the turbine.

Compact flexible multifrequency splitter based on plasmonic graded metallic grating arc waveguide.

PubMed

Han, Chao; Wang, Zhaohong; Chu, Yangyang; Zhao, Xiaodan; Zhang, Xuanru

2018-04-15

A compact flexible multifrequency splitter based on an arc waveguide constructed of plasmonic metallic grating structures with graded-height T-grooves is proposed and studied. The dispersion curves and cutoff frequencies of the plasmonic grating waveguides with different T-groove metallic grating heights are different. The guided spoof surface plasmonic polariton waves at different frequencies can be localized at dissimilar angles along the graded grating arc waveguide. The output flexibility at an arbitrary groove for different frequencies is realized by introducing an additional symmetrical T-groove structure as an output. The compact four-, seven-, and eight-output frequency splitters demonstrate its flexible multifrequency separation capability at different output angle locations, while the dimensional size of the frequency splitters is not increased. Measurement results at the microwave frequency display excellent agreement with numerical simulation results.

Optical Interactions at Randomly Rough Surfaces

DTIC Science & Technology

2003-03-10

frequency range. The design of a random surface that acts as a Lambertian diffuser, especially in the infrared region of the optical spectrum, is...FTIR grazing angle microscopy. Recently, an experimental study was performed of the far-field scattering at small grazing angles, especially the enhanced...a specular component in the scattered light, in this frequency range. The design of a random surface that acts as a Lambertian diffuser, especially in

Twisted MoSe 2 bilayers with variable local stacking and interlayer coupling revealed by low-frequency Raman spectroscopy

DOE PAGES

Puretzky, Alexander A.; Liang, Liangbo; Li, Xufan; ...

2016-01-14

Unique twisted bilayers of MoSe 2 with multiple stacking orientations and interlayer couplings in the narrow range of twist angles, 60 ± 3°, are revealed by low-frequency Raman spectroscopy and theoretical analysis. The slight deviation from 60 allows the concomitant presence of patches featuring all three high-symmetry stacking configurations (2H or AA', AB', A'B) in one unique bilayer system. In this case, the periodic arrangement of the patches and their size strongly depend on the twist angle. Ab initio modeling predicts significant changes in frequencies and intensities of low-frequency modes versus stacking and twist angle. Experimentally, the variable stacking andmore » coupling across the interface is revealed by the appearance of two breathing modes corresponding to the mixture of the high-symmetry stacking configurations and unaligned regions of monolayers. Only one breathing mode is observed outside the narrow range of twist angles. This indicates a stacking transition to unaligned monolayers with mismatched atom registry without the in-plane restoring force required to generate a shear mode. As a result, the variable interlayer coupling and spacing in transition metal dichalcogenide bilayers revealed in this study may provide a new platform for optoelectronic applications of these materials.« less

Twisted MoSe 2 bilayers with variable local stacking and interlayer coupling revealed by low-frequency Raman spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Puretzky, Alexander A.; Liang, Liangbo; Li, Xufan

Unique twisted bilayers of MoSe 2 with multiple stacking orientations and interlayer couplings in the narrow range of twist angles, 60 ± 3°, are revealed by low-frequency Raman spectroscopy and theoretical analysis. The slight deviation from 60 allows the concomitant presence of patches featuring all three high-symmetry stacking configurations (2H or AA', AB', A'B) in one unique bilayer system. In this case, the periodic arrangement of the patches and their size strongly depend on the twist angle. Ab initio modeling predicts significant changes in frequencies and intensities of low-frequency modes versus stacking and twist angle. Experimentally, the variable stacking andmore » coupling across the interface is revealed by the appearance of two breathing modes corresponding to the mixture of the high-symmetry stacking configurations and unaligned regions of monolayers. Only one breathing mode is observed outside the narrow range of twist angles. This indicates a stacking transition to unaligned monolayers with mismatched atom registry without the in-plane restoring force required to generate a shear mode. As a result, the variable interlayer coupling and spacing in transition metal dichalcogenide bilayers revealed in this study may provide a new platform for optoelectronic applications of these materials.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siauw, Timmy; Cunha, Adam; Berenson, Dmitry

Purpose: In this study, the authors introduce skew line needle configurations for high dose rate (HDR) brachytherapy and needle planning by integer program (NPIP), a computational method for generating these configurations. NPIP generates needle configurations that are specific to the anatomy of the patient, avoid critical structures near the penile bulb and other healthy structures, and avoid needle collisions inside the body. Methods: NPIP consisted of three major components: a method for generating a set of candidate needles, a needle selection component that chose a candidate needle subset to be inserted, and a dose planner for verifying that the finalmore » needle configuration could meet dose objectives. NPIP was used to compute needle configurations for prostate cancer data sets from patients previously treated at our clinic. NPIP took two user-parameters: a number of candidate needles, and needle coverage radius, {delta}. The candidate needle set consisted of 5000 needles, and a range of {delta} values was used to compute different needle configurations for each patient. Dose plans were computed for each needle configuration. The number of needles generated and dosimetry were analyzed and compared to the physician implant. Results: NPIP computed at least one needle configuration for every patient that met dose objectives, avoided healthy structures and needle collisions, and used as many or fewer needles than standard practice. These needle configurations corresponded to a narrow range of {delta} values, which could be used as default values if this system is used in practice. The average end-to-end runtime for this implementation of NPIP was 286 s, but there was a wide variation from case to case. Conclusions: The authors have shown that NPIP can automatically generate skew line needle configurations with the aforementioned properties, and that given the correct input parameters, NPIP can generate needle configurations which meet dose objectives and use as many or fewer needles than the current HDR brachytherapy workflow. Combined with robot assisted brachytherapy, this system has the potential to reduce side effects associated with treatment. A physical trial should be done to test the implant feasibility of NPIP needle configurations.« less

Impact of Offshore Wind Power Integrated by VSC-HVDC on Power Angle Stability of Power Systems

NASA Astrophysics Data System (ADS)

Lu, Haiyang; Tang, Xisheng

2017-05-01

Offshore wind farm connected to grid by VSC-HVDC loses frequency support for power system, so adding frequency control in wind farm and VSC-HVDC system is an effective measure, but it will change wind farm VSC-HVDC’s transient stability on power system. Through theoretical analysis, concluding the relationship between equivalent mechanical power and electromagnetic power of two-machine system with the active power of wind farm VSC-HVDC, then analyzing the impact of wind farm VSC-HVDC with or without frequency control and different frequency control parameters on angle stability of synchronous machine by EEAC. The validity of theoretical analysis has been demonstrated through simulation in PSCAD/EMTDC.

Comparison of Spinal Needle Deflection in a Ballistic Gel Model.

PubMed

Rand, Ethan; Christolias, George; Visco, Christopher; R Singh, Jaspal

2016-10-01

Percutaneous diagnostic and therapeutic procedures are commonly used in the treatment of spinal pain. The success of these procedures depends on the accuracy of needle placement, which is influenced by needle size and shape. The purpose of this study is to examine and quantify the deviation of commonly used spinal needles based on needle tip design and gauge, using a ballistic gel tissue simulant. Six needles commonly used in spinal procedures (Quincke, Short Bevel, Chiba, Tuohy, Hustead, Whitacre) were selected for use in this study. Ballistic gel samples were made in molds of two depths, 40mm and 80 mm. Each needle was mounted in a drill press to ensure an accurate needle trajectory. Distance of deflection was recorded for each needle. In comparing the mean deflection of 22 gauge needles of all types at 80 mm of depth, deflection was greatest among beveled needles [Short Bevel (9.96 ± 0.77 mm), Quincke (8.89 ± 0.17 mm), Chiba (7.71 ± 1.16 mm)], moderate among epidural needles [Tuohy (7.64 ± 0.16 mm) and least among the pencil-point needles [Whitacre (0.73 ± 0.34 mm)]. Increased gauge (25 g) led to a significant increase in deflection among beveled needles. The direction of deflection was away from the bevel with Quincke, Chiba and Short Beveled needles and toward the bevel of the Tuohy and Hustead needles. Deflection of the Whitacre pencil-point needle was minimal. There is clinical utility in knowing the relative deflection of various needle tips. When a procedure requires a needle to be steered around obstacles, or along non-collinear targets, the predictable and large amount of deflection obtained through use of a beveled spinal needle may prove beneficial.

Comparison of Spinal Needle Deflection in a Ballistic Gel Model

PubMed Central

Rand, Ethan; Christolias, George; Visco, Christopher; R. Singh, Jaspal

2016-01-01

Background Percutaneous diagnostic and therapeutic procedures are commonly used in the treatment of spinal pain. The success of these procedures depends on the accuracy of needle placement, which is influenced by needle size and shape. Objectives The purpose of this study is to examine and quantify the deviation of commonly used spinal needles based on needle tip design and gauge, using a ballistic gel tissue simulant. Materials and Methods Six needles commonly used in spinal procedures (Quincke, Short Bevel, Chiba, Tuohy, Hustead, Whitacre) were selected for use in this study. Ballistic gel samples were made in molds of two depths, 40mm and 80 mm. Each needle was mounted in a drill press to ensure an accurate needle trajectory. Distance of deflection was recorded for each needle. Results In comparing the mean deflection of 22 gauge needles of all types at 80 mm of depth, deflection was greatest among beveled needles [Short Bevel (9.96 ± 0.77 mm), Quincke (8.89 ± 0.17 mm), Chiba (7.71 ± 1.16 mm)], moderate among epidural needles [Tuohy (7.64 ± 0.16 mm) and least among the pencil-point needles [Whitacre (0.73 ± 0.34 mm)]. Increased gauge (25 g) led to a significant increase in deflection among beveled needles. The direction of deflection was away from the bevel with Quincke, Chiba and Short Beveled needles and toward the bevel of the Tuohy and Hustead needles. Deflection of the Whitacre pencil-point needle was minimal. Conclusions There is clinical utility in knowing the relative deflection of various needle tips. When a procedure requires a needle to be steered around obstacles, or along non-collinear targets, the predictable and large amount of deflection obtained through use of a beveled spinal needle may prove beneficial. PMID:27847693

Improvement of Depth Profiling into Biotissues Using Micro Electrical Impedance Spectroscopy on a Needle with Selective Passivation

PubMed Central

Yun, Joho; Kim, Hyeon Woo; Lee, Jong-Hyun

2016-01-01

A micro electrical impedance spectroscopy (EIS)-on-a-needle for depth profiling (μEoN-DP) with a selective passivation layer (SPL) on a hypodermic needle was recently fabricated to measure the electrical impedance of biotissues along with the penetration depths. The SPL of the μEoN-DP enabled the sensing interdigitated electrodes (IDEs) to contribute predominantly to the measurement by reducing the relative influence of the connection lines on the sensor output. The discrimination capability of the μEoN-DP was verified using phosphate-buffered saline (PBS) at various concentration levels. The resistance and capacitance extracted through curve fitting were similar to those theoretically estimated based on the mixing ratio of PBS and deionized water; the maximum discrepancies were 8.02% and 1.85%, respectively. Depth profiling was conducted using four-layered porcine tissue to verify the effectiveness of the discrimination capability of the μEoN-DP. The magnitude and phase between dissimilar porcine tissues (fat and muscle) were clearly discriminated at the optimal frequency of 1 MHz. Two kinds of simulations, one with SPL and the other with complete passivation layer (CPL), were performed, and it was verified that the SPL was advantageous over CPL in the discrimination of biotissues in terms of sensor output. PMID:28009845

Improvement of Depth Profiling into Biotissues Using Micro Electrical Impedance Spectroscopy on a Needle with Selective Passivation.

PubMed

Yun, Joho; Kim, Hyeon Woo; Lee, Jong-Hyun

2016-12-21

A micro electrical impedance spectroscopy (EIS)-on-a-needle for depth profiling (μEoN-DP) with a selective passivation layer (SPL) on a hypodermic needle was recently fabricated to measure the electrical impedance of biotissues along with the penetration depths. The SPL of the μEoN-DP enabled the sensing interdigitated electrodes (IDEs) to contribute predominantly to the measurement by reducing the relative influence of the connection lines on the sensor output. The discrimination capability of the μEoN-DP was verified using phosphate-buffered saline (PBS) at various concentration levels. The resistance and capacitance extracted through curve fitting were similar to those theoretically estimated based on the mixing ratio of PBS and deionized water; the maximum discrepancies were 8.02% and 1.85%, respectively. Depth profiling was conducted using four-layered porcine tissue to verify the effectiveness of the discrimination capability of the μEoN-DP. The magnitude and phase between dissimilar porcine tissues (fat and muscle) were clearly discriminated at the optimal frequency of 1 MHz. Two kinds of simulations, one with SPL and the other with complete passivation layer (CPL), were performed, and it was verified that the SPL was advantageous over CPL in the discrimination of biotissues in terms of sensor output.

A comparison of the community diversity of foliar fungal endophytes between seedling and adult loblolly pines (Pinus taeda)

PubMed Central

Oono, Ryoko; Lefèvre, Emilie; Simha, Anita; Lutzoni, François

2015-01-01

Fungal endophytes represent one of the most ubiquitous plant symbionts on Earth and are phylogenetically diverse. The structure and diversity of endophyte communities have been shown to depend on host taxa and climate, but there have been relatively few studies exploring endophyte communities throughout host maturity. We compared foliar fungal endophyte communities between seedlings and adult trees of loblolly pines (Pinus taeda) at the same seasons and locations by culturing and culture-independent methods. We sequenced the internal transcribed spacer region and adjacent partial large subunit nuclear ribosomal RNA gene (ITS–LSU amplicon) to delimit operational taxonomic units and phylogenetically characterize the communities. Despite the lower infection frequency in seedlings compared to adult trees, seedling needles were receptive to a more diverse community of fungal endophytes. Culture-free method confirmed the presence of commonly cultured OTUs from adult needles but revealed several new OTUs from seedling needles that were not found with culturing methods. The two most commonly cultured OTUs in adults were rarely cultured from seedlings, suggesting that host age is correlated with a selective enrichment for specific endophytes. This shift in endophyte species dominance may be indicative of a functional change between these fungi and their loblolly pine hosts. PMID:26399186

Investigation of the piezoelectric thimble tactile device operating modes.

PubMed

Bansevicius, Ramutis; Dragasius, Egidijus; Grigas, Vytautas; Jurenas, Vytautas; Mazeika, Darius; Zvironas, Arunas

2014-01-01

A multifunctional device to transfer graphical or text information for blind or visually impaired is presented. The prototype using tactile perception has been designed where information displayed on the screen of electronic device (mobile phone, PC) is transferred by oscillating needle, touching the fingertip. Having the aim to define optimal parameters of the fingertip excitation by needle, the computational analysis of different excitation modes has been carried out. A 3D solid computational finite element model of the skin segment, comprising four main fingertip skin layers (stratum corneum, epidermis, dermis and hypodermis) was built by using ANSYS Workbench FEA software. Harmonic analysis of its stress-strain state under excitation with different frequency (up to 10000 Hz) and harmonic force (0.01 N), acting outer stratum corneum layer in normal direction at one, two or three points has been performed. The influence of the mode of dynamic loading of skin was evaluated (in terms of the tactile signal level) on the basis of the normal and shear elastic strain in dermis, where mechanoreceptors are placed. It is shown that the tactile perception of information, delivered by three vibrating pins, may be influenced by configuration of excitation points (their number and phase of loading) and the frequency of excitation.

Magnetic Resonance Mediated Radiofrequency Ablation.

PubMed

Hue, Yik-Kiong; Guimaraes, Alexander R; Cohen, Ouri; Nevo, Erez; Roth, Abraham; Ackerman, Jerome L

2018-02-01

To introduce magnetic resonance mediated radiofrequency ablation (MR-RFA), in which the MRI scanner uniquely serves both diagnostic and therapeutic roles. In MR-RFA scanner-induced RF heating is channeled to the ablation site via a Larmor frequency RF pickup device and needle system, and controlled via the pulse sequence. MR-RFA was evaluated with simulation of electric and magnetic fields to predict the increase in local specific-absorption-rate (SAR). Temperature-time profiles were measured for different configurations of the device in agar phantoms and ex vivo bovine liver in a 1.5 T scanner. Temperature rise in MR-RFA was imaged using the proton resonance frequency method validated with fiber-optic thermometry. MR-RFA was performed on the livers of two healthy live pigs. Simulations indicated a near tenfold increase in SAR at the RFA needle tip. Temperature-time profiles depended significantly on the physical parameters of the device although both configurations tested yielded temperature increases sufficient for ablation. Resected livers from live ablations exhibited clear thermal lesions. MR-RFA holds potential for integrating RF ablation tumor therapy with MRI scanning. MR-RFA may add value to MRI with the addition of a potentially disposable ablation device, while retaining MRI's ability to provide real time procedure guidance and measurement of tissue temperature, perfusion, and coagulation.

Detection of mitochondrial DNA mutations in primary breast cancer and fine-needle aspirates.

PubMed

Parrella, P; Xiao, Y; Fliss, M; Sanchez-Cespedes, M; Mazzarelli, P; Rinaldi, M; Nicol, T; Gabrielson, E; Cuomo, C; Cohen, D; Pandit, S; Spencer, M; Rabitti, C; Fazio, V M; Sidransky, D

2001-10-15

To determine the frequency and distribution of mitochondrial DNA mutations in breast cancer, 18 primary breast tumors were analyzed by direct sequencing. Twelve somatic mutations not present in matched lymphocytes and normal breast tissues were detected in 11 of the tumors screened (61%). Of these mutations, five (42%) were deletions or insertions in a homopolymeric C-stretch between nucleotides 303-315 (D310) within the D-loop. The remaining seven mutations (58%) were single-base substitutions in the coding (ND1, ND4, ND5, and cytochrome b genes) or noncoding regions (D-loop) of the mitochondrial genome. In three cases (25%), the mutations detected in coding regions led to amino acid substitutions in the protein sequence. We then screened an additional 46 primary breast tumors with a rapid PCR-based assay to identify poly-C alterations in D310, and we found seven more cancers with alterations. Using D310 mutations as clonal marker, we detected identical changes in five of five matched fine-needle aspirates and in four of four metastases-positive lymph nodes. The high frequency of D310 alterations in primary breast cancer combined with the high sensitivity of the PCR-based assays provides a new molecular tool for cancer detection.

Automatic Robotic Steering of Flexible Needles from 3D Ultrasound Images in Phantoms and Ex Vivo Biological Tissue.

PubMed

Mignon, Paul; Poignet, Philippe; Troccaz, Jocelyne

2018-05-29

Robotic control of needle bending aims at increasing the precision of percutaneous procedures. Ultrasound feedback is preferable for its clinical ease of use, cost and compactness but raises needle detection issues. In this paper, we propose a complete system dedicated to robotized guidance of a flexible needle under 3D ultrasound imaging. This system includes a medical robot dedicated to transperineal needle positioning and insertion, a rapid path planning for needle steering using bevel-tip needle natural curvature in tissue, and an ultrasound-based automatic needle detection algorithm. Since ultrasound-based automatic needle steering is often made difficult by the needle localization in biological tissue, we quantify the benefit of using flexible echogenic needles for robotized guidance under 3D ultrasound. The "echogenic" term refers to the etching of microstructures on the needle shaft. We prove that these structures improve needle visibility and detection robustness in ultrasound images. We finally present promising results when reaching targets using needle steering. The experiments were conducted with various needles in different media (synthetic phantoms and ex vivo biological tissue). For instance, with nitinol needles the mean accuracy is 1.2 mm (respectively 3.8 mm) in phantoms (resp. biological tissue).

Low-Frequency Waves in Cold Three-Component Plasmas

NASA Astrophysics Data System (ADS)

Fu, Qiang; Tang, Ying; Zhao, Jinsong; Lu, Jianyong

2016-09-01

The dispersion relation and electromagnetic polarization of the plasma waves are comprehensively studied in cold electron, proton, and heavy charged particle plasmas. Three modes are classified as the fast, intermediate, and slow mode waves according to different phase velocities. When plasmas contain positively-charged particles, the fast and intermediate modes can interact at the small propagating angles, whereas the two modes are separate at the large propagating angles. The near-parallel intermediate and slow waves experience the linear polarization, circular polarization, and linear polarization again, with the increasing wave number. The wave number regime corresponding to the above circular polarization shrinks as the propagating angle increases. Moreover, the fast and intermediate modes cause the reverse change of the electromagnetic polarization at the special wave number. While the heavy particles carry the negative charges, the dispersion relations of the fast and intermediate modes are always separate, being independent of the propagating angles. Furthermore, this study gives new expressions of the three resonance frequencies corresponding to the highly-oblique propagation waves in the general three-component plasmas, and shows the dependence of the resonance frequencies on the propagating angle, the concentration of the heavy particle, and the mass ratio among different kinds of particles. supported by National Natural Science Foundation of China (Nos. 11303099, 41531071 and 41574158), and the Youth Innovation Promotion Association CAS

Study of Wave-Particle Interactions for Whistler Mode Waves at Oblique Angles by Utilizing the Gyroaveraging Method

NASA Astrophysics Data System (ADS)

Hsieh, Yi-Kai; Omura, Yoshiharu

2017-10-01

We investigate the properties of whistler mode wave-particle interactions at oblique wave normal angles to the background magnetic field. We find that electromagnetic energy of waves at frequencies below half the electron cyclotron frequency can flow nearly parallel to the ambient magnetic field. We thereby confirm that the gyroaveraging method, which averages the cyclotron motion to the gyrocenter and reduces the simulation from two-dimensional to one-dimensional, is valid for oblique wave-particle interaction. Multiple resonances appear for oblique propagation but not for parallel propagation. We calculate the possible range of resonances with the first-order resonance condition as a function of electron kinetic energy and equatorial pitch angle. To reveal the physical process and the efficiency of electron acceleration by multiple resonances, we assume a simple uniform wave model with constant amplitude and frequency in space and time. We perform test particle simulations with electrons starting at specific equatorial pitch angles and kinetic energies. The simulation results show that multiple resonances contribute to acceleration and pitch angle scattering of energetic electrons. Especially, we find that electrons with energies of a few hundred keV can be accelerated efficiently to a few MeV through the n = 0 Landau resonance.

A novel adaptive needle insertion sequencing for robotic, single needle MR-guided high-dose-rate prostate brachytherapy

NASA Astrophysics Data System (ADS)

Borot de Battisti, M.; de Senneville, B. Denis; Hautvast, G.; Binnekamp, D.; Lagendijk, J. J. W.; Maenhout, M.; Moerland, M. A.

2017-05-01

MR-guided high-dose-rate (HDR) brachytherapy has gained increasing interest as a treatment for patients with localized prostate cancer because of the superior value of MRI for tumor and surrounding tissues localization. To enable needle insertion into the prostate with the patient in the MR bore, a single needle MR-compatible robotic system involving needle-by-needle dose delivery has been developed at our institution. Throughout the intervention, dose delivery may be impaired by: (1) sub-optimal needle positioning caused by e.g. needle bending, (2) intra-operative internal organ motion such as prostate rotations or swelling, or intra-procedural rectum or bladder filling. This may result in failure to reach clinical constraints. To assess the first aforementioned challenge, a recent study from our research group demonstrated that the deposited dose may be greatly improved by real-time adaptive planning with feedback on the actual needle positioning. However, the needle insertion sequence is left to the doctor and therefore, this may result in sub-optimal dose delivery. In this manuscript, a new method is proposed to determine and update automatically the needle insertion sequence. This strategy is based on the determination of the most sensitive needle track. The sensitivity of a needle track is defined as its impact on the dose distribution in case of sub-optimal positioning. A stochastic criterion is thus presented to determine each needle track sensitivity based on needle insertion simulations. To assess the proposed sequencing strategy, HDR prostate brachytherapy was simulated on 11 patients with varying number of needle insertions. Sub-optimal needle positioning was simulated at each insertion (modeled by typical random angulation errors). In 91% of the scenarios, the dose distribution improved when the needle was inserted into the most compared to the least sensitive needle track. The computation time for sequencing was less than 6 s per needle track. The proposed needle insertion sequencing can therefore assist in delivering an optimal dose in HDR prostate brachytherapy.

Influence of spin creepage and contact angle on curve squeal: A numerical approach

NASA Astrophysics Data System (ADS)

Zenzerovic, I.; Kropp, W.; Pieringer, A.

2018-04-01

Curve squeal is a loud tonal sound that may arise when a railway vehicle negotiates a tight curve. Due to the nonlinear nature of squeal, time-domain models provide a higher degree of accuracy in comparison to frequency-domain models and also enable the determination of squeal amplitudes. In the present paper, a previously developed engineering time-domain model for curve squeal is extended to include the effects of the contact angle and spin creepage. The extensions enable the evaluation of more realistic squeal cases with the computationally efficient model. The model validation against Kalker's variational contact model shows good agreement between the models. Results of studies on the influence of spin creepage and contact angle show that the contact angle has a significant influence on the vertical-lateral dynamics coupling and, therefore, influences both squeal amplitude and frequency. Spin creepage mainly influences processes in the contact, therefore influencing the tangential contact force amplitude. In the combined spin-contact angle study the spin creepage value is kinematically related to the contact angle value. Results indicate that the influence of the contact angle is dominant over the influence of spin creepage. In general, results indicate that the most crucial factors in squeal are those that influence the dynamics coupling: the contact angle, wheel/rail contact positions and friction.

Combination of water-jet dissection and needle-knife as a hybrid knife simplifies endoscopic submucosal dissection.

PubMed

Lingenfelder, Tobias; Fischer, Klaus; Sold, Moritz G; Post, Stefan; Enderle, Markus D; Kaehler, Georg F B A

2009-07-01

The safety and efficacy of endoscopic submucosal dissection (ESD) is very dependent on an effective injection beneath the submucosal lamina and on a controlled cutting technique. After our study group demonstrated the efficacy of the HydroJet in needleless submucosal injections under various physical conditions to create a submucosal fluid cushion (Selective tissue elevation by pressure = STEP technique), the next step was to develop a new instrument to combine the capabilities of an IT-Knife with a high-pressure water-jet in a single instrument. In this experimental study, we compared this new instrument with a standard ESD technique. Twelve gastric ESD were performed in six pigs under endotracheal anesthesia. Square areas measuring 4-cm x 4-cm were marked out on the anterior and posterior wall in the corpus-antrum transition region. The HybridKnife was used as an standard needle knife with insulated tip (i.e., the submucosal injection was performed with an injection needle and only the radiofrequency (RF) part of the HybridKnife was used for cutting (conventional technique)) or the HybridKnife was used in all the individual stages of the ESD, making use of the HybridKnife's combined functions (HybridKnife technique). The size of the resected specimens, the operating time, the frequency with which instruments were changed, the number of bleeding episodes, and the number of injuries to the gastric wall together with the subjective overall assessment of the intervention by the operating physician were recorded. The resected specimens were the same size, with average sizes of 16.96 cm(2) and 15.85 cm(2) resp (p = 0.8125). Bleeding episodes have been less frequent in the HybridKnife group (2.83 vs. 3.5; p = 0.5625). The standard knife caused more injuries to the lamina muscularis propria (0.17 vs. 1.33; p = 0.0313). The operating times had a tendency to be shorter with the HybridKnife technique (47.18 vs. 58.32 minute; p = 0.0313). The combination of a needle-knife with high-pressure water-jet dissection improved the results of endoscopic submucosal dissection in this experimental setting. Because the frequency of complications is still high, further improvements to the instrument are necessary.

TU-H-CAMPUS-JeP3-05: Adaptive Determination of Needle Sequence HDR Prostate Brachytherapy with Divergent Needle-By-Needle Delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borot de Battisti, M; Maenhout, M; Lagendijk, J J W

Purpose: To develop a new method which adaptively determines the optimal needle insertion sequence for HDR prostate brachytherapy involving divergent needle-by-needle dose delivery by e.g. a robotic device. A needle insertion sequence is calculated at the beginning of the intervention and updated after each needle insertion with feedback on needle positioning errors. Methods: Needle positioning errors and anatomy changes may occur during HDR brachytherapy which can lead to errors in the delivered dose. A novel strategy was developed to calculate and update the needle sequence and the dose plan after each needle insertion with feedback on needle positioning errors. Themore » dose plan optimization was performed by numerical simulations. The proposed needle sequence determination optimizes the final dose distribution based on the dose coverage impact of each needle. This impact is predicted stochastically by needle insertion simulations. HDR procedures were simulated with varying number of needle insertions (4 to 12) using 11 patient MR data-sets with PTV, prostate, urethra, bladder and rectum delineated. Needle positioning errors were modeled by random normally distributed angulation errors (standard deviation of 3 mm at the needle’s tip). The final dose parameters were compared in the situations where the needle with the largest vs. the smallest dose coverage impact was selected at each insertion. Results: Over all scenarios, the percentage of clinically acceptable final dose distribution improved when the needle selected had the largest dose coverage impact (91%) compared to the smallest (88%). The differences were larger for few (4 to 6) needle insertions (maximum difference scenario: 79% vs. 60%). The computation time of the needle sequence optimization was below 60s. Conclusion: A new adaptive needle sequence determination for HDR prostate brachytherapy was developed. Coupled to adaptive planning, the selection of the needle with the largest dose coverage impact increases chances of reaching the clinical constraints. M. Borot de Battisti is funded by Philips Medical Systems Nederland B.V.; M. Moerland is principal investigator on a contract funded by Philips Medical Systems Nederland B.V.; G. Hautvast and D. Binnekamp are fulltime employees of Philips Medical Systems Nederland B.V.« less

[Effects of slow twisting needle insertion and tubing needle insertion at Neiguan (PC 6) on cardiovascular function: a comparative study].

PubMed

Ning, Shaoli; Zhao, Lihua; Xu, Lingjun; Huang, Yu; Pang, Yong; Huang, Dingjian

2016-01-01

To compare the effects between slow twisting needle insertion and tubing needle insertion. With cross-over design, 100 healthy young subjects (half male and half female) aged from 19 to 23 years were randomly divided into two groups by random digital table, 50 cases in each one. At the first stage, subjects in the group A were treated with slow twisting needle insertion while, subjects in,the group B were treated with tubing needle insertion. One week later, the procedure of second stage was performed alternately. The needle was inserted into Neiguan (PC 6) with two methods by one acupuncturist. The needle was retained for 5 min before removal. Five min before needle insertion as well as needle withdrawal and 30 min after needle withdrawal, ZXG-E automatic cardiovascular diagnostic apparatus was used to test cardiovascular function. At the tim of needle withdrawal, slow twisting needle insertion could improve effect work of kinetics (EWK), effective blood volume (BV) and reduce elastic expansion coefficient of blood vessel (FEK) and left ventricular spray blood impedance (VER), which was significantly different from tubing needle insertion (all P < 0.05). Thirty min after needle withdrawal, the differences of the indices of cardiovascular function between the two groups were not significant (all P > 0.05). The slow twisting needle insertion is significantly superior to tubing needle insertion on lowering vascular tension and VER, improving EWK and BV.

Orthogonal design to sift the optimal parameter of Neiguan acupuncture for cerebral infarction

PubMed Central

Zhang, Yanan; Yang, Sha; Fan, Xiaonong; Wang, Shu; He, Nina; Li, Lingxin; Luo, Ding; Shi, Xuemin

2013-01-01

The individual difference and non-repeatability in acupuncture have not only restricted the development of acupuncture, but have also affected the specificity of acupoints. The present study used instruments to control needle depth, lifting and thrusting frequency, and the duration of acupuncture. Effects of the quantified acupuncture were observed at Neiguan (PC6) with different stimulation parameters. A frequency of 1, 2, or 3 Hz and duration of 5, 60, or 180 seconds were used to observe cerebral blood flow and ratio of infarct volume recovery. Results showed that stimulation at Neiguan with a frequency of 1 Hz and long duration of 180 seconds or 2/3 Hz and long duration of 5/60 seconds significantly increased cerebral blood flow and decreased the ratio of infarct volume. Interactions between frequency and duration play a critical role in quantified acupuncture therapy. PMID:25206575

Effect of ultrasonic cavitation on measurement of sound pressure using hydrophone

NASA Astrophysics Data System (ADS)

Thanh Nguyen, Tam; Asakura, Yoshiyuki; Okada, Nagaya; Koda, Shinobu; Yasuda, Keiji

2017-07-01

Effect of ultrasonic cavitation on sound pressure at the fundamental, second harmonic, and first ultraharmonic frequencies was investigated from low to high ultrasonic intensities. The driving frequencies were 22, 304, and 488 kHz. Sound pressure was measured using a needle-type hydrophone and ultrasonic cavitation was estimated from the broadband integrated pressure (BIP). With increasing square root of electric power applied to a transducer, the sound pressure at the fundamental frequency linearly increased initially, dropped at approximately the electric power of cavitation inception, and afterward increased again. The sound pressure at the second harmonic frequency was detected just below the electric power of cavitation inception. The first ultraharmonic component appeared at around the electric power of cavitation inception at 304 and 488 kHz. However, at 22 kHz, the first ultraharmonic component appeared at a higher electric power than that of cavitation inception.

[Needle breakage during mandibular block anaesthesia: prevention and retrieval].

PubMed

Baart, J A; van Amerongen, W E; de Jong, K J M; Allard, R H B

2006-12-01

Disposable needles for dental local anaesthesia do not break easily. Still, needle breakage does occur, and is mainly caused by unexpected movements of the patient or pre-use bending of the needle by the dentist. If a dental needle breaks while administering local anaesthesia, the dentist should prevent panic. If the patient opens his mouth wide the needle might still be visible. If so, the needle is removed. If the needle is no longer visible, the site where the needle has penetrated the mucosa should be marked with a permanent marker. The dentist will contact a maxillofacial surgeon for immediate consultation. The maxillofacial surgeon will try to retrieve the broken dental needle under general anaesthesia.

Behavior of Tip-Steerable Needles in ex vivo and in vivo Tissue

PubMed Central

Majewicz, Ann; Marra, Steven P.; van Vledder, Mark G.; Lin, MingDe; Choti, Michael A.; Song, Danny Y.; Okamura, Allison M.

2012-01-01

Robotic needle steering is a promising technique to improve the effectiveness of needle-based clinical procedures, such as biopsies and ablation, by computer-controlled, curved insertions of needles within solid organs. In this paper, we explore the capabilities, challenges, and clinical relevance of asymmetric-tip needle steering though experiments in ex vivo and in vivo tissue. We evaluate the repeatability of needle insertion in inhomogeneous biological tissue and compare ex vivo and in vivo needle curvature and insertion forces. Steerable needles curved more in kidney than in liver and prostate, likely due to differences in tissue properties. Pre-bent needles produced higher insertion forces in liver and more curvature in vivo than ex vivo. When compared to straight stainless steel needles, steerable needles did not cause a measurable increase in tissue damage and did not exert more force during insertion. The minimum radius of curvature achieved by pre-bent needles was 5.23 cm in ex vivo tissue, and 10.4 cm in in vivo tissue. The curvatures achieved by bevel tip needles were negligible for in vivo tissue. The minimum radius of curvature for bevel tip needles in ex vivo tissue was 16.4 cm; however, about half of the bevel tip needles had negligible curvatures. We also demonstrate a potential clinical application of needle steering by targeting and ablating overlapping regions of cadaveric canine liver. PMID:22711767

Fusion of electromagnetic trackers to improve needle deflection estimation: simulation study.

PubMed

Sadjadi, Hossein; Hashtrudi-Zaad, Keyvan; Fichtinger, Gabor

2013-10-01

We present a needle deflection estimation method to anticipate needle bending during insertion into deformable tissue. Using limited additional sensory information, our approach reduces the estimation error caused by uncertainties inherent in the conventional needle deflection estimation methods. We use Kalman filters to combine a kinematic needle deflection model with the position measurements of the base and the tip of the needle taken by electromagnetic (EM) trackers. One EM tracker is installed on the needle base and estimates the needle tip position indirectly using the kinematic needle deflection model. Another EM tracker is installed on the needle tip and estimates the needle tip position through direct, but noisy measurements. Kalman filters are then employed to fuse these two estimates in real time and provide a reliable estimate of the needle tip position, with reduced variance in the estimation error. We implemented this method to compensate for needle deflection during simulated needle insertions and performed sensitivity analysis for various conditions. At an insertion depth of 150 mm, we observed needle tip estimation error reductions in the range of 28% (from 1.8 to 1.3 mm) to 74% (from 4.8 to 1.2 mm), which demonstrates the effectiveness of our method, offering a clinically practical solution.

Dynamic mechanical analysis of fiber reinforced composites

NASA Technical Reports Server (NTRS)

Reed, K. E.

1979-01-01

Dynamic mechanical and thermal properties were determined for unidirectional epoxy/glass composites at various fiber orientation angles. Resonant frequency and relative logarithmic decrement were measured as functions of temperature. In low angle and longitudinal specimens a transition was observed above the resin glass transition temperature which was manifested mechanically as an additional damping peak and thermally as a change in the coefficient of thermal expansion. The new transition was attributed to a heterogeneous resin matrix induced by the fiber. The temperature span of the glass-rubber relaxation was found to broaden with decreasing orientation angle, reflecting the growth of fiber contribution and exhibiting behavior similar to that of Young's modulus. The change in resonant frequency through the glass transition was greatest for samples of intermediate fiber angle, demonstrating behavior similar to that of the longitudinal shear modulus.

Does Needle Rotation Improve Lesion Targeting?

PubMed Central

Badaan, Shadi; Petrisor, Doru; Kim, Chunwoo; Mozer, Pierre; Mazilu, Dumitru; Gruionu, Lucian; Patriciu, Alex; Cleary, Kevin; Stoianovici, Dan

2011-01-01

Background Image-guided robots are manipulators that operate based on medical images. Perhaps the most common class of image-guided robots are robots for needle interventions. Typically, these robots actively position and/or orient a needle guide, but needle insertion is still done by the physician. While this arrangement may have safety advantages and keep the physician in control of needle insertion, actuated needle drivers can incorporate other useful features. Methods We first present a new needle driver that can actively insert and rotate a needle. With this device we investigate the use of needle rotation in controlled in-vitro experiments performed with a specially developed revolving needle driver. Results These experiments show that needle rotation can improve targeting and may reduce errors by as much as 70%. Conclusion The new needle driver provides a unique kinematic architecture that enables insertion with a compact mechanism. Perhaps the most interesting conclusion of the study is that lesions of soft tissue organs may not be perfectly targeted with a needle without using special techniques, either manually or with a robotic device. The results of this study show that needle rotation may be an effective method of reducing targeting errors. PMID:21360796

Power Flow Angles for Slanted Finger Surface Acoustic Wave Filters on Langasite Substrate

NASA Astrophysics Data System (ADS)

Goto, Mikihiro; Yatsuda, Hiromi; Chiba, Takao

2007-07-01

Power flow angles (PFAs) on a langasite (LGS) substrate with Euler angles of (0{\\degree}, 138.5{\\degree}, \\psi), \\psi=25.7 to 27.7° are investigated for slanted finger interdigital transducer (SFIT) surface acoustic wave (SAW) filters by an electrical and optical methods. In the electrical method, several tilted SFIT SAW filters with different tilt angles for (0{\\degree}, 138.5{\\degree}, \\psi) LGS substrates were designed, and the frequency responses of the filters were measured. In the optical method, the PFAs were directly measured by optical probing for a parallel interdigital transducer (IDT) with wide propagation area on the substrate. As a result, a good correlation between electrical and optical measurements of the PFAs is obtained, but the calculated PFAs are slightly different from the measured PFAs. A good frequency response of a tilted 380 MHz SFIT SAW filter with an appropriate tilt angle corresponding to the PFA on the substrate is obtained even though the aperture is small.

Parametric Investigation on the Use of Lateral and Logitudinal Rotor Trim Flapping for Tiltrotor Noise Reduction

NASA Technical Reports Server (NTRS)

Malpica, Carlos

2017-01-01

This paper presents an acoustics parametric study of the effect of varying lateral and longitudinal rotor trim flapping angles (tip-path-plane tilt) on noise radiated by an isolated 26-ft diameter proprotor, similar to that of the AW609 tiltrotor, in edgewise flight. Three tip-path-plane angle of attack operating conditions of -9, 0 and 6 deg, at 80 knots, were investigated. Results showed that: 1) minimum noise was attained for the tip-path-plane angle of attack value of -9 deg, and 2) changing the cyclic trim state (i.e., controls) altered the airloads and produced noticeable changes to the low-frequency (LF) and blade-vortex interaction (BVI) radiated-noise magnitude and directionality. In particular, by trimming the rotor to a positive (inboard) lateral flapping angle of 4 deg, further reductions up to 3 dB in the low-frequency noise sound pressure level were attained without significantly impacting the BVI noise for longitudinal tip-path-plane angles of -9 and 6 deg.

EUS Needle Identification Comparison and Evaluation study (with videos).

PubMed

Tang, Shou-Jiang; Vilmann, Andreas S; Saftoiu, Adrian; Wang, Wanmei; Streba, Costin Teodor; Fink, Peter P; Griswold, Michael; Wu, Ruonan; Dietrich, Christoph F; Jenssen, Christian; Hocke, Michael; Kantowski, Marcus; Pohl, Jürgen; Fockens, Paul; Annema, Jouke T; van der Heijden, Erik H F M; Havre, Roald Flesland; Pham, Khanh Do-Cong; Kunda, Rastislav; Deprez, Pierre H; Mariana, Jinga; Vazquez-Sequeiros, Enrique; Larghi, Alberto; Buscarini, Elisabetta; Fusaroli, Pietro; Lahav, Maor; Puri, Rajesh; Garg, Pramod Kumar; Sharma, Malay; Maluf-Filho, Fauze; Sahai, Anand; Brugge, William R; Lee, Linda S; Aslanian, Harry R; Wang, Andrew Y; Shami, Vanessa M; Markowitz, Arnold; Siddiqui, Ali A; Mishra, Girish; Scheiman, James M; Isenberg, Gerard; Siddiqui, Uzma D; Shah, Raj J; Buxbaum, James; Watson, Rabindra R; Willingham, Field F; Bhutani, Manoop S; Levy, Michael J; Harris, Cynthia; Wallace, Michael B; Nolsøe, Christian Pállson; Lorentzen, Torben; Bang, Niels; Sørensen, Sten Mellerup; Gilja, Odd Helge; D'Onofrio, Mirko; Piscaglia, Fabio; Gritzmann, Norbert; Radzina, Maija; Sparchez, Zeno Adrian; Sidhu, Paul S; Freeman, Simon; McCowan, Timothy C; de Araujo, Cyrillo Rodrigues; Patel, Akash; Ali, Mohammad Adel; Campbell, Garth; Chen, Edward; Vilmann, Peter

2016-09-01

EUS-guided FNA or biopsy sampling is widely practiced. Optimal sonographic visualization of the needle is critical for image-guided interventions. Of the several commercially available needles, bench-top testing and direct comparison of these needles have not been done to reveal their inherent echogenicity. The aims are to provide bench-top data that can be used to guide clinical applications and to promote future device research and development. Descriptive bench-top testing and comparison of 8 commonly used EUS-FNA needles (all size 22 gauge): SonoTip Pro Control (Medi-Globe); Expect Slimline (Boston Scientific); EchoTip, EchoTip Ultra, EchoTip ProCore High Definition (Cook Medical); ClearView (Conmed); EZ Shot 2 (Olympus); and BNX (Beacon Endoscopic), and 2 new prototype needles, SonoCoat (Medi-Globe), coated by echogenic polymers made by Encapson. Blinded evaluation of standardized and unedited videos by 43 EUS endoscopists and 17 radiologists specialized in GI US examination who were unfamiliar with EUS needle devices. There was no significant difference in the ratings and rankings of these needles between endosonographers and radiologists. Overall, 1 prototype needle was rated as the best, ranking 10% to 40% higher than all other needles (P < .01). Among the commercially available needles, the EchoTip Ultra needle and the ClearView needle were top choices. The EZ Shot 2 needle was ranked statistically lower than other needles (30%-75% worse, P < .001). All FNA needles have their inherent and different echogenicities, and these differences are similarly recognized by EUS endoscopists and radiologists. Needles with polymeric coating from the entire shaft to the needle tip may offer better echogenicity. Copyright © 2016 American Society for Gastrointestinal Endoscopy. All rights reserved.

A comparison of 25 gauge Quincke spinal needle with 26 gauge Eldor spinal needle for the elective Caesarian sections: insertion characteristics and complications.

PubMed

Tabedar, S; Maharjan, S K; Shrestha, B R; Shrestha, B M

2003-01-01

The study was designed to compare the insertion characteristics and incidence of PDPH between 25 gauge Quincke needle and 26 gauge Eldor needle for spinal anaesthesia in elective c/s. 60 pregnant women (aged 19-35 yrs and weighing 58 -67 kg) undergoing elective caesarean section were randomized into group A (Quincke spinal needle group) or group B (Eldor spinal needle group). Spinal anaesthesia was performed with 2.9 ml 0.5% heavy bupivacaine using 25 gauge Quincke spinal needle in group A and 26 Gauge Eldor spinal needle in group B. Onset, time of first identification of backflow of CSF, number of attempts, level of sensory and motor blockade, failure of anaesthesia, inadequate anaesthesia and incidence of PDPH were recorded. Quincke spinal needle was found easy at insertion, first attempt was successful in 90% of cases, whereas Eldor spinal needle was successful at first attempt in only 60% of cases. Early identification of CSF was seen in Eldor spinal needle group in 3.5 seconds vs. 5.2 seconds in Quincke spinal needle group. Blood mixed CSF was seen in 8 Quincke spinal needle group vs. none in Eldor spinal needle group. Onset was similar between both groups i.e. in 6 minutes. Failure of anaesthesia was none in Eldor spinal needle group vs. 2 in quincke spinal needle group. Height of sensory block achieved was T4 level in 26 parturients,T6 in 1 ,T8 in 1 and no anaesthesia at all in another 2 parturient as compared to T4 level in 29 and T3 in 1 parturient in Eldor spinal needle group. The degree of motor block with the use of Bromage criteria showed a motor score of 1 or 2 in 26 parturients in Quincke spinal needle group vs. same in all cases in Eldor spinal needle group. The total incidence of PDPH was 8.3 % (5 out of 60 parturient) which occurred all in Quincke spinal needle group. 2 parturient who developed severe PDPH required epidural blood patch. 26 gauge Eldor spinal needle was found to be better than 25 gauge Quincke spinal needle for caesarian sections to decrease the incidence of PDPH, though not all insertion characteristics were in favour of the Eldor needle.

Bench-Top Feasibility Testing of a Novel Percutaneous Renal Access Technique: The Laser Direct Alignment Radiation Reduction Technique (DARRT).

PubMed

Khater, Nazih; Shen, Jim; Arenas, Javier; Keheila, Mohamed; Alsyouf, Muhannad; Martin, Jacob A; Lightfoot, Michelle A; Li, Roger; Olgin, Gaudencio; Smith, Jason C; Baldwin, D Duane

2016-11-01

Traditional techniques for obtaining percutaneous renal access utilize continuous fluoroscopy. In an attempt to minimize radiation exposure, we describe a novel laser direct alignment radiation reduction technique (DARRT) for percutaneous access and test it in a bench-top model. In this randomized-controlled bench-top study, 20 medical personnel obtained renal accesses using both the conventional bullseye technique and the laser DARRT. The primary endpoint was total fluoroscopy time. Secondary endpoints included insertion time, puncture attempts, course corrections, and subjective procedural difficulty. In the laser DARRT, fluoroscopy was used with the C-arm positioned with the laser beam at a 30° angle. The access needle and hub were aligned with the laser beam. Effective caliceal puncture was confirmed with fluoroscopy and direct vision. The Paired samples Wilcoxon signed rank test was used for statistical analysis with significance at p < 0.05. A total of 120 needle placements were recorded. Fluoroscopy time for needle access using the laser DARRT was significantly lower than the bullseye technique in all groups as follows: attendings (7.09 vs 18.51 seconds; p < 0.001), residents (6.55 vs 13.93 seconds; p = 0.001), and medical students (6.69 vs 20.22 seconds; p < 0.001). Students rated the laser DARRT easier to use (2.56 vs 4.89; p < 0.001). No difference was seen in total access time, puncture attempts, or course corrections between techniques. The laser DARRT reduced fluoroscopy time by 63%, compared with the conventional bullseye technique. The least experienced users found the laser DARRT significantly easier to learn. This novel technique is promising and merits additional testing in animal and human models.

Modeling, Production, and Testing of an Echogenic Needle for Ultrasound-Guided Nerve Blocks.

PubMed

Bigeleisen, Paul E; Hess, Aaron; Zhu, Richard; Krediet, Annelot

2016-06-01

We have designed, produced, and tested an echogenic needle based on a sawtooth pattern where the height of the tooth was 1.25 times the wavelength of the ultrasound transducer. A numeric solution to the time-independent wave equation (Helmholtz equation) was used to create a model of backscattering from a needle. A 21-gauge stainless steel prototype was manufactured and tested in a water bath. Backscattering from the needle was compared to theoretical predications from our model. Based on these results, an 18-gauge prototype needle was fabricated from stainless steel and tested in a pig cadaver. This needle was compared to a commercial 18-gauge echogenic needle (Pajunk Medical Systems, Tucker, GA) by measuring the brightness of the needle relative to the background of sonograms of a needle in a pig cadaver. The backscattering from the 21-gauge prototype needle reproduced the qualitative predictions of our model. At 30° and 45° of insonation, our prototype performed equivalently to the Pajunk needle. At 60°, our prototype was significantly brighter than the Pajunk needle (P = .017). In conclusion, we chose a model for the design of an echogenic needle and modeled it on the basis of a solution to the Helmholtz equation. A prototype needle was tested in a water bath and compared to the model prediction. After verification of our model, we designed an 18-gauge needle, which performed better than an existing echogenic needle (Pajunk) at 60° of insonation. Our needle will require further testing in human trials. © 2016 by the American Institute of Ultrasound in Medicine.

Comparison of sprotte and Quincke needles with respect to spinal fluid leakage using artificial spinal cord.

PubMed

Amaki, Yoshikiyo; Moriyama, Michihiko; Kuzuta, Toshimichi; Yabe, Keiko; Kaneko, Misato

1997-12-01

This research investigated whether the Sprotte needle causes less leakage of CSF than the Quincke needle in the artificial spinal cord. The changes in intradural pressure, extradural pressure, and leaked volume of CSF were evaluated following puncture with Sprotte and Quincke needles in the artificial spinal cord. The decrease in intradural pressure was 9.7±1.8 mm H 2 O with the Sprotte needle and 20.5±2.7 mm H 2 O with the Quincke needle (P<0.05). The volume of leakage of artificial CSF was 2.0±0.3 ml with the Sprotte needle and 3.3 ±0.3 ml with the Quincke needle (P<0.01). The extradural pressure increase was 166.1±8.2 mm H 2 O with the Sprotte needle and 186.8±13.2 mm H 2 O with the Quincke needle (P<0.05). The Sprotte needle produces less CSF leakage than the Quincke needle.

[Observation on therapeutic effect of three needling method on piriformis injury syndrome].

PubMed

Yang, Jun-xiong; Zhu, Xiao-yi

2008-03-01

To search for an effective needling method for treatment of piriformis injury syndrome. Eighty-two cases were randomly divided into a three needling group and a routine needling group, 41 cases in each group. The three needling group were treated by acupuncture at Huantiao (GB 30), Yanglingquan (GB 34) and Shenmai (BL 62), with needling shallow, middle and deep layers for Huantiao, Yanglingquan, and after acupuncture massage was given at the Foot-Taiyang Channel and the Foot-Shaoyang Channel on lumbosacral region and the affected foot. The routine needling group were treated by routine needling at Huantiao (GB 30), Juliao (GB 29), Chengfu (BL 36), Yanglingquan (GB 34), massage was given also. Their therapeutic effects were compared. The cured rate was 87.8% in the three needling group and 63.4% in the routine needling group, with a significant difference between the two groups (P < 0.05). The therapeutic effect of three needling method on piriformis injury syndrome is better than that of routine needling.

A major trade-off between structural and photosynthetic investments operative across plant and needle ages in three Mediterranean pines.

PubMed

Kuusk, Vivian; Niinemets, Ülo; Valladares, Fernando

2018-04-01

Pine (Pinus) species exhibit extensive variation in needle shape and size between juvenile (primary) and adult (secondary) needles (heteroblasty), but few studies have quantified the changes in needle morphological, anatomical and chemical traits upon juvenile-to-adult transition. Mediterranean pines keep juvenile needles longer than most other pines, implying that juvenile needles play a particularly significant role in seedling and sapling establishment in this environment. We studied needle anatomical, morphological and chemical characteristics in juvenile and different-aged adult needles in Mediterranean pines Pinus halepensis Mill., Pinus pinea L. and Pinus nigra J. F. Arnold subsp. salzmannii (Dunal) Franco hypothesizing that needle anatomical modifications upon juvenile-to-adult transition lead to a trade-off between investments in support and photosynthetic tissues, and that analogous changes occur with needle aging albeit to a lower degree. Compared with adult needles, juvenile needles of all species were narrower with 1.6- to 2.4-fold lower leaf dry mass per unit area, and had ~1.4-fold thinner cell walls, but needle nitrogen content per dry mass was similar among plant ages. Juvenile needles also had ~1.5-fold greater mesophyll volume fraction, ~3-fold greater chloroplast volume fraction and ~1.7-fold greater chloroplast exposed to mesophyll exposed surface area ratio, suggesting overall greater photosynthetic activity. Changes in needle traits were similar in aging adult needles, but the magnitude was generally less than the changes upon juvenile to adult transition. In adult needles, the fraction in support tissues scaled positively with known ranking of species tolerance of drought (P. halepensis > P. pinea > P. nigra). Across all species, and needle and plant ages, a negative correlation between volume fractions of mesophyll and structural tissues was observed, manifesting a trade-off between biomass investments in different needle functions. These results demonstrate that within the broad trade-off, juvenile and adult needle morphophysiotypes are separated by varying investments in support and photosynthetic functions. We suggest that the ecological advantage of the juvenile morphophysiotype is maximization of carbon gain of establishing saplings, while adult needle physiognomy enhances environmental stress tolerance of established plants.

The yield of adequate and conclusive fine-needle aspiration results in thyroid nodules is uniform across functional and goiter types.

PubMed

Liel, Y

1999-01-01

Relatively little is known about the cytological characteristics of hyperfunctioning (hot) thyroid nodules. Concern has been expressed that fine-needle aspiration (FNA) identifies hot nodules as follicular tumors or indeterminate, and as a consequence patients could be unnecessarily referred for surgery. Between 1979 and 1996, thyroid FNA was performed on 829 patients. Result of thyroid scan was available in 326; 69 (21%) patients had hot, and 257 (79%) had warm or cold thyroid nodules. Nodules in each of these major groups were divided into 2 subgroups: clinically solitary nodules and dominant nodules in multinodular goiters (MNG). The frequencies of adequate versus inadequate FNA samples, and of conclusive versus indeterminate FNA results were determined separately for each of the groups and subgroups. In addition, patients with hot nodules and overt hyperthyroidism were identified and evaluated separately. Bivariate analyses were performed for the frequency of adequate versus inadequate smears and conclusive versus indeterminate results between hot, toxic, and cold-warm nodules, and between solitary nodules and MNG. The frequency of adequate aspirations and conclusive results in the various groups and subgroups was found to be statistically indistinguishable. In conclusion, the yield of adequate samples and the rate of conclusive results of FNA in thyroid nodules is similar, irrespective of the functional state or of goiter presentation. Hot thyroid nodules do not seem to produce an increase in the rate of inadequate or indeterminate FNA results, and therefore, do not affect the overall performance of thyroid FNA.

Examination of surface conditions and other physical properties of commonly used stainless steel acupuncture needles.

PubMed

Xie, Yi Min; Xu, Shanqing; Zhang, Claire Shuiqing; Xue, Charlie Changli

2014-04-01

The present work examined the surface conditions and various other physical properties of sterilised single-use stainless steel acupuncture needles from two of the most popular brands widely used in many countries. Scanning electron microscope (SEM) images were taken for 10 randomly chosen needles from each brand. Further SEM images were taken after each of these needles underwent a standard manipulation with an acupuncture needling practice gel. A comparison of forces and torques during the needling process was also carried out. The SEM images revealed significant surface irregularities and inconsistencies at the needle tips, especially for needles from one of the two brands. Metallic lumps and small, loosely attached pieces of material were observed on the surfaces of some needles. Some of the lumps and pieces of material seen on the needle surfaces disappeared after the acupuncture manipulation. If these needles had been used on patients, the metallic lumps and small pieces of material could have been deposited in human tissues, which could have caused adverse events such as dermatitis. Malformed needle tips might also cause other adverse effects including bleeding, haematoma/bruising, or strong pain during needling. An off-centre needle tip could result in the needle altering its direction during insertion and consequently failing to reach the intended acupuncture point or damaging adjacent tissues. These findings highlight the need for improved quality control of acupuncture needles, with a view to further enhancing the safety and comfort of acupuncture users.

Characterization of granular flow dynamics from the generated high-frequency seismic signal: insights from laboratory experiments

NASA Astrophysics Data System (ADS)

Mangeney, A.; Farin, M.; de Rosny, J.; Toussaint, R.; Trinh, P. T.

2017-12-01

Landslides, rock avalanche and rockfalls represent a major natural hazard in steep environments. However, owing to the lack of visual observations, the dynamics of these gravitational events is still not well understood. A burning challenge is to deduce the landslide dynamics (flow potential energy, involved volume, particle size…) from the characteristics of the generated seismic signal (radiated seismic energy, maximum amplitude, frequencies,...). Laboratory experiments of granular columns collapse are conducted on an inclined plane. The seismic signal generated by the collapse is recorded by piezoelectric accelerometers sensitive in a wide frequency range (1 Hz - 56 kHz). The granular flow are constituted with steel beads of same diameter. We compare the dynamic parameters of the granular flows, deduced from the movie of the experiments, to the seismic parameters deduced from the measured seismic signals. The ratio of radiated seismic energy to potential energy lost is shown to slightly decrease with slope angle and is between 0.2% and 9%. It decreases as time, slope angle and flow volume increase and when the particle diameter decreases. These results explain the dispersion over several orders of magnitude of the seismic efficiency of natural landslides. We distinguish two successive phases of rise and decay in the time profiles if the amplitude of the seismic signal and of the mean frequency of the signal generated by the granular flows. The rise phase and the maximum are shown to be independent of the slope angle. The maximum seismic amplitude coincides with the maximum flow speed in the direction normal to the slope but not with the maximum downslope speed. We observe that the shape of the seismic envelope and frequencies as a function of time changes after a critical slope angle, between 10° and 15° with respect to the horizontal, with a decay phase lasting much longer as slope angle increases, due to a change in the flow regime, from a dense to a more agitated flow. In addition, we propose a semi-empirical scaling law to describe how the seismic energy radiated by a granular flow increases when the slope angle increases. The fit of this law with the seismic data allows us to retrieve the friction angle of the granular material, which is a crucial rheological parameter.

Investigation of an acoustical holography system for real-time imaging

NASA Astrophysics Data System (ADS)

Fecht, Barbara A.; Andre, Michael P.; Garlick, George F.; Shelby, Ronald L.; Shelby, Jerod O.; Lehman, Constance D.

1998-07-01

A new prototype imaging system based on ultrasound transmission through the object of interest -- acoustical holography -- was developed which incorporates significant improvements in acoustical and optical design. This system is being evaluated for potential clinical application in the musculoskeletal system, interventional radiology, pediatrics, monitoring of tumor ablation, vascular imaging and breast imaging. System limiting resolution was estimated using a line-pair target with decreasing line thickness and equal separation. For a swept frequency beam from 2.6 - 3.0 MHz, the minimum resolution was 0.5 lp/mm. Apatite crystals were suspended in castor oil to approximate breast microcalcifications. Crystals from 0.425 - 1.18 mm in diameter were well resolved in the acoustic zoom mode. Needle visibility was examined with both a 14-gauge biopsy needle and a 0.6 mm needle. The needle tip was clearly visible throughout the dynamic imaging sequence as it was slowly inserted into a RMI tissue-equivalent breast biopsy phantom. A selection of human images was acquired in several volunteers: a 25 year-old female volunteer with normal breast tissue, a lateral view of the elbow joint showing muscle fascia and tendon insertions, and the superficial vessels in the forearm. Real-time video images of these studies will be presented. In all of these studies, conventional sonography was used for comparison. These preliminary investigations with the new prototype acoustical holography system showed favorable results in comparison to state-of-the-art pulse-echo ultrasound and demonstrate it to be suitable for further clinical study. The new patient interfaces will facilitate orthopedic soft tissue evaluation, study of superficial vascular structures and potentially breast imaging.

A new rule for femoral nerve blocks.

PubMed

Schulz-Stübner, Sebastian; Henszel, Angela; Hata, J Steven

2005-01-01

Acupuncture points are described by use of a proportional system that is based on the width of the thumb at the level of the distal interphalangeal joint, defined as 1 CUN. Our study tested first the correlation between the CUN and weight and height in 500 Americans and second the hypothesis that the CUN system is superior to the conventional landmarks to localize the femoral nerve 1 or 2 cm lateral to the artery in a prospective, double-blinded, randomized study. Sixty-two patients were randomized to receive a femoral nerve block by a needle entry point either 1 CUN lateral, 1 cm lateral, or 2 cm lateral to the femoral artery at the level of the inguinal crease. The time from needle entry to injection of local anesthetic was measured by an investigator blind to the technique, who also counted the frequency of needle repositioning, graded the ease of the block and its success, and registered complications. Good correlation occurred between weight and CUN (r = 0.79) and height and CUN (r = 0.83), which indicates that the CUN of a normal person (predefined as 175 cm tall and 70 kg weight) is 18.7 +/- 1 mm. In the CUN group, the femoral block was achieved significantly faster (P < .01) with fewer attempts (P < .003). The success rate was the same and complications did not differ significantly between the groups. A needle insertion point 1 CUN lateral to the midpoint of the palpated femoral artery at the level of the inguinal crease makes femoral nerve blocks faster and easier compared with conventional landmark 1 cm to 2 cm lateral to the artery.

Association of serum prostate-specific antigen levels with the results of the prostate needle biopsy.

PubMed

Janbaziroudsari, Hamid; Mirzaei, Arezoo; Maleki, Nasrollah

2016-09-01

To investigate the relationship of serum prostate-specific antigen (PSA) levels with outcomes of prostate needle biopsy in men 50 or more years old. We measured serum PSA levels in 1472 healthy men 50 or more years old. Men who had serum PSA values 4.0ng/mL or higher underwent digital rectal examination. If there were either an elevated PSA level (≥4ng/mL) or abnormal digital rectal examination, a transrectal ultrasound-guided prostate biopsy was performed. The mean serum total PSA level was 13.73±11.44ng/mL, and the mean serum free PSA level was 4.99±0.97ng/mL. Of the 260 men who had serum total PSA levels of≥4ng/mL, 139 underwent biopsy. Of these 139 men, 45 (32.4%) had prostate cancer. Benign prostatic hyperplasia with or without prostatitis was diagnosed in 94 patients (67.6%). There was no significant correlation between age and histologic results of prostate needle biopsy (P-value=0.469). The serum free PSA showed no significant correlation with histologic results of prostate needle biopsy, whereas the serum total PSA level had a significant correlation in patients with adenocarcinoma compared with other diagnosis. The overall frequency of detection of prostate adenocarcinoma was 32.4%. This study revealed that no level of PSA was associated with a 100% positive predictive value and negative biopsy can occur virtually at any PSA level. There is a need to create awareness among the general population and health professionals for an early diagnosis of this common form of cancer. Copyright © 2016 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.

[Our experience using "Huber Plus" needles in our infusion center].

PubMed

Tazumi, Keiko; Kouji, Keiko; Matsumura, Natsuko; Nabetani, Yoshiko; Kondo, Motoi; Tomono, Kazunori; Mizuki, Masao

2008-01-01

We conducted a pilot trial to compare the operability and safety of two huber needles in the infusion center. In the present study, we used huber needles without the safety cover and one huber needle with the safety cover (Huber Plus(R)). Both huber needles were used nine times. The successful puncture rate of the first time puncture and the incidence of needle accidents with both huber needles were 100% and 0%, respectively. The evaluation of pain and uneasiness by VAS (Visual Analogue scale)revealed the superiority of the safety needle over the than non-safety needle(pain: 3.8 vs 2.6, uneasiness: 3.7 vs 0.5). To our knowledge, this is the first report of the safety of the huber needle in Japan. This system may be recommended in Japan to avoid needle stick injuries, patient pain and uneasiness.

Parity-time-symmetric teleportation

NASA Astrophysics Data System (ADS)

Ra'di, Y.; Sounas, D. L.; Alù, A.; Tretyakov, S. A.

2016-06-01

We show that electromagnetic plane waves can be fully "teleported" through thin, nearly fully reflective sheets, assisted by a pair of parity-time-symmetric lossy and active sheets in front and behind the screen. The proposed structure is able to almost perfectly absorb incident waves over a wide range of frequency and incidence angles, while waves having a specific frequency and incidence angle are replicated behind the structure in synchronization with the input signal. It is shown that the proposed structure can be designed to teleport waves at any desired frequency and incidence angle. Furthermore, we generalize the proposed concept to the case of teleportation of electromagnetic waves over electrically long distances, enabling full absorption at one surface and the synthesis of the same signal at another point located electrically far away from the first surface. The physical principle behind this selective teleportation is discussed, and similarities and differences with tunneling and cloaking concepts based on PT symmetry are investigated. From the application point of view, the proposed structure works as an extremely selective filter, both in frequency and spatial domains.

PIV Study on Flow around Leading-Edge Slat of 30P30N Airfoil

NASA Astrophysics Data System (ADS)

Ando, Ryosuke; Onishi, Yusaku; Sakakibara, Jun

2017-11-01

We measured flow velocity distribution around leading-edge slat using PIV. Simultaneously, noise measurement using microphone was also performed. A leading-edge slat and main wing model having a chord length of 160 mm was placed in the tunnel with free stream velocity of about 26m/s and chord Reynolds number of 2.8 x 105. Angle of attack was changed from 4 degrees to 10 degrees at two degree intervals. In this experiment, we investigated the relationship between the unsteady flow condition and the noise. At 4 degrees in the angle of attack, vortices shedding from the slat cusp were moved to the downstream. At 6 degrees or more, flow velocity distributions show that vortices were reattached on the slat lower surface and the flow in the slat cove recirculated. In FFT analysis of noise measurement, at 6 degrees in the angle of attack, there were some peaks on low frequency area and dominant peak on high frequency area was found. At 8 degrees or more, there were also some peaks on low frequency area. But dominant peak on high frequency area disappeared.

Acoustical imaging of high-frequency elastic responses of targets

NASA Astrophysics Data System (ADS)

Morse, Scot F.; Hefner, Brian T.; Marston, Philip L.

2002-05-01

Acoustical imaging was used to investigate high-frequency elastic responses to sound of two targets in water. The backscattering of broadband bipolar acoustic pulses by a truncated cylindrical shell was recorded over a wide range of tilt angles [S. F. Morse and P. L. Marston, ``Backscattering of transients by tilted truncated cylindrical shells: time-frequency identification of ray contributions from measurements,'' J. Acoust. Soc. Am. (in press)]. This data set was used to form synthetic aperture images of the target based on the data within different angular apertures. Over a range of viewing angles, the visibility of the cylinder's closest rear corner was significantly enhanced by the meridional flexural wave contribution to the backscattering. In another experiment, the time evolution of acoustic holographic images was used to explore the response of tilted elastic circular disks to tone bursts having frequencies of 250 and 300 kHz. For different tilt angles, specific responses that enhance the backscattering were identified from the time evolution of the images [B. T. Hefner and P. L. Marston, Acoust. Res. Lett. Online 2, 55-60 (2001)]. [Work supported by ONR.

Comparison of 25 G and 29 G Quincke spinal needles in paediatric day case surgery. A prospective randomized study of the puncture characteristics, success rate and postoperative complaints.

PubMed

Kokki, H; Hendolin, H

1996-01-01

A comparison of a 25 G with a 29 G Quincke needle was performed in paediatric day case surgery. Sixty healthy children aged 1 year to 13 years were randomly allocated to have spinal anaesthesia with either 25 G or 29 G Quincke needle without an introducer needle. There was a failure rate of 10% with the 29 G spinal needle compared with 0% with the 25 G needle. The time needed to perform dural puncture was shorter using 25 G than 29 G needle, 22 (+/- 31)(SD) vs 59 (+/- 63) s. The time taken for cerebrospinal fluid to appear at the needle hub was also longer, 4 (+/- 3) vs 8 (+/- 5) s. The number of puncture attempts was similar, 1.2 (+/- 0.6) vs 1.4 (+/- 0.8), with 25 G and 29 G needle. Low back pain, 5 vs1, and nonpositional headache, 2 vs 4, after 25 G and 29 G needles, respectively, were the most frequent postoperative complaints. Mild postdural puncture headache occurred in one eight year old male patient in the 25 G group. In conclusion, lumbar puncture without introducer needle was possible with both needles. The puncture characteristics favoured the 25 G needle. A shorter needle could partly alleviate the difficulties with the 29 G needle.

Comparison of fine-needle aspiration and core needle biopsy under ultrasonographic guidance for detecting malignancy and for the tissue-specific diagnosis of salivary gland tumors.

PubMed

Eom, H-J; Lee, J H; Ko, M-S; Choi, Y J; Yoon, R G; Cho, K J; Nam, S Y; Baek, J H

2015-06-01

Diagnostic test accuracy studies for ultrasonography-guided fine-needle aspiration and ultrasonography-guided core needle biopsy have shown inconclusive results due to their heterogenous study designs. Our aim was to compare the diagnostic accuracy of ultrasonography-guided fine-needle aspiration versus ultrasonography-guided core needle biopsy for detecting malignant tumors of the salivary gland and for the tissue-specific diagnosis of salivary gland tumors in a single tertiary hospital. This retrospective study was approved by our institutional review board and informed consent was waived. Four hundred twelve patients who underwent ultrasonography-guided fine-needle aspiration (n = 155) or ultrasonography-guided core needle biopsy (n = 257) with subsequent surgical confirmation or clinical follow-up were enrolled. We compared the diagnostic accuracy of ultrasonography-guided fine-needle aspiration and ultrasonography-guided core needle biopsy regarding malignant salivary gland tumors and the correct tissue-specific diagnosis of benign and malignant tumors. We also tested the difference between these procedures according to the operator's experience and lesion characteristics. The inconclusive rates of ultrasonography-guided fine-needle aspiration and ultrasonography-guided core needle biopsy were 19% and 4%, respectively (P < .001). The overall accuracy of ultrasonography-guided core needle biopsy for diagnosing malignant tumors was significantly higher than that of ultrasonography-guided fine-needle aspiration (P = .024). The correct tissue-specific diagnosis rates of ultrasonography-guided fine-needle aspiration and ultrasonography-guided core needle biopsy were 95% versus 97% for benign tumors (P = .648) and 67% versus 80% for malignant tumors (P = .310). Trainees showed significantly lower accuracy with ultrasonography-guided fine-needle aspiration than with ultrasonography-guided core needle biopsy for diagnosing malignant tumors (P = .021). There was no difference between the diagnostic accuracy of ultrasonography-guided fine-needle aspiration and ultrasonography-guided core needle biopsy according to the internal composition of the lesions. There were no complications requiring intervention or hospitalization in our patients. Ultrasonography-guided core needle biopsy is superior to ultrasonography-guided fine-needle aspiration in detecting and characterizing malignant tumors of the salivary gland and could emerge as the diagnostic method of choice for patients presenting with a salivary gland mass. © 2015 by American Journal of Neuroradiology.

A portable system with sample rate of 250 Hz for characterization of knee and hip angles in the sagittal plane during gait

PubMed Central

2014-01-01

Background Gait analysis and research have been developed to obtain characteristics of movement patterns of people while walking. However, traditional measuring systems present different drawbacks that reduce their use and application. Among those drawbacks one can find: high price, low sampling frequency and limiting number of steps to be analyzed. Traditional measuring gait systems carry out their measurement at frequencies oscillating between 60 to 100 Hz. It can be argued about the need of higher sampling rates for gait measurements. However small displacements of the knee or hip for example, cannot be seen with low frequencies required a more detailed sampling and higher frequency sampling. Bearing this in mind, in this paper is presented a 250 Hz system based on accelerometers for gait measurement, and the particularities of knee and hip angles during gait are highlighted. Methods The system was designed with a PCI data acquisition card instrumented with an FPGA to achieve a rate sample of 250 Hz. The accelerometers were placed in thighs and legs to calculate the joint angles of hip and knee in the sagittal plane. The angles were estimated using the acceleration polygon method without integrating the acceleration and without filters. Results The gait of thirty healthy people of Mexican phenotype was analyzed over a flat floor free of obstacles. The results showed the gait phases and particularities associated with the walking style and people's laterality; the movement patterns were similar in the thirty persons. Based on the results, the particularities as the maximum amplitude in the angles and the shape in the movement patterns were related to the anthropometry and people phenotype. Conclusions The sampling frequency was essential to record 340 samples in single gait cycle and so registering the gait cycle with its particularities. In this work were recorded an average of 8 to 10 gait cycles, and the results showed variation regarding works carried out in biomechanics laboratories; this variation was related to the method and reference frame used to obtain the joint angles and the accuracy of measurement system. PMID:24684720

A portable system with sample rate of 250 Hz for characterization of knee and hip angles in the sagittal plane during gait.

PubMed

Martínez-Solís, Fermín; Claudio-Sánchez, Abraham; Rodríguez-Lelis, José M; Vergara-Limon, Sergio; Olivares-Peregrino, Víctor; Vargas-Treviño, Marciano

2014-03-31

Gait analysis and research have been developed to obtain characteristics of movement patterns of people while walking. However, traditional measuring systems present different drawbacks that reduce their use and application. Among those drawbacks one can find: high price, low sampling frequency and limiting number of steps to be analyzed. Traditional measuring gait systems carry out their measurement at frequencies oscillating between 60 to 100 Hz. It can be argued about the need of higher sampling rates for gait measurements. However small displacements of the knee or hip for example, cannot be seen with low frequencies required a more detailed sampling and higher frequency sampling. Bearing this in mind, in this paper is presented a 250 Hz system based on accelerometers for gait measurement, and the particularities of knee and hip angles during gait are highlighted. The system was designed with a PCI data acquisition card instrumented with an FPGA to achieve a rate sample of 250 Hz. The accelerometers were placed in thighs and legs to calculate the joint angles of hip and knee in the sagittal plane. The angles were estimated using the acceleration polygon method without integrating the acceleration and without filters. The gait of thirty healthy people of Mexican phenotype was analyzed over a flat floor free of obstacles. The results showed the gait phases and particularities associated with the walking style and people's laterality; the movement patterns were similar in the thirty persons. Based on the results, the particularities as the maximum amplitude in the angles and the shape in the movement patterns were related to the anthropometry and people phenotype. The sampling frequency was essential to record 340 samples in single gait cycle and so registering the gait cycle with its particularities. In this work were recorded an average of 8 to 10 gait cycles, and the results showed variation regarding works carried out in biomechanics laboratories; this variation was related to the method and reference frame used to obtain the joint angles and the accuracy of measurement system.

Theory of the high-frequency chiral optical response of a p(x) + ip(y) superconductor.

PubMed

Yakovenko, Victor M

2007-02-23

The optical Hall conductivity and the polar Kerr angle are calculated as functions of temperature for a two-dimensional chiral p(x) + ip(y) superconductor, where the time-reversal symmetry is spontaneously broken. The theoretical estimate for the polar Kerr angle agrees by the order of magnitude with the recent experimental measurement in Sr2RuO4 by Xia et al. [Phys. Rev. Lett. 97, 167002 (2006)10.1103/PhysRevLett.97.167002]. The theory predicts that the Kerr angle is proportional to the square of the superconducting energy gap and is inversely proportional to the cube of frequency, which can be verified experimentally.

Carbon Fiber TOW Angle Determination Using Microwave Reflectometry

NASA Technical Reports Server (NTRS)

Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

2016-01-01

NASA's Advanced Composites Project is investigating technologies that increase automated remote inspection of aircraft composite structures. Therefore, microwave Frequency Domain Reflectometry (FDR) is being investigated as a method of enabling rapid remote inspection of angular orientation of the tow using microwave radiation. This work will present preliminary data demonstrating that frequency shifts in the reflection spectrum of a carbon fiber tow sample are indicative of the angle of the tow with respect to an interrogating antenna's linear polarized output.

Investigation and Assessment of Hardware for Guidance of Gliding Airdrop Systems

DTIC Science & Technology

1979-02-28

elevation angle that was necessary to provide free-space path losses for three terrain types at operating frequencies between (> and 100 Mil;.. There...airdrop package is able to achieve the target, its ele- vation angle will be sufficient to insure that free space path loss cal- culations are valid...Further calculations were made to determine the path loss between isotropic antennas at the frequencies most likely to be of interest, and at the

Enhanced ID Pit Sizing Using Multivariate Regression Algorithm

NASA Astrophysics Data System (ADS)

Krzywosz, Kenji

2007-03-01

EPRI is funding a program to enhance and improve the reliability of inside diameter (ID) pit sizing for balance-of plant heat exchangers, such as condensers and component cooling water heat exchangers. More traditional approaches to ID pit sizing involve the use of frequency-specific amplitude or phase angles. The enhanced multivariate regression algorithm for ID pit depth sizing incorporates three simultaneous input parameters of frequency, amplitude, and phase angle. A set of calibration data sets consisting of machined pits of various rounded and elongated shapes and depths was acquired in the frequency range of 100 kHz to 1 MHz for stainless steel tubing having nominal wall thickness of 0.028 inch. To add noise to the acquired data set, each test sample was rotated and test data acquired at 3, 6, 9, and 12 o'clock positions. The ID pit depths were estimated using a second order and fourth order regression functions by relying on normalized amplitude and phase angle information from multiple frequencies. Due to unique damage morphology associated with the microbiologically-influenced ID pits, it was necessary to modify the elongated calibration standard-based algorithms by relying on the algorithm developed solely from the destructive sectioning results. This paper presents the use of transformed multivariate regression algorithm to estimate ID pit depths and compare the results with the traditional univariate phase angle analysis. Both estimates were then compared with the destructive sectioning results.

Needle Steering in Biological Tissue using Ultrasound-based Online Curvature Estimation

PubMed Central

Moreira, Pedro; Patil, Sachin; Alterovitz, Ron; Misra, Sarthak

2014-01-01

Percutaneous needle insertions are commonly performed for diagnostic and therapeutic purposes. Accurate placement of the needle tip is important to the success of many needle procedures. The current needle steering systems depend on needle-tissue-specific data, such as maximum curvature, that is unavailable prior to an interventional procedure. In this paper, we present a novel three-dimensional adaptive steering method for flexible bevel-tipped needles that is capable of performing accurate tip placement without previous knowledge about needle curvature. The method steers the needle by integrating duty-cycled needle steering, online curvature estimation, ultrasound-based needle tracking, and sampling-based motion planning. The needle curvature estimation is performed online and used to adapt the path and duty cycling. We evaluated the method using experiments in a homogenous gelatin phantom, a two-layer gelatin phantom, and a biological tissue phantom composed of a gelatin layer and in vitro chicken tissue. In all experiments, virtual obstacles and targets move in order to represent the disturbances that might occur due to tissue deformation and physiological processes. The average targeting error using our new adaptive method is 40% lower than using the conventional non-adaptive duty-cycled needle steering method. PMID:26229729

A systematic approach to fabricate high aspect ratio silicon micro-needles for transdermal drug delivery

NASA Astrophysics Data System (ADS)

Ng, H. B.; Shearwood, C.

2007-12-01

The successful development of micro-needles can help transport drugs and vaccines both effectively and painlessly across the skin. However, not all micro-needles are strong enough to withstand the insertion forces and viscoelasticity of the skin. The work here focuses on the micro-fabrication of high aspect ratio needles with careful control of needle-profile using dry etching technologies. Silicon micro-needles, 150μm in length with base-diameters ranging from 90 to 240μm have been investigated in this study. A novel, multiple-sacrificial approach has been demonstrated as suited to the fabrication of long micro-needle bodies with positive profiles. The parameters that control the isotropic etching are adjusted to control the ratio of the needle-base diameter to needle length. By careful control of geometry, the needle profile can be engineered to give a suitable tip size for penetration, as well as a broad needle base to facilitate the creation of either single or multiple-through holes. This approach allows the mechanical properties of the otherwise brittle needles to be optimized. Finite element analysis indicates that the micro-needles will fracture prematurely due to buckling, with forces ranging from 10 to 30mN.

Bow shock formation in a complex plasma.

PubMed

Saitou, Y; Nakamura, Y; Kamimura, T; Ishihara, O

2012-02-10

A bow shock is observed in a two-dimensional supersonic flow of charged microparticles in a complex plasma. A thin conducting needle is used to make a potential barrier as an obstacle for the particle flow in the complex plasma. The flow is generated and the flow velocity is controlled by changing a tilt angle of the device under the gravitational force. A void, microparticle-free region, is formed around the potential barrier surrounding the obstacle. The flow is bent around the leading edge of the void and forms an arcuate structure when the flow is supersonic. The structure is characterized by the bow shock as confirmed by a polytropic hydrodynamic theory as well as numerical simulation.

The leaf-shape effect on electromagnetic scattering from vegetated media

NASA Technical Reports Server (NTRS)

Karam, M. A.; Fung, A. K.; Blanchard, A. J.; Shen, G. X.

1988-01-01

Using the generalized Rayleigh Gans approximation along with the radiative transfer method, a bistatic backscattering model for a layer of randomly oriented, elliptic-shaped leaves is formulated. Following a similar procedure the bistatic scattering model for a layer of needle-shaped leaves is also developed to simulate coniferous vegetation. The differences between the scattering characteristics of the deciduous and coniferous leaves are illustrated numerically for different orientation and incidence angles. It is found that both like and cross polarizations are needed to differentiate the difference in scattering due to the shapes of the scatterers. The calculated backscattering coefficients are compared with measured values from artificial canopies with circular-shaped leaves.

Needle bar for warp knitting machines

DOEpatents

Hagel, Adolf; Thumling, Manfred

1979-01-01

Needle bar for warp knitting machines with a number of needles individually set into slits of the bar and having shafts cranked to such an extent that the head section of each needle is in alignment with the shaft section accommodated by the slit. Slackening of the needles will thus not influence the needle spacing.

Robot-Assisted Needle Steering

PubMed Central

Reed, Kyle B.; Majewicz, Ann; Kallem, Vinutha; Alterovitz, Ron; Goldberg, Ken; Cowan, Noah J.; Okamura, Allison M.

2012-01-01

Needle insertion is a critical aspect of many medical treatments, diagnostic methods, and scientific studies, and is considered to be one of the simplest and most minimally invasive medical procedures. Robot-assisted needle steering has the potential to improve the effectiveness of existing medical procedures and enable new ones by allowing increased accuracy through more dexterous control of the needle tip path and acquisition of targets not accessible by straight-line trajectories. In this article, we describe a robot-assisted needle steering system that uses three integrated controllers: a motion planner concerned with guiding the needle around obstacles to a target in a desired plane, a planar controller that maintains the needle in the desired plane, and a torsion compensator that controls the needle tip orientation about the axis of the needle shaft. Experimental results from steering an asymmetric-tip needle in artificial tissue demonstrate the effectiveness of the system and its sensitivity to various environmental and control parameters. In addition, we show an example of needle steering in ex vivo biological tissue to accomplish a clinically relevant task, and highlight challenges of practical needle steering implementation. PMID:23028210

Radar response to vegetation. II - 8-18 GHz band

NASA Technical Reports Server (NTRS)

Ulaby, F. T.; Bush, T. F.; Batlivala, P. P.

1975-01-01

The results of experimental studies on the backscattering properties of corn, milo, soybeans, and alfalfa are presented. The measurements were made during the summer of 1973 over the 8-18 GHz frequency band. The data indicate that soil moisture estimation is best accomplished at incidence angles near nadir with lower frequencies while crop discrimination is best accomplished using two frequencies at incidence angles ranging from 30 deg to 65 deg. It is also shown that temporal plant morphology variations can cause extreme variations in the values of the scattering coefficients. These morphological changes can be caused by growth, heavy rain, and in the case of alfalfa, harvesting.

SU-D-213AB-06: Surface Texture and Insertion Speed Effect on Needle Friction.

PubMed

Abdullah, A; Golecki, C; Barnett, A; Moore, J

2012-06-01

High frictional forces between the needle surface and tissue cause tissue deflection which hinders accurate needle placement for procedures such as brachytherapy and needle biopsy. Accurate needle placement isimportant to maximize procedure efficacy. This work investigates how needle surface roughness and insertion speed affect the frictional forcebetween a needle and tissue. A friction experiment was conducted to measure the force of friction between bovine liver and three 11 gauge needles having Ra surface roughness of 3.43, 1.33, and 0.2 μm. Each of the three needles were mounted on a linear slide and were advanced and retracted through bovine liver at speeds of 50, 100, 150, and 200 mm/s for a total of 12 trials. In each trial the needle was advanced and retracted in 10 cycles producing a steady state insertion force and a steady state retraction force for each cycle. A force sensor connecting the needle to the linear slide recorded the resistance force of the needle sliding through the liver. The liver was mounted in a box with a pneumatic cylinder which compressed the liver sample by 11.65 kPa. The roughest needle (Ra = 3.43 μm) on average produced 68, 73, 74, and 73% lower friction force than the smoothest needle (Ra = 0.2 μm) for the speeds of 50, 100, 150, and 200mm/s, respectively. The second roughest needle (Ra = 1.33 μm) on average produced 25, 45, 60 and 64% lower friction force than the smoothest needle (Ra = 0.2 μm) for the speeds of 50, 100, 150, and 200 mm/s, respectively. Rougher needle surface texture and higher insertion speed reduced frictional forces between the tissue and the needle. Future studies will examine how frictional forces can be modeled and predicted given surface texture and insertion speed. © 2012 American Association of Physicists in Medicine.

Impact of Ion Bombardment on the Structure and Magnetic Properties of Fe78Si13B9 Amorphous Alloy

NASA Astrophysics Data System (ADS)

Wu, Yingwei; Peng, Kun

2018-06-01

Amorphous Fe78Si13B9 alloy ribbons were bombarded by ion beams with different incident angles ( θ ). The evolution of the microstructure and magnetic properties of ribbons caused by ion beam bombardment was investigated by x-ray diffraction, transmission electron microscope and vibrating sample magnetometer analysis. Low-incident-angle bombardment led to atomic migration in the short range, and high-incident-angle bombardment resulted in the crystallization of amorphous alloys. Ion bombardment induces magnetic anisotropy and affects magnetic properties. The effective magnetic anisotropy was determined by applying the law of approach to saturation, and it increased with the increase of the ion bombardment angle. The introduction of effective magnetic anisotropy will reduce the permeability and increase the relaxation frequency. Excellent high-frequency magnetic properties can be obtained by selecting suitable ion bombardment parameters.

Unsteady aerodynamics of an oscillating cascade in a compressible flow field

NASA Technical Reports Server (NTRS)

Buffum, Daniel H.; Boldman, Donald R.; Fleeter, Sanford

1987-01-01

Fundamental experiments were performed in the NASA Lewis Transonic Oscillating Cascade Facility to investigate and quantify the unsteady aerodynamics of a cascade of biconvex airfoils executing torsion-mode oscillations at realistic reduced frequencies. Flush-mounted, high-response miniature pressure transducers were used to measure the unsteady airfoil surface pressures. The pressures were measured for three interblade phase angles at two inlet Mach numbers, 0.65 and 0.80, and two incidence angles, 0 and 7 deg. The time-variant pressures were analyzed by means of discrete Fourier transform techniques, and these unique data were then compared with predictions from a linearized unsteady cascade model. The experimental results indicate that the interblade phase angle had a major effect on the chordwise distributions of the airfoil surface unsteady pressure, and that reduced frequency, incidence angle, and Mach number had a somewhat less significant effect.

Low-speed wind tunnel tests of a 50.8-centimeter (20-in.) 1.15-pressure-ratio fan engine model

NASA Technical Reports Server (NTRS)

Wesoky, H. L.; Abbott, J. M.; Albers, J. A.; Dietrich, D. A.

1974-01-01

At a typical STOL aircraft takeoff and landing velocity, wind tunnel aerodynamic and acoustic measurements demonstrated that an inlet lip-area contraction ratio of 1.35 was superior to a ratio of 1.26 at high incidence angles. A 17 percent reduction in net thrust and an increase of 9 decibels in sound pressure level at the blade passing frequency resulted from inlet flow separation at an incidence angle of 50 deg with the 1.26-contraction-ratio inlet. Reverse-thrust forces obtained with blade rotation through the feathered angle were 1.8 times larger than with blade rotation through the flat angle. Reverse-thrust force was reduced from 30 to 50 percent and sound pressure level increased from 3 to 7 decibels at the blade passing frequency between the wind-tunnel-off condition and a typical STOL aircraft landing velocity.

Is the pencil point spinal needle a better choice in younger patients? A comparison of 24G Sprotte with 27G Quincke needles in an unselected group of general surgical patients below 46 years of age.

PubMed

Brattebø, G; Wisborg, T; Rodt, S A; Røste, I

1995-05-01

Reports have indicated that there are less postoperative complaints after the use of pencil pointed spinal needles. We compared a 24G Sprotte needle with a 27G Quincke needle in a randomised study of 200 healthy patients (49% females), aged 15-46 years. Four patients (2%) reported postdural puncture headache, three with the 24G Sprotte needle and one with the 27G Quincke needle. Thirteen patients (7%) suffered with nonspecific headache, with no significant difference between the two groups. Of the 57 (29%) who reported backpain, a significantly higher proportion had received spinal anaesthesia with the Sprotte needle (OR = 2.06). There was a significantly higher incidence of insufficient blocks after dural puncture with the Sprotte needle. Ease of needle insertion and number of puncture attempts was the same for both needle types.

[Design and application of silver needle-knife].

PubMed

Sun, Guodong; Shi, Bin; Zhang, Benwu; Xu, Haidong

2015-04-01

A silver needle-knife which has the dual function of silver needle and needle-knife is designed. The main components of this silver needle-knife are approximately 50% silver and approximately 50% nichrome. The silver needle-knife is composed of five parts, including needle-knife tail, spiral handle; steering handle, needle-knife body and needle-knife edge. It converges the advantages of needle-knife and silver needle, which can cut loose of diseased tissue and peel adhesion of lesions, but also be heated with moxa cone and thermal therapeutic instrument, and connect with electroacupuncture apparatus. It has the function of warming channel and removing coldness, dispelling wind and eliminating dampness, resolving spasm and relieving pain, dredging the channel and so on. Due to the spiral handle and the steering handle, the operation is easier, which reduces the blindness of cutting and increase the safety. It is mainly used for soft tissue injury, rheumatism and rheumatoid arthritis, as well as degenerative diseases of spine and joint, and it has obvious efficacy on some internal medical diseases.

Teleoperated master-slave needle insertion.

PubMed

Abolhassani, Niki; Patel, Rajni V

2009-12-01

Accuracy of needle tip placement and needle tracking in soft tissue are of particular importance in many medical procedures. In recent years, developing autonomous and teleoperated systems for needle insertion has become an active area of research. In this study, needle insertion was performed using a master-slave set-up with multi-degrees of freedom. The effect of force feedback on the accuracy of needle insertion was investigated. In addition, this study compared autonomous, teleoperated and semi-autonomous needle insertion. The results of this study show that incorporation of force feedback can improve teleoperated needle insertion. However, autonomous and semi-autonomous needle insertions, which use feedback from a deflection model, provide significantly better performance. Development of a haptic master-slave needle insertion system, which is capable of performing some autonomous tasks based on feedback from tissue deformation and needle deflection models, can improve the performance of autonomous robotics-based insertions as well as non-autonomous teleoperated manual insertions. Copyright (c) 2009 John Wiley & Sons, Ltd.

Enhancement of Dual-Band Reflection-Mode Circular Polarizers Using Dual-Layer Rectangular Frequency Selective Surfaces

NASA Astrophysics Data System (ADS)

Fartookzadeh, M.; Mohseni Armaki, S. H.

2016-10-01

A new kind of dual-band reflection-mode circular polarizers (RMCPs) is introduced with wide bandwidth and wide-view at the operating frequencies. The proposed RMCPs are based on dual-layer rectangular patches on both sides of a substrate, separated by a foam or air layer from the ground plane. Required TE susceptance of the first layer patches to produce circular polarization is calculated using the equivalent transmission line model. Dimensions of the RMCP are obtained using parametrical study for the two frequency bands, 1.9-2.3 GHz and 7.9-8.3 GHz. In addition, it is indicated that the accepted view angle and bandwidth of the proposed dual-layer RMCP are improved compared with the single layer RMCP, significantly. Moreover, a tradeoff is observed for the dual-layer RMCP on the bandwidths of X band and S band that can be controlled by propagation angle of the incident wave. The proposed RMCP has 30.5 % and 33.7 % bandwidths for less than 3 dB axial ratio with incident angles {\\theta}max=50{\\deg} and {\\theta}min=35{\\deg}. Finally, simulation results are met by the measurement for three angles of the incident wave.

A 2D mechanical-magneto-thermal model for direction-dependent magnetoelectric effect in laminates

NASA Astrophysics Data System (ADS)

Zhang, Shunzu; Yao, Hong; Gao, Yuanwen

2017-04-01

A two dimensional (2D) mechanical-magneto-thermal model of direction-dependent magnetoelectric (ME) effect in Terfenol-D/PZT/Terfenol-D laminated composites is established. The expressions of ME coefficient at low and resonance frequencies are derived by the average field method, respectively. The prediction of theoretical model presents a good agreement with the experimental data. The combined effect of orientation-dependent stress and magnetic fields, as well as operating temperature on ME coefficient is discussed. It is shown that ME effect presents a significantly nonlinear change with the increasing pre-stress under different loading angles. There exists an optimal angle and value of pre-stress corresponding to the best ME effect, improving the angle of pre-stress can get more prominent ME coupling than in x axis state. Note that an optimal angle of magnetic field gradually increases with the rise of pre-stress, which can further lead to the enhancement of ME coefficient. Meanwhile, reducing the operating temperature can enhance ME coefficient. Furthermore, resonance frequency, affected by pre-stress, magnetic field and temperature via " ΔE effect", can enhance ME coefficient about 100 times than that at low frequency.

Refraction and scattering of sound by a shear layer

NASA Technical Reports Server (NTRS)

Schlinker, R. H.; Amiet, R. K.

1980-01-01

The angle and amplitude changes for acoustic waves refracted by a circular open jet shear layer were determined. The generalized refraction theory was assessed experimentally for on axis and off axis acoustic source locations as source frequency varied from 1 kHz to 10 kHz and free stream Mach number varied from 0.1 to 0.4. Angle and amplitude changes across the shear layer show good agreement with theory. Experiments confirm that the refraction theory is independent of shear layer thickness, acoustic source frequency, and source type. A generalized theory is, thus, available for correcting far field noise data acquired in open jet test facilities. The effect of discrete tone scattering by the open jet turbulent shear layer was also studied. Scattering effects were investigated over the same Mach number range as frequency varied from 5 kHz to 15 kHz. Attenuation of discrete tone amplitude and tone broadening were measured as a function of acoustic source position and radiation angle. Scattering was found to be stronger at angles close to the open jet axis than at 90 deg, and becomes stronger as the acoustic source position shifts downstream. A scattering analysis provided an estimate of the onset of discrete tone scattering.

Effect of Human Movement on Galvanic Intra-Body Communication during Single Gait Cycle

NASA Astrophysics Data System (ADS)

Ibrahim, I. W.; Razak, A. H. A.; Ahmad, A.; Salleh, M. K. M.

2015-11-01

Intra-body communication (IBC) is a communication system that uses human body as a signal transmission medium. From previous research, two coupling methods of IBC were concluded which are capacitive coupling and galvanic coupling. This paper investigates the effect of human movement on IBC using the galvanic coupling method. Because the human movement is control by the limb joint, the knee flexion angle during gait cycle was used to examine the influence of human movement on galvanic coupling IBC. The gait cycle is a cycle of people walking that start from one foot touch the ground till that foot touch the ground again. Frequency range from 300 kHz to 200MHz was swept in order to investigate the signal transmission loss and the result was focused on operating frequency 70MHz to 90MHz. Results show that the transmission loss varies when the knee flexion angle increased. The highest loss of signal at frequency range between 70MHz to 90 MHz was 69dB when the knee flexion angle is 50° and the minimum loss was 51dB during the flexion angle is 5°.

[Academic origin of round magnetic needle and standardization operation].

PubMed

Cheng, Yan-Ting; Zhang, Tian-Sheng; Meng, Li-Qiang; Shi, Rui-Qi; Ji, Lai-Xi

2014-07-01

The origin and development of round magnetic needle was explored, and the structure of round magnetic needle was introduced in detail, including the handle, the body and the tip of the needle. The clinical opera tion of round magnetic needle were standardized from the aspects of the methods of holding needle, manipulation skill, tapping position, strength of manipulation, application scope and matters needing attention, which laid foundation for the popularization and application of round magnetic needle.

40 MHz high-frequency ultrafast ultrasound imaging.

PubMed

Huang, Chih-Chung; Chen, Pei-Yu; Peng, Po-Hsun; Lee, Po-Yang

2017-06-01

Ultrafast high-frame-rate ultrasound imaging based on coherent-plane-wave compounding has been developed for many biomedical applications. Most coherent-plane-wave compounding systems typically operate at 3-15 MHz, and the image resolution for this frequency range is not sufficient for visualizing microstructure tissues. Therefore, the purpose of this study was to implement a high-frequency ultrafast ultrasound imaging operating at 40 MHz. The plane-wave compounding imaging and conventional multifocus B-mode imaging were performed using the Field II toolbox of MATLAB in simulation study. In experiments, plane-wave compounding images were obtained from a 256 channel ultrasound research platform with a 40 MHz array transducer. All images were produced by point-spread functions and cyst phantoms. The in vivo experiment was performed from zebrafish. Since high-frequency ultrasound exhibits a lower penetration, chirp excitation was applied to increase the imaging depth in simulation. The simulation results showed that a lateral resolution of up to 66.93 μm and a contrast of up to 56.41 dB were achieved when using 75-angles plane waves in compounding imaging. The experimental results showed that a lateral resolution of up to 74.83 μm and a contrast of up to 44.62 dB were achieved when using 75-angles plane waves in compounding imaging. The dead zone and compounding noise are about 1.2 mm and 2.0 mm in depth for experimental compounding imaging, respectively. The structure of zebrafish heart was observed clearly using plane-wave compounding imaging. The use of fewer than 23 angles for compounding allowed a frame rate higher than 1000 frames per second. However, the compounding imaging exhibits a similar lateral resolution of about 72 μm as the angle of plane wave is higher than 10 angles. This study shows the highest operational frequency for ultrafast high-frame-rate ultrasound imaging. © 2017 American Association of Physicists in Medicine.

Motion estimation using point cluster method and Kalman filter.

PubMed

Senesh, M; Wolf, A

2009-05-01

The most frequently used method in a three dimensional human gait analysis involves placing markers on the skin of the analyzed segment. This introduces a significant artifact, which strongly influences the bone position and orientation and joint kinematic estimates. In this study, we tested and evaluated the effect of adding a Kalman filter procedure to the previously reported point cluster technique (PCT) in the estimation of a rigid body motion. We demonstrated the procedures by motion analysis of a compound planar pendulum from indirect opto-electronic measurements of markers attached to an elastic appendage that is restrained to slide along the rigid body long axis. The elastic frequency is close to the pendulum frequency, as in the biomechanical problem, where the soft tissue frequency content is similar to the actual movement of the bones. Comparison of the real pendulum angle to that obtained by several estimation procedures--PCT, Kalman filter followed by PCT, and low pass filter followed by PCT--enables evaluation of the accuracy of the procedures. When comparing the maximal amplitude, no effect was noted by adding the Kalman filter; however, a closer look at the signal revealed that the estimated angle based only on the PCT method was very noisy with fluctuation, while the estimated angle based on the Kalman filter followed by the PCT was a smooth signal. It was also noted that the instantaneous frequencies obtained from the estimated angle based on the PCT method is more dispersed than those obtained from the estimated angle based on Kalman filter followed by the PCT method. Addition of a Kalman filter to the PCT method in the estimation procedure of rigid body motion results in a smoother signal that better represents the real motion, with less signal distortion than when using a digital low pass filter. Furthermore, it can be concluded that adding a Kalman filter to the PCT procedure substantially reduces the dispersion of the maximal and minimal instantaneous frequencies.

Setting the magic angle for fast magic-angle spinning probes.

PubMed

Penzel, Susanne; Smith, Albert A; Ernst, Matthias; Meier, Beat H

2018-06-15

Fast magic-angle spinning, coupled with 1 H detection is a powerful method to improve spectral resolution and signal to noise in solid-state NMR spectra. Commercial probes now provide spinning frequencies in excess of 100 kHz. Then, one has sufficient resolution in the 1 H dimension to directly detect protons, which have a gyromagnetic ratio approximately four times larger than 13 C spins. However, the gains in sensitivity can quickly be lost if the rotation angle is not set precisely. The most common method of magic-angle calibration is to optimize the number of rotary echoes, or sideband intensity, observed on a sample of KBr. However, this typically uses relatively low spinning frequencies, where the spinning of fast-MAS probes is often unstable, and detection on the 13 C channel, for which fast-MAS probes are typically not optimized. Therefore, we compare the KBr-based optimization of the magic angle with two alternative approaches: optimization of the splitting observed in 13 C-labeled glycine-ethylester on the carbonyl due to the Cα-C' J-coupling, or optimization of the H-N J-coupling spin echo in the protein sample itself. The latter method has the particular advantage that no separate sample is necessary for the magic-angle optimization. Copyright © 2018. Published by Elsevier Inc.

Leg stiffness and stride frequency in human running.

PubMed

Farley, C T; González, O

1996-02-01

When humans and other mammals run, the body's complex system of muscle, tendon and ligament springs behaves like a single linear spring ('leg spring'). A simple spring-mass model, consisting of a single linear leg spring and a mass equivalent to the animal's mass, has been shown to describe the mechanics of running remarkably well. Force platform measurements from running animals, including humans, have shown that the stiffness of the leg spring remains nearly the same at all speeds and that the spring-mass system is adjusted for higher speeds by increasing the angle swept by the leg spring. The goal of the present study is to determine the relative importance of changes to the leg spring stiffness and the angle swept by the leg spring when humans alter their stride frequency at a given running speed. Human subjects ran on treadmill-mounted force platform at 2.5ms-1 while using a range of stride frequencies from 26% below to 36% above the preferred stride frequency. Force platform measurements revealed that the stiffness of the leg spring increased by 2.3-fold from 7.0 to 16.3 kNm-1 between the lowest and highest stride frequencies. The angle swept by the leg spring decreased at higher stride frequencies, partially offsetting the effect of the increased leg spring stiffness on the mechanical behavior of the spring-mass system. We conclude that the most important adjustment to the body's spring system to accommodate higher stride frequencies is that leg spring becomes stiffer.

Histological observation for needle-tissue interactions.

PubMed

Nakagawa, Yoshiyuki; Koseki, Yoshihiko

2013-01-01

We histologically investigated tissue fractures and deformations caused by ex vivo needle insertions. The tissue was formalin-fixed while the needle remained in the tissue. Following removal of the needle, the tissue was microtomed, stained, and observed microscopically. This method enabled observations of cellular and tissular conditions where deformations caused by needle insertions were approximately preserved. For this study, our novel method presents preliminary findings related with tissue fractures and the orientation of needle blade relative to muscle fibers. When the needle blade was perpendicular to the muscle fiber, transfiber fractures and relatively large longitudinal deformations occurred. When the needle blade was parallel to the muscle fiber, interfiber fractures and relatively small longitudinal deformations occurred. This made a significant difference in the resistance force of the needle insertions.

Development of 3D ultrasound needle guidance for high-dose-rate interstitial brachytherapy of gynaecological cancers

NASA Astrophysics Data System (ADS)

Rodgers, J.; Tessier, D.; D'Souza, D.; Leung, E.; Hajdok, G.; Fenster, A.

2016-04-01

High-dose-rate (HDR) interstitial brachytherapy is often included in standard-of-care for gynaecological cancers. Needles are currently inserted through a perineal template without any standard real-time imaging modality to assist needle guidance, causing physicians to rely on pre-operative imaging, clinical examination, and experience. While two-dimensional (2D) ultrasound (US) is sometimes used for real-time guidance, visualization of needle placement and depth is difficult and subject to variability and inaccuracy in 2D images. The close proximity to critical organs, in particular the rectum and bladder, can lead to serious complications. We have developed a three-dimensional (3D) transrectal US system and are investigating its use for intra-operative visualization of needle positions used in HDR gynaecological brachytherapy. As a proof-of-concept, four patients were imaged with post-insertion 3D US and x-ray CT. Using software developed in our laboratory, manual rigid registration of the two modalities was performed based on the perineal template's vaginal cylinder. The needle tip and a second point along the needle path were identified for each needle visible in US. The difference between modalities in the needle trajectory and needle tip position was calculated for each identified needle. For the 60 needles placed, the mean trajectory difference was 3.23 +/- 1.65° across the 53 visible needle paths and the mean difference in needle tip position was 3.89 +/- 1.92 mm across the 48 visible needles tips. Based on the preliminary results, 3D transrectal US shows potential for the development of a 3D US-based needle guidance system for interstitial gynaecological brachytherapy.

Detecting stages of needle penetration into tissues through force estimation at needle tip using fiber Bragg grating sensors

NASA Astrophysics Data System (ADS)

Kumar, Saurabh; Shrikanth, Venkoba; Amrutur, Bharadwaj; Asokan, Sundarrajan; Bobji, Musuvathi S.

2016-12-01

Several medical procedures involve the use of needles. The advent of robotic and robot assisted procedures requires dynamic estimation of the needle tip location during insertion for use in both assistive systems as well as for automatic control. Most prior studies have focused on the maneuvering of solid flexible needles using external force measurements at the base of the needle holder. However, hollow needles are used in several procedures and measurements of forces in proximity of such needles can eliminate the need for estimating frictional forces that have high variations. These measurements are also significant for endoscopic procedures in which measurement of forces at the needle holder base is difficult. Fiber Bragg grating sensors, due to their small size, inert nature, and multiplexing capability, provide a good option for this purpose. Force measurements have been undertaken during needle insertion into tissue mimicking phantoms made of polydimethylsiloxane as well as chicken tissue using an 18-G needle instrumented with FBG sensors. The results obtained show that it is possible to estimate the different stages of needle penetration including partial rupture, which is significant for procedures in which precise estimation of needle tip position inside the organ or tissue is required.

Was the Big Bang hot?

NASA Technical Reports Server (NTRS)

Wright, E. L.

1983-01-01

Techniques for verifying the spectrum defined by Woody and Richards (WR, 1981), which serves as a base for dust-distorted models of the 3 K background, are discussed. WR detected a sharp deviation from the Planck curve in the 3 K background. The absolute intensity of the background may be determined by the frequency dependence of the dipole anisotropy of the background or the frequency dependence effect in galactic clusters. Both methods involve the Doppler shift; analytical formulae are defined for characterization of the dipole anisotropy. The measurement of the 30-300 GHz spectra of cold galactic dust may reveal the presence of significant amounts of needle-shaped grains, which would in turn support a theory of a cold Big Bang.

Frequency-Tracking CW Doppler Radar Solving Small-Angle Approximation and Null Point Issues in Non-Contact Vital Signs Monitoring.

PubMed

Mercuri, Marco; Liu, Yao-Hong; Lorato, Ilde; Torfs, Tom; Bourdoux, Andre; Van Hoof, Chris

2017-06-01

A Doppler radar operating as a Phase-Locked-Loop (PLL) in frequency demodulator configuration is presented and discussed. The proposed radar presents a unique architecture, using a single channel mixer, and allows to detect contactless vital signs parameters while solving the null point issue and without requiring the small angle approximation condition. Spectral analysis, simulations, and experimental results are presented and detailed to demonstrate the feasibility and the operational principle of the proposed radar architecture.

Impact of Fluidic Chevrons on Jet Noise

NASA Technical Reports Server (NTRS)

Henderson, Brenda S.; Kinzie, Kevin W.; Whitmire, Julia; Abeysinghe, Amal

2005-01-01

The impact of alternating fluidic core chevrons on the production of jet noise is investigated. Core nozzles for a representative 1/9th scale, bypass ratio 5 model system were manufactured with slots cut near the trailing edges to allow for air injection into the core and fan streams. The injectors followed an alternating pattern around the nozzle perimeter so that the injection alternated between injection into the core stream and injection into the fan stream. For the takeoff condition and a forward flight Mach number of 0.10, the overall sound pressure levels at the peak jet noise angle decrease with increasing injection pressure. Sound pressure levels increase for observation angles less than 110o at higher injection pressures due to increases in high frequency noise. Greater increases in high frequency noise are observed when the number of injectors increases from 8 to 12. When the forward flight Mach number is increased to 0.28, jet noise reduction (relative to the baseline) is observed at aft angles for increasing injection pressure while significant increases in jet noise are observed at forward observation angles due to substantial acoustic radiation at high frequencies. A comparison between inflow and alternating injectors shows that, for equal mass injection rates, the inflow nozzle produces greater low frequency noise reduction (relative to the baseline) than the alternating injectors at 90o and aft observation angles and a forward flight Mach number of 0.28. Preliminary computational fluid dynamic simulations indicate that the spatial decay rate of the hot potential core flow is less for the inflow nozzle than for the alternating nozzles which indicates that gentle mixing may be preferred over sever mixing when fluidic chevrons are used for jet noise reduction.

The Influences of Lamination Angles on the Interior Noise Levels of an Aircraft

NASA Technical Reports Server (NTRS)

Fernholz, Christian M.; Robinson, Jay H.

1996-01-01

The feasibility of reducing the interior noise levels of an aircraft passenger cabin through optimization of the composite lay up of the fuselage is investigated. MSC/NASTRAN, a commercially available finite element code, is used to perform the dynamic analysis and subsequent optimization of the fuselage. The numerical calculation of sensitivity of acoustic pressure to lamination angle is verified using a simple thin, cylindrical shell with point force excitations as noise sources. The thin shell used represents a geometry similar to the fuselage and analytic solutions are available for the cylindrical thin shell equations of motion. Optimization of lamination angle for the reduction of interior noise is performed using a finite element model of an actual aircraft fuselage. The aircraft modeled for this study is the Beech Starship. Point forces simulate the structure borne noise produced by the engines and are applied to the fuselage at the wing mounting locations. These forces are the noise source for the optimization problem. The acoustic pressure response is reduced at a number of points in the fuselage and over a number of frequencies. The objective function is minimized with the constraint that it be larger than the maximum sound pressure level at the response points in the passenger cabin for all excitation frequencies in the range of interest. Results from the study of the fuselage model indicate that a reduction in interior noise levels is possible over a finite frequency range through optimal configuration of the lamination angles in the fuselage. Noise reductions of roughly 4 dB were attained. For frequencies outside the optimization range, the acoustic pressure response may increase after optimization. The effects of changing lamination angle on the overall structural integrity of the airframe are not considered in this study.

Tangential synthetic jets for separation control

NASA Astrophysics Data System (ADS)

Esmaeili Monir, H.; Tadjfar, M.; Bakhtian, A.

2014-02-01

A numerical study of separation control has been made to investigate aerodynamic characteristics of a NACA23012 airfoil with a tangential synthetic jet. Simulations are carried out at the chord Reynolds number of Re=2.19×106. The present approach relies on solving the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations. The turbulence model used in the present computation is the Spalart-Allmaras one-equation model. All computations are performed with a finite volume based code. Stall characteristics are significantly improved by controlling the formation of separation vortices in the flow. We placed the synthetic jet at the 12% chord, xj=0.12c, where we expected the separation to occur. Two distinct jet oscillating frequencies: Fj+=0.159 and Fj+=1 were considered. We studied the effect of blowing ratio, Vj/U∞, where it was varied from 0 to 5. The inclined angle of the synthetic jet was varied from αj=0° up to αj=83°. For the non-zero inclined angles, the local maximum in the aerodynamic performance, Cl/Cd, of 6.89 was found for the inclined angle of about 43°. In the present method, by means of creating a dent on the airfoil, linear momentum is transferred to the flow system in tangential direction to the airfoil surface. Thus the absolute maximum of 11.19 was found for the tangential synthetic jet at the inclined angle of the jet of 0°. The mechanisms involved for a tangential jet appear to behave linearly, as by multiplying the activation frequency of the jet by a factor produces the same multiplication factor in the resulting frequency in the flow. However, the mechanisms involved in the non-zero inclined angle cases behave nonlinearly when the activation frequency is multiplied.

Broadband All-angle Negative Refraction by Optimized Phononic Crystals.

PubMed

Li, Yang Fan; Meng, Fei; Zhou, Shiwei; Lu, Ming-Hui; Huang, Xiaodong

2017-08-07

All-angle negative refraction (AANR) of phononic crystals and its frequency range are dependent on mechanical properties of constituent materials and their spatial distribution. So far, it is impossible to achieve the maximum operation frequency range of AANR theoretically. In this paper, we will present a numerical approach for designing a two-dimensional phononic crystal with broadband AANR without negative index. Through analyzing the mechanism of AANR, a topology optimization problem aiming at broadband AANR is established and solved by bi-directional evolutionary structural optimization method. The optimal steel/air phononic crystal exhibits a record AANR range over 20% and its refractive properties and focusing effects are further investigated. The results demonstrate the multifunctionality of a flat phononic slab including superlensing effect near upper AANR frequencies and self-collimation at lower AANR frequencies.

Development of atmospheric pressure plasma needle jet for sterilization applications

NASA Astrophysics Data System (ADS)

Elfa, Rizan Rizon; Ahmad, Mohd Khairul; Soon, Chin Fhong; Sahdan, Mohd Zainizan; Lias, Jais; Wibowo, Kusnanto Mukti; Bakar, Ahmad Shuhaimi Abu; Arshad, Mohd Khairuddin Md; Hashim, Uda; Nayan, Nafarizal

2017-09-01

Inactivation of bacteria or sterilization has been a major issue in the medical field, especially regarding of human safety, whereby, in a huge scenario fatality can be caused by hazardous bacteria. Often, E-coli as gram-negative bacteria are selected as a key indicator of proper sterilization process as E-coli is tough and dormant bacteria. The technology in sterilization has moved on from chemical, wet and irradiation sterilization to a high promising device such as atmospheric pressure plasma needle jet (APPNJ). It has been reported that atmospheric pressure plasma has provided bundle of advantages over earlier sterilization process. The APPNJ is developed in our lab using high frequency and high voltage neon transformer power supply connected to copper needle and copper sheet electrodes. The gas discharge is Ar gas flowing at 40 L/min through a quartz glass tube. The E-coli bacteria are self-cultured from waste water and then treated with APPNJ. The treatment processes are run into two difference gaps between the plasma orifice and sample with various treatment times. Only 40s is required by direct treatment to achieve 100% killing of E-coli. On the other hand, indirect treatment has inactivated 50% of the E-coli in 40s. In this study, direct and indirect effect of APPNJ to the E-coli can be observed which can be utilized into sterilization of bio-compatible material applications.

Evaluation of the Effects of Acupuncture on Blood Flow in Humans with Ultrasound Color Doppler Imaging

PubMed Central

Takayama, Shin; Watanabe, Masashi; Kusuyama, Hiroko; Nagase, Satoru; Seki, Takashi; Nakazawa, Toru; Yaegashi, Nobuo

2012-01-01

Color Doppler imaging (CDI) can be used to noninvasively create images of human blood vessels and quantitatively evaluate blood flow in real-time. The purpose of this study was to assess the effects of acupuncture on the blood flow of the peripheral, mesenteric, and retrobulbar arteries by CDI. Statistical significance was defined as P values less than 0.05. Blood flow in the radial and brachial arteries was significantly lower during needle stimulation on LR3 than before in healthy volunteers, but was significantly higher after needle stimulation than before. LR3 stimulation also resulted in a significant decrease in the vascular resistance of the short posterior ciliary artery and no significant change of blood flow through the superior mesenteric artery (SMA) during acupuncture. In contrast, ST36 stimulation resulted in a significant increase in blood flow through the SMA and no significant change in the vascular resistance of the retrobulbar arteries. Additionally, acupuncture at previously determined acupoints in patients with open-angle glaucoma led to a significant reduction in the vascular resistance of the central retinal artery and short posterior ciliary artery. Our results suggest that acupuncture can affect blood flow of the peripheral, mesenteric, and retrobulbar arteries, and CDI can be useful to evaluate hemodynamic changes by acupuncture. PMID:22778772

Does a paresthesia during spinal needle insertion indicate intrathecal needle placement?

PubMed

Pong, Ryan P; Gmelch, Benjamin S; Bernards, Christopher M

2009-01-01

Paresthesias are relatively common during spinal needle insertion, however, the clinical significance of the paresthesia is unknown. A paresthesia may result from needle-to-nerve contact with a spinal nerve in the epidural space, or, with far lateral needle placement, may result from contact with a spinal nerve within the intervertebral foramen. However, it is also possible and perhaps more likely, that paresthesias occur when the spinal needle contacts a spinal nerve root within the subarachnoid space. This study was designed to test this latter hypothesis. Patients (n = 104) scheduled for surgery under spinal anesthesia were observed during spinal needle insertion. If a paresthesia occurred, the needle was fixed in place and the stylet removed to observe whether cerebrospinal fluid (CSF) flowed from the hub. The presence of CSF was considered proof that the needle had entered the subarachnoid space. Paresthesias occurred in 14/103 (13.6%) of patients; 1 patient experienced a paresthesia twice. All paresthesias were transient. Following a paresthesia, CSF was observed in the needle hub 86.7% (13/15) of the time. Our data suggest that the majority of transient paresthesias occur when the spinal needle enters the subarachnoid space and contacts a spinal nerve root. Therefore, when transient paresthesias occur during spinal needle placement it is appropriate to stop and assess for the presence of CSF in the needle hub, rather than withdraw and redirect the spinal needle away from the side of the paresthesia as some authors have suggested.

Intra-operative navigation of a 3-dimensional needle localization system for precision of irreversible electroporation needles in locally advanced pancreatic cancer.

PubMed

Bond, L; Schulz, B; VanMeter, T; Martin, R C G

2017-02-01

Irreversible electroporation (IRE) uses multiple needles and a series of electrical pulses to create pores in cell membranes and cause cell apoptosis. One of the demands of IRE is the precise needle spacing required. Two-dimensional intraoperative ultrasound (2-D iUS) is currently used to measure inter-needle distances but requires significant expertise. This study evaluates the potential of three-dimensional (3-D) image guidance for placing IRE needles and calculating needle spacing. A prospective clinical evaluation of a 3-D needle localization system (Explorer™) was evaluated in consecutive patients from April 2012 through June 2013 for unresectable pancreatic adenocarcinoma. 3-D reconstructions of patients' anatomy were generated from preoperative CT images, which were aligned to the intraoperative space. Thirty consecutive patients with locally advanced pancreatic cancer were treated with IRE. The needle localization system setup added an average of 6.5 min to each procedure. The 3-D needle localization system increased surgeon confidence and ultimately reduced needle placement time. IRE treatment efficacy is highly dependent on accurate needle spacing. The needle localization system evaluated in this study aims to mitigate these issues by providing the surgeon with additional visualization and data in 3-D. The Explorer™ system provides valuable guidance information and inter-needle distance calculations. Copyright © 2016 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

Method to Reduce Target Motion Through Needle-Tissue Interactions.

PubMed

Oldfield, Matthew J; Leibinger, Alexander; Seah, Tian En Timothy; Rodriguez Y Baena, Ferdinando

2015-11-01

During minimally invasive surgical procedures, it is often important to deliver needles to particular tissue volumes. Needles, when interacting with a substrate, cause deformation and target motion. To reduce reliance on compensatory intra-operative imaging, a needle design and novel delivery mechanism is proposed. Three-dimensional finite element simulations of a multi-segment needle inserted into a pre-existing crack are presented. The motion profiles of the needle segments are varied to identify methods that reduce target motion. Experiments are then performed by inserting a needle into a gelatine tissue phantom and measuring the internal target motion using digital image correlation. Simulations indicate that target motion is reduced when needle segments are stroked cyclically and utilise a small amount of retraction instead of being held stationary. Results are confirmed experimentally by statistically significant target motion reductions of more than 8% during cyclic strokes and 29% when also incorporating retraction, with the same net insertion speed. By using a multi-segment needle and taking advantage of frictional interactions on the needle surface, it is demonstrated that target motion ahead of an advancing needle can be substantially reduced.

Design and Production of an Articulating Needle Guide for Ultrasound-Guided Needle Block Manufactured With a Three-Dimensional Printer: Technical Communication.

PubMed

Bigeleisen, Paul E

2017-05-15

Needle guides may allow the practitioner to align the needle with the probe when ultrasound-guided nerve block is performed. The author's goal was to design and fabricate an inexpensive ($1.90), disposable, needle guide that could articulate over a range from 85 degrees to 0 degrees with a three-dimension printer. Three-dimensional representations of an L50, L25, and C 60 ultrasound probe (Sono Site, Bothell, WA) were created using a laser scanner. Computer-aided design software (Solid Works, Waltham, MA) was used to design a needle bracket and needle guide to attach to these probes. A three-dimensional printer was used to fabricate the needle bracket and guide with acrylonitrile polybutadiene polystyrene. An echogenic needle was held in plane with the needle guide. The author performed a supraclavicular block in a morbidly obese patient. The needle was easily visualized. Similar guides that are commercially available cost as much as $400. A knowledge of computer-aided design is necessary for this work.

Demonstration of a directional sonic prism in two dimensions using an air-acoustic leaky wave antenna

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naify, Christina J., E-mail: christina.naify@nrl.navy.mil; Rohde, Charles A.; Calvo, David C.

Analysis and experimental demonstration of a two-dimensional acoustic leaky wave antenna is presented for use in air. The antenna is comprised of a two-dimensional waveguide patterned with radiating acoustic shunts. When excited using a single acoustic source within the waveguide, the antenna acts as a sonic prism that exhibits frequency steering. This design allows for control of acoustic steering angle using only a single source transducer and a patterned aperture. Aperture design was determined using transmission line analysis and finite element methods. The designed antenna was fabricated and the steering angle measured. The performance of the measured aperture was withinmore » 9% of predicted angle magnitudes over all examined frequencies.« less

Analysis on the electromagnetic scattering properties of crops at multi-band

NASA Astrophysics Data System (ADS)

Wu, Tao; Wu, Zhensen; Liu, Xiaoyi

2014-12-01

The vector radiative transfer (VRT) theory for active microwave remote sensing and Rayleigh-Gans approximation (GRG) are applied in the study, and an iterative algorithm is used to solve the RT equations, thus we obtain the zeroorder and first-order equation for numerical results. The Michigan Microwave Canopy Scattering (MIMICS) model is simplified to adapt to the crop model, by analyzing body-surface bistatic scattering and backscattering properties between a layer of soybean or wheat consisting of stems and leaves and different underlying soil surface at multi-band (i.e. P, L, S, X, Ku-band), we obtain microwave scattering mechanisms of crop components and the effect of underlying ground on total crop scattering. Stem and leaf are regard as a needle and a circular disk, respectively. The final results are compared with some literature data to verify our calculating method, numerical results show multi-band crop microwave scattering properties differ from scattering angle, azimuth angle and moisture of vegetation and soil, which offer the part needed information for the design of future bistatic radar systems for crop sensing applications.

[Deep needling and shallow needling at three acupoints around ear for subjective tinnitus: a randomized controlled trial].

PubMed

Yin, Tao; Ni, Jinxia; Zhu, Wenzeng

2015-10-01

To compare the effective differences between deep needling and shallow needling at three acupoints around ear for subjective tinnitus. Fifty patients with subjective tinnitus were randomized divided into a deep needling group and a shallow needling group, 25 cases in each group. Twenty-two patients in the deep needling group and 20 patients in the shallow needling group were brought into statistic in the end. In the two groups, the three acupoints around ear and distal acupoints were both selected. The acupoints of the affected side such as Yifeng (TE 17), Tinghui (GB 2), Ermen (TE 21), Zhigou (TE 6), Zhongzhu (TE 3) and Hegu (LI 4) were adopted. Yifeng (TE 17), Tinghui (GB 2) and Ermen (TE 21) were acupunctured 30-38 mm in the deep needling group and 15-20 mm in the shallow needling group. The other acupoints were conventionally acupunctured in the two groups. The needles were retained for 30 min,once a day and five times a week for all patients. The treatment was continuously for 4 weeks in the two groups. Tinnitus handicap inventory (THI) scores, tinnitus grades and visual analogue scale (VAS) for tinnitus sound levels were observed before and after treatment, and the effects of the two groups were compared. The total effective rate in the deep needling group was 59.1% (13/22), and it was better than 20.0% (4/20) in the shallow needling group (P < 0.05). In the deep needling, group, the THI score, tinnitus grade and the VAS score were improved than those before treatment (all P < 0.05). In the shallow needling group, the three above indices before and after treatment were not different in statistical significance (all P > 0.05). After treatment, all the three indices in the deep needling group were superior to those in the shallow needling group (all P < 0.05). Acupuncture at the three acupoints around ear deeply could apparently improve tinnitus, and reduce tinnitus sound levels for subjective tinnitus. The effect is better than that by shallow needling at the three acupoints.

Highly Subwavelength, Superdirective Cylindrical Nanoantenna

NASA Astrophysics Data System (ADS)

Arslanagić, Samel; Ziolkowski, Richard W.

2018-06-01

A superdirective cylindrical nanoantenna is demonstrated with a multilayered cylindrical metamaterial-inspired structure. Targeting specific scattering coefficients for the dipole and higher-order modes, the ideal limit of needle radiation is demonstrated. A five-layer system is optimized to demonstrate its approach to the theoretical directivity bound. While the resulting structure is scalable to any frequency regime, its highly subwavelength overall size (λ0/10 ) takes advantage of combinations of positive and negative permittivity materials in the optical regime.

Study and Control of Various Corona Modes in an Atmospheric Pressure Weakly Ionized Plasma Reactor Using a Current Sensor Characterized by a Broad Frequency Band

NASA Astrophysics Data System (ADS)

Islam, Rokibul; Pedrow, Patrick; Lekobou, William; Englund, Karl

2013-09-01

A broad band current sensor is being used to monitor the various phenomena (primary streamers, secondary streamers, back corona, etc.) associated with an atmospheric pressure needle-array-to-grounded-screen corona discharge. The reactor consists of a PVC tube and the needle array consists of nickel coated steel electrodes with radius of curvature about 50 μ . The grounded screen is made from stainless steel mesh and applied voltage has a frequency of 60 Hz with an RMS value ranging from 0 to 10 kV. The voltage sensor is a resistive divider and the current sensor is a viewing resistor with value 50 Ω. The feed gas stream is presently (argon + acetylene) or (argon + oxygen) with the argon acting as carrier gas and the acetylene and oxygen acting as precursor gases. Voltage and current are captured with a LeCroy 9350AL 500MHz oscilloscope and analyzed with Matlab using digital signal processing algorithms. The goals of the research are 1) to measure reactor electrical power on a real time basis; 2) to provide real time control of the applied voltage and thus avoid spark conditions; and 3) to identify the various corona modes present in the reactor. Processing of substrates takes place downstream from the grounded screen, outside of the harsh corona discharge environment.

Parent Cardiac Response in the Context of Their Child’s Completion of the Cold Pressor Task: A Pilot Study

PubMed Central

Constantin, Kaytlin; Moline, Rachel L.; Bailey, Heidi N.

2017-01-01

Parents’ ability to regulate their emotions is essential to providing supportive caregiving behaviours when their child is in pain. Extant research focuses on parent self-reported experience or observable behavioural responses. Physiological responding, such as heart rate (HR) and heart rate variability (HRV), is critical to the experience and regulation of emotions and provides a complementary perspective on parent experience; yet, it is scarcely assessed. This pilot study examined parent (n = 25) cardiac response (HR, HRV) at rest (neutral film clip), immediately before the cold pressor task (pre-CPT), and following the CPT (post-CPT). Further, variables that may influence changes in HR and HRV in the context of pediatric pain were investigated, including (1) initial HRV, and (2) parent perception of their child’s typical response to needle procedures. Time-domain (root mean square of successive differences; RMSSD) and frequency-domain (high-frequency heart rate variability; HF-HRV) parameters of HRV were computed. HR and HF-HRV varied as a function of time block. Typical negative responses to needle pain related to higher parental HR and lower HRV at rest. Parents with higher HRV at baseline experienced the greatest decreases in HRV after the CPT. Consequently, considering previous experience with pain and resting HRV levels are relevant to understanding parent physiological responses before and after child pain. PMID:29160828

Measurement of Non-Linear Internal Waves and Their Interaction with Surface Waves using Coherent Real Aperture Radars

DTIC Science & Technology

2010-03-08

frequencies on wind speed and direction is viable at VV polarization at much larger incidence angles than we had thought. At this polarization it works...out to 89 degree incidence angles. By contrast at HH polarization the model underpredicts the NRCS of the sea for incidence angles above about 45...degrees. ● At high grazing angles, HH polarized cross sections maximize upwind and minimize downwind; upwind they are slightly smaller than VV

Effects of insertion speed and trocar stiffness on the accuracy of needle position for brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGill, Carl S.; Schwartz, Jonathon A.; Moore, Jason Z.

2012-04-15

Purpose: In prostate brachytherapy, accurate positioning of the needle tip to place radioactive seeds at its target site is critical for successful radiation treatment. During the procedure, needle deflection leads to seed misplacement and suboptimal radiation dose to cancerous cells. In practice, radiation oncologists commonly use high-speed hand needle insertion to minimize displacement of the prostate as well as the needle deflection. Effects of speed during needle insertion and stiffness of trocar (a solid rod inside the hollow cannula) on needle deflection are studied. Methods: Needle insertion experiments into phantom were performed using a 2{sup 2} factorial design (2 parametersmore » at 2 levels), with each condition having replicates. Analysis of the deflection data included calculating the average, standard deviation, and analysis of variance (ANOVA) to find significant single and two-way interaction factors. Results: The stiffer tungsten carbide trocar is effective in reducing the average and standard deviation of needle deflection. The fast insertion speed together with the stiffer trocar generated the smallest average and standard deviation for needle deflection for almost all cases. Conclusions: The combination of stiff tungsten carbide trocar and fast needle insertion speed are important to decreasing needle deflection. The knowledge gained from this study can be used to improve the accuracy of needle insertion during brachytherapy procedures.« less

Incidence of tissue coring with the 25-gauge Quincke and Whitacre spinal needles.

PubMed

Campbell, D C; Douglas, M J; Taylor, G

1996-01-01

Tissue cores, implanted into the subarachnoid space during subarachnoid injections, can develop into intraspinal lumbar epidermoid tumors. The availability of smaller needles has made spinal anesthesia more popular. Therefore, this prospective, randomized, blinded study was undertaken to determine whether tissue coring occurs with two of the currently used 25-gauge spinal needles. Fifteen 25-gauge Quincke and seventeen 25-gauge Whitacre spinal needles, in which cerebrospinal fluid (CSF) was not identified and the local anesthetic solution not injected, were obtained from adult male patients undergoing spinal anesthesia. The needles were then evaluated by a pathologist following randomization with similar sterile, unused spinal needles. Twenty additional needles, ten of each type, in which CSF was identified and through which local anesthetic was injected, were also randomized with similar sterile, unused spinal needles and examined. Tissue cores were identified in 12 of the 15 Quincke and 7 of the 17 Whitacre spinal needles in which CSF was not identified (P < .05). Of the 20 needles in which CSF was identified and local anesthetic injected, no tissue cores were identified in the 10 Whitacre needles and only one small tissue core was identified in the 10 Quincke needles. All the tissue cores were identified as fat tissue. The 25-gauge Quincke and 25-gauge Whitacre spinal needles currently used in anesthesia can produce tissue coring.

Options for reducing HIV transmission related to the dead space in needles and syringes.

PubMed

Zule, William A; Pande, Poonam G; Otiashvili, David; Bobashev, Georgiy V; Friedman, Samuel R; Gyarmathy, V Anna; Des Jarlais, Don C

2018-01-15

When shared by people who inject drugs, needles and syringes with different dead space may affect the probability of HIV and hepatitis C virus (HCV) transmission differently. We measured dead space in 56 needle and syringe combinations obtained from needle and syringe programs across 17 countries in Europe and Asia. We also calculated the amounts of blood and HIV that would remain in different combinations following injection and rinsing. Syringe barrel capacities ranged from 0.5 to 20 mL. Needles ranged in length from 8 to 38 mm. The average dead space was 3 μL in low dead space syringes with permanently attached needles, 13 μL in high dead space syringes with low dead space needles, 45 μL in low dead space syringes with high dead space needles, and 99 μL in high dead space syringes with high dead space needles. Among low dead space designs, calculated volumes of blood and HIV viral burden were lowest for low dead space syringes with permanently attached needles and highest for low dead space syringes with high dead space needles. The dead space in different low dead space needle and syringe combinations varied substantially. To reduce HIV transmission related to syringe sharing, needle and syringe programs need to combine this knowledge with the needs of their clients.

Ultrasound-guided fine needle aspiration versus core needle biopsy: comparison of post-biopsy hematoma rates and risk factors.

PubMed

Chae, In Hye; Kim, Eun-Kyung; Moon, Hee Jung; Yoon, Jung Hyun; Park, Vivian Y; Kwak, Jin Young

2017-07-01

To compare post-biopsy hematoma rates between ultrasound guided-fine needle aspiration and ultrasound guided-core needle biopsy, and to investigate risk factors for post-biopsy hematoma. A total of 5304 thyroid nodules which underwent ultrasound guided biopsy were included in this retrospective study. We compared clinical and US features between patients with and without post-biopsy hematoma. Associations between these features and post-biopsy hematoma were analyzed. Post-biopsy hematoma rate was 0.8% (43/5121) for ultrasound guided-fine needle aspiration and 4.9% (9/183) for ultrasound guided-core needle biopsy (P < 0.001). For ultrasound guided-fine needle aspiration, gender, age, size, presence of vascularity, and suspicious US features were not associated with post-biopsy hematoma according to experience level. Post-biopsy hematoma occurred significantly more with ultrasound guided-core needle biopsy (9/179, 5.0%) than with ultrasound guided-fine needle aspiration (9/1138, 0.8%) (P < 0.001) in experienced performers and ultrasound guided-core needle biopsy was the only significant risk factor for post-biopsy hematoma (adjusted Odds Ratio, 6.458, P < 0.001). Post-biopsy hematoma occurred significantly more in ultrasound guided-core needle biopsy than in ultrasound guided-fine needle aspiration and ultrasound guided-core needle biopsy was the only independent factor of post-biopsy hematoma in thyroid nodules.

New method to monitor RF safety in MRI-guided interventions based on RF induced image artefacts.

PubMed

van den Bosch, Michiel R; Moerland, Marinus A; Lagendijk, Jan J W; Bartels, Lambertus W; van den Berg, Cornelis A T

2010-02-01

Serious tissue heating may occur at the tips of elongated metallic structures used in MRI-guided interventions, such as vascular guidewires, catheters, biopsy needles, and brachytherapy needles. This heating is due to resonating electromagnetic radiofrequency (RF) waves along the structure. Since it is hard to predict the exact length at which resonance occurs under in vivo conditions, there is a need for methods to monitor this resonance behavior. In this study, the authors propose a method based on the RF induced image artefacts and demonstrate its applicability in two phantom experiments. The authors developed an analytical model that describes the RF induced image artefacts as a function of the induced current in an elongated metallic structure placed parallel to the static magnetic field. It describes the total RF field as a sum of the RF fields produced by the transmit coil of the MR scanner and by the elongated metallic structure. Several spoiled gradient echo images with different nominal flip angle settings were acquired to map the B1+ field, which is a quantitative measure for the RF distortion around the structure. From this map, the current was extracted by fitting the analytical model. To investigate the sensitivity of our method we performed two phantom experiments with different setup parameters: One that mimics a brachytherapy needle insertion and one that resembles a guidewire intervention. In the first experiment, a short needle was placed centrally in the MR bore to ensure that the induced currents would be small. In the second experiment, a longer wire was placed in an off-center position to mimic a worst case scenario for the patient. In both experiments, a Luxtron (Santa Clara, CA) fiberoptic temperature sensor was positioned at the structure tip to record the temperature. In the first experiment, no significant temperature increases were measured, while the RF image artefacts and the induced currents in the needle increased with the applied insertion depth. The maximum induced current in the needle was 44 mA. Furthermore, a standing wave pattern became clearly visible for larger insertion depths. In the second experiment, significant temperature increases up to 2.4 degrees C in 1 min were recorded during the image acquisitions. The maximum current value was 1.4 A. In both experiments, a proper estimation of the current in the metallic structure could be made using our analytical model. The authors have developed a method to quantitatively determine the induced current in an elongated metallic structure from its RF distortion. This creates a powerful and sensitive method to investigate the resonant behavior of RF waves along elongated metallic structures used for MRI-guided interventions, for example, to monitor the RF safety or to inspect the influence of coating on the resonance length. Principally, it can be applied under in vivo conditions and for noncylindrical metallic structures such as hip implants by taking their geometry into account.

Free-Space Time-Domain Method for Measuring Thin Film Dielectric Properties

DOEpatents

Li, Ming; Zhang, Xi-Cheng; Cho, Gyu Cheon

2000-05-02

A non-contact method for determining the index of refraction or dielectric constant of a thin film on a substrate at a desired frequency in the GHz to THz range having a corresponding wavelength larger than the thickness of the thin film (which may be only a few microns). The method comprises impinging the desired-frequency beam in free space upon the thin film on the substrate and measuring the measured phase change and the measured field reflectance from the reflected beam for a plurality of incident angles over a range of angles that includes the Brewster's angle for the thin film. The index of refraction for the thin film is determined by applying Fresnel equations to iteratively calculate a calculated phase change and a calculated field reflectance at each of the plurality of incident angles, and selecting the index of refraction that provides the best mathematical curve fit with both the dataset of measured phase changes and the dataset of measured field reflectances for each incident angle. The dielectric constant for the thin film can be calculated as the index of refraction squared.

Experimental investigation of unsteady flows at large incidence angles in a linear oscillating cascade

NASA Technical Reports Server (NTRS)

Buffum, Daniel H.; King, Aaron J.; Capece, Vincent R.; El-Aini, Yehia M.

1996-01-01

The aerodynamics of a cascade of airfoils oscillating in torsion about the midchord is investigated experimentally at a large mean incidence angle and, for reference, at a low mean incidence angle. The airfoil section is representative of a modern, low aspect ratio, fan blade tip section. Time-dependent airfoil surface pressure measurements were made for reduced frequencies up to 0.8 for out-of-phase oscillations at Mach numbers up to 0.8 and chordal incidence angles of 0 deg and 10 deg. For the 10 deg chordal incidence angle, a separation bubble formed at the leading edge of the suction surface. The separated flow field was found to have a dramatic effect on the chordwise distribution of the unsteady pressure. In this region, substantial deviations from the attached flow data were found with the deviations becoming less apparent in the aft region of the airfoil for all reduced frequencies. In particular, near the leading edge the separated flow had a strong destabilizing influence while the attached flow had a strong stabilizing influence.

Influence of handrim wheelchair propulsion training in adolescent wheelchair users, a pilot study.

PubMed

Dysterheft, Jennifer L; Rice, Ian M; Rice, Laura A

2015-01-01

Ten full-time adolescent wheelchair users (ages 13-18) completed a total of three propulsion trials on carpet and tile surfaces, at a self-selected velocity, and on a concrete surface, at a controlled velocity. All trials were performed in their personal wheelchair with force and moment sensing wheels attached bilaterally. The first two trials on each surface were used as pre-intervention control trials. The third trial was performed after receiving training on proper propulsion technique. Peak resultant force, contact angle, stroke frequency, and velocity were recorded during all trials for primary analysis. Carpet and tile trials resulted in significant increases in contact angle and peak total force with decreased stroke frequency after training. During the velocity controlled trials on concrete, significant increases in contact angle occurred, as well as decreases in stroke frequency after training. Overall, the use of a training video and verbal feedback may help to improve short-term propulsion technique in adolescent wheelchair users and decrease the risk of developing upper limb pain and injury.

Comparison of 21-Gauge and 22-Gauge Aspiration Needle in Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration

PubMed Central

Akulian, Jason; Lechtzin, Noah; Yasin, Faiza; Kamdar, Biren; Ernst, Armin; Ost, David E.; Ray, Cynthia; Greenhill, Sarah R.; Jimenez, Carlos A.; Filner, Joshua; Feller-Kopman, David

2013-01-01

Background: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive procedure originally performed using a 22-gauge (22G) needle. A recently introduced 21-gauge (21G) needle may improve the diagnostic yield and sample adequacy of EBUS-TBNA, but prior smaller studies have shown conflicting results. To our knowledge, this is the largest study undertaken to date to determine whether the 21G needle adds diagnostic benefit. Methods: We retrospectively evaluated the results of 1,299 patients from the American College of Chest Physicians Quality Improvement Registry, Education, and Evaluation (AQuIRE) Diagnostic Registry who underwent EBUS-TBNA between February 2009 and September 2010 at six centers throughout the United States. Data collection included patient demographics, sample adequacy, and diagnostic yield. Analysis consisted of univariate and multivariate hierarchical logistic regression comparing diagnostic yield and sample adequacy of EBUS-TBNA specimens by needle gauge. Results: A total of 1,235 patients met inclusion criteria. Sample adequacy was obtained in 94.9% of the 22G needle group and in 94.6% of the 21G needle group (P = .81). A diagnosis was made in 51.4% of the 22G and 51.3% of the 21G groups (P = .98). Multivariate hierarchical logistic regression showed no statistical difference in sample adequacy or diagnostic yield between the two groups. The presence of rapid onsite cytologic evaluation was associated with significantly fewer needle passes per procedure when using the 21G needle (P < .001). Conclusions: There is no difference in specimen adequacy or diagnostic yield between the 21G and 22G needle groups. EBUS-TBNA in conjunction with rapid onsite cytologic evaluation and a 21G needle is associated with fewer needle passes compared with a 22G needle. PMID:23632441

NMR Model of PrgI-SipD Interaction and its Implications in the Needle-Tip Assembly of the Salmonella Type III Secretion System

PubMed Central

Rathinavelan, Thenmalarchelvi; Lara-Tejero, Maria; Lefebre, Matthew; Chatterjee, Srirupa; McShan, Andrew C.; Guo, Da-Chuan; Tang, Chun; Galan, Jorge E.; De Guzman, Roberto N.

2014-01-01

Salmonella and other pathogenic bacteria use the type III secretion system (T3SS) to inject virulence proteins into human cells to initiate infections. The structural component of the T3SS contains a needle and a needle tip. The needle is assembled from PrgI needle protomers and the needle tip is capped with several copies of the SipD tip protein. How a tip protein docks on the needle is unclear. A crystal structure of a PrgI-SipD fusion protein docked on the PrgI needle results in steric clash of SipD at the needle tip when modeled on the recent atomic structure of the needle. Thus, there is currently no good model of how SipD is docked on the PrgI needle tip. Previously, we showed by NMR paramagnetic relaxation enhancement (PRE) methods that a specific region in the SipD coiled-coil is the binding site for PrgI. Others have hypothesized that a domain of the tip protein – the N-terminal α-helical hairpin, has to swing away during the assembly of the needle apparatus. Here, we show by PRE methods that a truncated form of SipD lacking the α-helical hairpin domain binds more tightly to PrgI. Further, PRE-based structure calculations revealed multiple PrgI binding sites on the SipD coiled-coil. Our PRE results together with the recent NMR-derived atomic structure of the Salmonella needle suggest a possible model of how SipD might dock at the PrgI needle tip. SipD and PrgI are conserved in other bacterial T3SSs, thus our results have wider implication in understanding other needle-tip complexes. PMID:24951833

Methods for prostate stabilization during transperineal LDR brachytherapy.

PubMed

Podder, Tarun; Sherman, Jason; Rubens, Deborah; Messing, Edward; Strang, John; Ng, Wan-Sing; Yu, Yan

2008-03-21

In traditional prostate brachytherapy procedures for a low-dose-rate (LDR) radiation seed implant, stabilizing needles are first inserted to provide some rigidity and support to the prostate. Ideally this will provide better seed placement and an overall improved treatment. However, there is much speculation regarding the effectiveness of using regular brachytherapy needles as stabilizers. In this study, we explored the efficacy of two types of needle geometries (regular brachytherapy needle and hooked needle) and several clinically feasible configurations of the stabilization needles. To understand and assess the prostate movement during seed implantation, we collected in vivo data from patients during actual brachytherapy procedures. In vitro experimentation with tissue-equivalent phantoms allowed us to further understand the mechanics behind prostate stabilization. We observed superior stabilization with the hooked needles compared to the regular brachytherapy needles (more than 40% in bilateral parallel needle configuration). Prostate movement was also reduced significantly when regular brachytherapy needles were in an angulated configuration as compared to the parallel configuration (more than 60%). When the hooked needles were angulated for stabilization, further reduction in prostate displacement was observed. In general, for convenience of dosimetric planning and to avoid needle collision, all needles are desired to be in a parallel configuration. In this configuration, hooked needles provide improved stabilization of the prostate. On the other hand, both regular and hooked needles appear to be equally effective in reducing prostate movement when they are in angulated configurations, which will be useful in seed implantation using a robotic system. We have developed nonlinear spring-damper model for the prostate movement which can be used for adapting dosimetric planning during brachytherapy as well as for developing more realistic haptic devices and training simulators.

Point-to-plane and plane-to-plane electrostatic charge injection atomization for insulating liquids

NASA Astrophysics Data System (ADS)

Malkawi, Ghazi

An electrostatic charge injection atomizer was fabricated and used to introduce and study the electrostatic charge injection atomization methods for highly viscous vegetable oils and high conductivity low viscosity aviation fuel, JP8. The total, spray and leakage currents and spray breakup characteristics for these liquids were investigated and compared with Diesel fuel data. Jet breakup and spray atomization mechanism showed differences for vegetable oils and lower viscosity hydrocarbon fuels. For vegetable oils, a bending/spinning instability phenomenon was observed similar to the phenomenon found in liquid jets of high viscosity polymer solutions. The spray tip lengths and cone angles were presented qualitatively and quantitatively and correlated with the appropriate empirical formulas. The different stages of the breakup mechanisms for such oils, as a function of specific charges and flow rates, were discussed. In order to make this method of atomization more suitable for practical use in high flow rate applications, a blunt face electrode (plane-to-plane) was used as the charge emitter in place of a single pointed electrode (point-to-plane). This allowed the use of a multi-orifice emitter that maintained a specific charge with the flow rate increase which could not be achieved with the needle electrode. The effect of the nozzle geometry, liquid physical properties and applied bulk flow on the spray charge, total charge, maximum critical spray specific charge and electrical efficiency compared with the needle point-to-plane atomizer results was presented. Our investigation revealed that the electrical efficiency of the atomizer is dominated by the charge forced convection rate rather than charge transport by ion motilities and liquid motion by the electric field. As a result of the electric coulomb forces between the electrified jets, the multi-orifice atomizer provided a unique means of dispersing the fuel in a hollow cone with wide angles making the new method suitable for variety of combustion applications.

Three reversible polymorphic copper(I) complexes triggered by ligand conformation: insights into polymorphic crystal habit and luminescent properties.

PubMed

Chai, Wenxiang; Hong, Mingwei; Song, Li; Jia, Guohua; Shi, Hongsheng; Guo, Jiayu; Shu, Kangying; Guo, Bing; Zhang, Yicheng; You, Wenwu; Chen, Xueyuan

2015-05-04

Three luminescent polymorphs based on a new copper(I) complex Cu(2-QBO)(PPh3)PF6 (1, PPh3 = triphenylphosphine, 2-QBO = 2-(2'-quinolyl)benzoxazole) have been synthesized and characterized by FT-IR, UV-vis, elemental analyses, and single-crystal X-ray diffraction analyses. Each polymorph can reversibly convert from one to another through appropriate procedures. Interestingly, such interconversion can be distinguished by their intrinsic crystal morphologies and colors (namely α, dark yellow plate, β, orange block, γ, light yellow needle) as well as photoluminescent (PL) properties. X-ray crystal structure analyses of these three polymorphs show three different supramolecular structures from 1D to 3D, which are expected to be responsible for the formation of three different crystal morphologies such as needle, plate, and block. Combination of the experimental data with DFT calculations on these three polymorphs reveals that the polymorphic interconversion is triggered by the conformation isomerization of the 2-QBO ligand and can be successfully controlled by the polarity of the process solvents (affecting the molecular dipole moment) and thermodynamics (affecting the molecular total energy). It is also found that the different crystal colors of polymorphs and their PL properties are derived from different θ values (dihedral angle between benzoxazolyl and quinolyl group of the 2-QBO ligand) and P-Cu-P angles based on TD-DFT calculations. Moreover, an interesting phase interconversion between γ and β has also been found under different temperature, and this result is consistent with the DFT calculations in which the total energy of β is larger than that of γ. This polymorphism provides a good model to study the relationship between the structure and the physical properties in luminescent copper(I) complexes as well as some profound insights into their PL properties.

SURGICAL OUTCOME OF SIMULTANEOUS INTRAOCULAR LENS RESCUE AND SUTURELESS INTRASCLERAL TUNNEL FIXATION OF DISLOCATED INTRAOCULAR LENSES.

PubMed

Kim, Min; Lee, Dong H; Koh, Hyoung J; Lee, Sung C; Kim, Sung S

2015-07-01

To report short-term surgical outcomes of single-stage simultaneous rescue and sutureless intrascleral fixation of dislocated intraocular lens (IOLs). Sixteen eyes of 16 patients who underwent simultaneous rescue and intrascleral fixation of dislocated 3-piece IOLs were retrospectively evaluated. Partial thickness limbal-based scleral flaps (2.0 × 2.0 mm) were created, and a 22-gauge round needle was used to create a sclerotomy at 1.5 mm from the limbus under the previously created scleral flap, and a 23-gauge trans pars plana vitrectomy was performed. Bimanual maneuvers using two 23-gauge end-grasping forceps under chandelier illumination and a wide-angle viewing system enabled 1 step rescue of IOLs from the posterior vitreous cavity with 1 hand and simultaneous haptic externalization through sclerotomy with the other hand. An externalized haptic was placed into the 3-mm intrascleral tunnel created using a bent 26-gauge needle. Fibrin glue was used to fixate haptics and close the scleral flaps. Intraocular lenses were successfully rescued and sclera-fixated through intrascleral tunnels in all 16 eyes (mean age, 56.56 ± 19.89 years). The mean preoperative logarithm of the minimum angle of resolution best-corrected visual acuity was 0.92 ± 0.68, and this significantly improved at 6 months to 0.289 ± 0.36 (P = 0.003). During the follow-up period (10.1 ± 3.21 months), no significant change of endothelial cell count or central foveal thickness was noted postoperatively (P = 0.203 and P = 0.979, respectively). There were no significant postoperative complications such as IOL dislocation, IOL decentration, retinal detachment, endophthalmitis, or postoperative hypotony. Simultaneous rescue and sutureless intrascleral haptic fixation of dislocated 3-piece IOLs using bimanual maneuvers is an effective, safe, and minimally invasive surgical method to rescue and fixate the dislocated IOL without further explant.

Methods and apparatuses for self-generating fault-tolerant keys in spread-spectrum systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moradi, Hussein; Farhang, Behrouz; Subramanian, Vijayarangam

Self-generating fault-tolerant keys for use in spread-spectrum systems are disclosed. At a communication device, beacon signals are received from another communication device and impulse responses are determined from the beacon signals. The impulse responses are circularly shifted to place a largest sample at a predefined position. The impulse responses are converted to a set of frequency responses in a frequency domain. The frequency responses are shuffled with a predetermined shuffle scheme to develop a set of shuffled frequency responses. A set of phase differences is determined as a difference between an angle of the frequency response and an angle ofmore » the shuffled frequency response at each element of the corresponding sets. Each phase difference is quantized to develop a set of secret-key quantized phases and a set of spreading codes is developed wherein each spreading code includes a corresponding phase of the set of secret-key quantized phases.« less

[Try to discuss manipulation of the "Feijing Zouqi" needling technique].

PubMed

Zhou, Dan; Gao, Ying; Wang, Fu-chun

2008-03-01

Based on description of "Feijing Zouqi" needling methods in Jin Zhen Fu (Rhyme Prose of Golden Needle) written by Xu Feng, and explain and analyze the descriptions of "Feijing Zouqi" needling method in Zhenjiu Juying (A Collection of Gems in Acu-Moxibustion) written by Gao Wu, Zhenjiu Wendui written by Wang Ji, Zhenjiu Dacheng (Great Compendium on Acu-Moxibustion) written by Yang Ji-zhou, Yixue Rumen (Elementary Medicine) written by LI Chan and many other works, summarize the technique characteristics of all the "Feijing Zouqi" needling methods. The characteristic of "Qinglong Baiwei" needling method is " first toward the left, then toward the right, slowly move or adjust with the hand"; and "Baihu Yaotou" needling method emphasizes "Tuifang Jinyuan" and "Yaozhen "; key point of "Canggui Tanxue" needling method is "Zuanti Sifang"; Chifeng Yingyuan" needling method emphasizes "Siwei Feixuan".

Gallium-67 uptake by the thyroid associated with progressive systemic sclerosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sjoberg, R.J.; Blue, P.W.; Kidd, G.S.

1989-01-01

Although thyroidal uptake of gallium-67 has been described in several thyroid disorders, gallium-67 scanning is not commonly used in the evaluation of thyroid disease. Thyroidal gallium-67 uptake has been reported to occur frequently with subacute thyroiditis, anaplastic thyroid carcinoma, and thyroid lymphoma, and occasionally with Hashimoto's thyroiditis and follicular thyroid carcinoma. A patient is described with progressive systemic sclerosis who, while being scanned for possible active pulmonary involvement, was found incidentally to have abnormal gallium-67 uptake only in the thyroid gland. Fine needle aspiration cytology of the thyroid revealed Hashimoto's thyroiditis. Although Hashimoto's thyroiditis occurs with increased frequency in patientsmore » with progressive systemic sclerosis, thyroidal uptake of gallium-67 associated with progressive systemic sclerosis has not, to our knowledge, been previously described. Since aggressive thyroid malignancies frequently are imaged by gallium-67 scintigraphy, fine needle aspiration cytology of the thyroid often is essential in the evaluation of thyroidal gallium-67 uptake.« less

Injection practices among practitioners in private medical clinics of Karachi, Pakistan.

PubMed

Yousafzai, M T; Nisar, N; Kakakhel, M F; Qadri, M H; Khalil, R; Hazara, S M

2013-06-01

The aim of this study was to determine the frequency and determinants of sharps injuries among private health practitioners in slum areas of Karachi, Pakistan. All practitioners with at least 1 year of experience in a private medical clinic were asked to complete a self-administered, structured questionnaire (317/397 responded). Only 7.9% of practitioners were qualified from medical school, 12.3% were registered nurses and 8.8% lacked any professional qualifications. At least 1 sharps injury in the previous 12 months was reported by 26.7%, mostly due to needle recapping. Only 25.2% reported using a new syringe for each patient. In multivariate regression analysis shorter work experience, < 14 years of schooling, > 20 patients per day, administering > or = 30 injections per day, reuse of syringes and needle recapping after use were significantly associated with sharps injury in the past year. Better awareness and training on standard precautions is needed for private practitioners in slum areas of Karachi.

Pressure gradient induced generation of microbubbles

NASA Astrophysics Data System (ADS)

Evangelio, Alvaro; Campo-Cortes, Francisco; Gordillo, Jose Manuel

2015-11-01

It is well known that the controlled production of monodisperse bubbles possesses uncountable applications in medicine, pharmacy and industry. Here we provide with a detailed physical description of the bubble formation processes taking place in a type of flow where the liquid pressure gradient can be straightforwardly controlled. In our experiments, a gas flow rate discharges through a cylindrical needle into a pressurized chamber. The pressure gradient created from the exit of the injection needle towards the entrance of a extraction duct promotes the stretching of the gas ligament downstream. In our analysis, which is supported by an exhaustive experimental study in which the liquid viscosity is varied by three orders of magnitude, different regimes can be distinguished depending mainly on the Reynolds number. Through our physical modeling, we provide closed expressions for both the bubbling frequencies and for the bubble diameters as well as the conditions under which a monodisperse generation is obtained in all regimes found. The excellent agreement between our expressions and the experimental data fully validates our physical modeling.

Mediastinal abscess after endobronchial ultrasound-guided transbronchial needle aspiration: a case report and literature review.

PubMed

Leong, Steven C; Marshall, Henry M; Bint, Michael; Yang, Ian A; Bowman, Rayleen V; Fong, Kwun M

2013-10-01

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive technique that allows lung cancer nodal staging and biopsy of parabronchial and paratracheal tissue. Its simplicity, high diagnostic yield, ability to diagnose both benign and malignant conditions, and exceedingly low complication rate has resulted in rapid widespread adoption by surgeons and physicians. EBUS-TBNA-related complications, however, do occur and need to be considered when assessing the risk-benefit profile of performing the procedure, and if the patient represents with unexpected symptoms after the procedure. We describe a 64-year-old woman who presented with a mediastinal abscess 5 days after EBUS-TBNA. This case demonstrates the importance of considering EBUS-TBNA-related complications to guide relevant imaging decisions and antibiotic choices. We review the published literature regarding infective complications of EBUS-TBNA and propose possible pathophysiologies. These complications are likely to increase in frequency as the technique is more widely adopted.

Effect of fuel and nozzle geometry on the off-axis oscillation of needle in diesel injectors using high-speed X-ray phase contrast imaging

NASA Astrophysics Data System (ADS)

Zhang, X.; Liu, J.; Wang, J.

2016-05-01

The diesel spray characteristics are strongly influenced by the flow dynamics inside the injector nozzle. Moreover, the off-axis oscillation of needle could lead to variation of orifice flow in the nozzle. In this paper, the needle oscillation was investigated using high-speed X-ray phase contrast imaging and quantitative image processing. The effects of fuel, injection pressure and nozzle geometry on the needle oscillation were analyzed. The results showed that the vertical and horizontal oscillation of needle was independent on the injection pressure. The maximum oscillation range of 14μ m was found. Biodiesel application slightly decreased the needle oscillation due to high viscosity. The needle oscillation range increased generally with increasing hole number. The larger needle oscillation in multi-hole injectors was dominated by the geometry problem or production issue at lower needle lift. In addition, the influence of needle oscillation on the spray morphology was also discussed.

Is Skin-Touch Sham Needle Not Placebo? A Double-Blind Crossover Study on Pain Alleviation

PubMed Central

Homma, Ikuo; Izumizaki, Masahiko

2015-01-01

It remains an open question whether placebo/sham acupuncture, in which the needle tip presses the skin, can be used as a placebo device for research on pain. We compare the analgesic effect of the skin-touch placebo needle with that of the no-touch placebo needle, in which the needle tip does not touch the skin, in a double-blind crossover manner including no-treatment control in 23 healthy volunteers. The subjects received painful electrical stimulation in the forearm before and during needle retention to the LI 4 acupoint and after the removal of the needle and rated pain intensity using a visual analogue scale. We found no significant difference in analgesic effects among the skin-touch placebo needle, no-touch placebo needle, and no-treatment control at every point before, during, and after the treatments (p > 0.05). The results indicate that the skin-touch placebo needle can be used as a placebo device in clinical studies on pain. PMID:26064153

Difficulties in spinal needle use. Insertion characteristics and failure rates associated with 25-, 27- and 29-gauge Quincke-type spinal needles.

PubMed

Tarkkila, P; Huhtala, J; Salminen, U

1994-08-01

The effect of different size (25-, 27- and 29-gauge) Quincke-type spinal needles on the incidence of insertion difficulties and failure rates was investigated in a randomised, prospective study with 300 patients. The needle size was randomised but the insertion procedure was standardised. The time to achieve dural puncture was significantly longer with the 29-gauge spinal needle compared with the larger bore needles and was due to the greater flexibility of the thin needle. However, the difference was less than 1 min and cannot be considered clinically significant. There were no significant differences between groups in the number of insertion attempts or failures and the same sensory level of analgesia was reached with all the needle sizes studied. Postoperatively, no postdural puncture headaches occurred in the 29-gauge spinal needle group, whilst in the 25- and 27-gauge needle groups, the postdural puncture headache rates were 7.4% and 2.1% respectively. The incidence of backache was similar in all study groups. We conclude that dural puncture with a 29-gauge spinal needle is clinically as easy as with larger bore needles and its use is indicated in patients who have a high risk of postdural puncture headache.

Development of Repulsive Barrier Discharge from Twin Needles

NASA Astrophysics Data System (ADS)

Ueno, Hideki; Hata, Koji; Nakayama, Hiroshi

2007-03-01

Barrier discharge characteristics have been investigated for a twin needles-to-plane electrode configuration in dry air. The characteristics of barrier discharge under ac voltage application have been investigated for various distances between two needle tips (d=1.0--4.0 mm). We have found that corona discharge behavior strongly depends on needle-tip distance. In the case of a twin-needles configuration with a long needle-tip distance (d=4.0 mm), discharges from the two needle tips develop into a dielectric barrier with almost a straight path. On the contrary, the development of repulsive discharges from two needle tips in the gap between needles and a barrier was obtained for the shortest needle-tip distance investigated here (d=1.0 mm) and it was enhanced by increasing the peak voltage. From detailed time-resolved observations, development of repulsive discharge was observed only during positive polarity upon ac voltage application. Moreover, the degree of repulsion increased with increasing applied voltage of positive polarity. The observed unique discharge behavior can be interpreted as the effect of field relaxation induced not only by charge accumulation on the barrier surface, which is markedly enhanced at a short needle-tip distance, but also by space charge by coronas between two needles.

The effects of soil moisture and plant morphology on the radar backscatter from vegetation

NASA Technical Reports Server (NTRS)

Ulaby, F. T.; Bush, T. F.; Batlivala, P. P.; Cihlar, J.

1974-01-01

The results of experimental studies on the backscattering properties of corn, milo, soybeans and alfalfa are presented. The measurements were made during the summer of 1973 over the 8 to 18 GHz frequency band. The data indicate that soil moisture estimation is best accomplished at incidence angles near nadir with lower frequencies, while crop discrimination is best accomplished using two frequencies at incidence angles ranging from 30 deg to 65 deg. It is also shown that temporal plant morphology variations can cause extreme variations in the values of the scattering coefficients. These morphological changes can be caused by growth, heavy rain and in the case of alfalfa, harvesting.

The effects of needle deformation during lumbar puncture.

PubMed

Özdemir, Hasan Hüseyin; Demir, Caner F; Varol, Sefer; Arslan, Demet; Yıldız, Mustafa; Akil, Eşref

2015-01-01

The aim of this study is to assess deformation of the tip and deflection from the axis of 22-gauge Quincke needles when they are used for diagnostic lumbar puncture (LP). Thus, it can be determined whether constructional alterations of needles are important for predicting clinical problems after diagnostic LP. The 22-gauge Quincke needles used for diagnostic LP were evaluated. A specially designed protractor was used for measurement and evaluation. Waist circumference was measured in each patient. Patients were questioned about headaches occurring after LP. A total of 115 Quincke-type spinal needles used in 113 patients were evaluated. No deflection was detected in 38 (33.1%) of the needles. Deflection between 0.1° and 5° occurred in 43 (37.3%) of the needles and deflection ≥ 5.1° occurred in 34 patients (29.6%). Forty-seven (41.5%) patients experienced post lumbar puncture headache (PLPH) and 13 (11.5%) patients experienced intracranial hypotension (IH). No statistically significant correlation between the degree of deflection and headache was found (P > 0.05). Epidural blood patch was performed for three patients. Deformity in the form of bending like a hook occurred in seven needles and IH occurred in six patients using these needles. Two of the needles used in three patients requiring blood patch were found to be bent. Deformation of needles may increase complications after LP. Needle deformation may lead to IH. In case of deterioration in the structure of the needle, termination of the puncture procedure and the use of a new needle could reduce undesirable clinical consequences, especially IH.

Comparison of Sample Adequacy and Diagnostic Yield of 19- and 22-G EBUS-TBNA Needles.

PubMed

Chaddha, Udit; Ronaghi, Reza; Elatre, Waafa; Chang, Ching-Fei; Mahdavi, Ramyar

2018-05-16

The 2016 CHEST consensus guidelines recommend use of either 21- or 22-G needles for endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). We decided to prospectively compare sample adequacy and diagnostic yield of the 19-G with the 22-G EBUS needle, hypothesizing that a larger gauge difference might magnify the differences between 2 needle sizes. Twenty-seven patients undergoing EBUS-TBNA at our institution were evaluated. All cases were performed by a single operator formally trained in interventional pulmonology. Both Olympus 19- and 22-G needles were used at each lymph node station in an alternating manner. Rapid on-site cytology evaluation was used and a separate cell block was prepared for each needle at each station. Fifty-six lymph nodes were analyzed. Diagnoses included cancer (36%, including 1 lymphoma), reactive lymphoid tissue (53%), and sarcoidosis (11%). One hundred sixty-two and 163 passes were made with the 22- and 19-G needle, respectively. Sample adequacy was 73% and 46% with the 22 and 19-G needle, respectively (P<0.001). Significantly fewer passes were bloody with the 22-G compared with the 19-G needle (19% vs. 59%; P<0.001). Diagnostic yield was not different between the 22- and 19-G needles (95% vs. 93%; P=0.62). In addition to no difference in diagnostic yield, the 19-G needle yielded samples that were frequently less adequate and more often bloody compared with the 22-G needle. Despite the larger caliber lumen, we conclude that the 19-G needle does not confer a diagnostic advantage.

Broadband Metamaterial for Nonresonant Matching of Acoustic Waves

DTIC Science & Technology

2012-03-28

35898, USA. Unity transmittance at an interface between bulk media is quite common for polarized electromagnetic waves incident at the Brewster angle ...metamaterial possessing a Brewster -like angle that is completely transparent to sound waves over an ultra-broadband frequency range with .100% bandwidth...Unity transmittance at an interface between bulk media is quite common for polarized electromagnetic waves incident at the Brewster angle , but it is

Scattering of Light and Surface Plasmon Polaritons from Rough Surfaces

DTIC Science & Technology

2013-06-14

Scattering of an electromagnetic wave from a slightly random dielectric surface: Yoneda peak and Brewster angle in incoherent scattering.” Waves...device applications. Thus, the negative refraction of a surface plasmon polariton was studied in two papers. In the first [1], all- angle negative... angle of incidence, measured counterclockwise from the negative x1 axis, is . The surface plasmon polariton of frequency transmitted through the

Quantitative evaluation of toothbrush and arm-joint motion during tooth brushing.

PubMed

Inada, Emi; Saitoh, Issei; Yu, Yong; Tomiyama, Daisuke; Murakami, Daisuke; Takemoto, Yoshihiko; Morizono, Ken; Iwasaki, Tomonori; Iwase, Yoko; Yamasaki, Youichi

2015-07-01

It is very difficult for dental professionals to objectively assess tooth brushing skill of patients, because an obvious index to assess the brushing motion of patients has not been established. The purpose of this study was to quantitatively evaluate toothbrush and arm-joint motion during tooth brushing. Tooth brushing motion, performed by dental hygienists for 15 s, was captured using a motion-capture system that continuously calculates the three-dimensional coordinates of object's motion relative to the floor. The dental hygienists performed the tooth brushing on the buccal and palatal sides of their right and left upper molars. The frequencies and power spectra of toothbrush motion and joint angles of the shoulder, elbow, and wrist were calculated and analyzed statistically. The frequency of toothbrush motion was higher on the left side (both buccal and palatal areas) than on the right side. There were no significant differences among joint angle frequencies within each brushing area. The inter- and intra-individual variations of the power spectrum of the elbow flexion angle when brushing were smaller than for any of the other angles. This study quantitatively confirmed that dental hygienists have individual distinctive rhythms during tooth brushing. All arm joints moved synchronously during brushing, and tooth brushing motion was controlled by coordinated movement of the joints. The elbow generated an individual's frequency through a stabilizing movement. The shoulder and wrist control the hand motion, and the elbow generates the cyclic rhythm during tooth brushing.

Does a child's fear of needles decrease through a learning event with needles?

PubMed

Kajikawa, Natsuki; Maeno, Takami; Maeno, Tetsuhiro

2014-09-01

Most children have a fear of needles. Suitable preparation can decrease the pain and fear of needles in hospitals; however, few have examined how such preparation affects healthy children. This study examined whether learning with needles decreases fear of needles and changes motivation to get vaccinations in school-age children and the possible association between fear of needles and motivation toward vaccinations. This study included children participating in the "Let's Be Doctors" event, which was held in 4 child centers in Tsukuba city, Ibaraki, Japan. In this event, children learned about injections and how a vaccine works, and injected a vaccine (water) into skin (sponge) using a real syringe and imitation needle. Data were collected just before and after the event by anonymous self-assessment questionnaires that used a 4-point Likert scale to assess fear of needles, motivation to get vaccinations, recommendation of vaccinations, and fear toward doctors among the children. Answers were divided into two categories for statistical analysis. In total, 194 children participated in the event and 191 children answered the questionnaire (response rate 98.5%). We analyzed 180 subjects, comprising 79 boys (43.9%) and 94 girls (52.2%), mean age of 8.1 ± 1.0 years. The number of children reporting a fear of needles decreased from 69 (38.3%) before the event to 51 (28.3%) after the event, and those unwilling to get vaccinations decreased from 48 (26.7%) to 27 (15.0%). Children who reported fear of needles before the event were more unwilling to get vaccinations than those with no fear of needles (36 [52.2%] vs. 12 [10.8%]), while after the event the number of needle-fearing children unwilling to get vaccinations decreased to 19 (27.5%). Children's fear of needles and unwillingness to get vaccinations were decreased after experiencing a learning event with needles. The fear of needles is associated with a negative motivation to get vaccinations in children.

Subarray-based FDA radar to counteract deceptive ECM signals

NASA Astrophysics Data System (ADS)

Abdalla, Ahmed; Wang, Wen-Qin; Yuan, Zhao; Mohamed, Suhad; Bin, Tang

2016-12-01

In recent years, the frequency diverse array (FDA) radar concept has attracted extensive attention, as it may benefit from a small frequency increment, compared to the carrier frequency across the array elements and thereby achieve an array factor that is a function of the angle, the time, and the range which is superior to the conventional phase array radar (PAR). However, limited effort on the subject of FDA in electronic countermeasure scenarios, especially in the presence of mainbeam deceptive jamming, has been published. Basic FDA is not desirable for anti-jamming applications, due to the range-angle coupling response of targets. In this paper, a novel method based on subarrayed FDA signal processing is proposed to counteract deceptive ECM signals. We divide the FDA array into multiple subarrays, each of which employs a distinct frequency increment. As a result, in the subarray-based FDA, the desired target can be distinguished at subarray level in joint range-angle-Doppler domain by utilizing the fact that the jammer generates false targets with the same ranges to each subarray without reparations. The performance assessment shows that the proposed solution is effective for deceptive ECM targets suppression. The effectiveness is verified by simulation results.

Methods and apparatus for laser beam scanners with different actuating mechanisms

NASA Astrophysics Data System (ADS)

Chen, Si-hai; Xiang, Si-hua; Wu, Xin; Dong, Shan; Xiao, Ding; Zheng, Xia-wei

2009-07-01

In this paper, 3 types of laser beam scanner are introduced. One is transmissive beam scanner, which is composed of convex and concave microlens arrays (MLAs). By moving the concave lens in the plane vertical to the optical axis, the incident beam can be deflected in two dimensions. Those two kinds of MLAs are fabricated by thermal reflow and replication process. A set of mechanical scanner frame is fabricated with the two MLAs assembling in it. The testing result shown that the beam deflection angles are 9.5° and 9.6°, in the 2 dimension(2D) with the scanning frequency of 2 HZ and 8 HZ, respectively. The second type of laser beam scanner is actuated by voice coil actuators (VCAs). Based on ANSOFT MAXWELL software, we have designed VCAs with small size and large force which have optimized properties. The model of VCAs is built using AutoCAD and is analyzed by Ansoft maxwell. According to the simulation results, high performance VCAs are fabricated and tested. The result is that the force of the VCAs is 6.39N/A, and the displacement is +/-2.5mm. A set up of beam scanner is fabricated and actuated by the designed VCAs. The testing result shown that the two dimensional scanning angle is 15° and 10° respectively at the frequency of 60HZ. The two dimensional scanning angle is 8.3° and 6° respectively at the frequency of 100HZ. The third type of scanner is actuated by amplified piezoelectric actuators (APAs). The scanning mirror is actuated by the piezoelectric (PZ) actuators with the scanning frequency of 700HZ, 250HZ and 87HZ respectively. The optical scanning angle is +/-0.5° at the three frequencies.

Pine needle abortion biomarker detected in bovine fetal fluids

USDA-ARS?s Scientific Manuscript database

Pine needle abortion is a naturally occurring condition in free-range cattle caused by the consumption of pine needles from select species of cypress, juniper, pine, and spruce trees. Confirmatory diagnosis of pine needle abortion has previously relied on a combined case history of pine needle cons...

21 CFR 880.5580 - Acupuncture needle.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Acupuncture needle. 880.5580 Section 880.5580 Food... § 880.5580 Acupuncture needle. (a) Identification. An acupuncture needle is a device intended to pierce the skin in the practice of acupuncture. The device consists of a solid, stainless steel needle. The...

Complications after LP related to needle type: pencil-point versus Quincke.

PubMed

Aamodt, A; Vedeler, C

2001-06-01

We studied the incidence of complications after diagnostic lumbar puncture (LP) related to needle type. A 5 months' observational study of routine diagnostic LP in 83 patients was conducted. Significantly more headache was observed after LP using thicker cutting needles (20G Quincke) compared with thinner cutting or non-cutting needles (22G Quincke or pencil-point). No significant difference in complications after LP was found between the 22G Quincke and pencil-point needles. The size of the needle and not the needle shape seems to be the main determinant for post-dural puncture headache (PDPH).

Mixed mode fuel injector with individually moveable needle valve members

DOEpatents

Stewart, Chris; Chockley, Scott A.; Ibrahim, Daniel R.; Lawrence, Keith; Tomaseki, Jay; Azam, Junru H.; Tian, Steven Ye; Shafer, Scott F.

2004-08-03

A fuel injector includes a homogenous charge nozzle outlet set and a conventional nozzle outlet set controlled respectively, by first and second needle valve members. One of the needle valve members moves to an open position while the other needle valve member remains stationary for a homogeneous charge injection event. The former needle valve member stays stationary while the other needle valve member moves to an open position for a conventional injection event. One of the needle valve members is at least partially positioned in the other needle valve member. Thus, the injector can perform homogeneous charge injection events, conventional injection events, or even a mixed mode having both types of injection events in a single engine cycle.

The incidence of coring with blunt versus sharp needles.

PubMed

Wani, Tariq; Wadhwa, Anupama; Tobias, Joseph D

2014-03-01

With the advent of safety needles to prevent inadvertent needle sticks in the operating room (OR), a potentially new issue has arisen. These needles may result in coring, or the shaving off of fragments of the rubber stopper, when the needle is pierced through the rubber stopper of the medication vial. These fragments may be left in the vial and then drawn up with the medication and possibly injected into patients. The current study prospectively evaluated the incidence of coring when blunt and sharp needles were used to pierce rubber topped vials. We also evaluated the incidence of coring in empty medication vials with rubber tops. The rubber caps were then pierced with either an18-gauge sharp hypodermic needle or a blunt plastic (safety) needle. Coring occurred in 102 of 250 (40.8%) vials when a blunt needle was used versus 9 of 215 (4.2%) vials with a sharp needle (P < 0.0001). A significant incidence of coring was demonstrated when a blunt plastic safety needle was used. This situation is potentially a patient safety hazard and methods to eliminate this problem are needed. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of spinal needle characteristics on measurement of spinal canal opening pressure.

PubMed

Bellamkonda, Venkatesh R; Wright, Thomas C; Lohse, Christine M; Keaveny, Virginia R; Funk, Eric C; Olson, Michael D; Laack, Torrey A

2017-05-01

A wide variety of spinal needles are used in clinical practice. Little is currently known regarding the impact of needle length, gauge, and tip type on the needle's ability to measure spinal canal opening pressure. This study aimed to investigate the relationship between these factors and the opening-pressure measurement or time to obtain an opening pressure. Thirteen distinct spinal needles, chosen to isolate the effects of length, gauge, and needle-point type, were prospectively tested on a lumbar puncture simulator. The key outcomes were the opening-pressure measurement and the time required to obtain that measure. Pressures were recorded at 10-s intervals until 3 consecutive, identical readings were observed. Time to measure opening pressure increased with increasing spinal needle length, increasing gauge, and the Quincke-type (cutting) point (P<0.001 for all). The time to measurement ranged from 30s to 530s, yet all needle types were able to obtain a consistent opening pressure measure. Although opening pressure estimates are unlikely to vary markedly by needle type, the time required to obtain the measurement increased with increasing needle length and gauge and with Quincke-type needles. Copyright © 2017 Elsevier Inc. All rights reserved.

Robust path planning for flexible needle insertion using Markov decision processes.

PubMed

Tan, Xiaoyu; Yu, Pengqian; Lim, Kah-Bin; Chui, Chee-Kong

2018-05-11

Flexible needle has the potential to accurately navigate to a treatment region in the least invasive manner. We propose a new planning method using Markov decision processes (MDPs) for flexible needle navigation that can perform robust path planning and steering under the circumstance of complex tissue-needle interactions. This method enhances the robustness of flexible needle steering from three different perspectives. First, the method considers the problem caused by soft tissue deformation. The method then resolves the common needle penetration failure caused by patterns of targets, while the last solution addresses the uncertainty issues in flexible needle motion due to complex and unpredictable tissue-needle interaction. Computer simulation and phantom experimental results show that the proposed method can perform robust planning and generate a secure control policy for flexible needle steering. Compared with a traditional method using MDPs, the proposed method achieves higher accuracy and probability of success in avoiding obstacles under complicated and uncertain tissue-needle interactions. Future work will involve experiment with biological tissue in vivo. The proposed robust path planning method can securely steer flexible needle within soft phantom tissues and achieve high adaptability in computer simulation.

A data-driven soft sensor for needle deflection in heterogeneous tissue using just-in-time modelling.

PubMed

Rossa, Carlos; Lehmann, Thomas; Sloboda, Ronald; Usmani, Nawaid; Tavakoli, Mahdi

2017-08-01

Global modelling has traditionally been the approach taken to estimate needle deflection in soft tissue. In this paper, we propose a new method based on local data-driven modelling of needle deflection. External measurement of needle-tissue interactions is collected from several insertions in ex vivo tissue to form a cloud of data. Inputs to the system are the needle insertion depth, axial rotations, and the forces and torques measured at the needle base by a force sensor. When a new insertion is performed, the just-in-time learning method estimates the model outputs given the current inputs to the needle-tissue system and the historical database. The query is compared to every observation in the database and is given weights according to some similarity criteria. Only a subset of historical data that is most relevant to the query is selected and a local linear model is fit to the selected points to estimate the query output. The model outputs the 3D deflection of the needle tip and the needle insertion force. The proposed approach is validated in ex vivo multilayered biological tissue in different needle insertion scenarios. Experimental results in five different case studies indicate an accuracy in predicting needle deflection of 0.81 and 1.24 mm in the horizontal and vertical lanes, respectively, and an accuracy of 0.5 N in predicting the needle insertion force over 216 needle insertions.

Electromyographic Comparison of Forearm Muscle Movements for Fine Skin Suturing Between an Enlarged Pen Needle Holder and a Webster Needle Holder

PubMed Central

Ohata, Erika; Matsuo, Kiyoshi; Ban, Ryokuya; Shiba, Masato; Yasunaga, Yoshichika

2013-01-01

Background: For surgical suturing, a Webster needle holder uses wrist supinating with supinator and extrinsic muscles, whereas a pen needle holder uses finger twisting with intrinsic and extrinsic muscles. Because the latter is better suited to microsurgery, which requires fine suturing with less forearm muscle movement, we have recently adopted an enlarged pen needle holder scaled from a micro needle holder for fine skin suturing. In this study, we assessed whether the enlarged pen needle holder reduced forearm muscle movement during fine skin suturing as compared with the Webster needle holder. Methods: A fine skin-suturing task was performed using pen holding with the enlarged micro needle holder or scissor holding with the Webster needle holder by 9 experienced and 6 inexperienced microsurgeons. The task lasted for 60 seconds and was randomly performed 3 times for each method. Forearm flexor and extensor muscular activities were evaluated by surface electromyography. Results: The enlarged pen needle holder method required significantly less forearm muscle movement for experienced microsurgeons despite it being their first time using the instrument. There was no significant difference between 2 methods for inexperienced microsurgeons. Conclusions: Experienced microsurgeons conserved forearm muscle movement by finger twisting in fine skin suturing with the enlarged pen needle holder. Inexperienced microsurgeons may benefit from the enlarged pen needle holder, even for fine skin suturing, to develop their internal acquisition model of the dynamics of finger twisting. PMID:23691259

Electromyographic comparison of forearm muscle movements for fine skin suturing between an enlarged pen needle holder and a webster needle holder.

PubMed

Ohata, Erika; Matsuo, Kiyoshi; Ban, Ryokuya; Shiba, Masato; Yasunaga, Yoshichika

2013-01-01

For surgical suturing, a Webster needle holder uses wrist supinating with supinator and extrinsic muscles, whereas a pen needle holder uses finger twisting with intrinsic and extrinsic muscles. Because the latter is better suited to microsurgery, which requires fine suturing with less forearm muscle movement, we have recently adopted an enlarged pen needle holder scaled from a micro needle holder for fine skin suturing. In this study, we assessed whether the enlarged pen needle holder reduced forearm muscle movement during fine skin suturing as compared with the Webster needle holder. A fine skin-suturing task was performed using pen holding with the enlarged micro needle holder or scissor holding with the Webster needle holder by 9 experienced and 6 inexperienced microsurgeons. The task lasted for 60 seconds and was randomly performed 3 times for each method. Forearm flexor and extensor muscular activities were evaluated by surface electromyography. The enlarged pen needle holder method required significantly less forearm muscle movement for experienced microsurgeons despite it being their first time using the instrument. There was no significant difference between 2 methods for inexperienced microsurgeons. Experienced microsurgeons conserved forearm muscle movement by finger twisting in fine skin suturing with the enlarged pen needle holder. Inexperienced microsurgeons may benefit from the enlarged pen needle holder, even for fine skin suturing, to develop their internal acquisition model of the dynamics of finger twisting.

Influence of needle bevel design on injection pain and needle deformation in dental local infiltration anaesthesia - randomized clinical trial.

PubMed

Dau, M; Buttchereit, I; Ganz, C; Frerich, B; Anisimova, E N; Daubländer, M; Kämmerer, P W

2017-11-01

The aims of this in vivo study were to evaluate the impact of needle bevel design on patients' pain perception and the mechanical deformation of the needle tip after the injection. In a prospective single-blinded trial, 150 patients received conventional infiltration anaesthesia for dental treatment by one examiner. Patients were randomized for one out of three different needle bevel types (scalpel-designed bevel needle (SB), n=50; triple bevel needle (TB), n=50; regular bevel needle (RB), n=50). Subjects' self-reported injection pain perception was evaluated using a numeric rating scale (NRS). For each needle tip, deformations after single use were measured using SEM. A significant lower injection pain level was found in SB (mean 2.1±1.2) than in TB (mean 3.5±1.6;) and RB (mean 3.4±1.0; all P<0.001). A needle deformation was detected in about 97.3% of all needles (SB 50/50, TB 50/50, and RB: 46/50). A higher number of barbs were found in SB (29/50) versus TB (17/50) and RB (19/50). For dental local infiltration anaesthesia, injection needles with a scalpel-designed bevel demonstrated significantly less injection pain. Needle tip deflections after anaesthetic agent infiltration, especially barbed hooks on the non-cutting edge may result in greater soft tissue trauma. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Forced Oscillation Wind Tunnel Testing for FASER Flight Research Aircraft

NASA Technical Reports Server (NTRS)

Hoe, Garrison; Owens, Donald B.; Denham, Casey

2012-01-01

As unmanned air vehicles (UAVs) continue to expand their flight envelopes into areas of high angular rate and high angle of attack, modeling the complex unsteady aerodynamics for simulation in these regimes has become more difficult using traditional methods. The goal of this experiment was to improve the current six degree-of-freedom aerodynamic model of a small UAV by replacing the analytically derived damping derivatives with experimentally derived values. The UAV is named the Free-flying Aircraft for Sub-scale Experimental Research, FASER, and was tested in the NASA Langley Research Center 12- Foot Low-Speed Tunnel. The forced oscillation wind tunnel test technique was used to measure damping in the roll and yaw axes. By imparting a variety of sinusoidal motions, the effects of non-dimensional angular rate and reduced frequency were examined over a large range of angle of attack and side-slip combinations. Tests were performed at angles of attack from -5 to 40 degrees, sideslip angles of -30 to 30 degrees, oscillation amplitudes from 5 to 30 degrees, and reduced frequencies from 0.010 to 0.133. Additionally, the effect of aileron or elevator deflection on the damping coefficients was examined. Comparisons are made of two different data reduction methods used to obtain the damping derivatives. The results show that the damping derivatives are mainly a function of angle of attack and have dependence on the non-dimensional rate and reduced frequency only in the stall/post-stall regime