Endoventricular Deep Brain Stimulation of the Third Ventricle: Proof of Concept and Application to Cluster Headache.

PubMed

Chabardès, Stéphan; Carron, Romain; Seigneuret, Eric; Torres, Napoleon; Goetz, Laurent; Krainik, Alexandre; Piallat, Brigitte; Pham, Pascale; David, Olivier; Giraud, Pierrick; Benabid, Alim Louis

2016-12-01

The third ventricle (3rd V) is surrounded by centers related to satiety, homeostasis, hormones, sleep, memory, and pain. Stimulation of the wall of the 3rd V could be useful to treat disorders related to dysfunction of the hypothalamus. To assess safety and efficacy of endoventricular electrical stimulation of the hypothalamus using a floating deep brain stimulation (DBS) lead laid on the floor of the 3rd V to treat refractory cluster headaches (CH). Seven patients, aged 24 to 60 years, experiencing chronic CH (mean chronic duration 5.8 ± 2.5 years) were enrolled in this pilot, prospective, open study assessing the safety and potential efficacy of chronic DBS of the 3rd V. Number of attacks was collected during baseline and was compared with those occurring at 3, 6, and 12 months postoperation. Any side effects that occurred during or after surgery were reported. Effect on mood was assessed using the Hospital Anxiety and Depression scale during baseline and at 6 and 12 months postoperation. Insertion of the lead into the posterior 3rd V and chronic stimulation was feasible and safe in all patients. The voltage ranged from 0.9 to 2.3 volts. The most common side effect was transient trembling vision during stimulation. At 12 months, 3 of 7 patients were pain free, 2 had 90% improvement, 1 of 7 had 75% improvement, and 1 of 7 was not significantly improved. This proof of concept demonstrates the feasibility, safety, and potential efficacy of 3rd V DBS using an endoventricular road that could be applied to treat various diseases involving hypothalamic areas. CCH, chronic cluster headacheCH, cluster headacheDBS, deep brain stimulationHAD, hospital anxiety depressionONS, occipital nerve stimulationPAG, periaqueductal gray matterPH, posterior hypothalamusPVG, periventricular gray matter3rd V, third ventricle.

Effects of finite ground plane on the radiation characteristics of a circular patch antenna

NASA Astrophysics Data System (ADS)

Bhattacharyya, Arun K.

1990-02-01

An analytical technique to determine the effects of finite ground plane on the radiation characteristics of a microstrip antenna is presented. The induced currents on the ground plane and on the upper surface of the patch are determined from the discontinuity of the near field produced by the equivalent magnetic current source on the physical aperture of the patch. The radiated fields contributed by the induced current on the ground plane and the equivalent sources on the physical aperture yield the radiation pattern of the antenna. Radiation patterns of the circular patch with finite ground plane size are computed and compared with the experimental data, and the agreement is found to be good. The radiation pattern, directive gain, and input impedance are found to vary widely with the ground plane size.

The 20 GHz circularly polarized, high temperature superconducting microstrip antenna array

NASA Technical Reports Server (NTRS)

Morrow, Jarrett D.; Williams, Jeffery T.; Long, Stuart A.; Wolfe, John C.

1994-01-01

The primary goal was to design and characterize a four-element, 20 GHz, circularly polarized microstrip patch antenna fabricated from YBa2Cu3O(x) superconductor. The purpose is to support a high temperature superconductivity flight communications experiment between the space shuttle orbiter and the ACTS satellite. This study is intended to provide information into the design, construction, and feasibility of a circularly polarized superconducting 20 GHz downlink or cross-link antenna. We have demonstrated that significant gain improvements can be realized by using superconducting materials for large corporate fed array antennas. In addition, we have shown that when constructed from superconducting materials, the efficiency, and therefore the gain, of microstrip patches increases if the substrate is not so thick that the dominant loss mechanism for the patch is radiation into the surface waves of the conductor-backed substrate. We have considered two design configurations for a superconducting 20 GHz four-element circularly polarized microstrip antenna array. The first is the Huang array that uses properly oriented and phased linearly polarized microstrip patch elements to realize a circularly polarized pattern. The second is a gap-coupled array of circularly polarized elements. In this study we determined that although the Huang array operates well on low dielectric constant substrates, its performance becomes extremely sensitive to mismatches, interelement coupling, and design imperfections for substrates with high dielectric constants. For the gap-coupled microstrip array, we were able to fabricate and test circularly polarized elements and four-element arrays on LaAlO3 using sputtered copper films. These antennas were found to perform well, with relatively good circular polarization. In addition, we realized a four-element YBa2Cu3O(x) array of the same design and measured its pattern and gain relative to a room temperature copper array. The patterns were essentially the same as that for the copper array. The measured gain of the YBCO antenna was greater than that for the room temperature copper design at temperatures below 82K, reaching a value of 3.4 dB at the lowest temperatures.

A 10 GHz Y-Ba-Cu-O/GaAs hybrid oscillator proximity coupled to a circular microstrip patch antenna

NASA Technical Reports Server (NTRS)

Rohrer, Norman J.; Richard, M. A.; Valco, George J.; Bhasin, Kul B.

1993-01-01

A 10 GHz hybrid YBCO/GaAs microwave oscillator proximity coupled to a circular microstrip antenna has been designed, fabricated, and characterized. The oscillator was a reflection mode type using a GaAs MESFET as the active element. The feedline, transmission lines, RF chokes, and bias lines were all fabricated from YBCO superconducting thin films on a 1 cm x 1 cm lanthanum aluminate substrate. The output feedline of the oscillator was wire bonded to a superconducting feedline on a second 1 cm x 1 cm lanthanum aluminate substrate, which was in turn proximity coupled to a circular microstrip patch antenna. Antenna patterns from this active patch antenna and the performance of the oscillator measured at 77 K are reported. The oscillator had a maximum output power of 11.5 dBm at 77 K, which corresponded to an efficiency of 10 percent. In addition, the efficiency of the microstrip patch antenna together with its high temperature superconducting feedline was measured from 85 K to 30 K and was found to be 71 percent at 77 K, increasing to a maximum of 87.4 percent at 30 K.

Circularly Polarized S Band Dual Frequency Square Patch Antenna Using Glass Microfiber Reinforced PTFE Composite

PubMed Central

Samsuzzaman, M.; Islam, M. T.; Arshad, Haslina; Mandeep, J. S.; Misran, N.

2014-01-01

Circularly polarized (CP) dual frequency cross-shaped slotted patch antenna on 1.575 mm thick glass microfiber reinforced polytetrafluoroethylene (PTFE) composite material substrate is designed and fabricated for satellite applications. Asymmetric cross-shaped slots are embedded in the middle of the square patch for CP radiation and four hexagonal slots are etched on the four sides of the square patch for desired dual frequency. Different substrate materials have been analysed to achieve the desired operating band. The experimental results show that the impedance bandwidth is approximately 30 MHz (2.16 GHz to 2.19 GHz) for lower band and 40 MHz (3.29 GHz to 3.33 GHz) for higher band with an average peak gain of 6.59 dBiC and 5.52 dBiC, respectively. Several optimizations are performed to obtain the values of the antenna physical parameters. Moreover, the proposed antenna possesses compactness, light weight, simplicity, low cost, and circularly polarized. It is an attractive candidate for dual band satellite antennas where lower band can be used for uplink and upper band can be used for downlink. PMID:24982943

A 10 GHz Y-Ba-Cu-O/GaAs hybrid oscillator proximity coupled to a circular microstrip patch antenna

NASA Technical Reports Server (NTRS)

Rohrer, Norman J.; Richard, M. A.; Valco, George J.; Bhasin, Kul B.

1993-01-01

A 10 GHz hybrid Y-Ba-Cu-O / GaAs microwave oscillator proximity coupled to a circular microstrip antenna was designed, fabricated and characterized. The oscillator was a reflection mode type using a GaAs MESFET as the active element. The feedline, transmission lines, RF chokes, and bias lines were all fabricated from YBa2Cu3O(7-x) superconducting thin films on a 1 cm x 1 cm lanthanum aluminate substrate. The output feedline of the oscillator was wire bonded to a superconducting feedline on a second 1 cm x 1 cm lanthanum aluminate substrate, which was in turn proximity coupled to a circular microstrip patch antenna. Antenna patterns from this active patch antenna and the performance of the oscillator measured at 77 K are reported. The oscillator had a maximum output power of 11.5 dBm at 77 K, which corresponded to an efficiency of 10 percent. In addition, the efficiency of the microstrip patch antenna together with its high temperature superconducting feedline was measured from 85 K to 30 K and was found to be 71 percent at 77 4 increasing to a maximum of 87.4 percent at 30 K.

Microelectromechanical Systems Actuator Based Reconfigurable Printed Antenna

NASA Technical Reports Server (NTRS)

Simons, Rainee N. (Inventor)

2005-01-01

A polarization reconfigurable patch antenna is disclosed. The antenna includes a feed element, a patch antenna element electrically connected to the feed element, and at least one microelectromechanical systems (MEMS) actuator, with a partial connection to the patch antenna element along an edge of the patch antenna element. The polarization of the antenna can be switched between circular polarization and linear polarization through action of the at least one MEMS actuator.

Superstrate loading effects on the resonant characteristics of high Tc superconducting circular patch printed on anisotropic materials

NASA Astrophysics Data System (ADS)

Bedra, Sami; Bedra, Randa; Benkouda, Siham; Fortaki, Tarek

2017-12-01

In this paper, the effects of both anisotropies in the substrate and superstrate loading on the resonant frequency and bandwidth of high-Tc superconducting circular microstrip patch in a substrate-superstrate configuration are investigated. A rigorous analysis is performed using a dyadic Galerkin's method in the vector Hankel transform domain. Galerkin's procedure is employed in the spectral domain where the TM and TE modes of the cylindrical cavity with magnetic side walls are used in the expansion of the disk current. The effect of the superconductivity of the patch is taken into account using the concept of the complex resistive boundary condition. London's equations and the two-fluid model of Gorter and Casimir are used in the calculation of the complex surface impedance of the superconducting circular disc. The accuracy of the analysis is tested by comparing the computed results with previously published data for several anisotropic substrate-superstrate materials. Good agreement is found among all sets of results. The numerical results obtained show that important errors can be made in the computation of the resonant frequencies and bandwidths of the superconducting resonators when substrate dielectric anisotropy, and/or superstrate anisotropy are ignored. Other theoretical results obtained show that the superconducting circular microstrip patch on anisotropic substrate-superstrate with properly selected permittivity values along the optical and the non-optical axes combined with optimally chosen structural parameters is more advantageous than the one on isotropic substrate-superstrate by exhibiting wider bandwidth characteristic.

A novel one-shot circular stapler closure for atrial septal defect in a beating-heart porcine model.

PubMed

Tarui, Tatsuya; Tomita, Shigeyuki; Ishikawa, Norihiko; Ohtake, Hiroshi; Watanabe, Go

2015-02-01

In surgical atrial septal defect (ASD) closure, there are no techniques or devices that can close the ASD accurately in a short time under a beating heart. We have developed a simple and automatic ASD closure technique using a circular stapler. This study assessed the feasibility and efficacy of a new circular stapler closure for ASD. Under a continuous beating heart, hand-sewn patch plasty ASD closure was performed in 6 pigs (group A) and circular stapler ASD closure was performed in 6 pigs (group B). The time to close the ASD and the effectiveness of the closure were compared. Closure was significantly faster in group B (10.5 ± 1.0 seconds) than in group A (664 ± 10 seconds; p < 0.05). There was no leakage at the closure site, and sufficient tolerance was confirmed. A circular stapler can be used to treat ASD faster than hand-sewn patch plasty, with sufficient pressure tolerance in a beating heart porcine model. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Stripline feed for a microstrip array of patch elements with teardrop shaped probes

NASA Technical Reports Server (NTRS)

Huang, John (Inventor)

1990-01-01

A circularly polarized microstrip array antenna utilizing a honeycomb substrate made of dielectric material to support on one side the microstrip patch elements in an array, and on the other side a stripline circuit for feeding the patch elements in subarray groups of four with angular orientation and phase for producing circularly polarized radiation, preferably at a 0.degree., 90.degree., 180.degree. and 270.degree. relationship. The probe used for coupling each feed point in the stripline circuit to a microstrip patch element is teardrop shaped in order to introduce capacitance between the coupling probe and the metal sheet of the stripline circuit that serves as an antenna ground plane. The capacitance thus introduced tunes out inductance of the probe. The shape of the teardrop probe is not critical. The probe capacitance required is controlled by the maximum diameter for the teardrop shaped probe, which can be empirically determined for the operating frequency. An aluminum baffle around each subarray blocks out surface waves between subarrays.

Broadbanding of circularly polarized patch antenna by waveguided magneto-dielectric metamaterial

NASA Astrophysics Data System (ADS)

Yang, Xin Mi; Wen, Juan; Liu, Chang Rong; Liu, Xue Guan; Cui, Tie Jun

2015-12-01

Design of bandwidth-enhanced circularly polarized (CP) patch antenna using artificial magneto-dielectric substrate was investigated. The artificial magneto-dielectric material adopted here takes the form of waveguided metamaterial (WG-MTM). In particular, the embedded meander line (EML) structure was employed as the building element of the WG-MTM. As verified by the retrieved effective medium parameters, the EML-based waveguided magneto-dielectric metamaterial (WG-MDM) exhibits two-dimensionally isotropic magneto-dielectric property with respect to TEM wave excitations applied in two orthogonal directions. A CP patch antenna loaded with the EML-based WG-MDM (WG-MDM antenna) has been proposed and its design procedure is described in detail. Simulation results show that the impedance and axial ratio bandwidths of the WG-MDM antenna have increased by 125% and 133%, respectively, compared with those obtained with pure dielectric substrate offering the same patch size. The design of the novel WG-MDM antenna was also validated by measurement results, which show good agreement with their simulated counterparts.

EBG Based Microstrip Patch Antenna for Brain Tumor Detection via Scattering Parameters in Microwave Imaging System.

PubMed

Inum, Reefat; Rana, Md Masud; Shushama, Kamrun Nahar; Quader, Md Anwarul

2018-01-01

A microwave brain imaging system model is envisaged to detect and visualize tumor inside the human brain. A compact and efficient microstrip patch antenna is used in the imaging technique to transmit equivalent signal and receive backscattering signal from the stratified human head model. Electromagnetic band gap (EBG) structure is incorporated on the antenna ground plane to enhance the performance. Rectangular and circular EBG structures are proposed to investigate the antenna performance. Incorporation of circular EBG on the antenna ground plane provides an improvement of 22.77% in return loss, 5.84% in impedance bandwidth, and 16.53% in antenna gain with respect to the patch antenna with rectangular EBG. The simulation results obtained from CST are compared to those obtained from HFSS to validate the design. Specific absorption rate (SAR) of the modeled head tissue for the proposed antenna is determined. Different SAR values are compared with the established standard SAR limit to provide a safety regulation of the imaging system. A monostatic radar-based confocal microwave imaging algorithm is applied to generate the image of tumor inside a six-layer human head phantom model. S -parameter signals obtained from circular EBG loaded patch antenna in different scanning modes are utilized in the imaging algorithm to effectively produce a high-resolution image which reliably indicates the presence of tumor inside human brain.

EBG Based Microstrip Patch Antenna for Brain Tumor Detection via Scattering Parameters in Microwave Imaging System

PubMed Central

Rana, Md. Masud; Shushama, Kamrun Nahar; Quader, Md. Anwarul

2018-01-01

A microwave brain imaging system model is envisaged to detect and visualize tumor inside the human brain. A compact and efficient microstrip patch antenna is used in the imaging technique to transmit equivalent signal and receive backscattering signal from the stratified human head model. Electromagnetic band gap (EBG) structure is incorporated on the antenna ground plane to enhance the performance. Rectangular and circular EBG structures are proposed to investigate the antenna performance. Incorporation of circular EBG on the antenna ground plane provides an improvement of 22.77% in return loss, 5.84% in impedance bandwidth, and 16.53% in antenna gain with respect to the patch antenna with rectangular EBG. The simulation results obtained from CST are compared to those obtained from HFSS to validate the design. Specific absorption rate (SAR) of the modeled head tissue for the proposed antenna is determined. Different SAR values are compared with the established standard SAR limit to provide a safety regulation of the imaging system. A monostatic radar-based confocal microwave imaging algorithm is applied to generate the image of tumor inside a six-layer human head phantom model. S-parameter signals obtained from circular EBG loaded patch antenna in different scanning modes are utilized in the imaging algorithm to effectively produce a high-resolution image which reliably indicates the presence of tumor inside human brain. PMID:29623087

Multiport Circular Polarized RFID-Tag Antenna for UHF Sensor Applications.

PubMed

Zaid, Jamal; Abdulhadi, Abdulhadi; Kesavan, Arun; Belaizi, Yassin; Denidni, Tayeb A

2017-07-05

A circular polarized patch antenna for UHF RFID tag-based sensor applications is presented, with the circular polarization (CP) generated by a new antenna shape, an asymmetric stars shaped slotted microstrip patch antenna (CP-ASSSMP). Four stars etched on the patch allow the antenna's size to be reduced by close to 20%. The proposed antenna is matched with two RFID chips via inductive-loop matching. The first chip is connected to a resistive sensor and acts as a sensor node, and the second is used as a reference node. The proposed antenna is used for two targets, serving as both reference and sensor simultaneously, thereby eliminating the need for a second antenna. Its reader can read the RFID chips at any orientation of the tag due to the CP. The measured reading range is about 25 m with mismatch polarization. The operating frequency band is 902-929 MHz for the two ports, which is covered by the US RFID band, and the axial-ratio bandwidth is about 7 MHz. In addition, the reader can also detect temperature, based on the minimum difference in the power required by the reference and sensor.

Multiport Circular Polarized RFID-Tag Antenna for UHF Sensor Applications

PubMed Central

Zaid, Jamal; Abdulhadi, Abdulhadi; Kesavan, Arun; Belaizi, Yassin; Denidni, Tayeb A.

2017-01-01

A circular polarized patch antenna for UHF RFID tag-based sensor applications is presented, with the circular polarization (CP) generated by a new antenna shape, an asymmetric stars shaped slotted microstrip patch antenna (CP-ASSSMP). Four stars etched on the patch allow the antenna’s size to be reduced by close to 20%. The proposed antenna is matched with two RFID chips via inductive-loop matching. The first chip is connected to a resistive sensor and acts as a sensor node, and the second is used as a reference node. The proposed antenna is used for two targets, serving as both reference and sensor simultaneously, thereby eliminating the need for a second antenna. Its reader can read the RFID chips at any orientation of the tag due to the CP. The measured reading range is about 25 m with mismatch polarization. The operating frequency band is 902–929 MHz for the two ports, which is covered by the US RFID band, and the axial-ratio bandwidth is about 7 MHz. In addition, the reader can also detect temperature, based on the minimum difference in the power required by the reference and sensor. PMID:28678178

Design of metamirrors for linear to circular polarization conversion with super-octave bandwidth

NASA Astrophysics Data System (ADS)

Fartookzadeh, Mahdi

2017-10-01

In this paper, bandwidth improvement of reflection-mode linear to circular polarization converters (RMCPs) is studied. The proposed RMCP is based on multi-layer rectangular patches. Equivalent transmission line circuit of multi-layer reflection-mode polarization converters is used for designing the proposed metamirror. In addition, the approximate equation of axial ratio (AR) of the reflected wave is obtained from the structures containing rectangular patches on each layer. Polarization converters containing multi-layer rectangular patches can be utilized for different ranges of frequencies. However, the frequency range of 2-8 THz is considered in this paper without losing generality. The incident wave is assumed to be linearly polarized with 45° polarization angle. AR equation is used for initial optimization of the dimensions of rectangular patches to obtain the widest possible bandwidth of RMCPs with two- and three-layer patches. Secondary optimization is applied after specifying largest dimensions of the unit cell and excluding them from the variables of optimization. Finally, modified dimensions of the three-layer RMCP are obtained using parametrical study in simulations. The proposed three-layer polarization converter has the 3 dB axial ratio bandwidth of more than 116% and the permitted incident angle of higher than 25°.

Electromagnetic scattering and radiation from microstrip patch antennas and spirals residing in a cavity

NASA Technical Reports Server (NTRS)

Volakis, J. L.; Gong, J.; Alexanian, A.; Woo, A.

1992-01-01

A new hybrid method is presented for the analysis of the scattering and radiation by conformal antennas and arrays comprised of circular or rectangular elements. In addition, calculations for cavity-backed spiral antennas are given. The method employs a finite element formulation within the cavity and the boundary integral (exact boundary condition) for terminating the mesh. By virtue of the finite element discretization, the method has no restrictions on the geometry and composition of the cavity or its termination. Furthermore, because of the convolutional nature of the boundary integral and the inherent sparseness of the finite element matrix, the storage requirement is kept very low at O(n). These unique features of the method have already been exploited in other scattering applications and have permitted the analysis of large-size structures with remarkable efficiency. In this report, we describe the method's formulation and implementation for circular and rectangular patch antennas in different superstrate and substrate configurations which may also include the presence of lumped loads and resistive sheets/cards. Also, various modelling approaches are investigated and implemented for characterizing a variety of feed structures to permit the computation of the input impedance and radiation pattern. Many computational examples for rectangular and circular patch configurations are presented which demonstrate the method's versatility, modeling capability and accuracy.

A Circular Microstrip Antenna Sensor for Direction Sensitive Strain Evaluation.

PubMed

Lopato, Przemyslaw; Herbko, Michal

2018-01-20

In this paper, a circular microstrip antenna for stress evaluation is studied. This kind of microstrip sensor can be utilized in structural health monitoring systems. Reflection coefficient S 11 is measured to determine deformation/strain value. The proposed sensor is adhesively connected to the studied sample. Applied strain causes a change in patch geometry and influences current distribution both in patch and ground plane. Changing the current flow in patch influences the value of resonant frequency. In this paper, two different resonant frequencies were analysed because in each case, different current distributions in patch were obtained. The sensor was designed for operating frequency of 2.5 GHz (at fundamental mode), which results in a diameter less than 55 mm. Obtained sensitivity was up to 1 MHz/100 MPa, resolution depends on utilized vector network analyser. Moreover, the directional characteristics for both resonant frequencies were defined, studied using numerical model and verified by measurements. Thus far, microstrip antennas have been used in deformation measurement only if the direction of external force was well known. Obtained directional characteristics of the sensor allow the determination of direction and value of stress by one sensor. This method of measurement can be an alternative to the rosette strain gauge.

Quadrature transmit array design using single-feed circularly polarized patch antenna for parallel transmission in MR imaging.

PubMed

Pang, Yong; Yu, Baiying; Vigneron, Daniel B; Zhang, Xiaoliang

2014-02-01

Quadrature coils are often desired in MR applications because they can improve MR sensitivity and also reduce excitation power. In this work, we propose, for the first time, a quadrature array design strategy for parallel transmission at 298 MHz using single-feed circularly polarized (CP) patch antenna technique. Each array element is a nearly square ring microstrip antenna and is fed at a point on the diagonal of the antenna to generate quadrature magnetic fields. Compared with conventional quadrature coils, the single-feed structure is much simple and compact, making the quadrature coil array design practical. Numerical simulations demonstrate that the decoupling between elements is better than -35 dB for all the elements and the RF fields are homogeneous with deep penetration and quadrature behavior in the area of interest. Bloch equation simulation is also performed to simulate the excitation procedure by using an 8-element quadrature planar patch array to demonstrate its feasibility in parallel transmission at the ultrahigh field of 7 Tesla.

Circularly polarized triple band glass shaped monopole patch antenna with metallic reflector for bluetooth & wireless applications

NASA Astrophysics Data System (ADS)

Jangid, K. G.; Choudhary, N.; Jain, P.; Sharma, B. R.; Saini, J. S.; Kulhar, V. S.; Bhatnagar, D.

2016-03-01

This paper presents the design and performance of strip line fed glass shaped monopole patch antenna having with overall size 30mm × 30 mm × 1.59 mm. In the patch; an eight shaped slot and in the ground plane an eight shaped ring are introduced. A metallic ground plane is also introduced at appropriate location beneath the ground plane. The proposed antenna is simulated by applying CST Microwave Studio simulator. Antenna provides circularly polarized radiations, triple broad impedance bandwidth of 203MHz (2.306GHz to 2.510GHz), 42MHz (2.685GHz to 2.757GHz) & GHz (3.63 GHz to 6.05 GHz), high flat gain (close to 5dBi) and good radiation properties in the desired frequency range. This antenna may be a very useful tool for 2.45GHz Bluetooth communication band as well as for 2.4GHz/5.2 GHz /5.8 GHz WLAN bands & 3.7GHz/5.5 GHz Wi-Max bands.

A new shape for an old function: lasting effect of a physiologic surgical restoration of the left ventricle

PubMed Central

Cirillo, Marco; Amaducci, Andrea; Villa, Emmanuel; Tomba, Margherita Dalla; Brunelli, Federico; Mhagna, Zen; Troise, Giovanni; Quaini, Eugenio

2006-01-01

Background Long-term morphofunctional outcome may vary widely in surgical anterior left ventricular wall restoration, suggesting variability in post-surgical remodeling similar to that observed following acute myocardial infarction. The aim of this pilot study was to demonstrate that surgical restoration obtained with a particular shape of endoventricular patch leads to steady morphofunctional ventricular improvement when geometry, volume and residual akinesia can be restored as normal as possible. Methods This study involved 12 consecutive patients with previous anterior myocardial infarction, dilated cardiomyopathy and no mitral procedures, who underwent left ventricular reconstruction and coronary revascularization between May 2002 and May 2003 using a small, narrow, oval patch aiming at a volume ≤ 45 mL/m2 with elliptical shape. Eleven geometric parameters were examined preoperatively and at least 3, 12 and 24 months after the operation by serial echocardiographic studies and evaluated by paired t test taking the time of surgery as a starting point for remodeling. Results All patients were in NYHA class 1 at follow-up. Patch geometry obtained a conical shape of the ventricle with new apex, physiologic rearrangement of functioning myocardial wall and small residual akinesia. Ventricular changes at the four time-points showed that all parameters improved significantly compared to preoperative values (end-diastolic volume = 184.2 ± 23.9 vs 139.9 ± 22.0, p = 0.001; vs 151.0 ± 33.8, p = 0.06; vs 144.9 ± 34.0, p = 0.38; end-systolic volume = 125.7 ± 20.6 vs 75.2 ± 14.1, p = 0.001; vs 82.1 ± 23.9, p = 0,18; vs 77.1 ± 19.4, p = 0.41) without further changes during follow-up except for wall motion score index (2.0 ± 0.2 to 1.7 ± 0.2, to 1.4 ± 0.2, to 1.3 ± 0.2) and percentage of akinesia (30.4 ± 7.5 to 29.3 ± 4.2, to 19.8 ± 11.6, to 14.5 ± 7.2) which slowly and significantly improved suggesting a positive post-surgery remodeling. Conclusion Ventricular reconstruction caring of physiological shape, volume, revascularization and residual akinesia obtained a steady geometry. Positive remodeling and equalization of geometrical outcome may persistently prevent long-term redilation. PMID:17083734

A Circular Microstrip Antenna Sensor for Direction Sensitive Strain Evaluation †

PubMed Central

Herbko, Michal

2018-01-01

In this paper, a circular microstrip antenna for stress evaluation is studied. This kind of microstrip sensor can be utilized in structural health monitoring systems. Reflection coefficient S11 is measured to determine deformation/strain value. The proposed sensor is adhesively connected to the studied sample. Applied strain causes a change in patch geometry and influences current distribution both in patch and ground plane. Changing the current flow in patch influences the value of resonant frequency. In this paper, two different resonant frequencies were analysed because in each case, different current distributions in patch were obtained. The sensor was designed for operating frequency of 2.5 GHz (at fundamental mode), which results in a diameter less than 55 mm. Obtained sensitivity was up to 1 MHz/100 MPa, resolution depends on utilized vector network analyser. Moreover, the directional characteristics for both resonant frequencies were defined, studied using numerical model and verified by measurements. Thus far, microstrip antennas have been used in deformation measurement only if the direction of external force was well known. Obtained directional characteristics of the sensor allow the determination of direction and value of stress by one sensor. This method of measurement can be an alternative to the rosette strain gauge. PMID:29361697

Circularly polarized triple band glass shaped monopole patch antenna with metallic reflector for bluetooth & wireless applications

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

Jangid, K. G.; Kulhar, V. S.; Choudhary, N.

This paper presents the design and performance of strip line fed glass shaped monopole patch antenna having with overall size 30mm × 30 mm × 1.59 mm. In the patch; an eight shaped slot and in the ground plane an eight shaped ring are introduced. A metallic ground plane is also introduced at appropriate location beneath the ground plane. The proposed antenna is simulated by applying CST Microwave Studio simulator. Antenna provides circularly polarized radiations, triple broad impedance bandwidth of 203MHz (2.306GHz to 2.510GHz), 42MHz (2.685GHz to 2.757GHz) & GHz (3.63 GHz to 6.05 GHz), high flat gain (close to 5dBi) and good radiationmore » properties in the desired frequency range. This antenna may be a very useful tool for 2.45GHz Bluetooth communication band as well as for 2.4GHz/5.2 GHz /5.8 GHz WLAN bands & 3.7GHz/5.5 GHz Wi-Max bands.« less

A Low-Profile Dual-Layer Patch Antenna with a Circular Polarizer Consisting of Dual Semicircular Resonators.

PubMed

Guo, Li; Tang, Ming-Chun; Li, Mei

2018-06-01

In this paper, a circular polarizer comprising dual semicircular split-rings (DSSRs) is presented. By placing it above an elliptical radiator that radiates linearly polarized (LP) waves, dual-layer patch antennas capable of radiating right-hand (RH) or left-hand (LH) circularly polarized (CP) waves are achieved in terms of the different offset direction of the bottom splits of the DSSRs. Because of both the capacitive coupling to the radiator and the degenerate modes existing in the excited DSSRs, the DSSRs collaboratively result in a circularly polarized radiation, successfully converting incident LP waves into CP ones. Simulated results show that the impedance, axial ratio (AR), and gain frequency response of both proposed CP antennas are identical, with a simulated 3-dB AR bandwidth of 72 MHz covering 2.402⁻2.474 GHz and a gain enhanced by 3.9 dB. The proposed antennas were fabricated and measured, revealing an operational bandwidth of 65 MHz (2.345⁻2.41 GHz) and a peak gain up to 9 dBi. Moreover, a low profile of 0.063λ₀ is maintained. The proposed CP antennas could be as a candidate for wireless target detection applications in terms of their identical frequency response property.

Microstrip antenna developments at JPL

NASA Technical Reports Server (NTRS)

Huang, John

1991-01-01

The in-house development of microstrip antennas, initiated in 1981, when a spaceborne lightweight and low-profile planar array was needed for a satellite communication system, is described. The work described covers the prediction of finite-ground-plane effects by the geometric theory of diffraction, higher-order-mode circularly polarized circular patch antennas, circularly polarized microstrip arrays with linearly polarized elements, an impedance-matching teardrop-shaped probe feed, a dual-polarized microstrip array with high isolation and low cross-polarization, a planar microstrip Yagi array, a microstrip reflectarray, a Ka-band MMIC array, and a series-fed linear arrays.

Multilayer Patch Antenna Surrounded by a Metallic Wall

NASA Technical Reports Server (NTRS)

Zawadzki, Mark; Huang, John

2003-01-01

A multilayer patch antenna, similar to a Yagi antenna, surrounded by a metallic wall has been devised to satisfy requirements to fit within a specified size and shape and to generate a beam with a half-power angular width of <=40 deg. This antenna provides a gain of about 14 dB; in contrast, the gain of a typical single-patch antenna lies between 5 and 6 dB. This antenna can be considered an alternative to a two-dimensional array of patch antenna elements, or to a horn or helical antenna. Unlike a two-dimensional array of patches, this antenna can function without need for a power-division network (unless circular polarization is needed). The profile of this antenna is lower than that of a horn or a helical antenna designed for the same frequency. The primary disadvantage of this antenna, relative to a horn or a helical antenna, is that its footprint is slightly larger.

Miniaturized printed K shaped monopole antenna with truncated ground plane for 2.4/5.2/5.5/5.8 wireless lan applications

NASA Astrophysics Data System (ADS)

Chandan, Bharti, Gagandeep; Srivastava, Toolika; Rai, B. S.

2018-04-01

A novel truncated ground plane monopole antenna is proposed for wide band wireless local area network (WLAN) applications. The antenna contains a rectangular patch with a rectangular ring, a circular slot and a truncated ground plane printed on opposite sides of a low cost substrate FR4. The operating frequency bands for the antenna are band1 (2.4-2.88 GHz) and band 2 (4.8-6.3 GHz) with ≤ - 10 dB return loss which covers 2.4/5.2/5.5/5.8 GHz WLAN bands. The antenna is compact with overall dimension 26×40×0.8 mmł and with the dimension of patch 16×16×0.8 mm3. The two bands of antenna is obtained by cutting a rectangular ring and a circular slot in the patch and return loss is improved by cutting two rectangular slot in the ground plane. Performance measures of the antenna are shown in terms of return loss, current distribution, radiation pattern and gain. To verify the simulated results, the antenna is also fabricated and tested. The simulated and fabricated results have been found in good agreement.

Planar microstrip YAGI antenna array

NASA Technical Reports Server (NTRS)

Huang, John (Inventor)

1993-01-01

A directional microstrip antenna includes a driven patch surrounded by an isolated reflector and one or more coplanar directors, all separated from a ground plane on the order of 0.1 wavelength or less to provide end fire beam directivity without requiring power dividers or phase shifters. The antenna may be driven at a feed point a distance from the center of the driven patch in accordance with conventional microstrip antenna design practices for H-plane coupled or horizontally polarized signals. The feed point for E-plane coupled or vertically polarized signals is at a greater distance from the center than the first distance. This feed point is also used for one of the feed signals for circularly polarized signals. The phase shift between signals applied to feed points for circularly polarized signals must be greater than the conventionally required 90 degrees and depends upon the antenna configuration.

Simulation of thin slot spirals and dual circular patch antennas using the finite element method with mixed elements

NASA Technical Reports Server (NTRS)

Gong, Jian; Volakis, John L.; Nurnberger, Michael W.

1995-01-01

This semi-annual report describes progress up to mid-January 1995. The report contains five sections all dealing with the modeling of spiral and patch antennas recessed in metallic platforms. Of significance is the development of decomposition schemes which separate the different regions of the antenna volume. Substantial effort was devoted to improving the feed model in the context of the finite element method (FEM). Finally, an innovative scheme for truncating finite element meshes is presented.

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.

Results of transcatheter pulmonary valvulation in native or patched right ventricular outflow tracts.

PubMed

Malekzadeh-Milani, Sophie; Ladouceur, Magalie; Cohen, Sarah; Iserin, Laurence; Boudjemline, Younes

2014-11-01

Although widely accepted worldwide, indications for percutaneous valve replacement are limited to treatment of dysfunction of prosthetic conduits inserted in the right ventricular outflow tract (RVOT). There has been little evaluation of the use of the Melody(®) valve for patched non-circular pulmonary pathways. To evaluate the outcomes of Melody valve insertion in patients with a patched non-circular RVOT. We analysed procedural and outcomes data from 34 patients who underwent Melody valve implantation for a non-circular RVOT. RVOT preparation was done in all patients, using different techniques (conventional, Russian doll and/or PA jailing). Melody valve insertion was performed concomitantly in most patients. All procedures were successful. Sixteen patients had complex additional procedures, including the jailing technique (n=5), the Russian doll technique (n=6) and multiple stent implantations (Russian jailing; n=5). The remaining patients were treated using the conventional technique with systematic prestenting. Three early complications occurred: one haemoptysis; one residual RVOT obstruction needing recatheterization 48 hours after percutaneous pulmonary valve implantation; and one stent embolization during advancement of the Ensemble(®) delivery system. The mean follow-up period was 2.6 years postprocedure. There was no stent fracture, migration or embolization. Two patients developed a significant paraprosthetic leak and one received a second Melody valve. Careful patient selection, balloon sizing and RVOT preparation with prestenting are required to create a safe landing zone for the Melody valve. Short-term follow-up shows excellent results with no stent fracture or migration and appears promising. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Quasi-Optical Techniques for Millimeter and Submillimeter-Wave Circuits.

DTIC Science & Technology

1981-03-25

permits non-destructive measurement. The cross section of the IS guide is shown in Fig. 4. We create a notch -type grating in the dielectric strip (rl). Then...the e-igenvalue equation is solved. 1he method was modified to minAlyze .a circular patch radiatlng st ructulre. l’ht, prote dtlrc i s essentIalIv...34Hankel transform domain analysis of open circular microstrip radiating structures," IEEE Trans. Antennas and Propagation, Vol. AP-29, Jan. 1981. 19. T

Coupling single giant nanocrystal quantum dots to the fundamental mode of patch nanoantennas through fringe field

DOE PAGES

Wang, Feng; Karan, Niladri S.; Minh Nguyen, Hue; ...

2015-09-23

Through single dot spectroscopy and numerical simulation studies, we demonstrate that the fundamental mode of gold patch nanoantennas have fringe-field resonance capable of enhancing the nano-emitters coupled around the edge of the patch antenna. This fringe-field coupling is used to enhance the radiative rates of core/thick-shell nanocrystal quantum dots (g-NQDs) that cannot be embedded into the ultra-thin dielectric gap of patch nanoantennas due to their large sizes. We attain 14 and 3 times enhancements in single exciton radiative decay rate and bi-exciton emission efficiencies of g-NQDs respectively, with no detectable metal quenching. Our numerical studies confirmed our experimental results andmore » further reveal that patch nanoantennas can provide strong emission enhancement for dipoles lying not only in radial direction of the circular patches but also in the direction normal to the antennas surface. Finally, this provides a distinct advantage over the parallel gap-bar antennas that can provide enhancement only for the dipoles oriented across the gap.« less

Rounding corners of nano-square patches for multispectral plasmonic metamaterial absorbers.

PubMed

Ayas, Sencer; Bakan, Gokhan; Dana, Aykutlu

2015-05-04

Multispectral metamaterial absorbers based on metal-insulator-metal nano-square patch resonators are studied here. For a geometry consisting of perfectly nano-square patches and vertical sidewalls, double resonances in the visible regime are observed due to simultaneous excitation of electric and magnetic plasmon modes. Although slightly modifying the sizes of the square patches makes the resonance wavelengths simply shift, rounding corners of the square patches results in emergence of a third resonance due to excitation of the circular cavity modes. Sidewall angle of the patches are also observed to affect the absorption spectra significantly. Peak absorption values for the triple resonance structures are strongly affected as the sidewall angle varies from 90 to 50 degrees. Rounded corners and slanted sidewalls are typical imperfections for lithographically fabricated metamaterial structures. The presented results suggest that imperfections caused during fabrication of the top nano-structures must be taken into account when designing metamaterial absorbers. Furthermore, it is shown that these fabrication imperfections can be exploited for improving resonance properties and bandwidths of metamaterials for various potential applications such as solar energy harvesting, thermal emitters, surface enhanced spectroscopies and photodetection.

DISTINCTIVE FINE-SCALE MORPHOLOGY OF HYDRATE RIDGE

NASA Astrophysics Data System (ADS)

Conlin, D.; Paull, C. K.; Caress, D. W.; Thomas, H.; Ussler, W.; Lundsten, E.; Thompson, D.

2009-12-01

High-resolution multibeam bathymetry (vertical precision of 0.15 m and horizontal resolution of 1.0 m) collected using an autonomous underwater vehicle (AUV) reveals in unprecedented detail the fine-scale morphology of the ridge crests on Hydrate Ridge, offshore Oregon. An inertial navigation system combined with a doppler velocity sonar allowed the AUV to fly pre-programmed grids with 150 m line spacing at 3 knots while maintaining an altitude of 50 m above the bottom. The data were collected on two 17.5-hour-long dives, one covering a 4.3 x 1.9 km area on the southern crest of Hydrate Ridge (769 to 930 m water depths) and the other covering a 5.2 x 2 km area on the northern crest of Hydrate Ridge (584 to 985 m water depths). These surveys cover the seafloor associated with gas hydrate research boreholes at ODP Sites 891 and 1245 to 1250). The southern crest of Hydrate Ridge is an area being considered for a cable-connected seafloor observatory. The surface of southern Hydrate Ridge is generally smooth except for two approximately circular patches with maximum diameters of 350 m and 500 m associated with a distinctive hummocky topography. The geometric relationships indicate that the edges of these patches are surrounded with small apparently erosional scarps and thus the strata exposed within the patches are stratigraphically lower than the surrounding smooth seafloor. The fine scale-topography within these patches is characterized by a highly irregular surface formed by small, sometimes circular ~0.5 m deep pits, local highs and lows separated by ~0.5 high ledges that could be formed by irregularly eroded bedding surfaces. Similar shapes also occur at larger scales. For example, a previously described feature called the “pinnacle” is a ~15 m topographic high in the center of one of these hummocky patches. The surface of northern Hydrate Ridge has similar patches of hummocky topography. However, the patches are more numerous, associated with greater relief, elongated in a NE-SW direction, and up to 1400 m long. Again, these patches appear to consist of more resistant strata that have been exposed by erosion. One crater-like feature is roughly circular with a raised rim surrounding a 40 m deep depression that is 300 m in diameter. A ridge extends over 600 m to the SW from the SW flank of this depression. This ridge has a trough near its crest that suggests it is an open crack associated with seafloor expansion formed when seafloor was up-lifted to form the ridge. Previous ROV and manned submersible dives indicate that methane-derived carbonates, chemosynthetic biological communities and near seafloor gas hydrate occurrences are associated with the patches of seafloor we now know are characterized by the distinctive hummocky topography. Apparently, these distinctive textures and seafloor features are produced by processes which are focused at methane-rich seafloor sites; however, previously available survey tools have not had the resolution to adequately image these features.

A hybrid finite element-boundary integral for the analysis of cavity-backed antennas of arbitrary shape

NASA Technical Reports Server (NTRS)

Gong, Jian; Volakis, John L.; Woo, A. C.; Wang, H. T. G.

1993-01-01

This is the final report on this project which was concerned with the analysis of cavity-backed antennas and more specifically spiral antennas. The project was a continuation of a previous analysis, which employed rectangular brick elements, and was, thus, restricted to planar rectangular patch antennas. A total of five reports were submitted under this project and we expect that at least four journal papers will result from the research described in these reports. The abstracts of the four previous reports are included. The first of the reports (028918-1-T) is over 75 pages and describes the general formulation using tetrahedral elements and the computer program. Report 028918-2-T was written after the completion of the computer program and reviews the capability of the analysis and associated software for planar circular rectangular patches and for a rectangular planar spiral. Measurements were also done at the University of Michigan and at Mission Research Corp. for the purpose of validating the software. We are pleased to acknowledge a partial support from Mission Research Corp. in carrying out the work described in this report. The third report (028918-3-T) describes the formulation and partial validation (using 2D data) for patch antennas on a circular platform. The 3D validation and development of the formulation for patch antennas on circular platforms is still in progress. The fourth report (028918-4-T) is basically an invited journal paper which will appear in the 'J. Electromagnetic Waves and Applications' in early 1994. It describes the application of the finite element method in electromagnetics and is primarily based on our work here at U-M. This final report describes the culmination of our efforts in characterizing complex cavity-backed antennas on planar platforms. The report describes for the first time the analysis of non-planar spirals and non-rectangular slot antennas as well as traditional planar patch antennas. The comparisons between measurements and calculations are truly impressive. Another unique aspect of this work is the incorporation of the FFT as part of the BiCG solver by overlaying a structured triangular mesh over the unstructured mesh. The implementation of this BiCG-FFT solution algorithm is important in minimizing the CPU and storage requirements. This final report will be submitted for publication in a refereed journal.

Dewetting-mediated pattern formation inside the coffee ring

NASA Astrophysics Data System (ADS)

Li, Weibin; Lan, Ding; Wang, Yuren

2017-04-01

The rearrangement of particles in the final stage of droplet evaporation has been investigated by utilizing differential interference contrast microscopy and the formation mechanism of a network pattern inside a coffee ring has been revealed. A tailored substrate with a circular hydrophilic domain is prepared to obtain thin liquid film containing monolayer particles. Real-time bottom-view images show that the evolution of a dry patch could be divided into three stages: rupture initiation, dry patch expansion, and drying of the residual liquid. A growing number of dry patches will repeat these stages to form the network patterns inside the ringlike stain. It can be shown that the suction effect promotes the rupture of the liquid film and the formation of the dry patch. The particle-assembling process is totally controlled by the liquid film dewetting and dominated by the surface tension of the liquid film, which eventually determine the ultimate deposition patterns.

Novel On-wafer Radiation Pattern Measurement Technique for MEMS Actuator Based Reconfigurable Patch Antennas

NASA Technical Reports Server (NTRS)

Simons, Rainee N.

2002-01-01

The paper presents a novel on-wafer, antenna far field pattern measurement technique for microelectromechanical systems (MEMS) based reconfigurable patch antennas. The measurement technique significantly reduces the time and the cost associated with the characterization of printed antennas, fabricated on a semiconductor wafer or dielectric substrate. To measure the radiation patterns, the RF probe station is modified to accommodate an open-ended rectangular waveguide as the rotating linearly polarized sampling antenna. The open-ended waveguide is attached through a coaxial rotary joint to a Plexiglas(Trademark) arm and is driven along an arc by a stepper motor. Thus, the spinning open-ended waveguide can sample the relative field intensity of the patch as a function of the angle from bore sight. The experimental results include the measured linearly polarized and circularly polarized radiation patterns for MEMS-based frequency reconfigurable rectangular and polarization reconfigurable nearly square patch antennas, respectively.

Quality Factor Effect on the Wireless Range of Microstrip Patch Antenna Strain Sensors

PubMed Central

Daliri, Ali; Galehdar, Amir; Rowe, Wayne S. T.; John, Sabu; Wang, Chun H.; Ghorbani, Kamran

2014-01-01

Recently introduced passive wireless strain sensors based on microstrip patch antennas have shown great potential for reliable health and usage monitoring in aerospace and civil industries. However, the wireless interrogation range of these sensors is limited to few centimeters, which restricts their practical application. This paper presents an investigation on the effect of circular microstrip patch antenna (CMPA) design on the quality factor and the maximum practical wireless reading range of the sensor. The results reveal that by using appropriate substrate materials the interrogation distance of the CMPA sensor can be increased four-fold, from the previously reported 5 to 20 cm, thus improving considerably the viability of this type of wireless sensors for strain measurement and damage detection. PMID:24451457

Quality factor effect on the wireless range of microstrip patch antenna strain sensors.

PubMed

Daliri, Ali; Galehdar, Amir; Rowe, Wayne S T; John, Sabu; Wang, Chun H; Ghorbani, Kamran

2014-01-02

Recently introduced passive wireless strain sensors based on microstrip patch antennas have shown great potential for reliable health and usage monitoring in aerospace and civil industries. However, the wireless interrogation range of these sensors is limited to few centimeters, which restricts their practical application. This paper presents an investigation on the effect of circular microstrip patch antenna (CMPA) design on the quality factor and the maximum practical wireless reading range of the sensor. The results reveal that by using appropriate substrate materials the interrogation distance of the CMPA sensor can be increased four-fold, from the previously reported 5 to 20 cm, thus improving considerably the viability of this type of wireless sensors for strain measurement and damage detection.

A Ka-Band (26 GHz) Circularly Polarized 2x2 Microstrip Patch Sub-Array with Compact Feed

NASA Technical Reports Server (NTRS)

Chrysler, Andrew; Furse, Cynthia; Simons, Rainee N.; Miranda, Felix A.

2017-01-01

A Ka-Band (26 gigahertz) 2 by 2 sub-array with square-shaped microstrip patch antenna elements having two truncated corners for circular polarization (CP) is presented. In addition, the layout for a new compact microstrip feed network for the sub-array is also presented. The compact feed network offers a footprint size reduction of near 60 percent over traditional sub-array at 26 gigahertz. Experimental data indicates that a truncation amount a equals 0.741 millimeters for an isolated patch element results in a return loss (S (sub II)) of minus 35 decibels at 26.3 gigahertz. Furthermore, the measured S (sub II) for the proof-of-concept sub-array with the above elements is better than minus 10.0 decibels at 27.7 gigahertz. However, the impedance match and the operating frequency can be fine-tuned to 26 gigahertz by adjusting the feed network dimensions. Lastly, good agreement is observed between the measured and simulated S (sub II) for the subarray for both right hand and left hand CP. The goal of this effort is utilize the above sub-array as a building block for a larger N by N element array, which would serve as a feed for a reflector antenna for satellite communications.

A Microstrip Patch-Fed Short Backfire Antenna for the Tracking and Data Relay Satellite System-Continuation (TDRSS-C) Multiple Access (MA) Array

NASA Technical Reports Server (NTRS)

Nessel, James A.; Kory, Carol L.; Lambert, Kevin M.; Acosta, Roberto J.

2006-01-01

Short Backfire Antennas (SBAs) are widely utilized for mobile satellite communications, tracking, telemetry, and wireless local area network (WLAN) applications due to their compact structure and excellent radiation characteristics [1-3]. Typically, these SBA s consist of an excitation element (i.e., a half-wavelength dipole), a reflective bottom plane, a planar sub-reflector located above the "exciter", and an outer circular rim. This configuration is capable of achieving gains on the order of 13-15 dBi, but with relatively narrow bandwidths (approx.3%-5%), making it incompatible with the requirements of the next generation enhanced Tracking and Data Relay Satellite System-Continuation (TDRSS-C) Multiple Access (MA) array [1]. Several attempts have been made to enhance the bandwidth performance of the common dipole-fed SBA by employing various other feeding mechanisms (e.g., waveguide, slot) with moderate success [4-5]. In this paper, a novel method of using a microstrip patch is employed for the first time to excite an SBA. The patch element is fed via two H-shaped slots electromagnetically coupled to a broadband hybrid coupler to maintain a wide bandwidth, as well as provide for dual circular polarization capabilities.

Block-induced Complex Structures Building the Flare-productive Solar Active Region 12673

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

Yang, Shuhong; Zhang, Jun; Zhu, Xiaoshuai

Solar active region (AR) 12673 produced 4 X-class, 27 M-class, and numerous lower-class flares during its passage across the visible solar disk in 2017 September. Our study is to answer the questions why this AR was so flare-productive and how the X9.3 flare, the largest one of the past decade, took place. We find that there was a sunspot in the initial several days, and then two bipolar regions emerged nearby it successively. Due to the standing of the pre-existing sunspot, the movement of the bipoles was blocked, while the pre-existing sunspot maintained its quasi-circular shaped umbra only with themore » disappearance of a part of penumbra. Thus, the bipolar patches were significantly distorted, and the opposite polarities formed two semi-circular shaped structures. After that, two sequences of new bipolar regions emerged within the narrow semi-circular zone, and the bipolar patches separated along the curved channel. The new bipoles sheared and interacted with the previous ones, forming a complex topological system, during which numerous flares occurred. At the highly sheared region, a great deal of free energy was accumulated. On September 6, one negative patch near the polarity inversion line began to rapidly rotate and shear with the surrounding positive fields, and consequently the X9.3 flare erupted. Our results reveal that the block-induced complex structures built the flare-productive AR and the X9.3 flare was triggered by an erupting filament due to the kink instability. To better illustrate this process, a block-induced eruption model is proposed for the first time.« less

Comparison of actual and seismologically inferred stress drops in dynamic models of microseismicity

NASA Astrophysics Data System (ADS)

Lin, Y. Y.; Lapusta, N.

2017-12-01

Estimating source parameters for small earthquakes is commonly based on either Brune or Madariaga source models. These models assume circular rupture that starts from the center of a fault and spreads axisymmetrically with a constant rupture speed. The resulting stress drops are moment-independent, with large scatter. However, more complex source behaviors are commonly discovered by finite-fault inversions for both large and small earthquakes, including directivity, heterogeneous slip, and non-circular shapes. Recent studies (Noda, Lapusta, and Kanamori, GJI, 2013; Kaneko and Shearer, GJI, 2014; JGR, 2015) have shown that slip heterogeneity and directivity can result in large discrepancies between the actual and estimated stress drops. We explore the relation between the actual and seismologically estimated stress drops for several types of numerically produced microearthquakes. For example, an asperity-type circular fault patch with increasing normal stress towards the middle of the patch, surrounded by a creeping region, is a potentially common microseismicity source. In such models, a number of events rupture the portion of the patch near its circumference, producing ring-like ruptures, before a patch-spanning event occurs. We calculate the far-field synthetic waveforms for our simulated sources and estimate their spectral properties. The distribution of corner frequencies over the focal sphere is markedly different for the ring-like sources compared to the Madariaga model. Furthermore, most waveforms for the ring-like sources are better fitted by a high-frequency fall-off rate different from the commonly assumed value of 2 (from the so-called omega-squared model), with the average value over the focal sphere being 1.5. The application of Brune- or Madariaga-type analysis to these sources results in the stress drops estimates different from the actual stress drops by a factor of up to 125 in the models we considered. We will report on our current studies of other types of seismic sources, such as repeating earthquakes and foreshock-like events, and whether the potentially realistic and common sources different from the standard Brune and Madariaga models can be identified from their focal spectral signatures and studied using a more tailored seismological analysis.

Multi-Body Capture to Low-altitude Circular Orbits at Europa

NASA Technical Reports Server (NTRS)

Grebow, Daniel J.; Petropoulos, Anastassios E.; Finlayson, Paul A.

2011-01-01

For capture to a 200-km circular orbit around Europa, millions of different points along the orbit are simulated in the Jupiter-Europa Restricted 3-Body Problem. The transfers exist as members of families of trajectories, where certain families consistently outperform the others. The trajectories are not sensitive to changes in inclination for the final circular orbit. The top performing trajectories appear to follow the invariant manifolds of L2 Lyapunov orbits for capture into a retrograde orbit, and in some cases saving up to 40% of the from the patched 2-body problem. Transfers are attached to the current nominal mission for NASA's Jupiter-Europa Orbiter, where the total cost is roughly 100 m/s less than the baseline mission.

A multi-layer circularly polarized microstrip patch antenna with proximity coupling and increased gain

NASA Technical Reports Server (NTRS)

Zawadzki, M.

2001-01-01

Presented is a description of the single stacked element, and measured and calculated results at 2.56 GHz. Also included are measured results for the array, and calculated results of a stacked element for the required frequency-scaled version at 32 GHz.

Wideband Microstrip Antenna-Feeding Array

NASA Technical Reports Server (NTRS)

Huang, John

1990-01-01

Special impedance-matching probes help reduce feed complexity. Lightweight array of microstrip antenna elements designed to transmit and illuminate reflector antenna with circularly polarized radiation at 1,545 to 1,550 MHz and to receive circularly polarized radiation at 1,646 to 1,660 MHz. Microstrip array is cluster of 7 subarrays containing total of 28 microstrip patches. Produces cicularly polarized beam with suitable edge taper to illuminate reflector antenna. Teardrop-shaped feed probe provides gradual change of field from coaxial transmission line into microstrip substrate. Intended to be part of larger overlapping-cluster array generating multiple contiguous beams.

A linear-to-circular polarization converter based on a second-order band-pass frequency selective surface

NASA Astrophysics Data System (ADS)

Lin, Baoqin; Wu, Jia-liang; Da, Xin-yu; Li, Wei; Ma, Jia-jun

2017-01-01

In this work, we propose a linear-to-circular transmission polarization converter based on a second-order band-pass frequency selective surface (FSS). The FSS is composed of a three-layer aperture-coupled-patch structure, it can be interpreted as an array of antenna-filter-antenna modules, wherein the antenna is just a circularly polarized corner-truncated square microstrip antenna. A prototype of the proposed polarization converter is analyzed, fabricated and tested. Both simulation and experimental results show that the 3-dB axial ratio relative bandwidth of the polarization converter is over 30%, and the maximum insertion loss is only 1.87 dB; in addition, it can maintain good performance over a wide angular bandwidth at TE incidence.

How stellar feedback simultaneously regulates star formation and drives outflows

NASA Astrophysics Data System (ADS)

Hayward, Christopher C.; Hopkins, Philip F.

2017-02-01

We present an analytic model for how momentum deposition from stellar feedback simultaneously regulates star formation and drives outflows in a turbulent interstellar medium (ISM). Because the ISM is turbulent, a given patch of ISM exhibits sub-patches with a range of surface densities. The high-density patches are 'pushed' by feedback, thereby driving turbulence and self-regulating local star formation. Sufficiently low-density patches, however, are accelerated to above the escape velocity before the region can self-adjust and are thus vented as outflows. When the gas fraction is ≳ 0.3, the ratio of the turbulent velocity dispersion to the circular velocity is sufficiently high that at any given time, of the order of half of the ISM has surface density less than the critical value and thus can be blown out on a dynamical time. The resulting outflows have a mass-loading factor (η ≡ dot{M}_{out}/M_{star }) that is inversely proportional to the gas fraction times the circular velocity. At low gas fractions, the star formation rate needed for local self-regulation, and corresponding turbulent Mach number, declines rapidly; the ISM is 'smoother', and it is actually more difficult to drive winds with large mass-loading factors. Crucially, our model predicts that stellar-feedback-driven outflows should be suppressed at z ≲ 1 in M⋆ ≳ 1010 M⊙ galaxies. This mechanism allows massive galaxies to exhibit violent outflows at high redshifts and then 'shut down' those outflows at late times, thereby enabling the formation of a smooth, extended thin stellar disc. We provide simple fitting functions for η that should be useful for sub-resolution and semi-analytic models.

Microstrip Yagi Antenna with Dual Aperture-Coupled Feed

NASA Technical Reports Server (NTRS)

Pogorzelski, Ronald; Venkatesan, Jaikrishna

2008-01-01

A proposed microstrip Yagi antenna would operate at a frequency of 8.4 GHz (which is in the X band) and would feature a mechanically simpler, more elegant design, relative to a prior L-band microstrip Yagi antenna. In general, the purpose of designing a microstrip Yagi antenna is to combine features of a Yagi antenna with those of a microstrip patch to obtain an antenna that can be manufactured at low cost, has a low profile, and radiates a directive beam that, as plotted on an elevation plane perpendicular to the antenna plane, appears tilted away from the broadside. Such antennas are suitable for flush mounting on surfaces of diverse objects, including spacecraft, aircraft, land vehicles, and computers. Stated somewhat more precisely, what has been proposed is a microstrip antenna comprising an array of three Yagi elements. Each element would include four microstrip-patch Yagi subelements: one reflector patch, one driven patch, and two director patches. To obtain circular polarization, each driven patch would be fed by use of a dual offset aperture-coupled feed featuring bow-tie-shaped apertures. The selection of the dual offset bow-tie aperture geometry is supported by results found in published literature that show that this geometry would enable matching of the impedances of the driven patches to the 50-Omega impedance of the microstrip feedline while maintaining a desirably large front-to-back lobe ratio.

Disentangling the role of seed bank and dispersal in plant metapopulation dynamics using patch occupancy surveys.

PubMed

Manna, F; Pradel, R; Choquet, R; Fréville, H; Cheptou, P-O

2017-10-01

In plants, the presence of a seed bank challenges the application of classical metapopulation models to aboveground presence surveys; ignoring seed bank leads to overestimated extinction and colonization rates. In this article, we explore the possibility to detect seed bank using hidden Markov models in the analysis of aboveground patch occupancy surveys of an annual plant with limited dispersal. Patch occupancy data were generated by simulation under two metapopulation sizes (N = 200 and N = 1,000 patches) and different metapopulation scenarios, each scenario being a combination of the presence/absence of a 1-yr seed bank and the presence/absence of limited dispersal in a circular 1-dimension configuration of patches. In addition, because local conditions often vary among patches in natural metapopulations, we simulated patch occupancy data with heterogeneous germination rate and patch disturbance. Seed bank is not observable from aboveground patch occupancy surveys, hence hidden Markov models were designed to account for uncertainty in patch occupancy. We explored their ability to retrieve the correct scenario. For 10 yr surveys and metapopulation sizes of N = 200 or 1,000 patches, the correct metapopulation scenario was detected at a rate close to 100%, whatever the underlying scenario considered. For smaller, more realistic, survey duration, the length for a reliable detection of the correct scenario depends on the metapopulation size: 3 yr for N = 1,000 and 6 yr for N = 200 are enough. Our method remained powerful to disentangle seed bank from dispersal in the presence of patch heterogeneity affecting either seed germination or patch extinction. Our work shows that seed bank and limited dispersal generate different signatures on aboveground patch occupancy surveys. Therefore, our method provides a powerful tool to infer metapopulation dynamics in a wide range of species with an undetectable life form. © 2017 by the Ecological Society of America.

The C-patch - A small microstrip element

NASA Astrophysics Data System (ADS)

Kossiavas, G.; Papiernik, A.; Boisset, J. P.; Sauvan, M.

1989-02-01

A radiating element operating in the UHF and L-bands is presented. The element has dimensions smaller than those of conventional square or circular elements. For this type of antenna, good matching is obtained with a coaxial feed, and the omnidirectional radiation pattern is achieved using linear polarization. The bandwidth, however, remains somewhat narrow.

Properties of Silica-Based Aerogel Substrates and Application to C-Band Circular Patch Antenna

NASA Astrophysics Data System (ADS)

Abdel-Rahman, Mohamed; Haraz, Osama M.; Ashraf, Nadeem; Zia, Muhammad Fakhar; Khaled, Usama; Elsahfiey, Ibrahim; Alshebeili, Saleh; Sebak, Abdel Razik

2018-03-01

Silica aerogel is a lightweight and low-permittivity dielectric material that possesses attractive features for use as an antenna substrate. In this paper, we characterize the radio frequency and microwave dielectric permittivity properties of substrates composed of silica aerogel encapsulated in polymer aerogel in the frequency range from 10 MHz to 8.5 GHz. Characterized silica-based aerogel substrates show relative permittivity values varying between 1.055 and 1.25 and loss tangent values ranging from 5.08 × 10-4 to 0.0206. Silica-based aerogel substrates thus have the potential of use in designing antennas with high gain and large bandwidth. Validation is presented by characterizing the performance of a manufactured C-band circular patch antenna on silica-based aerogel substrate. The performance is also compared to a design that uses Rogers Duroid RT5880 substrate. The results reveal that the silica aerogel substrate antenna at 7.2 GHz provides 1.5 dB increase in gain, 88% enhancement in bandwidth and 68.5% reduction in mass, in comparison with the antenna on RT5880 substrate.

Characteristics of aperiodic sequence of slip events caused by interaction between seismic patches and that caused be self-organized stress heterogeneity

NASA Astrophysics Data System (ADS)

Kato, N.

2017-12-01

Numerical simulations of earthquake cycles are conducted to investigate the origin of complexity of earthquake recurrence. There are two main causes of the complexity. One is self-organized stress heterogeneity due to dynamical effect. The other is the effect of interaction between some fault patches. In the model, friction on the fault is assumed to obey a rate- and state-dependent friction law. Circular patches of velocity-weakening frictional property are assumed on the fault. On the remaining areas of the fault, velocity-strengthening friction is assumed. We consider three models: Single patch model, two-patch model, and three-patch model. In the first model, the dynamical effect is mainly examined. The latter two models take into consideration the effect of interaction as well as the dynamical effect. Complex multiperiodic or aperiodic sequences of slip events occur when slip behavior changes from the seismic to aseismic, and when the degree of interaction between seismic patches is intermediate. The former is observed in all the models, and the latter is observed in the two-patch model and the three-patch model. Evolution of spatial distribution of shear stress on the fault suggests that aperiodicity at the transition from seismic to aseismic slip is caused by self-organized stress heterogeneity. The iteration maps of recurrence intervals of slip events in aperiodic sequences are examined, and they are approximately expressed by simple curves for aperiodicity at the transition from seismic to aseismic slip. In contrast, the iteration maps for aperiodic sequences caused by interaction between seismic patches are scattered and they are not expressed by simple curves. This result suggests that complex sequences caused by different mechanisms may be distinguished.

Superficial heat reduction technique for a hybrid microwave-optical device.

PubMed

Al-Armaghany, A; Tong, K; Leung, T S

2013-01-01

Microwave applicator in the form of a circularly polarized microstrip patch antenna is proposed to provide localized deep heating in biological tissue, which causes blood vessels to dilate leading to changes in tissue oxygenation. These changes are monitored by an integrated optical system for studying thermoregulation in different parts of the human body. Using computer simulations, this paper compares circularly and linearly polarized antennas in terms of the efficiency of depositing electromagnetic (EM) energy and the heating patterns. The biological model composes of the skin, fat and muscle layers with appropriate dielectric and thermal properties. The results show that for the same specific absorption rate (SAR) in the muscle, the circularly polarized antenna results in a lower SAR in the skin-fat interface than the linearly polarized antenna. The thermal distribution is also presented based on the biological heat equation. The proposed circularly polarized antenna shows heat reduction in the superficial layers in comparison to the linearly polarized antenna.

Input impedance of a probe-fed circular microstrip antenna with thick substrate

NASA Technical Reports Server (NTRS)

Davidovitz, M.; Lo, Y. T.

1986-01-01

A method of computing the input impedance for the probe fed circular microstrip antenna with thick dielectric substrate is presented. Utilizing the framework of the cavity model, the fields under the microstrip patch are expanded in a set of modes satisfying the boundary conditions on the eccentrically located probe, as well as on the cavity magnetic wall. A mode-matching technique is used to solve for the electric field at the junction between the cavity and the coaxial feed cable. The reflection coefficient of the transverse electromagnetic (TEM) mode incident in the coaxial cable is determined, from which the input impedance of the antenna is computed. Measured data are presented to verify the theoretical calculations. Results of the computation of various losses for the circular printed antenna as a function of substrate thickness are also included.

Superconducting antennas for telecommunication applications based on dual mode cross slotted patches

NASA Astrophysics Data System (ADS)

Cassinese, A.; Barra, M.; Fragalà, I.; Kusunoki, M.; Malandrino, G.; Nakagawa, T.; Perdicaro, L. M. S.; Sato, K.; Ohshima, S.; Vaglio, R.

2002-08-01

Dual mode devices based on high temperature superconducting films represent an interesting class for telecommunication applications since they combine a miniaturized size with a good power handling. Here we report on a novel compact antenna obtained by crossing a square patch with two or more slots. The proposed design has an antenna size reduction of about 40% as compared to the conventional square patch microstrip antennas. Single patch antenna both with linear (LP) and circular (CP) polarization operating in the X-band have been designed and tested at prototype level. They are realized by using double sided (YBa 2Cu 3O 7- x) YBCO and Tl 2Ba 2Ca 1Cu 2O 8 (Tl-2212) superconducting films grown on MgO substrates and tested with a portable cryocooler. They showed at T=77 K a return loss <25 dB and a power handling of 23 dBm. Exemplary 16 elements arrays LP antennas operating in the X band have been also realized by using YBCO film grown on 2 ″ diameter MgO substrate.

Multi-Patches IRIS Based Person Authentication System Using Particle Swarm Optimization and Fuzzy C-Means Clustering

NASA Astrophysics Data System (ADS)

Shekar, B. H.; Bhat, S. S.

2017-05-01

Locating the boundary parameters of pupil and iris and segmenting the noise free iris portion are the most challenging phases of an automated iris recognition system. In this paper, we have presented person authentication frame work which uses particle swarm optimization (PSO) to locate iris region and circular hough transform (CHT) to device the boundary parameters. To undermine the effect of the noise presented in the segmented iris region we have divided the candidate region into N patches and used Fuzzy c-means clustering (FCM) to classify the patches into best iris region and not so best iris region (noisy region) based on the probability density function of each patch. Weighted mean Hammimng distance is adopted to find the dissimilarity score between the two candidate irises. We have used Log-Gabor, Riesz and Taylor's series expansion (TSE) filters and combinations of these three for iris feature extraction. To justify the feasibility of the proposed method, we experimented on the three publicly available data sets IITD, MMU v-2 and CASIA v-4 distance.

Moment Method Solutions for Radiation and Scattering from Arbitrarily Shaped Surfaces.

DTIC Science & Technology

1981-02-01

IBM -370/168. A. Monopole Antenna on a Disk The study of the monopole antenna on a circular disk is of inter- est since it leads to the understanding...34 . . ._"-", - CHAPTER V ANALYSIS OF MICRUSI- itP ANTL-NNAS This chapter will present an analysis of the microstrip antenna. Surface-patch dipole modes are used to

Photographer : JPL Range : 862,200 km. ( 500,000 miles ) This photograph shows subspacecraft

NASA Technical Reports Server (NTRS)

1979-01-01

Photographer : JPL Range : 862,200 km. ( 500,000 miles ) This photograph shows subspacecraft longitude of approximately 146 degrees of Jupiter's moon Io. Circular features are seen that may be meteorite impact craters or features of internal origins. Irregular depressions are seen that indicate surface modifications. The bright irregular patches appear to be younger deposits masking the surface detail.

Advanced electromagnetic methods for aerospace vehicles

NASA Technical Reports Server (NTRS)

Balanis, Constantine A.; El-Sharawy, El-Budawy; Hashemi-Yeganeh, Shahrokh; Aberle, James T.; Birtcher, Craig R.

1991-01-01

The Advanced Helicopter Electromagnetics is centered on issues that advance technology related to helicopter electromagnetics. Progress was made on three major topics: composite materials; precipitation static corona discharge; and antenna technology. In composite materials, the research has focused on the measurements of their electrical properties, and the modeling of material discontinuities and their effect on the radiation pattern of antennas mounted on or near material surfaces. The electrical properties were used to model antenna performance when mounted on composite materials. Since helicopter platforms include several antenna systems at VHF and UHF bands, measuring techniques are being explored that can be used to measure the properties at these bands. The effort on corona discharge and precipitation static was directed toward the development of a new two dimensional Voltage Finite Difference Time Domain computer program. Results indicate the feasibility of using potentials for simulating electromagnetic problems in the cases where potentials become primary sources. In antenna technology the focus was on Polarization Diverse Conformal Microstrip Antennas, Cavity Backed Slot Antennas, and Varactor Tuned Circular Patch Antennas. Numerical codes were developed for the analysis of two probe fed rectangular and circular microstrip patch antennas fed by resistive and reactive power divider networks.

Optimization of Planar Monopole Wideband Antenna for Wireless Communication System

PubMed Central

Moghavvemi, Mahmoud; Mahadi, Wan Nor Liza

2016-01-01

In this paper, a new compact wideband monopole antenna is presented for wireless communication applications. This antenna comprises of a new radiating patch, a new arc-shaped strip, microstrip feed line, and a notched ground plane. The proposed radiating patch is combined with a rectangular and semi-circular patch and is integrated with a partial ground plane to provide a wide impedance bandwidth. The new arc-shaped strip between the radiating patch and microstrip feed line creates an extra surface on the patch, which helps further widen the bandwidth. Inserting one step notch on the ground plane further enhances the bandwidth. The antenna has a compact size of 16×20×1.6mm3. The measured result indicated that the antenna achieves a 127% bandwidth at VSWR≤2, ranging from 4.9GHz to 22.1GHz. Stable radiation patterns with acceptable gain are achieved. Also, a measured bandwidth of 107.7% at VSWR≤1.5 (5.1-17GHz) is obtained, which is suitable for UWB outdoor propagation. This antenna is compatible with a good number of wireless standards, including UWB band, Wimax 5.4 GHz band, MVDDS (12.2–12.7GHz), and close range radar and satellite communication in the X-band (8-12GHz), and Ku band (12-18GHz). PMID:27992466

Optimization of Planar Monopole Wideband Antenna for Wireless Communication System.

PubMed

Shakib, Mohammed Nazmus; Moghavvemi, Mahmoud; Mahadi, Wan Nor Liza

2016-01-01

In this paper, a new compact wideband monopole antenna is presented for wireless communication applications. This antenna comprises of a new radiating patch, a new arc-shaped strip, microstrip feed line, and a notched ground plane. The proposed radiating patch is combined with a rectangular and semi-circular patch and is integrated with a partial ground plane to provide a wide impedance bandwidth. The new arc-shaped strip between the radiating patch and microstrip feed line creates an extra surface on the patch, which helps further widen the bandwidth. Inserting one step notch on the ground plane further enhances the bandwidth. The antenna has a compact size of 16×20×1.6mm3. The measured result indicated that the antenna achieves a 127% bandwidth at VSWR≤2, ranging from 4.9GHz to 22.1GHz. Stable radiation patterns with acceptable gain are achieved. Also, a measured bandwidth of 107.7% at VSWR≤1.5 (5.1-17GHz) is obtained, which is suitable for UWB outdoor propagation. This antenna is compatible with a good number of wireless standards, including UWB band, Wimax 5.4 GHz band, MVDDS (12.2-12.7GHz), and close range radar and satellite communication in the X-band (8-12GHz), and Ku band (12-18GHz).

Novel Microstrip Patch Antennas with Frequency Agility, Polarization Reconfigurability, Dual Null Steering Capability and Phased Array Antenna with Beam Steering Performance

NASA Astrophysics Data System (ADS)

Babakhani, Behrouz

Nowadays the wireless communication technology is playing an important role in our daily life. People use wireless devices not only as a conventional communication device but also as tracking and navigation tool, web browsing tool, data storage and transfer tool and so for many other reasons. Based on the user demand, wireless communication engineers try to accommodate as many as possible wireless systems and applications in a single device and therefore, creates a multifunctional device. Antenna, as an integral part of any wireless communication systems, should also be evolved and adjusted with development of wireless transceiver systems. Therefore multifunctional antennas have been introduced to support and enhance the functionality on modern wireless systems. The main focus and contribution of this thesis is design of novel multifunctional microstrip antennas with frequency agility, polarization reconfigurablity, dual null steering capability and phased array antenna with beam steering performance. In this thesis, first, a wide bandwidth(1.10 GHz to 1.60 GHz) right-handed circularly polarized (RHCP) directional antenna for global positioning system (GPS) satellite receive application has been introduced which covers all the GPS bands starting from L1 to L5. This design consists of two crossed bow-tie dipole antennas fed with sequentially phase rotated feed network backed with an artificial high impedance surface (HIS) structure to generate high gain directional radiation patterns. This design shows good CP gain and axial ratio (AR) and wide beamwidth performance. Although this design has good radiation quality, the size and the weight can be reduced as future study. In the second design, a frequency agile antenna was developed which also covers the L-band (L1 to L5) satellite communication frequencies. This frequency agile antenna was designed and realized by new implementation of varactor diodes in the geometry of a circular patch antenna. Beside wide frequency agility (1.17 GHz to 1.58 GHz), full polarization reconfiguration was added to the design by controlling ports excitation of circular patch using RF switches (vertical linear, horizontal linear, right-handed circular polarization (RHCP) and left-handed circular polarization (LHCP)). This deign maintains good gain and radiation efficiency over the tunable range as well as acceptable co-polarization and cross-polarization separation for different polarizations. Since many communications applications require beam steering ability, in our third design, we designed and developed a linear phased array antenna using a modified version of our frequency agile polarization reconfigurable antenna for beam steering applications. This design offers wide frequency agility (1.50 GHz to 2.40 GHz), full polarization reconfiguration (vertical linear, horizontal linear, LHCP and RHCP) as well as beam steering of +/-52° and +/-28° at 1.5 GHz and 2.4 GHz, respectively. In this 1x4 array, the excitation magnitude and phase of each element was controlled by an analog beamforming feed network (BFN) for beam steering purposes. The required excitation for each element to steer the beam toward a desired location was calculated using projection matrix method (PMM) which uses measured active element pattern (AEP) as its input. This array antenna performance for frequency agility, radiation quality for each polarization and beam steering capability was obtained in the acceptable range. In the last design, the full spherical dual null steering capability of a triple mode circular microstrip patch antenna was investigated. By combining the radiation patterns of three individual modes of microstrip circular patch antenna, two nulls have been generated. These nulls can be repositioned in the upper hemisphere by controlling excitation ratio of each mode. The modes excitation ratio to steer the nulls toward the desired positions was calculated using a derivative free hybrid optimization method. This optimization method uses particle swarm optimization (PSO) combined with pattern search (PS) to find the optimum modes excitation ratio which minimizes the received power at the null positions. The calculated coefficients were applied to the multimode antenna using an analog BFN. This design shows an independent dual null steering with null depth of around 20 dB. Discussion about the proposed antennas included detailed theoretical analysis, numerical simulation and optimizations, beam forming and null steering algorithms, fabrication of the antennas and its control/beamforming feed networks along with the associated bias networks, microcontroller units, and finally its characterization (impedance matching, gain and 2D and 3D radiation patterns). The research work was performed at the Antenna and Microwave Lab (AML) which has the required resources including full wave analysis tools, PCB milling machine, surface mount component soldering station, vector network analyzers, and far-field/spherical near-field radiation pattern measurement system.

Experimental confirmation of a PDE-based approach to design of feedback controls

NASA Technical Reports Server (NTRS)

Banks, H. T.; Smith, Ralph C.; Brown, D. E.; Silcox, R. J.; Metcalf, Vern L.

1995-01-01

Issues regarding the experimental implementation of partial differential equation based controllers are discussed in this work. While the motivating application involves the reduction of vibration levels for a circular plate through excitation of surface-mounted piezoceramic patches, the general techniques described here will extend to a variety of applications. The initial step is the development of a PDE model which accurately captures the physics of the underlying process. This model is then discretized to yield a vector-valued initial value problem. Optimal control theory is used to determine continuous-time voltages to the patches, and the approximations needed to facilitate discrete time implementation are addressed. Finally, experimental results demonstrating the control of both transient and steady state vibrations through these techniques are presented.

Development of an omni-directional shear horizontal mode magnetostrictive patch transducer

NASA Astrophysics Data System (ADS)

Liu, Zenghua; Hu, Yanan; Xie, Muwen; Fan, Junwei; He, Cunfu; Wu, Bin

2018-04-01

The fundamental shear horizontal wave, SH0 mode, has great potential in defect detection and on-line monitoring with large scale and high efficiency in plate-like structures because of its non-dispersive characteristics. Aiming at consistently exciting single SH0 mode in plate-like structures, an omni-directional shear horizontal mode magnetostrictive patch transducer (OSHM-MPT) is developed on the basis of magnetostrictive effect. It consists of four fan-shaped array elements and corresponding plane solenoid array (PSA) coils, four fan-shaped permanent magnets and a circular nickel patch. The experimental results verify that the developed transducer can effectively produce the single SH0 mode in an aluminum plate. The frequency response characteristics of this developed transducer are tested. The results demonstrate that the proposed OSHM-MPT has a center frequency of 300kHz related to the distance between adjacent arc-shaped steps of the PSA coils. Furthermore, omni-directivity of this developed transducer is tested. The results demonstrate that the developed transducer has a high omnidirectional consistency.

Nanoplasmonic lenses for bacteria sorting (Presentation Recording)

NASA Astrophysics Data System (ADS)

Zhu, Xiangchao; Yanik, Ahmet A.

2015-08-01

We demonstrate that patches of two dimensional arrays of circular plasmonic nanoholes patterned on gold-titanium thin film enables subwavelength focusing of visible light in far field region. Efficient coupling of the light with the excited surface plasmon at metal dielectric interface results in strong light transmission. As a result, surface plasmon plays an important role in the far field focusing behavior of the nanohole-aperture patches device. Furthermore, the focal length of the focused beam was found to be predominantly dependent on the overall size of the patch, which is in good agreement with that calculated by Rayleigh-Sommerfield integral formula. The focused light beam can be utilized to separate bio-particles in the dynamic range from 0.1 μm to 1 μm through mainly overcoming the drag force induced by fluid flow. In our proposed model, focused light generated by our plasmonic lenses will push the larger bio-particles in size back to the source of fluid flow and allow the smaller particles to move towards the central aperture of the patch. Such a new kind of plasmonic lenses open up possibility of sorting bacterium-like particles with plasmonic nanolenses, and also represent a promising tool in the field of virology.

Regions of mid-level human visual cortex sensitive to the global coherence of local image patches.

PubMed

Mannion, Damien J; Kersten, Daniel J; Olman, Cheryl A

2014-08-01

The global structural arrangement and spatial layout of the visual environment must be derived from the integration of local signals represented in the lower tiers of the visual system. This interaction between the spatially local and global properties of visual stimulation underlies many of our visual capacities, and how this is achieved in the brain is a central question for visual and cognitive neuroscience. Here, we examine the sensitivity of regions of the posterior human brain to the global coordination of spatially displaced naturalistic image patches. We presented observers with image patches in two circular apertures to the left and right of central fixation, with the patches drawn from either the same (coherent condition) or different (noncoherent condition) extended image. Using fMRI at 7T (n = 5), we find that global coherence affected signal amplitude in regions of dorsal mid-level cortex. Furthermore, we find that extensive regions of mid-level visual cortex contained information in their local activity pattern that could discriminate coherent and noncoherent stimuli. These findings indicate that the global coordination of local naturalistic image information has important consequences for the processing in human mid-level visual cortex.

Design of broadband single polarized antenna

NASA Astrophysics Data System (ADS)

Shin, Phoo Kho; Aziz, Mohamad Zoinol Abidin Abd.; Ahmad, Badrul Hisham; Ramli, Mohamad Hafize Bin; Fauzi, Noor Azamiah Md; Malek, Mohd Fareq Abd

2015-05-01

In practical wireless communication application, bandwidth enhancement becomes one of the major design considerations. At the same time, circular polarized (CP) antenna received much attention for the applications of modern wireless communication system when compared to linear polarized (LP) antenna. This is because CP antenna can reduce the multipath effect. Hence, broadband antenna with operating frequency at 2.4GHz for WLAN application is proposed. The proposed antenna is done by using L-probe amendment with rectangular patch. The rectangular patch and copper ground plane is separated with 10mm air gap. This approach is used to enhance the bandwidth and the gain of the proposed antenna. The bandwidth of the designed antenna is more than 200MHz which meet broadband application. The return loss for the antenna is below -10dB to achieved 90% matching efficiency. The position of L-probe feed is altered in order to obtained different polarizations. The broadband antenna had been designed and simulated by using Computer Simulation Technology (CST) software. In this paper, the comparison for single polarized antenna with the design of non-inverted patch and inverted patch is discussed. The characteristics of the S-parameter, axial ratio, gain, surface current for each designed antenna are analyzed.

Reef Development on Artificial Patch Reefs in Shallow Water of Panjang Island, Central Java

NASA Astrophysics Data System (ADS)

Munasik; Sugiyanto; Sugianto, Denny N.; Sabdono, Agus

2018-02-01

Reef restoration methods are generally developed by propagation of coral fragments, coral recruits and provide substrate for coral attachment using artificial reefs (ARs). ARs have been widely applied as a tool for reef restoration in degraded natural reefs. Successful of coral restoration is determined by reef development such as increasing coral biomass, natural of coral recruits and fauna associated. Artificial Patch Reefs (APRs) is designed by combined of artificial reefs and coral transplantation and constructed by modular circular structures in shape, were deployed from small boats by scuba divers, and are suitable near natural reefs for shallow water with low visibility of Panjang Island, Central Java. Branching corals of Acropora aspera, Montipora digitata and Porites cylindrica fragments were transplanted on to each module of two units of artificial patch reefs in different periods. Coral fragments of Acropora evolved high survival and high growth, Porites fragments have moderate survival and low growth, while fragment of Montipora show in low survival and moderate growth. Within 19 to 22 months of APRs deployment, scleractinian corals were recruited on the surface of artificial patch reef substrates. The most recruits abundant was Montastrea, followed by Poritids, Pocilloporids, and Acroporids. We conclude that artificial patch reefs with developed by coral fragments and natural coral recruitment is one of an alternative rehabilitation method in shallow reef with low visibility.

Advanced Antennas Enabled by Electromagnetic Metamaterials

DTIC Science & Technology

2014-12-01

radiation patterns of a conical horn antenna and three soft horns with various homogeneous metasurface liners. The maximum cross-polarization level was...inhomogencous metasurface liners covering both the flared horn section and the straight waveguide section. The mctahorn is fed by a circular waveguide...with a diameter of 20 mm. (b) The sizes of the metallic patches at each row of the metasurface in the flared horn section. Both the length and width

A PDE-based methodology for modeling, parameter estimation and feedback control in structural and structural acoustic systems

NASA Technical Reports Server (NTRS)

Banks, H. T.; Brown, D. E.; Metcalf, Vern L.; Silcox, R. J.; Smith, Ralph C.; Wang, Yun

1994-01-01

A problem of continued interest concerns the control of vibrations in a flexible structure and the related problem of reducing structure-borne noise in structural acoustic systems. In both cases, piezoceramic patches bonded to the structures have been successfully used as control actuators. Through the application of a controlling voltage, the patches can be used to reduce structural vibrations which in turn lead to methods for reducing structure-borne noise. A PDE-based methodology for modeling, estimating physical parameters, and implementing a feedback control scheme for problems of this type is discussed. While the illustrating example is a circular plate, the methodology is sufficiently general so as to be applicable in a variety of structural and structural acoustic systems.

Analysis of Petal Rotation Trajectory Characteristics

NASA Technical Reports Server (NTRS)

Anderson, Rodney L.; Campagnola, Stefano; Buffington, Brent B.

2014-01-01

In this study, the characteristics of petal rotation trajectories are explored in both the two-body and circular restricted three-body problem (CRTBP) models. Petal rotation trajectories alternate long and short resonances of different kinds to rotate the line of apsides. They are typically computed using the patched conic model, and they are used in a number of different missions and mission concepts including Cassini, JUICE, and Europa mission concepts. Petal rotation trajectories are first analyzed here using the patched conic model to quantify their characteristics and search for cases with fast rotation of the line of apsides. When they are computed in the CRTBP, they are unstable periodic orbits with corresponding stable and unstable manifolds. The characteristics of these orbits are explored from a dynamical systems perspective in the second phase of the study.

Speed Discrimination: Multiple Stimuli Appear Better Than One

NASA Technical Reports Server (NTRS)

Verghese, Preeti; Stone, Leland S.; Null, Cynthia H. (Technical Monitor)

1995-01-01

We reported that for a 21FC task with multiple moving grating patches (Gabors) in each interval, thresholds for speed discrimination decreased with the number of patches, while increasing the area of a single grating produced no such effect. Furthermore, this decrease occurred regardless of the spacing of the patches about a circle of eccentricity 4 degrees, i.e., whether they were maximally separated or almost touching. These results suggest that it is the multiple, discrete grating patches that cause thresholds to decrease, rather than the spatial arrangement. To test this hypothesis, we measured the effect of dividing a large grating into four quadrants, by superimposing a mean-luminance cross on it. The mean speed discrimination thresholds (Weber Fractions) for four observers were 19, 15, and 11 plus or minus 2%, for the single large grating, the grating with cross, and the 4 maximally-separated, small gratings, respectively. Thus, breaking up a single large grating into multiple parts caused thresholds to improve, despite the fact that less of the original patch was visible. To investigate the possible contribution of total bounding contour length, we measured the effect of coalescing three small grating patches into a single banana-shaped patch, while keeping the total contour length constant. These two conditions were compared to a single, circular Gabor patch of equivalent area that had (necessarily) a smaller contour length. Preliminary data from 3 of 4 observers were similar for the small-grating and banana configurations, but increased for the single, large grating, suggesting that contour length might play a role. We are also investigating the role of low-level factors pertinent to the large grating, such as the pooling of signals from motion units at different eccentricities, and the stimulation of extended inhibitory motion surrounds, as well as the possible contribution of topdown influences that segment the stimulus into distinct objects.

A new mechanism for periodic bursting of the recirculation region in the flow through a sudden expansion in a circular pipe

NASA Astrophysics Data System (ADS)

Lebon, Benoit; Nguyen, Minh Quan; Peixinho, Jorge; Shadloo, Mostafa Safdari; Hadjadj, Abdellah

2018-03-01

We report the results of a combined experimental and numerical study of specific finite-amplitude disturbances for transition to turbulence in the flow through a circular pipe with a sudden expansion. The critical amplitude thresholds for localized turbulent patch downstream of the expansion scale with the Reynolds number with a power law exponent of -2.3 for experiments and -2.8 for simulations. A new mechanism for the periodic bursting of the recirculation region is uncovered where the asymmetric recirculation flow develops a periodic dynamics: a secondary recirculation breaks the symmetry along the pipe wall and bursts into localized turbulence, which travels downstream and relaminarises. Flow visualizations show a simple flow pattern of three waves forming, growing, and bursting.

3D printed microneedles for insulin skin delivery.

PubMed

Pere, Cristiane Patricia Pissinato; Economidou, Sophia N; Lall, Gurprit; Ziraud, Clémentine; Boateng, Joshua S; Alexander, Bruce D; Lamprou, Dimitrios A; Douroumis, Dennis

2018-06-15

In this study, polymeric microneedle patches were fabricated by stereolithography, a 3D printing technique, for the transdermal delivery of insulin. A biocompatible resin was photopolymerized to build pyramid and cone microneedle designs followed by inkjet print coating of insulin formulations. Trehalose, mannitol and xylitol were used as drug carriers with the aim to preserve insulin integrity and stability but also to facilitate rapid release rates. Circular dichroism and Raman analysis demonstrated that all carriers maintained the native form of insulin, with xylitol presenting the best performance. Franz cell release studies were used for in vitro determination of insulin release rates in porcine skin. Insulin was released rapidly within 30 min irrespectively of the microneedle design. 3D printing was proved an effective technology for the fabrication of biocompatible and scalable microneedle patches. Copyright © 2018 Elsevier B.V. All rights reserved.

Evolution of Patterns in Rotating Bénard Convection

NASA Astrophysics Data System (ADS)

Fantz, M.; Friedrich, R.; Bestehorn, M.; Haken, H.

We present an extension of the Swift-Hohenberg equation to the case of a high Prandtl number Bénard experiment in rotating fluid containers. For the case of circular containers we find complex spatio-temporal behaviour at Taylor numbers smaller than the critical one for the onset of the Küppers-Lortz instability. Furthermore, above the critical Taylor number the experimentally well-known time dependent and spatially disordered patterns in form of local patches of rolls are reproduced.

Compact circularly polarized truncated square ring slot antenna with suppressed higher resonances

PubMed Central

Sabran, Mursyidul Idzam; Leow, Chee Yen; Soh, Ping Jack; Chew, Beng Wah; Vandenbosch, Guy A. E.

2017-01-01

This paper presents a compact circularly polarized (CP) antenna with an integrated higher order harmonic rejection filter. The proposed design operates within the ISM band of 2.32 GHz– 2.63 GHz and is suitable for example for wireless power transfer applications. Asymmetrical truncated edges on a square ring create a defected ground structure to excite the CP property, simultaneously realizing compactness. It offers a 50.5% reduced patch area compared to a conventional design. Novel stubs and slot shapes are integrated in the transmission line to reduce higher (up to the third) order harmonics. The proposed prototype yields a -10 dB reflection coefficient (S11) impedance bandwidth of 12.53%, a 3 dB axial ratio bandwidth of 3.27%, and a gain of 5.64 dBi. Measurements also show good agreement with simulations. PMID:28192504

Omnidirectional, circularly polarized, cylindrical microstrip antenna

NASA Technical Reports Server (NTRS)

Stanton, Philip H. (Inventor)

1985-01-01

A microstrip cylindrical antenna comprised of two concentric subelements on a ground cylinder, a vertically polarized (E-field parallel to the axis of the antenna cylinder) subelement on the inside and a horizontally polarized (E-field perpendicular to the axis) subelement on the outside. The vertical subelement is a wraparound microstrip radiator. A Y-shaped microstrip patch configuration is used for the horizontally polarized radiator that is wrapped 1.5 times to provide radiating edges on opposite sides of the cylindrical antenna for improved azimuthal pattern uniformity. When these subelements are so fed that their far fields are equal in amplitude and phased 90.degree. from each other, a circularly polarized EM wave results. By stacking a plurality of like antenna elements on the ground cylinder, a linear phased array antenna is provided that can be beam steered to the desired elevation angle.

Compact circularly polarized truncated square ring slot antenna with suppressed higher resonances.

PubMed

Sabran, Mursyidul Idzam; Abdul Rahim, Sharul Kamal; Leow, Chee Yen; Soh, Ping Jack; Chew, Beng Wah; Vandenbosch, Guy A E

2017-01-01

This paper presents a compact circularly polarized (CP) antenna with an integrated higher order harmonic rejection filter. The proposed design operates within the ISM band of 2.32 GHz- 2.63 GHz and is suitable for example for wireless power transfer applications. Asymmetrical truncated edges on a square ring create a defected ground structure to excite the CP property, simultaneously realizing compactness. It offers a 50.5% reduced patch area compared to a conventional design. Novel stubs and slot shapes are integrated in the transmission line to reduce higher (up to the third) order harmonics. The proposed prototype yields a -10 dB reflection coefficient (S11) impedance bandwidth of 12.53%, a 3 dB axial ratio bandwidth of 3.27%, and a gain of 5.64 dBi. Measurements also show good agreement with simulations.

Multisclae heterogeneity of the 2011 Tohoku-oki earthquake by inversion

NASA Astrophysics Data System (ADS)

Aochi, H.; Ulrich, T.; Cornier, G.

2012-12-01

Earthquake fault heterogeneity is often studied on a set of subfaults in kinematic inversion, while it is sometimes described with spatially localized geometry. Aochi and Ide (EPS, 2011) and Ide and Aochi (submitted to Pageoph and AGU, 2012) apply a concept of multi-scale heterogeneity to simulate the dynamic rupture process of the 2011 Tohoku-oki earthquake, introducing circular patches of different dimension in fault fracture energy distribution. Previously the patches are given by the past moderate earthquakes in this region, and this seems to be consistent with the evolution process of this mega earthquake, although a few patches, in particular, the largest patch, had not been known previously. In this study, we try to identify patches by inversion. As demonstrated in several earthquakes including the 2010 Maule (M8.8) earthquake, it is possible to indentify two asperities of ellipse kinematically or dynamically (e.g. Ruiz and Madariaga, 2011, and so on). In the successful examples, different asperities are rather visible, separated in space. However the Tohoku-oki earthquake has hierarchical structure of heterogeneity. We apply the Genetic Algorithm to inverse the model parameters from the ground motions (K-net and Kik-net from NIED) and the high sampling GPS (GSI). Starting from low frequency ranges (> 50 seconds), we obtain an ellipse corresponding to M9 event located around the hypocenter, coherent with the previous result by Madariaga et al. (pers. comm.). However it is difficult to identify the second smaller with few constraints. This is mainly because the largest covers the entire rupture area and any smaller patch improves the fitting only for the closer stations. Again, this needs to introduce the multi-scale concept in inversion procedure. Instead of finding the largest one at first, we have to start to extract rather smaller moderate patches from the beginning of the record, following the rupture process.

Variability of Slip Behavior in Simulations of Dynamic Rupture Interaction With Stronger Fault Patches Over Long-Term Deformation Histories

NASA Astrophysics Data System (ADS)

Lapusta, N.; Liu, Y.

2007-12-01

Heterogeneity in fault properties can have significant effect on dynamic rupture propagation and aseismic slip. It is often assumed that a fixed heterogeneity would have similar effect on fault slip throughout the slip history. We investigate dynamic rupture interaction with a fault patch of higher normal stress over several earthquake cycles in a three-dimensional model. We find that the influence of the heterogeneity on dynamic events has significant variation and depends on prior slip history. We consider a planar strike-slip fault governed by rate and state friction and driven by slow tectonic loading on deeper extension of the fault. The 30 km by 12 km velocity-weakening region, which is potentially seismogenic, is surrounded by steady-state velocity-strengthening region. The normal stress is constant over the fault, except in a circular patch of 2 km in diameter located in the seismogenic region, where normal stress is higher than on the rest of the fault. Our simulations employ the methodology developed by Lapusta and Liu (AGU, 2006), which is able to resolve both dynamic and quasi-static stages of spontaneous slip accumulation in a single computational procedure. The initial shear stress is constant on the fault, except in a small area where it is higher and where the first large dynamic event initiates. For patches with 20%, 40%, 60% higher normal stress, the first event has significant dynamic interaction with the patch, creating a rupture speed decrease followed by a supershear burst and larger slip around the patch. Hence, in the first event, the patch acts as a seismic asperity. For the case of 100% higher stress, the rupture is not able to break the patch in the first event. In subsequent dynamic events, the behavior depends on the strength of heterogeneity. For the patch with 20% higher normal stress, dynamic rupture in subsequent events propagates through the patch without any noticeable perturbation in rupture speed or slip. In particular, supershear propagation and additional slip accumulation around the patch are never repeated in the simulated history of the fault, and the patch stops manifesting itself as a seismic asperity. This is due to higher shear stress that is established at the patch after the first earthquake cycle. For patches with higher normal stress, shear stress redistribution also occurs, but it is less effective. The patches with 40% and 60% higher normal stress continue to affect rupture speed and fault slip in some of subsequent events, although the effect is much diminished with respect to the first event. For example, there are no supershear bursts. The patch with 100% higher normal stress is first broken in the second large event, and it retains significant influence on rupture speed and slip throughout the fault history, occasionally resulting in supershear bursts. Additional slip complexity emerges for patches with 40% and higher normal stress contrast. Since higher normal stress corresponds to a smaller nucleation size, nucleation of some events moves from the rheological transitions (where nucleation occurs in the cases with no stronger patch and with the patch of 20% higher normal stress) to the patches of higher normal stress. The patches nucleate both large, model-spanning, events, and small events that arrest soon after exiting the patch. Hence not every event that originates at the location of a potential seismic asperity is destined to be large, as its subsequent propagation is significantly influenced by the state of stress outside the patch.

Simple Patchy-Based Simulators Used to Explore Pondscape Systematic Dynamics

PubMed Central

Fang, Wei-Ta; Chou, Jui-Yu; Lu, Shiau-Yun

2014-01-01

Thousands of farm ponds disappeared on the tableland in Taoyuan County, Taiwan since 1920s. The number of farm ponds that have disappeared is 1,895 (37%), 2,667 ponds remain (52%), and only 537 (11%) new ponds were created within a 757 km2 area in Taoyuan, Taiwan between 1926 and 1960. In this study, a geographic information system (GIS) and logistic stepwise regression model were used to detect pond-loss rates and to understand the driving forces behind pondscape changes. The logistic stepwise regression model was used to develop a series of relationships between pondscapes affected by intrinsic driving forces (patch size, perimeter, and patch shape) and external driving forces (distance from the edge of the ponds to the edges of roads, rivers, and canals). The authors concluded that the loss of ponds was caused by pond intrinsic factors, such as pond perimeter; a large perimeter increases the chances of pond loss, but also increases the possibility of creating new ponds. However, a large perimeter is closely associated with circular shapes (lower value of the mean pond-patch fractal dimension [MPFD]), which characterize the majority of newly created ponds. The method used in this study might be helpful to those seeking to protect this unique landscape by enabling the monitoring of patch-loss problems by using simple patchy-based simulators. PMID:24466281

A Study of Microwave and Millimeter-Wave Quasi-Optical Planar Mixers.

DTIC Science & Technology

1983-08-31

reasons of symmetry a mode is not excited at all, N goes to infinity and the series impedance at the primary vanishes. Determining the impedance...taken from Araki and Itoh (1]. The primary aim of their work was to calculate the resonanc frequency of a -, circular microstrip patch antenna. They...T11 ALLEVIATE THIS# A TRAO IS PLACED TO SIIUNTITUTE * THE SMALL-ARGUNENT APPftVINATIfI% To THE FUCTION 0WHeW * ARP.I’PRIATE. THE FPLLfljI IF STATENENT

Fire reinforces structure of pondcypress (Taxodium distichum var. imbricarium) domes in a wetland landscape

USGS Publications Warehouse

Watts, Adam C.; Kobziar, Leda N.; Snyder, James R.

2012-01-01

Fire periodically affects wetland forests, particularly in landscapes with extensive fire-prone uplands. Rare occurrence and difficulty of access have limited efforts to understand impacts of wildfires fires in wetlands. Following a 2009 wildfire, we measured tree mortality and structural changes in wetland forest patches. Centers of these circular landscape features experienced lower fire severity, although no continuous patch-size or edge effect was evident. Initial survival of the dominant tree, pondcypress (Taxodium distichum var. imbricarium), was high (>99%), but within one year of the fire approximately 23% of trees died. Delayed mortality was correlated with fire severity, but unrelated to other hypothesized factors such as patch size or edge distance. Tree diameter and soil elevation were important predictors of mortality, with smaller trees and those in areas with lower elevation more likely to die following severe fire. Depressional cypress forests typically exhibit increasing tree size towards their interiors, and differential mortality patterns were related to edge distance. These patterns result in the exaggeration of a dome-shaped profile. Our observations quantify roles of fire and hydrology in determining cypress mortality in these swamps, and imply the existence of feedbacks that maintain the characteristic shape of cypress domes.

Effect of wettability and topological features of Namib beetle inspired bumps on dropwise condensation

NASA Astrophysics Data System (ADS)

Ahmad, Shakeel; Tang, Hui; Yao, Haimin

2017-11-01

The Stenocara beetle lives in arid desert environment where the only available source of water is fog droplets. The beetle contains many hydrophobic/hydrophilic bumps on its back. Water collection occurs on the hydrophilic patches. Once the droplet reaches the critical volume, it sheds down due to gravity. Although a number of studies on condensation and water collection on beetle inspired structures have been reported in literature, most of them were on micro/nano scale textures. However, in nature the beetle bumps are in millimeter scale. At this scale the role of topological features and gravity becomes crucial for early droplet shedding. Therefore, in this work we numerically investigated the effects of bump shape, wettability contrast, surface slope and hydrophilic patch to total area ratio on droplet shedding volume and time. A three-dimensional lattice Boltzmann method (LBM) based numerical framework was used for the simulations. Compared with bumps of other shapes such a cube or a circular cylinder, faster droplet shedding was obtained over a hemispherical bump. Furthermore, it was found that larger hydrophilic patch to total area ratio for the hemispherical bump significantly increased the droplet shedding time.

Arc Welding of Mg Alloys: Oxide Films, Irregular Weld Shape and Liquation Cracking

NASA Astrophysics Data System (ADS)

Chai, Xiao

The use of Mg alloys for vehicle weight reduction has been increasing rapidly worldwide. Gas-metal arc welding (GMAW) has the potential for mass-production welding of Mg alloys. Recently, the University of Wisconsin demonstrated in bead-on-plate GMAW of Mg alloys that severe spatter can be eliminated by using controlled short circuiting (CSC), and severe hydrogen porosity can be eliminated by removing Mg(OH)2. The present study aimed at actual butt and lap welding of Mg alloys by CSC-GMAW and susceptibility of Mg alloys to weld-edge cracking using the circular-patch welding test. Sound welds were made without spatter and hydrogen porosity butt and lap welding of AZ 31 Mg using CSC-GMAW , with butt welds approaching 100% of the base-metal strength. However, three new significant issues were found to occur easily and degrade the weld quality significantly: 1. formation of oxide films inside butt welds, 2. formation of high crowns on butt welds, and 3. formation of fingers from lap welds. The mechanisms of their formation were established, and the methods for their elimination or reduction were demonstrated. Circular-patch welds were made on most widely used Mg casting alloy AZ91, the most widely used Mg wrought alloy AZ31 with three different Mg filler wires AZ31, AZ61 and AZ92. The susceptibility to cracking along the weld edge was predicted and compared against the experimental results. Such a prediction has not been made for welds of Mg alloys before.

A CPW-fed circular wide-slot UWB antenna with wide tunable and flexible reconfigurable dual notch bands.

PubMed

Li, Yingsong; Li, Wenxing; Ye, Qiubo

2013-01-01

A coplanar waveguide (CPW)-fed circular slot antenna with wide tunable dual band-notched function and frequency reconfigurable characteristic is designed, and its performance is verified experimentally for ultra-wideband (UWB) communication applications. The dual band-notched function is achieved by using a T-shaped stepped impedance resonator (T-SIR) inserted inside the circular ring radiation patch and by etching a parallel stub loaded resonator (PSLR) in the CPW transmission line, while the wide tunable bands can be implemented by adjusting the dimensions of the T-SIR and the PSLR. The notch band reconfigurable characteristic is realized by integrating three switches into the T-SIR and the PSLR. The numerical and experimental results show that the proposed antenna has a wide bandwidth ranging from 2.7 GHz to 12 GHz with voltage standing wave ratio (VSWR) less than 2, except for the two notch bands operating at 3.8-5.9 GHz and 7.7-9.2 GHz, respectively. In addition, the proposed antenna has been optimized to a compact size and can provide omnidirectional radiation patterns, which are suitable for UWB communication applications.

A CPW-Fed Circular Wide-Slot UWB Antenna with Wide Tunable and Flexible Reconfigurable Dual Notch Bands

PubMed Central

Li, Yingsong; Li, Wenxing; Ye, Qiubo

2013-01-01

A coplanar waveguide (CPW)-fed circular slot antenna with wide tunable dual band-notched function and frequency reconfigurable characteristic is designed, and its performance is verified experimentally for ultra-wideband (UWB) communication applications. The dual band-notched function is achieved by using a T-shaped stepped impedance resonator (T-SIR) inserted inside the circular ring radiation patch and by etching a parallel stub loaded resonator (PSLR) in the CPW transmission line, while the wide tunable bands can be implemented by adjusting the dimensions of the T-SIR and the PSLR. The notch band reconfigurable characteristic is realized by integrating three switches into the T-SIR and the PSLR. The numerical and experimental results show that the proposed antenna has a wide bandwidth ranging from 2.7 GHz to 12 GHz with voltage standing wave ratio (VSWR) less than 2, except for the two notch bands operating at 3.8–5.9 GHz and 7.7–9.2 GHz, respectively. In addition, the proposed antenna has been optimized to a compact size and can provide omnidirectional radiation patterns, which are suitable for UWB communication applications. PMID:24222733

Highly efficient multifunctional metasurface for high-gain lens antenna application

NASA Astrophysics Data System (ADS)

Hou, Haisheng; Wang, Guangming; Li, Haipeng; Guo, Wenlong; Li, Tangjing

2017-07-01

In this paper, a novel multifunctional metasurface combining linear-to-circular polarization conversion and electromagnetic waves focusing has been proposed and applied to design a high-gain lens antenna working at Ku band. The multifunctional metasurface consists of 15 × 15 unit cells. Each unit cell is composed of four identical metallic layers and three intermediate dielectric layers. Due to well optimization, the multifunctional metasurface can convert the linearly polarized waves generated by the source to circularly polarized waves and focus the waves. By placing a patch antenna operating at 15 GHz at the focal point of the metasurface and setting the focal distance to diameter ratio ( F/ D) to 0.34, we obtain a multifunctional lens antenna. Simulated and measured results coincide well, indicating that the metasurface can convert linearly polarized waves to right-handed circularly polarized waves at 15 GHz with excellent performances in terms of the 3 dB axial ratio bandwidth of 5.3%, realized gain of 16.9 dB and aperture efficiency of 41.2%. Because of the advantages of high gain, competitive efficiency and easy fabrication, the proposed lens antenna has a great potential application in wireless and satellite communication.

Damage Assessment of Composite Structures Using Digital Image Correlation

NASA Astrophysics Data System (ADS)

Caminero, M. A.; Lopez-Pedrosa, M.; Pinna, C.; Soutis, C.

2014-02-01

The steady increase of Carbon-Fiber Reinforced Polymer (CFRP) Structures in modern aircraft will reach a new dimension with the entry into service of the Boeing 787 and Airbus 350. Replacement of damaged parts will not be a preferable solution due to the high level of integration and the large size of the components involved. Consequently the need to develop repair techniques and processes for composite components is readily apparent. Bonded patch repair technologies provide an alternative to mechanically fastened repairs with significantly higher performance, especially for relatively thin skins. Carefully designed adhesively bonded patches can lead to cost effective and highly efficient repairs in comparison with conventional riveted patch repairs that cut fibers and introduce highly strained regions. In this work, the assessment of the damage process taking place in notched (open-hole) specimens under uniaxial tensile loading was studied. Two-dimensional (2D) and three-dimensional (3D) Digital Image Correlation (DIC) techniques were employed to obtain full-field surface strain measurements in carbon-fiber/epoxy T700/M21 composite plates with different stacking sequences in the presence of an open circular hole. Penetrant enhanced X-ray radiographs were taken to identify damage location and extent after loading around the hole. DIC strain fields were compared to finite element predictions. In addition, DIC techniques were used to characterise damage and performance of adhesively bonded patch repairs in composite panels under tensile loading. This part of work relates to strength/stiffness restoration of damaged composite aircraft that becomes more important as composites are used more extensively in the construction of modern jet airliners. The behaviour of bonded patches under loading was monitored using DIC full-field strain measurements. Location and extent of damage identified by X-ray radiography correlates well with DIC strain results giving confidence to the technique for structural health monitoring of bonded patches.

Vibration suppression with approximate finite dimensional compensators for distributed systems: Computational methods and experimental results

NASA Technical Reports Server (NTRS)

Banks, H. T.; Smith, Ralph C.; Wang, Yun

1994-01-01

Based on a distributed parameter model for vibrations, an approximate finite dimensional dynamic compensator is designed to suppress vibrations (multiple modes with a broad band of frequencies) of a circular plate with Kelvin-Voigt damping and clamped boundary conditions. The control is realized via piezoceramic patches bonded to the plate and is calculated from information available from several pointwise observed state variables. Examples from computational studies as well as use in laboratory experiments are presented to demonstrate the effectiveness of this design.

Rod-cone interaction in light adaptation

PubMed Central

Latch, M.; Lennie, P.

1977-01-01

1. The increment-threshold for a small test spot in the peripheral visual field was measured against backgrounds that were red or blue. 2. When the background was a large uniform field, threshold over most of the scotopic range depended exactly upon the background's effect upon rods. This confirms Flamant & Stiles (1948). But when the background was small, threshold was elevated more by a long wave-length than a short wave-length background equated for its effect on rods. 3. The influence of cones was explored in a further experiment. The scotopic increment-threshold was established for a short wave-length test spot on a large, short wave-length background. Then a steady red circular patch, conspicuous to cones, but below the increment-threshold for rod vision, was added to the background. When it was small, but not when it was large, this patch substantially raised the threshold for the test. 4. When a similar experiment was made using, instead of a red patch, a short wave-length one that was conspicuous in rod vision, threshold varied similarly with patch size. These results support the notion that the influence of small backgrounds arises in some size-selective mechanism that is indifferent to the receptor system in which visual signals originate. Two corollaries of this hypothesis were tested in further experiments. 5. A small patch was chosen so as to lift scotopic threshold substantially above its level on a uniform field. This threshold elevation persisted for minutes after extinction of the patch, but only when the patch was small. A large patch made bright enough to elevate threshold by as much as the small one gave rise to no corresponding after-effect. 6. Increment-thresholds for a small red test spot, detected through cones, followed the same course whether a large uniform background was long- or short wave-length. When the background was small, threshold upon the short wave-length one began to rise for much lower levels of background illumination, suggesting the influence of rods. This was confirmed by repeating the experiment after a strong bleach when the cones, but not rods, had fully recovered their sensitivity. Increment-thresholds upon small backgrounds of long or short wave-lengths then followed the same course. PMID:894602

Monopolar vortices as relative equilibria and their dissipative decay

NASA Astrophysics Data System (ADS)

Vandefliert, B. W.; Vangroesen, E. W. C.

1991-11-01

Families of confined rotating monopolar vortices are characterized using a variational formulation with the angular momentum as the driving force for confinement. The characterization for positive monopolar vortices given, can be extended to negative vortices or to vortices within a rotating frame of reference. Besides the uniform Kirchhoff paths, new branches of vorticity solutions are found restricting the dynamics to levelsets of both the angular momentum and the quadratic anisotropy. The rotation rate of the smooth vorticity structures depends on the vorticity profile. This is made perceptible by considering both minimum energy vortices and minimizing vortices, rotating counterclockwise and clockwise respectively. An approximation for the decay of the vortices due to dissipation is given in terms of the dissipation of the integrals in the inviscid system. This description enables us to consider dissipation of vortices without loss of confinement. The elliptical Kirchhoff patches are found to symmetrize into circular patches. The minimum energy vortices gradually diminish while expending their support, while the maximum energy vortices are unstable for the dissipative evolution.

Antennas for mobile satellite communications

NASA Technical Reports Server (NTRS)

Huang, John

1991-01-01

A NASA sponsored program, called the Mobile Satellite (MSAT) system, has prompted the development of several innovative antennas at L-band frequencies. In the space segment of the MSAT system, an efficient, light weight, circularly polarized microstrip array that uses linearly polarized elements was developed as a multiple beam reflector feed system. In the ground segment, a low-cost, low-profile, and very efficient microstrip Yagi array was developed as a medium-gain mechanically steered vehicle antenna. Circularly shaped microstrip patches excited at higher-order modes were also developed as low-gain vehicle antennas. A more recent effort called for the development of a 20/30 GHz mobile terminal antenna for future-generation mobile satellite communications. To combat the high insertion loss encountered at 20/30 GHz, series-fed Monolithic Microwave Integrated Circuit (MMIC) microstrip array antennas are currently being developed. These MMIC arrays may lead to the development of several small but high-gain Ka-band antennas for the Personal Access Satellite Service planned for the 2000s.

A new design of an S/X dual band circular slot antenna for radar applications.

PubMed

Ghnimi, Said; Wali, Rawia; Gharsallh, Ali; Razban, Tchanguiz

2013-01-01

A novel design of dual-band slot antenna with a circular patch for radar applications is presented and studied. It is fed by a micro-strip line and built on a FR-4 substrate with a whole size of 18 x 30 mm2. A dual band printed antenna is created by introducing slots on the radiating element. By this, two bandwidth, covering C and X band, are achieved. In order to obtain a good fundamental antenna design, the initial studies were carried out theoretically, using CST Microwave Studio simulation software. In this case, the frequency range at return loss < 10 dB is 5.24 - 6.16 GHz for low frequency and is 7.9 -11.7 GHz for high frequency. In addition, the proposed antenna has good radiation characteristics and stable gains over the whole operating bands. A prototype of antenna is fabricated and tested. Experimental data show good agreement between simulated and measured results.

User manual for EXCALIBUR: A FE-BI numerical laboratory for cavity-backed antennas in a circular cylinder, version 1.2

NASA Technical Reports Server (NTRS)

Kempel, Leo C.

1994-01-01

The Finite Element-Boundary Integral (FE-BI) technique was used to analyze the scattering and radiation properties of cavity-backed patch antennas recessed in a metallic groundplane. A program, CAVITY3D, was written and found to yield accurate results for large arrays without the usual high memory and computational demand associated with competing formulations. Recently, the FE-BI approach was extended to cavity-backed antennas recessed in an infinite, metallic circular cylinder. EXCALIBUR is a computer program written in the Radiation Laboratory of the University of Michigan which implements this formulation. This user manual gives a brief introduction to EXCALIBUR and some hints as to its proper use. As with all computational electromagnetics programs (especially finite element programs), skilled use and best performance are only obtained through experience. However, several important aspects of the program such as portability, geometry generation, interpretation of results, and custom modification are addressed.

Photos of earth observations taken by JPL with the Shuttle Imaging Radar-A

NASA Technical Reports Server (NTRS)

1981-01-01

Photos of earth observations taken by the Jet Propulsion Laboratory (JPL) with the Shuttle Imaging Radar-A (SIR-A). The first image show northern Peloponnesia and part of southern Greece. The Corinthian Canal is visible as a bright line cutting across the narrow Corinth Isthmus (upper center). Black area to the right is the Aegian Sea; on the left, the Gulf of Corinth. Islands to the right, starting at the top, are Salamis, Aegene and Angistrion, and the Peninsula of Methana. Southwest of the canal on the gulf coast is the city of Corinth, appearing as bright, white spots (40244); This image shows the Hamersley mountain range in Western Australia. A circular pattern of eroded folds surround a prominent granite dome, remnants of a volcanic past, is seen in the center of the photograph. The Hardey River is seen running vertically to the right of the center circular dome, and the small town of Paraburdoo appears as a patch of tiny bright rectangles in the lower right corner (40245).

EIT-based fabric pressure sensing.

PubMed

Yao, A; Yang, C L; Seo, J K; Soleimani, M

2013-01-01

This paper presents EIT-based fabric sensors that aim to provide a pressure mapping using the current carrying and voltage sensing electrodes attached to the boundary of the fabric patch. Pressure-induced shape change over the sensor area makes a change in the conductivity distribution which can be conveyed to the change of boundary current-voltage data. This boundary data is obtained through electrode measurements in EIT system. The corresponding inverse problem is to reconstruct the pressure and deformation map from the relationship between the applied current and the measured voltage on the fabric boundary. Taking advantage of EIT in providing dynamical images of conductivity changes due to pressure induced shape change, the pressure map can be estimated. In this paper, the EIT-based fabric sensor was presented for circular and rectangular sensor geometry. A stretch sensitive fabric was used in circular sensor with 16 electrodes and a pressure sensitive fabric was used in a rectangular sensor with 32 electrodes. A preliminary human test was carried out with the rectangular sensor for foot pressure mapping showing promising results.

A complete system for 3D reconstruction of roots for phenotypic analysis.

PubMed

Kumar, Pankaj; Cai, Jinhai; Miklavcic, Stanley J

2015-01-01

Here we present a complete system for 3D reconstruction of roots grown in a transparent gel medium or washed and suspended in water. The system is capable of being fully automated as it is self calibrating. The system starts with detection of root tips in root images from an image sequence generated by a turntable motion. Root tips are detected using the statistics of Zernike moments on image patches centred on high curvature points on root boundary and Bayes classification rule. The detected root tips are tracked in the image sequence using a multi-target tracking algorithm. Conics are fitted to the root tip trajectories using a novel ellipse fitting algorithm which weighs the data points by its eccentricity. The conics projected from the circular trajectory have a complex conjugate intersection which are image of the circular points. Circular points constraint the image of the absolute conics which are directly related to the internal parameters of the camera. The pose of the camera is computed from the image of the rotation axis and the horizon. The silhouettes of the roots and camera parameters are used to reconstruction the 3D voxel model of the roots. We show the results of real 3D reconstruction of roots which are detailed and realistic for phenotypic analysis.

Microstrip Patch Antenna And Method

NASA Technical Reports Server (NTRS)

Fink, Patrick W. (Inventor)

2001-01-01

Method and apparatus are provided for a microstrip feeder structure for supplying properly phased signals to each radiator element in a microstrip antenna array that may be utilized for radiating circularly polarized electromagnetic waves. In one disclosed embodiment. the microstrip feeder structure includes a plurality of microstrip sections many or all of which preferably have an electrical length substantially equal to one-quarter wavelength at the antenna operating frequency. The feeder structure provides a low loss feed structure that may be duplicated multiple times through a set of rotations and translations to provide a radiating array of the desired size.

The LeucoPatch® system in the management of hard-to-heal diabetic foot ulcers: study protocol for a randomised controlled trial.

PubMed

Game, Frances; Jeffcoate, William; Tarnow, Lise; Day, Florence; Fitzsimmons, Deborah; Jacobsen, Judith

2017-10-10

Diabetic foot ulcers are a common and severe complication of diabetes mellitus. Standard treatment includes debridement, offloading, management of infection and revascularisation where appropriate, although healing times may be long. The LeucoPatch® device is used to generate an autologous platelet-rich fibrin and leucocyte wound dressing produced from the patient's own venous blood by centrifugation, but without the addition of any reagents. The final product comprises a thin, circular patch composed predominantly of fibrin together with living platelets and leucocytes. Promising results have been obtained in non-controlled studies this system, but this now needs to be tested in a randomised controlled trial (RCT). If confirmed, the LeucoPatch® may become an important new tool in the armamentarium in the management of diabetic foot ulcers which are hard-to-heal. People with diabetes and hard-to-heal ulcers of the foot will receive either pre-specified good standard care or good standard care supplemented by the application of the LeucoPatch® device. The primary outcome will be the percentage of ulcers healed within 20 weeks. Healing will be defined as complete epithelialisation without discharge that is maintained for 4 weeks and is confirmed by an observer blind to randomisation group. Ulcers of the foot are a major source of morbidity to patients with diabetes and costs to health care economies. The study population is designed to be as inclusive as possible with the aim of maximising the external validity of any findings. The primary outcome measure is healing within 20 weeks of randomisation and the trial also includes a number of secondary outcome measures. Among these are rate of change in ulcer area as a predictor of the likelihood of eventual healing, minor and major amputation of the target limb, the incidence of infection and quality of life. International Standard Randomised Controlled Trial, ISRCTN27665670 . Registered on 5 July 2013.

Contrast effects on speed perception for linear and radial motion.

PubMed

Champion, Rebecca A; Warren, Paul A

2017-11-01

Speed perception is vital for safe activity in the environment. However, considerable evidence suggests that perceived speed changes as a function of stimulus contrast, with some investigators suggesting that this might have meaningful real-world consequences (e.g. driving in fog). In the present study we investigate whether the neural effects of contrast on speed perception occur at the level of local or global motion processing. To do this we examine both speed discrimination thresholds and contrast-dependent speed perception for two global motion configurations that have matched local spatio-temporal structure. Specifically we compare linear and radial configurations, the latter of which arises very commonly due to self-movement. In experiment 1 the stimuli comprised circular grating patches. In experiment 2, to match stimuli even more closely, motion was presented in multiple local Gabor patches equidistant from central fixation. Each patch contained identical linear motion but the global configuration was either consistent with linear or radial motion. In both experiments 1 and 2, discrimination thresholds and contrast-induced speed biases were similar in linear and radial conditions. These results suggest that contrast-based speed effects occur only at the level of local motion processing, irrespective of global structure. This result is interpreted in the context of previous models of speed perception and evidence suggesting differences in perceived speed of locally matched linear and radial stimuli. Copyright © 2017 Elsevier Ltd. All rights reserved.

A hydrophobic patch surrounding Trp154 in human neuroserpin controls the helix F dynamics with implications in inhibition and aggregation

NASA Astrophysics Data System (ADS)

Ali, Mohammad Farhan; Kaushik, Abhinav; Kapil, Charu; Gupta, Dinesh; Jairajpuri, Mohamad Aman

2017-02-01

Neuroserpin (NS) mediated inhibition of tissue-type plasminogen activator (tPA) is important for brain development, synapse formation and memory. Aberrations in helix F and β-sheet A movement during inhibition can directly lead to epilepsy or dementia. Conserved W154 residue in a hydrophobic patch between helix F and β-sheet A is ideally placed to control their movement during inhibition. Molecular Dynamics (MD) simulation on wild type (WT) NS and its two variants (W154A and W154P) demonstrated partial deformation in helix F and conformational differences in strands 1A and 2A only in W154P. A fluorescence and Circular Dichroism (CD) analysis with purified W154 variants revealed a significant red-shift and an increase in α-helical content in W154P as compared to W154A and WT NS. Kinetics of tPA inhibition showed a decline in association rates (ka) for W154A as compared to WT NS with indication of complex formation. Appearance of cleaved without complex formation in W154P indicates that the variant acts as substrate due to conformational misfolding around helix F. Both the variants however showed increased rate of aggregation as compared to WT NS. The hydrophobic patch identified in this study may have importance in helix F dynamics of NS.

Vortex Design Problem

NASA Astrophysics Data System (ADS)

Protas, Bartosz

2007-11-01

In this investigation we are concerned with a family of solutions of the 2D steady--state Euler equations, known as the Prandtl--Batchelor flows, which are characterized by the presence of finite--area vortex patches embedded in an irrotational flow. We are interested in flows in the exterior of a circular cylinder and with a uniform stream at infinity, since such flows are often employed as models of bluff body wakes in the high--Reynolds number limit. The ``vortex design'' problem we consider consists in determining a distribution of the wall--normal velocity on parts of the cylinder boundary such that the vortex patches modelling the wake vortices will have a prescribed shape and location. Such inverse problem have applications in various areas of flow control, such as mitigation of the wake hazard. We show how this problem can be solved computationally by formulating it as a free--boundary optimization problem. In particular, we demonstrate that derivation of the adjoint system, required to compute the cost functional gradient, is facilitated by application of the shape differential calculus. Finally, solutions of the vortex design problem are illustrated with computational examples.

A Simple Ultra-Wideband Magneto-Electric Dipole Antenna With High Gain

NASA Astrophysics Data System (ADS)

Shuai, Chen-yang; Wang, Guang-ming

2017-12-01

A simple ultra-wideband magneto-electric dipole antenna utilizing a differential-fed structure is designed. The antenna mainly comprises three parts, including a novel circular horned reflector, two vertical semicircular shorted patches as a magnetic dipole, and a horizontal U-shaped semicircular electric dipole. A differential feeding structure working as a perfect balun excites the designed antenna. The results of simulation have a good match with the ones of measurement. Results indicate that the designed antenna achieves a wide frequency bandwidth of 107 % which is 3.19 10.61 GHz, when VSWR is below 2. Via introducing the circular horned reflector, the designed antenna attains a steady and high gain of 12±1.5dBi. Moreover, settled broadside direction main beam, high front-to-back ratio, low cross polarization, and the symmetrical and relatively stable radiation patterns in the E-and H-plane are gotten in the impedance bandwidth range. In the practical applications, the proposed antenna that is dc grounded and has a simple structure satisfies the requirement of many outdoor antennas.

Circular Microstrip Antenna with Fractal Slots for Multiband Applications

NASA Astrophysics Data System (ADS)

Singh, Sivia Jagtar; Singh, Gurpreet; Bharti, Gurpreet

2017-10-01

In this paper, a multiband, fractal, slotted, Circular Microstrip Patch Antenna for GSM, WiMAX, C and X bands (satellite communication applications) is presented. A cantor set theory is used to make fractal slots for obtaining the desired multiband. The projected antenna is simulated using Ansys HFSS v13.0 software. Simulation test of this antenna has been carried out for a frequency range of 1 GHz-10 GHz and a peak gain of 9.19 dB at a resonance frequency of 1.9 GHz is obtained. The antenna also resonates at 3.7 GHz, 6.06 GHz and 7.9 GHz with gains of 3.04 dB, 5.19 dB and 5.39 dB respectively. Parameters like voltage standing wave ratio, return loss, and gain are used to compare the results of the projected antenna with conventional CMPA's of same dimensions with full and defective grounds. The projected antenna is fabricated on a glass epoxy material and is tested using Vector Network Analyzer. The performance parameters of the antenna are found to in good agreement with each both using simulated and measured data.

EIT-Based Fabric Pressure Sensing

PubMed Central

Yao, A.; Yang, C. L.; Seo, J. K.; Soleimani, M.

2013-01-01

This paper presents EIT-based fabric sensors that aim to provide a pressure mapping using the current carrying and voltage sensing electrodes attached to the boundary of the fabric patch. Pressure-induced shape change over the sensor area makes a change in the conductivity distribution which can be conveyed to the change of boundary current-voltage data. This boundary data is obtained through electrode measurements in EIT system. The corresponding inverse problem is to reconstruct the pressure and deformation map from the relationship between the applied current and the measured voltage on the fabric boundary. Taking advantage of EIT in providing dynamical images of conductivity changes due to pressure induced shape change, the pressure map can be estimated. In this paper, the EIT-based fabric sensor was presented for circular and rectangular sensor geometry. A stretch sensitive fabric was used in circular sensor with 16 electrodes and a pressure sensitive fabric was used in a rectangular sensor with 32 electrodes. A preliminary human test was carried out with the rectangular sensor for foot pressure mapping showing promising results. PMID:23533538

THE FORMATION AND ERUPTION OF A SMALL CIRCULAR FILAMENT DRIVEN BY ROTATING MAGNETIC STRUCTURES IN THE QUIET SUN

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

Yang, Bo; Jiang, Yunchun; Yang, Jiayan

We present the first observation of the formation and eruption of a small circular filament driven by a rotating network magnetic field (RNF) in the quiet Sun. In the negative footpoint region of an inverse J-shaped dextral filament, the RNF was formed by the convergence to supergranular junctions of several magnetic flux patches of the same polarity, and it then rotated counterclockwise (CCW) for approximately 11 hr and showed up as a CCW rotating EUV cyclone, during which time the filament gradually evolved into a circular filament that surrounded the cyclone. When the calculated convergence and vortex flows appeared aroundmore » the RNF during its formation and rotation phases, the injected magnetic helicity calculation also showed negative helicity accumulation during the RNF rotation that was consistent with the dextral chirality of the filament. Finally, the RNF rotation stopped and the cyclone disappeared, and, probably due to an emerging bipole and its forced cancellation with the RNF, the closure filament underwent an eruption along its axis in the (clockwise) direction opposite to the rotation directions of the RNF and cyclone. These observations suggest that the RNFs might play an important role in the formation of nearby small-scale circular filaments as they transport and inject magnetic energy and helicity, and the formation of the EUV cyclones may be a further manifestation of the helicity injected into the corona by the rotation of the RNFs in the photosphere. In addition, the new emerging bipole observed before the filament eruption might be responsible for destabilizing the system and triggering the magnetic reconnection which proves useful for the filament eruption.« less

Polarization optics of the Brewster's dark patch visible on water surfaces versus solar height and sky conditions: theory, computer modeling, photography, and painting.

PubMed

Takács, Péter; Barta, András; Pye, David; Horváth, Gábor

2017-10-20

When the sun is near the horizon, a circular band with approximately vertically polarized skylight is formed at 90° from the sun, and this skylight is only weakly reflected from the region of the water surface around the Brewster's angle (53° from the nadir). Thus, at low solar heights under a clear sky, an extended dark patch is visible on the water surface when one looks toward the north or south quarter perpendicular to the solar vertical. In this work, we study the radiance distribution of this so-called Brewster's dark patch (BDP) in still water as functions of the solar height and sky conditions. We calculate the pattern of reflectivity R of a water surface for a clear sky and obtain from this idealized situation the shape of the BDP. From three full-sky polarimetric pictures taken about a clear, a partly cloudy, and an overcast sky, we determine the R pattern and compose from that synthetic color pictures showing how the radiance distribution of skylight reflected at the water surface and the BDPs would look under these sky conditions. We also present photographs taken without a linearly polarizing filter about the BDP. Finally, we show a 19th century painting on which a river is seen with a dark region of the water surface, which can be interpreted as an artistic illustration of the BDP.

Fires in Kamchatka Peninsula, Russia

NASA Technical Reports Server (NTRS)

2002-01-01

Numerous thermal anomalies were detected on the Kamchatka Peninsula in northeastern Russia in late June and early July by the Moderate Resolution Imaging Spectroradiometer (MODIS). Some of the anomalies (red dots) were fires, but at least one was the result of ongoing volcanic activity at one of the Peninsula's numerous active volcanoes. The erupting volcano, called Sheveluch, can be seen most clearly in the image from July 8, 2002. It is located in the upper right quadrant of the image, and appears as a grayish circular patch amid the surrounding green vegetation. In its center is a red dot indicating that MODIS detected a thermal signature coming from the restless volcano. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

Mars Under the Microscope

NASA Technical Reports Server (NTRS)

2004-01-01

This magnified look at the martian soil near the Mars Exploration Rover Opportunity's landing site, Meridiani Planum, shows coarse grains sprinkled over a fine layer of sand. The image was captured by the rover's microscopic imager on the 10th day, or sol, of its mission. Scientists are intrigued by the spherical rocks, which can be formed by a variety of geologic processes, including cooling of molten lava droplets and accretion of concentric layers of material around a particle or 'seed.'

The examined patch of soil is 3 centimeters (1.2 inches) across. The circular grain in the lower left corner is approximately 3 millimeters (.12 inches) across, or about the size of a sunflower seed.

ARC-1979-A79-7097

NASA Image and Video Library

1979-07-08

Range : 85,000 kilometers (53,000 miles) This photo of Jupiter's satellite Ganymede shows ancient cratered terrain. A variety of impact craters of different ages are shown. The brightest craters are the youngest. The ejecta blankets fade with age. The center shows a bright patch that represents the rebounding of the floor of the crater. The dirty ice has lost all topography except for faint circular patterns. Also shown are the 'Callisto type' curved troughs and ridges that mark an ancient enormous impact basin. The basin itself has been destroyed by later geologic processes. Only the ring features are preserved on the ancient surface. Near the bottom of the picture, these curved features are trumcated by the younger grooved terrain.

Simplified computational methods for elastic and elastic-plastic fracture problems

NASA Technical Reports Server (NTRS)

Atluri, Satya N.

1992-01-01

An overview is given of some of the recent (1984-1991) developments in computational/analytical methods in the mechanics of fractures. Topics covered include analytical solutions for elliptical or circular cracks embedded in isotropic or transversely isotropic solids, with crack faces being subjected to arbitrary tractions; finite element or boundary element alternating methods for two or three dimensional crack problems; a 'direct stiffness' method for stiffened panels with flexible fasteners and with multiple cracks; multiple site damage near a row of fastener holes; an analysis of cracks with bonded repair patches; methods for the generation of weight functions for two and three dimensional crack problems; and domain-integral methods for elastic-plastic or inelastic crack mechanics.

Specific absorption rate analysis of broadband mobile antenna with negative index metamaterial

NASA Astrophysics Data System (ADS)

Alam, Touhidul; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2016-03-01

This paper presents a negative index metamaterial-inspired printed mobile wireless antenna that can support most mobile applications such as GSM, UMTS, Bluetooth and WLAN frequency bands. The antenna consists of a semi-circular patch, a 50Ω microstrip feed line and metamaterial ground plane. The antenna occupies a very small space of 37 × 47 × 0.508 mm3, making it suitable for mobile wireless application. The perceptible novelty shown in this proposed antenna is that reduction of specific absorption rate using the negative index metamaterial ground plane. The proposed antenna reduced 72.11 and 75.53 % of specific absorption rate at 1.8 and 2.4 GHz, respectively.

Radiation and scattering from cylindrically conformal printed antennas. Ph.D. Thesis Final Report

NASA Technical Reports Server (NTRS)

Kempel, Leo C.; Volakis, John L.

1994-01-01

Microstrip patch antennas offer considerable advantages in terms of weight, aerodynamic drag, cost, flexibility, and observables over more conventional protruding antennas. These flat patch antennas were first proposed over thirty years ago by Deschamps in the United States and Gutton and Baisinot in France. Such antennas have been analyzed and developed for planar as well as curved platforms. However, the methods used in these designs employ gross approximations, suffer from extreme computational burden, or require expensive physical experiments. The goal of this thesis is to develop accurate and efficient numerical modeling techniques which represent actual antenna structures mounted on curved surfaces with a high degree of fidelity. In this thesis, the finite element method is extended to cavity-backed conformal antenna arrays embedded in a circular, metallic, infinite cylinder. Both the boundary integral and absorbing boundary mesh closure conditions will be used for terminating the mesh. These two approaches will be contrasted and used to study the scattering and radiation behavior of several useful antenna configurations. An important feature of this study will be to examine the effect of curvature and cavity size on the scattering and radiation properties of wraparound conformal antenna arrays.

Favorable locations for piezo actuators in plates with good control effectiveness and minimal change in system dynamics

NASA Astrophysics Data System (ADS)

Dhuri, K. D.; Seshu, P.

2007-12-01

Placement and sizing of piezo actuators is normally based on control effectiveness. However, retrofitting of piezoelectric actuators alters the inherent stiffness/mass properties of the parent structure. In rotating structures, the additional mass due to piezo patches contributes to the centrifugal stiffening force. The parent structure is originally designed to have a certain natural frequency spectrum in relation to the disturbance excitation. In the event of failure of the active system, the dynamics of the structure with piezos (now rendered passive) will therefore become significant. Thus it will be helpful to determine locations for mounting piezo patches based on minimal natural frequency change yet with good control authority. In this study, a finite element based procedure for plate structures is presented. Favorable locations for mounting piezos based on minimal natural frequency changes are iteratively evolved from an initial configuration wherein the whole plate is covered with piezos. A modal controllability approach has been used for finding piezo mounting locations from a good controllability perspective. The procedure is demonstrated for simply supported square, swept-back, circular and rotating rectangular plates considering the first four modes.

Nonlinear finite element modeling of vibration control of plane rod-type structural members with integrated piezoelectric patches

NASA Astrophysics Data System (ADS)

Chróścielewski, Jacek; Schmidt, Rüdiger; Eremeyev, Victor A.

2018-05-01

This paper addresses modeling and finite element analysis of the transient large-amplitude vibration response of thin rod-type structures (e.g., plane curved beams, arches, ring shells) and its control by integrated piezoelectric layers. A geometrically nonlinear finite beam element for the analysis of piezolaminated structures is developed that is based on the Bernoulli hypothesis and the assumptions of small strains and finite rotations of the normal. The finite element model can be applied to static, stability, and transient analysis of smart structures consisting of a master structure and integrated piezoelectric actuator layers or patches attached to the upper and lower surfaces. Two problems are studied extensively: (i) FE analyses of a clamped semicircular ring shell that has been used as a benchmark problem for linear vibration control in several recent papers are critically reviewed and extended to account for the effects of structural nonlinearity and (ii) a smart circular arch subjected to a hydrostatic pressure load is investigated statically and dynamically in order to study the shift of bifurcation and limit points, eigenfrequencies, and eigenvectors, as well as vibration control for loading conditions which may lead to dynamic loss of stability.

Two Distantly Spaced Basic Patches in the Flexible Domain of Huntingtin-Interacting Protein 1 (HIP1) Are Essential for the Binding of Clathrin Light Chain.

PubMed

Ybe, Joel A; Clegg, Mary E; Illingworth, Melissa; Gonzalez, Claire; Niu, Qian

2009-01-01

The interaction between HIP family proteins (HIP1 and HIP12/1R) and clathrin is fundamental to endocytosis. We used circular dichroism (CD) to study the stability of an HIP1 subfragment (aa468-530) that is splayed open. CD thermal melts show HIP1 468-530 is only stable at low temperatures, but this HIP1 fragment contains a structural unit that does not melt out even at 83°C. We then created HIP1 mutants to probe our hypothesis that a short hydrophobic path in the opened region is the binding site for clathrin light chain. We found that the binding of hub/LCb was sensitive to mutating two distantly separated basic residues (K474 and K494). The basic patches marked by K474 and K494 are conserved in HIP12/1R. The lack of conservation in sla2p (S. cerevisiae), HIP1 from D. melanogaster, and HIP1 homolog ZK370.3 from C. elegans implies the binding of HIP1 and HIP1 homologs to clathrin light chain may be different in these organisms.

Two Distantly Spaced Basic Patches in the Flexible Domain of Huntingtin-Interacting Protein 1 (HIP1) Are Essential for the Binding of Clathrin Light Chain

PubMed Central

Ybe, Joel A.; Clegg, Mary E.; Illingworth, Melissa; Gonzalez, Claire; Niu, Qian

2009-01-01

The interaction between HIP family proteins (HIP1 and HIP12/1R) and clathrin is fundamental to endocytosis. We used circular dichroism (CD) to study the stability of an HIP1 subfragment (aa468-530) that is splayed open. CD thermal melts show HIP1 468-530 is only stable at low temperatures, but this HIP1 fragment contains a structural unit that does not melt out even at 83°C. We then created HIP1 mutants to probe our hypothesis that a short hydrophobic path in the opened region is the binding site for clathrin light chain. We found that the binding of hub/LCb was sensitive to mutating two distantly separated basic residues (K474 and K494). The basic patches marked by K474 and K494 are conserved in HIP12/1R. The lack of conservation in sla2p (S. cerevisiae), HIP1 from D. melanogaster, and HIP1 homolog ZK370.3 from C. elegans implies the binding of HIP1 and HIP1 homologs to clathrin light chain may be different in these organisms. PMID:22820750

A multifunctional solar panel antenna for cube satellites

NASA Astrophysics Data System (ADS)

Fawole, Olutosin C.

The basic cube satellite (CubeSat) is a modern small satellite that has a standard size of about one liter (the 1U CubeSat). Three 1U CubeSats could be stacked to form a 3U CubeSat. Their low-cost, short development time, and ease of deployment make CubeSats popular for space research, geographical information gathering, and communication applications. An antenna is a key part of the CubeSat communication subsystem. Traditionally, antennas used on CubeSats are wrapped-up wire dipole antennas, which are deployed after satellite launch. Another antenna type used on CubeSats is the patch antenna. In addition to their low gain and efficiency, deployable dipole antennas may also fail to deploy on satellite launch. On the other hand, a solid patch antenna will compete for space with solar cells when placed on a CubeSat face, interfering with satellite power generation. Slot antennas are promising alternatives to dipole and patch antennas on CubeSats. When excited, a thin slot aperture etched on a conductive sheet (ground plane) is an efficient bidirectional radiator. This open slot antenna can be backed by a reflector or cavity for unidirectional radiation, and solar cells can be placed in spaces on the ground plane not occupied by the slot. The large surface areas of 3U CubeSats can be exploited for a multifunctional antenna by integrating multiple thin slot radiators, which are backed by a thin cavity on the CubeSat surfaces. Solar cells can then be integrated on the antenna surface. Polarization diversity and frequency diversity improve the overall performance of a communication system. Having a single radiating structure that could provide these diversities is desired. It has been demonstrated that when a probe excites a square cavity with two unequal length crossed-slots, the differential radiation from the two slots combines in the far-field to yield circular polarization. In addition, it has been shown that two equal-length proximal slots, when both fed with a stripline, resonate at a frequency due to their original lengths, and also resonate at a lower frequency due to mutual coupling between the slots, leading to a dual-band operation. The multifunctional antenna designs presented are harmonizations and extensions of these two independent works. In the multifunctional antenna designs presented, multiple slots were etched on a 83 mm x 340 mm two-layer shallow cavity. The slots were laid out on the cavity such when the cavity was excited by a probe at a particular point, the differential radiation from the slots would combine in the far-field to yield Left-Handed Circular Polarization (LHCP). Furthermore, when the cavity was excited by another probe at an opposite point, the slots would produce Right-Handed Circular Polarization (RHCP). In addition, as forethought, these slots were laid out on the cavity such that some slots were close together enough to give Linearly Polarized (LP) dual-band operation when fed with a stripline. This antenna was designed and optimized via computer simulations, fabricated using Printed Circuit Board (PCB) technology, and characterized using a Vector Network Analyzer (VNA) and NSI Far Field Systems.

Aram and Iani Chaos

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-344, 28 April 2003

This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image mosaic was constructed from data acquired by the MOC red wide angle camera. The large, circular feature in the upper left is Aram Chaos, an ancient impact crater filled with layered sedimentary rock that was later disrupted and eroded to form a blocky, 'chaotic' appearance. To the southeast of Aram Chaos, in the lower right of this picture, is Iani Chaos. The light-toned patches amid the large blocks of Iani Chaos are known from higher-resolution MOC images to be layered, sedimentary rock outcrops. The picture center is near 0.5oN, 20oW. Sunlight illuminates the scene from the left/upper left.

Design of microstrip patch antennas using knowledge insertion through retraining

NASA Astrophysics Data System (ADS)

Divakar, T. V. S.; Sudhakar, A.

2018-04-01

The traditional way of analyzing/designing neural network is to collect experimental data and train neural network. Then, the trained neural network acts as global approximate function. The network is then used to calculate parameters for unknown configurations. The main drawback of this method is one does not have enough experimental data, cost of prototypes being a major factor [1-4]. Therefore, in this method the author collected training data from available approximate formulas with in full design range and trained the network with it. After successful training, the network is retrained with available measured results. This simple way inserts experimental knowledge into the network [5]. This method is tested for rectangular microstrip antenna and circular microstrip antenna.

Piezoelectric actuator models for active sound and vibration control of cylinders

NASA Technical Reports Server (NTRS)

Lester, Harold C.; Lefebvre, Sylvie

1993-01-01

Analytical models for piezoelectric actuators, adapted from flat plate concepts, are developed for noise and vibration control applications associated with vibrating circular cylinders. The loadings applied to the cylinder by the piezoelectric actuators for the bending and in-plane force models are approximated by line moment and line force distributions, respectively, acting on the perimeter of the actuator patch area. Coupling between the cylinder and interior acoustic cavity is examined by studying the modal spectra, particularly for the low-order cylinder modes that couple efficiently with the cavity at low frequencies. Within the scope of this study, the in-plane force model produced a more favorable distribution of low-order modes, necessary for efficient interior noise control, than did the bending model.

A compact 5.5 GHz band-rejected UWB antenna using complementary split ring resonators.

PubMed

Islam, M M; Faruque, M R I; Islam, M T

2014-01-01

A band-removal property employing microwave frequencies using complementary split ring resonators (CSRRs) is applied to design a compact UWB antenna wishing for the rejection of some frequency band, which is meanwhile exercised by the existing wireless applications. The reported antenna comprises optimization of a circular radiating patch, in which slotted complementary SRRs are implanted. It is printed on low dielectric FR4 substrate material fed by a partial ground plane and a microstrip line. Validated results exhibit that the reported antenna shows a wide bandwidth covering from 3.45 to more than 12 GHz, with a compact dimension of 22 × 26 mm(2), and VSWR < 2, observing band elimination of 5.5 GHz WLAN band.

Compact, Highly Efficient, and Fully Flexible Circularly Polarized Antenna Enabled by Silver Nanowires for Wireless Body-Area Networks.

PubMed

Jiang, Zhi Hao; Cui, Zheng; Yue, Taiwei; Zhu, Yong; Werner, Douglas H

2017-08-01

A compact and flexible circularly polarized (CP) wearable antenna is introduced for wireless body-area network systems at the 2.4 GHz industrial, scientific, and medical (ISM) band, which is implemented by employing a low-loss composite of polydimethylsiloxane (PDMS) and silver nanowires (AgNWs). The circularly polarized radiation is enabled by placing a planar linearly polarized loop monopole above a finite anisotropic artificial ground plane. By truncating the anisotropic artificial ground plane to contain only 2 by 2 unit cells, an integrated antenna with a compact form factor of 0.41λ 0 × 0.41λ 0 × 0.045λ 0 is obtained, all while possessing an improved angular coverage of CP radiation. A flexible prototype was fabricated and characterized, experimentally achieving S 11 <- 15 dB, an axial ratio of less than 3 dB, a gain of around 5.2 dBi, and a wide CP angular coverage in the targeted ISM band. Furthermore, this antenna is compared to a conventional CP patch antenna of the same physical size, which is also comprised of the same PDMS and AgNW composite. The results of this comparison reveal that the proposed antenna has much more stable performance under bending and human body loading, as well as a lower specific absorption rate. In all, the demonstrated wearable antenna offers a compact, flexible, and robust solution which makes it a strong candidate for future integration into body-area networks that require efficient off-body communications.

Predominant mucosal expression of 5-HT4(+h) receptor splice variants in pig stomach and colon

PubMed Central

Priem, Evelien KV; De Maeyer, Joris H; Vandewoestyne, Mado; Deforce, Dieter; Lefebvre, Romain A

2013-01-01

AIM: To investigate cellular 5-HT4(-h/+h) receptor distribution, particularly in the epithelial layer, by laser microdissection and polymerase chain reaction (PCR) in porcine gastrointestinal (GI) tissues. METHODS: A stepwise approach was used to evaluate RNA quality and to study cell-specific 5-HT4 receptor mRNA expression in the porcine gastric fundus and colon descendens. After freezing, staining and laser microdissection and pressure catapulting (LMPC), RNA quality was evaluated by the Experion automated electrophoresis system. 5-HT4 receptor and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expressions were examined by endpoint reverse transcription (RT)-PCR in mucosal and muscle-myenteric plexus (MMP) tissue fractions, in mucosal and MMP parts of hematoxylin and eosin (HE) stained tissue sections and in microdissected patches of the epithelial and circular smooth muscle cell layer in these sections. Pig gastric fundus tissue sections were also stained immunohistochemically (IHC) for enterochromaffin cells (EC cells; MAB352); these cells were isolated by LMPC and examined by endpoint RT-PCR. RESULTS: After HE staining, the epithelial and circular smooth muscle cell layer of pig colon descendens and the epithelial cell layer of gastric fundus were identified morphologically and isolated by LMPC. EC cells of pig gastric fundus were successfully stained by IHC and isolated by LMPC. Freezing, HE and IHC staining, and LMPC had no influence on RNA quality. 5-HT4 receptor and GAPDH mRNA expressions were detected in mucosa and MMP tissue fractions, and in mucosal and MMP parts of HE stained tissue sections of pig colon descendens and gastric fundus. In the mucosa tissue fractions of both GI regions, the expression of h-exon containing receptor [5-HT4(+h) receptor] mRNA was significantly higher (P < 0.01) compared to 5-HT4(-h) receptor expression, and a similar trend was obtained in the mucosal part of HE stained tissue sections. Large microdissected patches of the epithelial and circular smooth muscle cell layer of pig colon descendens and of the epithelial cell layer of pig gastric fundus, also showed 5-HT4 receptor and GAPDH mRNA expression. No 5-HT4 receptor mRNA expression was detected in gastric LMPC-isolated EC cells from IHC stained tissues, which cells were positive for GAPDH. CONCLUSION: Porcine GI mucosa predominantly expresses 5-HT4(+h) receptor splice variants, suggesting their contribution to the 5-HT4 receptor-mediated mucosal effects of 5-HT. PMID:23840113

Fairy circle landscapes under the sea

PubMed Central

Ruiz-Reynés, Daniel; Gomila, Damià; Sintes, Tomàs; Hernández-García, Emilio; Marbà, Núria; Duarte, Carlos M.

2017-01-01

Short-scale interactions yield large-scale vegetation patterns that, in turn, shape ecosystem function across landscapes. Fairy circles, which are circular patches bare of vegetation within otherwise continuous landscapes, are characteristic features of semiarid grasslands. We report the occurrence of submarine fairy circle seascapes in seagrass meadows and propose a simple model that reproduces the diversity of seascapes observed in these ecosystems as emerging from plant interactions within the meadow. These seascapes include two extreme cases, a continuous meadow and a bare landscape, along with intermediate states that range from the occurrence of persistent but isolated fairy circles, or solitons, to seascapes with multiple fairy circles, banded vegetation, and “leopard skin” patterns consisting of bare seascapes dotted with plant patches. The model predicts that these intermediate seascapes extending across kilometers emerge as a consequence of local demographic imbalances along with facilitative and competitive interactions among the plants with a characteristic spatial scale of 20 to 30 m, consistent with known drivers of seagrass performance. The model, which can be extended to clonal growth plants in other landscapes showing fairy rings, reveals that the different seascapes observed hold diagnostic power as to the proximity of seagrass meadows to extinction points that can be used to identify ecosystems at risks. PMID:28782035

Alternative Transfer to the Earth-Moon Lagrangian Points L4 and L5 Using Lunar Gravity assist

NASA Astrophysics Data System (ADS)

Salazar, Francisco; Winter, Othon; Macau, Elbert; Bertachini de Almeida Prado, Antonio Fernando

2012-07-01

Lagrangian points L4 and L5 lie at 60 degrees ahead of and behind Moon in its orbit with respect to the Earth. Each one of them is a third point of an equilateral triangle with the base of the line defined by those two bodies. These Lagrangian points are stable for the Earth-Moon mass ratio. Because of their distance electromagnetic radiations from the Earth arrive on them substantially attenuated. As so, these Lagrangian points represent remarkable positions to host astronomical observatories. However, this same distance characteristic may be a challenge for periodic servicing mission. This paper studies transfer orbits in the planar restricted three-body problem. To avoid solving a two-boundary problem, the patched-conic approximation is used to find initial conditions to transfer a spacecraft between an Earth circular parking orbit and the Lagrangian points L4, L5 (in the Earth-Moon system), such that a swing-by maneuver is applied using the lunar gravity. We also found orbits that can be used to make a tour to the Lagrangian points L4, L5 based on the theorem of image trajectories. Keywords: Stable Lagrangian points, L4, L5, Three-Body problem, Patched Conic, Swing-by

Natural 13C abundance: a tool to trace the incorporation of dung-derived carbon into soil particle-size fractions.

PubMed

Amelung, W; Bol, R; Friedrich, C

1999-01-01

During the decay of 13C enriched dung patches, the; delta 13C signal of surface soil (1-5 cm) increased with a temporary maximum after 42 d. To understand the underlying processes, we investigated the incorporation of dung-derived C into soil particle-size fractions. Dung, collected from beef steers fed on maize (delta 13C = -15.36/1000) or ryegrass (delta 13C = -25.67/1000), was applied in circular patches to a C3 pasture at North Wyke, UK. Triplicates were sampled from surface soil (1-5 cm) at 14, 28, 42, and 70 d after application, pooled, separated into fine (< 0.2 micron) and coarse clay (0.2-2 microns), silt plus fine sand (2-250 microns), and coarse sand (250-2000 microns), and analyzed for total C, N, and delta 13C. As particle-size diameter decreased, the C/N ratios decreased and delta 13C values increased at all plots due to increasing microbial alteration of soil organic matter. After dung application, ca. 60% of dung-derived C in soil was recovered in the 0.2-250 microns fractions during the whole experiment. The proportion of dung-derived C in the fine clay peaked 42 d after dung application, coinciding with the delta 13C maximum in the bulk soil and the maximum leaching rate measured in lysimeters at this time in another study at the same sites. The percentage of dung-derived C as particulate C in the coarse sand fraction increased until the end of the experiment. We conclude that incorporation of C into soil from decomposing dung patches involved both temporary sorption of leached dung C to < 0.2 micron fractions and continuous accumulation of particulate C (> 250 microns).

ARC-1989-AC89-7054

NASA Image and Video Library

1989-08-28

Voyager violet, green and ultraviolet images of Triton were map projected into cylindrical coordinates and combines to produce this false-color terrain map. Several compositionally distinct terrain and geologic features are portrayed. At center is a gray-blue unit referred to as 'cantaloupe' terrain because of its unusual topographic texture. The unit appears to predate other units to the left. Immediately adjacent to the cantaloupe terrain, is a smoother unit, represented by a reddish color, that has been dissected by a prominent fault system. This unit apparently overlies a much-higher-albedo material, seen farther left. A prominent angular albedo boundary separates relatively undisturbed smooth terrain from irregular patches which seem to emanate from circular, often bright-centered features. The parallel streaks may represent vented particulate materials blown in the same direction by winds in Triton's thin atmosphere.

The formation of new quasi-stationary vortex patterns from the interaction of two identical vortices in a rotating fluid

NASA Astrophysics Data System (ADS)

Sokolovskiy, Mikhail A.; Verron, Jacques; Carton, Xavier J.

2018-06-01

Within the framework of the quasi-geostrophic approximation, the interactions of two identical initially circular vortex patches are studied using the contour dynamics/surgery method. The cases of barotropic vortices and of vortices in the upper layer of a two-layer fluid are considered. Diagrams showing the end states of vortex interactions and, in particular, the new regime of vortex triplet formation are constructed for a wide range of external parameters. This paper shows that, in the nonlinear evolution of two such (like-signed) vortices, the filaments and vorticity fragments surrounding the merged vortex often collapse into satellite vortices. Therefore, the conditions for the formation and the quasi-steady motions of a new type of triplet-shaped vortex structure are obtained.

ARC-1989-A89-7030

NASA Image and Video Library

1989-08-25

P-34692 Range : 500 km. ( 300 miles ) Smallest Resolvable Feature : 900 m. or 2,700 ft. Part of Triton's complex geological history canbe seen in this image, shot by Voyager 2. Part of a sequence, it shows a surface dominated by many roughly circular, polygonal, and arcuate features between 30 and 50 km (18 and 30 miles ) across. Some resemble degraded impact craters of Mars, while others resemble the 'palimpsest' features of Jupiter's satellite Ganymede. Peculiar intersecting, double ridged lines are 15 to 20 km. or 9 to 12 miles wide and hundreds of kilometers long. Theyresemble some deformational belts of Ganymede. Patches of plainsforming material tend to occur in local depressions. The geologic features of Triton and spectroscopic information indicates that the surface of Triton is underlain by a mixture of ices.

A Compact 5.5 GHz Band-Rejected UWB Antenna Using Complementary Split Ring Resonators

PubMed Central

Islam, M. M.; Faruque, M. R. I.; Islam, M. T.

2014-01-01

A band-removal property employing microwave frequencies using complementary split ring resonators (CSRRs) is applied to design a compact UWB antenna wishing for the rejection of some frequency band, which is meanwhile exercised by the existing wireless applications. The reported antenna comprises optimization of a circular radiating patch, in which slotted complementary SRRs are implanted. It is printed on low dielectric FR4 substrate material fed by a partial ground plane and a microstrip line. Validated results exhibit that the reported antenna shows a wide bandwidth covering from 3.45 to more than 12 GHz, with a compact dimension of 22 × 26 mm2, and VSWR < 2, observing band elimination of 5.5 GHz WLAN band. PMID:24971379

Design and Experimental Investigation of a Compact Circularly Polarized Integrated Filtering Antenna for Wearable Biotelemetric Devices.

PubMed

Jiang, Zhi Hao; Gregory, Micah D; Werner, Douglas H

2016-04-01

A compact circularly polarized (CP) integrated filtering antenna is reported for wearable biotelemetric devices in the 2.4 GHz ISM band. The design is based on a mutual synthesis of a CP patch antenna connected to a bandpass filter composed of coupled stripline open-loop resonators, which provides an integrated low-profile radiating and filtering module with a compact form factor of 0.44λ(0)×0.44λ(0)×0.04λ(0). The optimized filtering antenna is fabricated and measured, achieving an S11 < -14 dB, an axial ratio of less than 3 dB and gain higher than 3.5 dBi in the targeted ISM band. With the integrated filtering functionality, the antenna exhibits good out-of-band rejection over an ultra-wide frequency range of 1-6 GHz. Further full-wave simulations and experiments were carried out, verifying that the proposed filtering antenna maintains these desirable properties even when mounted in close proximity to the human body at different positions. The stable impedance performance and the simultaneous wide axial ratio and radiated power beam widths make it an ideal candidate as a wearable antenna for off-body communications. The additional integrated filtering functionality further improves utility by greatly reducing interference and crosstalk with other existing wireless systems.

Indoor radio channel modeling and mitigation of fading effects using linear and circular polarized antennas in combination for smart home system at 868 MHz

NASA Astrophysics Data System (ADS)

Wunderlich, S.; Welpot, M.; Gaspard, I.

2014-11-01

The markets for smart home products and services are expected to grow over the next years, driven by the increasing demands of homeowners considering energy monitoring, management, environmental controls and security. Many of these new systems will be installed in existing homes and offices and therefore using radio based systems for cost reduction. A drawback of radio based systems in indoor environments are fading effects which lead to a high variance of the received signal strength and thereby to a difficult predictability of the encountered path loss of the various communication links. For that reason it is necessary to derive a statistical path loss model which can be used to plan a reliable and cost effective radio network. This paper presents the results of a measurement campaign, which was performed in six buildings to deduce realistic radio channel models for a high variety of indoor radio propagation scenarios in the short range devices (SRD) band at 868 MHz. Furthermore, a potential concept to reduce the variance of the received signal strength using a circular polarized (CP) patch antenna in combination with a linear polarized antenna in an one-to-one communication link is presented.

Construction and characterization of mismatch-containing circular DNA molecules competent for assessment of nick-directed human mismatch repair in vitro.

PubMed

Larson, Erik D; Nickens, David; Drummond, James T

2002-02-01

The ability of cell-free extracts to correct DNA mismatches has been demonstrated in both prokaryotes and eukaryotes. Such an assay requires a template containing both a mismatch and a strand discrimination signal, and the multi-step construction process can be technically difficult. We have developed a three-step procedure for preparing DNA heteroduplexes containing a site-specific nick. The mismatch composition, sequence context, distance to the strand signal, and the means for assessing repair in each strand are adjustable features built into a synthetic oligonucleotide. Controlled ligation events involving three of the four DNA strands incorporate the oligonucleotide into a circular template and generate the repair-directing nick. Mismatch correction in either strand of a prototype G.T mismatch was achieved by placing a nick 10-40 bp away from the targeted base. This proximity of nick and mismatch represents a setting where repair has not been well characterized, but the presence of a nick was shown to be essential, as was the MSH2/MSH6 heterodimer, although low levels of repair occurred in extract defective in each protein. All repair events were inhibited by a peptide that interacts with proliferating cell nuclear antigen and inhibits both mismatch repair and long-patch replication.

Modeling and Application of Piezoelectric Materials in Repair of Engineering Structures

NASA Astrophysics Data System (ADS)

Wu, Nan

The shear horizontal wave propagation and vibration of piezoelectric coupled structures under an open circuit electrical boundary condition are studied. Following the studies on the dynamic response of piezoelectric coupled structures, the repair of both crack/notch and delaminated structures using piezoelectric materials are conducted. The main contribution was the proposed the active structural repair design using piezoelectric materials for different structures. An accurate model for the piezoelectric effect on the shear wave propagation is first proposed to guide the application of piezoelectric materials as sensors and actuators in the repair of engineering structures. A vibration analysis of a circular steel substrate surface bonded by a piezoelectric layer with open circuit is presented. The mechanical models and solutions for the wave propagation and vibration analysis of piezoelectric coupled structures are established based on the Kirchhoff plate model and Maxwell equation. Following the studies of the dynamic response of piezoelectric coupled structures, a close-loop feedback control repair methodology is proposed for a vibrating delaminated beam structure by using piezoelectric patches. The electromechanical characteristic of the piezoelectric material is employed to induce a local shear force above the delamination area via an external actuation voltage, which is designed as a feedback of the deflection of a vibrating beam and a delaminated plate, to reduce the stress singularity around the delamination tips. Furthermore, an experimental realization of an effective repair of a notched cantilever beam structure subjected to a dynamic loading by use of piezoelectric patches is reported. A small piezoelectric patch used as a sensor is placed on the notch position to monitor the severity of the stress singularity around the notch area by measuring the charge output on the sensor, and a patch used as an actuator is located around the notch area to generate a required bending moment by employing an actuation voltage to reduce the stress singularity at the notch position. The actuation voltage on the actuator is designed from a feedback circuit process. Through the analytical model, FEM simulation and experimental studies, the active structural repair method using piezoelectric materials is realized and proved to be feasible and practical.

Design of a Class of Antennas Utilizing MEMS, EBG and Septum Polarizers including Near-field Coupling Analysis

NASA Astrophysics Data System (ADS)

Kim, Ilkyu

Recent developments in mobile communications have led to an increased appearance of short-range communications and high data-rate signal transmission. New technologies provides the need for an accurate near-field coupling analysis and novel antenna designs. An ability to effectively estimate the coupling within the near-field region is required to realize short-range communications. Currently, two common techniques that are applicable to the near-field coupling problem are 1) integral form of coupling formula and 2) generalized Friis formula. These formulas are investigated with an emphasis on straightforward calculation and accuracy for various distances between the two antennas. The coupling formulas are computed for a variety of antennas, and several antenna configurations are evaluated through full-wave simulation and indoor measurement in order to validate these techniques. In addition, this research aims to design multi-functional and high performance antennas based on MEMS (Microelectromechanical Systems) switches, EBG (Electromagnetic Bandgap) structures, and septum polarizers. A MEMS switch is incorporated into a slot loaded patch antenna to attain frequency reconfigurability. The resonant frequency of the patch antenna can be shifted using the MEM switch, which is actuated by the integrated bias networks. Furthermore, a high gain base-station antenna utilizing beam-tilting is designed to maximize gain for tilted beam applications. To realize this base-station antenna, an array of four dipole-EBG elements is constructed to implement a fixed down-tilt main beam with application in base station arrays. An improvement of the operating range with the EBG-dipole array is evaluated using a simple linkbudget analysis. The septum polarizer has been widely used in circularly polarized antenna systems due to its simple and compact design and high quality of circularity. In this research, the sigmoid function is used to smoothen the edge in the septum design, which makes it suitable for HPM systems. The PSO (Particle Swarm Optimization) technique is applied to the septum design to achieve a high performance antenna design. The electric field intensity above the septum is evaluated through the simulation and its properties are compared to simple half-plane scattering phenomena.

2-D eddy resolving simulations of flow past a circular array of cylindrical plant stems

NASA Astrophysics Data System (ADS)

Chang, Kyoungsik; Constantinescu, George; Park, Sanghyun

2018-04-01

In the present study, 2-D large eddy simulations (LES) are conducted for flow past a porous circular array with a solid volume fraction (SVF) of 8.8%, 15.4% and 21.5%. Such simulations are relevant to understanding flow in natural streams and channels containing patches of emerged vegetation. In the simulations discussed in the paper, the porous cylinder of diameter D contains a variable number of identical solid circular cylinders (rigid plant stems) of diameter d = 0.048 D. Most of the simulations are conducted at a Reynolds number of 2 100 based on the diameter D and the velocity of the steady uniform incoming flow. Though in all cases wake billows are shed in the regions where the separated shear layers (SSLs) forming on the sides of the porous cylinder interact, the effect of these wake billows on the mean drag is different. While in the high SVF case (21.5%), the total drag force oscillates quasi-regularly in time, similar to the canonical case of a large solid cylinder, in the cases with a lower SVF the shedding of the wake billows takes place sufficiently far from the cylinder such that the unsteady component of the total drag force is negligible. The mean amplitude of the oscillations of the drag force on the individual cylinders is the largest in a streamwise band centered around the center of the porous cylinder, where the wake to wake interactions are the strongest. In all cases the maximum drag force on the individual cylinders is the largest for the cylinders directly exposed to the flow, but this force is always smaller than the one induced on a small isolated cylinder and the average magnitude of the force on the cylinders directly exposed to the flow decreases monotonically with the increase in the SVF. Predictions of the global drag coefficients, Strouhal numbers associated with the wake vortex shedding and individual forces on the cylinders in the array from the present LES are in very good agreement with those of 2-D direct numerical simulations conducted on finer meshes, which suggests LES is a better option to numerically investigate flow in channels containing canopy patches, given that LES is computationally much less expensive than DNS at high Reynolds number. To prove this point, the paper also discusses results of 2-D LES conducted at a much higher Reynolds number, where the near-wake flow is strongly turbulent. For the higher Reynolds number cases, where the influence of the turbulence model is important, the effect of the sub-grid scale model and the predictive capabilities of the unsteady Reynolds averaged Navier-Stokes (RANS) approach to predict flow past porous cylinders are discussed.

Preservation of viral genomes in 700-y-old caribou feces from a subarctic ice patch

PubMed Central

Chen, Li-Fang; Zhou, Yanchen; Shapiro, Beth; Stiller, Mathias; Varsani, Arvind; Kondov, Nikola O.; Wong, Walt; Deng, Xutao; Andrews, Thomas D.; Moorman, Brian J.; Meulendyk, Thomas; MacKay, Glen; Gilbertson, Robert L.; Delwart, Eric

2014-01-01

Viruses preserved in ancient materials provide snapshots of past viral diversity and a means to trace viral evolution through time. Here, we use a metagenomics approach to identify filterable and nuclease-resistant nucleic acids preserved in 700-y-old caribou feces frozen in a permanent ice patch. We were able to recover and characterize two viruses in replicated experiments performed in two different laboratories: a small circular DNA viral genome (ancient caribou feces associated virus, or aCFV) and a partial RNA viral genome (Ancient Northwest Territories cripavirus, or aNCV). Phylogenetic analysis identifies aCFV as distantly related to the plant-infecting geminiviruses and the fungi-infecting Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 and aNCV as within the insect-infecting Cripavirus genus. We hypothesize that these viruses originate from plant material ingested by caribou or from flying insects and that their preservation can be attributed to protection within viral capsids maintained at cold temperatures. To investigate the tropism of aCFV, we used the geminiviral reverse genetic system and introduced a multimeric clone into the laboratory model plant Nicotiana benthamiana. Evidence for infectivity came from the detection of viral DNA in newly emerged leaves and the precise excision of the viral genome from the multimeric clones in inoculated leaves. Our findings indicate that viral genomes may in some circumstances be protected from degradation for centuries. PMID:25349412

The lakes of Titan

USGS Publications Warehouse

Stofan, E.R.; Elachi, C.; Lunine, J.I.; Lorenz, R.D.; Stiles, B.; Mitchell, K.L.; Ostro, S.; Soderblom, L.; Wood, C.; Zebker, H.; Wall, S.; Janssen, M.; Kirk, R.; Lopes, R.; Paganelli, F.; Radebaugh, J.; Wye, L.; Anderson, Y.; Allison, M.; Boehmer, R.; Callahan, P.; Encrenaz, P.; Flamini, E.; Francescetti, G.; Gim, Y.; Hamilton, G.; Hensley, S.; Johnson, W.T.K.; Kelleher, K.; Muhleman, D.; Paillou, P.; Picardi, G.; Posa, F.; Roth, L.; Seu, R.; Shaffer, S.; Vetrella, S.; West, R.

2007-01-01

The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar flyby of Titan on 22 July 2006 (T16). The radar imaging polewards of 70?? north shows more than 75 circular to irregular radar-dark patches, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. The radar-dark patches are interpreted as lakes on the basis of their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. Some of the lakes do not completely fill the depressions in which they lie, and apparently dry depressions are present. We interpret this to indicate that lakes are present in a number of states, including partly dry and liquid-filled. These northern-hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface 'liquid methane' table. ??2007 Nature Publishing Group.

A Millimeter-Wave Cavity-Backed Suspended Substrate Stripline Antenna

NASA Technical Reports Server (NTRS)

Simons, Rainee N.

1999-01-01

Future generation satellite communication systems in near-Earth orbit will operate at frequencies in the higher mm-wave frequency bands. These satellite systems require low-profile, high gain, light weight and low cost antennas for communications to and from Earth as well as for inter-satellite links (ISL). At higher mm-wave frequencies, the conductor loss of conventional microstrip line is high and consequently the feed network loss of patch antenna arrays is also high. The high loss lowers the array efficiency, and in addition lowers the G/T ratio in a receiving array. Recently a radial line slot antenna array has been demonstrated to have high gain and efficiency at 60 GHz. In this paper, the design, fabrication and characterization of a V-Band (50-75 GHz), cavity backed, circular aperture antenna with suspended substrate stripline (SSS) feed is presented.

A software module for implementing auditory and visual feedback on a video-based eye tracking system

NASA Astrophysics Data System (ADS)

Rosanlall, Bharat; Gertner, Izidor; Geri, George A.; Arrington, Karl F.

2016-05-01

We describe here the design and implementation of a software module that provides both auditory and visual feedback of the eye position measured by a commercially available eye tracking system. The present audio-visual feedback module (AVFM) serves as an extension to the Arrington Research ViewPoint EyeTracker, but it can be easily modified for use with other similar systems. Two modes of audio feedback and one mode of visual feedback are provided in reference to a circular area-of-interest (AOI). Auditory feedback can be either a click tone emitted when the user's gaze point enters or leaves the AOI, or a sinusoidal waveform with frequency inversely proportional to the distance from the gaze point to the center of the AOI. Visual feedback is in the form of a small circular light patch that is presented whenever the gaze-point is within the AOI. The AVFM processes data that are sent to a dynamic-link library by the EyeTracker. The AVFM's multithreaded implementation also allows real-time data collection (1 kHz sampling rate) and graphics processing that allow display of the current/past gaze-points as well as the AOI. The feedback provided by the AVFM described here has applications in military target acquisition and personnel training, as well as in visual experimentation, clinical research, marketing research, and sports training.

Alternative transfer to the Earth-Moon Lagrangian points L4 and L5 using lunar gravity assist

NASA Astrophysics Data System (ADS)

Salazar, F. J. T.; Macau, E. E. N.; Winter, O. C.

2014-02-01

Lagrangian points L4 and L5 lie at 60° ahead of and behind the Moon in its orbit with respect to the Earth. Each one of them is a third point of an equilateral triangle with the base of the line defined by those two bodies. These Lagrangian points are stable for the Earth-Moon mass ratio. As so, these Lagrangian points represent remarkable positions to host astronomical observatories or space stations. However, this same distance characteristic may be a challenge for periodic servicing mission. This paper studies elliptic trajectories from an Earth circular parking orbit to reach the Moon's sphere of influence and apply a swing-by maneuver in order to re-direct the path of a spacecraft to a vicinity of the Lagrangian points L4 and L5. Once the geocentric transfer orbit and the initial impulsive thrust have been determined, the goal is to establish the angle at which the geocentric trajectory crosses the lunar sphere of influence in such a way that when the spacecraft leaves the Moon's gravitational field, its trajectory and velocity with respect to the Earth change in order to the spacecraft arrives at L4 and L5. In this work, the planar Circular Restricted Three Body Problem approximation is used and in order to avoid solving a two boundary problem, the patched-conic approximation is considered.

Resonant Formation and Control of m-Fold Symmetric V-States

NASA Astrophysics Data System (ADS)

Friedland, Lazar; Shagalov, Arkadi

2000-10-01

Magnetized, pure electron plasmas trapped in a Malmberg-Penning trap can be modeled (in the drift approximation) by two-dimensional Euler equations of ideal fluids. The plasma density in this approximation is analogous to vorticity, while the radial electric field potential to the stream function of the fluid velocity field. For instance, electron plasma cylinder aligned with the magnetic field is analogous to a circular vortex patch solution of an ideal fluid. We shall show that by starting in such a circular equilibrium one can drive an m-fold symmetric interface (vortex) waves in two dimensions (V-states, discovered by Deem and Zabusky [1] nearly 20 years ago)into a highly nonlinear excitation by applying a weak external oscillating potential of appropriate symmetry and slowly varying the frequency of these oscillations. The phenomenon is due to autoresonance [2,3] in the system as the excited plasma (vortex) boundary preserves its functional form despite the drive, but self-adjusts the aspect ratio to synchronize with the driving potential oscillations. A similar approach can be used in controlling interface dynamics subject to global constraints in many other fields of physics. Work supported by Israel Science Foundation grant 607-97 and INTAS grant 99-1068. [1] G. Deem and N. Zabusky, Phys. Rev. Lett. 40, 859 (1978). [2] L. Friedland, Phys. Rev. E, 4106 (1999). [3] J. Fajans, E. Gilson, and L. Friedland, Phys. Rev. Lett. 82, 4444 (1999).

Physiology and growth of advance Picea rubens and Abies balsamea regeneration following different canopy openings.

PubMed

Dumais, Daniel; Prévost, Marcel

2014-02-01

We examined the ecophysiology and growth of 0.3-1.3 m tall advance red spruce (Picea rubens Sarg.) and balsam fir (Abies balsamea [L.] Mill.) regeneration during a 5-year period following the application of different harvest types producing three sizes of canopy openings: (i) small gaps (<100 m(2) in area; SMA) created by partial uniform single-tree harvest; (ii) irregular gaps of intermediate size (100-300 m(2); INT) created by group-selection harvest (removal of groups of trees, mainly balsam fir, with uniform partial removal between groups); and (iii) large circular gaps (700 m(2); LAR) created by patch-selection harvest (removal of trees in 30-m diameter circular areas with uniform partial removal between gaps). An unharvested control (CON) was monitored for comparison. At the ecophysiological level, we mainly found differences in light-saturated photosynthesis of red spruce and specific leaf area of balsam fir among treatments. Consequently, we observed good height growth of both species in CON and INT, but fir surpassed spruce in SMA and LAR. Results suggest that intermediate 100-300 m(2) irregular openings create microenvironmental conditions that may promote short-term ecophysiology and growth of red spruce, allowing the species to compete with balsam fir advance regeneration. Finally, results observed for spruce in large 700-m(2) openings confirm its inability to grow as rapidly as fir in comparable open conditions.

The Differences in Source Dynamics Between Intermediate-Depth and Deep EARTHQUAKES:A Comparative Study Between the 2014 Rat Islands Intermediate-Depth Earthquake and the 2015 Bonin Islands Deep Earthquake

NASA Astrophysics Data System (ADS)

Twardzik, C.; Ji, C.

2015-12-01

It has been proposed that the mechanisms for intermediate-depth and deep earthquakes might be different. While previous extensive seismological studies suggested that such potential differences do not significantly affect the scaling relationships of earthquake parameters, there has been only a few investigations regarding their dynamic characteristics, especially for fracture energy. In this work, the 2014 Mw7.9 Rat Islands intermediate-depth (105 km) earthquake and the 2015 Mw7.8 Bonin Islands deep (680 km) earthquake are studied from two different perspectives. First, their kinematic rupture models are constrained using teleseismic body waves. Our analysis reveals that the Rat Islands earthquake breaks the entire cold core of the subducting slab defined as the depth of the 650oC isotherm. The inverted stress drop is 4 MPa, compatible to that of intra-plate earthquakes at shallow depths. On the other hand, the kinematic rupture model of the Bonin Islands earthquake, which occurred in a region lacking of seismicity for the past forty years, according to the GCMT catalog, exhibits an energetic rupture within a 35 km by 30 km slip patch and a high stress drop of 24 MPa. It is of interest to note that although complex rupture patterns are allowed to match the observations, the inverted slip distributions of these two earthquakes are simple enough to be approximated as the summation of a few circular/elliptical slip patches. Thus, we investigate subsequently their dynamic rupture models. We use a simple modelling approach in which we assume that the dynamic rupture propagation obeys a slip-weakening friction law, and we describe the distribution of stress and friction on the fault as a set of elliptical patches. We will constrain the three dynamic parameters that are yield stress, background stress prior to the rupture and slip weakening distance, as well as the shape of the elliptical patches directly from teleseismic body waves observations. The study would help us getting a better understanding of the dynamic conditions that control the rupture behaviour of these two types of earthquakes, and subsequently improving our knowledge of the dynamics of subducting slabs.

Landscape heterogeneity reduces coyote predation on white-tailed deer fawns

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

Gulsby, William D.; Kilgo, John C.; Vukovich, Mark

Coyote (Canis latrans) predation on white-tailed deer (Odocoileus virginianus) fawns in southeastern North America has led to deer population declines in some areas. Research or management efforts initiated in response to coyote predation on fawns have primarily focused on implementation of reduced antlerless deer harvest or coyote control to mitigate population declines. Vegetation characteristics may influence coyote hunting efficiency, but the potential influence of land cover at large scales in the southeastern United States is underexplored. We investigated whether mortality risk was affected by landscape characteristics within fawn home ranges for a sample of 165 fawns on the United Statesmore » Department of Energy’s Savannah River Site (SRS), South Carolina, 2007–2012. We monitored fawns every 8 hours to ≥ 4 weeks of age and 1–3 times daily to 12 weeks of age. We included only surviving or coyote-predated fawns in the dataset. The most supported model describing hazard ratios included the length of edge (i.e., area where 2 land cover types joined) in fawn home ranges. Probability of coyote predation increased 1.26 times for each 968-m decrease in edge within a fawn’s simulated home range (29.1-ha circular buffer) under this model. Further, fawns with the least edge in their home ranges were >2 times more likely to be depredated by a coyote than fawns with the greatest edge availability. Support for other models was relatively low, but informative variables (e.g., mean patch fractal dimension, Shannon’s diversity index, mean forest patch size) supported a general trend that as fawn home ranges became more homogeneous and contained larger patches with less edge and fewer cover types, predation risk increased. These findings are consistent with similar work in the midwestern United States, despite landscape differences between regions. The combined weight of evidence suggests maintenance of a heterogeneous landscape consisting of relatively small dispersed patches may reduce fawn losses to coyotes. In conclusion, this information may also be used to identify areas susceptible to greater fawn predation rates across large spatial scales. However, the relatively long forestry rotation lengths and large scale of consistent forest management on the SRS are uncommon in the southeastern United States and the mechanism for the pattern we observed is unclear. Therefore, our results may not be applicable to sites with different forest management practices.« less

Landscape heterogeneity reduces coyote predation on white-tailed deer fawns

DOE PAGES

Gulsby, William D.; Kilgo, John C.; Vukovich, Mark; ...

2017-03-07

Coyote (Canis latrans) predation on white-tailed deer (Odocoileus virginianus) fawns in southeastern North America has led to deer population declines in some areas. Research or management efforts initiated in response to coyote predation on fawns have primarily focused on implementation of reduced antlerless deer harvest or coyote control to mitigate population declines. Vegetation characteristics may influence coyote hunting efficiency, but the potential influence of land cover at large scales in the southeastern United States is underexplored. We investigated whether mortality risk was affected by landscape characteristics within fawn home ranges for a sample of 165 fawns on the United Statesmore » Department of Energy’s Savannah River Site (SRS), South Carolina, 2007–2012. We monitored fawns every 8 hours to ≥ 4 weeks of age and 1–3 times daily to 12 weeks of age. We included only surviving or coyote-predated fawns in the dataset. The most supported model describing hazard ratios included the length of edge (i.e., area where 2 land cover types joined) in fawn home ranges. Probability of coyote predation increased 1.26 times for each 968-m decrease in edge within a fawn’s simulated home range (29.1-ha circular buffer) under this model. Further, fawns with the least edge in their home ranges were >2 times more likely to be depredated by a coyote than fawns with the greatest edge availability. Support for other models was relatively low, but informative variables (e.g., mean patch fractal dimension, Shannon’s diversity index, mean forest patch size) supported a general trend that as fawn home ranges became more homogeneous and contained larger patches with less edge and fewer cover types, predation risk increased. These findings are consistent with similar work in the midwestern United States, despite landscape differences between regions. The combined weight of evidence suggests maintenance of a heterogeneous landscape consisting of relatively small dispersed patches may reduce fawn losses to coyotes. In conclusion, this information may also be used to identify areas susceptible to greater fawn predation rates across large spatial scales. However, the relatively long forestry rotation lengths and large scale of consistent forest management on the SRS are uncommon in the southeastern United States and the mechanism for the pattern we observed is unclear. Therefore, our results may not be applicable to sites with different forest management practices.« less

[Health statistics aren't born in a cabbage patch: Jesuits, political arithmetic, stigmergy and oligopticons].

PubMed

Carvajal, Yuri; Yuing, Tuillang

2013-04-01

By analyzing the content and network of production of a map from 1751, created by the circular mission of the Jesuits in Chiloé (an archipelago located off the southern coast of Chile), that contains birth, death and population data, this article discusses the role that health statistics play historically, philosophically, technically and sociologically. In doing so, the article seeks to comprehend the genesis of a process of production of data and references in order to debate what health statistics are composed of, what ends they are used for, what their connection is to the formation of collectives and the differential conditions of possibility that exist for producing statistics. We attempt to develop hypotheses that demonstrate statistics as a hybrid articulation between diverse elements, epistemological, biopolitical, historical and philosophical in nature, with facets at once religious and demographic, ontological and ethnic, scientific and governmental.

A Millimeter-wave Cavity-backed Suspended Substrate Stripline Antenna

NASA Technical Reports Server (NTRS)

Simons, Rainee N.

1999-01-01

Future generation satellite communication systems in near-Earth orbit will operate at frequencies in the higher mm-wave frequency hands. These satellite systems require low-profile, high gain, light weight and low cost antennas for communications to and from Earth as well as for inter-satellite links (ISL). At higher mm-wave frequencies, the conductor loss of conventional microstrip line is high and consequently the feed network loss of patch antenna arrays is also high. The high loss lowers the array efficiency and in addition lowers the G/T ratio in a receiving array. Recently a radial line slot antenna array has been demonstrated to have high gain and efficiency at 60 GHz. In this paper, the design, fabrication and characterization of a V-Band (50-75 GHz) 4 x 4 planar array of cavity backed circular aperture antennas with suspended substrate stripline (SSS) corporate feed is presented.

Reconfigurable phased antenna array for extending cubesat operations to Ka-band: Design and feasibility

NASA Astrophysics Data System (ADS)

Buttazzoni, G.; Comisso, M.; Cuttin, A.; Fragiacomo, M.; Vescovo, R.; Vincenti Gatti, R.

2017-08-01

Started as educational tools, CubeSats have immediately encountered the favor of the scientific community, subsequently becoming viable platforms for research and commercial applications. To ensure competitive data rates, some pioneers have started to explore the usage of the Ka-band beside the conventional amateur radio frequencies. In this context, this study proposes a phased antenna array design for Ka-band downlink operations consisting of 8×8 circularly polarized subarrays of microstrip patches filling one face of a single CubeSat unit. The conceived structure is developed to support 1.5 GHz bandwidth and dual-task missions, whose feasibility is verified by proper link budgets. The dual-task operations are enabled by a low-complexity phase-only control algorithm that provides pattern reconfigurability in order to satisfy both orbiting and intersatellite missions, while remaining adherent to the cost-effective CubeSat paradigm.

A Double-Negative Metamaterial-Inspired Mobile Wireless Antenna for Electromagnetic Absorption Reduction.

PubMed

Alam, Touhidul; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2015-07-29

A double-negative metamaterial-inspired antenna is presented for mobile wireless applications. The antenna consists of a semi-circular radiating patch and a 3 × 4 hexagonal shaped metamaterial unit cell array in the ground plane. The antenna is fed with a 50 Ω microstrip feed line. The electric dimensions of the proposed antenna are 0.20λ × 0.26λ × 0.004λ, at the low-end frequency. The proposed antenna achieves a -10 dB impedance with a bandwidth of 2.29 GHz at the lower band and 1.28 GHz at the upper band and can operate for most of the mobile applications such as upper GSM bands, WiMAX, Bluetooth, and wireless local area network (WLAN) frequency bands. The focused novelties of the proposed antenna are its small size, multi-standard operating bands, and electromagnetic absorption reduction at all the operating frequencies using the double-negative metamaterial ground plane.

APPROACH & LANDING TEST (ALT) - SHUTTLE PATCH

NASA Image and Video Library

1976-11-01

S76-30340 (1976) --- This circular, red, white and blue emblem has been chosen as the official insignia for the Space Shuttle Approach and Landing Test (ALT) flights. A picture of the Orbiter 101 "Enterprise" is superimposed over a red triangle, which in turn is superimposed over a large inner circle of dark blue. The surnames of the members of the two ALT crews are in white in the field of blue. The four crew men are astronauts Fred W. Haise Jr., commander of the first crew; Joe H. Engle, commander of the second crew; and Richard H. Truly, pilot of the second crew. ALT is a series of flights with a modified Boeing 747 Shuttle Carrier Aircraft (SCA) as a ferry aircraft and airborne launch platform for the 67,300 kilogram (75-ton) "Enterprise". The Shuttle Orbiter atmospheric testing is in preparation for the first Earth-orbital flights scheduled in 1979.

A Combined FEM/MoM/GTD Technique To Analyze Elliptically Polarized Cavity-Backed Antennas With Finite Ground Plane

NASA Technical Reports Server (NTRS)

Reddy, C. J.; Deshpande, M. D.; Fralick, D. T.; Cockrell, C. R.; Beck, F. B.

1996-01-01

Radiation pattern prediction analysis of elliptically polarized cavity-backed aperture antennas in a finite ground plane is performed using a combined Finite Element Method/Method of Moments/Geometrical Theory of Diffraction (FEM/MoM/GTD) technique. The magnetic current on the cavity-backed aperture in an infinite ground plane is calculated using the combined FEM/MoM analysis. GTD, including the slope diffraction contribution, is used to calculate the diffracted fields caused by both soft and hard polarizations at the edges of the finite ground plane. Explicit expressions for regular diffraction coefficients and slope diffraction coefficients are presented. The slope of the incident magnetic field at the diffraction points is derived and analytical expressions are presented. Numerical results for the radiation patterns of a cavity-backed circular spiral microstrip patch antenna excited by a coaxial probe in a finite rectangular ground plane are computed and compared with experimental results.

Simulating the Evolving Behavior of Secondary Slow Slip Fronts

NASA Astrophysics Data System (ADS)

Peng, Y.; Rubin, A. M.

2017-12-01

High-resolution tremor catalogs of slow slip events reveal secondary slow slip fronts behind the main front that repetitively occupy the same source area during a single episode. These repetitive fronts are most often observed in regions with high tremor density. Their recurrence intervals gradually increase from being too short to be tidally modulated (tens of minutes) to being close to tidal periods (about 12 or 24 hours). This could be explained by a decreasing loading rate from creep in the surrounding regions (with few or no observable tremor events) as the main front passes by. As the recurrence intervals of the fronts increase, eventually they lock in on the tidal periods. We attempt to simulate this numerically using a rate-and-state friction law that transitions from velocity-weakening at low slip speeds to velocity strengthening at high slip speeds. Many small circular patches with a cutoff velocity an order of magnitude higher than that of the background are randomly placed on the fault, in order to simulate the average properties of the high-density tremor zone. Preliminary results show that given reasonable parameters, this model produces similar propagation speeds of the forward-migrating main front inside and outside the high-density tremor zone, consistent with observations. We will explore the behavior of the secondary fronts that arise in this model, in relation to the local density of the small tremor-analog patches, the overall geometry of the tremor zone and the tides.

Photolithographic-stereolithographic-tandem fabrication of 4D smart scaffolds for improved stem cell cardiomyogenic differentiation.

PubMed

Miao, Shida; Cui, Haitao; Nowicki, Margaret; Lee, Se-Jun; Almeida, José; Zhou, Xuan; Zhu, Wei; Yao, Xiaoliang; Masood, Fahed; Plesniak, Michael W; Mohiuddin, Muhammad; Zhang, Lijie Grace

2018-05-02

4D printing is a highly innovative additive manufacturing process for fabricating smart structures with the ability to transform over time. Significantly different from regular 4D printing techniques, this study focuses on creating novel 4D hierarchical micropatterns using a unique photolithographic-stereolithographic-tandem strategy (PSTS) with smart soybean oil epoxidized acrylate (SOEA) inks for effectively regulating human bone marrow mesenchymal stem cell (hMSC) cardiomyogenic behaviors. The 4D effect refers to autonomous conversion of the surficial-patterned scaffold into a predesigned construct through an external stimulus delivered immediately after printing. Our results show that hMSCs actively grew and were highly aligned along the micropatterns, forming an uninterrupted cellular sheet. The generation of complex patterns was evident by triangular and circular outlines appearing in the scaffolds. This simple, yet efficient, technique was validated by rapid printing of scaffolds with well-defined and consistent micro-surface features. A 4D dynamic shape change transforming a 2-D design into flower-like structures was observed. The printed scaffolds possessed a shape memory effect beyond the 4D features. The advanced 4D dynamic feature may provide seamless integration with damaged tissues or organs, and a proof of concept 4D patch for cardiac regeneration was demonstrated for the first time. The 4D-fabricated cardiac patch showed significant cardiomyogenesis confirmed by immunofluorescence staining and qRT-PCR analysis, indicating its promising potential in future tissue and organ regeneration applications.

Lateral Downflows in Sunspot Penumbral Filaments and their Temporal Evolution

NASA Astrophysics Data System (ADS)

Esteban Pozuelo, S.; Bellot Rubio, L. R.; de la Cruz Rodríguez, J.

2015-04-01

We study the temporal evolution of downflows observed at the lateral edges of penumbral filaments in a sunspot located very close to the disk center. Our analysis is based on a sequence of nearly diffraction-limited scans of the Fe i 617.3 nm line taken with the CRisp Imaging Spectro-Polarimeter instrument at the Swedish 1 m Solar Telescope. We compute Dopplergrams from the observed intensity profiles using line bisectors and filter the resulting velocity maps for subsonic oscillations. Lateral downflows appear everywhere in the center-side penumbra as small, weak patches of redshifts next to or along the edges of blueshifted flow channels. These patches have an intermittent life and undergo mergings and fragmentations quite frequently. The lateral downflows move together with the hosting filaments and react to their shape variations, very much resembling the evolution of granular convection in the quiet Sun. There is a good relation between brightness and velocity in the center-side penumbra, with downflows being darker than upflows on average, which is again reminiscent of quiet Sun convection. These results point to the existence of overturning convection in sunspot penumbrae, with elongated cells forming filaments where the flow is upward but very inclined, and weak lateral downward flows. In general, the circular polarization profiles emerging from the lateral downflows do not show sign reversals, although sometimes we detect three-lobed profiles that are suggestive of opposite magnetic polarities in the pixel.

Mount Etna, Sicily taken from Atlantis during STS-106

NASA Image and Video Library

2000-10-04

STS106-706-055 (8-20 September 2000) --- One of the STS-106 crew members on board the Space Shuttle Atlantis used a handheld 70mm camera to photograph this image of the Etna Volcano on Sicily. Mt. Etna is known as the volcano with the longest record of volcanic activity with the first being in 1500 BC. It has erupted many times since then and is almost continuously venting gas and steam, as shown in this view. Astronauts can almost be assured of seeing some venting whenever they fly in orbit. Mt. Etna appears as a cone with an almost circular base in this near-vertical view. The Salso River winds around the western and southern flanks of the volcano. The city of Catania appears as a diffuse gray patch at the foot of the volcano where the river meets the Mediterranean Sea. Mt. Etna has a complex of cones at its summit, which is nearly 3300 meters above sea level. Its slopes are a patchwork of colors, the darker colors being lava flows of different ages. Greens are patches of forest on slopes which have not been disrupted by lava and ash in the last few decades. Mt. Etna is a constructional landform which has been built upwards for millennia; it contrasts subtly but distinctly in this view with the surrounding lower hills which are water-eroded landforms everywhere sculpted into V-shaped valleys by the erosive power of flowing water of streams.

Fabrication of anti-vitiligo ointment containing Psoralea corylifolia: in vitro and in vivo characterization.

PubMed

Hussain, Irshad; Hussain, Nisar; Manan, Abdul; Rashid, Abdur; Khan, Barkat; Bakhsh, Sattar

2016-01-01

Vitiligo is a repugnant and odious dermatological malady of the time. It has an detrimental impact on the pigmentation of the human skin as a result of the destruction of cutaneous melanocytes. It affects 1%-2% of the population worldwide. Different therapeutic regimens have been deployed to treat vitiligo, but none of them could stand alone to be stated as a perfect cure. Recently, a change has been observed through novel experimental-designed optimization leading to the development of an anti-vitiligo ointment containing Psoralea corylifolia (PC) seed powder. The aim of this study was to explore the clinical outcomes of ointment containing powdered seeds of PC. Guided by the protocol Response Surface Methodology, 13 formulations of concentration variance of permeation enhancers were prepared. The formulation fulfilling the required criteria (pH; temperature stability tests at 8°C±0.1°C, 25°C±0.1°C and 40°C±0.1°C; and the physical properties such as color, bleeding and rheology) was selected for clinical trials. Fourier transform infrared spectroscopy studies of seed powder of PC and selected formulation of the seed powder were performed. After obtaining informed consents and with prior approval of university and hospital ethical review boards, 20 patients (age range 25-65 years) were included in the present study. Formulations were applied on the affected body parts of patients, and some affected portion of the same patient was taken as control (self-control study design). The pigmentation of white spots of vitiligo was photographically evaluated before, during and after 12 weeks of treatment. Analysis of the measured values was performed using GraphPad Prism version 5 statistical software. A paired sample t -test was performed to observe variation between repigmented patches and white patches of self-control. Hydrophilic ointment (10% w/w) prepared with seed powder of PC was fabricated. The ointment was found effective for small circular white lesions of vitiligo as compared to self-control. Pre- and post-treatment differences in the levels of pigmentation were statistically significant ( P ≤0.05). Ointment containing seed powder of PC could be an effective monotherapy for small circular white lesions of vitiligo.

Circular stapled pyloroplasty: a fast and effective technique for pyloric disruption during esophagectomy with gastric pull-up.

PubMed

Oezcelik, A; DeMeester, S R; Hindoyan, K; Leers, J M; Ayazi, S; Abate, E; Zehetner, J; Hagen, J A; Lipham, J C; DeMeester, T R

2011-08-01

The necessity of pyloroplasty after esophagectomy and gastric pull-up is debated. Disadvantages of a standard pyloroplasty include the potential for leak, shortening of the length of the graft, and complexity when done during a minimally invasive procedure. The aim of this study is to report our experience with a novel internal pyloroplasty technique using a circular stapler (CS pyloroplasty), which is applicable for both laparoscopic and open esophagectomy. The records of all patients who underwent an esophagectomy with gastric pull-up and pyloroplasty between 2002 and 2007 were reviewed. The CS pyloroplasty was performed through a lesser curve gastrotomy with a 21-mm CS, while the standard pyloroplasty entailed a longitudinal full thickness incision through the pylorus with mucosal closure in the same direction and a Graham patch. A CS pyloroplasty was performed in 144 and a standard pyloroplasty in 133 patients. The median patient age was 66years, and the median follow-up was 17months, and was similar for both types of pyloroplasty. Routine postoperative videoesophagram was significantly more likely to show a delay in contrast transit through the pylorus after standard pyloroplasty (16% standard vs. 8% CS pyloroplasty, P= 0.03). Significantly more patients had postoperative endoscopy after standard pyloroplasty (40% standard vs. 24% CS pyloroplasty, P= 0.004), but the frequency of pyloric dilatation was similar. There were no leaks with either technique. A circular stapled pyloroplasty is as efficacious as a standard pyloroplasty after esophagectomy with gastric pull-up. Potential advantages include the ease and simplicity of the procedure along with virtually no risk of a leak and no graft shortening. The technique is amenable to both open and minimally invasive procedures. © 2011 Copyright the Authors. Journal compilation © 2011, Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

Oracle Applications Patch Administration Tool (PAT) Beta Version

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

2002-01-04

PAT is a Patch Administration Tool that provides analysis, tracking, and management of Oracle Application patches. This includes capabilities as outlined below: Patch Analysis & Management Tool Outline of capabilities: Administration Patch Data Maintenance -- track Oracle Application patches applied to what database instance & machine Patch Analysis capture text files (readme.txt and driver files) form comparison detail report comparison detail PL/SQL package comparison detail SQL scripts detail JSP module comparison detail Parse and load the current applptch.txt (10.7) or load patch data from Oracle Application database patch tables (11i) Display Analysis -- Compare patch to be applied with currentmore » Oracle Application installed Appl_top code versions Patch Detail Module comparison detail Analyze and display one Oracle Application module patch. Patch Management -- automatic queue and execution of patches Administration Parameter maintenance -- setting for directory structure of Oracle Application appl_top Validation data maintenance -- machine names and instances to patch Operation Patch Data Maintenance Schedule a patch (queue for later execution) Run a patch (queue for immediate execution) Review the patch logs Patch Management Reports« less

Maintaining social cohesion is a more important determinant of patch residence time than maximizing food intake rate in a group-living primate, Japanese macaque (Macaca fuscata).

PubMed

Kazahari, Nobuko

2014-04-01

Animals have been assumed to employ an optimal foraging strategy (e.g., rate-maximizing strategy). In patchy food environments, intake rate within patches is positively correlated with patch quality, and declines as patches are depleted through consumption. This causes patch-leaving and determines patch residence time. In group-foraging situations, patch residence times are also affected by patch sharing. Optimal patch models for groups predict that patch residence times decrease as the number of co-feeding animals increases because of accelerated patch depletion. However, group members often depart patches without patch depletion, and their patch residence time deviates from patch models. It has been pointed out that patch residence time is also influenced by maintaining social proximity with others among group-living animals. In this study, the effects of maintaining social cohesion and that of rate-maximizing strategy on patch residence time were examined in Japanese macaques (Macaca fuscata). I hypothesized that foragers give up patches to remain in the proximity of their troop members. On the other hand, foragers may stay for a relatively long period when they do not have to abandon patches to follow the troop. In this study, intake rate and foraging effort (i.e., movement) did not change during patch residency. Macaques maintained their intake rate with only a little foraging effort. Therefore, the patches were assumed to be undepleted during patch residency. Further, patch residence time was affected by patch-leaving to maintain social proximity, but not by the intake rate. Macaques tended to stay in patches for short periods when they needed to give up patches for social proximity, and remained for long periods when they did not need to leave to keep social proximity. Patch-leaving and patch residence time that prioritize the maintenance of social cohesion may be a behavioral pattern in group-living primates.

An ecological mechanism to create regular patterns of surface dissolution in a low-relief carbonate landscape

NASA Astrophysics Data System (ADS)

Cohen, M. J.; Martin, J. B.; Mclaughlin, D. L.; Osborne, T.; Murray, A.; Watts, A. C.; Watts, D.; Heffernan, J. B.

2012-12-01

Development of karst landscapes is controlled by focused delivery of water undersaturated with respect to the soluble rock minerals. As that water comes to equilibrium with the rock, secondary porosity is incrementally reinforced creating a positive feedback that acts to augment the drainage network and subsequent water delivery. In most self-organizing systems, spatial positive feedbacks create features (in landscapes: patches; in karst aquifers: conduits) whose size-frequency relationship follows a power function, indicating a higher probability of large features than would occur with a random or Gaussian genesis process. Power functions describe several aspects of secondary porosity in the Upper Floridan Aquifer in north Florida. In contrast, a different pattern arises in the karst landscape in southwest Florida (Big Cypress National Preserve; BICY), where low-relief and a shallow aquiclude govern regional hydrology. There, the landscape pattern is highly regular (Fig. 1), with circular cypress-dominated wetlands occupying depressions that are hydrologically isolated and distributed evenly in a matrix of pine uplands. Regular landscape patterning results from spatially coupled feedbacks, one positive operating locally that expands patches coupled to another negative that operates at distance, eventually inhibiting patch expansion. The positive feedback in BICY is thought to derive from the presence of surface depressions, which sustain prolonged inundation in this low-relief setting, and facilitate wetland development that greatly augments dissolution potential of infiltrating water in response to ecosystem metabolic processes. In short, wetlands "drill" into the carbonate leading to both vertical and lateral basin expansion. Wetland expansion occurs at the expense of surrounding upland area, which is the local catchment that subsidizes water availability. A distal inhibitory feedback on basin expansion thus occurs as the water necessary to sustain prolonged inundation becomes limiting. The implied strong reciprocal coupling between surface production of organic matter and patterns of induced subsurface carbonate dissolution are a novel example of co-evolving biogeomorphic processes in the earth system. Fig. 1 - Regular patterned landscape in Big Cypress National Preserve showing cypress dominated wetlands (round features) embedded in a mosaic of pine and grass uplands. Exposed carbonate rings are evident at the margins of many of the wetland basins.

Welding and Weldability of AZ31B by Gas Tungsten Arc and Laser Beam Welding Processes

NASA Astrophysics Data System (ADS)

Lathabai, S.; Barton, K. J.; Harris, D.; Lloyd, P. G.; Viano, D. M.; McLean, A.

Welding will play an important role in the fabrication of modular lightweight structures based on magnesium alloy die castings, extrusion profiles and wrought products. Minimisation of rejection rates during fabrication requires that satisfactory weldability be established for a particular combination of materials and welding procedures. In this paper, we present the results of a study to quantify the weldability of wrought alloy AZ31B by gas tungsten arc (GTA) and laser beam (LB) welding processes. The susceptibility to weld metal solidification cracking was evaluated using the Circular Patch weldability test. Operating windows of welding parameters for crack-free and porosity-free GTA and LB welding were identified, based on which welding procedures were developed for sheet and plate AZ31B. The microstructure and mechanical properties of welded test plates were assessed, leading to a better understanding of microstructurat development and structure-property relationships in GTA and LB weldments in AZ31B.

Swarming Patterns in a Two-Dimensional Kinematic Model for Biological Groups

NASA Astrophysics Data System (ADS)

Topaz, Chad

2004-03-01

We construct a continuum model for the motion of biological organisms experiencing social interactions and study its pattern-forming behavior. The model takes the form of a conservation law in two spatial dimensions. Social interactions are modeled in the velocity term, which is nonlocal in the population density. The dynamics of the model may be uniquely decomposed into incompressible motion and potential motion. For the purely incompressible case, the model resembles that for fluid dynamical vortex patches. There exist solutions that have constant population density and compact support for all time. Numerical simulations produce rotating structures with circular cores and spiral arms, reminiscent of naturally observed swarms such as ant mills. For the purely potential case, the model resembles a nonlocal (forwards or backwards) porous media equation, describing aggregation or dispersion of the population. For the aggregative case, the population clumps into regions of high and low density with a predictable characteristic length scale that is confirmed by numerical simulations.

A Double-Negative Metamaterial-Inspired Mobile Wireless Antenna for Electromagnetic Absorption Reduction

PubMed Central

Alam, Touhidul; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2015-01-01

A double-negative metamaterial-inspired antenna is presented for mobile wireless applications. The antenna consists of a semi-circular radiating patch and a 3 × 4 hexagonal shaped metamaterial unit cell array in the ground plane. The antenna is fed with a 50 Ω microstrip feed line. The electric dimensions of the proposed antenna are 0.20λ × 0.26λ × 0.004λ, at the low-end frequency. The proposed antenna achieves a −10 dB impedance with a bandwidth of 2.29 GHz at the lower band and 1.28 GHz at the upper band and can operate for most of the mobile applications such as upper GSM bands, WiMAX, Bluetooth, and wireless local area network (WLAN) frequency bands. The focused novelties of the proposed antenna are its small size, multi-standard operating bands, and electromagnetic absorption reduction at all the operating frequencies using the double-negative metamaterial ground plane. PMID:28793474

Rings of non-spherical, axisymmetric bodies

NASA Astrophysics Data System (ADS)

Gupta, Akash; Nadkarni-Ghosh, Sharvari; Sharma, Ishan

2018-01-01

We investigate the dynamical behavior of rings around bodies whose shapes depart considerably from that of a sphere. To this end, we have developed a new self-gravitating discrete element N-body code, and employed a local simulation method to simulate a patch of the ring. The central body is modeled as a symmetric (oblate or prolate) ellipsoid, or defined through the characteristic frequencies (circular, vertical, epicyclic) that represent its gravitational field. Through our simulations we explore how a ring's behavior - characterized by dynamical properties like impact frequency, granular temperature, number density, vertical thickness and radial width - varies with the changing gravitational potential of the central body. We also contrast properties of rings about large central bodies (e.g. Saturn) with those of smaller ones (e.g. Chariklo). Finally, we investigate how the characteristic frequencies of a central body, restricted to being a solid of revolution with an equatorial plane of symmetry, affect the ring dynamics. The latter process may be employed to qualitatively understand the dynamics of rings about any symmetric solid of revolution.

A Compact Multiple Notched Ultra-Wide Band Antenna with an Analysis of the CSRR-TO-CSRR Coupling for Portable UWB Applications.

PubMed

Rahman, MuhibUr; Ko, Dong-Sik; Park, Jung-Dong

2017-09-25

We present a compact ultra-wideband (UWB) antenna integrated with sharp notches with a detailed analysis of the mutual coupling of the multiple notch resonators. By utilizing complementary split ring resonators (CSRR) on the radiating semi-circular patch, we achieve the sharp notch-filtering of various bands within the UWB band without increasing the antenna size. The notched frequency bands include WiMAX, INSAT, and lower and upper WLAN. In order to estimate the frequency shifts of the notch due to the coupling of the nearby CSRRs, an analysis of the coupling among the multiple notch resonators is carried out and we construct the lumped-circuit equivalent model. The time domain analysis of the proposed antenna is performed to show its validity on the UWB application. The measured frequency response of the input port corresponds quite well with the calculations and simulations. The radiation pattern of the implemented quad-notched UWB antenna is nearly omnidirectional in the passband.

A Compact Multiple Notched Ultra-Wide Band Antenna with an Analysis of the CSRR-TO-CSRR Coupling for Portable UWB Applications

PubMed Central

Ko, Dong-Sik

2017-01-01

We present a compact ultra-wideband (UWB) antenna integrated with sharp notches with a detailed analysis of the mutual coupling of the multiple notch resonators. By utilizing complementary split ring resonators (CSRR) on the radiating semi-circular patch, we achieve the sharp notch-filtering of various bands within the UWB band without increasing the antenna size. The notched frequency bands include WiMAX, INSAT, and lower and upper WLAN. In order to estimate the frequency shifts of the notch due to the coupling of the nearby CSRRs, an analysis of the coupling among the multiple notch resonators is carried out and we construct the lumped-circuit equivalent model. The time domain analysis of the proposed antenna is performed to show its validity on the UWB application. The measured frequency response of the input port corresponds quite well with the calculations and simulations. The radiation pattern of the implemented quad-notched UWB antenna is nearly omnidirectional in the passband. PMID:28946658

Mars Under the Microscope (stretched)

NASA Technical Reports Server (NTRS)

2004-01-01

This magnified look at the martian soil near the Mars Exploration Rover Opportunity's landing site, Meridiani Planum, shows coarse grains sprinkled over a fine layer of sand. The image was captured on the 10th day, or sol, of the rover's mission by its microscopic imager, located on the instrument deployment device, or 'arm.' Scientists are intrigued by the spherical rocks, which can be formed by a variety of geologic processes, including cooling of molten lava droplets and accretion of concentric layers of material around a particle or 'seed.'

The examined patch of soil is 3 centimeters (1.2 inches) across. The circular grain in the lower left corner is approximately 3 millimeters (.12 inches) across, or about the size of a sunflower seed.

This stretched color composite was obtained by merging images acquired with the orange-tinted dust cover open and closed. The varying hints of orange suggest differences in mineral composition. The blue tint at the lower right corner is a tag used by scientists to indicate that the dust cover is closed.

Mars Under the Microscope (color)

NASA Technical Reports Server (NTRS)

2004-01-01

This magnified look at the martian soil near the Mars Exploration Rover Opportunity's landing site, Meridiani Planum, shows coarse grains sprinkled over a fine layer of sand. The image was captured by the rover's microscopic imager on the 10th day, or sol, of its mission and roughly approximates the color a human eye would see. Scientists are intrigued by the spherical rocks, which can be formed by a variety of geologic processes, including cooling of molten lava droplets and accretion of concentric layers of material around a particle or 'seed.'

The examined patch of soil is 3 centimeters (1.2 inches) across. The circular grain in the lower left corner is approximately 3 millimeters (.12 inches) across, or about the size of a sunflower seed.

This color composite was obtained by merging images acquired with the orange-tinted dust cover in both its open and closed positions. The blue tint at the lower right corner is a tag used by scientists to indicate that the dust cover is closed.

High Rate User Ka-Band Phased Array Antenna Test Results

NASA Technical Reports Server (NTRS)

Caroglanian, Armen; Perko, Kenneth; Seufert, Steve; Dod, Tom; Warshowsky, Jay; Day, John H. (Technical Monitor)

2001-01-01

The High Rate User Phased Array Antenna (HRUPAA) is a Ka-Band planar phased array designed by the Harris Corporation for the NASA Goddard Space Flight Center. The HRUPAA permits a satellite to downlink data either to a ground station or through the Tracking and Data Relay Satellite System (TDRSS). The HRUPAA is scanned electronically by ground station / user satellite command over a 120 degree cone angle. The phased array has the advantage of not imparting attitude disturbances to the user spacecraft. The 288-element transmit-only array has distributed RF amplifiers integrated behind each of the printed patch antenna elements. The array has 33 dBW EIRP and is left-hand circularly polarized. An engineering model of a partially populated array has been developed and delivered to NASA Goddard Space Flight Center. This report deals with the testing of the engineering model at the Goddard Antenna Range near-field and compact range facilities. The antenna specifications are described first, followed by the test plan and test results.

Ultra-broadband and high-efficiency polarization conversion metasurface with multiple plasmon resonance modes

NASA Astrophysics Data System (ADS)

Dong, Guo-Xiang; Shi, Hong-Yu; Xia, Song; Li, Wei; Zhang, An-Xue; Xu, Zhuo; Wei, Xiao-Yong

2016-08-01

In this paper, we present a novel metasurface design that achieves a high-efficiency ultra-broadband cross polarization conversion. The metasurface is composed of an array of unit resonators, each of which combines an H-shaped structure and two rectangular metallic patches. Different plasmon resonance modes are excited in unit resonators and allow the polarization states to be manipulated. The bandwidth of the cross polarization converter is 82% of the central frequency, covering the range from 15.7 GHz to 37.5 GHz. The conversion efficiency of the innovative new design is higher than 90%. At 14.43 GHz and 40.95 GHz, the linearly polarized incident wave is converted into a circularly polarized wave. Project supported by the National Natural Science Foundation of China (Grant Nos. 61471292, 61331005, 61471388, 51277012, 41404095, and 61501365), the 111 Project, China (Grant No. B14040), the National Basic Research Program of China (Grant No. 2015CB654602), and the China Postdoctoral Science Foundation ( Grant No. 2015M580849).

Radial microstrip slotline feed network for circular mobile communications array

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Kelly, Eron S.; Lee, Richard Q.; Taub, Susan R.

1994-01-01

In mobile and satellite communications there is a need for low cost and low profile antennas which have a toroidal pattern. Antennas that have been developed for mobile communications include a L-Band electronically steered stripline phased array, a Ka-Band mechanically steered elliptical reflector antenna and a Ka-Band printed dipole. In addition, a L-Band mechanically steered microstrip array, a L-Band microstrip phased array tracking antenna for mounting on a car roof and an X-Band radial line slotted waveguide antenna have been demonstrated. In the above electronically scanned printed arrays, the individual element radiates normally to the plane of the array and hence require a phase shifter to scan the beam towards the horizon. Scanning in the azimuth is by mechanical or electronic steering. An alternate approach is to mount microstrip patch radiators on the surface of a cone to achieve the required elevation angle. The array then scans in the azimuth by beam switching.

Habitat quality and geometry affect patch occupancy of two Orthopteran species.

PubMed

Pasinelli, Gilberto; Meichtry-Stier, Kim; Birrer, Simon; Baur, Bruno; Duss, Martin

2013-01-01

Impacts of habitat loss and fragmentation on distribution and population size of many taxa are well established. In contrast, less is known about the role of within-patch habitat quality for the spatial dynamics of species, even though within-patch habitat quality may substantially influence the dynamics of population networks. We studied occurrence patterns of two Orthopteran species in relation to size, isolation and quality of habitat patches in an intensively managed agricultural landscape (16.65 km(2)) in the Swiss lowland. Occurrence of field crickets (Gryllus campestris) was positively related to patch size and negatively to the distance to the nearest occupied patch, two measures of patch geometry. Moreover, field crickets were more likely to occur in extensively managed meadows, meadows used at low intensity and meadows dominated by Poa pratensis, three measures of patch quality. Occurrence of the large gold grasshopper (Chrysochraon dispar) was negatively related to two measures of patch geometry, distance to the nearest occupied patch and perimeter index (ratio of perimeter length to patch area). Further, large gold grasshoppers were more likely to occupy patches close to water and patches with vegetation left uncut over winter, two measures of patch quality. Finally, examination of patch occupancy dynamics of field crickets revealed that patches colonized in 2009 and patches occupied in both 2005 and 2009 were larger, better connected and of other quality than patches remaining unoccupied and patches from which the species disappeared. The strong relationships between Orthopteran occurrence and aspects of patch geometry found in this study support the "area-and-isolation paradigm". Additionally, our study reveals the importance of patch quality for occurrence patterns of both species, and for patch occupancy dynamics in the field cricket. An increased understanding of patch occupancy patterns may be gained if inference is based on variables related to both habitat geometry and quality.

New contraceptive patch wearability assessed by investigators and participants in a randomized phase 3 study.

PubMed

Kaunitz, Andrew M; Portman, David; Westhoff, Carolyn L; Mishell, Daniel R; Archer, David F; Foegh, Marie

2015-03-01

To evaluate skin irritation and patch adhesiveness of a new weekly low-dose levonorgestrel (LNG) and ethinyl estradiol (EE) contraceptive patch (LNG/EE patch). This analysis was part of an open-label, parallel-group, multicenter, phase 3 study that randomized healthy women to the LNG/EE patch (one patch weekly for three consecutive weeks, followed by a patch-free week for 13 cycles) or to an oral contraceptive for six cycles followed by seven LNG/EE patch cycles. Participants selected patch application sites of abdomen, buttock or upper torso. Investigators rated patch adhesiveness and skin irritation using standardized scales. Participants rated skin irritation and itching daily using standardized scales and recorded patch fall-off on daily diary cards. A total of 32,508 patches were applied (n=1273). At the five clinic visits in which investigators rated the patches, they rated adhesiveness=0 (no lift) for ≥84% of participants and skin irritation=absent/mild for 97% of patches. Participants reported that 2-3.7% of patches fell off and rated skin irritation as absent or mild for 92- 95% of patches, according to site. Investigator- and participant-rated assessments of LNG/EE patch adhesiveness and irritation demonstrated a low incidence of patch detachment, skin irritation and pruritus. This secondary analysis of a phase 3 clinical trial of a new weekly low-dose LNG and EE contraceptive patch, which used assessment by both investigators and participants, observed a low incidence of skin irritation, pruritus and patch detachment. Copyright © 2015 Elsevier Inc. All rights reserved.

Mating success of males with and without wing patch in Drosophila biarmipes.

PubMed

Hegde, S N; Chethan, B K; Krishna, M S

2005-10-01

Some males of D. biarmipes--synonym of D. rajasekari and D. raychaudhuri have a black patch on the wing. The patch extends from the apical margin of wing to the third longitudinal vein. Field and laboratory studies have been carried out in D. biarmipes to study role of male's wing patch in mating success. The field study shows that nature favors D. biarmipes males with patch. Although males without patch mated, males with patch have higher mating success suggesting the role of wing patch during courtship. Further, among mating males, males with patch had longer wings than males without patch. During courtship, males with patch oriented and mated faster; performed courtship acts such as tapping, scissoring, vibration, licking and twist dance more times than males without patch in both competitive and non-competitive situations. The results indicate that there is a casual relationship between the presence of wing patch, mating speed and success. Also there is a correlation between presence of wing patch, size of the flies and mating success.

Lipase in aqueous-polar organic solvents: Activity, structure, and stability

PubMed Central

Kamal, Md Zahid; Yedavalli, Poornima; Deshmukh, Mandar V; Rao, Nalam Madhusudhana

2013-01-01

Studying alterations in biophysical and biochemical behavior of enzymes in the presence of organic solvents and the underlying cause(s) has important implications in biotechnology. We investigated the effects of aqueous solutions of polar organic solvents on ester hydrolytic activity, structure and stability of a lipase. Relative activity of the lipase monotonically decreased with increasing concentration of acetone, acetonitrile, and DMF but increased at lower concentrations (upto ∼20% v/v) of dimethylsulfoxide, isopropanol, and methanol. None of the organic solvents caused any appreciable structural change as evident from circular dichorism and NMR studies, thus do not support any significant role of enzyme denaturation in activity change. Change in 2D [15N, 1H]-HSQC chemical shifts suggested that all the organic solvents preferentially localize to a hydrophobic patch in the active-site vicinity and no chemical shift perturbation was observed for residues present in protein's core. This suggests that activity alteration might be directly linked to change in active site environment only. All organic solvents decreased the apparent binding of substrate to the enzyme (increased Km); however significantly enhanced the kcat. Melting temperature (Tm) of lipase, measured by circular dichroism and differential scanning calorimetry, altered in all solvents, albeit to a variable extent. Interestingly, although the effect of all organic solvents on various properties on lipase is qualitatively similar, our study suggest that magnitudes of effects do not appear to follow bulk solvent properties like polarity and the solvent effects are apparently dictated by specific and local interactions of solvent molecule(s) with the protein. PMID:23625694

Unique Microbial Phylotypes in Namib Desert Dune and Gravel Plain Fairy Circle Soils.

PubMed

van der Walt, Andries J; Johnson, Riegardt M; Cowan, Don A; Seely, Mary; Ramond, Jean-Baptiste

2016-08-01

Fairy circles (FCs) are barren circular patches of soil surrounded by grass species. Their origin is poorly understood. FCs feature in both the gravel plains and the dune fields of the Namib Desert. While a substantial number of hypotheses to explain the origin and/or maintenance of fairy circles have been presented, none are completely consistent with either their properties or their distribution. In this study, we investigated the hypothesis that FC formation in dunes and gravel plains is due to microbial phytopathogenesis. Surface soils from five gravel plain and five dune FCs, together with control soil samples, were analyzed using high-throughput sequencing of bacterial/archaeal (16S rRNA gene) and fungal (internal transcribed spacer [ITS] region) phylogenetic markers. Our analyses showed that gravel plain and dune FC microbial communities are phylogenetically distinct and that FC communities differ from those of adjacent vegetated soils. Furthermore, various soil physicochemical properties, particularly the pH, the Ca, P, Na, and SO4 contents, the soil particle size, and the percentage of carbon, significantly influenced the compositions of dune and gravel plain FC microbial communities, but none were found to segregate FC and vegetated soil communities. Nevertheless, 9 bacterial, 1 archaeal, and 57 fungal phylotypes were identified as FC specific, since they were present within the gravel plain and dune FC soils only, not in the vegetated soils. Some of these FC-specific phylotypes were assigned to taxa known to harbor phytopathogenic microorganisms. This suggests that these FC-specific microbial taxa may be involved in the formation and/or maintenance of Namib Desert FCs. Fairy circles (FCs) are mysterious barren circular patches of soil found within a grass matrix in the dune fields and gravel plains of the Namib Desert. Various hypotheses attempting to explain this phenomenon have been proposed. To date, however, none have been successful in fully explaining the etiology of FCs, particularly since gravel plain FCs have been largely ignored. In this study, we investigated the hypothesis that microorganisms could be involved in the FC phenomenon through phytopathogenesis. We show that the microbial communities in FC and control vegetated soil samples were significantly different. Furthermore, we detected 67 FC-specific microbial phylotypes, i.e., phylotypes present solely in both gravel plain and dune FC soils, some of which were closely related to known phytopathogens. Our results, therefore, demonstrate that microorganisms may play a role in the formation and/or maintenance of Namib Desert FCs, possibly via phytopathogenic activities. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Multi-band Microwave Antennas and Devices based on Generalized Negative-Refractive-Index Transmission Lines

NASA Astrophysics Data System (ADS)

Ryan, Colan Graeme Matthew

Focused on the quad-band generalized negative-refractive-index transmission line (G-NRI-TL), this thesis presents a variety of novel printed G-NRI-TL multi-band microwave device and antenna prototypes. A dual-band coupled-line coupler, an all-pass G-NRI-TL bridged-T circuit, a dual-band metamaterial leaky-wave antenna, and a multi-band G-NRI-TL resonant antenna are all new developments resulting from this research. In addition, to continue the theme of multi-band components, negative-refractive-index transmission lines are used to create a dual-band circularly polarized transparent patch antenna and a two-element wideband decoupled meander antenna system. High coupling over two independently-specified frequency bands is the hallmark of the G-NRI-TL coupler: it is 0.35lambda0 long but achieves approximately -3 dB coupling over both bands with a maximum insertion loss of 1 dB. This represents greater design flexibility than conventional coupled-line couplers and less loss than subsequent G-NRI-TL couplers. The single-ended bridged-T G-NRI-TL offers a metamaterial unit cell with an all-pass magnitude response up to 8 GHz, while still preserving the quad-band phase response of the original circuit. It is shown how the all-pass response leads to wider bandwidths and improved matching in quad-band inverters, power dividers, and hybrid couplers. The dual-band metamaterial leaky-wave antenna presented here was the first to be reported in the literature, and it allows broadside radiation at both 2 GHz and 6 GHz without experiencing the broadside stopband common to conventional periodic antennas. Likewise, the G-NRI-TL resonant antenna is the first reported instance of such a device, achieving quad-band operation between 2.5 GHz and 5.6 GHz, with a minimum radiation efficiency of 80%. Negative-refractive-index transmission line loading is applied to two devices: an NRI-TL meander antenna achieves a measured 52% impedance bandwidth, while a square patch antenna incorporates NRI-TL elements to achieve circular polarization at 2.3 GHz and 2.7 GHz, with radiation efficiencies of 70% and 78%, respectively. Optical transparency of 50% is then realized by cutting a grid through the antenna and substrate, making the device suitable for direct integration with solar panels. Therefore, this research provides several proof-of-concept devices to highlight the flexibility and multi-band properties of the G-NRI-TL which extend the capabilities of microwave transceiver systems.

Pretreatment of pericardial patches with antibiotics does not alter patch healing in vivo.

PubMed

Bai, Hualong; Kuwahara, Go; Wang, Mo; Brownson, Kirstyn E; Foster, Trenton R; Yamamoto, Kota; Xing, Ying; Dardik, Alan

2016-04-01

Pretreatment with antibiotics is commonly performed before surgical implantation of prosthetic materials. We previously showed that pericardial patches are infiltrated by macrophages and arterial stem cells after implantation into an artery. We hypothesized that antibiotic pretreatment would diminish the number of cells infiltrating into the patch, potentially affecting early neointimal formation. Bovine pericardial patches were pretreated with saline, bacitracin (500 U/mL), or cephalexin (10 mg/mL) for 30 minutes before implantation into the Wistar rat infrarenal aorta. Patches were retrieved on day 7 or day 30 and analyzed for histology and cell infiltration. Markers of proliferation, apoptosis, vascular cell identity, and M1 and M2 macrophage subtypes were examined using immunofluorescence and immunohistochemistry. Extracted proteins were analyzed by Western blot. At day 7, pericardial patches pretreated with bacitracin or cephalexin showed similar amounts of neointimal thickening (P = .55) and cellular infiltration (P = .42) compared with control patches. Patches pretreated with antibiotics showed similar proliferation (P = .09) and apoptosis (P = .84) as control patches. The cell composition of the neointima in pretreated patches was similar to control patches, with a thin endothelial layer overlying a thin layer of smooth muscle cells (P = .45), and containing similar numbers of CD34-positive (P = .26) and vascular endothelial growth factor receptor 2-positive (P = .31) cells. Interestingly, within the body of the patch, there were fewer macrophages (P = .0003) and a trend towards fewer endothelial progenitor cells (P = .051). No M1 macrophages were found in or around any of the patches. M2 macrophages were present around the patches, and there was no difference in numbers of M2 macrophages surrounding control patches and patches pretreated with antibiotics (P = .24). There was no difference in neointimal thickness at day 30 between control patches and patches pretreated with antibiotics (P = .52). Pretreatment of bovine pericardial patches with the antibiotics bacitracin or cephalexin has no detrimental effect on early patch healing, with similar neointimal thickness, cellular infiltration, and numbers of M2 macrophages compared with control patches. These results suggest that the host vessel response to patch angioplasty using pericardial patches is adaptive remodeling (eg, arterial healing). Published by Elsevier Inc.

Patch dynamics and the timing of colonization-abandonment events by male Kirtland’s Warblers in an early succession habitat

USGS Publications Warehouse

Donner, Deahn M.; Ribic, Christine; Probst, John R.

2010-01-01

Habitat colonization and abandonment affects the distribution of a species in space and time, ultimately influencing the duration of time habitat is used and the total area of habitat occupied in any given year. Both aspects have important implications to long-term conservation planning. The importance of patch isolation and area to colonization–extinction events is well studied, but little information exists on how changing regional landscape structure and population dynamics influences the variability in the timing of patch colonization and abandonment events. We used 26 years of Kirtland’s Warbler (Dendroica kirtlandii) population data taken during a habitat restoration program (1979–2004) across its historical breeding range to examine the influence of patch attributes and temporal large-scale processes, specifically the rate of habitat turnover and fraction of occupied patches, on the year-to-year timing of patch colonization and abandonment since patch origin. We found the timing of patch colonization and abandonment was influenced by patch and large-scale regional factors. In this system, larger patches were typically colonized earlier (i.e., at a younger age) and abandoned later than smaller patches. Isolated patches (i.e., patches farther from another occupied patch) were generally colonized later and abandoned earlier. Patch habitat type affected colonization and abandonment; colonization occurred at similar patch ages between plantation and wildfire areas (9 and 8.5 years, respectively), but plantations were abandoned at earlier ages (13.9 years) than wildfire areas (16.4 years) resulting in shorter use. As the fraction of occupied patches increased, patches were colonized and abandoned at earlier ages. Patches were abandoned at older ages when the influx of new habitat patches was at low and high rates. Our results provide empirical support for the temporal influence of patch dynamics (i.e., patch destruction, creation, and succession) on local colonization and extinction processes that help explain large-scale patterns of habitat occupancy. Results highlight the need for practitioners to consider the timing of habitat restoration as well as total amount and spatial arrangement of habitat to sustain populations.

Ethinyl Estradiol and Norelgestromin Transdermal Patch

MedlinePlus

... the skin. One patch is applied once a week for 3 weeks, followed by a patch-free week. Follow the directions on your prescription label carefully, ... new patch on the same day of the week (the Patch Change Day). Apply a new patch ...

Patch occupancy and dispersal of spruce grouse on the edge of its range in Maine

USGS Publications Warehouse

Whitcomb, S.A.; Servello, F.A.; O'Connell, A.F.

1996-01-01

We surveyed 18 habitat patches (black spruce (Picea marinana) - tamarack (Larix larcina) wetlands) for spruce grouse (Dendragapus canadensis canadensis) on Mount Desert Island, Maine, during April-May in 1992 and 1993 to determine patch occupancy relative to patch area. We also equipped nine juvenile grouse with radio transmitters to determine movement and habitat use outside of patches during autumn dispersal. The 2 large patches (77 and 269 ha), 5 of 6 medium-sized (11-26 ha) patches, and 1 of 10 small (4-8 ha) patches were occupied. Spruce grouse occupied smaller habitat patches than previously reported, and occupied patches were closer (P < 0.05) to the nearest occupied patch (x = 1.2 km) than were unoccupied patches (x = 2.5 km). Eight of nine juvenile grouse left their natal habitat patch during autumn dispersal, and net dispersal distance (x = 2.3 km) was greater than that reported for grouse in areas with more contiguous habitat. Dispersing juveniles used all major forest types and 33 % of relocations were in deciduous forest. Thus, deciduous forest was not an absolute dispersal barrier.

Runoff and erosion in a pinon-juniper woodland: Influence of vegetation patches

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

Reid, K.D.; Wilcox, B.P.; Breshears, D.D.

1999-12-01

In many semiarid regions, runoff and erosion differ according to vegetation patch type. These differences, although hypothesized to fundamentally affect ecological processes, have been poorly quantified. In a semiarid pinion-juniper woodland [Pinus edulis Engelm. and Juniperus monosperma (Engelm) Sarg.] in northern New Mexico, the authors measured runoff and erosion from the three patch types that compose these woodlands: Canopy patches (those beneath woody plants), vegetated patched in intercanopy areas, and bare patches in intercanopy areas. The bare intercanopy patches exhibited the highest rates, followed by vegetated intercanopy patches and then by canopy patches. Large convective summer storms, though relatively infrequent,more » generated much of the runoff and most of the sediment; prolonged frontal storms were capable of generating considerable runoff but little sediment. A portion of the runoff and most of the sediment generated from bare intercanopy patches was redistributed down-slope, probably to adjacent vegetated intercanopy patches, demonstrating connectivity between these two patch types. Their results indicate that there are significant and important differences in runoff and sediment production from the three patch types; that bare intercanopy patches act as sources of both water and sediment for the vegetated intercanopy patches; and that the transfer of water and sediment at small scales is both frequent enough and substantial enough to be considered ecologically significant.« less

Multi-scale heterogeneity of the 2011 Great Tohoku-oki Earthquake from dynamic simulations

NASA Astrophysics Data System (ADS)

Aochi, H.; Ide, S.

2011-12-01

In order to explain the scaling issues of earthquakes of different sizes, multi-scale heterogeneity conception is necessary to characterize earthquake faulting property (Ide and Aochi, JGR, 2005; Aochi and Ide, JGR, 2009).The 2011 Great Tohoku-oki earthquake (M9) is characterized by a slow initial phase of about M7, a M8 class deep rupture, and a M9 main rupture with quite large slip near the trench (e.g. Ide et al., Science, 2011) as well as the presence of foreshocks. We dynamically model these features based on the multi-scale conception. We suppose a significantly large fracture energy (corresponding to slip-weakening distance of 3.2 m) in most of the fault dimension to represent the M9 rupture. However we give local heterogeneity with relatively small circular patches of smaller fracture energy, by assuming the linear scaling relation between the radius and fracture energy. The calculation is carried out using 3D Boundary Integral Equation Method. We first begin only with the mainshock (Aochi and Ide, EPS, 2011), but later we find it important to take into account of a series of foreshocks since the 9th March (M7.4). The smaller patches including the foreshock area are necessary to launch the M9 rupture area of large fracture energy. We then simulate the ground motion in low frequencies using Finite Difference Method. Qualitatively, the observed tendency is consistent with our simulations, in the meaning of the transition from the central part to the southern part in low frequencies (10 - 20 sec). At higher frequencies (1-10 sec), further small asperities are inferred in the observed signals, and this feature matches well with our multi-scale conception.

Geochemical factors promoting die-back gap formation in colonizing patches of Spartina densiflora in an irregularly flooded marsh

NASA Astrophysics Data System (ADS)

Mirlean, Nicolai; Costa, Cesar S. B.

2017-04-01

Circular (RP) and ring-shape (RP) patches of vegetation in intertidal flats have been associated with the radial expansion of tussock growth forms and die-back gap in older central stands, respectively. RP formation has not yet been sufficiently explained. We accomplished a comparative geochemical study of CP and RP structures of Spartina densiflora within a single saltmarsh in a microtidal estuary (<0.5 m). The pore water under these structures demonstrated distinctive physical-chemical properties by marked seasonal changing in water level and salinity. During high-water period dissolved H2S was frequently low in pore waters of S. densiflora structures due to reactive-Fe, which scavenge the sulfide from solution and form solid sulfides. During less flooded-brackish water period, pore water pH goes down below 4 inside the vegetated bordering areas of RP. In these locations the concentration of soluble sulfides dramatically increases up to 140 μM L-1. The high concentration of protons in pore water is the result of solid sulfides atmospheric oxidation to sulfuric acid. High dissolution of H2S, along with the low pH, creates a toxic environment for S. densiflora and die-back central gap formation in RP. CP structure was 5 cm higher in the intertidal than RP but shows frequent presence of a water layer, less severe oxidation of sulfides and limited building-up of toxic condition to plants. Development of S. densiflora RP probably indicates the uplift of sediment by this bioengineer grass and/or periodic lowering of the water surface below a certain critical level.

Fractal-Inspired Subwavelength Geometric Inclusions for Improvement of High-Frequency Electromagnetic Devices

NASA Astrophysics Data System (ADS)

Smith, Kathryn Leigh

This dissertation presents research results demonstrating the efficacy of fractal-inspired subwavelength geometric inclusions for improvement of high-frequency electromagnetic devices. It begins with a review of the open literature in the area of fractal applications in antennas and metamaterials. This is followed by a detailed discussion of three high-frequency electromagnetic devices that demonstrate performance improvement through incorporation of subwavelength geometric design elements. The first of these devices is a spherical spiral metamaterial unit cell that was developed as a three-dimensional fractal expansion of the traditional split ring resonator, and is shown to be capable of producing broadband negative permeability, negative permittivity, or both, depending solely on the orientation of the unit cells with respect to the incident electric field. The second device is a ringed rectangular patch antenna that has four resonant frequencies. All four of these operative frequencies are shown to produce similar radiation patterns, which also closely match the pattern of a traditional patch antenna. Several minor geometric modifications of the basic shape of the device are also presented, and are shown to enable modification of the number of resonances, as well as tuning of frequencies of resonance. The third and final topic is a modified horn antenna that incorporates a spiral metamaterial as a phase-shifting device in order to achieve circularly polarized radiation. The handedness of the radiated wave is shown to be tunable through simple reorientation of the loading unit cells. In each of these cases, electrically-small geometric modification of existing device geometries is shown to greatly affect performance, either by increasing bandwidth, by inducing multiband behavior, or by enabling exotic radiation characteristics.

Topographic effects on dispersal patterns of Phytophthora cinnamomi at a stand scale in a Spanish heathland

PubMed Central

Acedo, Angel; Abad, Enrique

2018-01-01

Phytophthora cinnamomi is one of the most important plant pathogens in the world, causing root rot in more than a thousand plant species. This observational study was carried out on a P. cinnamomi infected heathland of Erica umbellata used as goat pasture. The patterns and shapes of disease foci and their distribution were described in a spatial and temporal context using an aerial photograph record. A set of topographic traits was selected on the basis of a disease dynamic hypothesis and their effects on observed spatial disease patterns were analyzed. Incipient infections situated in flat terrain expanded as compact circular front patterns with a low growth rate. On slopes, disease patches developed more rapidly down slope, forming parabolic shapes. The axis direction of the parabolas was highly correlated with terrain aspect, while the parabolic amplitude was associated with land curvature and slope. New secondary foci appeared over the years producing an accelerated increase of the affected surface. These new foci were observed in sites where disease density was higher or near sites more frequently visited by animals such as the stable or the forage crop. In contrast, a smaller number of disease foci occur in areas which animals are reluctant to visit, such as where they have a short range of vision. Our results suggest that 1) the growth of existing P. cinnamomi foci is controlled by a combination of root-to-root contact and water flows, 2) the increase in the diseased area arises mainly from the multiplication of patches, 3) the formation of new foci is mediated by long-distance transport due to the movement of animals and humans along certain preferential pathways, and 4) geomorphology and topography traits are associated with the epidemiology of this soil-borne pathogen. PMID:29601576

THE HANLE AND ZEEMAN POLARIZATION SIGNALS OF THE SOLAR Ca II 8542 Å LINE

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

Štěpán, Jiri; Bueno, Javier Trujillo

We highlight the main results of a three-dimensional (3D) multilevel radiative transfer investigation about the solar disk-center polarization of the Ca ii 8542 Å line. First, through the use of a 3D model of the solar atmosphere, we investigate the linear polarization that occurs due to the atomic level polarization produced by the absorption and scattering of anisotropic radiation, taking into account the symmetry-breaking effects caused by its thermal, dynamic, and magnetic structure. Second, we study the contribution of the Zeeman effect to the linear and circular polarization. Finally, we show examples of the Stokes profiles produced by the jointmore » action of the atomic level polarization and the Hanle and Zeeman effects. We find that the Zeeman effect tends to dominate the linear polarization signals only in the localized patches of opposite magnetic polarity, where the magnetic field is relatively strong and slightly inclined; outside such very localized patches, the linear polarization is often dominated by the contribution of atomic level polarization. We demonstrate that a correct modeling of this last contribution requires taking into account the symmetry-breaking effects caused by the thermal, dynamic, and magnetic structure of the solar atmosphere, and that in the 3D model used the Hanle effect in forward-scattering geometry (disk-center observation) mainly reduces the polarization corresponding to the zero-field case. We emphasize that, in general, a reliable modeling of the linear polarization in the Ca ii 8542 Å line requires taking into account the joint action of atomic level polarization and the Hanle and Zeeman effects.« less

An extended patch-dynamic framework for food chains in fragmented landscapes

PubMed Central

Liao, Jinbao; Chen, Jiehong; Ying, Zhixia; Hiebeler, David E.; Nijs, Ivan

2016-01-01

Habitat destruction, a key determinant of species loss, can be characterized by two components, patch loss and patch fragmentation, where the former refers to the reduction in patch availability, and the latter to the division of the remaining patches. Classical metacommunity models have recently explored how food web dynamics respond to patch loss, but the effects of patch fragmentation have largely been overlooked. Here we develop an extended patch-dynamic model that tracks the patch occupancy of the various trophic links subject to colonization-extinction-predation dynamics by incorporating species dispersal with patch connectivity. We found that, in a simple food chain, species at higher trophic level become extinct sooner with increasing patch loss and fragmentation due to the constraint in resource availability, confirming the trophic rank hypothesis. Yet, effects of fragmentation on species occupancy are largely determined by patch loss, with maximal fragmentation effects occurring at intermediate patch loss. Compared to the spatially explicit simulations that we also performed, the current model with pair approximation generates similar community patterns especially in spatially clustered landscapes. Overall, our extended framework can be applied to model more complex food webs in fragmented landscapes, broadening the scope of existing metacommunity theory. PMID:27608823

Metal Patch Antenna

NASA Technical Reports Server (NTRS)

Chamberlain, Neil F. (Inventor); Zawadzki, Mark S. (Inventor); Hodges, Richard E. (Inventor)

2012-01-01

Disclosed herein is a patch antenna comprises a planar conductive patch attached to a ground plane by a support member, and a probe connector in electrical communication with the conductive patch arranged to conduct electromagnetic energy to or from the conductive patch, wherein the conductive patch is disposed essentially parallel to the ground plane and is separated from the ground plane by a spacing distance; wherein the support member comprises a plurality of sides disposed about a central axis oriented perpendicular to the conductive patch and the ground plane; wherein the conductive patch is solely supported above the ground plane by the support member; and wherein the support member provides electrical communication between the planer conductive patch and the ground plane.

Light transmission and preference of eye patches for occlusion treatment.

PubMed

Heo, Hwan; Park, Jung Won; Park, Sang Woo

2013-01-01

To investigate light transmission and preference for six eye patches for occlusion therapy. Six patches were examined, including; Ortopad Fun Pack, Ortopad Flesh, Kawamoto A-1, Kawamoto A-2, 3M Opticlude, and Everade Eye Guard. The size and the presence of a light blocking pad of patches were investigated. The amount of light transmitted through the patches was evaluated, using a digital light meter and a model eye, in three different environments; indoors with fluorescent light, outdoors on a sunny day, and strong light from illuminator. After patching the normal eye, the flash visual evoked potential (VEP) was measured. Thirty patients with amblyopia or horizontal strabismus, who received occlusion therapy as initial treatment, were included. After using all six patches, patients completed a 7-item questionnaire regarding the patch preference for size, color and shape, adhesive power, pain with removal, skin irritation after removing patch, parent's preference and overall opinion. All patches had a light-blocking pad, except the 3M Nexcare. Ortopad had the strongest light blocking power in the three environments, and the 3M Nexcare had the weakest power. In flash VEP, Ortopad and Kawamoto patches showed flat, but 3M Nexcare and Everade Eye Guard showed normal response. There were significant preferential differences among the patches in all the items of the questionnaire (P<0.05). In comparison between the patches respectively, 3M Nexcare received the lowest satisfaction in pain when removing a patch and skin irritation after removing a patch. Kawamoto A-2 received the lowest score in the overall satisfaction. We found differences in the light-blocking power and in the preference of the various patches for the occlusion treatment. This is a pilot study regarding only characteristics and preferences of patches. Further clinical studies regarding the relationship between characteristics or preferences of patches and outcomes of occlusion treatment are needed.

Tolerability, usability and acceptability of dissolving microneedle patch administration in human subjects

PubMed Central

Arya, Jaya; Henry, Sebastien; Kalluri, Haripriya; McAllister, Devin V.; Pewin, Winston P.; Prausnitz, Mark R.

2017-01-01

To support translation of microneedle patches from pre-clinical development into clinical trials, this study examined the effect of microneedle patch application on local skin reactions, reliability of use and acceptability to patients. Placebo patches containing dissolving microneedles were administered to fifteen human participants. Microneedle patches were well tolerated in the skin with no pain or swelling and only mild erythema localized to the site of patch administration that resolved fully within seven days. Microneedle patches could be administered by hand without the need of an applicator and delivery efficiencies were similar for investigator-administration and self-administration. Microneedle patch administration was not considered painful and the large majority of subjects were somewhat or fully confident that they self-administered patches correctly. Microneedle patches were overwhelmingly preferred over conventional needle and syringe injection. Altogether, these results demonstrate that dissolving microneedle patches were well tolerated, easily usable and strongly accepted by human subjects, which will facilitate further clinical translation of this technology. PMID:28285193

Context-dependent colonization dynamics: Regional reward contagion drives local compression in aquatic beetles.

PubMed

Pintar, Matthew R; Resetarits, William J

2017-09-01

Habitat selection by colonizing organisms is an important factor in determining species abundance and community dynamics at multiple spatial scales. Many organisms select habitat patches based on intrinsic patch quality, but patches exist in complex landscapes linked by dispersal and colonization, forming metapopulations and metacommunities. Perceived patch quality can be influenced by neighbouring patches through spatial contagion, wherein perceived quality of one patch can extend beyond its borders and either increase or decrease the colonization of neighbouring patches and localities. These spatially explicit colonization dynamics can result in habitat compression, wherein more colonists occupy a patch or locality than in the absence of spatial context dependence. Previous work on contagion/compression focused primarily on the role of predators in driving colonization patterns. Our goal was to determine whether resource abundance can drive multi-scale colonization dynamics of aquatic beetles through the processes of contagion and compression in naturally colonized experimental pools. We established two levels (high/low quality) of within-patch resource abundances (leaf litter) using an experimental landscape of mesocosms, and assayed colonization by 35 species of aquatic beetles. Patches were arranged in localities (sets of two patches), which consisted of a combination of two patch-level resource levels in a 2 × 2 factorial design, allowing us to assay colonization at both locality and patch levels. We demonstrate that patterns of species abundance and richness of colonizing aquatic beetles are determined by patch quality and context-dependent processes at multiple spatial scales. Localities that consisted of at least one high-quality patch were colonized at equivalent rates that were higher than localities containing only low-quality patches, displaying regional reward contagion. In localities that consisted of one high- and one low-quality patch, reward contagion produced by higher leaf litter levels resulted in greater abundance of beetles in such localities, which then compressed into the highest quality patches. Our results provide further support for the critical roles of habitat selection and spatial context, particularly the quality of neighbouring habitat patches, in generating patterns of species abundances and community structure across landscapes. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Species presence frequency and diversity in different patch types along an altitudinal gradient: Larix chinensis Beissn in Qinling Mountains (China).

PubMed

Huang, Minyi; Duan, Renyan; Wang, Shixiong; Wang, Zhigao; Fan, Weiyi

2016-01-01

Forest communities are mosaic systems composed of patches classified into four different developmental patch types: gap patch (G), building patch (B), mature patch (M) and degenerate patch (D). To study the mechanisms maintaining diversity in subalpine coniferous forests, species presence frequency and diversity in the four distinct patch types (G, B, M and D) of Larix chinensis conifer forests at three altitudinal gradients in the Qinling Mountains were analyzed. Our results were as follows: (1) Different species (or functional groups) had distinct presence frequencies in the four different patch types along the altitudinal gradient; (2) Some species or functional groups (species groups sharing similar traits and responses to the environment) only occurred in some specific patches. For seed dispersal, species using wind mainly occurred in G and D, while species using small animals mainly occurred in B and M; (3) Species composition of adjacent patch types was more similar than non-adjacent patch types, based on the lower β diversity index of the former; (4) The maximum numbers of species and two diversity indices (D' and H') were found in the middle altitudes. Various gap-forming processes and dispersal limitation may be the two major mechanisms determining species diversity in Larix chinensis coniferous forests at the patch scale.

LabPatch, an acquisition and analysis program for patch-clamp electrophysiology.

PubMed

Robinson, T; Thomsen, L; Huizinga, J D

2000-05-01

An acquisition and analysis program, "LabPatch," has been developed for use in patch-clamp research. LabPatch controls any patch-clamp amplifier, acquires and records data, runs voltage protocols, plots and analyzes data, and connects to spreadsheet and database programs. Controls within LabPatch are grouped by function on one screen, much like an oscilloscope front panel. The software is mouse driven, so that the user need only point and click. Finally, the ability to copy data to other programs running in Windows 95/98, and the ability to keep track of experiments using a database, make LabPatch extremely versatile. The system requirements include Windows 95/98, at least a 100-MHz processor and 16 MB RAM, a data acquisition card, digital-to-analog converter, and a patch-clamp amplifier. LabPatch is available free of charge at http://www.fhs.mcmaster.ca/huizinga/.

Group-living herbivores weigh up food availability and dominance status when making patch-joining decisions.

PubMed

Stears, Keenan; Kerley, Graham I H; Shrader, Adrian M

2014-01-01

Two key factors that influence the foraging behaviour of group-living herbivores are food availability and individual dominance status. Yet, how the combination of these factors influences the patch-joining decisions of individuals foraging within groups has scarcely been explored. To address this, we focused on the patch-joining decisions of group-living domestic goats (Capra hircus). When individuals were tested against the top four ranked goats of the herd, we found that at patches with low food availability they avoided these dominant patch-holders and only joined subordinates (i.e. costs outweighed benefits). However, as the amount of food increased, the avoidance of the top ranked individuals declined. Specifically, goats shifted and joined the patch of an individual one dominance rank higher than the previous dominant patch holder when the initial quantity of food in the new patch was twice that of the lower ranking individual's patch (i.e. benefits outweighed costs). In contrast, when individuals chose between patches held by dominant goats, other than the top four ranked goats, and subordinate individuals, we found that they equally joined the dominant and subordinate patch-holders. This joining was irrespective of the dominance gap, absolute rank of the dominant patch-holder, sex or food availability (i.e. benefits outweighed costs). Ultimately, our results highlight that herbivores weigh up the costs and benefits of both food availability and patch-holder dominance status when making patch-joining decisions. Furthermore, as the initial quantity of food increases, food availability becomes more important than dominance with regard to influencing patch-joining decisions.

Covalent modification of pericardial patches for sustained rapamycin delivery inhibits venous neointimal hyperplasia

PubMed Central

Bai, Hualong; Lee, Jung Seok; Chen, Elizabeth; Wang, Mo; Xing, Ying; Fahmy, Tarek M.; Dardik, Alan

2017-01-01

Prosthetic grafts and patches are commonly used in cardiovascular surgery, however neointimal hyperplasia remains a significant concern, especially under low flow conditions. We hypothesized that delivery of rapamycin from nanoparticles (NP) covalently attached to patches allows sustained site-specific delivery of therapeutic agents targeted to inhibit localized neointimal hyperplasia. NP were covalently linked to pericardial patches using EDC/NHS chemistry and could deliver at least 360 ng rapamycin per patch without detectable rapamycin in serum; nanoparticles were detectable in the liver, kidney and spleen but no other sites within 24 hours. In a rat venous patch angioplasty model, control patches developed robust neointimal hyperplasia on the patch luminal surface characterized by Eph-B4-positive endothelium and underlying SMC and infiltrating cells such as macrophages and leukocytes. Patches delivering rapamycin developed less neointimal hyperplasia, less smooth muscle cell proliferation, and had fewer infiltrating cells but retained endothelialization. NP covalently linked to pericardial patches are a novel composite delivery system that allows sustained site-specific delivery of therapeutics; NP delivering rapamycin inhibit patch neointimal hyperplasia. NP linked to patches may represent a next generation of tissue engineered cardiovascular implants. PMID:28071663

Effect of novel mucoadhesive buccal patches of carvedilol on isoprenaline-induced tachycardia

PubMed Central

Verma, Navneet; Chattopadhyay, Pronobesh

2014-01-01

The main aim of the study was designed to develop bioadhesive buccal patches of carvedilol (CR) and evaluate for isoprenaline-induced tachycardia. Buccal patches of carvedilol were prepared by using chitosan (CH), sodium salt of carboxy methyl cellulose (NaCMC), and polyvinyl alcohol (PVA) as mucoadhesive polymers. The solvent evaporation method was used for the preparation of buccal patches. The patches were evaluated for their physical characteristics like patch thickness, weight variation, content uniformity, folding endurance, surface pH, residence time, in vitro drug release, and in vivo pharmacodynamic study. The swelling index of the patches was found to be proportional to the polymer concentration, whereas surface pH of all the formulated bioadhesive patches was found to lie between neutral ranges. In-vitro release study shows that 94.75% drug was release in 8 hours from the patch, which containing 2% w/v chitosan. The folding endurance result shows good elasticity in all the patches. Application of buccal patches on buccal mucosa of rabbit shows a significant result in % inhibition of isoprenaline-induced tachycardia. Prepared buccal patches of chitosan, NaCMC, and PVA containing Carvedilol meet the ideal requirement for the delivery of cardiovascular drugs and inhibit the isoprenaline tachycardia. PMID:24959419

Effect of novel mucoadhesive buccal patches of carvedilol on isoprenaline-induced tachycardia.

PubMed

Verma, Navneet; Chattopadhyay, Pronobesh

2014-04-01

The main aim of the study was designed to develop bioadhesive buccal patches of carvedilol (CR) and evaluate for isoprenaline-induced tachycardia. Buccal patches of carvedilol were prepared by using chitosan (CH), sodium salt of carboxy methyl cellulose (NaCMC), and polyvinyl alcohol (PVA) as mucoadhesive polymers. The solvent evaporation method was used for the preparation of buccal patches. The patches were evaluated for their physical characteristics like patch thickness, weight variation, content uniformity, folding endurance, surface pH, residence time, in vitro drug release, and in vivo pharmacodynamic study. The swelling index of the patches was found to be proportional to the polymer concentration, whereas surface pH of all the formulated bioadhesive patches was found to lie between neutral ranges. In-vitro release study shows that 94.75% drug was release in 8 hours from the patch, which containing 2% w/v chitosan. The folding endurance result shows good elasticity in all the patches. Application of buccal patches on buccal mucosa of rabbit shows a significant result in % inhibition of isoprenaline-induced tachycardia. Prepared buccal patches of chitosan, NaCMC, and PVA containing Carvedilol meet the ideal requirement for the delivery of cardiovascular drugs and inhibit the isoprenaline tachycardia.

Food quality and the risk of light exposure affect patch-choice decisions in the slime mold Physarum polycephalum.

PubMed

Latty, Tanya; Beekman, Madeleine

2010-01-01

How individuals deal with multiple conflicting demands is an important aspect of foraging ecology, yet work on foraging behavior has typically neglected neurologically simple organisms. Here we examine the impact of an abiotic risk (light) and energetic status on the foraging decisions of a protist, the slime mold Physarum polycephalum. We examined patch choice in a "non-risky" environment by presenting starved and non-starved P. polycephalum amoebas with a choice between two shaded food patches (one high quality, one low quality). We next examined patch choice in the presence of a conflict between foraging risk (light exposure) and food quality by presenting amoebas with a choice between a shaded, low-quality patch, and a light-exposed, high-quality patch. When both patches were shaded, 100% of amoebas selected the higher quality food patch, irrespective of food-quality differences or the individual's energetic status. When light exposure and food quality conflicted, amoebas selected the patch with the higher food quality when the quality difference between the patches was high. When the quality difference between patches was small, amoebas selected the shaded, lower quality patch.

Ontogenetic changes in accumulation of rhizomes in monoclonal patch of Miscanthus sinensis Anderss. in warm temperate region of Japan.

PubMed

Kobayashi, Katsumi; Yokoi, Yota; Masuzawa, Takehiro

2011-05-01

To determine the main benefits of clonal expansion of Miscanthus sinensis patches (monoclones), we observed the annual pattern of the areal expansion of a number of M. sinensis patches and examined how the quantity of rhizomes in such patches is related to changes in their basal area. To forage for nutriments, a patch must continuously widen its habitat. Patches annually expanded centrifugally by sympodial branching of short rhizomes, which originated in tillering that occurred more than once a year. However, the basal area of the patches approached a ceiling as the patches aged. Both the number and the weight of rhizomes in the patches continued to increase as long as the basal area expanded. The mean weight of rhizomes in patches also initially increased quickly, but then reached a ceiling as the clones expanded. Similarly, the amount of reserve substance per shoot in the patches increased asymptotically along with the clonal expansion, depending on the rhizome mass allotted to each shoot. These results suggest that, in the clonal growth of M. sinensis patches, the accumulation of reserve matter in the rhizomes is more important than foraging in new areas.

Covalent modification of pericardial patches for sustained rapamycin delivery inhibits venous neointimal hyperplasia

NASA Astrophysics Data System (ADS)

Bai, Hualong; Lee, Jung Seok; Chen, Elizabeth; Wang, Mo; Xing, Ying; Fahmy, Tarek M.; Dardik, Alan

2017-01-01

Prosthetic grafts and patches are commonly used in cardiovascular surgery, however neointimal hyperplasia remains a significant concern, especially under low flow conditions. We hypothesized that delivery of rapamycin from nanoparticles (NP) covalently attached to patches allows sustained site-specific delivery of therapeutic agents targeted to inhibit localized neointimal hyperplasia. NP were covalently linked to pericardial patches using EDC/NHS chemistry and could deliver at least 360 ng rapamycin per patch without detectable rapamycin in serum; nanoparticles were detectable in the liver, kidney and spleen but no other sites within 24 hours. In a rat venous patch angioplasty model, control patches developed robust neointimal hyperplasia on the patch luminal surface characterized by Eph-B4-positive endothelium and underlying SMC and infiltrating cells such as macrophages and leukocytes. Patches delivering rapamycin developed less neointimal hyperplasia, less smooth muscle cell proliferation, and had fewer infiltrating cells but retained endothelialization. NP covalently linked to pericardial patches are a novel composite delivery system that allows sustained site-specific delivery of therapeutics; NP delivering rapamycin inhibit patch neointimal hyperplasia. NP linked to patches may represent a next generation of tissue engineered cardiovascular implants.

Space Radar Image of Moscow, Russia

NASA Image and Video Library

1999-05-01

This is a vertically polarized L-band image of the southern half of Moscow, an area which has been inhabited for 2,000 years. The image covers a diameter of approximately 50 kilometers (31 miles) and was taken on September 30, 1994 by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar aboard the space shuttle Endeavour. The city of Moscow was founded about 750 years ago and today is home to about 8 million residents. The southern half of the circular highway (a road that looks like a ring) can easily be identified as well as the roads and railways radiating out from the center of the city. The city was named after the Moskwa River and replaced Russia's former capital, St. Petersburg, after the Russian Revolution in 1917. The river winding through Moscow shows up in various gray shades. The circular structure of many city roads can easily be identified, although subway connections covering several hundred kilometers are not visible in this image. The white areas within the ring road and outside of it are buildings of the city itself and it suburban towns. Two of many airports are located in the west and southeast of Moscow, near the corners of the image. The Kremlin is located north just outside of the imaged city center. It was actually built in the 16th century, when Ivan III was czar, and is famous for its various churches. In the surrounding area, light gray indicates forests, while the dark patches are agricultural areas. The various shades from middle gray to dark gray indicate different stages of harvesting, ploughing and grassland. http://photojournal.jpl.nasa.gov/catalog/PIA01752

A Comparative Study of Intratesticular Ductules in the Spermatogenically Active Testes of Shortfin Mako and Thresher Sharks.

PubMed

McClusky, Leon Mendel; Sulikowski, James

2016-10-01

This comparative study of the radial testes of sexually mature thresher sharks (Alopias vulpinus) and shortfin mako sharks (Isurus oxyrinchus) describes the histology of the three-tiered network of sperm-carrying ductules in the testis and the lymphomyeloid tissue associated with it, namely the epigonal organ. In both species, a testis → epigonal gradient was evident regarding the thickness of the ductule epithelial lining and subepithelial investment of connective tissue. Ductules straddling the testis-epigonal border often displayed luminal leukocytes and various signs of regression, including the progressive thickening of the ductule epithelial lining, dissolution of the cytoplasm, and loss of normal histoarchitecture. In Isurus, large amorphous areas formed due to the fusion of neighboring regressing ductules. The epigonal organ of Alopias additionally revealed circular degenerative sperm-containing, Hassall-like bodies with either a degenerate or cellular appearance, the latter the result of cell proliferative activity (as shown by proliferating cell nuclear antigen (PCNA) immunohistochemistry) in an expanding outer border comprising cells with intensely PCNA immunoreactive slender and oblong nuclei. The latter cells exhibited a periphery-to-center transformation of their nuclei, at which stage they were PCNA-negative and most likely in a terminally differentiated state as they phagocytized the cell debris in the degenerate core. Intermediate stages of these circular bodies were a rarity. The relationship between these degenerate bodies, and the common occurrence of blind pockets in the epithelial linings and non-apoptosis-related degenerate patches in the apical cytoplasmic regions of the irregular shaped ductules in Alopias is unclear, and needs further elucidation. Anat Rec, 299:1435-1448, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Grassland Fire and Cattle Grazing Regulate Reptile and Amphibian Assembly Among Patches

NASA Astrophysics Data System (ADS)

Larson, Danelle M.

2014-12-01

Fire and grazing are common management schemes of grasslands globally and are potential drivers of reptilian and amphibian (herpetofauna) metacommunity dynamics. Few studies have assessed the impacts of fire and cattle grazing on herpetofauna assemblages in grasslands. A patch-burn grazing study at Osage Prairie, MO, USA in 2011-2012 created landscape patches with treatments of grazing, fire, and such legacies. Response variables were measured before and after the application of treatments, and I used robust-design occupancy modeling to estimate patch occupancy and detection rate within patches, and recolonization and extinction (i.e., dispersal) across patches. I conducted redundancy analysis and a permuted multivariate analysis of variance to determine if patch type and the associated environmental factors explained herpetofauna assemblage. Estimates for reptiles indicate that occupancy was seasonally constant in Control patches ( ψ ~ 0.5), but declined to ψ ~ 0.15 in patches following the applications of fire and grazing. Local extinctions for reptiles were higher in patches with fire or light grazing ( ɛ ~ 0.7) compared to the controls. For the riparian herpetofaunal community, patch type and grass height were important predictors of abundance; further, the turtles, lizards, snakes, and adult amphibians used different patch types. The aquatic amphibian community was predicted by watershed and in-stream characteristics, irrespective of fire or grazing. The varying responses from taxonomic groups demonstrate habitat partitioning across multiple patch types undergoing fire, cattle grazing, and legacy effects. Prairies will need an array of patch types to accommodate multiple herpetofauna species.

A hydrogel pericardial patch.

PubMed

Allder, M A; Guilbeau, E J; Brandon, T A; Walker, A S; Koeneman, J B; Fisk, R L

1990-01-01

Patients undergoing repeat cardiac operations are higher operative risks than those undergoing an initial cardiac procedure because adhesion formation can occur if the native pericardium is not closed. A unique composite patch that may be used to augment the pericardial tissue when primary closure is not possible has been developed. The patch is made of a hydrogel, poly (2-hydroxyethyl methacrylate), reinforced with an ethylene tetrafluoroethylene (ETFE) mesh. The mesh provides the needed mechanical properties, whereas the patch's surface properties are comparable to the hydrogel. Two types of patches were fabricated: one with the mesh weave at a perpendicular orientation and one at 45 degrees to the principle loading direction. The patches were mechanically tested and compared with canine pericardium. Ultimate tensile strength of the patches is not significantly different from canine pericardium (p less than 0.05), are the patch suture strength is nearly twice that of canine pericardium. The perpendicular patch is stiffer than canine pericardium, whereas the 45 degree patch is not (p less than 0.05). The 45 degree patch shows considerable promise as a pericardial substitute because it closely matches the properties native canine pericardium.

Selection of important ecological source patches base on Green Infrastructure theory: A case study of Wuhan city

NASA Astrophysics Data System (ADS)

Ke, Yuanyuan; Yu, Yan; Tong, Yan

2018-01-01

Selecting urban ecological patches is of great significance for constructing urban green infrastructure network, protecting urban biodiversity and ecological environment. With the support of GIS technology, a criterion for selecting sources of patches was developed according to existing planning. Then ecological source patches of terrestrial organism, aquatic and amphibious organism were selected in Wuhan city. To increase the connectivity of the ecological patches and achieve greater ecological protection benefits, the green infrastructure networks in Wuhan city were constructed with the minimum path analysis method. Finally, the characteristics of ecological source patches were analyzed with landscape metrics, and ecological protection importance degree of ecological source patches were evaluated comprehensively. The results showed that there were 23 important ecological source patches in Wuhan city, among which Sushan Temple Forest Patch, Lu Lake and Shangshe Lake Wetland Patch were the most important in all kinds of patches for ecological protection. This study can provide a scientific basis for the preservation of urban ecological space, the delineation of natural conservation areas and the protection of biological diversity.

The effects of patch shape and connectivity on nest site selection and reproductive success of the Indigo Bunting.

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

Weldon, Aimee Jean

2004-07-01

Description – Ph.D Dissertation. North Carolina State University. Raleigh, North Carolina. 135 pp. Abatract - Habitat fragmentation and its associated effects have been blamed for the recent population declines of many Neotropical migratory bird species. Increased predation and parasitism resulting from edge-related effects have been implicated for poor nesting success in many studies, mostly of forest interior species. However, little attention has been devoted to disturbance-dependent birds. In this study, I examine how patch shape and connectivity in fragmented landscapes affects the reproductive success of disturbance-dependent bird species, specifically the Indigo Bunting (Passerina cyanea). I conducted my study in amore » landscape-scale experimental system of similar-area habitat patches that differed in connectivity and in shape. Shapes differed between edgy and rectangular forms, where edgy patches contained 50% more edge than rectangular patches. I tested whether edgy patches function as ecological traps for species with strong edge preferences, by leading them to select dangerous habitats. Indigo Buntings preferentially selected edgy patches over rectangular patches, but experienced significantly lower reproductive success in edgy patches early in the season. Although predation pressure intensified in rectangular patches late in the season, seasonal fecundity was still significantly lower in edgy patches, providing the first empirical evidence that edges can function as ecological traps for Indigo Buntings. A second objective of my study was to evaluate the efficacy of conservation corridors for disturbance-dependent bird species. Conservation corridors have become a popular strategy to preserve biodiversity and promote gene flow in fragmented landscapes, but corridors may also have negative consequences. I tested the hypothesis that corridors can increase nest predation risk in connected patches relative to unconnected patches. Nest predation rates increased significantly in connected patches compared to unconnected rectangular patches, but were similar between connected patches and unconnected edgy patches. This suggests that the increase in predator activity in connected patches is largely attributable to edge effects incurred through the addition of a corridor. This is the first landscape-scale study to experimentally demonstrate the potential negative effects of conservation corridors.« less

Influence of habitat quality, population size, patch size, and connectivity on patch-occupancy dynamics of the middle spotted woodpecker.

PubMed

Robles, Hugo; Ciudad, Carlos

2012-04-01

Despite extensive research on the effects of habitat fragmentation, the ecological mechanisms underlying colonization and extinction processes are poorly known, but knowledge of these mechanisms is essential to understanding the distribution and persistence of populations in fragmented habitats. We examined these mechanisms through multiseason occupancy models that elucidated patch-occupancy dynamics of Middle Spotted Woodpeckers (Dendrocopos medius) in northwestern Spain. The number of occupied patches was relatively stable from 2000 to 2010 (15-24% of 101 patches occupied every year) because extinction was balanced by recolonization. Larger and higher quality patches (i.e., higher density of oaks >37 cm dbh [diameter at breast height]) were more likely to be occupied. Habitat quality (i.e., density of large oaks) explained more variation in patch colonization and extinction than did patch size and connectivity, which were both weakly associated with probabilities of turnover. Patches of higher quality were more likely to be colonized than patches of lower quality. Populations in high-quality patches were less likely to become extinct. In addition, extinction in a patch was strongly associated with local population size but not with patch size, which means the latter may not be a good surrogate of population size in assessments of extinction probability. Our results suggest that habitat quality may be a primary driver of patch-occupancy dynamics and may increase the accuracy of models of population survival. We encourage comparisons of competing models that assess occupancy, colonization, and extinction probabilities in a single analytical framework (e.g., dynamic occupancy models) so as to shed light on the association of habitat quality and patch geometry with colonization and extinction processes in different settings and species. ©2012 Society for Conservation Biology.

Large-scale experimental landscapes reveal distinctive effects of patch shape and connectivity on arthropod communities.

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

Orrock, John, L.; Curler, Gregory, R.; Danielson, Brent, J.

2011-09-14

The size, shape, and isolation of habitat patches can affect organism behavior and population dynamics, but little is known about the relative role of shape and connectivity in affecting ecological communities at large spatial scales. Using six sampling sessions from July 2001 until August 2002, we collected 33,685 arthropods throughout seven 12-ha experimental landscapes consisting of clear-cut patches surrounded by a matrix of mature pine forest. Patches were explicitly designed to manipulate connectivity (via habitat corridors) independently of area and edge effects. We found that patch shape, rather than connectivity, affected ground-dwelling arthropod richness and beta diversity (i.e. turnover ofmore » genera among patches). Arthropod communities contained fewer genera and exhibited less turnover in high-edge connected and high-edge unconnected patches relative to low-edge unconnected patches of similar area. Connectivity, rather than patch shape, affected the evenness of ground-dwelling arthropod communities; regardless of patch shape, high-edge connected patches had lower evenness than low- or high-edge unconnected patches. Among the most abundant arthropod orders, increased richness in low-edge unconnected patches was largely due to increased richness of Coleoptera, whereas Hymenoptera played an important role in the lower evenness in connected patches and patterns of turnover. These findings suggest that anthropogenic habitat alteration can have distinct effects on ground-dwelling arthropod communities that arise due to changes in shape and connectivity. Moreover, this work suggests that corridors, which are common conservation tools that change both patch shape and connectivity, can have multiple effects on arthropod communities via different mechanisms, and each effect may alter components of community structure.« less

Effects of Spatial Patch Arrangement and Scale of Covarying Resources on Growth and Intraspecific Competition of a Clonal Plant

PubMed Central

Wang, Yong-Jian; Shi, Xue-Ping; Meng, Xue-Feng; Wu, Xiao-Jing; Luo, Fang-Li; Yu, Fei-Hai

2016-01-01

Spatial heterogeneity in two co-variable resources such as light and water availability is common and can affect the growth of clonal plants. Several studies have tested effects of spatial heterogeneity in the supply of a single resource on competitive interactions of plants, but none has examined those of heterogeneous distribution of two co-variable resources. In a greenhouse experiment, we grew one (without intraspecific competition) or nine isolated ramets (with competition) of a rhizomatous herb Iris japonica under a homogeneous environment and four heterogeneous environments differing in patch arrangement (reciprocal and parallel patchiness of light and soil water) and patch scale (large and small patches of light and water). Intraspecific competition significantly decreased the growth of I. japonica, but at the whole container level there were no significant interaction effects of competition by spatial heterogeneity or significant effect of heterogeneity on competitive intensity. Irrespective of competition, the growth of I. japonica in the high and the low water patches did not differ significantly in the homogeneous treatments, but it was significantly larger in the high than in the low water patches in the heterogeneous treatments with large patches. For the heterogeneous treatments with small patches, the growth of I. japonica was significantly larger in the high than in the low water patches in the presence of competition, but such an effect was not significant in the absence of competition. Furthermore, patch arrangement and patch scale significantly affected competitive intensity at the patch level. Therefore, spatial heterogeneity in light and water supply can alter intraspecific competition at the patch level and such effects depend on patch arrangement and patch scale. PMID:27375630

Effects of Spatial Patch Arrangement and Scale of Covarying Resources on Growth and Intraspecific Competition of a Clonal Plant.

PubMed

Wang, Yong-Jian; Shi, Xue-Ping; Meng, Xue-Feng; Wu, Xiao-Jing; Luo, Fang-Li; Yu, Fei-Hai

2016-01-01

Spatial heterogeneity in two co-variable resources such as light and water availability is common and can affect the growth of clonal plants. Several studies have tested effects of spatial heterogeneity in the supply of a single resource on competitive interactions of plants, but none has examined those of heterogeneous distribution of two co-variable resources. In a greenhouse experiment, we grew one (without intraspecific competition) or nine isolated ramets (with competition) of a rhizomatous herb Iris japonica under a homogeneous environment and four heterogeneous environments differing in patch arrangement (reciprocal and parallel patchiness of light and soil water) and patch scale (large and small patches of light and water). Intraspecific competition significantly decreased the growth of I. japonica, but at the whole container level there were no significant interaction effects of competition by spatial heterogeneity or significant effect of heterogeneity on competitive intensity. Irrespective of competition, the growth of I. japonica in the high and the low water patches did not differ significantly in the homogeneous treatments, but it was significantly larger in the high than in the low water patches in the heterogeneous treatments with large patches. For the heterogeneous treatments with small patches, the growth of I. japonica was significantly larger in the high than in the low water patches in the presence of competition, but such an effect was not significant in the absence of competition. Furthermore, patch arrangement and patch scale significantly affected competitive intensity at the patch level. Therefore, spatial heterogeneity in light and water supply can alter intraspecific competition at the patch level and such effects depend on patch arrangement and patch scale.

How to measure cortical folding from MR images: a step-by-step tutorial to compute local gyrification index.

PubMed

Schaer, Marie; Cuadra, Meritxell Bach; Schmansky, Nick; Fischl, Bruce; Thiran, Jean-Philippe; Eliez, Stephan

2012-01-02

Cortical folding (gyrification) is determined during the first months of life, so that adverse events occurring during this period leave traces that will be identifiable at any age. As recently reviewed by Mangin and colleagues(2), several methods exist to quantify different characteristics of gyrification. For instance, sulcal morphometry can be used to measure shape descriptors such as the depth, length or indices of inter-hemispheric asymmetry(3). These geometrical properties have the advantage of being easy to interpret. However, sulcal morphometry tightly relies on the accurate identification of a given set of sulci and hence provides a fragmented description of gyrification. A more fine-grained quantification of gyrification can be achieved with curvature-based measurements, where smoothed absolute mean curvature is typically computed at thousands of points over the cortical surface(4). The curvature is however not straightforward to comprehend, as it remains unclear if there is any direct relationship between the curvedness and a biologically meaningful correlate such as cortical volume or surface. To address the diverse issues raised by the measurement of cortical folding, we previously developed an algorithm to quantify local gyrification with an exquisite spatial resolution and of simple interpretation. Our method is inspired of the Gyrification Index(5), a method originally used in comparative neuroanatomy to evaluate the cortical folding differences across species. In our implementation, which we name local Gyrification Index (lGI(1)), we measure the amount of cortex buried within the sulcal folds as compared with the amount of visible cortex in circular regions of interest. Given that the cortex grows primarily through radial expansion(6), our method was specifically designed to identify early defects of cortical development. In this article, we detail the computation of local Gyrification Index, which is now freely distributed as a part of the FreeSurfer Software (http://surfer.nmr.mgh.harvard.edu/, Martinos Center for Biomedical Imaging, Massachusetts General Hospital). FreeSurfer provides a set of automated reconstruction tools of the brain's cortical surface from structural MRI data. The cortical surface extracted in the native space of the images with sub-millimeter accuracy is then further used for the creation of an outer surface, which will serve as a basis for the lGI calculation. A circular region of interest is then delineated on the outer surface, and its corresponding region of interest on the cortical surface is identified using a matching algorithm as described in our validation study(1). This process is repeatedly iterated with largely overlapping regions of interest, resulting in cortical maps of gyrification for subsequent statistical comparisons (Fig. 1). Of note, another measurement of local gyrification with a similar inspiration was proposed by Toro and colleagues(7), where the folding index at each point is computed as the ratio of the cortical area contained in a sphere divided by the area of a disc with the same radius. The two implementations differ in that the one by Toro et al. is based on Euclidian distances and thus considers discontinuous patches of cortical area, whereas ours uses a strict geodesic algorithm and include only the continuous patch of cortical area opening at the brain surface in a circular region of interest.

PATCH image processor user's manual

NASA Technical Reports Server (NTRS)

Nieves, M. J. (Principal Investigator)

1980-01-01

The patch image processor extracts patches in various size (32 x 32, 64 x 64, 128 x 128, and 256 x 256 pixels) from full frame LANDSAT imagery data. With the patches that are extracted, a patch image mosaic is created in the image processing system, IMDACS, format.

Resource concentration hypothesis: effect of host plant patch size on density of herbivorous insects.

PubMed

Grez, A A; González, R H

1995-09-01

The resource concentration hypothesis (Root 1973) predicts that specialist herbivorous insects should be more abundant in large patches of host plants, because the insects are more likely to find and stay longer in those patches. Between August 1989 and January 1990 we experimentally tested Root's hypothesis by analyzing the numerical response of four species of herbivorous insects associated with patches of 4, 16, 64 and 225 cabbage plants, Brassica oleracea var. capitata. In addition, we studied the colonization of patches by adults of Plutella xylostella (L.) (Lepidoptera: Plutellidae), and the migration of their larvae in patches of different sizes. No herbivorous insect densities differed significantly with patch size. Adults of P. xylostella colonized all kind of patches equally. Larvae did not migrate between patches, and their disappearance rate did not differ between patches. The resource concentration hypothesis is organism-dependent, being a function of the adult and juvenile herbivore dispersal behavior in relation to the spatial scale of patchiness.

Patch Finder Plus (PFplus): a web server for extracting and displaying positive electrostatic patches on protein surfaces.

PubMed

Shazman, Shula; Celniker, Gershon; Haber, Omer; Glaser, Fabian; Mandel-Gutfreund, Yael

2007-07-01

Positively charged electrostatic patches on protein surfaces are usually indicative of nucleic acid binding interfaces. Interestingly, many proteins which are not involved in nucleic acid binding possess large positive patches on their surface as well. In some cases, the positive patches on the protein are related to other functional properties of the protein family. PatchFinderPlus (PFplus) http://pfp.technion.ac.il is a web-based tool for extracting and displaying continuous electrostatic positive patches on protein surfaces. The input required for PFplus is either a four letter PDB code or a protein coordinate file in PDB format, provided by the user. PFplus computes the continuum electrostatics potential and extracts the largest positive patch for each protein chain in the PDB file. The server provides an output file in PDB format including a list of the patch residues. In addition, the largest positive patch is displayed on the server by a graphical viewer (Jmol), using a simple color coding.

Patch Finder Plus (PFplus): A web server for extracting and displaying positive electrostatic patches on protein surfaces

PubMed Central

Shazman, Shula; Celniker, Gershon; Haber, Omer; Glaser, Fabian; Mandel-Gutfreund, Yael

2007-01-01

Positively charged electrostatic patches on protein surfaces are usually indicative of nucleic acid binding interfaces. Interestingly, many proteins which are not involved in nucleic acid binding possess large positive patches on their surface as well. In some cases, the positive patches on the protein are related to other functional properties of the protein family. PatchFinderPlus (PFplus) http://pfp.technion.ac.il is a web-based tool for extracting and displaying continuous electrostatic positive patches on protein surfaces. The input required for PFplus is either a four letter PDB code or a protein coordinate file in PDB format, provided by the user. PFplus computes the continuum electrostatics potential and extracts the largest positive patch for each protein chain in the PDB file. The server provides an output file in PDB format including a list of the patch residues. In addition, the largest positive patch is displayed on the server by a graphical viewer (Jmol), using a simple color coding. PMID:17537808

[Preoperative and follow-up cardiac magnetic resonance imaging of candidates for surgical ventricular restoration].

PubMed

Rodríguez Masi, M; Martín Lores, I; Bustos García de Castro, A; Cabeza Martínez, B; Maroto Castellanos, L; Gómez de Diego, J; Ferreirós Domínguez, J

2016-01-01

To assess pre and post-operative cardiac MRI (CMR) findings in patients with left endoventriculoplasty repair for ventricular aneurysm due to ischemic heart disease. Data were retrospectively gathered on 21 patients with diagnosis of ventricular aneurysm secondary to ischemic heart disease undergoing left endoventriculoplasty repair between January 2007 and March 2013. Pre and post-operative CMR was performed in 12 patients. The following data were evaluated in pre-operative and post-operative CMR studies: quantitative analysis of left ventricular ejection fraction (LVEF), left ventricular end-diastolic (LVEDV) and end-systolic (LVESV) volume index, presence of valvular disease and intracardiac thrombi. The time between surgery and post-operative CRM studies was 3-24 months. Significant differences were found in the pre and post-operative LVEF, LVEDV and LVESV data. EF showed a median increase of 10% (IQR 2-15) (p=0.003). The LVEDV showed a median decrease of 38 ml/m(2) (IQR 18-52) (p=0.006) and the LVESV showed a median decrease of 45 ml/m(2) (IQR:12-60) (p=0.008). Post-operative ventricular volume reduction was significantly higher in those patients with preoperative LVESV >110 ml/m(2) (59 ml/m(2) and 12 ml/m(2), p=0.006). In patients with ischemic heart disease that are candidates for left endoventriculoplasty, CMR is a reliable non-invasive and reproducible technique for the evaluation of the scar before the surgery and the ventricular volumes and its evolution after endoventricular surgical repair. Copyright © 2014 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

Periodic creation of polar cap patches from auroral transients in the cusp

NASA Astrophysics Data System (ADS)

Hosokawa, K.; Taguchi, S.; Ogawa, Y.

2016-06-01

On 24 November 2012, an interval of polar cap patches was identified by an all-sky airglow imager located near the dayside cusp. During the interval, the successive appearance of poleward moving auroral forms (PMAFs) was detected, which are known to represent ionospheric manifestations of pulsed magnetic reconnections at the dayside magnetopause. All of the patches observed during the interval appeared from these transient auroral features (i.e., there was a one-to-one correspondence between PMAFs and newly created baby patches). This fact strongly suggests that patches can be directly and seamlessly created from a series of PMAFs. The optical intensities of the baby patches were 100-150 R, which is slightly lower than typical patch luminosity on the nightside and may imply that PMAF-induced patches are generally low density. The generation of such patches could be explained by impact ionization due to soft particle precipitation into PMAFs traces. In spite of the faint signature of the baby patches, two coherent HF radars of the SuperDARN network observed backscatter echoes in the central polar cap, which represented signatures of plasma irregularities associated with the baby patches. These indicate that patches created from PMAFs have the potential to affect the satellite communications environment in the central polar cap region.

Rapid establishment of a regular distribution of adult tropical Drosophila parasitoids in a multi-patch environment by patch defence behaviour.

PubMed

de Jong, Peter W; Hemerik, Lia; Gort, Gerrit; van Alphen, Jacques J M

2011-01-01

Females of the larval parasitoid of Drosophila, Asobara citri, from sub-Saharan Africa, defend patches with hosts by fighting and chasing conspecific females upon encounter. Females of the closely related, palearctic species Asobara tabida do not defend patches and often search simultaneously in the same patch. The effect of patch defence by A. citri females on their distribution in a multi-patch environment was investigated, and their distributions were compared with those of A. tabida. For both species 20 females were released from two release-points in replicate experiments. Females of A. citri quickly reached a regular distribution across 16 patches, with a small variance/mean ratio per patch. Conversely, A. tabida females initially showed a clumped distribution, and after gradual dispersion, a more Poisson-like distribution across patches resulted (variance/mean ratio was closer to 1 and higher than for A. citri). The dispersion of A. tabida was most probably an effect of exploitation: these parasitoids increasingly made shorter visits to already exploited patches. We briefly discuss hypotheses on the adaptive significance of patch defence behaviour or its absence in the light of differences in the natural history of both parasitoid species, notably the spatial distribution of their hosts.

Effect of patch borders on coercivity in amorphous rare earth-transition metal thin films

NASA Technical Reports Server (NTRS)

Patterson, G.; Fu, H.; Giles, R. C.; Mansuripur, M.

1991-01-01

The coercivity at the micron scale is a very important property of magneto-optical media. It is a key factor that determines the magnetic domain wall movement and domain reversal. How the coercivity is influenced by a special type of patch borders is discussed. Patch formation is a general phenomenon in growth processes of amorphous rare earth transition metal thin films. Different patches may stem from different seeds and the patch borders are formed when they merge. Though little is known about the exact properties of the borders, we may expect that the exchange interaction at the patch border is weaker than that within a patch, since there is usually a spatial gap between two patches. Computer simulations were performed on a 2-D hexagonal lattice consisting of 37 complete patches with random shape and size. From the series of simulations we may conclude that the domain in the patch with borders of 30 percent exchange strength can expand most easily to the whole lattice, because the exchange strength can expand most easily to the whole lattice, because the exchange strength of the border is not too high to prevent the domain from growing within the patch and it is not too low to prevent the domain from expanding beyond the patch.

Departure Mechanisms for Host Search on High-Density Patches by the Meteorus pulchricornis

PubMed Central

Sheng, Sheng; Feng, Sufang; Meng, Ling; Li, Baoping

2014-01-01

Abstract Less attention has been paid to the parasitoid–host system in which the host occurs in considerably high density with a hierarchical patch structure in studies on time allocation strategies of parasitoids. This study used the parasitoid Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae) and the Oriental leafworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) as the parasitoids–host model system to investigate patch-leaving mechanisms as affected by the high-host density, hierarchical patch structure, and foraging behaviors on both former and current patches. The results showed that three out of eight covariates tested had significant effects on the patch-leaving tendency, including the host density, ovipositor insertion, and host rejection on the current patch. The parasitoid paid more visits to the patch with high-density hosts. While the patch with higher host densities decreased the leaving tendency, the spatial distribution of hosts examined had no effect on the leaving tendency. Both oviposition and host rejection decreased the patch-leaving tendency. The variables associated with the former patch, such as the host density and number of ovipositor insertions, however, did not have an effect on the leaving tendency. Our study suggested that M. pulchricornis females may use an incremental mechanism to exploit high-density patches to the fullest. PMID:25502040

Nevirapine patch testing in Thai human immunodeficiency virus infected patients with nevirapine drug hypersensitivity.

PubMed

Prasertvit, Piyatida; Chareonyingwattana, Angkana; Wattanakrai, Penpun

2017-12-01

Antiretroviral drug hypersensitivity in HIV patients is common. Publications have shown that Abacavir (ABC) patch testing is useful in confirming ABC hypersensitivity in 24-50% of cases with a 100% sensitivity of HLA-B*5701 in patch test positive cases. However, Nevirapine (NVP) patch testing has not been reported. (1) To evaluate the usefulness and safety of NVP patch testing in Thai HIV patients with NVP hypersensitivity. (2) To assess the correlation of positive patch tests with HLA-B*3505. Patients were classified into two groups: (1) study group of 20 HIV NVP hypersensitivity patients and (2) control group of 15 volunteers without NVP hypersensitivity. Both groups were patch tested with purified and commercialized form of NVP in various vehicles. Two HIV patients with NVP hypersensitivity were patch test positive. All controls tested negative. Three HIV patients were positive for HLA-B*3505 and the two patients with positive patch testing were both HLA-B*3505 positive. NVP patch testing in Thai HIV patients is safe and can be used to help confirm the association between NVP and hypersensitivity skin reactions. NVP patch test results significantly correlated with HLA-B*3505. The sensitivity of HLA-B*3505 for positive patch test was 100%. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Age-related changes in the anatomical characteristics of Peyer's patches in small intestine of Bactrian camels (Camelus bactrianus).

PubMed

Qi, Shan-Shan; Wang, Wen-Hui; Gao, Qiang; Xu, Xiao-Hong; He, Wan-Hong; Zhaxi, Ying-Pai; Tai, Li-Feng

2011-08-01

The distribution, size, and appearance of Peyer's patches vary according to species. In order to determine the anatomical characteristics of Peyer's patches in small intestine of Bactrian camel, and age-related changes in the number of Peyer's patches, 40 Bactrian camels of the following four age groups were studied: young (0.5-2 years), pubertal (3-5 years), middle-aged (6-16 years), and old (17-20 years). The exact number of Peyer's patches was recorded, and the appearance of Peyer's patches was described in detail. The results indicated that Peyer's patches of Bactrian camels not only have a particular anatomical location and distinct appearance but also change with age. They were distributed in the whole small intestine and there were four distinct types of Peyer's patches: nodular, faviform, cup-shaped, and cystic form Peyer's patches. However, the nodular and cystic form Peyer's patches are specific to Bactrian camel, which have not been found in other animals including Dromedary camel. In addition, the distribution density of Peyer's patches in ileum was the maximum, then was jejunum and duodenum. Further statistical analysis showed that the number of Peyer's patches was altered with age. The number peaked in 5-year-old camels and declined subsequently with age. However, there was little change in the size of Peyer's patches in different age groups; no age-related macroscopic variations in the shape or size of the Peyer's patches were found. Results obtained from this study provide the basic information to further study on the gastrointestinal mucosal immunity of Bactrian camel.

Closure technique after carotid endarterectomy influences local hemodynamics.

PubMed

Harrison, Gareth J; How, Thien V; Poole, Robert J; Brennan, John A; Naik, Jagjeeth B; Vallabhaneni, S Rao; Fisher, Robert K

2014-08-01

Meta-analysis supports patch angioplasty after carotid endarterectomy (CEA); however, studies indicate considerable variation in practice. The hemodynamic effect of a patch is unclear and this study attempted to elucidate this and guide patch width selection. Four groups were selected: healthy volunteers and patients undergoing CEA with primary closure, trimmed patch (5 mm), or 8-mm patch angioplasty. Computer-generated three-dimensional models of carotid bifurcations were produced from transverse ultrasound images recorded at 1-mm intervals. Rapid prototyping generated models for flow visualization studies. Computational fluid dynamic studies were performed for each model and validated by flow visualization. Mean wall shear stress (WSS) and oscillatory shear index (OSI) maps were created for each model using pulsatile inflow at 300 mL/min. WSS of <0.4 Pa and OSI >0.3 were considered pathological, predisposing to accretion of intimal hyperplasia. The resultant WSS and OSI maps were compared. The four groups comprised 8 normal carotid arteries, 6 primary closures, 6 trimmed patches, and seven 8-mm patches. Flow visualization identified flow separation and recirculation at the bifurcation increased with a patch and was related to the patch width. Computational fluid dynamic identified that primary closure had the fewest areas of low WSS or elevated OSI but did have mild common carotid artery stenoses at the proximal arteriotomy that caused turbulence. Trimmed patches had more regions of abnormal WSS and OSI at the bifurcation, but 8-mm patches had the largest areas of deleteriously low WSS and high OSI. Qualitative comparison among the four groups confirmed that incorporation of a patch increased areas of low WSS and high OSI at the bifurcation and that this was related to patch width. Closure technique after CEA influences the hemodynamic profile. Patching does not appear to generate favorable flow dynamics. However, a trimmed 5-mm patch may offer hemodynamic benefits over an 8-mm patch and may be the preferred option. Copyright © 2014 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Integrated Antenna/Solar Array Cell (IA/SAC) System for Flexible Access Communications

NASA Technical Reports Server (NTRS)

Lee, Ricard Q.; Clark, Eric B.; Pal, Anna Maria T.; Wilt, David M.; Mueller, Carl H.

2004-01-01

Present satellite communications systems normally use separate solar cells and antennas. Since solar cells generally account for the largest surface area of the spacecraft, co-locating the antenna and solar cells on the same substrate opens the possibility for a number of data-rate-enhancing communications link architecture that would have minimal impact on spacecraft weight and size. The idea of integrating printed planar antenna and solar array cells on the same surface has been reported in the literature. The early work merely attempted to demonstrate the feasibility by placing commercial solar cells besides a patch antenna. Recently, Integrating multiple antenna elements and solar cell arrays on the same surface was reported for both space and terrestrial applications. The application of photovoltaic solar cell in a planar antenna structure where the radiating patch antenna is replaced by a Si solar cell has been demonstrated in wireless communication systems (C. Bendel, J. Kirchhof and N. Henze, 3rd Would Photovotaic Congress, Osaka, Japan, May 2003). Based on a hybrid approach, a 6x1 slot array with circularly polarized crossdipole elements co-located on the same surface of the solar cells array has been demonstrated (S. Vaccaro, J. R. Mosig and P. de Maagt, IEEE Trans. Ant. and Propag., Vol. 5 1, No. 8, Aug. 2003). Amorphous silicon solar cells with about 5-10% efficiency were used in these demonstrations. This paper describes recent effort to integrate advanced solar cells with printed planar antennas. Compared to prior art, the proposed WSAC concept is unique in the following ways: 1) Active antenna element will be used to achieve dynamic beam steering; 2) High efficiency (30%) GaAs multi-junction solar cells will be used instead of Si, which has an efficiency of about 15%; 3) Antenna and solar cells are integrated on a common GaAs substrate; and 4) Higher data rate capability. The IA/SAC is designed to operate at X-band (8-12 GH) and higher frequencies Higher operating frequencies enable greater bandwidth and thus higher data transfer rates. The first phase of the effort involves the development of GaAs solar cell MIMs (Monolithically Integrated Module) with a single patch antenna on the opposite side of the substrate. Subsequent work will involve the integration of MIMs and antennas on the same side of the substrate. Results from the phase one efforts will be presented.

Precision of systematic and random sampling in clustered populations: habitat patches and aggregating organisms.

PubMed

McGarvey, Richard; Burch, Paul; Matthews, Janet M

2016-01-01

Natural populations of plants and animals spatially cluster because (1) suitable habitat is patchy, and (2) within suitable habitat, individuals aggregate further into clusters of higher density. We compare the precision of random and systematic field sampling survey designs under these two processes of species clustering. Second, we evaluate the performance of 13 estimators for the variance of the sample mean from a systematic survey. Replicated simulated surveys, as counts from 100 transects, allocated either randomly or systematically within the study region, were used to estimate population density in six spatial point populations including habitat patches and Matérn circular clustered aggregations of organisms, together and in combination. The standard one-start aligned systematic survey design, a uniform 10 x 10 grid of transects, was much more precise. Variances of the 10 000 replicated systematic survey mean densities were one-third to one-fifth of those from randomly allocated transects, implying transect sample sizes giving equivalent precision by random survey would need to be three to five times larger. Organisms being restricted to patches of habitat was alone sufficient to yield this precision advantage for the systematic design. But this improved precision for systematic sampling in clustered populations is underestimated by standard variance estimators used to compute confidence intervals. True variance for the survey sample mean was computed from the variance of 10 000 simulated survey mean estimates. Testing 10 published and three newly proposed variance estimators, the two variance estimators (v) that corrected for inter-transect correlation (ν₈ and ν(W)) were the most accurate and also the most precise in clustered populations. These greatly outperformed the two "post-stratification" variance estimators (ν₂ and ν₃) that are now more commonly applied in systematic surveys. Similar variance estimator performance rankings were found with a second differently generated set of spatial point populations, ν₈ and ν(W) again being the best performers in the longer-range autocorrelated populations. However, no systematic variance estimators tested were free from bias. On balance, systematic designs bring more narrow confidence intervals in clustered populations, while random designs permit unbiased estimates of (often wider) confidence interval. The search continues for better estimators of sampling variance for the systematic survey mean.

Single-layer dual frequency patch antenna

NASA Astrophysics Data System (ADS)

Maci, S.; Gentili, G. B.; Avitabile, G.

1993-08-01

A configuration for a slotted patch antenna is introduced which allows two separate operating frequencies. Both of these frequencies are associated with a radiating mode almost identical to that of a standard patch. The two resonances are related to the patch width and the slot/patch length, respectively.

Energy analysis in the elliptic restricted three-body problem

NASA Astrophysics Data System (ADS)

Qi, Yi; de Ruiter, Anton

2018-07-01

The gravity assist or flyby is investigated by analysing the inertial energy of a test particle in the elliptic restricted three-body problem (ERTBP), where two primary bodies are moving in elliptic orbits. First, the expression of the derivation of energy is obtained and discussed. Then, the approximate expressions of energy change in a circular neighbourhood of the smaller primary are derived. Numerical computation indicates that the obtained expressions can be applied to study the flyby problem of the nine planets and the Moon in the Solar system. Parameters related to the flyby are discussed analytically and numerically. The optimal conditions, including the position and time of the periapsis, for a flyby orbit are found to make a maximum energy gain or loss. Finally, the mechanical process of a flyby orbit is uncovered by an approximate expression in the ERTBP. Numerical computations testify that our analytical results well approximate the mechanical process of flyby orbits obtained by the numerical simulation in the ERTBP. Compared with the previous research established in the patched-conic method and numerical calculation, our analytical investigations based on a more elaborate derivation get more original results.

Triton - False Color of Cantaloupe Terrain

NASA Image and Video Library

1996-09-26

Voyager violet, green, and ultraviolet images of Triton were map projected into cylindrical coordinates and combined to produce this false color terrain map. Several compositionally distinct terrain and geologic features are portrayed. At center is a gray blue unit referred to as 'cantaloupe' terrain because of its unusual topographic texture. The unit appears to predate other units to the left. Immediately adjacent to the cantaloupe terrain, is a smoother unit, represented by a reddish color, that has been dissected by a prominent fault system. This unit apparently overlies a much higher albedo material, seen farther left. A prominent angular albedo boundary separates relatively undisturbed smooth terrain from irregular patches which have been derived from breakup of the same material. Also visible at the far left are diffuse, elongated streaks, which seem to emanate from circular, often bright centered features. The parallel streaks may represent vented particulate materials blown in the same direction by winds in Triton's thin atmosphere. The Voyager Mission was conducted by JPL for NASA's Office of Space Science and Applications. http://photojournal.jpl.nasa.gov/catalog/PIA00060

A Computational Model of Afterimage Rotation in the Peripheral Drift Illusion Based on Retinal ON/OFF Responses

PubMed Central

Hayashi, Yuichiro; Ishii, Shin; Urakubo, Hidetoshi

2014-01-01

Human observers perceive illusory rotations after the disappearance of circularly repeating patches containing dark-to-light luminance. This afterimage rotation is a very powerful phenomenon, but little is known about the mechanisms underlying it. Here, we use a computational model to show that the afterimage rotation can be explained by a combination of fast light adaptation and the physiological architecture of the early visual system, consisting of ON- and OFF-type visual pathways. In this retinal ON/OFF model, the afterimage rotation appeared as a rotation of focus lines of retinal ON/OFF responses. Focus lines rotated clockwise on a light background, but counterclockwise on a dark background. These findings were consistent with the results of psychophysical experiments, which were also performed by us. Additionally, the velocity of the afterimage rotation was comparable with that observed in our psychophysical experiments. These results suggest that the early visual system (including the retina) is responsible for the generation of the afterimage rotation, and that this illusory rotation may be systematically misinterpreted by our high-level visual system. PMID:25517906

Energy Analysis in the Elliptic Restricted Three-body Problem

NASA Astrophysics Data System (ADS)

Qi, Yi; de Ruiter, Anton

2018-05-01

The gravity assist or flyby is investigated by analyzing the inertial energy of a test particle in the elliptic restricted three-body problem (ERTBP), where two primary bodies are moving in elliptic orbits. Firstly, the expression of the derivation of energy is obtained and discussed. Then, the approximate expressions of energy change in a circular neighborhood of the smaller primary are derived. Numerical computation indicates that the obtained expressions can be applied to study the flyby problem of the nine planets and the Moon in the solar system. Parameters related to the flyby are discussed analytically and numerically. The optimal conditions, including the position and time of the periapsis, for a flyby orbit are found to make a maximum energy gain or loss. Finally, the mechanical process of a flyby orbit is uncovered by an approximate expression in the ERTBP. Numerical computations testify that our analytical results well approximate the mechanical process of flyby orbits obtained by the numerical simulation in the ERTBP. Compared with the previous research established in the patched-conic method and numerical calculation, our analytical investigations based on a more elaborate derivation get more original results.

Efficient technical solution for recycling textile materials by manufacturing nonwoven geotextiles

NASA Astrophysics Data System (ADS)

Leon, A. L.; Potop, G. L.; Hristian, L.; Manea, L. R.

2016-08-01

This paper aims to support the concept "circular economy" that was developed recently. It presents an efficient method for creating a closed loop in the Romanian textile industry by recycling textile materials, such as polyacrylonitrile knitted old products (collected from population) and small polyester woven patches from pre-consumer waste (garments manufacturing companies). Because of their properties, nonwoven geotextiles have many advantages in railways reinforcement, slopes stabilization, erosion control, drainage, filtration, paving roads, crops coverings, etc. The nonwoven geotextiles were obtained from three fibrous blends based on recovered fibers (PES and PAN) and fibers at first usage (PP) in different ratios. All experimental variants were processed on the same manufacturing line with the same technological parameters. There were tested the main physical and mechanical parameters and it was applied single factor ANOVA method for thickness, bulk density, air permeability and static puncture strength. The conclusion is that adding PP fibers in the blends represents a very important factor for geotextiles characteristics but it possible to decrease the ratio from economical reasons and still maintain a high quality level of nonwovens.

Effect of ocular transverse chromatic aberration on detection acuity for peripheral vision.

PubMed

Cheney, Frank; Thibos, Larry; Bradley, Arthur

2015-01-01

We examined the effect of transverse chromatic aberration (TCA) on detection acuity for white-light interference fringes seen in Maxwellian view at various orientations and locations in the visual field. A circular patch (3.5° diameter, 3.2 log Trolands) of nominally high-contrast fringes was produced on the retina by a commercial instrument (the Lotmar Visometer, Haag Streit) mounted on a gimbal for controlled positioning of the stimulus in the visual field from 0° to 35° eccentricity. Detection acuity for white light fringes for all meridians and eccentricities ≥15° was maximum when fringes were oriented parallel to the visual meridian line. This meridional effect disappeared when a narrow-band filter was used to eliminate TCA. The meridional effect also disappeared when the interferometric stimulator was displaced laterally to align the instrument with the eye's local achromatic axis. Modelling confirmed that TCA is the major factor responsible for white-light meridional bias, with minor contribution arising from higher-order monochromatic aberrations and neural factors. © 2014 The Authors Ophthalmic & Physiological Optics © 2014 The College of Optometrists.

Precision of synesthetic color matching resembles that for recollected colors rather than physical colors.

PubMed

Arnold, Derek H; Wegener, Signy V; Brown, Francesca; Mattingley, Jason B

2012-10-01

Grapheme-color synesthesia is an atypical condition in which individuals experience sensations of color when reading printed graphemes such as letters and digits. For some grapheme-color synesthetes, seeing a printed grapheme triggers a sensation of color, but hearing the name of a grapheme does not. This dissociation allowed us to compare the precision with which synesthetes are able to match their color experiences triggered by visible graphemes, with the precision of their matches for recalled colors based on the same graphemes spoken aloud. In six synesthetes, color matching for printed graphemes was equally variable relative to recalled experiences. In a control experiment, synesthetes and age-matched controls either matched the color of a circular patch while it was visible on a screen, or they judged its color from memory after it had disappeared. Both synesthetes and controls were more variable when matching from memory, and the variance of synesthetes' recalled color judgments matched that associated with their synesthetic judgments for visible graphemes in the first experiment. Results suggest that synesthetic experiences of color triggered by achromatic graphemes are analogous to recollections of color.

Formation of charge-nanopatterned templates with flexible geometry via layer by layer deposition of polyelectrolytes for directed self-assembly of gold nanoparticles

NASA Astrophysics Data System (ADS)

Sayin, Mustafa; Dahint, Reiner

2017-03-01

Nanostructure formation via self-assembly processes offers a fast and cost-effective approach to generate surface patterns on large lateral scale. In particular, if the high precision of lithographic techniques is not required, a situation typical of many biotechnological and biomedical applications, it may be considered as the method of choice as it does not require any sophisticated instrumentation. However, in many cases the variety and complexity of the surface structures accessible with a single self-assembly based technique is limited. Here, we report on a new approach which combines two different self-assembly strategies, colloidal lithography and layer-by-layer deposition of polyelectrolytes, in order to significantly expand the spectrum of accessible patterns. In particular, flat and donut-like charge-patterned templates have been generated, which facilitate subsequent deposition of gold nanoparticles in dot, grid, ring, out-of-ring and circular patch structures. Potential applications are e.g. in the fields of biofunctional interfaces with well-defined lateral dimensions, optical devices with tuned properties, and controlled three-dimensional material growth.

Dual band monopole antenna for WLAN 2.4/5.2/5.8 with truncated ground

NASA Astrophysics Data System (ADS)

Chandan, Bharti, Gagandeep; Srivastava, Toolika; Rai, B. S.

2018-04-01

A dual-band mono-pole antenna is proposed for Wireless LAN applications. The WLAN band is obtained by cutting a rectangular ring and a circular slot in the radiating patch. The overall dimension of antenna is 17×16.5×0.8 mmł. The frequency bands obtained are 2.38-2.9 GHz and 4.7-6.1 GHz with ≤ - 10 dB return loss which covers WLAN 2.4/5.2/5.8 GHz bands. The behavior of the antenna is analyzed in terms of radiation pattern, peak realized gain, radiation efficiency and surface current density. It has dipole like radiation pattern with gain of 2.33 - 4.31 dBi for lower frequency band and 4.29 - 5.16 dBi for upper frequency band with radiation efficiency of 95-98% and 93-96% respectively. The parametric analysis is carried out to understand the consequence of the various shape parameters and to get an optimum design. The simulation and measurement gave the results having close agreement.

A study of tensile residual strength of composite laminates under different patch-repaired series

NASA Astrophysics Data System (ADS)

Ding, M. H.; zhan, S.; Tang, Y. H.; Wang, L.; Ma, D. Q.; Wang, R. G.

2017-09-01

The tensile behavior of composite laminate structures repaired by bonding external patches was studied in the paper. Two different types of patches including wedge patches and inverted wedge patches were used and failure mechanisms, failure load and strength predictions were studied. A convenient and fast method of building 2-D finite element modeling (FEM) of laminate structure repaired was proposed and the strength of repaired laminate structures was calculated by FEM. The results showed that more than 80% tensile strength of the undamaged laminate could be recovered by bonding patch repairs. Moreover, the results indicated that the strength of inverted wedge patches repair were higher than that of wedge patches repair. FEM simulation results indicated that high stress concentration was found along the edges of invert patches and the most weakness part located in the adhesive bondline. FEM analysis results showed that the strength predicted matched well with the test strength.

GIS-based approach for quantifying landscape connectivity of Javan Hawk-Eagle habitat

NASA Astrophysics Data System (ADS)

Nurfatimah, C.; Syartinilia; Mulyani, Y. A.

2018-05-01

Javan Hawk-Eagle (Nisaetus bartelsi; JHE) is a law-protected endemic raptor which currently faced the decreased in number and size of habitat patches that will lead to patch isolation and species extinction. This study assessed the degree of connectivity between remnant habitat patches in central part of Java by utilizing Conefor Sensinode software as an additional tool for ArcGIS. The connectivity index was determined by three fractions which are infra, flux and connector. Using connectivity indices successfully identified 4 patches as core habitat, 9 patches as stepping-stone habitat and 6 patches as isolated habitat were derived from those connectivity indices. Those patches then being validated with land cover map derived from Landsat 8 of August 2014. 36% of core habitat covered by natural forest, meanwhile stepping stone habitat has 55% natural forest and isolated habitat covered by 59% natural forest. Isolated patches were caused by zero connectivity (PCcon = 0) and the patch size which too small to support viable JHE population. Yet, the condition of natural forest and the surrounding matrix landscape in isolated patches actually support the habitat need. Thus, it is very important to conduct the right conservation management system based on the condition of each patches.

The art and science of mission patches and their origins in society

NASA Astrophysics Data System (ADS)

Brumfitt, A.; Thompson, L. A.; Raitt, D.

2008-06-01

Space exploration utilizes some of the latest and highest technology available to human kind; synonymous with space exploration is the mission patch. This specialized art form popularizes the exploration of space with millions of mission patches sold around the world. Space tourism and education centres like the Kennedy Space Centre rely heavily on each space shuttle launch to support their merchandising of mission patches, from the traditional sew on badge to T shirts. Do mission patches tell a story? Are they Art? What is the origin and role of this art form in society? The art form of space mission patches combines the 21st century relevance with heraldic origins predating the ninth century. The space mission patch is designed by the astronauts themselves if it is a manned mission. As an education tool teachers and educators use the space mission patch to engage their students in the excitement of space exploration, the mission patch design is utilized as an education tool in literature, science and art. The space mission patch is a particularly powerful message medium. This paper looks at the origins of the space mission patch, its relevance to art and its impact on society.

Invertebrate community response to a shifting mosaic of habitat

USGS Publications Warehouse

Engle, David M.; Fuhlendorf, S.D.; Roper, A.; Leslie, David M.

2008-01-01

Grazing management has focused largely on promoting vegetation homogeneity through uniform distribution of grazing to minimize area in a pasture that is either heavily disturbed or undisturbed. An alternative management model that couples grazing and fire (i.e., patch burning) to promote heterogeneity argues that grazing and fire interact through a series of positive and negative feedbacks to cause a shifting mosaic of vegetation composition and structure across the landscape. We compared patch burning with traditional homogeneity-based management in tallgrass prairie to determine the influence of the two treatments on the aboveground invertebrate community. Patch burning resulted in a temporal flush of invertebrate biomass in patches transitional between unburned and patches burned in the current year. Total invertebrate mass was about 50% greater in these transitional patches within patch-burned pastures as compared to pastures under traditional, homogeneity-based management. Moreover, the mosaic of patches in patch-burned pastures contained a wider range of invertebrate biomass and greater abundance of some invertebrate orders than did the traditionally managed pastures. Patch burning provides habitat that meets requirements for a broad range of invertebrate species, suggesting the potential for patch burning to benefit other native animal assemblages in the food chain.

The effect of travel loss on evolutionarily stable distributions of populations in space.

PubMed

Deangelis, Donald L; Wolkowicz, Gail S K; Lou, Yuan; Jiang, Yuexin; Novak, Mark; Svanbäck, Richard; Araújo, Márcio S; Jo, Youngseung; Cleary, Erin A

2011-07-01

A key assumption of the ideal free distribution (IFD) is that there are no costs in moving between habitat patches. However, because many populations exhibit more or less continuous population movement between patches and traveling cost is a frequent factor, it is important to determine the effects of costs on expected population movement patterns and spatial distributions. We consider a food chain (tritrophic or bitrophic) in which one species moves between patches, with energy cost or mortality risk in movement. In the two-patch case, assuming forced movement in one direction, an evolutionarily stable strategy requires bidirectional movement, even if costs during movement are high. In the N-patch case, assuming that at least one patch is linked bidirectionally to all other patches, optimal movement rates can lead to source-sink dynamics where patches with negative growth rates are maintained by other patches with positive growth rates. As well, dispersal between patches is not balanced (even in the two-patch case), leading to a deviation from the IFD. Our results indicate that cost-associated forced movement can have important consequences for spatial metapopulation dynamics. Relevance to marine reserve design and the study of stream communities subject to drift is discussed.

PL-PatchSurfer: a novel molecular local surface-based method for exploring protein-ligand interactions.

PubMed

Hu, Bingjie; Zhu, Xiaolei; Monroe, Lyman; Bures, Mark G; Kihara, Daisuke

2014-08-27

Structure-based computational methods have been widely used in exploring protein-ligand interactions, including predicting the binding ligands of a given protein based on their structural complementarity. Compared to other protein and ligand representations, the advantages of a surface representation include reduced sensitivity to subtle changes in the pocket and ligand conformation and fast search speed. Here we developed a novel method named PL-PatchSurfer (Protein-Ligand PatchSurfer). PL-PatchSurfer represents the protein binding pocket and the ligand molecular surface as a combination of segmented surface patches. Each patch is characterized by its geometrical shape and the electrostatic potential, which are represented using the 3D Zernike descriptor (3DZD). We first tested PL-PatchSurfer on binding ligand prediction and found it outperformed the pocket-similarity based ligand prediction program. We then optimized the search algorithm of PL-PatchSurfer using the PDBbind dataset. Finally, we explored the utility of applying PL-PatchSurfer to a larger and more diverse dataset and showed that PL-PatchSurfer was able to provide a high early enrichment for most of the targets. To the best of our knowledge, PL-PatchSurfer is the first surface patch-based method that treats ligand complementarity at protein binding sites. We believe that using a surface patch approach to better understand protein-ligand interactions has the potential to significantly enhance the design of new ligands for a wide array of drug-targets.

PL-PatchSurfer: A Novel Molecular Local Surface-Based Method for Exploring Protein-Ligand Interactions

PubMed Central

Hu, Bingjie; Zhu, Xiaolei; Monroe, Lyman; Bures, Mark G.; Kihara, Daisuke

2014-01-01

Structure-based computational methods have been widely used in exploring protein-ligand interactions, including predicting the binding ligands of a given protein based on their structural complementarity. Compared to other protein and ligand representations, the advantages of a surface representation include reduced sensitivity to subtle changes in the pocket and ligand conformation and fast search speed. Here we developed a novel method named PL-PatchSurfer (Protein-Ligand PatchSurfer). PL-PatchSurfer represents the protein binding pocket and the ligand molecular surface as a combination of segmented surface patches. Each patch is characterized by its geometrical shape and the electrostatic potential, which are represented using the 3D Zernike descriptor (3DZD). We first tested PL-PatchSurfer on binding ligand prediction and found it outperformed the pocket-similarity based ligand prediction program. We then optimized the search algorithm of PL-PatchSurfer using the PDBbind dataset. Finally, we explored the utility of applying PL-PatchSurfer to a larger and more diverse dataset and showed that PL-PatchSurfer was able to provide a high early enrichment for most of the targets. To the best of our knowledge, PL-PatchSurfer is the first surface patch-based method that treats ligand complementarity at protein binding sites. We believe that using a surface patch approach to better understand protein-ligand interactions has the potential to significantly enhance the design of new ligands for a wide array of drug-targets. PMID:25167137

Patch testing in children from 2005 to 2012: results from the North American contact dermatitis group.

PubMed

Zug, Kathryn A; Pham, Anh Khoa; Belsito, Donald V; DeKoven, Joel G; DeLeo, Vincent A; Fowler, Joseph F; Fransway, Anthony F; Maibach, Howard I; Marks, James G; Mathias, C G Toby; Pratt, Melanie D; Sasseville, Denis; Storrs, Frances J; Taylor, James S; Warshaw, Erin M; Zirwas, Matthew J

2014-01-01

Allergic contact dermatitis is common in children. Epicutaneous patch testing is an important tool for identifying responsible allergens. The objective of this study was to provide the patch test results from children (aged ≤18 years) examined by the North American Contact Dermatitis Group from 2005 to 2012. This is a retrospective analysis of children patch-tested with the North American Contact Dermatitis Group 65- or 70-allergen series. Frequencies and counts were compared with previously published data (2001-2004) using χ statistics. A total of 883 children were tested during the study period. A percentage of 62.3% had ≥1 positive patch test and 56.7% had ≥1 relevant positive patch test. Frequencies of positive patch test and relevant positive patch test reaction were highest with nickel sulfate (28.1/25.6), cobalt chloride (12.3/9.1), neomycin sulfate (7.1/6.6), balsam of Peru (5.7/5.5), and lanolin alcohol 50% petrolatum vehicle (5.5/5.1). The ≥1 positive patch test and ≥1 relevant positive patch test in the children did not differ significantly from adults (≥19 years) or from previously tested children (2001-2004). The percentage of clinically relevant positive patch tests for 27 allergens differed significantly between the children and adults. A total of 23.6% of children had a relevant positive reaction to at least 1 supplemental allergen. Differences in positive patch test and relevant positive patch test frequencies between children and adults as well as test periods confirm the importance of reporting periodic updates of patch testing in children to enhance clinicians' vigilance to clinically important allergens.

Aortic valve repair with autologous pericardial patch.

PubMed

Lausberg, Henning F; Aicher, Diana; Langer, Frank; Schäfers, Hans-Joachim

2006-08-01

Isolated aortic valve repair (AVR) has been gaining increasing interest in recent times. Results of isolated aortic valve repair have been reported to be variable. Various techniques have been utilized. We analyzed our experience with isolated valve repair using autologous pericardial patch plasty and compared the results to an age-matched collective with aortic valve repair without the use of additional material. Between January 1997 and June 2005, pericardial patch plasty of the aortic valve was performed in 42 patients (PATCH). During the same period, 42 patients after AVR without the use of additional material were age matched (NO-PATCH). Mean age in both groups was 52 years with a majority of male patients (PATCH ratio, 3.7:1; NO-PATCH ratio, 5:1). Valve anatomy was similar in both groups. All patients were followed by echocardiography for a cumulative follow-up of 2341 patient months (mean 28+/-23 months). No patient died in the hospital in neither group. The average systolic gradient was 5.9+/-2.2 mmHg in PATCH and 4.8+/-2.1 mmHg in NO-PATCH; p=0.17). Freedom from aortic regurgitation > or = II degrees was 87.8% in PATCH and 95.0% in NO-PATCH after 5 years (p=0.21). Freedom from reoperation was 97.6% in PATCH and 97.4% in NO-PATCH (p=0.96). Aortic regurgitation can be treated effectively by aortic valve repair using pericardial patch plasty. The functional results are satisfactory. With the application of this technique also more complex pathologies of the aortic valve can be addressed adequately thus extending the concept of valve preservation in patients with aortic regurgitation.

Mate choice when males are in patches: optimal strategies and good rules of thumb.

PubMed

Hutchinson, John M C; Halupka, Konrad

2004-11-07

In standard mate-choice models, females encounter males sequentially and decide whether to inspect the quality of another male or to accept a male already inspected. What changes when males are clumped in patches and there is a significant cost to travel between patches? We use stochastic dynamic programming to derive optimum strategies under various assumptions. With zero costs to returning to a male in the current patch, the optimal strategy accepts males above a quality threshold which is constant whenever one or more males in the patch remain uninspected; this threshold drops when inspecting the last male in the patch, so returns may occur only then and are never to a male in a previously inspected patch. With non-zero within-patch return costs, such a two-threshold rule still performs extremely well, but a more gradual decline in acceptance threshold is optimal. Inability to return at all need not decrease performance by much. The acceptance threshold should also decline if it gets harder to discover the last males in a patch. Optimal strategies become more complex when mean male quality varies systematically between patches or years, and females estimate this in a Bayesian manner through inspecting male qualities. It can then be optimal to switch patch before inspecting all males on a patch, or, exceptionally, to return to an earlier patch. We compare performance of various rules of thumb in these environments and in ones without a patch structure. A two-threshold rule performs excellently, as do various simplifications of it. The best-of-N rule outperforms threshold rules only in non-patchy environments with between-year quality variation. The cutoff rule performs poorly.

Departure mechanisms for host search on high-density patches by the Meteorus pulchricornis.

PubMed

Sheng, Sheng; Feng, Sufang; Meng, Ling; Li, Baoping

2014-01-01

Less attention has been paid to the parasitoid-host system in which the host occurs in considerably high density with a hierarchical patch structure in studies on time allocation strategies of parasitoids. This study used the parasitoid Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae) and the Oriental leafworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) as the parasitoids-host model system to investigate patch-leaving mechanisms as affected by the high-host density, hierarchical patch structure, and foraging behaviors on both former and current patches. The results showed that three out of eight covariates tested had significant effects on the patch-leaving tendency, including the host density, ovipositor insertion, and host rejection on the current patch. The parasitoid paid more visits to the patch with high-density hosts. While the patch with higher host densities decreased the leaving tendency, the spatial distribution of hosts examined had no effect on the leaving tendency. Both oviposition and host rejection decreased the patch-leaving tendency. The variables associated with the former patch, such as the host density and number of ovipositor insertions, however, did not have an effect on the leaving tendency. Our study suggested that M. pulchricornis females may use an incremental mechanism to exploit high-density patches to the fullest. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

Scale-dependent feedbacks between patch size and plant reproduction in desert grassland

USGS Publications Warehouse

Svejcar, Lauren N.; Bestelmeyer, Brandon T.; Duniway, Michael C.; James, Darren K.

2015-01-01

Theoretical models suggest that scale-dependent feedbacks between plant reproductive success and plant patch size govern transitions from highly to sparsely vegetated states in drylands, yet there is scant empirical evidence for these mechanisms. Scale-dependent feedback models suggest that an optimal patch size exists for growth and reproduction of plants and that a threshold patch organization exists below which positive feedbacks between vegetation and resources can break down, leading to critical transitions. We examined the relationship between patch size and plant reproduction using an experiment in a Chihuahuan Desert grassland. We tested the hypothesis that reproductive effort and success of a dominant grass (Bouteloua eriopoda) would vary predictably with patch size. We found that focal plants in medium-sized patches featured higher rates of grass reproductive success than when plants occupied either large patch interiors or small patches. These patterns support the existence of scale-dependent feedbacks in Chihuahuan Desert grasslands and indicate an optimal patch size for reproductive effort and success in B. eriopoda. We discuss the implications of these results for detecting ecological thresholds in desert grasslands.

Current usage and future directions for the bovine pericardial patch.

PubMed

Li, Xin; Guo, Yuanyuan; Ziegler, Kenneth R; Model, Lynn S; Eghbalieh, Sammy D D; Brenes, Robert A; Kim, Susun T; Shu, Chang; Dardik, Alan

2011-05-01

Bovine pericardium (BP) is widely used in surgery and is commonly used as a patch after arteriotomy in cardiovascular surgery. BP patches have several advantages compared with prosthetic patches, including superior biocompatability, easy handling, less suture line bleeding, and possibly reduced rates of infection. These advantages of BP have led to its common use during carotid endarterectomy (CEA). However, long-term clinical results reported after CEA have suggested several issues that may be related to the patch, including restenosis, pseudoaneurysm formation, infection, fibrosis, calcification, and thrombosis. These complications may diminish the long-term efficacy of CEA and suggest potential areas for improvement of surgical patches. Understanding the mechanisms by which BP heals after patch angioplasty may lead to next generation tissue-engineered patches. Published by Elsevier Inc.

Current usage and future directions for the bovine pericardial patch

PubMed Central

Li, Xin; Guo, Yuanyuan; Ziegler, Kenneth; Model, Lynn; Eghbalieh, Sammy D. D.; Brenes, Robert; Kim, Susun; Shu, Chang; Dardik, Alan

2010-01-01

Bovine pericardium is widely used in surgery and is commonly used for a patch after arteriotomy during cardiovascular surgery. Bovine pericardial patches have several advantages compared to prosthetic patches, including superior biocompatability, easy handling, less suture line bleeding and possibly reduced rates of infection. These advantages of bovine pericardium have led to its common use during carotid endarterectomy. However, long-term clinical results reported after carotid endarterectomy have suggested several issues that may be related to the patch including restenosis, pseudoaneurysm formation, infection, fibrosis, calcification and thrombosis. These complications may diminish the long-term efficacy of carotid endarterectomy and suggest potential areas for improvement of surgical patches. Understanding the mechanisms by which bovine pericardium heals after patch angioplasty may lead to next generation tissue engineered patches. PMID:21276709

Integrated multiple patch-clamp array chip via lateral cell trapping junctions

NASA Astrophysics Data System (ADS)

Seo, J.; Ionescu-Zanetti, C.; Diamond, J.; Lal, R.; Lee, L. P.

2004-03-01

We present an integrated multiple patch-clamp array chip by utilizing lateral cell trapping junctions. The intersectional design of a microfluidic network provides multiple cell addressing and manipulation sites for efficient electrophysiological measurements at a number of patch sites. The patch pores consist of openings in the sidewall of a main fluidic channel, and a membrane patch is drawn into a smaller horizontal channel. This device geometry not only minimizes capacitive coupling between the cell reservoir and the patch channel, but also allows simultaneous optical and electrical measurements of ion channel proteins. Evidence of the hydrodynamic placement of mammalian cells at the patch sites as well as measurements of patch sealing resistance is presented. Device fabrication is based on micromolding of polydimethylsiloxane, thus allowing inexpensive mass production of disposable high-throughput biochips.

FuncPatch: a web server for the fast Bayesian inference of conserved functional patches in protein 3D structures.

PubMed

Huang, Yi-Fei; Golding, G Brian

2015-02-15

A number of statistical phylogenetic methods have been developed to infer conserved functional sites or regions in proteins. Many methods, e.g. Rate4Site, apply the standard phylogenetic models to infer site-specific substitution rates and totally ignore the spatial correlation of substitution rates in protein tertiary structures, which may reduce their power to identify conserved functional patches in protein tertiary structures when the sequences used in the analysis are highly similar. The 3D sliding window method has been proposed to infer conserved functional patches in protein tertiary structures, but the window size, which reflects the strength of the spatial correlation, must be predefined and is not inferred from data. We recently developed GP4Rate to solve these problems under the Bayesian framework. Unfortunately, GP4Rate is computationally slow. Here, we present an intuitive web server, FuncPatch, to perform a fast approximate Bayesian inference of conserved functional patches in protein tertiary structures. Both simulations and four case studies based on empirical data suggest that FuncPatch is a good approximation to GP4Rate. However, FuncPatch is orders of magnitudes faster than GP4Rate. In addition, simulations suggest that FuncPatch is potentially a useful tool complementary to Rate4Site, but the 3D sliding window method is less powerful than FuncPatch and Rate4Site. The functional patches predicted by FuncPatch in the four case studies are supported by experimental evidence, which corroborates the usefulness of FuncPatch. The software FuncPatch is freely available at the web site, http://info.mcmaster.ca/yifei/FuncPatch golding@mcmaster.ca Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Arbitrarily shaped dual-stacked patch antennas: A hybrid FEM simulation

NASA Technical Reports Server (NTRS)

Gong, Jian; Volakis, John L.

1995-01-01

A dual-stacked patch antenna is analyzed using a hybrid finite element - boundary integral (FE-BI) method. The metallic patches of the antenna are modeled as perfectly electric conducting (PEC) plates stacked on top of two different dielectric layers. The antenna patches may be of any shape and the lower patch is fed by a coaxial cable from underneath the ground plane or by an aperture coupled microstrip line. The ability of the hybrid FEM technique for the stacked patch antenna characterization will be stressed, and the EM coupling mechanism is also discussed with the aid of the computed near field patterns around the patches.

Scopolamine Transdermal Patch

MedlinePlus

... the adhesive surface of the patch, the clear plastic protective strip should be peeled off and discarded. ... needed, remove the patch and dispose of it. Wrap the patch in tissue or paper to avoid ...

Diclofenac Transdermal Patch

MedlinePlus

... will be applying the patch. Cut open the envelope containing the patches, cutting on the dotted line ... it. Pull apart the zipper seal on the envelope and remove one patch. Reseal the envelope by ...

Monitoring Pregnant Women’s Illicit Opiate and Cocaine Use With Sweat Testing

PubMed Central

Brunet, Bertrand R.; Barnes, Allan J.; Choo, Robin E.; Mura, Patrick; Jones, Hendrée E.; Huestis, Marilyn A.

2011-01-01

Dependence on illicit drugs during pregnancy is a major public health concern as there may be associated adverse maternal, fetal, and neonatal consequences. Sweat patches (n = 389) were collected from 39 pregnant volunteers who provided written informed consent for this Institutional Review Board-approved protocol and wore patches, replaced approximately weekly, from study entry until delivery. Patches were analyzed for opiates (heroin, 6-acetylmor-phine, 6-acetylcodeine, morphine and codeine) and cocaine (cocaine, benzoylecgonine, ecgonine methyl ester, anhydroecgonine methyl ester) by solid phase extraction and gas chromatography mass spectrometry. Seventy-one percent (276) of collected sweat patches were ≥5 ng per patch (limit of quantification) for one or more analytes. Cocaine was present in 254 (65.3%) patches in concentrations ranging from 5.2 to 11,835 ng per patch with 154 of these high enough to satisfy the proposed Substance Abuse and Mental Health Services Administration guidelines for a confirmatory drug test (25 ng per patch). Interestingly, 6-acetylmorphine was the most prominent opiate analyte documented in 134 patches (34.4%) with 11.3% exceeding the proposed opiate Substance Abuse and Mental Health Services Administration cut-off (25 ng per patch). Heroin was identified in fewer patches (77), but in a similar concentration range (5.3–345.4 ng per patch). Polydrug use was evident by the presence of both cocaine and opiate metabolites in 136 (35.0%) patches. Sweat testing is an effective method for monitoring abstinence or illicit drug use relapse in this high-risk population of pregnant opiate- and/or cocaine-dependent women. PMID:19927046

In vivo results of hydrogel composite pericardial substitutes.

PubMed

Blue, M A; Guilbeau, E J; Brandon, T A; Walker, A S; Bjotvedt, G; Fisk, R L

1991-01-01

In this study, two improved pericardial patches were developed and evaluated for their efficacy as pericardial substitutes. The patches are composites consisting of a hydrogel (PHEMA) that coats an underlying mesh (either ETFE or PET). Studies were conducted using subcutaneous implants in rats and pericardial patch implants in greyhound dogs. Adhesions between the substitute and pericardium and the epicardium were minimal. The ETFE composite patch caused an unacceptable epicardial reaction. The PET patch results were encouraging; the epicardium was largely unaffected by the patch.

Apparatus and Method for Improving the Gain and Bandwidth of a Microstrip Patch Antenna

DTIC Science & Technology

2013-09-30

improving both the gain and the bandwidth of a microstrip patch antenna . (2) Description of the Prior Art [0004] A patch antenna , also referred to as a...rectangular microstrip antenna , is a type of radio antenna with a low profile that can be mounted on a flat surface. The patch antenna includes a...patch antenna form a Attorney Docket No. 101925 2 of 11 resonant piece of microstrip transmission line. The patch is designed to have a length of

The effect of travel loss on evolutionarily stable distributions of populations in space

USGS Publications Warehouse

DeAngelis, D.L.; Wolkowicz, G.S.K.; Lou, Y.; Jiang, Y.; Novak, M.; Svanback, R.; Araujo, M.S.; Jo, Y.S.; Cleary, E.A.

2011-01-01

A key assumption of the ideal free distribution (IFD) is that there are no costs in moving between habitat patches. However, because many populations exhibit more or less continuous population movement between patches and traveling cost is a frequent factor, it is important to determine the effects of costs on expected population movement patterns and spatial distributions. We consider a food chain (tritrophic or bitrophic) in which one species moves between patches, with energy cost or mortality risk in movement. In the two-patch case, assuming forced movement in one direction, an evolutionarily stable strategy requires bidirectional movement, even if costs during movement are high. In the N-patch case, assuming that at least one patch is linked bidirectionally to all other patches, optimal movement rates can lead to source-sink dynamics where patches with negative growth rates are maintained by other patches with positive growth rates. As well, dispersal between patches is not balanced (even in the two-patch case), leading to a deviation from the IFD. Our results indicate that cost-associated forced movement can have important consequences for spatial metapopulation dynamics. Relevance to marine reserve design and the study of stream communities subject to drift is discussed. ?? 2011 by The University of Chicago.

Response to rivastigmine transdermal patch or memantine plus rivastigmine patch is affected by apolipoprotein E genotype in Alzheimer patients.

PubMed

Han, Hyun Jeong; Kim, Byeong C; Lee, Jun-Young; Ryu, Seung-Ho; Na, Hae Ri; Yoon, Soo Jin; Park, Hyun Young; Shin, Joon Hyun; Cho, Soo-Jin; Yi, Hyon-Ah; Choi, Mun Seong; Heo, Jae-Hyeok; Park, Kyung Won; Kim, Kwang K; Choi, Seong Hye

2012-01-01

The apolipoprotein E (APOE) genotype in response to pharmacological treatments in patients with Alzheimer's disease (AD) remains a matter of controversy. This analysis investigated the effect of the APOE genotype on the clinical response to rivastigmine transdermal patch monotherapy or memantine plus rivastigmine patch in patients with mild to moderate AD. Two hundred and six (n = 206) patients with probable AD and Mini-Mental State Examination (MMSE) scores of 10-20 were randomized to rivastigmine patch monotherapy or memantine plus rivastigmine patch for 24 weeks. Of the 206 patients with probable AD, 146 patients who consented to genetic testing for APOE were included and assessed for this subgroup study. There were no significant differences on MMSE, NPI, ADAS-cog, ADCS-ADL, CDR-SB, NPI and FAB between rivastigmine patch monotherapy and memantine plus rivastigmine patch according to the APOE genotype. However, patients with moderately severe AD (MMSE ≤15) who were APOE ε4 carriers showed higher responder rates on ADCS-ADL with memantine plus rivastigmine patch compared to rivastigmine patch monotherapy. Moderately severe AD patients with the APOE ε4 allele may respond more favorably to memantine plus rivastigmine patch than ε4 noncarriers. Copyright © 2012 S. Karger AG, Basel.

On the Persistent Shape and Coherence of Pulsating Auroral Patches

NASA Astrophysics Data System (ADS)

Humberset, B. K.; Gjerloev, J. W.; Mann, I. R.; Michell, R. G.; Samara, M.

2018-05-01

The pulsating aurora covers a broad range of fluctuating shapes that are poorly characterized. The purpose of this paper is therefore to provide objective and quantitative measures of the extent to which pulsating auroral patches maintain their shape, drift and fluctuate in a coherent fashion. We present results from a careful analysis of pulsating auroral patches using all-sky cameras. We have identified four well-defined individual patches that we follow in the patch frame of reference. In this way we avoid the space-time ambiguity which complicates rocket and satellite measurements. We find that the shape of the patches is remarkably persistent with 85-100% of the patch being repeated for 4.5-8.5 min. Each of the three largest patches has a temporal correlation with a negative dependence on distance, and thus does not fluctuate in a coherent fashion. A time-delayed response within the patches indicates that the so-called streaming mode might explain the incoherency. The patches appear to drift differently from the SuperDARN-determined E→×B→ convection velocity. However, in a nonrotating reference frame the patches drift with 230-287 m/s in a north eastward direction, which is what typically could be expected for the convection return flow.

Landscape matrix mediates occupancy dynamics of Neotropical avian insectivores

USGS Publications Warehouse

Kennedy, Christina M.; Campbell Grant, Evan H.; Neel, Maile C.; Fagan, William F.; Marpa, Peter P.

2011-01-01

In addition to patch-level attributes (i.e., area and isolation), the nature of land cover between habitat patches (the matrix) may drive colonization and extinction dynamics in fragmented landscapes. Despite a long-standing recognition of matrix effects in fragmented systems, an understanding of the relative impacts of different types of land cover on patterns and dynamics of species occurrence remains limited. We employed multi-season occupancy models to determine the relative influence of patch area, patch isolation, within-patch vegetation structure, and landscape matrix on occupancy dynamics of nine Neotropical nsectivorous birds in 99 forest patches embedded in four matrix types (agriculture, suburban evelopment, bauxite mining, and forest) in central Jamaica. We found that within-patch vegetation structure and the matrix type between patches were more important than patch area and patch isolation in determining local colonization and local extinction probabilities, and that the effects of patch area, isolation, and vegetation structure on occupancy dynamics tended to be matrix and species dependent. Across the avian community, the landscape matrix influenced local extinction more than local colonization, indicating that extinction processes, rather than movement, likely drive interspecific differences in occupancy dynamics. These findings lend crucial empirical support to the hypothesis that species occupancy dynamics in fragmented systems may depend greatly upon the landscape context.

Comparing reliabilities of strip and conventional patch testing.

PubMed

Dickel, Heinrich; Geier, Johannes; Kreft, Burkhard; Pfützner, Wolfgang; Kuss, Oliver

2017-06-01

The standardized protocol for performing the strip patch test has proven to be valid, but evidence on its reliability is still missing. To estimate the parallel-test reliability of the strip patch test as compared with the conventional patch test. In this multicentre, prospective, randomized, investigator-blinded reliability study, 132 subjects were enrolled. Simultaneous duplicate strip and conventional patch tests were performed with the Finn Chambers ® on Scanpor ® tape test system and the patch test preparations nickel sulfate 5% pet., potassium dichromate 0.5% pet., and lanolin alcohol 30% pet. Reliability was estimated by the use of Cohen's kappa coefficient. Parallel-test reliability values of the three standard patch test preparations turned out to be acceptable, with slight advantages for the strip patch test. The differences in reliability were 9% (95%CI: -8% to 26%) for nickel sulfate and 23% (95%CI: -16% to 63%) for potassium dichromate, both favouring the strip patch test. The standardized strip patch test method for the detection of allergic contact sensitization in patients with suspected allergic contact dermatitis is reliable. Its application in routine clinical practice can be recommended, especially if the conventional patch test result is presumably false negative. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A comparison of bleeding patterns and cycle control using two transdermal contraceptive systems: a multicenter, open-label, randomized study.

PubMed

Gruber, D; Skřivánek, A; Serrani, M; Lanius, V; Merz, M

2015-02-01

To investigate the bleeding pattern and cycle control parameters of a contraceptive patch containing 0.55 mg ethinyl estradiol (EE) and 2.1 mg gestodene (GSD) compared with a patch containing 0.6 mg EE and 6 mg norelgestromin (NGMN). In this phase III, open-label, randomized, parallel-group trial, healthy women aged 18-35 years (smokers aged 18-30 years) received either the EE/GSD patch (n=200) or the EE/NGMN patch (n=198). Treatment consisted of one patch per week for 3 weeks followed by a 7-day, patch-free interval for seven cycles. Bleeding control was assessed in two 90-day reference periods. In reference period 1, mean number of bleeding/spotting days was comparable across treatment groups (p>0.05). However, in reference period 2, there were fewer bleeding/spotting days in the EE/GSD patch group (15.7 versus 18.4; p<0.0001). Mean number of bleeding/spotting episodes was comparable across groups for both reference periods, but bleeding/spotting episodes were shorter for the EE/GSD patch than the EE/NGMN patch during reference period 1 (5.13 days versus 5.53 days, respectively; p<0.05) and reference period 2 (5.07 versus 5.66; p=0.0001). Both treatment groups showed a similar frequency of withdrawal bleeding episodes; however, across all seven cycles, the length of these episodes was consistently shorter with the EE/GSD patch (p<0.01). There were no notable treatment differences in intracyclic bleeding. Bleeding pattern and cycle control achieved with the EE/GSD patch was similar to that of the EE/NGMN patch. The paper presents data on the bleeding pattern and cycle control parameters of an investigational transdermal contraceptive patch containing EE and GSD compared with an approved contraceptive patch containing EE and NGMN. This descriptive study found that bleeding patterns associated with the EE/GSD patch were similar to those of an EE/NGMN patch providing higher EE exposure. Copyright © 2015 Elsevier Inc. All rights reserved.

Transdermal patches: history, development and pharmacology

PubMed Central

Pastore, Michael N; Kalia, Yogeshvar N; Horstmann, Michael; Roberts, Michael S

2015-01-01

Transdermal patches are now widely used as cosmetic, topical and transdermal delivery systems. These patches represent a key outcome from the growth in skin science, technology and expertise developed through trial and error, clinical observation and evidence-based studies that date back to the first existing human records. This review begins with the earliest topical therapies and traces topical delivery to the present-day transdermal patches, describing along the way the initial trials, devices and drug delivery systems that underpin current transdermal patches and their actives. This is followed by consideration of the evolution in the various patch designs and their limitations as well as requirements for actives to be used for transdermal delivery. The properties of and issues associated with the use of currently marketed products, such as variability, safety and regulatory aspects, are then described. The review concludes by examining future prospects for transdermal patches and drug delivery systems, such as the combination of active delivery systems with patches, minimally invasive microneedle patches and cutaneous solutions, including metered-dose systems. PMID:25560046

Effects of Sediment Patches on Sediment Transport Predictions in Steep Mountain Channels

NASA Astrophysics Data System (ADS)

Monsalve Sepulveda, A.; Yager, E.

2013-12-01

Bed surface patches occur in most gravel-bedded rivers and in steep streams can be divided between relatively immobile boulders and more mobile patches of cobbles and gravel. This spatial variability in grain size, roughness and sorting impact bed load transport by altering the relative local mobility of different grain sizes and creating complex local flow fields. Large boulders also bear a significant part of the total shear stress and we hypothesize that the remaining shear stress on a given mobile patch is a distribution of values that depend on the local topography, patch type and location relative to the large roughness elements and thalweg. Current sediment transport equations do not account for the variation in roughness, local flow and grain size distributions on and between patches and often use an area-weighted approach to obtain a representative grain size distribution and reach-averaged shear stress. Such equations also do not distinguish between active (patches where at least one grain size is in motion) and inactive patches or include the difference in mobility between patch classes as result of spatial shear stress distributions. To understand the effects of sediment patches on sediment transport in steep channels, we calculated the shear stress distributions over a range of patch classes in a 10% gradient step-pool stream. We surveyed the bed with a high density resolution (every 5 cm in horizontal and vertical directions over a 40 m long reach) using a total station and terrestrial LiDAR, mapped and classified patches by their grain size distributions, and measured water surface elevations and mean velocities for low to moderate flow events. Using these data we calibrated a quasi-three dimensional model (FaSTMECH) to obtain shear stress distributions over each patch for a range of flow discharges. We modified Parker's (1990) equations to use the calculated shear stress distribution, measured grain sizes, and a specific hiding function for each patch class, and then added the bedload fluxes for each patch to calculate the reach-averaged sediment transport rate. Sediment mobility in patches was highly dependent on the patch's class and location relative to the thalweg and large roughness elements. Compared to deterministic formulations, the use of distributions of shear stress improved predictions of bedload transport in steep mountain channels.

Patch size has no effect on insect visitation rate per unit area in garden-scale flower patches

NASA Astrophysics Data System (ADS)

Garbuzov, Mihail; Madsen, Andy; Ratnieks, Francis L. W.

2015-01-01

Previous studies investigating the effect of flower patch size on insect flower visitation rate have compared relatively large patches (10-1000s m2) and have generally found a negative relationship per unit area or per flower. Here, we investigate the effects of patch size on insect visitation in patches of smaller area (range c. 0.1-3.1 m2), which are of particular relevance to ornamental flower beds in parks and gardens. We studied two common garden plant species in full bloom with 6 patch sizes each: borage (Borago officinalis) and lavender (Lavandula × intermedia 'Grosso'). We quantified flower visitation by insects by making repeated counts of the insects foraging at each patch. On borage, all insects were honey bees (Apis mellifera, n = 5506 counts). On lavender, insects (n = 737 counts) were bumble bees (Bombus spp., 76.9%), flies (Diptera, 22.4%), and butterflies (Lepidoptera, 0.7%). On both plant species we found positive linear effects of patch size on insect numbers. However, there was no effect of patch size on the number of insects per unit area or per flower and, on lavender, for all insects combined or only bumble bees. The results show that it is possible to make unbiased comparisons of the attractiveness of plant species or varieties to flower-visiting insects using patches of different size within the small scale range studied and make possible projects aimed at comparing ornamental plant varieties using existing garden flower patches of variable area.

Patching. Restitching business portfolios in dynamic markets.

PubMed

Eisenhardt, K M; Brown, S L

1999-01-01

In turbulent markets, businesses and opportunities are constantly falling out of alignment. New technologies and emerging markets create fresh opportunities. Converging markets produce more. And of course, some markets fade. In this landscape of continuous flux, it's more important to build corporate-level strategic processes that enable dynamic repositioning than it is to build any particular defensible position. That's why smart corporate strategists use patching, a process of mapping and remapping business units to create a shifting mix of highly focused, tightly aligned businesses that can respond to changing market opportunities. Patching is not just another name for reorganizing; patchers have a distinctive mindset. Traditional managers see structure as stable; patching managers believe structure is inherently temporary. Traditional managers set corporate strategy first, but patching managers keep the organization focused on the right set of business opportunities and let strategy emerge from individual businesses. Although the focus of patching is flexibility, the process itself follows a pattern. Patching changes are usually small in scale and made frequently. Patching should be done quickly; the emphasis is on getting the patch about right and fixing problems later. Patches should have a test drive before they're formalized but then be tightly scripted after they've been announced. And patching won't work without the right infrastructure: modular business units, fine-grained and complete unit-level metrics, and companywide compensation parity. The authors illustrate how patching works and point out some common stumbling blocks.

Pharmacokinetic overview of ethinyl estradiol dose and bioavailability using two transdermal contraceptive systems and a standard combined oral contraceptive

PubMed Central

Hofmann, Birte; Reinecke, Isabel; Schuett, Barbara; Merz, Martin; Zurth, Christian

2014-01-01

Objective: To determine the relative bioavailability of ethinyl estradiol (EE) and gestodene (GSD) after application of a novel transdermal contraceptive patch vs. a standard combined oral contraceptive (COC) pill (study 1), and to evaluate the pharmacokinetics (PK) of EE after application of the EE/GSD patch compared with an EE/norelgestromin (NGMN) patch (study 2). Materials: Participants were healthy, non-obese women aged 18 – 45 years (study 1) or 18 – 35 years (study 2). Compositions of study treatments were as follows: 0.55 mg EE/2.1 mg GSD (EE/GSD patch); 0.02 mg EE/0.075 mg GSD (standard COC); 0.6 mg EE/6 mg NGMN (EE/NGMN patch). Methods: In study 1, which consisted of 3 treatment periods (each followed by 7 patch- or pill-free days), treatments were administered in one of two randomized orders: either P–M–E (EE/GSD patch (P) every 7 days for 28 days → COC (M) once-daily for 21 days → two 7-day patch-wearing periods followed by one 10-day patch-wearing phase (E)), or the same treatments administered in sequence M–P–E. For study 2, participants received either the EE/GSD patch or EE/NGMN patch for seven treatment cycles (one patch per week for 3 weeks followed by a 7-day patch-free interval). Results: In study 1, average daily exposure to EE was similar for treatments P and M; the mean daily area under the concentration-time curve (AUC) ratio of treatment P vs. treatment M for EE was 1.06 (90% confidence interval (CI): 0.964 – 1.16), indicating average daily delivery similar to oral administration of 0.019 – 0.023 mg EE. For unbound GSD, average daily exposure was lower for treatment P vs. treatment M. The mean AUC ratio of treatment P vs. treatment M for unbound GSD was 0.820 (90% CI: 0.760 – 0.885), indicating average daily delivery from the patch of 0.057 – 0.066 mg GSD. Prolonged patch wearing did not result in a distinct decline in GSD and EE serum concentrations. In study 2, AUC at steady state (AUC0–168,ss), average steady-state serum concentration, and maximum steady-state serum concentration for EE was 2.0 – 2.7-fold higher for the EE/NGMN patch vs. the EE/GSD patch. The EE/GSD patch was well tolerated in both studies. Conclusions: Based on the 90% CI of the AUC ratio of oral treatment vs. patch application for unbound GSD and EE, the daily doses of GSD and EE released from the EE/GSD patch over the 7-day application period provided the same systemic exposure as those recorded after daily oral administration of a COC containing 0.02 mg EE and 0.06 mg GSD. The EE/GSD patch showed reduced EE exposure compared with the EE/NGMN patch. Together with its good tolerability, these properties support the EE/GSD patch as an effective and well-tolerated alternative to available transdermal and oral contraceptives. PMID:25295716

Reproducible, high performance patch antenna array apparatus and method of fabrication

DOEpatents

Strassner, II, Bernd H.

2007-01-23

A reproducible, high-performance patch antenna array apparatus includes a patch antenna array provided on a unitary dielectric substrate, and a feed network provided on the same unitary substrate and proximity coupled to the patch antenna array. The reproducibility is enhanced by using photolithographic patterning and etching to produce both the patch antenna array and the feed network.

Methods of Making and Using Shape Memory Polymer Composite Patches

NASA Technical Reports Server (NTRS)

Hood, Patrick J.

2011-01-01

A method of repairing a composite component having a damaged area including: laying a composite patch over the damaged area: activating the shape memory polymer resin to easily and quickly mold said patch to said damaged area; deactivating said shape memory polymer so that said composite patch retains the molded shape; and bonding said composite patch to said damaged part.

Conserving Tropical Tree Diversity and Forest Structure: The Value of Small Rainforest Patches in Moderately-Managed Landscapes

PubMed Central

Hernández-Ruedas, Manuel A.; Arroyo-Rodríguez, Víctor; Meave, Jorge A.; Martínez-Ramos, Miguel; Ibarra-Manríquez, Guillermo; Martínez, Esteban; Jamangapé, Gilberto; Melo, Felipe P. L.; Santos, Bráulio A.

2014-01-01

Rainforests are undergoing severe deforestation and fragmentation worldwide. A huge amount of small forest patches are being created, but their value in conserving biodiversity and forest structure is still controversial. Here, we demonstrate that in a species-rich and moderately-managed Mexican tropical landscape small rainforest patches (<100 ha) can be highly valuable for the conservation of tree diversity and forest structure. These patches showed diverse communities of native plants, including endangered species, and a new record for the country. Although the number of logged trees increased in smaller patches, patch size was a poor indicator of basal area, stem density, number of species, genera and families, and community evenness. Cumulative species-area curves indicated that all patches had a similar contribution to the regional species diversity. This idea also was supported by the fact that patches strongly differed in floristic composition (high β-diversity), independently of patch size. Thus, in agreement with the land-sharing approach, our findings support that small forest patches in moderately-managed landscapes should be included in conservation initiatives to maintain landscape heterogeneity, species diversity, and ecosystem services. PMID:24901954

Slime moulds use heuristics based on within-patch experience to decide when to leave.

PubMed

Latty, Tanya; Beekman, Madeleine

2015-04-15

Animals foraging in patchy, non-renewing or slowly renewing environments must make decisions about how long to remain within a patch. Organisms can use heuristics ('rules of thumb') based on available information to decide when to leave the patch. Here, we investigated proximate patch-departure heuristics in two species of giant, brainless amoeba: the slime moulds Didymium bahiense and Physarum polycephalum. We explicitly tested the importance of information obtained through experience by eliminating chemosensory cues of patch quality. In P. polycephalum, patch departure was influenced by the consumption of high, and to a much lesser extent low, quality food items such that engulfing a food item increased patch-residency time. Physarum polycephalum also tended to forage for longer in darkened, 'safe' patches. In D. bahiense, engulfment of any food item increased patch residency irrespective of that food item's quality. Exposure to light had no effect on the patch-residency time of D. bahiense. Given that these organisms lack a brain, our results illustrate how the use of simple heuristics can give the impression that individuals make sophisticated foraging decisions. © 2015. Published by The Company of Biologists Ltd.

Isolation and functional characteristics of adherent phagocytic cells from mouse Peyer's patches.

PubMed Central

MacDonald, T T; Carter, P B

1982-01-01

Attempts were made to isolate adherent phagocytic cells (macrophages) from mouse Peyer's patch cell suspensions. Cell suspensions prepared by teasing apart the Peyer's patches contained no adherent phagocytic cells. However, if Peyer's patch fragments were treated with collagenase to disrupt the tissue matrix, cells prepared in this way contained a subpopulation of adherent phagocytic cells. These cells comprised only 0.1-0.2% of the total nucleated cell population of the Peyer's patch. Similar cells could also be isolated from the Peyer's patches of germ-free mice, but as judged by their ability to ingest opsonized erythrocytes, these cells were less activated than cells from the Peyer's patches of normal mice. Adherent cells from the Peyer's patches of normal mice could present antigen (ovalbumin) to T cells, and Peyer's patches cell suspensions containing adherent cells could be stimulated in vitro to produce an anti-sheep red blood cell plaque-forming cell response in the absence of 2-mercaptoethanol. These studies show that although the frequency of phagocytic adherent cells is extremely low in Peyer's patches, these cells have functions consistent with that of adherent cells in other lymphoid tissues. PMID:7068173

Conserving tropical tree diversity and forest structure: the value of small rainforest patches in moderately-managed landscapes.

PubMed

Hernández-Ruedas, Manuel A; Arroyo-Rodríguez, Víctor; Meave, Jorge A; Martínez-Ramos, Miguel; Ibarra-Manríquez, Guillermo; Martínez, Esteban; Jamangapé, Gilberto; Melo, Felipe P L; Santos, Bráulio A

2014-01-01

Rainforests are undergoing severe deforestation and fragmentation worldwide. A huge amount of small forest patches are being created, but their value in conserving biodiversity and forest structure is still controversial. Here, we demonstrate that in a species-rich and moderately-managed Mexican tropical landscape small rainforest patches (<100 ha) can be highly valuable for the conservation of tree diversity and forest structure. These patches showed diverse communities of native plants, including endangered species, and a new record for the country. Although the number of logged trees increased in smaller patches, patch size was a poor indicator of basal area, stem density, number of species, genera and families, and community evenness. Cumulative species-area curves indicated that all patches had a similar contribution to the regional species diversity. This idea also was supported by the fact that patches strongly differed in floristic composition (high β-diversity), independently of patch size. Thus, in agreement with the land-sharing approach, our findings support that small forest patches in moderately-managed landscapes should be included in conservation initiatives to maintain landscape heterogeneity, species diversity, and ecosystem services.

A localized flare of dermatitis may render patch tests uninterpretable in some patients with recently controlled widespread dermatitis.

PubMed

Magembe, Anna J; Davis, Mark D P; Richardson, Donna M

2009-01-01

Patch testing rarely is confounded by localized dermatitis induced in the area being tested (usually the back). Its occurrence renders the interpretation of patch tests impossible. To review our experience of the circumstances in which this phenomenon occurs during patch testing. We retrospectively reviewed patients with this phenomenon who underwent patch testing from January 1, 2002, through June 30, 2006. Of the 3,569 patients tested, 12 (0.34% [9 men and 3 women]) had development of this phenomenon. All patients previously had recent widespread dermatitis that was suppressed temporarily with topical corticosteroids and wet dressings at the time of patch testing. The period between control of the dermatitis and the initiation of patch testing was less than 1 week for all patients. Three patients (25%) had recently discontinued therapy with systemic corticosteroids (less than 1 week earlier). In patients with irritable skin either immediately after widespread dermatitis is controlled or after the cessation of systemic corticosteroid treatment, a flare of dermatitis induced by patch testing may render patch tests unreadable and therefore uninterpretable. To avoid this confounding occurrence, a waiting period between control of widespread dermatitis and initiation of patch testing is advised.

Ungulates rely less on visual cues, but more on adapting movement behaviour, when searching for forage.

PubMed

Venter, Jan A; Prins, Herbert H T; Mashanova, Alla; Slotow, Rob

2017-01-01

Finding suitable forage patches in a heterogeneous landscape, where patches change dynamically both spatially and temporally could be challenging to large herbivores, especially if they have no a priori knowledge of the location of the patches. We tested whether three large grazing herbivores with a variety of different traits improve their efficiency when foraging at a heterogeneous habitat patch scale by using visual cues to gain a priori knowledge about potential higher value foraging patches. For each species (zebra ( Equus burchelli ), red hartebeest ( Alcelaphus buselaphus subspecies camaa ) and eland ( Tragelaphus oryx )), we used step lengths and directionality of movement to infer whether they were using visual cues to find suitable forage patches at a habitat patch scale. Step lengths were significantly longer for all species when moving to non-visible patches than to visible patches, but all movements showed little directionality. Of the three species, zebra movements were the most directional. Red hartebeest had the shortest step lengths and zebra the longest. We conclude that these large grazing herbivores may not exclusively use visual cues when foraging at a habitat patch scale, but would rather adapt their movement behaviour, mainly step length, to the heterogeneity of the specific landscape.

PATIENTS' KNOWLEDGE OF MEDICAL PATCHES IN HUNGARY.

PubMed

Somogyi, Orsolya; Zelko, Romana

2016-11-01

Transdermal therapy with medical patches is a simple possibility in home medication. As the correct use of patches has a decisive impact from the point of its modulator effect.A questionnaire survey was developed to explore level of patients' knowledge of the correct use of transdermal patches. A survey was administered in thirteen Hungarian community pharmacies from October of 2012 to May of 2015. Most of the participants, men and women over 18 years of age (n = 233), used major analgesic patches (fentanyl); the remainder were given nitroglycerin, NSAID analgesics patches during the survey. For the hypothesis testing it was assumed that men were more likely to use a razor for skin depilation before patch application than women as their denser pelage hinders patch adhesion. The hypothesis testing showed no significant gender difference in razor use (X² = 0.201; p = 0.654). Pharmacists should direct patients to avoid using soap for skin cleansing before patch application because only 22 percent of the participants always avoided its use. Since only 9 tests were flawless from 233 completed questionnaires. Many patients do not understand how to correctly apply a transdermal dosage patch. Pharmacists should teach their correct application based on results.

A New Technique for System-to-system Transfer of Surface Data

NASA Technical Reports Server (NTRS)

Sterling, M. W.; Lucius, M. E.; Gordon, W. J.

1985-01-01

The purpose is to describe a recently developed technique aimed at providing a universal interface between surface types. In brief, a software package was developed which functions a common denominator of CAD/CAM surface types. This software enable one to convert from any given surface representation to any other target representation. The tiles maintain the same slope continuity as the target surface gram, bicubic patches are used since they allow one to match point, slope, and twist vectors to the target surface. Thus, slopes can be continuous or discontinuous as they are on the target surface. The patches can be of lower order if desired. For example, if only point information is available, the patches produced will be bilinear; however, the number of patches required is likely to increase correspondingly. The patches can be of higher order although many systems will not accept patches of more than order four. The final result of the program is a rectangular grid of bicubic patches. The patches fit the target surface exactly at their corners. Also, the patch corners have the same tangent and twist vectors. Adjacent patches will have slope continuity, unless a discontinuity was indicated by the target surface.

Role of Bacterial Communities in the Natural Suppression of Rhizoctonia solani Bare Patch Disease of Wheat (Triticum aestivum L.)

PubMed Central

Yin, Chuntao; Hulbert, Scot H.; Schroeder, Kurtis L.; Mavrodi, Olga; Mavrodi, Dmitri; Dhingra, Amit; Schillinger, William F.

2013-01-01

Rhizoctonia bare patch and root rot disease of wheat, caused by Rhizoctonia solani AG-8, develops as distinct patches of stunted plants and limits the yield of direct-seeded (no-till) wheat in the Pacific Northwest of the United States. At the site of a long-term cropping systems study near Ritzville, WA, a decline in Rhizoctonia patch disease was observed over an 11-year period. Bacterial communities from bulk and rhizosphere soil of plants from inside the patches, outside the patches, and recovered patches were analyzed by using pyrosequencing with primers designed for 16S rRNA. Taxa in the class Acidobacteria and the genus Gemmatimonas were found at higher frequencies in the rhizosphere of healthy plants outside the patches than in that of diseased plants from inside the patches. Dyella and Acidobacteria subgroup Gp7 were found at higher frequencies in recovered patches. Chitinophaga, Pedobacter, Oxalobacteriaceae (Duganella and Massilia), and Chyseobacterium were found at higher frequencies in the rhizosphere of diseased plants from inside the patches. For selected taxa, trends were validated by quantitative PCR (qPCR), and observed shifts of frequencies in the rhizosphere over time were duplicated in cycling experiments in the greenhouse that involved successive plantings of wheat in Rhizoctonia-inoculated soil. Chryseobacterium soldanellicola was isolated from the rhizosphere inside the patches and exhibited significant antagonism against R. solani AG-8 in vitro and in greenhouse tests. In conclusion, we identified novel bacterial taxa that respond to conditions affecting bare patch disease symptoms and that may be involved in suppression of Rhizoctonia root rot and bare batch disease. PMID:24056471

Habitat fragmentation influences nestling growth in Mediterranean blue and great tits

NASA Astrophysics Data System (ADS)

Bueno-Enciso, Javier; Ferrer, Esperanza S.; Barrientos, Rafael; Serrano-Davies, Eva; Sanz, Juan José

2016-01-01

In patchy forest areas, the size of the forest patch where birds breed has a strong influence on their breeding success. However, the proximate effects contributing to lowering the breeding success in small forest patches remain unclear; and a shortage of crucial resources in those forest patches has been suggested to account in some degree for this failure. With the aim to further investigate this issue, we have monitored the breeding cycle of blue and great tits in three 'large' forest patches (ranging between 26.5 and 29.6 ha) and twelve 'small' forest patches (ranging between 1.1 and 2.1 ha) in a Mediterranean area in central Spain, during three years (2011-2013). We also recorded the nestling diet inside the nest-boxes with the aid of handy-cams. Only males significantly differed between forest patch size categories; being on average younger and with better body condition in small patches for great and blue tits respectively. Reproductive traits did not vary between forest patch size categories, but the body condition of blue tit nestlings and the size of great tit nestlings did, being significantly better and larger respectively in large forest patches. The recruitment rate of blue tit nestlings was also higher in large patches. Regarding nestling diet, blue tits did not differ but great tits did, delivering a larger amount of caterpillars in large forest patches. Most variation in the reproductive traits occurred between years, probably due to annual differences in environmental conditions. This study suggests that food supply could be limiting the breeding success of birds above all in small patches, but also in large patches under particular environmental conditions.

Spatial Factors in the Integration of Speed Information

NASA Technical Reports Server (NTRS)

Verghese, P.; Stone, L. S.; Hargens, Alan R. (Technical Monitor)

1995-01-01

We reported that, for a 21FC task with multiple Gabor patches in each interval, thresholds for speed discrimination decreased with the number of patches, while simply increasing the area of a single patch produced no such effect. This result could be explained by multiple patches reducing spatial uncertainty. However, the fact that thresholds decrease with number even when the patches are in fixed positions argues against this explanation. We therefore performed additional experiments to explore the lack of an area effect. Three observers did a 21FC speed discrimination task with 6 Gabor patches in each interval, and were asked to pick the interval in which the gratings moved faster. The 50% contrast patches were placed on a circle at 4 deg. eccentricity, either equally spaced and maximally separated (hexagonal array), or closely-spaced, in consecutive positions (string of pearls). For the string-of-pearls condition, the grating phases were either random, or consistent with a full-field grating viewed through multiple Gaussian windows. When grating phases were random, the thresholds for the hexagonal and string-of-pearls layouts were indistinguishable. For the string-of-pearls layout, thresholds in the consistent-phase condition were higher by 15 +/- 6% than in the random-phase condition. (Thresholds increased by 57 +/- 7% in going from 6 patches to a single patch of equivalent area.). For random-phase patches, the lower thresholds for 6 patches does not depend on a specific spacing or spatial layout. Multiple, closely-spaced, consistent-phase patches that can be interpreted as a single grating, result in thresholds closer to that produced by a single patch. Together, our results suggest that object segmentation may play a role in the integration of speed information.

Whole-Cell Electrical Activity Under Direct Mechanical Stimulus by AFM Cantilever Using Planar Patch Clamp Chip Approach

PubMed Central

Upadhye, Kalpesh V.; Candiello, Joseph E.; Davidson, Lance A.; Lin, Hai

2011-01-01

Patch clamp is a powerful tool for studying the properties of ion-channels and cellular membrane. In recent years, planar patch clamp chips have been fabricated from various materials including glass, quartz, silicon, silicon nitride, polydimethyl-siloxane (PDMS), and silicon dioxide. Planar patch clamps have made automation of patch clamp recordings possible. However, most planar patch clamp chips have limitations when used in combination with other techniques. Furthermore, the fabrication methods used are often expensive and require specialized equipments. An improved design as well as fabrication and characterization of a silicon-based planar patch clamp chip are described in this report. Fabrication involves true batch fabrication processes that can be performed in most common microfabrication facilities using well established MEMS techniques. Our planar patch clamp chips can form giga-ohm seals with the cell plasma membrane with success rate comparable to existing patch clamp techniques. The chip permits whole-cell voltage clamp recordings on variety of cell types including Chinese Hamster Ovary (CHO) cells and pheochromocytoma (PC12) cells, for times longer than most available patch clamp chips. When combined with a custom microfluidics chamber, we demonstrate that it is possible to perfuse the extra-cellular as well as intra-cellular buffers. The chamber design allows integration of planar patch clamp with atomic force microscope (AFM). Using our planar patch clamp chip and microfluidics chamber, we have recorded whole-cell mechanosensitive (MS) currents produced by directly stimulating human keratinocyte (HaCaT) cells using an AFM cantilever. Our results reveal the spatial distribution of MS ion channels and temporal details of the responses from MS channels. The results show that planar patch clamp chips have great potential for multi-parametric high throughput studies of ion channel proteins. PMID:22174731

Lidocaine patches reduce pain in trauma patients with rib fractures.

PubMed

Zink, Karen A; Mayberry, John C; Peck, Ellen G; Schreiber, Martin A

2011-04-01

Rib fracture pain is notoriously difficult to manage. The lidocaine patch is effective in other pain scenarios with an excellent safety profile. This study assesses the efficacy of lidocaine patches for treating rib fracture pain. A prospectively gathered cohort of patients with rib fracture was retrospectively analyzed for use of lidocaine patches. Patients treated with lidocaine patches were matched to control subjects treated without patches. Subjective pain reports and narcotic use before and after patch placement, or equivalent time points for control subjects, were gathered from the chart. All patients underwent long-term follow-up, including a McGill Pain Questionnaire (MPQ). Twenty-nine patients with lidocaine patches (LP) and 29 matched control subjects (C) were analyzed. During the 24 hours before patch placement, pain scores and narcotic use were similar (LP 5.3, C 4.6, P = 0.19 and LP 51, C 32 mg morphine, P = 0.17). In the 24 hours after patch placement, LP patients had a greater decrease in pain scores (LP 1.2, C 0.0, P = 0.01) with no change in narcotic use (LP -8.4, C 0.5-mg change in morphine, P = 0.25). At 60 days, LP patients had a lower MPQ pain score (LP 7.7, C 12.2, P < 0.01), although only one patient was still using a patch. There was no difference in time to return to baseline activity (LP 73, C 105 days, P = 0.16) and no adverse events. Lidocaine patches are a safe, effective adjunct for rib fracture pain. Lidocaine patches resulted in a sustained reduction in pain, outlasting the duration of therapy.

Macronutrient balancing affects patch departure by guerezas (Colobus guereza).

PubMed

Johnson, Caley A; Raubenheimer, David; Chapman, Colin A; Tombak, Kaia J; Reid, Andrea J; Rothman, Jessica M

2017-04-01

Foraging strategies are central in shaping social structure and grouping patterns in primates. We address Colobus guereza foraging strategies by investigating their patch departure decisions in relation to diet composition and nutrition. We examine whether guerezas are constrained in their intake of food in patches and thereby forage according to a fixed amount strategy that dictates patch departure. Additionally, we assess whether guereza employ a fixed time strategy or attempt to balance nutrients when foraging. We measured food patch occupancy time, intake rates, and analyzed foods for macronutrients, fiber, and condensed tannins. We determined that guerezas do not employ a fixed time foraging strategy; patch residence time varied widely between 1 and 290 min. They also did not depart patches or stop eating when they reached a specific intake of dry mass, macronutrients, or condensed tannins. However, guerezas maintained a macronutrient balance when feeding across patches, and the balance of protein to non-protein energy (fats and carbohydrates) in patches is the best indicator of time adult guerezas spent feeding in patches. Previous studies have shown that the protein-to-fiber ratio is important in predicting food selection for folivores and their biomass; however, we found that guerezas did not maximize protein and minimize fiber intake while foraging in patches, nor did they stay longer in patches with the highest ratio of protein to fiber concentrations. This study raises questions about the nutritional and social implications of patch depletion as a foraging strategy in folivorous monkeys where food limitation predicts competitive and social regimes. Am. J. Primatol. 79:e22495, 2017. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Two-year follow-up of a randomized trial of spectacles plus alternate-day patching to treat strabismic amblyopia.

PubMed

Agervi, Pia; Kugelberg, Ulla; Kugelberg, Maria; Zetterström, Charlotta

2013-11-01

  To compare spectacles plus alternate-day patching for 8 hr or more with spectacles plus patching for 8 hr or more 6 days weekly to treat strabismic amblyopia 1 year after a 1-year randomized trial. Forty children (mean age, 4.3 years) participated. Refractive correction was provided. The children were assigned to alternate-day patching for 8 hr or more or patching for 8 hr or more daily 6 days weekly. VA, binocular function, and refractive errors were measured after 2 years. The main outcome measure was the median VA change in the amblyopic eye after 2 years. The median VA change in the amblyopic eye at the 2-year visit was significantly (p = 0.0453) greater with alternate-day patching (0.8 log unit) versus patching daily 6 days weekly (0.6 log unit). The final median VA in the amblyopic eyes was 0.0 logMAR in the alternate-day patching group and 0.1 logMAR in the daily patching group. Binocular function improved with both treatments. The median spherical equivalent (SE) refractive error increased in the fellow eyes (alternate-day patching, p < 0.0001; patching daily 6 days weekly, p = 0.0033); no change was found in the amblyopic eyes in either group. The magnitude of the VA change 2 years after treatment with spectacles plus alternate-day patching for 8 hr or more was significantly greater than with spectacles plus daily patching for 8 hr or more 6 days weekly for strabismic amblyopia. However, the final median VA did not differ significantly between the two treatments. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

Treatment of Neuropathic Pain with the Capsaicin 8% Patch: Is Pretreatment with Lidocaine Necessary?

PubMed Central

Kern, Kai-Uwe; Nowack, Walburga; Poole, Chris

2014-01-01

The capsaicin 8% patch can effectively treat neuropathic pain, but application can cause discomfort or a burning sensation. Until March 2013, it was recommended that patients be pretreated with a topical anesthetic, for example lidocaine, before capsaicin patch application. However, speculation existed over the need for pretreatment and its effectiveness in alleviating treatment-associated discomfort. This article compares tolerability to and efficacy of the capsaicin patch in pretreated and non-pretreated patients. All patients received a single capsaicin patch application. Pretreated patients received a lidocaine plaster before and intravenous lidocaine and metamizole infusions during capsaicin patch application. Pain levels, assessed using a Numeric Rating Scale (NRS), were used to determine tolerability and efficacy. All patients (pretreated n = 32; non-pretreated n = 26) completed 100% of the intended capsaicin patch application duration. At the time of capsaicin patch removal, 69% of pretreated and 88% of non-pretreated patients reported an NRS score increase, which returned to baseline by 6 hours post-treatment. There was no significant difference in mean NRS score between patient groups at any time during or after capsaicin patch treatment. Response was similar between patient groups; capsaicin patch treatment provided rapid and significant pain reductions that were sustained over 12 weeks. The same proportion of pretreated and non-pretreated patients reported willingness to receive retreatment with the capsaicin patch. This analysis shows that the capsaicin 8% patch is generally tolerable, and the small discomfort associated with patch application is short-lived. Lidocaine pretreatment does not have a significant effect on tolerability, efficacy, or patient willingness to receive retreatment. PMID:24289500

Coevolution of patch-type dependent emigration and patch-type dependent immigration.

PubMed

Weigang, Helene C

2017-08-07

The three phases of dispersal - emigration, transfer and immigration - are affecting each other and the former and latter decisions may depend on patch types. Despite the inevitable fact of the complexity of the dispersal process, patch-type dependencies of dispersal decisions modelled as emigration and immigration are usually missing in theoretical dispersal models. Here, I investigate the coevolution of patch-type dependent emigration and patch-type dependent immigration in an extended Hamilton-May model. The dispersing population inhabits a landscape structured into many patches of two types and disperses during a continuous-time season. The trait under consideration is a four dimensional vector consisting of two values for emigration probability from the patches and two values for immigration probability into the patches of each type. Using the adaptive dynamics approach I show that four qualitatively different dispersal strategies may evolve in different parameter regions, including a counterintuitive strategy, where patches of one type are fully dispersed from (emigration probability is one) but individuals nevertheless always immigrate into them during the dispersal season (immigration probability is one). I present examples of evolutionary branching in a wide parameter range, when the patches with high local death rate during the dispersal season guarantee a high expected disperser output. I find that two dispersal strategies can coexist after evolutionary branching: a strategy with full immigration only into the patches with high expected disperser output coexists with a strategy that immigrates into any patch. Stochastic simulations agree with the numerical predictions. Since evolutionary branching is also found when immigration evolves alone, the present study is adding coevolutionary constraints on the emigration traits and hence finds that the coevolution of a higher dimensional trait sometimes hinders evolutionary diversification. Copyright © 2017 Elsevier Ltd. All rights reserved.

Granisetron Transdermal Patch

MedlinePlus

... patch. Each patch is stuck onto a thin plastic liner and a separate rigid plastic film. Do not open the pouch in advance, ... cut the patch into pieces. Peel the thin plastic liner off of the printed side of the ...

Lidocaine Transdermal Patch

MedlinePlus

... It works by stopping nerves from sending pain signals. ... time and the length of time you may wear the patches. Never apply more than three patches at one time, and never wear patches for more than 12 hours per day. ...

Does switching contraceptive from oral to a patch or vaginal ring change the likelihood of timely prescription refill?

PubMed

Law, Amy; Lee, Yi-Chien; Gorritz, Magdaliz; Plouffe, Leo

2014-08-01

This study evaluated contraceptive refill patterns of women insured commercially in the US who switched from oral contraceptives (OCs) to the patch or vaginal ring and assessed if switching contraceptive methods changes refill patterns. Women aged 15-44 with ≥2 patch or ring prescriptions and ≥2 OC prescriptions before the first patch/ring prescription were identified from the MarketScan® Commercial database (1/1/2002-6/30/2011). Refill patterns 1-year pre- and postindex date (first patch/ring prescription) were evaluated, and women were categorized as timely or delayed refillers on OCs and patch/ring. Regression modeling was used to investigate the association between refill patterns and contraceptive methods and switching effects on refill patterns. Of 17,814 women identified, 7901 switched to the patch, and 9913 switched to the ring. Among timely OC refillers, the percentage of timely refills decreased (patch: 95.6% to 79.4%, p<.001; ring: 96.5% to 74.3%, p<.001). However, among delayed OC refillers, the percentage of timely refills improved (patch: 47.9% to 72.2%, p<.001; ring: 50.4% to 64.0%, p<.001) during patch/ring use. Nonetheless, compared to timely OC refillers, women who were delayed OC refillers had 1.68-fold [95% confidence interval (CI): 1.52-1.84, p<.001] and 1.85-fold greater odds (CI: 1.69-2.02, p<.001) of being a delayed refiller while on the patch and ring, respectively. Switching to the patch or ring may improve refill behavior for women who have problems refilling OCs timely; however, the magnitude of the improvement may fail to improve ultimate contraceptive efficacy by simply switching to the patch or ring. The impact on timely refills of switching from OCs to either the patch or ring is complex and varies depending on the pattern of timely refills on OCs. Copyright © 2014 Elsevier Inc. All rights reserved.

Heterogeneity of clonal patterns among patches of kudzu, Pueraria montana var. lobata, an invasive plant

PubMed Central

Kartzinel, Tyler R.; Hamrick, J. L.; Wang, Chongyun; Bowsher, Alan W.; Quigley, Bryan G. P.

2015-01-01

Background and Aims Viny species are among the most serious invasive plants, and better knowledge of how vines grow to dominate landscapes is needed. Patches may contain a single genotype (i.e. genet), a competitively dominant genet or many independent but interacting genets, yet the clonal structure of vining species is often not apparent. Molecular markers can discriminate among the genetic identities of entwined vines to reveal the number and spatial distribution of genets. This study investigated how genets are spatially distributed within and among discrete patches of the invasive vine kudzu, Pueraria montana var. lobata, in the United States. It was expected that ramets of genets would be spatially clustered within patches, and that an increase in the number of genets within a patch would be associated with a decrease in the average size of each genet. Methods Six discrete kudzu patches were sampled across 2 years, and 1257 samples were genotyped at 21 polymorphic allozyme loci. Variation in genotypic and genetic diversity among patches was quantified and patterns of genet interdigitation were analysed. Key Results Substantial genotypic and genetic variation occurred within and among patches. As few as ten overlapping genets spanned up to 68 m2 in one patch, while >90 % of samples were genetically unique in another patch. Genotypic diversity within patches increased as mean clone size decreased, although spatially widespread genets did not preclude interdigitation. Eight genets were shared across ≥2 patches, suggesting that vegetative dispersal can occur among patches. Conclusions Genetically unique kudzu vines are highly interdigitated. Multiple vegetative propagules have become established in spatially discrete patches, probably through the movement of highway construction or maintenance machinery. The results suggest that common methods for controlling invasive vines (e.g. mowing) may inadvertently increase genotypic diversity. Thus, understanding vine architecture and growth has practical implications. PMID:26229064

Effects of Intra- and Interpatch Host Density on Egg Parasitism by Three Species of Trichogramma

PubMed Central

Grieshop, Matthew J.; Flinn, Paul W.; Nechols, James R.

2010-01-01

Host-foraging responses to different intra- and interpatch densities were used to assess three Trichogramma spp. (Hymenoptera: Trichogrammatidae) Trichogramma deion Pinto and Oatman, T. ostriniae Pang and Chen, and T. pretiosum Riley — as potential biological control agents for the Indian meal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae). Single naïve females were allowed 6 h to forage in Plexiglas arenas with four different spatial arrangements of host eggs, nine single-egg patches), nine four-egg patches, 36 single-egg patches, and 36 four-egg patches. No significant differences were found among species in the number of patches parasitized. As expected, all three species parasitized the most eggs in the 36 four-egg patch treatment and the least in the nine single-egg patch treatment. T. deion parasitized significantly more eggs than T. pretiosum on the nine four-egg patches. T. ostriniae parasitized significantly more patches when intrapatch density was greater, regardless of interpatch density. In contrast, T. deion only parasitized more patches at the greater intrapatch density when the interpatch density was low. Patch density had no effect on T. pretiosum. The spatial pattern of parasitism was more aggregated for T. deion and T. ostriniae in the 36 four-egg patches treatment compared to the 36 single-egg patches treatment. Therefore, intrapatch density was more important than interpatch density for T. ostriniae, and potentially for T. deion, but not for T. pretiosum. T. deion may be the best candidate for augmentative biological control because it parasitized either slightly or significantly more eggs than the other two species in all four treatments. Furthermore, the pattern of parasitism by T. deion in the 36 four-egg patches treatment was the most aggregated among the three species, suggesting a more thorough searching pattern. In contrast, T. pretiosum had the least aggregated pattern of parasitism and therefore may have used a more random foraging pattern. PMID:20673123

Effects of intra- and interpatch host density on egg parasitism by three species of Trichogramma.

PubMed

Grieshop, Matthew J; Flinn, Paul W; Nechols, James R

2010-01-01

Host-foraging responses to different intra- and interpatch densities were used to assess three Trichogramma spp. (Hymenoptera: Trichogrammatidae) Trichogramma deion Pinto and Oatman, T. ostriniae Pang and Chen, and T. pretiosum Riley - as potential biological control agents for the Indian meal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae). Single naïve females were allowed 6 h to forage in Plexiglas arenas with four different spatial arrangements of host eggs, nine single-egg patches), nine four-egg patches, 36 single-egg patches, and 36 four-egg patches. No significant differences were found among species in the number of patches parasitized. As expected, all three species parasitized the most eggs in the 36 four-egg patch treatment and the least in the nine single-egg patch treatment. T. deion parasitized significantly more eggs than T. pretiosum on the nine four-egg patches. T. ostriniae parasitized significantly more patches when intrapatch density was greater, regardless of interpatch density. In contrast, T. deion only parasitized more patches at the greater intrapatch density when the interpatch density was low. Patch density had no effect on T. pretiosum. The spatial pattern of parasitism was more aggregated for T. deion and T. ostriniae in the 36 four-egg patches treatment compared to the 36 single-egg patches treatment. Therefore, intrapatch density was more important than interpatch density for T. ostriniae, and potentially for T. deion, but not for T. pretiosum. T. deion may be the best candidate for augmentative biological control because it parasitized either slightly or significantly more eggs than the other two species in all four treatments. Furthermore, the pattern of parasitism by T. deion in the 36 four-egg patches treatment was the most aggregated among the three species, suggesting a more thorough searching pattern. In contrast, T. pretiosum had the least aggregated pattern of parasitism and therefore may have used a more random foraging pattern.

Patch-based Convolutional Neural Network for Whole Slide Tissue Image Classification

PubMed Central

Hou, Le; Samaras, Dimitris; Kurc, Tahsin M.; Gao, Yi; Davis, James E.; Saltz, Joel H.

2016-01-01

Convolutional Neural Networks (CNN) are state-of-the-art models for many image classification tasks. However, to recognize cancer subtypes automatically, training a CNN on gigapixel resolution Whole Slide Tissue Images (WSI) is currently computationally impossible. The differentiation of cancer subtypes is based on cellular-level visual features observed on image patch scale. Therefore, we argue that in this situation, training a patch-level classifier on image patches will perform better than or similar to an image-level classifier. The challenge becomes how to intelligently combine patch-level classification results and model the fact that not all patches will be discriminative. We propose to train a decision fusion model to aggregate patch-level predictions given by patch-level CNNs, which to the best of our knowledge has not been shown before. Furthermore, we formulate a novel Expectation-Maximization (EM) based method that automatically locates discriminative patches robustly by utilizing the spatial relationships of patches. We apply our method to the classification of glioma and non-small-cell lung carcinoma cases into subtypes. The classification accuracy of our method is similar to the inter-observer agreement between pathologists. Although it is impossible to train CNNs on WSIs, we experimentally demonstrate using a comparable non-cancer dataset of smaller images that a patch-based CNN can outperform an image-based CNN. PMID:27795661

Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function

PubMed Central

Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

2016-01-01

In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, free-standing electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on-demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function. PMID:26974408

The use of epoxy patch grafts for the repair of experimentally-created diaphragmatic defects in dogs.

PubMed

Matsumoto, H; Oguchi, Y; Miyake, Y; Masuda, Y; Masada, S; Kuno, Y; Shibahara, I; Takashima, K; Yamane, H; Yamagata, S; Noishiki, Y; Yamane, Y

1996-07-01

Canine pericardium which had been treated with polyepoxy compounds (Denacol EX-313) was used as a patch graft for the correction of experimentally-created diaphragmatic defects in five dogs belonging to the same litter. Clinical, macroscopic and histological examinations were conducted every month up to five months after suturing of the patch graft. Clinical examination of the patch graft showed no apparent abnormalities. Macroscopic examination conducted during autopsy showed that the patch graft maintained adequate elasticity for five months after suturing, the surface of the patch graft was covered with a thin membrane and neovascularization was observed. Histological examination showed that the surface of the patch graft was covered with a thin membrane. Inflammatory tissue reactions were observed at one month, but gradually decreased from the second month onwards. In addition, the patch graft had excellent tissue affinity.

The modeling of piezoceramic patch interactions with shells, plates and beams

NASA Technical Reports Server (NTRS)

Banks, H. T.; Smith, R. C.

1992-01-01

General models describing the interactions between a pair of piezoceramic patches and elastic substructures consisting of a cylindrical shell, plate and beam are presented. In each case, the manner in which the patch loads enter both the strong and weak forms of the time-dependent structural equations of motion is described. Through force and moment balancing, these loads are then determined in terms of material properties of the patch and substructure (thickness, elastic properties, Poisson ratios), the geometry of the patch placement, and the voltages into the patches. In the case of the shell, the coupling between banding and inplane deformations, which is due to the curvature, is retained. These models are sufficiently general to allow for potentially different patch voltages which implies that they can be suitably employed when using piezoceramic patches for controlling system dynamics when both extensional and bending vibrations are present.

Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function.

PubMed

Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

2016-06-01

In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, freestanding electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function.

Density of Diadema antillarum (Echinodermata: Echinoidea) on live coral patch reefs and dead Acropora cervicornis rubble patches near Loggerhead Key, Dry Tortugas National Park, Florida, USA

EPA Science Inventory

Density of adult Diadema antillarum was assessed on live coral patch reefs and dead Acropora cervicornis rubble patches next to Loggerhead Key, Dry Tortugas National Park, Florida, USA in June 2009. Mean density on live coral patch reefs (0.49 individuals m-2) was not statistical...

Improved Gain Microstrip Patch Antenna

DTIC Science & Technology

2015-08-06

08-2015 Publication Improved Gain Microstrip Patch Antenna David A. Tonn Naval Under Warfare Center Division, Newport 1176 Howell St., Code 00L...GAIN MICROSTRIP PATCH ANTENNA STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and used by or for the...patch antenna having increased gain, and an apparatus for increasing the gain and bandwidth of an existing microstrip patch antenna . (2) Description

Buccal patches of atenolol formulated using fenugreek (Trigonella foenum-graecum L.) seed mucilage.

PubMed

Adhikari, Surya Narayan Ratha; Panda, Satyabrata

2017-01-01

The use of mucoadhesive natural polymers in designing mucoadhesive patch systems has received much attention. The study involved the development and evaluation of buccal patches of atenolol using fenugreek (Trigonella foenum-graecum L.) seed mucilage with hydroxylpropyl methyl cellulose (HPMC K4M) and a backing membrane (ethyl cellulose 5% w/v). These atenolol-releasing buccal patches were prepared using a solvent casting technique. The buccal patches prepared were evaluated for average weight, thickness, drug content, folding endurance and moisture content. Ex vivo mucoadhesive strength, force of adhesion and bonding strength were determined using porcine buccal mucosa. The mucosal permeation of atenolol through the porcine buccal mucosa was carried out using a Franz diffusion cell in phosphate buffer saline, pH 6.8. These buccal patches were also characterized by SEM and FTIR spectroscopy. The average weight, thickness, drug content, folding endurance and moisture content of these atenolol-releasing buccal patches were found satisfactory for all the patches. Amongst all, the F-4 buccal patch showed maximum mucoadhesive strength (31.12 ±1.86 g), force of adhesion (30.53 × 10-2 N) and bond strength (1748.89 N/m2). Ex vivo atenolol permeation from the buccal patches showed drug permeation across the excised porcine buccal mucosa over 12 h. The F-4 buccal patch showed maximum permeation flux (29.12 μg/cm2/h). The developed atenolol-releasing buccal patches can be beneficial over the conventional drug delivery systems to decrease the dosing frequency and enhance patient compliance.

Dye-enhanced protein solders and patches in laser-assisted tissue welding.

PubMed

Small, W; Heredia, N J; Maitland, D J; Da Silva, L B; Matthews, D L

1997-01-01

This study examines the use of dye-enhanced protein bonding agents in 805 nm diode laser-assisted tissue welding. A comparison of an albumin liquid solder and collagen solid-matrix patches used to repair arteriotomies in an in vitro porcine model is presented. Extrinsic bonding media in the form of solders and patches have been used to enhance the practice of laser tissue welding. Preferential absorption of the laser wavelength has been achieved by the incorporation of chromophores. Both the solder and the patch included indocyanine green dye (ICG) to absorb the 805 nm continuous-wave diode laser light used to perform the welds. Solder-mediated welds were divided into two groups (high power/short exposure and low power/long exposure), and the patches were divided into three thickness groups ranging from 0.1 to 1.3 mm. The power used to activate the patches was constant, but the exposure time was increased with patch thickness. Burst pressure results indicated that solder-mediated and patched welds yielded similar average burst strengths in most cases, but the patches provided a higher success rate (i.e., more often exceeded 150 mmHg) and were more consistent (i.e., smaller standard deviation) than the solder. The strongest welds were obtained using 1.0-1.3 mm thick patches, while the high power/short exposure solder group was the weakest. Though the solder and patches yielded similar acute weld strengths, the solid-matrix patches facilitated the welding process and provided consistently strong welds. The material properties of the extrinsic agents influenced their performance.

Does body size affect a bird's sensitivity to patch size and landscape structure?

USGS Publications Warehouse

Winter, Maiken; Johnson, Douglas H.; Shaffer, Jill A.

2006-01-01

Larger birds are generally more strongly affected by habitat loss and fragmentation than are smaller ones because they require more resources and thus larger habitat patches. Consequently, conservation actions often favor the creation or protection of larger over smaller patches. However, in grassland systems the boundaries between a patch and the surrounding landscape, and thus the perceived size of a patch, can be indistinct. We investigated whether eight grassland bird species with different body sizes perceived variation in patch size and landscape structure in a consistent manner. Data were collected from surveys conducted in 44 patches of northern tallgrass prairie during 1998–2001. The response to patch size was very similar among species regardless of body size (density was little affected by patch size), except in the Greater Prairie-Chicken (Tympanuchus cupido), which showed a threshold effect and was not found in patches smaller than 140 ha. In landscapes containing 0%–30% woody vegetation, smaller species responded more negatively to increases in the percentage of woody vegetation than larger species, but above an apparent threshold of 30%, larger species were not detected. Further analyses revealed that the observed variation in responses to patch size and landscape structure among species was not solely due to body size per se, but to other differences among species. These results indicate that a stringent application of concepts requiring larger habitat patches for larger species appears to limit the number of grassland habitats that can be protected and may not always be the most effective conservation strategy.

Resource availability, matrix quality, microclimate, and spatial pattern as predictors of patch use by the Karner blue butterfly

USGS Publications Warehouse

Grundel, R.; Pavlovic, N.B.

2007-01-01

Determination of which aspects of habitat quality and habitat spatial arrangement best account for variation in a species’ distribution can guide management for organisms such as the Karner blue butterfly (Lycaeides melissa samuelis), a federally endangered subspecies inhabiting savannas of Midwest and Eastern United States. We examined the extent to which three sets of predictors, (1) larval host plant (Lupinus perennis, wild lupine) availability, (2) characteristics of the matrix surrounding host plant patches, and (3) factors affecting a patch’s thermal environment, accounted for variation in lupine patch use by Karner blues at Indiana Dunes National Lakeshore, Indiana and Fort McCoy, Wisconsin, USA. Each predictor set accounted for 7–13% of variation in patch occupancy by Karner blues at both sites and in larval feeding activity among patches at Indiana Dunes. Patch area, an indicator of host plant availability, was an exception, accounting for 30% of variation in patch occupancy at Indiana Dunes. Spatially structured patterns of patch use across the landscape accounted for 9–16% of variation in patch use and explained more variation in larval feeding activity than did spatial autocorrelation between neighboring patches. Because of this broader spatial trend across sites, a given management action may be more effective in promoting patch use in some portions of the landscape than in others. Spatial trend, resource availability, matrix quality, and microclimate, in general, accounted for similar amounts of variation in patch use and each should be incorporated into habitat management planning for the Karner blue butterfly.

Predation-related odours reduce oviposition in a herbivorous mite.

PubMed

Choh, Yasuyuki; Uefune, Masayoshi; Takabayashi, Junji

2010-01-01

When adult females of the herbivorous mite, Tetranychus urticae, were exposed to the predatory mite, Phytoseiulus persimilis, they laid fewer eggs than females that had not been exposed to P. persimilis when transferred onto a new leaf patch. However, when T. urticae females were exposed to either products of P. persimilis or artificially damaged conspecific eggs on a leaf patch, the number of T. urticae eggs on a new leaf patch did not differ significantly from the control. The reduced oviposition was neither due to the feeding activity on the leaf patch with P. persimilis nor to that on the new leaf patch. There was also no significant difference between the number of T. urticae eggs produced on a new leaf patch following exposure to the odours of a neighbouring leaf patch where there had previously been either P. persimilis or T. urticae adults. However, female T. urticae that had been exposed to odours from neighbouring leaf patches on which both T. urticae and P. persimilis had been placed produced significantly fewer eggs on a new leaf patch than those that had not been exposed to such odours. Neither odours from neighbouring intact leaf patches on which T. urticae eggs were preyed on by P. persimilis, nor odours from a neighbouring Parafilm patch on which T. urticae was preyed on by P. persimilis affected the oviposition of T. urticae. These data suggest that the presence of T. urticae, P. persimilis and a leaf patch are needed for the emission of odours to reduce oviposition in T. urticae.

Transdermal patches: history, development and pharmacology.

PubMed

Pastore, Michael N; Kalia, Yogeshvar N; Horstmann, Michael; Roberts, Michael S

2015-05-01

Transdermal patches are now widely used as cosmetic, topical and transdermal delivery systems. These patches represent a key outcome from the growth in skin science, technology and expertise developed through trial and error, clinical observation and evidence-based studies that date back to the first existing human records. This review begins with the earliest topical therapies and traces topical delivery to the present-day transdermal patches, describing along the way the initial trials, devices and drug delivery systems that underpin current transdermal patches and their actives. This is followed by consideration of the evolution in the various patch designs and their limitations as well as requirements for actives to be used for transdermal delivery. The properties of and issues associated with the use of currently marketed products, such as variability, safety and regulatory aspects, are then described. The review concludes by examining future prospects for transdermal patches and drug delivery systems, such as the combination of active delivery systems with patches, minimally invasive microneedle patches and cutaneous solutions, including metered-dose systems. © 2015 The British Pharmacological Society.

Birth Control Patch

MedlinePlus

... Safe Videos for Educators Search English Español Birth Control Patch KidsHealth / For Teens / Birth Control Patch What's in this article? What Is It? ... It Cost? Print What Is It? The birth control patch is a thin, beige, 1¾-inch (4½- ...

Electrophysiological and Electrochemical Methods Development for the Detection of Biologically Active Chemical Agents

DTIC Science & Technology

1988-11-01

Bilayer ........................................... 14 5. Current-Voltage Curve for Gramacidin in a Lecithin -Sphingomyelin Patch Bilayer... lecithin (Avanti). 9 2. MATERIALS 2.1 Patch Microprobe Instrumentation. The basis of the microprobe system is an AxoPatch Patch- Clamping Amplifier System...histogram of 1024 events cut above 2 pA. Events sampled are thought to be from the same single gramacidin channel in a lecithin : sphingomyelin (5:1) patch

Patch Test Negative Generalized Dermatitis.

PubMed

Spiker, Alison; Mowad, Christen

2016-01-01

Allergic contact dermatitis is a common condition in dermatology. Patch testing is the criterion standard for diagnosis. However, dermatitis is not always caused by an allergen, and patch testing does not identify a culprit in every patient. Generalized dermatitis, defined as eczematous dermatitis affecting greater than 3 body sites, is often encountered in dermatology practice, especially patch test referral centers. Management for patients with generalized dermatitis who are patch test negative is challenging. The purpose of this article is to outline an approach to this challenging scenario and summarize the paucity of existing literature on patch test negative generalized dermatitis.

Good coupling for the multiscale patch scheme on systems with microscale heterogeneity

NASA Astrophysics Data System (ADS)

Bunder, J. E.; Roberts, A. J.; Kevrekidis, I. G.

2017-05-01

Computational simulation of microscale detailed systems is frequently only feasible over spatial domains much smaller than the macroscale of interest. The 'equation-free' methodology couples many small patches of microscale computations across space to empower efficient computational simulation over macroscale domains of interest. Motivated by molecular or agent simulations, we analyse the performance of various coupling schemes for patches when the microscale is inherently 'rough'. As a canonical problem in this universality class, we systematically analyse the case of heterogeneous diffusion on a lattice. Computer algebra explores how the dynamics of coupled patches predict the large scale emergent macroscale dynamics of the computational scheme. We determine good design for the coupling of patches by comparing the macroscale predictions from patch dynamics with the emergent macroscale on the entire domain, thus minimising the computational error of the multiscale modelling. The minimal error on the macroscale is obtained when the coupling utilises averaging regions which are between a third and a half of the patch. Moreover, when the symmetry of the inter-patch coupling matches that of the underlying microscale structure, patch dynamics predicts the desired macroscale dynamics to any specified order of error. The results confirm that the patch scheme is useful for macroscale computational simulation of a range of systems with microscale heterogeneity.

Intermediate disturbance in experimental landscapes improves persistence of beetle metapopulations.

PubMed

Govindan, Byju N; Feng, Zhilan; DeWoody, Yssa D; Swihart, Robert K

2015-03-01

Human-dominated landscapes often feature patches that fluctuate in suitability through space and time, but there is little experimental evidence relating the consequences of dynamic patches for species persistence. We used a spatially and temporally dynamic metapopulation model to assess and compare metapopulation capacity and persistence for red flour beetles (Tribolium castaneum) in experimental landscapes differentiated by resource structure, patch dynamics (destruction and restoration), and connectivity. High connectivity increased the colonization rate of beetles, but this effect was less pronounced in heterogeneous relative to homogeneous landscapes. Higher connectivity and faster patch dynamics increased extinction rates in landscapes. Lower connectivity promoted density-dependent emigration. Heterogeneous landscapes containing patches of different carrying capacity enhanced landscape-level occupancy probability. The highest metapopulation capacity and persistence was observed in landscapes with heterogeneous patches, low connectivity, and slow patch dynamics. Control landscapes with no patch dynamics exhibited rapid declines in abundance and approached extinction due to increased adult mortality in the matrix, higher pupal cannibalism by adults, and extremely low rates of exchange between remaining habitable patches. Our results highlight the role of intermediate patch dynamics, intermediate connectivity, and the nature of density dependence of emigration for persistence of species in heterogeneous landscapes. Our results also demonstrate the importance of incorporating local dynamics into the estimation of metapopulation capacity for conservation planning.

Correlation of open cell-attached and excised patch clamp techniques.

PubMed

Filipovic, D; Hayslett, J P

1995-11-01

The excised patch clamp configuration provides a unique technique for some types of single channel analyses, but maintenance of stable, long-lasting preparations may be confounded by rundown and/or rapid loss of seal. Studies were performed on the amiloride-sensitive Na+ channel, located on the apical surface of A6 cells, to determine whether the nystatin-induced open cell-attached patch could serve as an alternative configuration. Compared to excised inside-out patches, stable preparations were achieved more readily with the open cell-attached patch (9% vs. 56% of attempts). In both preparations, the current voltage (I-V) relation was linear, current amplitudes were equal at opposite equivalent clamped voltages, and Erev was zero in symmetrical Na+ solutions, indicating similar Na+ activities on the cytosolic and external surfaces of the patch. Moreover, there was no evidence that nystatin altered channel activity in the patch because slope conductance (3-4pS) and Erev (75 mV), when the bath was perfused with a high K:low Na solution (ENa = 80 mV), were nearly equal in both patch configurations. Our results therefore indicate that the nystatin-induced open cell-attached patch can serve as an alternative approach to the excised inside-out patch when experiments require modulation of univalent ions in the cytosol.

Single-Layer, All-Metal Patch Antenna Element with Wide Bandwidth

NASA Technical Reports Server (NTRS)

Chamberlain, Neil F.; Hodges, Richard E.; Zawardzki, Mark S.

2012-01-01

It is known that the impedance at the center of a patch antenna element is a short circuit, implying that a wire or post can be connected from the patch to the groundplane at this point without impacting radiation performance. In principle, this central post can be used to support the patch element, thus eliminating the need for dielectric. In spaceborne applications, this approach is problematic because a patch element supported by a single, thin post is highly susceptible to acoustic loads during launch. The technology reported here uses a large-diameter center post as its supporting structure. The supporting structure allows for the fabrication of a sufficiently rigid antenna element that can survive launch loads. The post may be either hollow or solid, depending on fabrication approach and/or mass constraints. The patch antenna element and support post are envisioned as being fabricated (milled) from a single piece of aluminum or other metal. Alternately, the patch plate and support column can be fabricated separately and then joined using fasteners, adhesive, or welding. Casting and electroforming are also viable techniques for manufacturing the metal patch part(s). The patch structure is then either bonded or fastened to the supporting groundplane. Arrays of patch elements can be fabricated by attaching several structures to a common groundplane/support structure.

The effects of facilitation and competition on group foraging in patches

PubMed Central

Laguë, Marysa; Tania, Nessy; Heath, Joel; Edelstein-Keshet, Leah

2012-01-01

Significant progress has been made towards understanding the social behaviour of animal groups, but the patch model, a foundation of foraging theory, has received little attention in a social context. The effect of competition on the optimal time to leave a foraging patch was considered as early as the original formulation of the marginal value theorem, but surprisingly, the role of facilitation (where foraging in groups decreases the time to find food in patches), has not been incorporated. Here we adapt the classic patch model to consider how the trade-off between facilitation and competition influence optimal group size. Using simple assumptions about the effect of group size on the food-finding time and the sharing of resources, we find conditions for existence of optima in patch residence time and in group size. When patches are close together (low travel times), larger group sizes are optimal. Groups are predicted to exploit patches differently than individual foragers and the degree of patch depletion at departure depends on the details of the trade-off between competition and facilitation. A variety of currencies and group-size effects are also considered and compared. Using our simple formulation, we also study the effects of social foraging on patch exploitation which to date have received little empirical study. PMID:22743132

The effects of facilitation and competition on group foraging in patches.

PubMed

Laguë, Marysa; Tania, Nessy; Heath, Joel; Edelstein-Keshet, Leah

2012-10-07

Significant progress has been made towards understanding the social behaviour of animal groups, but the patch model, a foundation of foraging theory, has received little attention in a social context. The effect of competition on the optimal time to leave a foraging patch was considered as early as the original formulation of the marginal value theorem, but surprisingly, the role of facilitation (where foraging in groups decreases the time to find food in patches), has not been incorporated. Here we adapt the classic patch model to consider how the trade-off between facilitation and competition influences optimal group size. Using simple assumptions about the effect of group size on the food-finding time and the sharing of resources, we find conditions for existence of optima in patch residence time and in group size. When patches are close together (low travel times), larger group sizes are optimal. Groups are predicted to exploit patches differently than individual foragers and the degree of patch depletion at departure depends on the details of the trade-off between competition and facilitation. A variety of currencies and group-size effects are also considered and compared. Using our simple formulation, we also study the effects of social foraging on patch exploitation which to date have received little empirical study. Copyright © 2012 Elsevier Ltd. All rights reserved.

Implantation of a cone-shaped double-fixed patch increases abdominal space and prevents recurrence of large defects in congenital diaphragmatic hernia.

PubMed

Loff, Steffan; Wirth, Hartmut; Jester, Iwgo; Hosie, Stuart; Wollmann, Carmen; Schaible, Thomas; Ataman, Ozge; Waag, Karl-Ludwig

2005-11-01

Large defects in patients with congenital diaphragmatic hernia (CDH) are frequently closed with a polytetrafluoroethylene patch (PTFE). Intraoperative problems include lack of abdominal domain for the reduction of organs and closure of the abdominal wall. Main surgical postoperative complication is the recurrence of the hernia. We suggest a new and easy method of patch implantation, improving these problems, and report first follow-up results. In our clinic, 103 children with CDH were treated, and 87 children underwent reconstruction of the diaphragm in the 5 years between 1998 and 2002. In 52 patients, a patch implantation had to be performed. We have been optimizing our complete pediatric and surgical procedure and present a new standardized technique of preparation and implantation of a PTFE patch. The flat patch is folded to a 90 degrees cone. The cone is fixed in its form with few single stitches. It is implanted with an overlapping border of 1 cm circumferentially. The border is separately fixed with absorbable single stitches to keep from rolling up. The rough side of the patch points toward the rim of the diaphragm to enable ingrowth of the connective tissue. In a 1-year follow-up study, the recurrences in the 3 following groups of PTFE patches were studied: conventional implantation (simple patch without overlapping border), patch with separately fixed overlapping border, and cone-shaped patch with overlapping separately fixed border. Thirty-three patients were included in the study. After conventional PTFE-patch implantation, 6 (46%) of 13 patients developed reherniation. After PTFE-patch implantation with separately fixed overlapping border, 1 (11%) of 9 patients had a recurrent hernia. In the group with the PTFE-cone implantation, 1 (9%) of 11 patients developed a recurrence. Meanwhile, another 20 CDH patients received implantation of a cone-shaped patch, and no further recurrence occurred up to now. With the additional space (20 mL) provided by the cone-shaped patch, the closure of the abdomen was easier, and the fundus had intraoperatively a physiological position. This optimized patch implantation technique in large diaphragmatic defects offers considerable advantages especially regarding recurrence of the hernia and closure of the abdomen, which are currently the most challenging surgical problems. 1. The cone-shaped 3-dimensional patch increases abdominal capacity. 2. Redundant chest capacity is reduced, and the reconstructed diaphragm shows a physiological shape. 3. The dome of the patch allows a physiological position of the gastric fundus and a normal Hiss angle, thus preventing gastroesophageal reflux. 4. Additional safety of the implantation is achieved by separate fixation of the overlapping border of the cone, preventing recurrence.

Evaluation of canine adverse food reactions by patch testing with single proteins, single carbohydrates and commercial foods.

PubMed

Johansen, Cornelia; Mariani, Claire; Mueller, Ralf S

2017-10-01

Adverse food reaction (AFR) is an important differential diagnosis for the pruritic dog. It is usually diagnosed by feeding an elimination diet with a novel protein and carbohydrate source for eight weeks followed by subsequent food provocation. A previous study demonstrated that patch testing dogs with foods had a high sensitivity and negative predictability for selection of elimination diet ingredients. The aim of this study was to investigate patch testing with proteins, carbohydrates and dry commercial dog food in dogs to determine whether there was value in patch testing to aid the diagnosis of canine adverse food reaction. Twenty five privately owned dogs, with confirmed AFR, underwent provocation trials with selected food antigens and patch testing. For proteins, carbohydrates and dry dog food the sensitivity of patch testing was 100%, 70% and 22.2%, respectively; the negative predictive values of patch testing were 100%, 79% and 72%. The positive predictive values of patch testing for proteins and carbohydrates were 75% and 74%, respectively. This study confirmed that patch testing may be useful for the selection of a suitable protein source for an elimination diet in dogs with suspected AFR, but not as a diagnostic tool for canine AFR. Results for proteins are more reliable than for carbohydrates and the majority of positive patch test reactions were observed with raw protein. Patch testing with commercial dog food does not seem to be useful. © 2017 ESVD and ACVD.

Spatial layout affects speed discrimination

NASA Technical Reports Server (NTRS)

Verghese, P.; Stone, L. S.

1997-01-01

We address a surprising result in a previous study of speed discrimination with multiple moving gratings: discrimination thresholds decreased when the number of stimuli was increased, but remained unchanged when the area of a single stimulus was increased [Verghese & Stone (1995). Vision Research, 35, 2811-2823]. In this study, we manipulated the spatial- and phase relationship between multiple grating patches to determine their effect on speed discrimination thresholds. In a fusion experiment, we merged multiple stimulus patches, in stages, into a single patch. Thresholds increased as the patches were brought closer and their phase relationship was adjusted to be consistent with a single patch. Thresholds increased further still as these patches were fused into a single patch. In a fission experiment, we divided a single large patch into multiple patches by superimposing a cross with luminance equal to that of the background. Thresholds decreased as the large patch was divided into quadrants and decreased further as the quadrants were maximally separated. However, when the cross luminance was darker than the background, it was perceived as an occluder and thresholds, on average, were unchanged from that for the single large patch. A control experiment shows that the observed trend in discrimination thresholds is not due to the differences in perceived speed of the stimuli. These results suggest that the parsing of the visual image into entities affects the combination of speed information across space, and that each discrete entity effectively provides a single independent estimate of speed.

The effects of platelet lysate patches on the activity of tendon-derived cells.

PubMed

Costa-Almeida, Raquel; Franco, Albina R; Pesqueira, Tamagno; Oliveira, Mariana B; Babo, Pedro S; Leonor, Isabel B; Mano, João F; Reis, Rui L; Gomes, Manuela E

2018-03-01

Platelet-derived biomaterials are widely explored as cost-effective sources of therapeutic factors, holding a strong potential for endogenous regenerative medicine. Particularly for tendon repair, treatment approaches that shift the injury environment are explored to accelerate tendon regeneration. Herein, genipin-crosslinked platelet lysate (PL) patches are proposed for the delivery of human-derived therapeutic factors in patch augmentation strategies aiming at tendon repair. Developed PL patches exhibited a controlled release profile of PL proteins, including bFGF and PDGF-BB. Additionally, PL patches exhibited an antibacterial effect by preventing the adhesion, proliferation and biofilm formation by S. aureus, a common pathogen in orthopaedic surgical site infections. Furthermore, these patches supported the activity of human tendon-derived cells (hTDCs). Cells were able to proliferate over time and an up-regulation of tenogenic genes (SCX, COL1A1 and TNC) was observed, suggesting that PL patches may modify the behavior of hTDCs. Accordingly, hTDCs deposited tendon-related extracellular matrix proteins, namely collagen type I and tenascin C. In summary, PL patches can act as a reservoir of biomolecules derived from PL and support the activity of native tendon cells, being proposed as bioinstructive patches for tendon regeneration. Platelet-derived biomaterials hold great interest for the delivery of therapeutic factors for applications in endogenous regenerative medicine. In the particular case of tendon repair, patch augmentation strategies aiming at shifting the injury environment are explored to improve tendon regeneration. In this study, PL patches were developed with remarkable features, including the controlled release of growth factors and antibacterial efficacy. Remarkably, PL patches supported the activity of native tendon cells by up-regulating tenogenic genes and enabling the deposition of ECM proteins. This patch holds great potential towards simultaneously reducing post-implantation surgical site infections and promoting tendon regeneration for prospective in vivo applications. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

"Phase capture" in amblyopia: the influence function for sampled shape.

PubMed

Levi, Dennis M; Li, Roger W; Klein, Stanley A

2005-06-01

This study was concerned with what stimulus information humans with amblyopia use to judge the shape of simple objects. We used a string of four Gabor patches to define a contour. A fifth, center patch served as the test pattern. The observers' task was to judge the location of the test pattern relative to the contour. The contour was either a straight line, or an arc with positive or negative curvature. We asked whether phase shifts in the inner or outer pairs of patches distributed along the contour influence the perceived shape. That is, we measured the phase shift influence function. Our results, consistent with previous studies, show that amblyopes are imprecise in shape discrimination, showing elevated thresholds for both lines and curves. We found that amblyopes often make much larger perceptual errors (biases) than do normal observers in the absence of phase shifts. These errors tend to be largest for curved shapes and at large separations. In normal observers, shifting the phase of inner patches of the string by 0.25 cycle results in almost complete phase capture (attraction) at the smallest separation (2 lambda), and the capture effect falls off rapidly with separation. A 0.25 cycle shift of the outer pair of patches has a much smaller effect, in the opposite direction (repulsion). While several amblyopic observers showed reduced capture by the phase of the inner patches, to our surprise, several of the amblyopes were sensitive to the phase of the outer patches. We used linear multiple regression to determine the weights of all cues to the task: the carrier phase of the inner patches, carrier phase of the outer patches and the envelope of the outer patches. Compared to normal observers, some amblyopes show a weaker influence of the phase of the inner patches, and a stronger influence of both the phase and envelope of the outer patches. We speculate that this may be a consequence of abnormal "crowding" of the inner patches by the outer ones.

Robust multi-atlas label propagation by deep sparse representation

PubMed Central

Zu, Chen; Wang, Zhengxia; Zhang, Daoqiang; Liang, Peipeng; Shi, Yonghong; Shen, Dinggang; Wu, Guorong

2016-01-01

Recently, multi-atlas patch-based label fusion has achieved many successes in medical imaging area. The basic assumption in the current state-of-the-art approaches is that the image patch at the target image point can be represented by a patch dictionary consisting of atlas patches from registered atlas images. Therefore, the label at the target image point can be determined by fusing labels of atlas image patches with similar anatomical structures. However, such assumption on image patch representation does not always hold in label fusion since (1) the image content within the patch may be corrupted due to noise and artifact; and (2) the distribution of morphometric patterns among atlas patches might be unbalanced such that the majority patterns can dominate label fusion result over other minority patterns. The violation of the above basic assumptions could significantly undermine the label fusion accuracy. To overcome these issues, we first consider forming label-specific group for the atlas patches with the same label. Then, we alter the conventional flat and shallow dictionary to a deep multi-layer structure, where the top layer (label-specific dictionaries) consists of groups of representative atlas patches and the subsequent layers (residual dictionaries) hierarchically encode the patchwise residual information in different scales. Thus, the label fusion follows the representation consensus across representative dictionaries. However, the representation of target patch in each group is iteratively optimized by using the representative atlas patches in each label-specific dictionary exclusively to match the principal patterns and also using all residual patterns across groups collaboratively to overcome the issue that some groups might be absent of certain variation patterns presented in the target image patch. Promising segmentation results have been achieved in labeling hippocampus on ADNI dataset, as well as basal ganglia and brainstem structures, compared to other counterpart label fusion methods. PMID:27942077

Comparison between over-glasses patching and adhesive patching for children with moderate amblyopia: a prospective randomized clinical trial.

PubMed

Kim, Su Jin; Jeon, Hyeshin; Jung, Jae Ho; Lee, Kwang Min; Choi, Hee Young

2018-02-01

To investigate efficacy of over-glasses patching treatment for amblyopic children using visual function improvement and Amblyopia Treatment Index (ATI) changes. In a randomized multi-center controlled clinical trial, 107 children aged 3-7 years with moderate amblyopia (visual acuity in the range of 20/40 to 20/100) were included to receive treatment with either an adhesive skin patch or a fabric over-glasses patch. The patients were prescribed 2 h of patching per day for the sound eye. Best-corrected visual acuity (BCVA) was investigated and ATI questionnaires were collected from parents at 5 weeks and 17 weeks after the initiation of treatment. ATI identifies barriers and problems associated with amblyopia treatment. We compared the changes of visual acuity of amblyopic eyes and ATI scores in two groups. At 17 weeks, the mean visual acuity of the amblyopic eye using Snellen chart improved 3.2 lines in the adhesive patching group and 2.7 lines for an over-glasses patching method that fit over eyeglasses (p = 0.345). A similar proportion of subjects in each group had improvement of ≥ 2 lines (adhesive patching group 67% vs over-glasses patching group 67%, p = 0.372). There was also no difference in treatment burden in each group as measured with the Amblyopia Treatment Index. The only item to demonstrate a significant difference between groups was that related to "Treatment makes the eye or eyelids red" (mean 4.0 ± 1.1 vs 3.0 ± 1.0 at 17 weeks, p = 0.001, for adhesive vs over-glasses patch). Over-glasses patching treatment is a useful option for amblyopia treatment when the patients suffer from adverse effects of using adhesive skin patching.

Robust multi-atlas label propagation by deep sparse representation.

PubMed

Zu, Chen; Wang, Zhengxia; Zhang, Daoqiang; Liang, Peipeng; Shi, Yonghong; Shen, Dinggang; Wu, Guorong

2017-03-01

Recently, multi-atlas patch-based label fusion has achieved many successes in medical imaging area. The basic assumption in the current state-of-the-art approaches is that the image patch at the target image point can be represented by a patch dictionary consisting of atlas patches from registered atlas images. Therefore, the label at the target image point can be determined by fusing labels of atlas image patches with similar anatomical structures. However, such assumption on image patch representation does not always hold in label fusion since (1) the image content within the patch may be corrupted due to noise and artifact; and (2) the distribution of morphometric patterns among atlas patches might be unbalanced such that the majority patterns can dominate label fusion result over other minority patterns. The violation of the above basic assumptions could significantly undermine the label fusion accuracy. To overcome these issues, we first consider forming label-specific group for the atlas patches with the same label. Then, we alter the conventional flat and shallow dictionary to a deep multi-layer structure, where the top layer ( label-specific dictionaries ) consists of groups of representative atlas patches and the subsequent layers ( residual dictionaries ) hierarchically encode the patchwise residual information in different scales. Thus, the label fusion follows the representation consensus across representative dictionaries. However, the representation of target patch in each group is iteratively optimized by using the representative atlas patches in each label-specific dictionary exclusively to match the principal patterns and also using all residual patterns across groups collaboratively to overcome the issue that some groups might be absent of certain variation patterns presented in the target image patch. Promising segmentation results have been achieved in labeling hippocampus on ADNI dataset, as well as basal ganglia and brainstem structures, compared to other counterpart label fusion methods.

Corridors and some ecological and evolutionary consequences of connectivity.

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

Orrock, John L

2004-07-01

Abstract - By connecting disjunct patches, corridors may offset the effects of fragmentation by promoting gene flow and population persistence. However, the ultimate effect of corridors on a focal species may hinge upon two considerations: how corridors may affect ecological interactions that impinge upon that species, and how corridors might affect the fixation of novel alleles that ultimately determine fitness and persistence. Using an experimental landscape, I show that corridor-mediated changes in patch shape change seed predation in connected and unconnected patches, and shift the behavior, abundance, and distribution of seed predators. Rodent seed predators removed more seeds in connectedmore » patches, arthropod seed predators removed more seeds in rectangular patches, and avian seed predation did not differ due to patch type. Rodent foraging was greater in the interior of connected patches because changes in patch shape influenced risk perceived by rodents while foraging. Ant communities were also affected by changes in patch shape caused by corridors, rather than corridor effects per se. The distribution and abundance of ants differed among edge-rich areas (corridors and wings), edges, and the patch interior. In rectangular patches, fire ants (Solenopsis spp.) had negative impacts on other ant species. By changing the activity of rodents, and the composition of ant communities, corridors may have important impacts on seeds. Bird-dispersed seeds may benefit from increased dispersal among connected patches, but connected patches also have greater predation risk. Using a simulation model, I demonstrate that gene flow between a stable population and a population that experiences local extinction or a reduction in size (e.g. due to natural or anthropogenic disturbance) can dramatically affect fixation of alleles in the stable population. Alone or in concert, frequent disturbance, high rates of movement, and low habitat quality make it more likely that connectivity-mediated fixation will promote fixation of harmful alleles and reduce fixation of beneficial alleles.« less

A simple technique for transferring excised patches of membrane to different solutions for single channel measurements.

PubMed

Quartararo, N; Barry, P H

1987-12-01

A technical problem associated with the patch clamp technique has been the changing of solutions bathing the membrane patch. The simple technique described here solves this problem by means of a movable polythene sleeve placed on the shaft of the patch clamp pipette. The sleeve is initially placed so that the tip of the pipette is exposed. A gigaohm seal is formed using standard techniques. The patch is then excised and the sleeve is slipped down a few mm past the end of the tip of the pipette. When the pipette and sleeve is now removed from the solution, a small drop of solution covering the membrane patch is held in place at the end of the sleeve by surface tension. The pipette is then easily transferred to a different solution without passing the membrane patch through the air-water interface. The sleeve is then simply pulled back up the pipette shaft to expose the membrane patch to the new solution.

Taro corms mucilage/HPMC based transdermal patch: an efficient device for delivery of diltiazem hydrochloride.

PubMed

Sarkar, Gunjan; Saha, Nayan Ranjan; Roy, Indranil; Bhattacharyya, Amartya; Bose, Madhura; Mishra, Roshnara; Rana, Dipak; Bhattacharjee, Debashis; Chattopadhyay, Dipankar

2014-05-01

The aim of this work is to examine the effectiveness of mucilage/hydroxypropylmethylcellulose (HPMC) based transdermal patch (matrix type) as a drug delivery device. We have successfully extracted mucilage from Colocasia esculenta (Taro) corms and prepared diltiazem hydrochloride incorporated mucilage/HPMC based transdermal patches using various wt% of mucilage by the solvent evaporation technique. Characterization of both mucilage and transdermal patches has been done by several techniques such as Molisch's test, organoleptic evaluation of mucilage, mechanical, morphological and thermal analysis of transdermal patches. Skin irritation test is studied on hairless Albino rat skin showing that transdermal patches are apparently free of potentially hazardous skin irritation. Fourier transform infrared analysis shows that there is no interaction between drug, mucilage and HPMC while scanning electron microscopy shows the surface morphology of transdermal patches. In vitro drug release time of mucilage-HPMC based transdermal patches is prolonged with increasing mucilage concentration in the formulation. Copyright © 2014 Elsevier B.V. All rights reserved.

Industrializing electrophysiology: HT automated patch clamp on SyncroPatch® 96 using instant frozen cells.

PubMed

Polonchuk, Liudmila

2014-01-01

Patch-clamping is a powerful technique for investigating the ion channel function and regulation. However, its low throughput hampered profiling of large compound series in early drug development. Fortunately, automation has revolutionized the area of experimental electrophysiology over the past decade. Whereas the first automated patch-clamp instruments using the planar patch-clamp technology demonstrated rather a moderate throughput, few second-generation automated platforms recently launched by various companies have significantly increased ability to form a high number of high-resistance seals. Among them is SyncroPatch(®) 96 (Nanion Technologies GmbH, Munich, Germany), a fully automated giga-seal patch-clamp system with the highest throughput on the market. By recording from up to 96 cells simultaneously, the SyncroPatch(®) 96 allows to substantially increase throughput without compromising data quality. This chapter describes features of the innovative automated electrophysiology system and protocols used for a successful transfer of the established hERG assay to this high-throughput automated platform.

An Electronic Patch for wearable health monitoring by reflectance pulse oximetry.

PubMed

Haahr, Rasmus G; Duun, Sune B; Toft, Mette H; Belhage, Bo; Larsen, Jan; Birkelund, Karen; Thomsen, Erik V

2012-02-01

We report the development of an Electronic Patch for wearable health monitoring. The Electronic Patch is a new health monitoring system incorporating biomedical sensors, microelectronics, radio frequency (RF) communication, and a battery embedded in a 3-dimensional hydrocolloid polymer. In this paper the Electronic Patch is demonstrated with a new optical biomedical sensor for reflectance pulse oximetry so that the Electronic Patch in this case can measure the pulse and the oxygen saturation. The reflectance pulse oximetry solution is based on a recently developed annular backside silicon photodiode to enable low power consumption by the light emitting components. The Electronic Patch has a disposable part of soft adhesive hydrocolloid polymer and a reusable part of hard polylaurinlactam. The disposable part contains the battery. The reusable part contains the reflectance pulse oximetry sensor and microelectronics. The reusable part is 'clicked' into the disposable part when the patch is prepared for use. The patch has a size of 88 mm by 60 mm and a thickness of 5 mm.

Lipid-glass adhesion in giga-sealed patch-clamped membranes.

PubMed

Opsahl, L R; Webb, W W

1994-01-01

Adhesion between patch-clamped lipid membranes and glass micropipettes is measured by high contrast video imaging of the mechanical response to the application of suction pressure across the patch. The free patch of membrane reversibly alters both its contact angle and radius of curvature on pressure changes. The assumption that an adhesive force between the membrane and the pipette can sustain normal tension up to a maximum Ta at the edge of the free patch accounts for the observed mechanical responses. When the normal component of the pressure-induced membrane tension exceeds Ta membrane at the contact point between the free patch and the lipid-glass interface is pulled away from the pipette wall, resulting in a decreased radius of curvature for the patch and an increased contact angle. Measurements of the membrane radius of curvature as a function of the suction pressure and pipette radius determine line adhesion tensions Ta which range from 0.5 to 4.0 dyn/cm. Similar behavior of patch-clamped cell membranes implies similar adhesion mechanics.

Comparison of Collagen Graft Fixation Methods in the Porcine Knee: Implications for Matrix-Assisted Chondrocyte Implantation and Second-Generation Autologous Chondrocyte Implantation.

PubMed

Whyte, Graeme P; McGee, Alan; Jazrawi, Laith; Meislin, Robert

2016-05-01

To evaluate the fixation integrity at time zero of a type I/III collagen patch secured to a chondral defect in the porcine knee using methods typically employed in autologous chondrocyte implantation (ACI) and matrix-assisted chondrocyte implantation. Twenty-four porcine knee specimens underwent a medial parapatellar arthrotomy. A prefabricated template was used to create cartilage defects of 2 cm(2) in the medial femoral condyle. A size-matched collagen patch was fashioned. Four methods of fixation to the chondral defect were analyzed: group 1-saline, group 2-fibrin glue around the periphery of the patch, group 3-fibrin glue applied to the base of the defect and around the periphery of the patch, group 4-6-0 vicryl suture and fibrin glue around the periphery of the patch. Collagen patch fixation was assessed at intervals of 60, 300, 600, 900, and 1,200 cycles from full extension to 90° of flexion, performed manually without application of axial force. Patch fixation was evaluated by 2 independent observers using a customized scoring scale. Mean peripheral detachment of the patch and chondral defect uncovering remained less than 25% for all groups. Area of defect uncovering was significantly increased in group 2 compared with group 4 after 900 and 1,200 cycles (P = .0014 and P = .0025, respectively). Fibrin glue applied to the base of the defect, or suturing of the patch, reduced deformation significantly after 900 cycles. Suture increases the stability of fixation of a type I/III collagen patch to a chondral defect better than fibrin glue alone in the porcine knee after repetitive cycling, with respect to patch detachment and chondral defect uncovering. Application of fibrin glue to the base of the defect, or securing the patch with suture, decreases collagen patch deformation. In cases where minimally invasive techniques do not allow suture fixation of the collagen patch, scaffold fixation may be compromised during articular motion protocols typically used after second- and third-generation ACI procedures. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Quantifying the importance of patch-specific changes in habitat to metapopulation viability of an endangered songbird.

PubMed

Horne, Jon S; Strickler, Katherine M; Alldredge, Mathew

2011-10-01

A growing number of programs seek to facilitate species conservation using incentive-based mechanisms. Recently, a market-based incentive program for the federally endangered Golden-cheeked Warbler (Dendroica chrysoparia) was implemented on a trial basis at Fort Hood, an Army training post in Texas, USA. Under this program, recovery credits accumulated by Fort Hood through contracts with private landowners are used to offset unintentional loss of breeding habitat of Golden-cheeked Warblers within the installation. Critical to successful implementation of such programs is the ability to value, in terms of changes to overall species viability, both habitat loss and habitat restoration or protection. In this study, we sought to answer two fundamental questions: Given the same amount of change in breeding habitat, does the change in some patches have a greater effect on metapopulation persistence than others? And if so, can characteristics of a patch (e.g., size or spatial location) be used to predict how the metapopulation will respond to these changes? To answer these questions, we describe an approach for using sensitivity analysis of a metapopulation projection model to predict how changes to specific habitat patches would affect species viability. We used a stochastic, discrete-time projection model based on stage-specific estimates of survival and fecundity, as well as various assumptions about dispersal among populations. To assess a particular patch's leverage, we quantified how much metapopulation viability was expected to change in response to changing the size of that patch. We then related original patch size and distance from the largest patch to each patch's leverage to determine if general patch characteristics could be used to develop guidelines for valuing changes to patches within a metapopulation. We found that both the characteristic that best predicted patch leverage and the magnitude of the relationship changed under different model scenarios. Thus, we were unable to find a consistent set of relationships, and therefore we emphasize the dangers in relying on general guidelines to assess patch value. Instead, we provide an approach that can be used to quantitatively evaluate patch value and identify critical needs for future research.

Movement of foraging Tundra Swans explained by spatial pattern in cryptic food densities.

PubMed

Klaassen, Raymond H G; Nolet, Bart A; Bankert, Daniëlle

2006-09-01

We tested whether Tundra Swans use information on the spatial distribution of cryptic food items (below ground Sago pondweed tubers) to shape their movement paths. In a continuous environment, swans create their own food patches by digging craters, which they exploit in several feeding bouts. Series of short (<1 m) intra-patch movements alternate with longer inter-patch movements (>1 m). Tuber biomass densities showed a positive spatial auto-correlation at a short distance (<3 m), but not at a larger distance (3-8 m). Based on the spatial pattern of the food distribution (which is assumed to be pre-harvest information for the swan) and the energy costs and benefits for different food densities at various distances, we calculated the optimal length of an inter-patch movement. A swan that moves to the patch with the highest gain rate was predicted to move to the adjacent patch (at 1 m) if the food density in the current patch had been high (>25 g/m2) and to a more distant patch (at 7-8 m) if the food density in the current patch had been low (<25 g/m2). This prediction was tested by measuring the response of swans to manipulated tuber densities. In accordance with our predictions, swans moved a long distance (>3 m) from a low-density patch and a short distance (<3 m) from a high-density patch. The quantitative agreement between prediction and observation was greater for swans feeding in pairs than for solitary swans. The result of this movement strategy is that swans visit high-density patches at a higher frequency than on offer and, consequently, achieve a 38% higher long-term gain rate. Swans also take advantage of spatial variance in food abundance by regulating the time in patches, staying longer and consuming more food from rich than from poor patches. We can conclude that the shape of the foraging path is a reflection of the spatial pattern in the distribution of tuber densities and can be understood from an optimal foraging perspective.

Habitat corridors function as both drift fences and movement conduits for dispersing flies.

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

Fried, Joanna H.; Levey Douglas J.; Hogsette, Jerome A.

2005-03-30

Abstract Corridors connect otherwise isolated habitat patches and can direct movement of animals among such patches. In eight experimental landscapes, we tested two hypotheses of how corridors might affect dispersal behavior. The Traditional Corridor hypothesis posits that animals preferentially leave patches via corridors, following them into adjacent patches. The Drift Fence hypothesis posits that animals dispersing through matrix habitat are diverted into patches with corridors because they follow corridors when encountered. House flies (Musca domestica L.), a species that prefers the habitat of our patches and corridors, were released in a central patch (100•100 m) and recaptured in peripheral patchesmore » that were or were not connected by a corridor. Flies were captured more frequently in connected than unconnected patches, thereby supporting the Traditional Corridor hypothesis. The Drift Fence hypothesis was also supported, as flies were captured more frequently in unconnected patches with blind (dead end) corridors than in unconnected patches of equal area without blind corridors. A second experiment tested whether these results might be dependent on the type of patch-matrix boundary encountered by dispersing flies and whether edge-following behavior might be the mechanism underlying the observed corridor effect in the first experiment. We recorded dispersal patterns of flies released along forest edges with dense undergrowth in the forest (‘‘closed’’ edges) and along edges with little forest understory (‘‘open’’ edges). Flies were less likely to cross and more likely to follow closed edges than open edges, indicating that when patch and corridor edges are pronounced, edge-following behavior of flies may direct them along corridors into connected patches. Because edges in the first experiment were open, these results also suggest that corridor effects for flies in that experiment would have been even stronger if the edges around the source patches and corridors had been more closed. Taken together, our results suggest that corridors can affect dispersal of organisms in unappreciated ways (i.e., as drift fences) and that edge type can alter dispersal behavior.« less

Reducible dictionaries for single image super-resolution based on patch matching and mean shifting

NASA Astrophysics Data System (ADS)

Rasti, Pejman; Nasrollahi, Kamal; Orlova, Olga; Tamberg, Gert; Moeslund, Thomas B.; Anbarjafari, Gholamreza

2017-03-01

A single-image super-resolution (SR) method is proposed. The proposed method uses a generated dictionary from pairs of high resolution (HR) images and their corresponding low resolution (LR) representations. First, HR images and the corresponding LR ones are divided into patches of HR and LR, respectively, and then they are collected into separate dictionaries. Afterward, when performing SR, the distance between every patch of the input LR image and those of available LR patches in the LR dictionary is calculated. The minimum distance between the input LR patch and those in the LR dictionary is taken, and its counterpart from the HR dictionary is passed through an illumination enhancement process. By this technique, the noticeable change of illumination between neighbor patches in the super-resolved image is significantly reduced. The enhanced HR patch represents the HR patch of the super-resolved image. Finally, to remove the blocking effect caused by merging the patches, an average of the obtained HR image and the interpolated image obtained using bicubic interpolation is calculated. The quantitative and qualitative analyses show the superiority of the proposed technique over the conventional and state-of-art methods.

Pathogen transmission at stage-structured infectious patches: Killers and vaccinators.

PubMed

Caraco, Thomas; Turner, Wendy C

2018-01-07

Spatial localization of an obligate-killing, free-living pathogen generates a landscape of patches where new infections occur. As an infectious patch ages, both pathogen exposure at the patch and the probability of lethal infection following exposure can decline. We model stage-structured infectious patches, where non-lethal exposure can naturally "vaccinate" susceptible hosts. We let the between-stage difference in pathogen transmission, and then the between-stage difference in patch virulence, increase independently of other parameters. Effects of increasing either between-stage difference (about a fixed mean) depend on the probability a patch transitions from the first to second stage, i.e., the chance that a killer patch becomes a vaccinator. For slower stage transition, greater between-stage differences decreased susceptibles, and increased both resistant-host and killer patch numbers. But our examples reveal that each effect can be reversed when between-stage transition occurs more rapidly. For sufficiently rapid stage transition, increased between-stage virulence differences can lead to pathogen extinction, and leave the host at disease-free equilibrium. The model's general significance lies in demonstrating how epidemiological variation among sites of environmentally transmitted disease can strongly govern host-parasite dynamics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Giga-seal formation alters properties of sodium channels of human myoballs.

PubMed

Fahlke, C; Rüdel, R

1992-03-01

The influence of giga-seal formation on the properties of the Na+ channels within the covered membrane patch was investigated with a whole-cell pipette and a patch pipette applied to the same cell. Current kinetics, current/voltage relation and channel densities were determined in three combinations: (i) voltage-clamping and current recording with the whole-cell pipette, (ii) voltage-clamping with the whole-cell pipette and current recording with the patch pipette and, (iii) voltage-clamping and current recording with the patch pipette. The Hodgkin-Huxley (1952) parameters tau m and tau h were smaller for the patch currents than for the whole cell, and the h infinity curve was shifted in the negative direction. The channel density was of the order of 10 times smaller. All effects were independent of the extracellular Ca2+ concentration. The capacitive current generated in the patch by the whole-cell Na+ current and its effect on the transmembrane voltage of the patch were evaluated. The kinetic parameters of the Na+ channels in the patch did not depend on whether the voltage was clamped with the whole-cell pipette or the patch pipette. Thus, the results are not due to spurious voltage.

Internal habitat quality determines the effects of fragmentation on austral forest climbing and epiphytic angiosperms.

PubMed

Magrach, Ainhoa; Larrinaga, Asier R; Santamaría, Luis

2012-01-01

Habitat fragmentation has become one of the major threats to biodiversity worldwide, particularly in the case of forests, which have suffered enormous losses during the past decades. We analyzed how changes in patch configuration and habitat quality derived from the fragmentation of austral temperate rainforests affect the distribution of six species of forest-dwelling climbing and epiphytic angiosperms. Epiphyte and vine abundance is primarily affected by the internal characteristics of patches (such as tree size, the presence of logging gaps or the proximity to patch edges) rather than patch and landscape features (such as patch size, shape or connectivity). These responses were intimately related to species-specific characteristics such as drought- or shade-tolerance. Our study therefore suggests that plant responses to fragmentation are contingent on both the species' ecology and the specific pathways through which the study area is being fragmented, (i.e. extensive logging that shaped the boundaries of current forest patches plus recent, unregulated logging that creates gaps within patches). Management practices in fragmented landscapes should therefore consider habitat quality within patches together with other spatial attributes at landscape or patch scales.

Habitat patch size and nesting success of yellow-breasted chats

Treesearch

Dick E. Burhans; Frank R. Thompson III

1999-01-01

We measured vegetation at shrub patches used for nesting by Yellow-breasted Chats (Icteria virens) to evaluate the importance of nesting habitat patch features on nest predation, cowbird parasitism, and nest site selection. Logistic regression models indicated that nests in small patches (average diameter

Comparative Analysis of the Biaxial Mechanical Behavior of Carotid Wall Tissue and Biological and Synthetic Materials Used for Carotid Patch Angioplasty

PubMed Central

Kamenskiy, Alexey V.; Pipinos, Iraklis I.; MacTaggart, Jason N.; Jaffar Kazmi, Syed A.; Dzenis, Yuris A.

2011-01-01

Patch angioplasty is the most common technique used for the performance of carotid endarterectomy. A large number of patching materials are available for use while new materials are being continuously developed. Surprisingly little is known about the mechanical properties of these materials and how these properties compare with those of the carotid artery wall. Mismatch of the mechanical properties can produce mechanical and hemodynamic effects that may compromise the long-term patency of the endarterectomized arterial segment. The aim of this paper was to systematically evaluate and compare the biaxial mechanical behavior of the most commonly used patching materials. We compared PTFE (n = 1), Dacron (n = 2), bovine pericardium (n = 10), autogenous greater saphenous vein (n = 10), and autogenous external jugular vein (n = 9) with the wall of the common carotid artery (n = 18). All patching materials were found to be significantly stiffer than the carotid wall in both the longitudinal and circumferential directions. Synthetic patches demonstrated the most mismatch in stiffness values and vein patches the least mismatch in stiffness values compared to those of the native carotid artery. All biological materials, including the carotid artery, demonstrated substantial nonlinearity, anisotropy, and variability; however, the behavior of biological and biologically-derived patches was both qualitatively and quantitatively different from the behavior of the carotid wall. The majority of carotid arteries tested were stiffer in the circumferential direction, while the opposite anisotropy was observed for all types of vein patches and bovine pericardium. The rates of increase in the nonlinear stiffness over the physiological stress range were also different for the carotid and patching materials. Several carotid wall samples exhibited reverse anisotropy compared to the average behavior of the carotid tissue. A similar characteristic was observed for two of 19 vein patches. The obtained results quantify, for the first time, significant mechanical dissimilarity of the currently available patching materials and the carotid artery. The results can be used as guidance for designing more efficient patches with mechanical properties resembling those of the carotid wall. The presented systematic comparative mechanical analysis of the existing patching materials provides valuable information for patch selection in the daily practice of carotid surgery and can be used in future clinical studies comparing the efficacy of different patches in the performance of carotid endarterectomy. PMID:22168740

Steady-state plasma concentration profile of transdermal rotigotine: an integrated analysis of three, open-label, randomized, phase I multiple dose studies.

PubMed

Elshoff, Jan-Peer; Braun, Marina; Andreas, Jens-Otto; Middle, Michelle; Cawello, Willi

2012-04-01

The dopamine agonist rotigotine is formulated in a transdermal delivery system (patch) for once-daily application. It has been reported as efficacious in the treatment of idiopathic Parkinson's disease (PD) and restless legs syndrome. This article summarizes the results of 3 clinical studies conducted to characterize the 24-hour pharmacokinetic profile of rotigotine in steady state and the effect of different patch application sites on this profile. In addition, the relative bioavailability of a single, large patch versus 2 smaller patches was assessed. One Phase I study (SP871) assessed the steady-state pharmacokinetic properties at different application sites at a rotigotine maintenance dose of 3 mg/24 hours in healthy participants. Due to tolerability issues, the steady-state pharmacokinetic properties of rotigotine at higher doses (8 mg/24 hours) was assessed in 2 Phase I studies (SP630, SP651) in early-stage PD patients. Relative rotigotine bioavailability from a 40 cm(2) patch versus 2 × 20 cm(2) patches (SP651) and from a 15 cm(2) patch versus 1 × 5 cm(2) + 1 × 10 cm(2) patches (SP871) was also evaluated. Rotigotine concentrations in plasma were analyzed using a validated LC-MS/MS method. The pharmacokinetic variables were calculated using standard noncompartmental analysis. Release of rotigotine to the skin was 31% to 62% of total drug content in the patch. Variability of rotigotine exposure was low within participants (15%) compared with the variability observed between participants (54%). Rotigotine exposure increased proportionally in the therapeutic dose range of 2 mg/24 hours to 8 mg/24 hours. Plasma concentrations at steady state were stable over the 24-hour patch-on period. Delivery via a single, large patch compared with a combination of smaller patches did not appear to influence exposure to rotigotine. Bioavailability showed some variability depending on patch application site (hip, shoulder, abdomen, flank, thigh, upper arm); the respective mean ratios for AUC ranged between 0.87 (abdomen vs flank) and 1.46 (shoulder vs thigh). Continuous rotigotine delivery via a once-daily transdermal patch generated stable mean steady-state 24-hour plasma concentrations in healthy participants as well as patients with early-stage PD. Doses were achieved either by application of 1 large patch or a combination of smaller patches, resulting in the same total surface area. Copyright © 2012 Elsevier HS Journals, Inc. All rights reserved.

A clinical study of transdermal contraceptive patch in Thai adolescence women.

PubMed

Piyasirisilp, Rachatapon; Taneepanichskul, Surasak

2008-02-01

To study cycle control, compliance and safety of a transdermal contraceptive patch in adolescent Thai women. Fifty-eight healthy women were assigned to receive 3 cycles of contraceptive patch (ethinyl estradiol 20 microg and norelgestromin 150 microg/day). All participants aged 16-20 years were invited to participate from the family planning clinic at King Chulalongkorn Memorial Hospital. Data were collected on adverse effects, perceived advantages and disadvantages, body weight, blood pressure, patch detachments and compliance. Data were analyzed using mean, percentage and student's t-test. The participants' average age was 19.4 years, height 158.8 cm, weight 51.8 kg, BMI 20.8 Kg/m2. The most location of patch application was the abdomen and the most adverse event was breast tenderness (31.0%) followed by application site reaction, nausea vomiting and headache respectively. The breast symptom was mild in severity. The participants reported decrease in dysmenorrhea and shorter duration of bleeding. There were no significant changes in body weight and blood pressure. The improvement of their facial acne was reported. There were no pregnancies during use and the adhesion of the contraceptive patch is excellent. Partial patch detachment was reported in only 6.9%. No completed patch detachment was found. The present study found an overall positive impression of a new transdermal contraceptive patch. The good compliance and few side effects were demonstrated. The adhesive patch contraceptive was excellent.

Assessment of optimal strategies in a two-patch dengue transmission model with seasonality.

PubMed

Kim, Jung Eun; Lee, Hyojung; Lee, Chang Hyeong; Lee, Sunmi

2017-01-01

Emerging and re-emerging dengue fever has posed serious problems to public health officials in many tropical and subtropical countries. Continuous traveling in seasonally varying areas makes it more difficult to control the spread of dengue fever. In this work, we consider a two-patch dengue model that can capture the movement of host individuals between and within patches using a residence-time matrix. A previous two-patch dengue model without seasonality is extended by adding host demographics and seasonal forcing in the transmission rates. We investigate the effects of human movement and seasonality on the two-patch dengue transmission dynamics. Motivated by the recent Peruvian dengue data in jungle/rural areas and coast/urban areas, our model mimics the seasonal patterns of dengue outbreaks in two patches. The roles of seasonality and residence-time configurations are highlighted in terms of the seasonal reproduction number and cumulative incidence. Moreover, optimal control theory is employed to identify and evaluate patch-specific control measures aimed at reducing dengue prevalence in the presence of seasonality. Our findings demonstrate that optimal patch-specific control strategies are sensitive to seasonality and residence-time scenarios. Targeting only the jungle (or endemic) is as effective as controlling both patches under weak coupling or symmetric mobility. However, focusing on intervention for the city (or high density areas) turns out to be optimal when two patches are strongly coupled with asymmetric mobility.

Patch Time Allocation and Oviposition Behavior in Response to Patch Quality and the Presence of a Generalist Predator in Meteorus pulchricornis (Hymenoptera: Braconidae)

PubMed Central

Sheng, Sheng; Ling, Meng; Fu-an, Wu; Baoping, Li

2015-01-01

Foraging parasitoids often must estimate local risk of predation just as they must estimate local patch value. Here, we investigate the effects a generalist predator Chlaenius bioculatus (Coleoptera: Carabidae), has on the oviposition behavior and the patch residence decisions of a solitary parasitoid Meteorus pulchricornis (Hymenoptera: Braconidae) in response to the varying host quality of Spodoptera litura (Lepidoptera: Noctuidae) larvae (L2 and L4). M. pulchricornis attacked more L4 than on L2 hosts, with the difference in attack rate varying depending on predation treatments, greater in the presence (either actively feeding or not) of the predator than in the absence of it. The parasitoid attacked fewer L2 and L4 hosts when the predator was actively feeding than when it was not feeding or not present in the patch. M. pulchricornis decreased the patch leaving tendency with increasing rejections of hosts, but increased the tendency in response to the presence of the predator as compared with the absence of it, and furthermore, increased the patch leaving tendency when the predator was actively feeding as compared with when it was not. Our study suggests that M. pulchricornis can exploit high quality patches while minimizing predation risk, by attacking more hosts in high quality patches while reducing total patch time in response to risk of predation. PMID:25943317

Laparoscopic repair of perforated peptic ulcer: patch versus simple closure.

PubMed

Abd Ellatif, M E; Salama, A F; Elezaby, A F; El-Kaffas, H F; Hassan, A; Magdy, A; Abdallah, E; El-Morsy, G

2013-01-01

Laparoscopic correction of perforated peptic ulcer (PPU) has become an accepted way of management. Patch omentoplasty stayed for decades the main method of repair. The goal of the present study was to evaluate whether laparoscopic simple repair of PPU is as safe as patch omentoplasty. Since June 2005, 179 consecutive patients of PPU were treated by laparoscopic repair at our centers. We conducted a retrospective chart review in December 2012. Group I (patch group) included patients who were treated with standard patch omentoplasty. Group II (non-patch group) included patients who received simple repair without patch. From June 2007 to Dec. 2012, 179 consecutive patients of PPU who were treated by laparoscopic repair at our centers were enrolled in this multi-center retrospective study. 108 patients belong to patch group. While 71 patients were treated with laparoscopic simple repair. Operative time was significantly shorter in group II (non patch) (p = 0.01). No patient was converted to laparotomy. There was no difference in age, gender, ASA score, surgical risk (Boey's) score, and incidence of co-morbidities. Both groups were comparable in terms of hospital stay, time to resume oral intake, postoperative complications and surgical outcomes. Laparoscopic simple repair of PPU is a safe procedure compared with the traditional patch omentoplasty in presence of certain selection criteria. Copyright © 2013 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Reporting Recommended Patch Density from Vehicle Panel Vibration Convergence Studies using both DAF and TBL Fits of the Spatial Correlation Function

NASA Technical Reports Server (NTRS)

Smith, Andrew M.; Davis, Robert Ben; LaVerde, Bruce T.; Jones, Douglas C.; Band, Jonathon L.

2012-01-01

Using the patch method to represent the continuous spatial correlation function of a phased pressure field over a structural surface is an approximation. The approximation approaches the continuous function as patches become smaller. Plotting comparisons of the approximation vs the continuous function may provide insight revealing: (1) For what patch size/density should the approximation be very good? (2) What the approximation looks like when it begins to break down? (3) What the approximation looks like when the patch size is grossly too large. Following these observations with a convergence study using one FEM may allow us to see the importance of patch density. We may develop insights that help us to predict sufficient patch density to provide adequate convergence for the intended purpose frequency range of interest

Evaluations of dielectric property and drug release profile of 5-FU patches based on plasma charged electrets

NASA Astrophysics Data System (ADS)

Wang, YUAN; Hejuan, LIANG; Ping, HUANG; Xiaoqiang, AN; Jian, JIANG; Lili, CUI

2018-05-01

In the present study, the electret 5-fluorouracil patch was developed, the effective surface potential, piezoelectric coefficient d 33, open-circuit thermally stimulated discharge (TSD) current spectra and shear adhesion of the patch were measured. The drug release profile of the patch was determined by using high performance liquid chromatography method. A stable potential difference which was positively dependent on the surface potential of the electret was generated on two sides of the patch. The measurements of d 33 coefficient, TSD current spectra and adhesion performance showed that the electrostatic field of the electret could cause polarization and cohesive strength decreasing of the matrix molecules, change the distribution and interaction of the drug molecules in patch, therefore to increase the release of drug from the transdermal patch.

Multiple scales of patchiness and patch structure: a hierarchical framework for the study of heterogeneity

USGS Publications Warehouse

Kotliar, Natasha B.; Wiens, John A.

1990-01-01

We develop a hierarchical model of heterogeneity that provides a framework for classifying patch structure across a range of scales. Patches at lower levels in the hierarchy are more simplistic and correspond to the traditional view of patches. At levels approaching the upper bounds of the hierarchy the internal structure becomes more heterogeneous and boundaries more ambiguous. At each level in the hierarchy, patch structure will be influenced by both contrast among patches as well as the degree of aggregation of patches at lower levels in the hierarchy. We apply this model to foraging theory, but it has wider applications as in the study of habitat selection, population dynamics, and habitat fragmentation. It may also be useful in expanding the realm of landscape ecology beyond the current focus on anthropocentric scales.

Stratum corneum profiles of inflammatory mediators in patch test reactions to common contact allergens and sodium lauryl sulfate.

PubMed

Koppes, S A; Ljubojevic Hadzavdic, S; Jakasa, I; Franceschi, N; Jurakić Tončić, R; Marinović, B; Brans, R; Gibbs, S; Frings-Dresen, M H W; Rustemeyer, T; Kezic, S

2017-06-01

Recent studies have demonstrated allergen-specific differences in the gene expression of inflammatory mediators in patch tested skin. To determine levels of various inflammatory mediators in the stratum corneum (SC) after patch testing with common contact allergens and the skin irritant sodium lauryl sulfate (SLS). In total, 27 individuals who had previously patch tested positive to nickel, chromium, methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) or para-phenylenediamine were retested and then patch tested with SLS and petrolatum, with petrolatum serving as the patch test control. At 72 h, the test sites were clinically graded and the SC samples collected on adhesive tape. The levels of 18 of the 32 quantified mediators differed significantly from that of the control patches for at least one of the tested substances. SLS and MCI/MI induced the largest number of immunomediators. Interleukin (IL)-16 levels were significantly higher in patch test reactions in all allergens than they were in the controls, while no significant difference was detected for SLS. Furthermore, a strong negative correlation was found between strength of patch test reaction and IL-1α levels. Cytokine profiles in the SC of patch tested skin did not show a distinct allergen-specific pattern. However, MCI/MI induced a larger and wider immune response than the other allergens, perhaps due to its potency as an irritant. The levels of IL-16 were significantly increased in patch test reactions to allergens but not to SLS; thus, they may help clinicians to differentiate between allergic contact dermatitis and irritant contact dermatitis. © 2016 British Association of Dermatologists.

Grassland bird use of oak barrens and dry prairies in Wisconsin

USGS Publications Warehouse

Vos, Susan M.; Ribic, Christine A.

2011-01-01

Grassland bird populations have declined more than any other group of birds in North America and are of conservation concern to state and federal agencies. We determined relative abundances of grassland birds in oak barrens and dry sand prairies—native habitat types rare in the state of Wisconsin. We also investigated the association of relative abundance, patch size, and patch vegetation. Our study was conducted May–July 2000–2002 on Fort McCoy Military Installation in Monroe County, Wisconsin. Fourteen grassland bird species were found in native habitat patches. Vesper sparrow (Pooecetes gramineus), grasshopper sparrow (Ammodramus savannarum), and field sparrow (Spizella pusilla) were the most abundant grassland bird species; all are species of management concern in Wisconsin. Of the most abundant species, only grasshopper sparrow relative abundance increased as patch size increased; vesper sparrow and field sparrow relative abundances decreased as patch size increased. Though found at lower relative abundances, horned larks (Erephila alpestris), savannah sparrows (Passerculus sandwichensis), and upland sandpipers (Bartramia longicauda) were found at higher relative abundances as patch size increased. Patch vegetation was important for some species. Vesper sparrows were found at higher abundances in patches with shorter, less dense vegetation and higher woody cover, eastern meadowlark (Sturnella magna) relative abundances were higher in patches with higher proportions of grass, and dickcissel (Spiza americana) relative abundances were higher in patches with taller, denser vegetation and lower proportions of litter. Native habitats are important for grassland bird species of management concern and large patches are particularly important for some of them.

[Analysis of urban forest landscape pattern in Hefei].

PubMed

Wu, Zemin; Wu, Wenyou; Gao, Jian; Zhang, Shaojie

2003-12-01

Based on the theory and methodology of landscape ecology, the landscape pattern of the study area (17.6 km2) in the downtown of Hefei was analyzed by using the techniques of RS, GPS and GIS. The object was to provide a comprehensive method to study urban forest structure and its function in environmental improvement. The results showed that there were 5 major landscape elements, i.e., building and hard pavement surface, water, road, urban forest, and general green land in the area. The landscape matrix was building and pavement surface, occupied 73.13% of total land. Road was the typical corridor element in the city and occupied 6.89%. Green land occupied 11.44%, in which, urban forest patch occupied 9.18%. There were 408 urban forest patches, with an area of 161.16 hm2. The average area of the patch was 0.396 hm2, and the maximum area was 12 hm2. 48% of urban forest patch was identified as small scale patches with < 500 m2 of area, and only 8.6% of them was larger than 1 hm2. The number of general green land patch was 255, with an area of 39.74 hm2, which accounted for 2.26% of land area, and its average and maximum area was 0.1558 hm2 and 3.86 hm2, respectively. There were 147 water patches, with an area of 149.93 hm2, and occupied 8.54% of land, and the average and maximum area of the patch was 1.02 hm2 and 16 hm2, respectively. In the study area, both of the Shannon-Weiner landscape diversity index and evenness were low, only 0.928 and 0.576, respectively. In addition, the dominance of urban forest patch and general green land was 0.39 showing that the two landscape elements had a certain influence on the environment of the study area. The concept of interior habitat for forest was introduced in this paper, which was employed to make a scale class system of urban forest patch. The threshold area with interior habitat for urban forest patch was 9800 m2, and there was 31.69 hm2 of interior habitat of urban forest in total, which occupied 19.7% of the total area of urban forest patch. This situation was not favorable for providing more habitats to support species diversity. It's suggested that the concept of interior habitat could be employed to identify urban forest patch, and a scale system of small scale patch of urban forest-middle patch-large patch-extra large patch was build in the paper. Based on this system, the ratio of different scales of urban forest patch in the study area should be 2:2:2:3. The authors also suggested that larger pieces (1.5-3.0 hm2) of urban forest patch should be built, and more urban forests should be established in the northeastern part of the city in the future.

Expedient Repair Materials for Roadway Pavements

DTIC Science & Technology

2005-03-01

SILSPEC 900 PNS Patch/spall SSI Const. & Indus. Elastomeric conc. Matls Sikadur 22 Lo-Mod Sika Corp. Epoxy polymer concrete SikaTop 123 Plus Thin...patch Sika 2-component, polymer- 15 min modified Sikaset Roadway Patch Patch/spall Sika 1-comp. with high 15-25 min (15 min) (2000) alumina cement (not

Comprehensive field evaluation of asphalt patching methods and development of simple decision trees and a best practices manual.

DOT National Transportation Integrated Search

2017-06-01

The long-term performance of pothole patches largely depends on the selection of the patching method. A number of pothole patching methods are in practice in Minnesota and other nearby states. However, pavement maintenance crews often encounter probl...

A nonadjuvanted transcutaneous tetanus patch is effective in boosting anti-tetanus toxoid immune responses.

PubMed

Seid, Robert C; Reinisch, Christoph; Schlegl, Robert; Moehlen, Michael; Meinke, Andreas; Lundberg, Urban

2014-02-01

Dry tetanus toxoid (TTx) patches were formulated without any adjuvant, with excipients to impart antigen stabilization and to enhance skin delivery. The booster effects of the TTx patches were assessed using a guinea pig model. The study revealed significant rises in TTx IgG titers induced by the TTx patches after a low-dose subcutaneous (s.c.) prime with TTx adsorbed to aluminum hydroxide. The TTx patch can therefore be considered an effective alternative to a subcutaneous booster.

The Defender’s Dilemma: Charting a Course Toward Cybersecurity

DTIC Science & Technology

2015-01-01

Security concerns on the Internet began with the introduction of the Morris worm in November 1988,1 and since that time we have wit- nessed the...Patch Tuesday .” This is when security patches and updates are released for users to implement. As such, “Exploit Wednesday” usually fol- lows “Patch... Tuesday ,” as users are not generally quick to immediately patch their systems. 23 E.g., Oracle or Microsoft patch on a fixed schedule, but will make

Skin patch and vaginal ring versus combined oral contraceptives for contraception.

PubMed

Lopez, Laureen M; Grimes, David A; Gallo, Maria F; Stockton, Laurie L; Schulz, Kenneth F

2013-04-30

The delivery of combination contraceptive steroids from a transdermal contraceptive patch or a contraceptive vaginal ring offers potential advantages over the traditional oral route. The transdermal patch and vaginal ring could require a lower dose due to increased bioavailability and improved user compliance. To compare the contraceptive effectiveness, cycle control, compliance (adherence), and safety of the contraceptive patch or the vaginal ring versus combination oral contraceptives (COCs). Through February 2013, we searched MEDLINE, POPLINE, CENTRAL, LILACS, ClinicalTrials.gov, and ICTRP for trials of the contraceptive patch or the vaginal ring. Earlier searches also included EMBASE. For the initial review, we contacted known researchers and manufacturers to identify other trials. We considered randomized controlled trials comparing a transdermal contraceptive patch or a contraceptive vaginal ring with a COC. Data were abstracted by two authors and entered into RevMan. For dichotomous variables, the Peto odds ratio (OR) with 95% confidence intervals (CI) was calculated. For continuous variables, the mean difference was computed. We also assessed the quality of evidence for this review. We found 18 trials that met our inclusion criteria. Of six patch studies, five examined the marketed patch containing norelgestromin plus ethinyl estradiol (EE); one studied a patch in development that contains levonorgestrel (LNG) plus EE. Of 12 vaginal ring trials, 11 examined the same marketing ring containing etonogestrel plus EE; one studied a ring being developed that contains nesterone plus EE.Contraceptive effectiveness was not significantly different for the patch or ring versus the comparison COC. Compliance data were limited. Patch users showed better compliance than COC users in three trials. For the norelgestromin plus EE patch, ORs were 2.05 (95% CI 1.83 to 2.29) and 2.76 (95% CI 2.35 to 3.24). In the levonorgestrel plus EE patch report, patch users were less likely to have missed days of therapy (OR 0.36; 95% CI 0.25 to 0.51). Of four vaginal ring trials, one found ring users had more noncompliance (OR 3.99; 95% CI 1.87 to 8.52), while another showed more compliance with the regimen (OR 1.67; 95% CI 1.04 to 2.68).More patch users discontinued early than COC users. ORs from two meta-analyses were 1.59 (95% CI 1.26 to 2.00) and 1.56 (95% CI 1.18 to 2.06) and another trial showed OR 2.57 (95% CI 0.99 to 6.64). Patch users also had more discontinuation due to adverse events than COC users. Users of the norelgestromin-containing patch reported more breast discomfort, dysmenorrhea, nausea, and vomiting. In the levonorgestrel-containing patch trial, patch users reported less vomiting, headaches, and fatigue.Of 11 ring trials with discontinuation data, two showed the ring group discontinued less than the COC group: OR 0.32 (95% CI 0.16 to 0.66) and OR 0.52 (95% CI 0.31 to 0.88). Ring users were less likely to discontinue due to adverse events in one study (OR 0.32; 95% CI 0.15 to 0.70). Compared to the COC users, ring users had more vaginitis and leukorrhea but less vaginal dryness. Ring users also reported less nausea, acne, irritability, depression, and emotional lability than COC users.For cycle control, only one trial study showed a significant difference. Women in the patch group were less likely to have breakthrough bleeding and spotting. Seven ring studies had bleeding data; four trials showed the ring group generally had better cycle control than the COC group. Effectiveness was not significantly different for the methods compared. Pregnancy data were available from half of the patch trials but two-thirds of ring trials. The patch could lead to more discontinuation than the COC. The patch group had better compliance than the COC group. Compliance data came from half of the patch studies and one-third of the ring trials. Patch users had more side effects than the COC group. Ring users generally had fewer adverse events than COC users but more vaginal irritation and discharge.The quality of the evidence for this review was considered low for the patch and moderate for the ring. The main reasons for downgrading were lack of information on the randomization sequence generation or allocation concealment, the outcome assessment methods, high losses to follow up, and exclusions after randomization.

Patched-grid calculations with the Euler and Navier-Stokes equations: Theory and applications

NASA Technical Reports Server (NTRS)

Rai, M. M.

1986-01-01

A patched-grid approach is one in which the flow region of interest is divided into subregions which are then discretized independently using existing grid generator. The equations of motion are integrated in each subregion in conjunction with patch-boundary schemes which allow proper information transfer across interfaces that separate subregions. The patched-grid approach greatly simplifies the treatment of complex geometries and also the addition of grid points to selected regions of the flow. A conservative patch-boundary condition that can be used with explicit, implicit factored and implicit relaxation schemes is described. Several example calculations that demonstrate the capabilities of the patched-grid scheme are also included.

Implementation for wideband applications using UWB fractal patch antenna

NASA Astrophysics Data System (ADS)

Kumar, D. Naresh

2018-04-01

This paper defines in detail about the diverse fractal patch antenna. Microstrip patch antennas has evolved in the field of research and development extending its impact across wide range of applications. A combination of patch antenna with fractal patterns has become a tryout to outspread it further. Because of its low profile nature patch antennas have added to a lot of prominence. Apart from have this property it can also be renovated further for wide bandwidth (2929 MHz) applications, as it exhibits self-analogous property. This antenna is premeditated on a patch using Sierpinski(4.040 GHz, 6.566 GHz) and Koch fractal geometries respectively. The antenna is designed using HFSS software.

MS lesion segmentation using a multi-channel patch-based approach with spatial consistency

NASA Astrophysics Data System (ADS)

Mechrez, Roey; Goldberger, Jacob; Greenspan, Hayit

2015-03-01

This paper presents an automatic method for segmentation of Multiple Sclerosis (MS) in Magnetic Resonance Images (MRI) of the brain. The approach is based on similarities between multi-channel patches (T1, T2 and FLAIR). An MS lesion patch database is built using training images for which the label maps are known. For each patch in the testing image, k similar patches are retrieved from the database. The matching labels for these k patches are then combined to produce an initial segmentation map for the test case. Finally a novel iterative patch-based label refinement process based on the initial segmentation map is performed to ensure spatial consistency of the detected lesions. A leave-one-out evaluation is done for each testing image in the MS lesion segmentation challenge of MICCAI 2008. Results are shown to compete with the state-of-the-art methods on the MICCAI 2008 challenge.

A Pragmatic Approach to Patch Testing Atopic Dermatitis Patients: Clinical Recommendations Based on Expert Consensus Opinion.

PubMed

Chen, Jennifer K; Jacob, Sharon E; Nedorost, Susan T; Hanifin, Jon M; Simpson, Eric L; Boguniewicz, Mark; Watsky, Kalman L; Lugo-Somolinos, Aida; Hamann, Carsten R; Eberting, Cheryl Lee; Silverberg, Jonathan I; Thyssen, Jacob P

2016-01-01

Allergic contact dermatitis (ACD) may complicate the clinical course of atopic dermatitis (AD), and patch testing remains the criterion standard for diagnosing ACD. To date, there have been no guidelines or consensus recommendations on when and how to patch test individuals with AD. Failure to patch test when appropriate may result in overlooking an important and potentially curable complicating comorbidity. In this article, we present consensus recommendations regarding when to perform patch testing in the AD patient, best practices, and common pitfalls. Patch testing should be considered in AD patients with dermatitis that fails to improve with topical therapy; with atypical/changing distribution of dermatitis, or pattern suggestive of ACD; with therapy-resistant hand eczema in the working population; with adult- or adolescent-onset AD; and/or before initiating systemic immunosuppressants for the treatment of dermatitis. A suggested patch testing algorithm for AD patients is provided.

Forest Patch Size, Land Use, and Mesic Forest Herbs in the French Broad River Basin, North Carolina

Treesearch

Scott M. Pearson; Alan B. Smith; Monica G. Turner

1998-01-01

The effect of forest fragmentation on cove-forest herbs was studied in the Southern Blue Ridge Province. Patches of mesic forests were sampled with 4 ha study plots. The coverage and density of herb species were greater in large patches (>200 ha) than in small patches (

Fentanyl patches: preventable overdose.

PubMed

2010-02-01

Fentanyl is a potent opioid analgesic marketed for the treatment of stable intense chronic pain, particularly in the form of a transdermal patch. These delivery devices carry the same risk of adverse effects and drug interactions as conventional formulations of opioids. The patches carry an added risk of fentanyl overdose because they contain very high doses, both before and after use. High-risk situations for overdose were identified by examining the results of pharmacovigilance studies and medication error prevention programmes, as well as an observational study, case reports, and a French legal action. The main situations exposing patients to a risk of overdose are: confusion between two dose strengths, forgetting to remove the patch; accidental transfer of the patch to another person, application of more than one patch, cutting the patches, self-medication, and ingestion. Increased skin temperature facilitates fentanyl absorption and thus increases the risk of overdose; high-risk situations include fever, electric blankets, and intense physical exercise. In practice, the precautions for treatment and patch disposal must be followed exactly if this delivery system is to serve as a valid alternative to morphine for selected patients with stable intense chronic pain.

Aqua-planet simulations of the formation of the South Atlantic convergence zone

NASA Technical Reports Server (NTRS)

Nieto Ferreira, Rosana; Chao, Winston C.

2013-01-01

The impact of Amazon Basin convection and cold fronts on the formation and maintenance of the South Atlantic convergence zone (SACZ) is studied using aqua-planet simulations with a general circulation model. In the model, a circular patch of warm sea-surface temperature (SST) is used to mimic the effect of the Amazon Basin on South American monsoon convection. The aqua-planet simulations were designed to study the effect of the strength and latitude of Amazon Basin convection on the formation of the SACZ. The simulations indicate that the strength of the SACZ increases as the Amazon convection intensifies and is moved away from the equator. Of the two controls studied here, the latitude of the Amazon convection exerts the strongest effect on the strength of the SACZ. An analysis of the synoptic-scale variability in the simulations shows the importance of frontal systems in the formation of the aqua-planet SACZ. Composite time series of frontal systems that occurred in the simulations show that a robust SACZ occurs when fronts penetrate into the subtropics and become stationary there as they cross eastward of the longitude of the Amazon Basin. Moisture convergence associated with these frontal systems produces rainfall not along the model SACZ region and along a large portion of the northern model Amazon Basin. Simulations in which the warm SST patch was too weak or too close to the equator did not produce frontal systems that extended into the tropics and became stationary, and did not form a SACZ. In the model, the SACZ forms as Amazon Basin convection strengthens and migrates far enough southward to allow frontal systems to penetrate into the tropics and stall over South America. This result is in agreement with observations that the SACZ tends to form after the onset of the monsoon season in the Amazon Basin.

Landscape epidemiology in urban environments: The example of rodent-borne Trypanosoma in Niamey, Niger.

PubMed

Rossi, Jean-Pierre; Kadaouré, Ibrahima; Godefroid, Martin; Dobigny, Gauthier

2017-10-05

Trypanosomes are protozoan parasites found worldwide, infecting humans and animals. In the past decade, the number of reports on atypical human cases due to Trypanosoma lewisi or T. lewisi-like has increased urging to investigate the multiple factors driving the disease dynamics, particularly in cities where rodents and humans co-exist at high densities. In the present survey, we used a species distribution model, Maxent, to assess the spatial pattern of Trypanosoma-positive rodents in the city of Niamey. The explanatory variables were landscape metrics describing urban landscape composition and physiognomy computed from 8 land-cover classes. We computed the metrics around each data location using a set of circular buffers of increasing radii (20m, 40m, 60m, 80m and 100m). For each spatial resolution, we determined the optimal combination of feature class and regularization multipliers by fitting Maxent with the full dataset. Since our dataset was small (114 occurrences) we expected an important uncertainty associated to data partitioning into calibration and evaluation datasets. We thus performed 350 independent model runs with a training dataset representing a random subset of 80% of the occurrences and the optimal Maxent parameters. Each model yielded a map of habitat suitability over Niamey, which was transformed into a binary map implementing a threshold maximizing the sensitivity and the specificity. The resulting binary maps were combined to display the proportion of models that indicated a good environmental suitability for Trypanosoma-positive rodents. Maxent performed better with landscape metrics derived from buffers of 80m. Habitat suitability for Trypanosoma-positive rodents exhibited large patches linked to urban features such as patch richness and the proportion of landscape covered by concrete or tarred areas. Such inferences could be helpful in assessing areas at risk, setting of monitoring programs, public and medical staff awareness or even vaccination campaigns. Copyright © 2017 Elsevier B.V. All rights reserved.

Postnatal Development of Intrinsic Horizontal Axons in Macaque Inferior Temporal and Primary Visual Cortices.

PubMed

Wang, Quanxin; Tanigawa, Hisashi; Fujita, Ichiro

2017-04-01

Two distinct areas along the ventral visual stream of monkeys, the primary visual (V1) and inferior temporal (TE) cortices, exhibit different projection patterns of intrinsic horizontal axons with patchy terminal fields in adult animals. The differences between the patches in these 2 areas may reflect differences in cortical representation and processing of visual information. We studied the postnatal development of patches by injecting an anterograde tracer into TE and V1 in monkeys of various ages. At 1 week of age, labeled patches with distribution patterns reminiscent of those in adults were already present in both areas. The labeling intensity of patches decayed exponentially with projection distance in monkeys of all ages in both areas, but this trend was far less evident in TE. The number and extent of patches gradually decreased with age in V1, but not in TE. In V1, axonal and bouton densities increased postnatally only in patches with short projection distances, whereas in TE this density change occurred in patches with various projection distances. Thus, patches with area-specific distribution patterns are formed early in life, and area-specific postnatal developmental processes shape the connectivity of patches into adulthood. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Relative abundance of mesopredators and size of oak patches in the cross-timbers ecoregion

USGS Publications Warehouse

Disney, M.R.; Hellgren, E.C.; Davis, C.A.; Leslie, David M.; Engle, David M.

2008-01-01

Mesopredators (e.g., raccoon Procyon lotor, Virginia opossum Didelphis virginiana, striped skunk Mephitis mephitis) have received considerable attention because of links to population declines in birds via increased nest predation, especially in landscapes fragmented by anthropogenic forces. Relationships of abundance of mesopredators to size of habitat patches have received less attention than relationships to other metrics of fragmentation, particularly edge characteristics. We tested the hypothesis that relative abundance of mesopredators (e.g., raccoons and Virginia opossums) was related negatively to size of forest patch. We delineated 15 patches of oak (Quercus) forest ranging from 0.2 to 55.3 ha within a grassland-woodland mosaic in the cross-timbers ecoregion of Oklahoma. Scent stations and live traps within these patches were used to index relative abundance of mesopredators in summers 2003 and 2004. Both indices of relative abundance were related weakly and negatively to area of forest patch. However, rate of capture and visitation to scent station were not correlated consistently throughout the study. Our results suggested that the two methods to index abundance provided separate information on functional and numerical responses to size of patch. Our evidence that mesopredators within the cross timbers were more likely to be in smaller patches of oak forest may have implications to success of avian nesting in these patches.

Mucoadhesive buccal patches based on interpolymer complexes of chitosan–pectin for delivery of carvedilol

PubMed Central

Kaur, Amanpreet; Kaur, Gurpreet

2011-01-01

The study was designed to develop bioadhesive patches of carvedilol hydrochloride using chitosan (CH) and pectin (PE) interpolymer complexes and to systematically evaluate their in vitro and in vivo performances. Mucoadhesive buccal patches of carvedilol were prepared using solvent casting method. The physicochemical interaction between CH and PE was investigated by FTIR and DSC studies. The patches were evaluated for their physical characteristics like mass variation, content uniformity, folding endurance, ex vivo mucoadhesion strength, ex vivo mucoadhesion time, surface pH, in vitro drug release, in situ release study, and in vivo bioavailability study. The swelling index of the patches was found to be proportional to the PE concentration. The surface pH of all the formulated bioadhesive patches was found to lie between 6.2 and 7.2. The optimized bioadhesive patch (C1, CH:PE 20:80) showed bioadhesive strength of 22.10 ± 0.20 g, in vitro release of 98.73% and ex vivo mucoadhesion time of 451 min with in a period of 8 h. The optimized patch demonstrated good in vitro and in vivo results. The buccal delivery of carvedilol in rabbits showed a significant improvement in bioavailability of carvedilol from patches when compared to oral route. PMID:23960773

Mucoadhesive buccal patches based on interpolymer complexes of chitosan-pectin for delivery of carvedilol.

PubMed

Kaur, Amanpreet; Kaur, Gurpreet

2012-01-01

The study was designed to develop bioadhesive patches of carvedilol hydrochloride using chitosan (CH) and pectin (PE) interpolymer complexes and to systematically evaluate their in vitro and in vivo performances. Mucoadhesive buccal patches of carvedilol were prepared using solvent casting method. The physicochemical interaction between CH and PE was investigated by FTIR and DSC studies. The patches were evaluated for their physical characteristics like mass variation, content uniformity, folding endurance, ex vivo mucoadhesion strength, ex vivo mucoadhesion time, surface pH, in vitro drug release, in situ release study, and in vivo bioavailability study. The swelling index of the patches was found to be proportional to the PE concentration. The surface pH of all the formulated bioadhesive patches was found to lie between 6.2 and 7.2. The optimized bioadhesive patch (C1, CH:PE 20:80) showed bioadhesive strength of 22.10 ± 0.20 g, in vitro release of 98.73% and ex vivo mucoadhesion time of 451 min with in a period of 8 h. The optimized patch demonstrated good in vitro and in vivo results. The buccal delivery of carvedilol in rabbits showed a significant improvement in bioavailability of carvedilol from patches when compared to oral route.

Pharmacokinetic Evaluation of Two Nicotine Patches in Smokers.

PubMed

Rasmussen, Scott; Horkan, Kathleen Halabuk; Kotler, Mitchell

2018-02-02

Smoking continues to be a major preventable cause of early mortality worldwide, and nicotine replacement therapy has been demonstrated to increase rates of abstinence among smokers attempting to quit. Nicotine transdermal systems (also known as nicotine patches) attach to the skin via an adhesive layer composed of a mixture of different-molecular-weight polyisobutylenes (PIBs) in a specific ratio. This randomized, single-dose, 2-treatment, crossover pharmacokinetic (PK) trial assessed the bioequivalence of nicotine patches including a replacement PIB adhesive (test) compared with the PIB adhesive historically used on marketed patches (reference). The test and reference patches were bioequivalent, as determined by the PK parameters of C max and AUC 0-t . In addition, the parameters T max and t 1/2 did not significantly differ between the 2 patches, supporting the bioequivalence finding from the primary analysis. The tolerability profiles of the patches containing the replacement and previously used PIB adhesives were similar; application-site adverse events did not significantly differ between test and reference patches. Overall, these data establish the bioequivalence of the nicotine patch with the replacement PIB adhesive formulation and the previously utilized PIB adhesive formulation. © 2018 The Authors. Clinical Pharmacology in Drug Development published by Wiley Periodicals, Inc. on behalf of The American College of Clinical Pharmacology.

The dose-response relationship between the patch test and ROAT and the potential use for regulatory purposes.

PubMed

Fischer, Louise Arup; Voelund, Aage; Andersen, Klaus Ejner; Menné, Torkil; Johansen, Jeanne Duus

2009-10-01

Allergic contact dermatitis is common and can be prevented. The relationship between thresholds for patch tests and the repeated open application test (ROAT) is unclear. It would be desirable if patch test and ROAT data from already sensitized individuals could be used in prevention. The aim was to develop an equation that could predict the response to an allergen in a ROAT based on the dose-response curve derived by patch testing. Results from two human experimental elicitation studies with non-volatile allergens, nickel and the preservative methyldibromo glutaronitrile (MDBGN), were analysed by logistic dose-response statistics. The relation for volatile compounds was investigated using the results from experiments with the fragrance chemicals hydroxyisohexyl 3-cyclohexene carboxaldehyde and isoeugenol. For non-volatile compounds, the outcome of a ROAT can be estimated from the patch test by: ED(xx)(ROAT) = 0.0296 ED(xx)(patch test). For volatile compounds, the equation predicts that the response in the ROAT is more severe than the patch test response, but it overestimates the response. This equation may be used for non-volatile compounds other than nickel and MDBGN, after further validation. The relationship between the patch test and the ROAT can be used for prevention, to set safe levels of allergen exposure based on patch test data.

Results of patch testing in 10 patients with peristomal dermatitis.

PubMed

Landis, Megan N; Keeling, James H; Yiannias, James A; Richardson, Donna M; Nordberg Linehan, Diane L; Davis, Mark D P

2012-09-01

Peristomal dermatitis is a common problem in patients with ostomies that is a source of considerable morbidity. Irritant contact dermatitis is most common, but allergic contact dermatitis can also occur. Because of the lack of published reports on patch testing for this indication, we undertook a retrospective study of patch testing results in patients with suspected peristomal allergic contact dermatitis. We sought to describe our patch testing experience with patients referred with peristomal dermatitis. This was a retrospective review of medical records of patients with ostomies and peristomal dermatitis who underwent patch testing in the Mayo Clinic Departments of Dermatology in Jacksonville, FL; Rochester, MN; and Scottsdale, AZ, during a 10-year period (2000-2010). Ten patients with peristomal dermatitis were referred for patch testing (6 in Minnesota, 2 in Florida, and 2 in Arizona). Patients were patch tested to the materials used in their stoma devices, to the standard series, and in some cases to supplemental series. All 10 had at least one allergic patch test reaction, most commonly to stoma paste (3 of 10 patients). Retrospective nature of study via chart review is a limitation. Patch testing is a useful tool for identification of allergens in patients with peristomal dermatitis. Copyright © 2011 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

Pharmacokinetics of Memantine after a Single and Multiple Dose of Oral and Patch Administration in Rats.

PubMed

Lee, Soo-Han; Kim, Seung-Hyun; Noh, Yook-Hwan; Choi, Byung-Moon; Noh, Gyu-Jeong; Park, Woo-Dae; Kim, Eun-Jung; Cho, Ik-Hyun; Bae, Chun-Sik

2016-02-01

Memantine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist used to treat Alzheimer's disease. We investigated memantine pharmacokinetics after oral, IV and patch administration in rats, and compared memantine pharmacokinetics after multiple- or single-dose oral and transdermal administration. Venous blood was collected at preset intervals in single- and multiple-dose studies. Non-compartmental pharmacokinetics was analysed for all formulations. The oral, IV and patch memantine doses were 10 mg/kg, 2 mg/kg and 8.21 ± 0.89 mg/kg, respectively. The maximum plasma concentration was lower and the half-life longer after patch administration than oral and IV administration. Memantine bioavailability was 41 and 63% for oral and patch administration, respectively. Steady state was achieved around 24 hr for oral and patch administration. The mean AUC increased after oral or patch administration from single to multiple dose. The memantine patch formulation displayed a longer duration of action and lower peak plasma concentration. However, drug exposure was similar to the oral formulation at each dose. Additionally, the memantine patch formulation displayed a smaller interindividual variability and lower accumulation than the oral formulation. © 2015 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Rotator cuff repair with a tendon-fibrocartilage-bone composite bridging patch.

PubMed

Ji, Xiaoxi; Chen, Qingshan; Thoreson, Andrew R; Qu, Jin; An, Kai-Nan; Amadio, Peter C; Steinmann, Scott P; Zhao, Chunfeng

2015-11-01

To compare the mechanical performance of a rotator cuff repaired with a novel tendon-fibrocartilage-bone composite bridging patch vs the traditional Mason-Allen repair in an in vitro canine model. Twenty shoulders and 10 bridging patches from patellar tendon were harvested. The patches were trimmed and sliced into 2 layers. An infraspinatus tendon tear was created in each shoulder. Modified Mason-Allen sutures were used to repair the infraspinatus tendon to the greater tuberosity, with or without the bridging patch (bridging patch group and controls, respectively). Shoulders were loaded to failure under displacement control at a rate of 0.5mm/s. The ultimate tensile load was significantly higher in the bridging patch group than control (mean [SD], 365.46 [36.45] vs 272.79 [48.88] N; P<.001). Stiffness at the greater tuberosity repair site and the patch-infraspinatus tendon repair site was significantly higher than the control repair site (93.96 [27.72] vs 42.62 [17.48] N/mm P<.001; 65.94 [24.51] vs 42.62 [17.48] N/mm P=.02, respectively). The tendon-fibrocartilage-bone composite bridging patch achieved higher ultimate tensile load and stiffness at the patch-greater tuberosity repair site compared with traditional repair in a canine model. This composite tissue transforms the traditional tendon-to-bone healing interface (with dissimilar tissues) into a pair of bone-to-bone and tendon-to-tendon interfaces, which may improve healing quality and reduce retear rate. Copyright © 2015 Elsevier Ltd. All rights reserved.

Integration of autopatching with automated pipette and cell detection in vitro

PubMed Central

Wu (吴秋雨), Qiuyu; Kolb, Ilya; Callahan, Brendan M.; Su, Zhaolun; Stoy, William; Kodandaramaiah, Suhasa B.; Neve, Rachael; Zeng, Hongkui; Boyden, Edward S.; Forest, Craig R.

2016-01-01

Patch clamp is the main technique for measuring electrical properties of individual cells. Since its discovery in 1976 by Neher and Sakmann, patch clamp has been instrumental in broadening our understanding of the fundamental properties of ion channels and synapses in neurons. The conventional patch-clamp method requires manual, precise positioning of a glass micropipette against the cell membrane of a visually identified target neuron. Subsequently, a tight “gigaseal” connection between the pipette and the cell membrane is established, and suction is applied to establish the whole cell patch configuration to perform electrophysiological recordings. This procedure is repeated manually for each individual cell, making it labor intensive and time consuming. In this article we describe the development of a new automatic patch-clamp system for brain slices, which integrates all steps of the patch-clamp process: image acquisition through a microscope, computer vision-based identification of a patch pipette and fluorescently labeled neurons, micromanipulator control, and automated patching. We validated our system in brain slices from wild-type and transgenic mice expressing channelrhodopsin 2 under the Thy1 promoter (line 18) or injected with a herpes simplex virus-expressing archaerhodopsin, ArchT. Our computer vision-based algorithm makes the fluorescent cell detection and targeting user independent. Compared with manual patching, our system is superior in both success rate and average trial duration. It provides more reliable trial-to-trial control of the patching process and improves reproducibility of experiments. PMID:27385800

Patch time allocation and oviposition behavior in response to patch quality and the presence of a generalist predator in Meteorus pulchricornis (Hymenoptera: Braconidae).

PubMed

Sheng, Sheng; Ling, Meng; Fu-An, Wu; Baoping, Li

2015-01-01

Foraging parasitoids often must estimate local risk of predation just as they must estimate local patch value. Here, we investigate the effects a generalist predator Chlaenius bioculatus (Coleoptera: Carabidae), has on the oviposition behavior and the patch residence decisions of a solitary parasitoid Meteorus pulchricornis (Hymenoptera: Braconidae) in response to the varying host quality of Spodoptera litura (Lepidoptera: Noctuidae) larvae (L2 and L4). M. pulchricornis attacked more L4 than on L2 hosts, with the difference in attack rate varying depending on predation treatments, greater in the presence (either actively feeding or not) of the predator than in the absence of it. The parasitoid attacked fewer L2 and L4 hosts when the predator was actively feeding than when it was not feeding or not present in the patch. M. pulchricornis decreased the patch leaving tendency with increasing rejections of hosts, but increased the tendency in response to the presence of the predator as compared with the absence of it, and furthermore, increased the patch leaving tendency when the predator was actively feeding as compared with when it was not. Our study suggests that M. pulchricornis can exploit high quality patches while minimizing predation risk, by attacking more hosts in high quality patches while reducing total patch time in response to risk of predation. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

Assessment of optimal strategies in a two-patch dengue transmission model with seasonality

PubMed Central

Lee, Chang Hyeong; Lee, Sunmi

2017-01-01

Emerging and re-emerging dengue fever has posed serious problems to public health officials in many tropical and subtropical countries. Continuous traveling in seasonally varying areas makes it more difficult to control the spread of dengue fever. In this work, we consider a two-patch dengue model that can capture the movement of host individuals between and within patches using a residence-time matrix. A previous two-patch dengue model without seasonality is extended by adding host demographics and seasonal forcing in the transmission rates. We investigate the effects of human movement and seasonality on the two-patch dengue transmission dynamics. Motivated by the recent Peruvian dengue data in jungle/rural areas and coast/urban areas, our model mimics the seasonal patterns of dengue outbreaks in two patches. The roles of seasonality and residence-time configurations are highlighted in terms of the seasonal reproduction number and cumulative incidence. Moreover, optimal control theory is employed to identify and evaluate patch-specific control measures aimed at reducing dengue prevalence in the presence of seasonality. Our findings demonstrate that optimal patch-specific control strategies are sensitive to seasonality and residence-time scenarios. Targeting only the jungle (or endemic) is as effective as controlling both patches under weak coupling or symmetric mobility. However, focusing on intervention for the city (or high density areas) turns out to be optimal when two patches are strongly coupled with asymmetric mobility. PMID:28301523

Methamphetamine-induced stereotypy correlates negatively with patch-enhanced prodynorphin and arc mRNA expression in the rat caudate putamen: the role of mu opioid receptor activation.

PubMed

Horner, Kristen A; Noble, Erika S; Gilbert, Yamiece E

2010-06-01

Amphetamines induce stereotypy, which correlates with patch-enhanced c-Fos expression the patch compartment of caudate putamen (CPu). Methamphetamine (METH) treatment also induces patch-enhanced expression of prodynorphin (PD), arc and zif/268 in the CPu. Whether patch-enhanced activation of any of these genes correlates with METH-induced stereotypy is unknown, and the factors that contribute to this pattern of expression are poorly understood. Activation of mu opioid receptors, which are expressed by the neurons of the patch compartment, may underlie METH-induced patch-enhanced gene expression and stereotypy. The current study examined whether striatal mu opioid receptor blockade altered METH-induced stereotypy and patch-enhanced gene expression, and if there was a correlation between the two responses. Animals were intrastriatally infused with the mu antagonist CTAP (10 microg/microl), treated with METH (7.5 mg/kg, s.c.), placed in activity chambers for 3h, and then sacrificed. CTAP pretreatment attenuated METH-induced increases in PD, arc and zif/268 mRNA expression and significantly reduced METH-induced stereotypy. Patch-enhanced PD and arc mRNA expression in the dorsolateral CPu correlated negatively with METH-induced stereotypy. These data indicate that mu opioid receptor activation contributes to METH-induced gene expression in the CPu and stereotypy, and that patch-enhanced PD and arc expression may be a homeostatic response to METH treatment. Copyright 2010 Elsevier Inc. All rights reserved.

Methamphetamine-Induced Stereotypy Correlates Negatively with Patch-Enhanced Prodynorphin and ARC mRNA Expression in the Rat Caudate Putamen: The Role of Mu Opioid Receptor Activation

PubMed Central

Horner, Kristen A.; Noble, Erika S.; Gilbert, Yamiece E.

2010-01-01

Amphetamines induce stereotypy, which correlates with patch-enhanced c-Fos expression the patch compartment of caudate putamen (CPu). Methamphetamine (METH) treatment also induces patch-enhanced expression of prodynorphin (PD), arc and zif/268 in the CPu. Whether patch-enhanced activation of any of these genes correlates with METH-induced stereotypy is unknown, and the factors that contribute to this pattern of expression are poorly understood. Activation of mu opioid receptors, which are expressed by the neurons of the patch compartment, may underlie METH-induced patch-enhanced gene expression and stereotypy. The current study examined whether striatal mu opioid receptor blockade altered METH-induced stereotypy and patch-enhanced gene expression, and if there was a correlation between the two responses. Animals were intrastriatally infused with the mu antagonist CTAP (10 μg/μl), treated with METH (7.5 mg/kg, s.c.), placed in activity chambers for 3h, and then sacrificed. CTAP pretreatment attenuated METH-induced increases in PD, arc and zif/268 mRNA expression and significantly reduced METH-induced stereotypy. Patch-enhanced PD and arc mRNA expression in the dorsolateral CPu correlated negatively with METH-induced stereotypy. These data indicate that mu opioid receptor activation contributes to METH-induced gene expression in the CPu and stereotypy, and that patch-enhanced PD and arc expression may be a homeostatic response to METH treatment. PMID:20298714

[Face protective patches do not reduce facial pressure ulcers in a simulated model of non-invasive ventilation].

PubMed

Riquelme M, Hugo; Wood V, David; Martínez F, Santiago; Carmona M, Fernando; Peña V, Axel; Wegner A, Adriana

2017-06-01

Noninvasive ventilation (NIV) frequently involves the development of facial pressure ulcers (FPU). Its prevention considers the empirical use of protective patches between skin and mask, in order to reduce the pressure exerted by it. To evaluate the effect of protective patches on the pressure exerted by the facial mask, and its impact on the programmed ventilatory parameters. Bilevel NIV simulated model using full face mask in phantom with a physiological airway (ALS PRO +) in supine position. Forehead, chin and cheekbones pressure were measured using 3 types of standard protective patches versus a control group using pressure sensors (Interlinks Electronics®). The values obtained with the protective patches-mask model were evaluated in the programmed variables maximum inspiratory flow (MIF)), expired tidal volume (Vte) and positive inspiratory pressure (IPAP), with Trilogy 100 ventilator, Respironics®. The programming and recording of the variables was carried out in 8 opportunities in each group by independent operators. There was no decrease in facial pressure with any of the protective patches compared to the control group. Moltopren increased facial pressure at all support points (p < 0.001), increased leakage, it decreased MIF, Vte and IPAP (p < 0.001). Hydrocolloid patches increased facial pressure only in the left cheekbone, increased leakage and decreased MIF. Polyurethane patches did not produce changes in facial pressure or ventilatory variables. The use of protective patches of moltopren, hydrocolloid and polyurethane transparent did not contribute to the decrease of the facial pressure. A deleterious effect of the moltopren and hydrocolloid patches was observed on the administration of ventilatory variables, concluding that the non-use of the protective patches allowed a better administration of the programmed parameters.

Tolerability of the capsaicin 8% patch following pretreatment with lidocaine or tramadol in patients with peripheral neuropathic pain: a multicentre, randomized, assessor-blinded study.

PubMed

Jensen, T S; Høye, K; Fricová, J; Vanelderen, P; Ernault, E; Siciliano, T; Marques, S

2014-10-01

Application of the capsaicin 8% patch is associated with treatment-related discomfort. Consequently, pretreatment for 60 min with anaesthetic cream is recommended; however, this may be uncomfortable and time consuming. We conducted a multicentre, randomized (1:1), assessor-blinded study in patients with peripheral neuropathic pain to assess tolerability of the capsaicin patch following topical lidocaine (4%) or oral tramadol (50 mg) pretreatment. The primary endpoint was the proportion of patients tolerating capsaicin patch application (ability to receive ≥90% of a 60-min application). Numeric Pain Rating Scale (NPRS) scores were assessed before, during and after treatment. Overall, 122 patients were included (61 per arm). The capsaicin patch was tolerated by 121 patients. Tolerability of the capsaicin patch was similar following pretreatment with lidocaine and tramadol. Following patch application, pain levels increased up to 55 min (change from baseline of 1.3 for lidocaine and 1.4 for tramadol). After patch removal, tramadol-treated patients experienced greater pain relief up to the end of day 1; in the evening, mean changes in NPRS scores from baseline were 0 for lidocaine and -1 for tramadol. Proportions of patients reporting increases of ≥2 NPRS points or >33% from baseline at one or more time point(s) on the day of treatment were similar between arms. Adverse event incidence was comparable between arms. Capsaicin 8% patch tolerability was similar in the two arms, with comparable results for most secondary endpoints. Tramadol given 30 min before patch application should be considered as an alternative pretreatment option in patients receiving capsaicin patch treatment. © 2014 The Authors. European Journal of Pain published by John Wiley & Sons Ltd on behalf of European Pain Federation - EFIC®.

Landscape heterogeneity controls growth variability of alder, willow, and birch shrubs in response to observed increases in temperature and snow

NASA Astrophysics Data System (ADS)

Tape, K. D.; Hallinger, M.; Buras, A.; Wilmking, M.

2013-12-01

Over the last decade, evidence has emerged for a circumarctic trend of increasing shrub cover in tundra regions. On the Alaskan tundra, repeat photography has shown spatial differences in shrub patch dynamics: since 1950, most patches expanded while some remained stable. In this study we explore the underpinnings of this landscape heterogeneity by sampling the three dominant shrubs of the Alaskan tundra--alder, willow and birch--and creating shrub ring width chronologies to determine the influence of climate variability on shrub growth. Shrubs of expanding patches of all three species grew at higher rates than shrubs of stable patches. Alder and willow shrubs in expanding patches exhibited mainly positive growth trends, while their counterparts in stable patches exhibited mainly negative growth trends. Birch shrub growth declined in expanding and stable patches. Alder and willow shrub growth rates and responses to climate were controlled more by soil characteristics than by their genus; expanding alder and willow shrubs showed significant positive correlations with spring and summer temperatures, whereas alder and willow shrubs of stable patches were negatively influenced by winter precipitation. The widely-scattered stable shrub patches sampled here are considered ';moist tussock tundra,' which covers 13.4% of the low arctic landscape. In moist tussock tundra, and presumably also wet tussock tundra, the negative influence of deeper snow on shrubs outweighed the positive influence of deeper snow on ground temperature and nutrient stocks articulated by the snow-shrub-microbe hypothesis. Thus, while shrubs of expanding patches have generally profited from warmer summers, shrubs of stable patches have suffered from increased soil moisture resulting from increased snowmelt water. These results underscore the spatial and temporal complexity in shrub-climate dynamics, which will require considerable finesse to appropriately integrate into modeling efforts.

Effect of Landscape Pattern on Insect Species Density within Urban Green Spaces in Beijing, China

PubMed Central

Su, Zhimin; Li, Xiaoma; Zhou, Weiqi; Ouyang, Zhiyun

2015-01-01

Urban green space is an important refuge of biodiversity in urban areas. Therefore, it is crucial to understand the relationship between the landscape pattern of green spaces and biodiversity to mitigate the negative effects of urbanization. In this study, we collected insects from 45 green patches in Beijing during July 2012 using suction sampling. The green patches were dominated by managed lawns, mixed with scattered trees and shrubs. We examined the effects of landscape pattern on insect species density using hierarchical partitioning analysis and partial least squares regression. The results of the hierarchical partitioning analysis indicated that five explanatory variables, i.e., patch area (with 19.9% independent effects), connectivity (13.9%), distance to nearest patch (13.8%), diversity for patch types (11.0%), and patch shape (8.3%), significantly contributed to insect species density. With the partial least squares regression model, we found species density was negatively related to patch area, shape, connectivity, diversity for patch types and proportion of impervious surface at the significance level of p < 0.05 and positively related to proportion of vegetated land. Regression tree analysis further showed that the highest species density was found in green patches with an area <500 m2. Our results indicated that improvement in habitat quality, such as patch area and connectivity that are typically thought to be important for conservation, did not actually increase species density. However, increasing compactness (low-edge) of patch shape and landscape composition did have the expected effect. Therefore, it is recommended that the composition of the surrounding landscape should be considered simultaneously with planned improvements in local habitat quality. PMID:25793897

Energy state affects exploratory behavior of tree sparrows in a group context under differential food-patch distributions.

PubMed

Lee, Ya-Fu; Kuo, Yen-Min; Chu, Wen-Chen

2016-01-01

When facing a novel situation, animals can retreat or leave to avoid risks, but will miss potential resources and opportunities. Alternatively they may reduce environmental uncertainty by exploration, while risking no energy rewards and exposure to hazards, and use the information retrieved for subsequent decision making. When exploring, however, animals may adopt different tactics according to individual states. We tested that energy states will affect exploratory behavior by experimenting with wild-caught untrained Eurasian tree sparrows ( Passer montanus ) in fasted or fed states exploring in a novel space with hidden food supply in different patch distribution patterns. Our data revealed that fasted sparrows risked being earlier explorers more often, initiated more exploratory bouts before patches were found, and stayed longer on the ground under both patch patterns. Fasted sparrows discovered more patches and consumed more food than fed sparrows in dispersed, but not necessary so in clumped, patch patterns; whereas fed birds also increased patch finding to a certain level in dispersed patterns. Sparrows of both energy states, however, did not differ in feeding rates in either patch pattern. Exploratory behavior of tree sparrows is state-dependent, which supports our prediction that birds with an energy shortage will be risk-prone and explore more readily. Our study also indicates a game nature of tree sparrow exploratory behavior in a group context when explorers are in different energy states and are exposed to different patch distributions. Birds of lower energy state adopting an active exploring tactic may be favored by obtaining higher energy gains in dispersed patch patterns with lower patch richness. More satiated birds, however, achieved a similar feeding rate by lowered exposure time.

Low-dose levonorgestrel and ethinyl estradiol patch and pill: a randomized controlled trial.

PubMed

Kaunitz, Andrew M; Portman, David; Westhoff, Carolyn L; Archer, David F; Mishell, Daniel R; Rubin, Arkady; Foegh, Marie

2014-02-01

To compare a new low-dose levonorgestrel and ethinyl estradiol contraceptive patch (Patch) with a combination oral contraceptive (Pill; 100 micrograms levonorgestrel, 20 micrograms ethinyl estradiol) regarding efficacy, safety, compliance, and unscheduled uterine bleeding. Women (17-40 years; body mass index 16-60) were randomized in a 3:1 ratio to one of two groups: Patch only (13 cycles) or Pill (six cycles) followed by Patch (seven cycles). Investigators evaluated adverse events during cycles 2, 4, 6, 9, and 13. Participants recorded drug administration and uterine bleeding on daily diary cards. Compliance was assessed by measuring levonorgestrel and ethinyl estradiol plasma levels. Pearl Index (pregnancies per 100 woman-years) was calculated to evaluate efficacy. Participants (N=1,504) were randomized to Patch (n=1,129) or Pill (n=375). Approximately 30% were obese, more than 40% were racial or ethnic minorities, and more than 55% were new users of hormonal contraceptives. Laboratory-verified noncompliance (undetectable plasma drug levels) was 11% of Patch and 12.6% of Pill users at cycle 6. Pearl Indices (95% confidence intervals) for the intention-to-treat population (cycles 1-6) were 4.45 (2.34-6.57) for Patch and 4.02 (0.50-7.53) for Pill; excluding laboratory-verified noncompliant participants, Pearl Indices were 2.82 (0.98-4.67) for Patch and 3.80 (0.08-7.52) for Pill (differences not statistically significant). Incidence of unscheduled bleeding and incidence and severity of adverse events were similar for both contraceptives (no statistically significant difference). Efficacy and safety of the new contraceptive Patch are comparable to those of a Pill. Laboratory-verified noncompliance and bleeding profile are similar between the two treatments. The Patch was well tolerated. ClinicalTrials.gov, www.clinicaltrials.gov, NCT01181479. I.

Randomized, double-blind, placebo-controlled trial using lidocaine patch 5% in traumatic rib fractures.

PubMed

Ingalls, Nichole K; Horton, Zachary A; Bettendorf, Matthew; Frye, Ira; Rodriguez, Carlos

2010-02-01

The lidocaine patch 5% was developed to treat postherpetic neuralgia. Anecdotal experience at our institution suggests the lidocaine patch 5% decreases narcotic usage in patients with traumatic rib fractures. This trial was developed to define the patch's efficacy. Patients with rib fractures admitted to the trauma service at our Level I trauma center were enrolled and randomized in a 1 to 1 double-blind manner to receive a lidocaine patch 5% or placebo patch. Fifty-eight patients who met the inclusion criteria were enrolled from January 2007 to August 2008. Demographic and clinical information were recorded. The primary outcomes variable was total narcotic use, analyzed using the 1-tailed Mann-Whitney test. The secondary outcomes variables included non-narcotic pain medication, average pain score, pulmonary complications, and length of stay. Significance was defined based on a 1-sided test for the primary outcome and 2-sided tests for other comparisons, at p < 0.05. Thirty-three patients received the lidocaine patch 5% and 25 received the placebo patch. There were no significant differences in age, number of rib fractures, gender, trauma mechanism, preinjury lung disease, smoking history, percent of current smokers, and need for placement of chest tube between the lidocaine patch 5% and placebo groups. There was no difference between the lidocaine patch 5% and placebo groups, respectively, with regard to total IV narcotic usage: median, 0.23 units versus 0.26 units; total oral narcotics: median, 4 units versus 7 units; pain score: 5.6 +/- 0.4 versus 6.0 +/- 0.3 (mean +/- SEM); length of stay: 7.8 +/- 1.1 versus 6.2 +/- 0.7; or percentage of patients with pulmonary complications: 72.7% versus 72.0%. The lidocaine patch 5% does not significantly improve pain control in polytrauma patients with traumatic rib fractures.

Effect of landscape pattern on insect species density within urban green spaces in Beijing, China.

PubMed

Su, Zhimin; Li, Xiaoma; Zhou, Weiqi; Ouyang, Zhiyun

2015-01-01

Urban green space is an important refuge of biodiversity in urban areas. Therefore, it is crucial to understand the relationship between the landscape pattern of green spaces and biodiversity to mitigate the negative effects of urbanization. In this study, we collected insects from 45 green patches in Beijing during July 2012 using suction sampling. The green patches were dominated by managed lawns, mixed with scattered trees and shrubs. We examined the effects of landscape pattern on insect species density using hierarchical partitioning analysis and partial least squares regression. The results of the hierarchical partitioning analysis indicated that five explanatory variables, i.e., patch area (with 19.9% independent effects), connectivity (13.9%), distance to nearest patch (13.8%), diversity for patch types (11.0%), and patch shape (8.3%), significantly contributed to insect species density. With the partial least squares regression model, we found species density was negatively related to patch area, shape, connectivity, diversity for patch types and proportion of impervious surface at the significance level of p < 0.05 and positively related to proportion of vegetated land. Regression tree analysis further showed that the highest species density was found in green patches with an area <500 m2. Our results indicated that improvement in habitat quality, such as patch area and connectivity that are typically thought to be important for conservation, did not actually increase species density. However, increasing compactness (low-edge) of patch shape and landscape composition did have the expected effect. Therefore, it is recommended that the composition of the surrounding landscape should be considered simultaneously with planned improvements in local habitat quality.

Patch-augmented rotator cuff repair: influence of the patch fixation technique on primary biomechanical stability.

PubMed

Jung, Christian; Spreiter, Gregor; Audigé, Laurent; Ferguson, Stephen J; Flury, Matthias

2016-05-01

There is an ongoing debate about the potential of patch augmentation to improve biomechanical stability and healing associated with rotator cuff repair. The biomechanical properties of three different patch-augmented rotator cuff repair techniques were assessed in vitro and compared with a standard repair. Dermal collagen patch augmentation may increase the primary stability and strength of the repaired tendon in vitro, depending on the technique used for patch application. Forty cadaveric sheep shoulders with dissected infraspinatus tendons were randomized into four groups (n = 10/group) for tendon repair using a knotless double-row suture anchor technique. A xenologous dermal extracellular matrix patch was used for augmentation in the three test groups using an "integrated", "cover", or "hybrid" technique. Tendons were preconditioned, cyclically loaded from 10 to 30 N at 1 Hz, and then loaded monotonically to failure. Biomechanical properties and the mode of failure were evaluated. Patch augmentation significantly increased the maximum load at failure by 61 % in the "cover" technique test group (225.8 N) and 51 % in the "hybrid" technique test group (211.4 N) compared with the non-augmented control group (140.2 N) (P ≤ 0.015). For the test group with "integrated" patch augmentation, the load at failure was 28 % lower (101.6 N) compared with the control group (P = 0.043). There was no significant difference in initial and linear stiffness among the four experimental groups. The most common mode of failure was tendon pullout. No anchor dislocation, patch disruption or knot breakage was observed. Additional patch augmentation with a collagen patch influences the biomechanical properties of a rotator cuff repair in a cadaveric sheep model. Primary repair stability can be significantly improved depending on the augmentation technique.

Localization and Tracking of Submerged Phytoplankton Bloom Patches by an Autonomous Underwater Vehicle

NASA Astrophysics Data System (ADS)

Godin, M. A.; Ryan, J. P.; Zhang, Y.; Bellingham, J. G.

2012-12-01

Observing plankton in their drifting frame of reference permits effective studies of marine ecology from the perspective of microscopic life itself. By minimizing variation caused simply by advection, observations in a plankton-tracking frame of reference focus measurement capabilities on the processes that influence the life history of populations. Further, the patchy nature of plankton populations motivates use of sensor data in real-time to resolve patch boundaries and adapt observing resources accordingly. We have developed capabilities for population-centric plankton observation and sampling by autonomous underwater vehicles (AUVs). Our focus has been on phytoplankton populations, both because of their ecological significance - as the core of the oceanic food web and yet potentially harmful under certain bloom conditions, as well as the accessibility of their signal to simple optical sensing. During the first field deployment of these capabilities in 2010, we tracked a phytoplankton patch containing toxigenic diatoms and found that their toxicity correlated with exposure to resuspended sediments. However, this first deployment was labor intensive as the AUV drove in a pre-programmed pattern centered around a patch-marking drifter; it required a boat deployment of the patch-marking drifter and required full-time operators to periodically estimate of the position of the patch with respect to the drifter and adjust the AUV path accordingly. In subsequent field experiments during 2011 and 2012, the Tethys-class long-range AUVs ran fully autonomous patch tracking algorithms which detected phytoplankton patches and continually updated estimates of each patch center by driving adaptive patterns through the patch. Iterations of the algorithm were generated to overcome the challenges of tracking advecting and evolving patches while minimizing human involvement in vehicle control. Such fully autonomous monitoring will be necessary to perform long-term in-situ observation of the full growth and decay cycle of bloom patches. Doing so will enhance our understanding of the temporal and spatial dynamics of bloom patches and the observable conditions that lead to bloom formation, ultimately improving our ability to predict the evolution of harmful algal blooms (HABs) and provide warnings for the fishing and tourism industries.

Cost-effectiveness analysis of a new 8% capsaicin patch compared to existing therapies for postherpetic neuralgia.

PubMed

Armstrong, Edward P; Malone, Daniel C; McCarberg, Bill; Panarites, Christopher J; Pham, Sissi V

2011-05-01

The purpose of this study was to compare the cost effectiveness of a new 8% capsaicin patch, compared to the current treatments for postherpetic neuralgia (PHN), including tricyclic antidepressants (TCAs), topical lidocaine patches, duloxetine, gabapentin, and pregabalin. A 1-year Markov model was constructed for PHN with monthly cycles, including dose titration and management of adverse events. The perspective of the analysis was from a payer perspective, managed-care organization. Clinical trials were used to determine the proportion of patients achieving at least a 30% improvement in PHN pain, the efficacy parameter. The outcome was cost per quality-adjusted life-year (QALY); second-order probabilistic sensitivity analyses were conducted. The effectiveness results indicated that 8% capsaicin patch and topical lidocaine patch were significantly more effective than the oral PHN products. TCAs were least costly and significantly less costly than duloxetine, pregabalin, topical lidocaine patch, 8% capsaicin patch, but not gabapentin. The incremental cost-effectiveness ratio for the 8% capsaicin patch overlapped with the topical lidocaine patch and was within the accepted threshold of cost per QALY gained compared to TCAs, duloxetine, gabapentin, and pregablin. The frequency of the 8% capsaicin patch retreatment assumption significantly impacts its cost-effectiveness results. There are several limitations to this analysis. Since no head-to-head studies were identified, this model used inputs from multiple clinical trials. Also, a last observation carried forward process was assumed to have continued for the duration of the model. Additionally, the trials with duloxetine may have over-predicted its efficacy in PHN. Although a 30% improvement in pain is often an endpoint in clinical trials, some patients may require greater or less improvement in pain to be considered a clinical success. The effectiveness results demonstrated that 8% capsaicin and topical lidocaine patches had significantly higher effectiveness rates than the oral agents used to treat PHN. In addition, this cost-effectiveness analysis found that the 8% capsaicin patch was similar to topical lidocaine patch and within an accepted cost per QALY gained threshold compared to the oral products.

Remote sensing-based landscape indicators for the evaluation of threatened-bird habitats in a tropical forest.

PubMed

Singh, Minerva; Tokola, Timo; Hou, Zhengyang; Notarnicola, Claudia

2017-07-01

Avian species persistence in a forest patch is strongly related to the degree of isolation and size of a forest patch and the vegetation structure within a patch and its matrix are important predictors of bird habitat suitability. A combination of space-borne optical (Landsat), ALOS-PALSAR (radar), and airborne Light Detection and Ranging (LiDAR) data was used for assessing variation in forest structure across forest patches that had undergone different levels of forest degradation in a logged forest-agricultural landscape in Southern Laos. The efficacy of different remote sensing (RS) data sources in distinguishing forest patches that had different seizes, configurations, and vegetation structure was examined. These data were found to be sensitive to the varying levels of degradation of the different patch categories. Additionally, the role of local scale forest structure variables (characterized using the different RS data and patch area) and landscape variables (characterized by distance from different forest patches) in influencing habitat preferences of International Union for Conservation of Nature (IUCN) Red listed birds found in the study area was examined. A machine learning algorithm, MaxEnt, was used in conjunction with these data and field collected geographical locations of the avian species to identify the factors influencing habitat preference of the different bird species and their suitable habitats. Results show that distance from different forest patches played a more important role in influencing habitat suitability for the different avian species than local scale factors related to vegetation structure and health. In addition to distance from forest patches, LiDAR-derived forest structure and Landsat-derived spectral variables were important determinants of avian habitat preference. The models derived using MaxEnt were used to create an overall habitat suitability map (HSM) which mapped the most suitable habitat patches for sustaining all the avian species. This work also provides insight that retention of forest patches, including degraded and isolated forest patches in addition to large contiguous forest patches, can facilitate bird species retention within tropical agricultural landscapes. It also demonstrates the effective use of RS data in distinguishing between forests that have undergone varying levels of degradation and identifying the habitat preferences of different bird species. Practical conservation management planning endeavors can use such data for both landscape scale monitoring and habitat mapping.

An experimental test of the habitat-amount hypothesis for saproxylic beetles in a forested region.

PubMed

Seibold, Sebastian; Bässler, Claus; Brandl, Roland; Fahrig, Lenore; Förster, Bernhard; Heurich, Marco; Hothorn, Torsten; Scheipl, Fabian; Thorn, Simon; Müller, Jörg

2017-06-01

The habitat-amount hypothesis challenges traditional concepts that explain species richness within habitats, such as the habitat-patch hypothesis, where species number is a function of patch size and patch isolation. It posits that effects of patch size and patch isolation are driven by effects of sample area, and thus that the number of species at a site is basically a function of the total habitat amount surrounding this site. We tested the habitat-amount hypothesis for saproxylic beetles and their habitat of dead wood by using an experiment comprising 190 plots with manipulated patch sizes situated in a forested region with a high variation in habitat amount (i.e., density of dead trees in the surrounding landscape). Although dead wood is a spatio-temporally dynamic habitat, saproxylic insects have life cycles shorter than the time needed for habitat turnover and they closely track their resource. Patch size was manipulated by adding various amounts of downed dead wood to the plots (~800 m³ in total); dead trees in the surrounding landscape (~240 km 2 ) were identified using airborne laser scanning (light detection and ranging). Over 3 yr, 477 saproxylic species (101,416 individuals) were recorded. Considering 20-1,000 m radii around the patches, local landscapes were identified as having a radius of 40-120 m. Both patch size and habitat amount in the local landscapes independently affected species numbers without a significant interaction effect, hence refuting the island effect. Species accumulation curves relative to cumulative patch size were not consistent with either the habitat-patch hypothesis or the habitat-amount hypothesis: several small dead-wood patches held more species than a single large patch with an amount of dead wood equal to the sum of that of the small patches. Our results indicate that conservation of saproxylic beetles in forested regions should primarily focus on increasing the overall amount of dead wood without considering its spatial arrangement. This means dead wood should be added wherever possible including in local landscapes with low or high dead-wood amounts. For species that have disappeared from most forests owing to anthropogenic habitat degradation, this should, however, be complemented by specific conservation measures pursued within their extant distributional ranges. © 2017 by the Ecological Society of America.

Tolerability of the capsaicin 8% patch following pretreatment with lidocaine or tramadol in patients with peripheral neuropathic pain: A multicentre, randomized, assessor-blinded study

PubMed Central

Jensen, TS; Høye, K; Fricová, J; Vanelderen, P; Ernault, E; Siciliano, T; Marques, S

2014-01-01

Background Application of the capsaicin 8% patch is associated with treatment-related discomfort. Consequently, pretreatment for 60 min with anaesthetic cream is recommended; however, this may be uncomfortable and time consuming. Methods We conducted a multicentre, randomized (1:1), assessor-blinded study in patients with peripheral neuropathic pain to assess tolerability of the capsaicin patch following topical lidocaine (4%) or oral tramadol (50 mg) pretreatment. The primary endpoint was the proportion of patients tolerating capsaicin patch application (ability to receive ≥90% of a 60-min application). Numeric Pain Rating Scale (NPRS) scores were assessed before, during and after treatment. Results Overall, 122 patients were included (61 per arm). The capsaicin patch was tolerated by 121 patients. Tolerability of the capsaicin patch was similar following pretreatment with lidocaine and tramadol. Following patch application, pain levels increased up to 55 min (change from baseline of 1.3 for lidocaine and 1.4 for tramadol). After patch removal, tramadol-treated patients experienced greater pain relief up to the end of day 1; in the evening, mean changes in NPRS scores from baseline were 0 for lidocaine and −1 for tramadol. Proportions of patients reporting increases of ≥2 NPRS points or >33% from baseline at one or more time point(s) on the day of treatment were similar between arms. Adverse event incidence was comparable between arms. Conclusions Capsaicin 8% patch tolerability was similar in the two arms, with comparable results for most secondary endpoints. Tramadol given 30 min before patch application should be considered as an alternative pretreatment option in patients receiving capsaicin patch treatment. What's already known about this topic? Application of topical capsaicin, a treatment for peripheral neuropathic pain conditions associated with allodynia, can cause painful discomfort. Therefore, a 60-min application of local anaesthetic cream before capsaicin 8% patch treatment was originally recommended. What does this study add? Oral analgesic pretreatment may reduce overall capsaicin patch treatment time and potential unpleasantness associated with applying a topical agent to an allodynic area. Based on LIFT data showing similar tolerability to capsaicin patch regardless of pretreatment method, the European Medicines Agency has issued a type II variation stating: treatment area may be pretreated with a topical anaesthetic or an oral analgesic may be given prior to patch application. PMID:24664539

Hierarchical Multi-atlas Label Fusion with Multi-scale Feature Representation and Label-specific Patch Partition

PubMed Central

Wu, Guorong; Kim, Minjeong; Sanroma, Gerard; Wang, Qian; Munsell, Brent C.; Shen, Dinggang

2014-01-01

Multi-atlas patch-based label fusion methods have been successfully used to improve segmentation accuracy in many important medical image analysis applications. In general, to achieve label fusion a single target image is first registered to several atlas images, after registration a label is assigned to each target point in the target image by determining the similarity between the underlying target image patch (centered at the target point) and the aligned image patch in each atlas image. To achieve the highest level of accuracy during the label fusion process it’s critical the chosen patch similarity measurement accurately captures the tissue/shape appearance of the anatomical structure. One major limitation of existing state-of-the-art label fusion methods is that they often apply a fixed size image patch throughout the entire label fusion procedure. Doing so may severely affect the fidelity of the patch similarity measurement, which in turn may not adequately capture complex tissue appearance patterns expressed by the anatomical structure. To address this limitation, we advance state-of-the-art by adding three new label fusion contributions: First, each image patch now characterized by a multi-scale feature representation that encodes both local and semi-local image information. Doing so will increase the accuracy of the patch-based similarity measurement. Second, to limit the possibility of the patch-based similarity measurement being wrongly guided by the presence of multiple anatomical structures in the same image patch, each atlas image patch is further partitioned into a set of label-specific partial image patches according to the existing labels. Since image information has now been semantically divided into different patterns, these new label-specific atlas patches make the label fusion process more specific and flexible. Lastly, in order to correct target points that are mislabeled during label fusion, a hierarchically approach is used to improve the label fusion results. In particular, a coarse-to-fine iterative label fusion approach is used that gradually reduces the patch size. To evaluate the accuracy of our label fusion approach, the proposed method was used to segment the hippocampus in the ADNI dataset and 7.0 tesla MR images, sub-cortical regions in LONI LBPA40 dataset, mid-brain regions in SATA dataset from MICCAI 2013 segmentation challenge, and a set of key internal gray matter structures in IXI dataset. In all experiments, the segmentation results of the proposed hierarchical label fusion method with multi-scale feature representations and label-specific atlas patches are more accurate than several well-known state-of-the-art label fusion methods. PMID:25463474

Results on asymptotic behaviour for discrete, two-patch metapopulations with density-dependent selection

Treesearch

James F. Selgrade; James H. Roberds

2005-01-01

A 4-dimensional system of nonlinear difference equations tracking allele frequencies and population sizes for a two-patch metapopulation model is studied. This system describes intergenerational changes brought about by density-dependent selection within patches and moderated by the effects of migration between patches. To determine conditions which result in similar...

Using an index of habitat patch proximity for landscape design

Treesearch

Eric J. Gustafson; George R. Parker

1994-01-01

A proximity index (PX) inspired by island biogeography theory is described which quantifies the spatial context of a habitat patch in relation to its neighbors. The index distinguishes sparse distributions of small habitat patches from clusters of large patches. An evaluation of the relationship between PX and variation in the spatial characteristics of clusters of...

Functionalized patchy particles using colloidal lenses

NASA Astrophysics Data System (ADS)

Middleton, Christine

2014-03-01

Colloidal assembly had been limited by the isotropic, nonspecific nature of interactions between spherical colloidal particles. By giving particles patches functionalized with single stranded DNA, these interactions can be made both directional and specific. We create patchy particles by adding patches to spherical emulsion droplets using the depletion interaction. First we make polystyrene particles in the shape of contact lenses to be the patches. The lenses are functionalized with single stranded DNA on their convex side. Then we put the lenses on the surface of oil emulsion droplets using the depletion interaction, creating a patch (or multiple patches) on the surface of each emulsion droplet. The emulsion droplets can now interact with each other in a specific, directional way through DNA functionalized patches.

Adult fruit fly attraction to larvae biases experience and mediates social learning.

PubMed

Durisko, Zachary; Anderson, Blake; Dukas, Reuven

2014-04-01

We investigated whether adult fruit flies (Drosophila melanogaster) use cues of larvae as social information in their food patch choice decisions. Adult male and female fruit flies showed attraction to odours emanating from foraging larvae, and females preferred to lay eggs on food patches occupied by larvae over similar unoccupied patches. Females learned and subsequently preferred to lay eggs at patches with novel flavours previously associated with feeding larvae over patches with novel flavours previously associated with no larvae. However, when we controlled for the duration of exposure to each flavoured patch, females no longer preferred the flavour previously associated with feeding larvae. This suggests that social learning in this context is indirect, as a result of strong social attraction biasing experience.

Multi-Physics MRI-Based Two-Layer Fluid-Structure Interaction Anisotropic Models of Human Right and Left Ventricles with Different Patch Materials: Cardiac Function Assessment and Mechanical Stress Analysis

PubMed Central

Tang, Dalin; Yang, Chun; Geva, Tal; Gaudette, Glenn; del Nido, Pedro J.

2011-01-01

Multi-physics right and left ventricle (RV/LV) fluid-structure interaction (FSI) models were introduced to perform mechanical stress analysis and evaluate the effect of patch materials on RV function. The FSI models included three different patch materials (Dacron scaffold, treated pericardium, and contracting myocardium), two-layer construction, fiber orientation, and active anisotropic material properties. The models were constructed based on cardiac magnetic resonance (CMR) images acquired from a patient with severe RV dilatation and solved by ADINA. Our results indicate that the patch model with contracting myocardium leads to decreased stress level in the patch area, improved RV function and patch area contractility. PMID:21765559

Potential toxicity and affinity of triphenylmethane dye malachite green to lysozyme.

PubMed

Ding, Fei; Li, Xiu-Nan; Diao, Jian-Xiong; Sun, Ye; Zhang, Li; Ma, Lin; Yang, Xin-Ling; Zhang, Li; Sun, Ying

2012-04-01

Malachite green is a triphenylmethane dye that is used extensively in many industrial and aquacultural processes, generating environmental concerns and health problems to human being. In this contribution, the complexation between lysozyme and malachite green was verified by means of computer-aided molecular modeling, steady state and time-resolved fluorescence, and circular dichroism (CD) approaches. The precise binding patch of malachite green in lysozyme has been identified from molecular modeling and ANS displacement, Trp-62, Trp-63, and Trp-108 residues of lysozyme were earmarked to possess high-affinity for this dye, the principal forces in the lysozyme-malachite green adduct are hydrophobic and π-π interactions. Steady state fluorescence proclaimed the complex of malachite green with lysozyme yields quenching through static type, which substantiates time-resolved fluorescence measurements that lysozyme-malachite green conjugation formation has an affinity of 10(3)M(-1). Moreover, via molecular modeling and also CD data, we can safely arrive at a conclusion that the polypeptide chain of lysozyme partially destabilized upon complexation with malachite green. The data emerged here will help to further understand the toxicological action of malachite green in human body. Copyright © 2012 Elsevier Inc. All rights reserved.

Effect of surfactants on Ra-sHSPI - A small heat shock protein from the cattle tick Rhipicephalus annulatus

NASA Astrophysics Data System (ADS)

Siddiqi, Mohammad Khursheed; Shahein, Yasser E.; Hussein, Nahla; Khan, Rizwan H.

2016-09-01

Electrostatic interaction plays an important role in protein aggregation phenomenon. In this study, we have checked the effect of anionic - Sodium Dodecyl Sulfate (SDS) and cationic-Cetyltrimethyl Ammonium Bromide (CTAB) surfactant on aggregation behavior of Ra-sHSPI, a small heat shock protein purified from Rhipicephalus annulatus tick. To monitor the effect of these surfactants, we have employed several spectroscopic methods such as Rayleigh light scattering measurements, ANS (8-Anilinonaphthalene-1-sulfonic acid) fluorescence measurements, ThT (Thioflavin T) binding assays, Far-UV CD (Circular Dichroism) and dynamic light scattering measurements. In the presence of anionic surfactant-SDS, Ra-sHSPI forms amyloid fibrils, in contrast, no amyloid formation was observed in presence of cationic surfactant at low pH. Enhancement of ANS fluorescence intensity confirms the exposition of more hydrophobic patches during aggregation. ThT binding assay confirms the amyloid fibrillar nature of the SDS induced Ra-sHSPI aggregates and supported by PASTA 2.0 (prediction of amyloid structural aggregation) software. This study demonstrates the crucial role of charge during amyloid fibril formation at low pH in Ra-sHSPI.

Ultra-high field MRI for primate imaging using the travelling-wave concept.

PubMed

Mallow, Johannes; Herrmann, Tim; Kim, Kyoung-Nam; Stadler, Joerg; Mylius, Judith; Brosch, Michael; Bernarding, Johannes

2013-08-01

Ultra-high field (UHF) neuroimaging is usually conducted with volume transmit (Tx) and phased array receive (Rx) coils, both tightly enclosing the object. The travelling-wave (TW) concept allows a remote excitation offering more flexible experimental setups. To investigate the feasibility of primate MRI in horizontal UHF MRI, we first compared the distribution of the electromagnetic fields in an oil phantom and then verified the concept with an in vivo experiment. In the phantom experiments an in-house circularly polarized hybrid birdcage coil and a self-developed patch antenna were used for Tx and an eight-element phased array antenna for Rx. B1+ fields were calculated and measured for both approaches. For in vivo experiments the Rx part was replaced with an optimized three-element phased array head coil. The SAR was calculated using field simulation. In the phantom the field distribution was homogenous in a central volume of interest of about 10 cm diameter. The TW concept showed a slightly better homogeneity. Examination of a female crab-eating macaque led to homogeneous high-contrast images with a good delineation of anatomical details. The TW concept opens up a new approach for MRI of medium-sized animals in horizontal UHF scanners.

Linear Streptomyces plasmids form superhelical circles through interactions between their terminal proteins

PubMed Central

Tsai, Hsiu-Hui; Huang, Chih-Hung; Tessmer, Ingrid; Erie, Dorothy A.; Chen, Carton W.

2011-01-01

Linear chromosomes and linear plasmids of Streptomyces possess covalently bound terminal proteins (TPs) at the 5′ ends of their telomeres. These TPs are proposed to act as primers for DNA synthesis that patches the single-stranded gaps at the 3′ ends during replication. Most (‘archetypal’) Streptomyces TPs (designated Tpg) are highly conserved in size and sequence. In addition, there are a number of atypical TPs with heterologous sequences and sizes, one of which is Tpc that caps SCP1 plasmid of Streptomyces coelicolor. Interactions between the TPs on the linear Streptomyces replicons have been suggested by electrophoretic behaviors of TP-capped DNA and circular genetic maps of Streptomyces chromosomes. Using chemical cross-linking, we demonstrated intramolecular and intermolecular interactions in vivo between Tpgs, between Tpcs and between Tpg and Tpc. Interactions between the chromosomal and plasmid telomeres were also detected in vivo. The intramolecular telomere interactions produced negative superhelicity in the linear DNA, which was relaxed by topoisomerase I. Such intramolecular association between the TPs poses a post-replicational complication in the formation of a pseudo-dimeric structure that requires resolution by exchanging TPs or DNA. PMID:21109537

Using Ice Nucleating Particles to Enable Desublimation on Chilled Substrates

NASA Astrophysics Data System (ADS)

O'Brien, Julia; Failor, Kevin; Bisbano, Caitlin; Mulroe, Megan; Nath, Saurabh; Vinatzer, Boris; Boreyko, Jonathan

2017-11-01

On a subfreezing surface, nucleating embryos usually form as supercooled condensate that later freeze into ice, as opposed to desublimation. Ice nucleating particles (INPs) have been widely used to freeze existing water; however, nobody has studied how they might affect the initial mode of nucleation. Here, we show that INPs deposited on a substrate can switch the mode of embryo nucleation to desublimation, rather than supercooled condensation. Deposition was achieved by evaporating a water droplet containing INPs on a hydrophobic silicon wafer. A Peltier stage was used to cool the wafer down inside of a controlled humidity chamber, such that the desired set point temperature correlated with the dew point and onset of nucleation. Beneath a critical surface temperature, microscopy indicated that desublimation occurred on the circular patch of deposited INPs, compared to supercooled condensation outside the circle. The hydrophobic surface was then patterned with hydrophilic stripe arrays, which facilitated the deposition of stripes of INPs via the same evaporation method. The resulting array of desublimating ice stripes created dry zones free of condensation or frost in the intermediate areas, as the hygroscopic ice stripes served as overlapping humidity sinks.

76 FR 62148 - Title VI; Proposed Circular, Environmental Justice; Proposed Circular

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-06

...-0055] Title VI; Proposed Circular, Environmental Justice; Proposed Circular AGENCY: Federal Transit... the September 29, 2011, Federal Register Notices titled ``Title VI; Proposed Circular'' and... September 29, 2011, Federal Register Notices titled ``Title VI; Proposed Circular'' (76 FR 60593) and...

Influence of temperature on patch residence time in parasitoids: physiological and behavioural mechanisms

NASA Astrophysics Data System (ADS)

Moiroux, Joffrey; Abram, Paul K.; Louâpre, Philippe; Barrette, Maryse; Brodeur, Jacques; Boivin, Guy

2016-04-01

Patch time allocation has received much attention in the context of optimal foraging theory, including the effect of environmental variables. We investigated the direct role of temperature on patch time allocation by parasitoids through physiological and behavioural mechanisms and its indirect role via changes in sex allocation and behavioural defences of the hosts. We compared the influence of foraging temperature on patch residence time between an egg parasitoid, Trichogramma euproctidis, and an aphid parasitoid, Aphidius ervi. The latter attacks hosts that are able to actively defend themselves, and may thus indirectly influence patch time allocation of the parasitoid. Patch residence time decreased with an increase in temperature in both species. The increased activity levels with warming, as evidenced by the increase in walking speed, partially explained these variations, but other mechanisms were involved. In T. euproctidis, the ability to externally discriminate parasitised hosts decreased at low temperature, resulting in a longer patch residence time. Changes in sex allocation with temperature did not explain changes in patch time allocation in this species. For A. ervi, we observed that aphids frequently escaped at intermediate temperature and defended themselves aggressively at high temperature, but displayed few defence mechanisms at low temperature. These defensive behaviours resulted in a decreased patch residence time for the parasitoid and partly explained the fact that A. ervi remained for a shorter time at the intermediate and high temperatures than at the lowest temperature. Our results suggest that global warming may affect host-parasitoid interactions through complex mechanisms including both direct and indirect effects on parasitoid patch time allocation.

Catch and Patch: A Pipette-Based Approach for Automating Patch Clamp That Enables Cell Selection and Fast Compound Application.

PubMed

Danker, Timm; Braun, Franziska; Silbernagl, Nikole; Guenther, Elke

2016-03-01

Manual patch clamp, the gold standard of electrophysiology, represents a powerful and versatile toolbox to stimulate, modulate, and record ion channel activity from membrane fragments and whole cells. The electrophysiological readout can be combined with fluorescent or optogenetic methods and allows for ultrafast solution exchanges using specialized microfluidic tools. A hallmark of manual patch clamp is the intentional selection of individual cells for recording, often an essential prerequisite to generate meaningful data. So far, available automation solutions rely on random cell usage in the closed environment of a chip and thus sacrifice much of this versatility by design. To parallelize and automate the traditional patch clamp technique while perpetuating the full versatility of the method, we developed an approach to automation, which is based on active cell handling and targeted electrode placement rather than on random processes. This is achieved through an automated pipette positioning system, which guides the tips of recording pipettes with micrometer precision to a microfluidic cell handling device. Using a patch pipette array mounted on a conventional micromanipulator, our automated patch clamp process mimics the original manual patch clamp as closely as possible, yet achieving a configuration where recordings are obtained from many patch electrodes in parallel. In addition, our implementation is extensible by design to allow the easy integration of specialized equipment such as ultrafast compound application tools. The resulting system offers fully automated patch clamp on purposely selected cells and combines high-quality gigaseal recordings with solution switching in the millisecond timescale.

Effective Connectivity Reveals Largely Independent Parallel Networks of Face and Body Patches.

PubMed

Premereur, Elsie; Taubert, Jessica; Janssen, Peter; Vogels, Rufin; Vanduffel, Wim

2016-12-19

The primate brain processes objects in the ventral visual pathway. One object category, faces, is processed in a hierarchical network of interconnected areas along this pathway. It remains unknown whether such an interconnected network is specific for faces or whether there are similar networks for other object classes. For example, the primate inferotemporal cortex also contains a set of body-selective patches, adjacent to the face-selective patches, but it is not known whether these body-selective patches form a similar discretely connected network or whether cross-talk exists between the face- and body-processing systems. To address these questions, we combined fMRI with electrical microstimulation to determine the effective connectivity of fMRI-defined face and body patches. We found that microstimulation of face patches caused increased fMRI activation throughout the face-processing system; microstimulation of the body patches gave similar results restricted to the body-processing system. Critically, our results revealed largely segregated connectivity patterns for the body and face patches. These results suggest that face and body patches form two interconnected hierarchical networks that are largely separated within the monkey inferotemporal cortex. Only a restricted number of voxels were activated by stimulation of both the body and face patches. The latter regions may be important for the integration of face and body information. Our findings are not only essential to advance our understanding of the neural circuits that enable social cognition, but they also provide further insights into the organizing principles of the inferotemporal cortex. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of land mosaic composition and structure on patchy populations: the case of the water vole (Arvicola sapidus) in Mediterranean farmland.

PubMed

Pita, Ricardo; Mira, António; Beja, Pedro

2013-01-01

The ability of patchy populations to persist in human-dominated landscapes is often assessed using focal patch approaches, in which the local occurrence or abundance of a species is related to the properties of individual patches and the surrounding landscape context. However, useful additional insights could probably be gained through broader, mosaic-level approaches, whereby whole land mosaics with contrasting patch-network and matrix characteristics are the units of investigation. In this study we addressed this issue, analysing how the southern water vole (Arvicola sapidus) responds to variables describing patch-network and matrix properties within replicated Mediterranean farmland mosaics, across a gradient of agricultural intensification. Patch-network characteristics had a dominant effect, with the total amount of habitat positively influencing both the occurrence of water voles and the proportion of area occupied in land mosaics. The proportions of patches and area occupied by the species were positively influenced by mean patch size, and negatively so by patch isolation. Matrix effects were weak, although there was a tendency for a higher proportion of occupied patches in more intensive, irrigated agricultural landscapes, particularly during the dry season. In terms of conservation, results suggest that water voles may be able to cope well with, or even be favoured by, the on-going expansion of irrigated agriculture in Mediterranean dry-lands, provided that a number of patches of wet herbaceous vegetation are maintained within the farmland mosaic. Overall, our study suggests that the mosaic-level approach may provide a useful framework to understand the responses of patchy populations to land use change.

Landscape characteristics of disturbed shrubsteppe habitats in southwestern Idaho (USA)

USGS Publications Warehouse

Knick, Steven T.; Rotenberry, J.T.

1997-01-01

We compared 5 zones in shrubsteppe habitats of southwestern Idaho to determine the effect of differing disturbance combinations on landscapes that once shared historically similar disturbance regimes. The primary consequence of agriculture, wildfires, and extensive fires ignited by the military during training activities was loss of native shrubs from the landscape. Agriculture created large square blocks on the landscape, and the landscape contained fewer small patches and more large shrub patches than non-agricultural areas. In contrast, fires left a more fragmented landscape. Repeated fires did not change the distribution of patch sizes, but decreased the total area of remaining shrublands and increased the distance between remaining shrub patches that provide seed sources. Military training with tracked vehicles was associated with a landscape characterized by small, closely spaced, shrub patches. Our results support the general model hypothesized for conversion of shrublands to annual grasslands by disturbance. Larger shrub patches in our region, historically resistant to fire spread and large-scale fires because of a perennial bunchgrass understory, were more fragmented than small patches. Presence of cheatgrass (Bromus tectorum), an exotic annual, was positively related to landscape patchiness and negatively related to number of shrub cells. Thus, cheatgrass dominance can contribute to further fragmentation and loss of the shrub patch by facilitating spread of subsequent fires, carried by continuous fuels, through the patch. The synergistic processes of fragmentation of shrub patches by disturbance, invasion and subsequent dominance by exotic annuals, and fire are converting shrubsteppe in southwestern Idaho to a new state dominated by exotic annual grasslands and high fire frequencies.

Hierarchical spatial segregation of two Mediterranean vole species: the role of patch-network structure and matrix composition.

PubMed

Pita, Ricardo; Lambin, Xavier; Mira, António; Beja, Pedro

2016-09-01

According to ecological theory, the coexistence of competitors in patchy environments may be facilitated by hierarchical spatial segregation along axes of environmental variation, but empirical evidence is limited. Cabrera and water voles show a metapopulation-like structure in Mediterranean farmland, where they are known to segregate along space, habitat, and time axes within habitat patches. Here, we assess whether segregation also occurs among and within landscapes, and how this is influenced by patch-network and matrix composition. We surveyed 75 landscapes, each covering 78 ha, where we mapped all habitat patches potentially suitable for Cabrera and water voles, and the area effectively occupied by each species (extent of occupancy). The relatively large water vole tended to be the sole occupant of landscapes with high habitat amount but relatively low patch density (i.e., with a few large patches), and with a predominantly agricultural matrix, whereas landscapes with high patch density (i.e., many small patches) and low agricultural cover, tended to be occupied exclusively by the small Cabrera vole. The two species tended to co-occur in landscapes with intermediate patch-network and matrix characteristics, though their extents of occurrence were negatively correlated after controlling for environmental effects. In combination with our previous studies on the Cabrera-water vole system, these findings illustrated empirically the occurrence of hierarchical spatial segregation, ranging from within-patches to among-landscapes. Overall, our study suggests that recognizing the hierarchical nature of spatial segregation patterns and their major environmental drivers should enhance our understanding of species coexistence in patchy environments.

A procedure of landscape services assessment based on mosaics of patches and boundaries.

PubMed

Martín de Agar, Pilar; Ortega, Marta; de Pablo, Carlos L

2016-09-15

We develop a procedure for assessing the environmental value of landscape mosaics that simultaneously considers the values of land use patches and the values of the boundaries between them. These boundaries indicate the ecological interactions between the patches. A landscape mosaic is defined as a set of patches and the boundaries between them and corresponds to a spatial pattern of ecological interactions. The procedure is performed in two steps: (i) an environmental assessment of land use patches by means of a function that integrates values based on the goods and services the patches provide, and (ii) an environmental valuation of mosaics using a function that integrates the environmental values of their patches and the types and frequencies of the boundaries between them. This procedure allows us to measure how changes in land uses or in their spatial arrangement cause variations in the environmental value of landscape mosaics and therefore in that of the whole landscape. The procedure was tested in the Sierra Norte of Madrid (central Spain). The results show that the environmental values of the landscape depend not only on the land use patches but also on the values associated with the pattern of the boundaries within the mosaics. The results also highlight the importance of the boundaries between land use patches as determinants of the goods and services provided by the landscape. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bust economics: foragers choose high quality habitats in lean times

PubMed Central

Dickman, Christopher R.

2016-01-01

In environments where food resources are spatially variable and temporarily impoverished, consumers that encounter habitat patches with different food density should focus their foraging initially where food density is highest before they move to patches where food density is lower. Increasing missed opportunity costs should drive individuals progressively to patches with lower food density as resources in the initially high food density patches deplete. To test these expectations, we assessed the foraging decisions of two species of dasyurid marsupials (dunnarts: Sminthopsis hirtipes and S. youngsoni) during a deep drought, or bust period, in the Simpson Desert of central Australia. Dunnarts were allowed access to three patches containing different food densities using an interview chamber experiment. Both species exhibited clear preference for the high density over the lower food density patches as measured in total harvested resources. Similarly, when measuring the proportion of resources harvested within the patches, we observed a marginal preference for patches with initially high densities. Models analyzing behavioral choices at the population level found no differences in behavior between the two species, but models analyzing choices at the individual level uncovered some variation. We conclude that dunnarts can distinguish between habitat patches with different densities of food and preferentially exploit the most valuable. As our observations were made during bust conditions, experiments should be repeated during boom times to assess the foraging economics of dunnarts when environmental resources are high. PMID:26839751

Different morphologic formation patterns of dark patches in the black-spotted frog (Pelophylax nigromaculata) and the Asiatic toad (Bufo gargarizans).

PubMed

Guangming, Gan; Tao, Zhao; Chao, Li; Moyan, Zhao

2017-01-01

The black-spotted frog (Pelophylax nigromaculata) and Asiatic toad (Bufo gargarizans), two relatively distantly related species, live in different habitats with different adaptive dark patches. To explain the formation of dark patches, the distribution patterns of melanin granules were examined with light microscopy and transmission electron microscopy. Melanin granules were produced and gathered into the "cap" structures on top of the nuclei in most epidermal cells. The "cap" structures may play a role in forming the dorsal dark patches coupled with three-layer melanophores, which can give rise to three layers of interconnected melanin networks in the dorsal dermis in P. nigromaculata. Epidermal melanocytes are rare and do not have a definitive role in forming dorsal dark patches in either P. nigromaculata or B. gargarizans. In B. gargarizans, the dermal melanophores only give rise to a single-layered melanin network, which hardly results in dark patches in the dorsal skin. However, the dermal melanophores migrate twice and form into pseudostratified networks, leading to dark patch formation in the ventral skin in B. gargarizans. The melanin granules precisely coregulate dark patches in the dermis and/or epidermis in P. nigromaculata and B. gargarizans. The dark patch formation depends on melanin granules in the epidermis or/and dermis in P. nigromaculata and B. gargarizans.

Adolescents' experiences using the contraceptive patch versus pills.

PubMed

Sucato, Gina S; Land, Stephanie R; Murray, Pamela J; Cecchini, Reena; Gold, Melanie A

2011-08-01

To compare use of the weekly transdermal contraceptive patch (patch) with daily combined hormonal contraceptive pills (pills) in adolescents. Prospective longitudinal study of adolescents' self-selected (non-randomized) use of the patch or pills. Urban, university hospital-affiliated, adolescent outpatient clinic. 13-22-year-old female adolescents seeking hormonal contraception, 40 who chose the patch and 40 who chose pills. Data were collected via self-report on paper questionnaires at three-cycle intervals for a total of up to nine cycles. Method continuation, perfect use, method satisfaction, quality of life, and side effects, including menstrual changes and perceived mood changes. After nine cycles, 38% of patch users and 60% of pill users were still using the method they had chosen at enrollment. There were no significant differences between the groups in self-reported perfect use. No differences were found in quality of life or side effects. Both patch and pill users noted menses became lighter and more predictable and reported decreased depression prior to their menses; only the pill group reported improvement in premenstrual anger. Method satisfaction was similar in both groups except patch users were more likely to report that their contraceptive method improved normal daily activities. Despite apparent advantages of the patch over the pill, adolescents using both methods continue to face challenges achieving perfect and sustained contraceptive use. 2011 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Autonomous buckling of micrometer-sized lipid-protein membrane patches constructed by Dictyostelium discoideum.

PubMed

Takahashi, Kei; Toyota, Taro

2015-01-01

The cytosol of amoeba cells controls the membrane deformation during their motion in vivo. To investigate such ability of the cytosol of amoeba cell, Dictyostelium discoideum (Dictyostelium), in vitro, we used lipids extracted from Dictyostelium and commercially available phospholipids, and prepared substrate-supported lipid membrane patches on the micrometer scale by spin coating. We found that the spin coater holder, which has pores (pore size = 3.1 mm) of negative pressure to hold the cover glass induced the concave surface of the cover glass. The membrane lipid patches were formed at each position in the vicinity of the holder pores and their sizes were in the range of 2.7 to 3.2 × 10(4) μm(2). After addition of the cytosol extracted from Dictyostelium to the lipid membrane patches, through time-lapse observation with a confocal laser scanning fluorescence microscope, we observed an autonomous buckling of the Dictyostelium lipid patches and localized behaviours of proteins found within. The current method serves as the novel technique for the preparation of film patches in which the positions of patches are controlled by the holder pores without fabricating, modifying, and arranging the chemical properties of the solution components of lipids. The findings imply that lipid-binding proteins in the cytosol were adsorbed and accumulated within the Dictyostelium lipid patches, inducing the transformation of the cell-sized patch.

Spatial and temporal variation in sponge spicule patches at Station M, northeast Pacific.

PubMed

Laguionie-Marchais, C; Kuhnz, L A; Huffard, C L; Ruhl, H A; Smith, K L

Changes in habitat-forming organisms can have complex consequences for associated species. Sessile epibenthic glass "plate" sponges (Porifera: Hexactinellida) are conspicuous inhabitants of soft-sediment abyssal areas and their siliceous spicules create persistent spicule patches on the seafloor. Sponge spicule patch density, spatial dispersion, and percent cover were examined over a seven-year period (2006-2013) using remotely operated vehicle videos from Station M in the abyssal northeast Pacific (50˚00N, 123˚00W, ~4,000 m depth). There was an apparent large increase in newly dead plate sponges in February 2007 compared with December 2006, with this trend continuing through June 2007 (mean 0.03 % cover increasing to 0.33 %). A second increase in mean percent cover of dead plate sponges occurred from May 2011 (0.24 %) through June 2012 (0.60 %). Among the 28 megafaunal taxa occurring in association with the patches, the distributions of three taxa [two sponge taxa (Porifera) and brittle stars (Ophiuroidea)] suggested selectivity for the sponge spicule patches. The community structure of visible megafauna within sponge spicule patches was different when compared with that outside the patches suggesting that the sponges, after death, provide preferred habitat patches for certain benthic megafauna. These findings indicate that sponge spicule patches contribute to habitat heterogeneity in space and time.

Birth control - slow release methods

MedlinePlus

Contraception - slow-release hormonal methods; Progestin implants; Progestin injections; Skin patch; Vaginal ring ... might want to consider a different birth control method. SKIN PATCH The skin patch is placed on ...

Landscape and patch-level factors influence bird communities in an urbanized tropical island

Treesearch

Marcela Suarez-Rubio; John R. Thomlinson

2009-01-01

As human population continues to increase and intensification of human land use escalates, it is important to address the role of urban forest patches in supporting bird communities. We related bird species richness and community assemblage to landscape- and patch- level factors in 40 forest patches in the densely populated metropolitan area of San Juan, Puerto Rico....

Immunosuppressive and Anti-Inflammatory Effects of Nicotine Administered by Patch in an Animal Model

PubMed Central

Kalra, Roma; Singh, Shashi P.; Pena-Philippides, Juan C.; Langley, Raymond J.; Razani-Boroujerdi, Seddigheh; Sopori, Mohan L.

2004-01-01

To study the immunological effects of nicotine, there are several rodent models for chronic nicotine administration. These models include subcutaneously implanted miniosmotic pumps, nicotine-spiked drinking water, and self-administration via jugular cannulae. Administration of nicotine via these routes affects the immune system. Smokers frequently use nicotine patches to quit smoking, and the immunological effects of nicotine patches are largely unknown. To determine whether the nicotine patch affects the immune system, nicotine patches were affixed daily onto the backs of Lewis rats for 3 to 4 weeks. The patches efficiently raised the levels of nicotine and cotinine in serum and strongly inhibited the antibody-forming cell response of spleen cells to sheep red blood cells. The nicotine patch also suppressed the concanavalin A-induced T-cell proliferation and mobilization of intracellular Ca2+ by spleen cells, as well as the fever response of animals to subcutaneous administration of turpentine. Moreover, immunosuppression was associated with chronic activation of protein tyrosine kinase and phospholipase C-γ1 activities. Thus, in this animal model of nicotine administration, the nicotine patch efficiently raises the levels of nicotine and cotinine in serum and impairs both the immune and inflammatory responses. PMID:15138183

Use of rivastigmine transdermal patch in the treatment of Alzheimer's disease.

PubMed

Winblad, Bengt; Machado, João Carlos

2008-12-01

Cholinesterase inhibitors such as rivastigmine and donepezil exhibit a dose-response relationship, with higher doses of the drugs demonstrating greater efficacy. Transdermal patches provide smooth continuous drug delivery, with the potential to offer efficacious levels of drug exposure while avoiding the peaks and troughs associated with side effects. As a small, lipophilic and hydrophilic molecule, rivastigmine (C14H22N2O2) is chemically well-suited to transdermal delivery. The technology underlying the rivastigmine patch allows it to be discreetly small and thin. The target dose 9.5 mg/24 h rivastigmine patch has a diameter of just 3.5 cm and a surface area of 10 cm2. A large randomized controlled trial has demonstrated that the target dose 9.5 mg/24 h rivastigmine patch provided similar efficacy to the highest rivastigmine capsule doses, yet with three times fewer reports of nausea and vomiting. Thus, the rivastigmine patch enables quick and easy access to high dose efficacy. The skin tolerability profile is good, and the patch has demonstrated excellent adhesion. The apparent success of rivastigmine patch, in terms of clinical utility and patient acceptability, suggests that it may mark the next generation of dementia treatment.

A pliable electroporation patch (ep-Patch) for efficient delivery of nucleic acid molecules into animal tissues with irregular surface shapes.

PubMed

Wei, Zewen; Huang, Yuanyu; Zhao, Deyao; Hu, Zhiyuan; Li, Zhihong; Liang, Zicai

2015-01-05

Delivery of nucleic acids into animal tissues by electroporation is an appealing approach for various types of gene therapy, but efficiency of existing methodsis not satisfactory. Here we present the validation of novel electroporation patch (ep-Patch) for efficient delivery of DNA and siRNA into mouse tissues. Using micromachining technology, closely spaced gold electrodes were made on the pliable parylene substrate to form a patch-like electroporation metrics. It enabled large coverage of the target tissues and close surface contact between the tissues and electrodes, thus providing a uniform electric field to deliver nucleic acids into tissues, even beneath intact skin. Using this ep-Patch for efficiently delivery of both DNA and siRNA, non-invasive electroporation of healthy mouse muscle tissue was successfully achieved. Delivery of these nucleic acids was performed to intact tumors with satisfactory results. Silencing of tumor genes using the ep-Patch was also demonstrated on mice. This pliable electroporation patch method constitutes a novel way of in vivo delivery of siRNA and DNA to certain tissues or organs to circumvent the disadvantages of existing methodologies for in vivo delivery of nucleic acid molecules.

Development of a self-stressing NiTiNb shape memory alloy (SMA)/fiber reinforced polymer (FRP) patch

NASA Astrophysics Data System (ADS)

El-Tahan, M.; Dawood, M.; Song, G.

2015-06-01

The objective of this research is to develop a self-stressing patch using a combination of shape memory alloys (SMAs) and fiber reinforced polymer (FRP) composites. Prestressed carbon FRP patches are emerging as a promising alternative to traditional methods to repair cracked steel structures and civil infrastructure. However, prestressing these patches typically requires heavy and complex fixtures, which is impractical in many applications. This paper presents a new approach in which the prestressing force is applied by restraining the shape memory effect of NiTiNb SMA wires. The wires are subsequently embedded in an FRP overlay patch. This method overcomes the practical challenges associated with conventional prestressing. This paper presents the conceptual development of the self-stressing patch with the support of experimental observations. The bond between the SMA wires and the FRP is evaluated using pull-out tests. The paper concludes with an experimental study that evaluates the patch response during activation subsequent monotonic tensile loading. The results demonstrate that the self-stressing patch with NiTiNb SMA is capable of generating a significant prestressing force with minimal tool and labor requirements.

Modelling recolonization of second-growth forest stands by the north american red squirrel Tamiasciurus hudsonicus.

PubMed

Nyquist, B; Tyson, R; Larsen, K

2007-05-01

In this paper, we present a model for source-sink population dynamics where the locations of source and sink habitats change over time. We do this in the context of the population dynamics of the North American red squirrel, Tamiasciurus hudsonicus, within a forest environment subject to harvesting and regrowth. Harvested patches of forest are initially sinks, then eventually become source habitat again as the forest regrows. At the same time, each harvested patch is gradually recolonized by squirrels from other forest patches. We are interested in the interaction of forest harvesting dynamics with squirrel population dynamics. This depends on the harvesting schedule, and on the choices squirrels make when deciding whether to settle in a mature forest patch or in a recently harvested patch. We find that the time it takes for a second-growth forest patch to be recolonized at the mature forest level is longer than the time required for the habitat quality to be restored to the mature forest level. We also notice that recolonization pressure decreases squirrel populations in neighbouring patches. The connectivity between forest patches and the cutting schedule used also affect the time course of recolonization and steady-state population levels.

Inhibition effects of a negative electret 5-FU patch on the growth of a hypertrophic scar

NASA Astrophysics Data System (ADS)

Wang, YUAN; Lili, XU; Ping, HUANG; Xiaoqiang, AN; Lili, CUI; Jian, JIANG

2018-05-01

In this study, the hypertrophic scar (HS) model in rats was established. 5-fluorouracil (5-FU) patch, ‑1000 V and ‑2000 V polypropylene (PP) electret 5-FU patches were prepared and applied onto the wound. The in vitro permeation experiment was performed using the Franz diffusion cell system to determine the permeation cumulative amount and retention amount of 5-FU through/in scar skin. The inhibition effect of negative electret on growth of HS was studied by hematoxylin-eosin (HE) staining, Masson staining and the immunohistologicall methods. The permeation study indicated that a negative electret could enhance the permeation and retention of 5-FU through and in scar skin respectively. HE staining and Masson staining indicated a better effect for ‑1000 V and ‑2000 V electret 5-FU patches on HS inhibition after 28 d post-wounding compared with 5-FU patch. The immunohistological study showed much more reduced expressions of collegan type I, collegan type III, TGF-β1 and HSP47 in scar tissue after application of negative electret 5-FU patches than those of 5-FU patch. A negative electret 5-FU patch may be advantageous for HS treatment.

Large-scale binding ligand prediction by improved patch-based method Patch-Surfer2.0

PubMed Central

Zhu, Xiaolei; Xiong, Yi; Kihara, Daisuke

2015-01-01

Motivation: Ligand binding is a key aspect of the function of many proteins. Thus, binding ligand prediction provides important insight in understanding the biological function of proteins. Binding ligand prediction is also useful for drug design and examining potential drug side effects. Results: We present a computational method named Patch-Surfer2.0, which predicts binding ligands for a protein pocket. By representing and comparing pockets at the level of small local surface patches that characterize physicochemical properties of the local regions, the method can identify binding pockets of the same ligand even if they do not share globally similar shapes. Properties of local patches are represented by an efficient mathematical representation, 3D Zernike Descriptor. Patch-Surfer2.0 has significant technical improvements over our previous prototype, which includes a new feature that captures approximate patch position with a geodesic distance histogram. Moreover, we constructed a large comprehensive database of ligand binding pockets that will be searched against by a query. The benchmark shows better performance of Patch-Surfer2.0 over existing methods. Availability and implementation: http://kiharalab.org/patchsurfer2.0/ Contact: dkihara@purdue.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25359888

Pattern does not equal process: what does patch occupancy really tell us about metapopulation dynamics?

PubMed

Clinchy, Michael; Haydon, Daniel T; Smith, Andrew T

2002-04-01

Patch occupancy surveys are commonly used to parameterize metapopulation models. If isolation predicts patch occupancy, this is generally attributed to a balance between distance-dependent recolonization and spatially independent extinctions. We investigated whether similar patterns could also be generated by a process of spatially correlated extinctions following a unique colonization event (analogous to nonequilibrium processes in island biogeography). We simulated effects of spatially correlated extinctions on patterns of patch occupancy among pikas (Ochotona princeps) at Bodie, California, using randomly located extinction disks to represent the likely effects of predation. Our simulations produced similar patterns to those cited as evidence of balanced metapopulation dynamics. Simulations using a variety of disk sizes and patch configurations confirmed that our results are potentially applicable to a broad range of species and sites. Analyses of the observed patterns of patch occupancy at Bodie revealed little evidence of rescue effects and strong evidence that most recolonizations are ephemeral in nature. Persistence will be overestimated if static or declining patterns of patch occupancy are mistakenly attributed to dynamically stable metapopulation processes. Consequently, simple patch occupancy surveys should not be considered as substitutes for detailed experimental tests of hypothesized population processes, particularly when conservation concerns are involved.

Preparation of mucoadhesive oral patches containing tetracycline hydrochloride and carvacrol for treatment of local mouth bacterial infections and candidiasis.

PubMed

Obaidat, Rana M; Bader, Ammar; Al-Rajab, Wafa; Abu Sheikha, Ghassan; Obaidat, Aiman A

2011-01-01

The specific aim of this work was to prepare mucoadhesive patches containing tetracycline hydrochloride and carvacrol in an attempt to develop a novel oral drug delivery system for the treatment of mouth infections. The bilayered patches were prepared using ethyl cellulose as a backing layer and carbopol 934 as a matrix mucoadhesive layer. Patches were prepared with different loading amounts of tetracycline hydrochloride and carvacrol. The antimicrobial activity was assessed for the prepared patches using the disc-diffusion method against the yeast Candida albicans and five bacterial strains, including Pseudomonas aeruginosa, Escherichia coli, Bacillus cereus, Staphylococcus aureus, and Bacillus bronchispti. In this work, we highlighted the possibility of occurrence of a synergistic action between carvacrol and tetracycline. The best formulation was selected based on microbiological tests, drug release, ex-vivo mucoadhesive performance, and swelling index. Physical characteristics of the selected formulations were determined. These included pH, patch thickness, weight uniformity, content uniformity, folding endurance, and patch stability.

Patch-clamp amplifiers on a chip

PubMed Central

Weerakoon, Pujitha; Culurciello, Eugenio; Yang, Youshan; Santos-Sacchi, Joseph; Kindlmann, Peter J.; Sigworth, Fred J.

2010-01-01

We present the first, fully-integrated, two-channel implementation of a patch-clamp measurement system. With this “PatchChip” two simultaneous whole-cell recordings can be obtained with rms noise of 8 pA in a 10 kHz bandwidth. The capacitance and series-resistance of the electrode can be compensated up to 10 pF and 100 MΩ respectively under computer control. Recordings of hERG and Nav 1.7 currents demonstrate the system's capabilities, which are on par with large, commercial patch-clamp instrumentation. By reducing patch-clamp amplifiers to a millimeter size micro-chip, this work paves the way to the realization of massively-parallel, high-throughput patch-clamp systems for drug screening and ion-channel research. The PatchChip is implemented in a 0.5 μm silicon-on-sapphire process; its size is 3 × 3 mm2 and the power consumption is 5 mW per channel with a 3.3 V power supply. PMID:20637803

Hydrologic connection between ponds positively affects macrophyte alpha and gamma diversity but negatively affects beta diversity.

PubMed

Akasaka, Munemitsu; Takamura, Noriko

2012-05-01

Connections between habitat patches can positively influence the number of species in respective patches, providing a basis for preferentially conserving interconnected patches. However, from a regional perspective, it is not known whether conserving multiple sets of interconnected habitat patches would include more species (i.e., show higher gamma diversity) than conserving multiple, unconnected, solitary patches. We studied aquatic macrophytes in 15 sets of unidirectionally interconnected ponds and 19 unconnected ponds and also tested whether alpha and beta diversity, expressed as the number of species and dissimilarity in species composition, respectively, differed between connected and unconnected ponds. We found that gamma diversity was higher in connected ponds than in unconnected ponds, even after controlling for surface area. This resulted from a higher alpha diversity in connected ponds, despite lower beta diversity. These results suggest that connections between habitat patches positively influence diversity at both local and regional scales. When the total surface area available for conservation is limited, interconnected habitat patches should be preferentially conserved.

Resonant frequencies of irregularly shaped microstrip antennas using method of moments

NASA Technical Reports Server (NTRS)

Deshpande, Manohar D.; Shively, David G.; Cockrell, C. R.

1993-01-01

This paper describes an application of the method of moments to determine resonant frequencies of irregularly shaped microstrip patches embedded in a grounded dielectric slab. For analysis, the microstrip patch is assumed to be excited by a linearly polarized plane wave that is normal to the patch. The surface-current density that is induced on the patch because of the incident field is expressed in terms of subdomain functions by dividing the patch into identical rectangular subdomains. The amplitudes of the subdomain functions, as a function of frequency, are determined using the electric-field integral equation (EFIE) approach in conjunction with the method of moments. The resonant frequencies of the patch are then obtained by selecting the frequency at which the amplitude of the surface-current density is real. The resonant frequencies of the equilateral triangular and other nonrectangular patches are computed using the present technique, and these frequencies are compared with measurements and other independent calculations.

Facilitated giga-seal formation with a just originated glass surface.

PubMed

Böhle, T; Benndorf, K

1994-07-01

A simple technique of tip preparation in patch pipettes is described, which facilitates giga-seal formation. The pipettes were fabricated from thick-walled borosilicate glass tubing (external diameter 2.0 mm, internal diameter 0.5 mm) and the tips could be repeatedly broken in the bath. The pipette resistance correspondingly fell in steps of 3-20 M omega from about 80 M omega to about 2 M omega (double concentrated Tyrode). Scanning electron microscopy showed that the tip obtained after breaking was fairly plain. These broken tips were especially appropriate for patch-clamping. In cardiac myocytes in 11 out of 26 patches with Na+ channel activity, giga-seals developed spontaneously, i.e. without suction. In these patches the amplitude of the mean current with depolarizing pulses to -40 mV was significantly higher in comparison with patches formed under negative pressure. It is concluded that spontaneously sealed patches are most likely of planar configuration and the Na+ channel activity exceeds that in suction-induced patches.

Generalized peritonitis requiring re-operation after leakage of omental patch repair of perforated peptic ulcer.

PubMed

Maghsoudi, Hemmat; Ghaffari, Alireza

2011-01-01

Peptic ulcer perforations are a common emergency, but available literature is silent on the exact definition, incidence, management, and complications of peritonitis due to omental patch leakage. Retrospective data were collected on 422 patients who underwent omental patch repair of perforated peptic ulcer between March 20, 1999 and March 20, 2006. The definitive diagnosis of perforated peptic ulcer and omental patch leakage was obtained at surgery. Seventeen (4%) patients experienced generalized peritonitis due to omental patch leakage. Mean age was 60.6 years. Mortality rate was 29.4%, and the mean hospital stay was 23.6 days. Delay in surgical approach, shock on admission, and age were all significantly associated with increased mortality. Peritonitis due to omental patch leakage can result in significant morbidity and mortality. The most common causes of omental patch leakage and operative procedures were unknown and reinsertion of omentum, respectively. Factors such as shock on admission or delayed surgery, have significantly contributed to fatal outcomes and need careful attention.

Prediction of Fatigue Crack Growth of Repaired Al-alloy Structures with Double Sides

NASA Astrophysics Data System (ADS)

Benachour, M.; Benachour, N.; Benguediab, M.; Seriari, F. Z.

During navigation, aircrafts are subject to fatigue damage. In order to rehabilitate damaged structures some techniques are often used to resolve this problem. Efficient repair technique, called composite patch repair, was used to reinforce the damaged structures and stop cracks. In this paper, effect of composite patch repair (Boron/Epoxy) on fatigue crack growth (FCG) was investigated on 2219 T62 Al-alloy. Effects of double patch repair in single notch tensile specimen (SENT) on FCG were studied and compared to single patch repair. Results show beneficial effect of patch repair on fatigue life and FCGR in comparison with the un-patched specimen. In addition, effect of mean stress characterized by stress ratio was highlighted. Fatigue behavior of investigated Al-alloy was compared.

Is there a risk of active sensitization to PPD by patch testing the general population?

PubMed

Thyssen, Jacob Pontoppidan; Menné, Torkil; Nielsen, Niels Henrik; Linneberg, Allan

2007-08-01

Para-phenylenediamine (PPD), a constituent of permanent hair dyes, may cause contact allergy in exposed individuals. It has previously been questioned whether a patch testing with PPD in population-based epidemiological studies is entirely safe. The Glostrup allergy studies patch tested the same cohort twice. In 1990, 567 persons were patch-tested and only one person had a (+) positive reaction to PPD. In 1998, 540 persons were re-invited to a new patch test and 365 (participation rate 68%) were re-tested. There were no positive reactions to PPD. These studies indicate that patch testing with PPD in individuals with no previous positive reactions to PPD or with only one previous positive reaction does not cause active sensitization and can be performed with minimal risk.

The effect of a nicotine patch on cigarette craving over the course of the day: results from two randomized clinical trials.

PubMed

Shiffman, Saul; Ferguson, Stuart G

2008-10-01

The objective of this analysis was to assess the efficacy of a 21 mg/24-h nicotine patch for the reduction of craving throughout the waking day, compared both to placebo, and to a 15 mg/16-h patch differing pharmacokinetic profile over the day. The primary end-point was craving during the evening hours, because previous research suggested that smoking relapse was particularly likely at that time. Data were drawn from two similar randomized clinical trials among nicotine-dependent smokers who were quitting smoking: Study 1 compared the 21 mg/24-h patch to a placebo patch, while Study 2 compared the 21 mg/24-h patch to a 15 mg/16-h nicotine patch. In both studies, subjects (Study 1: n = 102; Study 2: n = 244) were prompted by an electronic diary to rate their craving multiple times per day during a 1 week baseline period, and for up to 2 weeks after quitting. For analysis, the day was divided into five blocks: morning (up to 10:59 a.m.), mid-day (11:00 a.m.-1:59 p.m.), afternoon (2:00 p.m.-4:59 p.m.), evening (5:00 p.m.-8:59 p.m.), and late night (9:00 p.m. onwards). The individual craving ratings were divided into three intervals based on time since quitting: Days 1-3, 4-7, and 8-14. The 21 mg/24-h nicotine patch resulted in significantly lower craving during all post-quit intervals, at each time of day, both compared to placebo (Study 1), and compared to the 15 mg/16-h nicotine patch (Study 2). Study 2 saw a significant treatment by interval interaction: in later time intervals, the difference in craving experience between 24- and 16-h patch conditions shrunk--while remaining significantly different--as overall levels of craving experienced by subjects in the two groups dropped. Adverse events reported in both studies tended to be mild and transient, consistent with the well characterized adverse event profile of nicotine patches. Study 1 demonstrated that a 21 mg/24-h patch was effective in reducing craving throughout the day, including the evening period when relapse risk is heightened. A further study comparing the 21 mg/24-h patch to a 15 mg/16-h nicotine patch found that craving was significantly lower at all times of day for smokers using the 21 mg/24-h patch. The studies were limited in that craving was only monitored for the first 2 weeks of quitting (when craving is most prominent), and cannot elucidate the impact of patch use on craving outside of this time. Also, there was substantial attrition of the sample over time, partly due to relapse in all conditions.

Mechanical Development of a Very Non-Standard Patch Array Antenna for Extreme Environments

NASA Technical Reports Server (NTRS)

Hughes, Richard; Chamberlain, Neil; Jakoboski, Julie; Petkov, Mihail

2012-01-01

This paper describes the mechanical development of patch antenna arrays for the Juno mission. The patch arrays are part of a six-frequency microwave radiometer instrument that will be used to measure thermal emissions from Jupiter. The very harsh environmental conditions in Jupiter orbit, as well as a demanding launch environment, resulted in a design that departs radically from conventional printed circuit patch antennas. The paper discusses the development and qualification of the Juno patch array antennas, with emphasis on the materials approach that was devised to mitigate the effects of electron charging in Jupiter orbit.

Cell-Detection Technique for Automated Patch Clamping

NASA Technical Reports Server (NTRS)

McDowell, Mark; Gray, Elizabeth

2008-01-01

A unique and customizable machinevision and image-data-processing technique has been developed for use in automated identification of cells that are optimal for patch clamping. [Patch clamping (in which patch electrodes are pressed against cell membranes) is an electrophysiological technique widely applied for the study of ion channels, and of membrane proteins that regulate the flow of ions across the membranes. Patch clamping is used in many biological research fields such as neurobiology, pharmacology, and molecular biology.] While there exist several hardware techniques for automated patch clamping of cells, very few of those techniques incorporate machine vision for locating cells that are ideal subjects for patch clamping. In contrast, the present technique is embodied in a machine-vision algorithm that, in practical application, enables the user to identify good and bad cells for patch clamping in an image captured by a charge-coupled-device (CCD) camera attached to a microscope, within a processing time of one second. Hence, the present technique can save time, thereby increasing efficiency and reducing cost. The present technique involves the utilization of cell-feature metrics to accurately make decisions on the degree to which individual cells are "good" or "bad" candidates for patch clamping. These metrics include position coordinates (x,y) in the image plane, major-axis length, minor-axis length, area, elongation, roundness, smoothness, angle of orientation, and degree of inclusion in the field of view. The present technique does not require any special hardware beyond commercially available, off-the-shelf patch-clamping hardware: A standard patchclamping microscope system with an attached CCD camera, a personal computer with an imagedata- processing board, and some experience in utilizing imagedata- processing software are all that are needed. A cell image is first captured by the microscope CCD camera and image-data-processing board, then the image data are analyzed by software that implements the present machine-vision technique. This analysis results in the identification of cells that are "good" candidates for patch clamping (see figure). Once a "good" cell is identified, a patch clamp can be effected by an automated patchclamping apparatus or by a human operator. This technique has been shown to enable reliable identification of "good" and "bad" candidate cells for patch clamping. The ultimate goal in further development of this technique is to combine artificial-intelligence processing with instrumentation and controls in order to produce a complete "turnkey" automated patch-clamping system capable of accurately and reliably patch clamping cells with a minimum intervention by a human operator. Moreover, this technique can be adapted to virtually any cellular-analysis procedure that includes repetitive operation of microscope hardware by a human.

Analysis and modelling of recurrent solar flares observed with Hinode/EIS on March 9, 2012

NASA Astrophysics Data System (ADS)

Polito, V.; Del Zanna, G.; Valori, G.; Pariat, E.; Mason, H. E.; Dudík, J.; Janvier, M.

2017-05-01

Three homologous C-class flares and one last M-class flare were observed by both the Solar Dynamics Observatory (SDO) and the Hinode EUV Imaging Spectrometer (EIS) in the AR 11429 on March 9, 2012. All the recurrent flares occurred within a short interval of time (less than 4 h), showed very similar plasma morphology and were all confined, until the last one when a large-scale eruption occurred. The C-class flares are characterized by the appearance, at approximatively the same locations, of two bright and compact footpoint sources of ≈3-10 MK evaporating plasma, and a semi-circular ribbon. During all the flares, the continuous brightening of a spine-like hot plasma (≈10 MK) structure is also observed. Spectroscopic observations with Hinode/EIS are used to measure and compare the blueshift velocities in the Fe xxiii emission line and the electron number density at the flare footpoints for each flare. Similar velocities, of the order of 150-200 km s-1, are observed during the C2.0 and C4.7 confined flares, in agreement with the values reported by other authors in the study of the last M1.8 class flare. On the other hand, lower electron number densities and temperatures tend to be observed in flares with lower peak soft X-ray flux. In order to investigate the homologous nature of the flares, we performed a non-linear force-free field (NLFFF) extrapolation of the 3D magnetic field configuration in the corona. The NLFFF extrapolation and the Quasi-Separatrix Layers (QSLs) provide the magnetic field context which explains the location of the kernels, spine-like hot plasma and semi-circular brightenings observed in the (non-eruptive) flares. Given the absence of a coronal null point, we argue that the homologous flares were all generated by the continuous recurrence of bald patch reconnection. The movie associated to Fig. 2 is available at http://www.aanda.org

UV-cured adhesives for carbon fiber composite applications

NASA Astrophysics Data System (ADS)

Lu, Hsiao-Chun

Carbon fiber composite materials are increasingly used in automobile, marine, and aerospace industries due to their unique properties, including high strength, high stiffness and low weight. However, due to their brittle characteristic, these structures are prone to physical damage, such as a bird strike or impact damage. Once the structure is damaged, it is important to have fast and reliable temporary repair until the permanent repair or replacement can take place. In this dissertation, UV-based adhesives were used to provide a bonding strength for temporary repair. Adhesively bonded patch repair is an efficient and effective method for temporary repair. In this study, precured patches (hard patches) and dry fabric patches with laminating resins (soft patches) were performed. UV-based epoxy adhesives were applied to both patch repair systems. For precured patch repair, the bonding strengths were investigated under different surface treatments for bonding area and different adhesives thicknesses. The shear stresses of different UV exposure times and curing times were tested. Besides, the large patch repair was investigated as well. For soft patch repair, the hand wet lay-up was applied due to high viscosity of UV resins. A modified single lap shear testing (ASTM D5868) was applied to determine the shear stress. The large patches used fiber glass instead of carbon fiber to prove the possibility of repair with UV epoxy resin by hand wet lay-up process. The hand lay-up procedure was applied and assisted by vacuum pressure to eliminate the air bubbles and consolidate the patches. To enhance the bonding strength and effective soft patch repair, vacuum assisted resin transferring molding (VaRTM) is the better option. However, only low viscosity resins can be operated by VaRTM. Hence, new UV-based adhesives were formulated. The new UV-based adhesives included photoinitiator (PI), epoxy and different solvents. Solvents were used to compound the photoinitiator into epoxy monomer. Acetone, tetrahydrofuran (THF) and chloroform were used as well as their anhydrous solvents. The UV exposure times and curing times of new UV-based resins were tested. FT-IR, DSC and DMA were used to investigate structure, glass transition temperatures(Tg) and properties of polymer. In summary, the UV-based adhesive was applied to adhesively bonded hard patch and soft patch repair. In addition, new UV-based resins were formulated for the VaRTM process. The in-field repair can be effective and efficient by using UV adhesives.

An experimental test of whether habitat corridors affect pollen transfer.

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

Townsend, Patricia A.; Levey, Douglas J.

Abstract. Negative effects of habitat fragmentation are thought to be diminished when habitat patches are joined by a corridor. A key assumption is that corridors facilitate exchange rates of organisms between otherwise isolated patches. If the organisms are pollinators, corridors may be important for maintaining genetically viable populations of the plants that they pollinate. We tested the hypothesis that corridors increase the movement of insect pollinators into patches of habitat and thereby increase pollen transfer for two species of plants, one pollinated by butterflies (Lantana camara) and the other by bees and wasps (Rudbeckia hirta). We worked in an experimentalmore » landscape consisting of 40 greater than or equal to 1-ha patches of early-successional habitat in a matrix of forest. Within each of eight experimental units, two patches were connected by a corridor (150 X 25 m), and three were not. Patch shape varied to control for the area added by the presence of a corridor. Differences in patch shape also allowed us to test alternative hypotheses of how corridors might function. The Traditional Corridor Hypothesis posits that corridors increase immigration and emigration by functioning as movement conduits between patches. The Drift Fence Hypothesis posits that corridors function by ‘‘capturing’’ organisms dispersing through the matrix, redirecting them into associated habitat patches. Using fluorescent powder to track pollen, we found that pollen transfer by butterflies between patches connected by a corridor was significantly higher than between unconnected patches (all values mean plus or minus 1 SE: 59% plus or minus 9.2% vs. 25% plus or minus 5.2% of flowers receiving pollen). Likewise, pollen transfer by bees and wasps was significantly higher between connected patches than between unconnected patches (30% plus or minus 4.2% vs. 14.5% plus or minus 2.2%). These results support the Traditional Corridor Hypothesis. There was little support, however, for the Drift Fence Hypothesis. To generalize our results to a larger scale, we measured the probability of pollen transfer by butterflies as a function of distance along a 2000 X 75 m corridor. Pollen transfer probability exponentially declined with respect to distance and successfully predicted pollen transfer probability on the scale of our previous experiment. These results suggest that corridors facilitate pollen transfer in fragmented landscapes.« less

Coupled Human-Environment Dynamics of Forest Pest Spread and Control in a Multi-Patch, Stochastic Setting

PubMed Central

Ali, Qasim; Bauch, Chris T.; Anand, Madhur

2015-01-01

Background The transportation of camp firewood infested by non-native forest pests such as Asian long-horned beetle (ALB) and emerald ash borer (EAB) has severe impacts on North American forests. Once invasive forest pests are established, it can be difficult to eradicate them. Hence, preventing the long-distance transport of firewood by individuals is crucial. Methods Here we develop a stochastic simulation model that captures the interaction between forest pest infestations and human decisions regarding firewood transportation. The population of trees is distributed across 10 patches (parks) comprising a “low volume” partition of 5 patches that experience a low volume of park visitors, and a “high volume” partition of 5 patches experiencing a high visitor volume. The infestation spreads within a patch—and also between patches—according to the probability of between-patch firewood transportation. Individuals decide to transport firewood or buy it locally based on the costs of locally purchased versus transported firewood, social norms, social learning, and level of concern for observed infestations. Results We find that the average time until a patch becomes infested depends nonlinearly on many model parameters. In particular, modest increases in the tree removal rate, modest increases in public concern for infestation, and modest decreases in the cost of locally purchased firewood, relative to baseline (current) values, cause very large increases in the average time until a patch becomes infested due to firewood transport from other patches, thereby better preventing long-distance spread. Patches that experience lower visitor volumes benefit more from firewood movement restrictions than patches that experience higher visitor volumes. Also, cross–patch infestations not only seed new infestations, they can also worsen existing infestations to a surprising extent: long-term infestations are more intense in the high volume patches than the low volume patches, even when infestation is already endemic everywhere. Conclusions The success of efforts to prevent long-distance spread of forest pests may depend sensitively on the interaction between outbreak dynamics and human social processes, with similar levels of effort producing very different outcomes depending on where the coupled human and natural system exists in parameter space. Further development of such modeling approaches through better empirical validation should yield more precise recommendations for ways to optimally prevent the long-distance spread of invasive forest pests. PMID:26430902

Use of nicotine patches in breast-feeding mothers: transfer of nicotine and cotinine into human milk.

PubMed

Ilett, Kenneth F; Hale, Thomas W; Page-Sharp, Madhu; Kristensen, Judith H; Kohan, Rolland; Hackett, L Peter

2003-12-01

Our objective was to assess the extent of exposure to nicotine and cotinine in breast-fed infants during maternal smoking and later during maternal use of the nicotine transdermal patch to achieve smoking cessation. Fifteen lactating women (mean age, 32 years; mean weight, 72 kg) who were smokers (mean of 17 cigarettes per day) participated in a trial of the nicotine patch to assist in smoking cessation. Serial milk samples were collected from the women over sequential 24-hour periods when they were smoking and when they were stabilized on the 21-mg/d, 14-mg/d, and 7-mg/d nicotine patches. Nicotine and cotinine in milk were quantified by HPLC, and infant dose was calculated. Plasma concentrations of nicotine in the breast-fed infants were assessed, and the infants were also clinically assessed. Nicotine and cotinine concentrations in milk were not significantly different between smoking (mean of 17 cigarettes per day) and the 21-mg/d patch, but concentrations were significantly lower (P <.05) when patients were using the 14-mg/d and 7-mg/d patches than when smoking. There was also a downward trend in absolute infant dose (nicotine equivalents) from smoking or the 21-mg patch through to the 14-mg and 7-mg patches (P <.05 at both 14-mg and 7-mg doses, compared with smoking). Milk intake (shown as median and 25th to 75th percentile) by the breast-fed infants was similar while their mothers were smoking (585 mL/d [507-755 mL/d]) and subsequently when their mothers were using the 21-mg (717 mL/d [504-776 mL/d]), 14-mg (731 mL/d [535-864 mL/d]), and 7-mg (619 mL/d [520-706 mL/d]) patches (chi(2) = 3.19, P =.364). We conclude that the absolute infant dose of nicotine and its metabolite cotinine decreases by about 70% from when subjects were smoking or using the 21-mg patch to when they were using the 7-mg patch. In addition, use of the nicotine patch had no significant influence on the milk intake by the breast-fed infant. Undertaking maternal smoking cessation with the nicotine patch is, therefore, a safer option than continued smoking.

Attitudes about Advances in Sweat Patch Testing in Drug Courts: Insights from a Case Study in Southern California

ERIC Educational Resources Information Center

Polzer, Katherine

2010-01-01

Drug courts are reinventing the drug testing framework by experimenting with new methods, including use of the sweat patch. The sweat patch is a band-aid like strip used to monitor drug court participants. The validity and reliability of the sweat patch as an effective testing method was examined, as well as the effectiveness, meaning how likely…

Use of the pulsed infrared diode laser (904 nm) in the treatment of alopecia areata.

PubMed

Waiz, Makram; Saleh, Anmar Z; Hayani, Raafa; Jubory, Samar O

2006-04-01

Alopecia areata is a rapid and complete loss of hair in one or several patches, usually on the scalp, affecting both males and females equally. It is thought to be an autoimmune disease which is treated with different modalities with variable success. Laser treatment of different wavelengths has been used in the management of this problem. To study the effect of the pulsed infrared diode laser (904 nm) in the treatment of alopecia areata.Methods. Sixteen patients with 34 resistant patches that had not responded to different treatment modalities for alopecia areata were enrolled in this study. In patients with multiple patches, one patch was left as a control for comparison. Patients were treated on a four-session basis, once a week, with a pulsed diode laser (904 nm) at a pulse rate of 40/s. A photograph was taken of each patient before and after treatment. The treated patients were 11 males (68.75%) and five females (31.25%). Their ages ranged between 4 and 50 years with a mean of 26.6+/-SD of +/-13.8, and the durations of their disease were between 12 months and 6 years with a mean of 13.43+/-SD of +/-18.34. Regrowth of hair was observed in 32 patches (94%), while only two patches (6%) failed to show any response. No regrowth of hair was observed in the control patches. The regrowth of hair appeared as terminal hair with its original color in 29 patches (90.6%), while three patches (9.4%) appeared as a white villous hair. In patients who showed response, the response was detected as early as 1 week after the first session in 24 patches (75%), while eight patients (25%) started to show response from the second session. The pulsed infrared diode laser is an effective mode of therapy with a high success rate for resistant patches of alopecia areata.

Selective versus routine patch metal allergy testing to select bar material for the Nuss procedure in 932 patients over 10years.

PubMed

Obermeyer, Robert J; Gaffar, Sheema; Kelly, Robert E; Kuhn, M Ann; Frantz, Frazier W; McGuire, Margaret M; Paulson, James F; Kelly, Cynthia S

2018-02-01

The aim of the study was to determine the role of patch metal allergy testing to select bar material for the Nuss procedure. An IRB-approved (11-04-WC-0098) single institution retrospective, cohort study comparing selective versus routine patch metal allergy testing to select stainless steel or titanium bars for Nuss repair was performed. In Cohort A (9/2004-1/2011), selective patch testing was performed based on clinical risk factors. In Cohort B (2/2011-9/2014), all patients were patch tested. The cohorts were compared for incidence of bar allergy and resultant premature bar loss. Risk factors for stainless steel allergy or positive patch test were evaluated. Cohort A had 628 patients with 63 (10.0%) selected for patch testing, while all 304 patients in Cohort B were tested. Over 10years, 15 (1.8%) of the 842 stainless steel Nuss repairs resulted in a bar allergy, and 5 had a negative preoperative patch test. The incidence of stainless steel bar allergy (1.8% vs 1.7%, p=0.57) and resultant bar loss (0.5% vs 1.3%, p=0.23) was not statistically different between cohorts. An allergic reaction to a stainless steel bar or a positive patch test was more common in females (OR=2.3, p<0.001) and patients with a personal (OR=24.8, p<0.001) or family history (OR=3.1, p<0.001) of metal sensitivity. Stainless steel bar allergies occur at a low incidence with either routine or selective patch metal allergy testing. If selective testing is performed, it is advisable in females and patients with a personal or family history of metal sensitivity. A negative preoperative patch metal allergy test does not preclude the possibility of a postoperative stainless steel bar allergy. Level III Treatment Study and Study of Diagnostic Test. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of rapid urban sprawl on urban forest carbon stocks: integrating remotely sensed, GIS and forest inventory data.

PubMed

Ren, Yin; Yan, Jing; Wei, Xiaohua; Wang, Yajun; Yang, Yusheng; Hua, Lizhong; Xiong, Yongzhu; Niu, Xiang; Song, Xiaodong

2012-12-30

Research on the effects of urban sprawl on carbon stocks within urban forests can help support policy for sustainable urban design. This is particularly important given climate change and environmental deterioration as a result of rapid urbanization. The purpose of this study was to quantify the effects of urban sprawl on dynamics of forest carbon stock and density in Xiamen, a typical city experiencing rapid urbanization in China. Forest resource inventory data collected from 32,898 patches in 4 years (1972, 1988, 1996 and 2006), together with remotely sensed data (from 1988, 1996 and 2006), were used to investigate vegetation carbon densities and stocks in Xiamen, China. We classified the forests into four groups: (1) forest patches connected to construction land; (2) forest patches connected to farmland; (3) forest patches connected to both construction land and farmland and (4) close forest patches. Carbon stocks and densities of four different types of forest patches during different urbanization periods in three zones (urban core, suburb and exurb) were compared to assess the impact of human disturbance on forest carbon. In the urban core, the carbon stock and carbon density in all four forest patch types declined over the study period. In the suburbs, different urbanization processes influenced forest carbon density and carbon stock in all four forest patch types. Urban sprawl negatively affected the surrounding forests. In the exurbs, the carbon stock and carbon density in all four forest patch types tended to increase over the study period. The results revealed that human disturbance played the dominant role in influencing the carbon stock and density of forest patches close to the locations of human activities. In forest patches far away from the locations of human activities, natural forest regrowth was the dominant factor affecting carbon stock and density. Copyright © 2012 Elsevier Ltd. All rights reserved.

Absorption, accumulation and biological effects of depleted uranium in Peyer's patches of rats.

PubMed

Dublineau, I; Grison, S; Grandcolas, L; Baudelin, C; Tessier, C; Suhard, D; Frelon, S; Cossonnet, C; Claraz, M; Ritt, J; Paquet, P; Voisin, P; Gourmelon, P

2006-10-29

The digestive tract is the entry route for radionuclides following the ingestion of contaminated food and/or water wells. It was recently characterized that the small intestine was the main area of uranium absorption throughout the gastrointestinal tract. This study was designed to determine the role played by the Peyer's patches in the intestinal absorption of uranium, as well as the possible accumulation of this radionuclide in lymphoid follicles and the toxicological or pathological consequences on the Peyer's patch function subsequent to the passage and/or accumulation of uranium. Results of experiments performed in Ussing chambers indicate that the apparent permeability to uranium in the intestine was higher (10-fold) in the mucosa than in Peyer's patches ((6.21+/-1.21 to 0.55+/-0.35)x10(-6)cm/s, respectively), demonstrating that the small intestinal epithelium was the preferential pathway for the transmucosal passage of uranium. A quantitative analysis of uranium by ICP-MS following chronic contamination with depleted uranium during 3 or 9 months showed a preferential accumulation of uranium in Peyer's patches (1355% and 1266%, respectively, at 3 and 9 months) as compared with epithelium (890% and 747%, respectively, at 3 and 9 months). Uranium was also detected in the mesenteric lymph nodes ( approximately 5-fold after contamination with DU). The biological effects of this accumulation of depleted uranium after chronic contamination were investigated in Peyer's patches. There was no induction of the apoptosis pathway after chronic DU contamination in Peyer's patches. The results indicate no change in the cytokine expression (Il-10, TGF-beta, IFN-gamma, TNF-alpha, MCP-1) in Peyer's patches and in mesenteric lymph nodes, and no modification in the uptake of yeast cells by Peyer's patches. In conclusion, this study shows that the Peyer's patches were a site of retention for uranium following the chronic ingestion of this radionuclide, without any biological consequences of such accumulation on Peyer's patch functions.

Mesoscale Magnetosphere-Ionosphere Coupling along Open Magnetic Field Lines Associated with Airglow Patches: Field-aligned Currents and Precipitation

NASA Astrophysics Data System (ADS)

Zou, Y.; Nishimura, Y.; Lyons, L. R.; Shiokawa, K.; Burchill, J. K.; Knudsen, D. J.; Buchert, S. C.; Chen, S.; Nicolls, M. J.; Ruohoniemi, J. M.; McWilliams, K. A.; Nishitani, N.

2016-12-01

Although airglow patches are traditionally regarded as high-density plasma unrelated to local field-aligned currents (FACs) and precipitation, past observations were limited to storm-time conditions. Recent non-storm time observations show patches to be associated with azimuthally narrow ionospheric fast flow channels that substantially contribute to plasma transportation across the polar cap and connect dayside and nightside explosive disturbances. We examine whether non-storm time patches are related also to localized polar cap FACs and precipitation using Swarm- and FAST-imager-radar conjunctions. In Swarm data, we commonly (66%) identify substantial magnetic perturbations indicating FAC enhancements around patches. These FACs have substantial densities (0.1-0.2 μA/m-2) and can be approximated as infinite current sheets (typically 75 km wide) orientated roughly parallel to patches. They usually exhibit a Region-1 sense, i.e. a downward FAC lying eastward of an upward FAC, and can close through Pedersen currents in the ionosphere, implying that the locally enhanced dawn-dusk electric field across the patch is imposed by processes in the magnetosphere. In FAST data, we identify localized precipitation that is enhanced within patches in comparison to weak polar rain outside patches. The precipitation consists of structured or diffuse soft electron fluxes. While the latter resembles polar rain only with higher fluxes, the former consists of discrete fluxes enhanced by 1-2 orders of magnitude from several to several hundred eV. Although the precipitation is not a major contributor to patch ionization, it implies that newly reconnected flux tubes that retain electrons of magnetosheath origin can rapidly traverse the polar cap from the dayside. Therefore non-storm time patches should be regarded as part of a localized magnetosphere-ionosphere coupling system along open magnetic field lines, and their transpolar evolution as a reflection of reconnected flux tubes traveling from the dayside to nightside magnetosphere.

The effect of altitude, patch size and disturbance on species richness and density of lianas in montane forest patches

NASA Astrophysics Data System (ADS)

Mohandass, Dharmalingam; Campbell, Mason J.; Hughes, Alice C.; Mammides, Christos; Davidar, Priya

2017-08-01

The species richness and density of lianas (woody vines) in tropical forests is determined by various abiotic and biotic factors. Factors such as altitude, forest patch size and the degree of forest disturbance are known to exert strong influences on liana species richness and density. We investigated how liana species richness and density were concurrently influenced by altitude (1700-2360 m), forest patch size, forest patch location (edge or interior) and disturbance intensity in the tropical montane evergreen forests, of the Nilgiri and Palni hills, Western Ghats, southern India. All woody lianas (≥1 cm dbh) were enumerated in plots of 30 × 30 m in small, medium and large forest patches, which were located along an altitudinal gradient ranging from 1700 to 2360 m. A total of 1980 individual lianas were recorded, belonging to 45 species, 32 genera and 21 families, from a total sampling area of 13.86 ha (across 154 plots). Liana species richness and density decreased significantly with increasing altitude and increased with increasing forest patch size. Within forest patches, the proportion of forest edge or interior habitat influenced liana distribution and succession especially when compared across the patch size categories. Liana species richness and density also varied along the altitudinal gradient when examined using eco-physiological guilds (i.e. shade tolerance, dispersal mode and climbing mechanism). The species richness and density of lianas within these ecological guilds responded negatively to increasing altitude and positively to increasing patch size and additionally displayed differing sensitivities to forest disturbance. Importantly, the degree of forest disturbance significantly altered the relationship between liana species richness and density to increasing altitude and patches size, and as such is likely the primary influence on liana response to montane forest succession. Our findings suggest that managing forest disturbance in the examined montane forests would assist in conserving local liana diversity across the examined altitudinal range.

Estradiol Transdermal Patch

MedlinePlus

Most brands of estradiol transdermal patches are used to treat hot flushes (hot flashes; sudden strong feelings of heat ... different medication that does not contain estrogen. Most brands of estradiol transdermal patches are also sometimes used ...

Ultra low concentration deltamethrin loaded patch development and evaluation of its repellency against dengue vector Aedes (S) albopictus

PubMed Central

2013-01-01

Background Mosquito repellents and emanators confer protection against mosquito bites through spatial action of emanated vapours which are released into the adjoining environment. Synthetic insecticides released into the environment in ultra low volume vapour phase deter the mosquitoes from biting humans in a protected space. Methods Formulation patches were prepared using the solvent evaporation method over a backing membrane and using Dibutylphthalate (DBT) as a plasticizer. The effect of formulation variables on the deltamethrin release from the patch matrices were studied under accelerated conditions, whereas, HPLC was used for quantitative estimation of deltamethrin. The prepared patch formulations were subjected to physicochemical studies, such as, deltamethrin content, thickness, weight variation, percent moisture content, moisture uptake, surface area and surface pH determination. Deltamethrin-polymer interaction and compatibility was ascertained using DSC and FT-IR, while surface morphology and deltamethrin distribution in the patch were studied using SEM technique. Repellent activity of the patch formulations was evaluated against Ae. albopictus mosquitoes. Results Blends of polymeric combinations of polyvinylpyrrolidone (PVP) and ethyl-cellulose (EC) with admixture of deltamethrin provided prolonged repellent activity against Ae. albopictus mosquitoes. Physicochemical characterisation indicated the suitability of deltamethrin patch formulation with the polymeric combinations of PVP and EC. Patches were very effective against laboratory reared Ae. albopictus mosquitoes. No significant difference was observed between the performance of test patches and commercially available repellent cream Mosqshield®. Conclusion Deltamethrin loaded patches provided effective repellency against Ae. albopictus mosquitoes. The study emphasised that deltamethrin released to the environment in low concentration could be an excellent spatial repellent against hematophagous mosquitoes. PMID:24289656

Estimated home ranges can misrepresent habitat relationships on patchy landscapes

USGS Publications Warehouse

Mitchell, M.S.; Powell, R.A.

2008-01-01

Home ranges of animals are generally structured by the selective use of resource-bearing patches that comprise habitat. Based on this concept, home ranges of animals estimated from location data are commonly used to infer habitat relationships. Because home ranges estimated from animal locations are largely continuous in space, the resource-bearing patches selected by an animal from a fragmented distribution of patches would be difficult to discern; unselected patches included in the home range estimate would bias an understanding of important habitat relationships. To evaluate potential for this bias, we generated simulated home ranges based on optimal selection of resource-bearing patches across a series of simulated resource distributions that varied in the spatial continuity of resources. For simulated home ranges where selected patches were spatially disjunct, we included interstitial, unselected cells most likely to be traveled by an animal moving among selected patches. We compared characteristics of the simulated home ranges with and without interstitial patches to evaluate how insights derived from field estimates can differ from actual characteristics of home ranges, depending on patchiness of landscapes. Our results showed that contiguous home range estimates could lead to misleading insights on the quality, size, resource content, and efficiency of home ranges, proportional to the spatial discontinuity of resource-bearing patches. We conclude the potential bias of including unselected, largely irrelevant patches in the field estimates of home ranges of animals can be high, particularly for home range estimators that assume uniform use of space within home range boundaries. Thus, inferences about the habitat relationships that ultimately define an animal's home range can be misleading where animals occupy landscapes with patchily distributed resources.

Photo-patch and patch tests in patients with dermatitis over the photo-exposed areas: A study of 101 cases from a tertiary care centre in India.

PubMed

Sharma, Vinod Kumar; Bhari, Neetu; Wadhwani, Ashok Roopchand; Bhatia, Riti

2018-02-01

Many patients with dermatitis over photo-exposed body areas are positive to many contact allergens and have a pre-existing allergic contact dermatitis. This study included patients who presented to a tertiary centre in India with dermatitis on photo-exposed body areas suspected of chronic actinic dermatitis. Their detailed histories were recorded and cutaneous and systemic examinations were performed. Patch testing was done in all the patients and photo-patch testing was carried out in 86 patients. Altogether 101 patients were included (69 males, 32 females). The most common presentation was lichenified hyperpigmented plaques on the photo-exposed sites. Photosensitivity was recorded in 64 (63%) patients and summer exacerbation in 52 (52%). Exposure to the Parthenium hysterophorus weed was recorded in 70 (69%) patients, 27 (26.7%) had a history of hair dye application and 20 (20%) had a history of atopy. Photo-patch test was positive in 11 (12.8%) patients and patch testing was positive in 71 (70%). Parthenium hysterophorus was the most common allergen implicated and was positive in three (4%) photo-patch and 52 (52%) patch tests. Other positive photo-patch test allergens were perfume mix, balsam of Peru, thiuram mix, Compositae mix and promethazine hydrochloride. Other common patch test allergens were parthenolide, colophony, fragrance mix and p-phenylenediamine (PPD) base. In the Indian population parthenium and perfume mix are the most common photoallergens in patients with dermatitis over photo-exposed areas, while parthenium, colophony, fragrance mix and PPD are the common positive allergens. © 2016 The Australasian College of Dermatologists.

Patch-based models and algorithms for image processing: a review of the basic principles and methods, and their application in computed tomography.

PubMed

Karimi, Davood; Ward, Rabab K

2016-10-01

Image models are central to all image processing tasks. The great advancements in digital image processing would not have been made possible without powerful models which, themselves, have evolved over time. In the past decade, "patch-based" models have emerged as one of the most effective models for natural images. Patch-based methods have outperformed other competing methods in many image processing tasks. These developments have come at a time when greater availability of powerful computational resources and growing concerns over the health risks of the ionizing radiation encourage research on image processing algorithms for computed tomography (CT). The goal of this paper is to explain the principles of patch-based methods and to review some of their recent applications in CT. We first review the central concepts in patch-based image processing and explain some of the state-of-the-art algorithms, with a focus on aspects that are more relevant to CT. Then, we review some of the recent application of patch-based methods in CT. Patch-based methods have already transformed the field of image processing, leading to state-of-the-art results in many applications. More recently, several studies have proposed patch-based algorithms for various image processing tasks in CT, from denoising and restoration to iterative reconstruction. Although these studies have reported good results, the true potential of patch-based methods for CT has not been yet appreciated. Patch-based methods can play a central role in image reconstruction and processing for CT. They have the potential to lead to substantial improvements in the current state of the art.

Safety of fentanyl initiation according to past opioid exposure among patients newly prescribed fentanyl patches

PubMed Central

Friesen, Kevin J.; Woelk, Cornelius; Bugden, Shawn

2016-01-01

Background: Although a convenient opioid delivery system, transdermal fentanyl patches have caused several deaths and resulted in safety warnings reminding prescribers that fentanyl patches should be prescribed only for patients who have adequate prior exposure to opioids. We conducted a longitudinal analysis of the safety of fentanyl initiation by examining past opioid exposure among patients newly prescribed fentanyl patches. Methods: We identified all patients in the province of Manitoba who were newly prescribed fentanyl patches between Apr. 1, 2001, and Mar. 31, 2013. We converted all prior opioid use to oral morphine equivalents and determined the average daily dose in the 7–30 days before initial fentanyl patch use. Fentanyl initiation was considered unsafe if the patient’s pre-fentanyl opioid exposure was below the recommended level. Results: We identified 11 063 patients who began using fentanyl patches during the study period. Overall, fentanyl initiation was deemed unsafe in 74.1% of cases because the patient’s prior opioid exposure was inadequate. Women and patients 65 years of age and older were more likely than men and younger patients, respectively, to have inadequate prior opioid exposure (p < 0.001 for each comparison). The proportion of patients who had unsafe prescriptions for fentanyl patches decreased significantly over the study period, from 87.0% in 2001 to 50.0% in 2012 (p < 0.001). Interpretation: The safety of fentanyl initiation improved over the study period, but still half of fentanyl patch prescriptions were written for patients with inadequate prior opioid exposure. Review of prior opioid exposure may be a simple but important way to improve the safe use of fentanyl patches. PMID:27044480

Mucoadhesive Fenretinide Patches for Site-specific Chemoprevention of Oral Cancer: Enhancement of Oral Mucosal Permeation of Fenretinide by Co-incorporation of Propylene Glycol and Menthol

PubMed Central

Wu, Xiao; Desai, Kashappa-Goud H.; Mallery, Susan R.; Holpuch, Andrew S.; Phelps, Maynard P.; Schwendeman, Steven P.

2012-01-01

The objective of this study was to enhance oral mucosal permeation of fenretinide by co-incorporation of propylene glycol (PG) and menthol in fenretinide/Eudragit® RL PO mucoadhesive patches. Fenretinide is an extremely hydrophobic chemopreventive compound with poor tissue permeability. Co-incorporation of 5-10 wt% PG (mean Js = 16-23 μg cm−2 h−1; 158-171 μg fenretinide/g tissue) or 1-10 wt% PG + 5 wt% menthol (mean Js = 18-40 μg cm−2 h−1; 172-241 μg fenretinide/g tissue) in fenretinide/Eudragit® RL PO patches led to significant ex vivo fenretinide permeation enhancement (p < 0.001). Addition of PG above 2.5 wt% in the patch resulted in significant cellular swelling in the buccal mucosal tissues. These alterations were ameliorated by combining both enhancers and reducing PG level. After buccal administration of patches in rabbits, in vivo permeation of fenretinide across the oral mucosa was greater (~43 μg fenretinide/g tissue) from patches that contained optimized permeation enhancer content (2.5 wt% PG + 5 wt% menthol) relative to permeation obtained from enhancer-free patch (~ 17 μg fenretinide/g tissue) (p < 0.001). In vitro and in vivo release of fenretinide from patch was not significantly increased by co-incorporation of permeation enhancers, indicating that mass transfer across the tissue, and not the patch, largely determined the permeation rate control in vivo. As a result of its improved permeation and its lack of deleterious local effects, the mucoadhesive fenretinide patch co-incorporated with 2.5 wt% PG + 5 wt% menthol represents an important step in the further preclinical evaluation of oral site-specific chemoprevention strategies with fenretinide. PMID:22280430

Travel time tomography with local image regularization by sparsity constrained dictionary learning

NASA Astrophysics Data System (ADS)

Bianco, M.; Gerstoft, P.

2017-12-01

We propose a regularization approach for 2D seismic travel time tomography which models small rectangular groups of slowness pixels, within an overall or `global' slowness image, as sparse linear combinations of atoms from a dictionary. The groups of slowness pixels are referred to as patches and a dictionary corresponds to a collection of functions or `atoms' describing the slowness in each patch. These functions could for example be wavelets.The patch regularization is incorporated into the global slowness image. The global image models the broad features, while the local patch images incorporate prior information from the dictionary. Further, high resolution slowness within patches is permitted if the travel times from the global estimates support it. The proposed approach is formulated as an algorithm, which is repeated until convergence is achieved: 1) From travel times, find the global slowness image with a minimum energy constraint on the pixel variance relative to a reference. 2) Find the patch level solutions to fit the global estimate as a sparse linear combination of dictionary atoms.3) Update the reference as the weighted average of the patch level solutions.This approach relies on the redundancy of the patches in the seismic image. Redundancy means that the patches are repetitions of a finite number of patterns, which are described by the dictionary atoms. Redundancy in the earth's structure was demonstrated in previous works in seismics where dictionaries of wavelet functions regularized inversion. We further exploit redundancy of the patches by using dictionary learning algorithms, a form of unsupervised machine learning, to estimate optimal dictionaries from the data in parallel with the inversion. We demonstrate our approach on densely, but irregularly sampled synthetic seismic images.

Is Decellularized Porcine Small Intestine Sub-mucosa Patch Suitable for Aortic Arch Repair?

PubMed Central

Corno, Antonio F.; Smith, Paul; Bezuska, Laurynas; Mimic, Branko

2018-01-01

Introduction: We reviewed our experience with decellularized porcine small intestine sub-mucosa (DPSIS) patch, recently introduced for congenital heart defects. Materials and Methods: Between 10/2011 and 04/2016 a DPSIS patch was used in 51 patients, median age 1.1 months (5 days to 14.5 years), for aortic arch reconstruction (45/51 = 88.2%) or aortic coarctation repair (6/51 = 11.8%). All medical records were retrospectively reviewed, with primary endpoints interventional procedure (balloon dilatation) or surgery (DPSIS patch replacement) due to patch-related complications. Results: In a median follow-up time of 1.5 ± 1.1 years (0.6–2.3years) in 13/51 patients (25.5%) a re-intervention, percutaneous interventional procedure (5/51 = 9.8%) or re-operation (8/51 = 15.7%) was required because of obstruction in the correspondence of the DPSIS patch used to enlarge the aortic arch/isthmus, with median max velocity flow at Doppler interrogation of 4.0 ± 0.51 m/s. Two patients required surgery after failed interventional cardiology. The mean interval between DPSIS patch implantation and re-intervention (percutaneous procedure or re-operation) was 6 months (1–17 months). While there were 3 hospital deaths (3/51 = 5.9%) not related to the patch implantation, no early or late mortality occurred for the subsequent procedure required for DPSIS patch interventional cardiology or surgery. The median max velocity flow at Doppler interrogation through the aortic arch/isthmus for the patients who did not require interventional procedure or surgery was 1.7 ± 0.57 m/s. Conclusions: High incidence of re-interventions with DPSIS patch for aortic arch and/or coarctation forced us to use alternative materials (homografts and decellularized gluteraldehyde preserved bovine pericardial matrix). PMID:29900163

Influence of Land Mosaic Composition and Structure on Patchy Populations: The Case of the Water Vole (Arvicola sapidus) in Mediterranean Farmland

PubMed Central

Pita, Ricardo; Mira, António; Beja, Pedro

2013-01-01

The ability of patchy populations to persist in human-dominated landscapes is often assessed using focal patch approaches, in which the local occurrence or abundance of a species is related to the properties of individual patches and the surrounding landscape context. However, useful additional insights could probably be gained through broader, mosaic-level approaches, whereby whole land mosaics with contrasting patch-network and matrix characteristics are the units of investigation. In this study we addressed this issue, analysing how the southern water vole (Arvicola sapidus) responds to variables describing patch-network and matrix properties within replicated Mediterranean farmland mosaics, across a gradient of agricultural intensification. Patch-network characteristics had a dominant effect, with the total amount of habitat positively influencing both the occurrence of water voles and the proportion of area occupied in land mosaics. The proportions of patches and area occupied by the species were positively influenced by mean patch size, and negatively so by patch isolation. Matrix effects were weak, although there was a tendency for a higher proportion of occupied patches in more intensive, irrigated agricultural landscapes, particularly during the dry season. In terms of conservation, results suggest that water voles may be able to cope well with, or even be favoured by, the on-going expansion of irrigated agriculture in Mediterranean dry-lands, provided that a number of patches of wet herbaceous vegetation are maintained within the farmland mosaic. Overall, our study suggests that the mosaic-level approach may provide a useful framework to understand the responses of patchy populations to land use change. PMID:23875014

Social Familiarity Governs Prey Patch-Exploitation, - Leaving and Inter-Patch Distribution of the Group-Living Predatory Mite Phytoseiulus persimilis

PubMed Central

Zach, Gernot J.; Peneder, Stefan; Strodl, Markus A.; Schausberger, Peter

2012-01-01

Background In group-living animals, social interactions and their effects on other life activities such as foraging are commonly determined by discrimination among group members. Accordingly, many group-living species evolved sophisticated social recognition abilities such as the ability to recognize familiar individuals, i.e. individuals encountered before. Social familiarity may affect within-group interactions and between-group movements. In environments with patchily distributed prey, group-living predators must repeatedly decide whether to stay with the group in a given prey patch or to leave and search for new prey patches and groups. Methodology/Principal Findings Based on the assumption that in group-living animals social familiarity allows to optimize the performance in other tasks, as for example predicted by limited attention theory, we assessed the influence of social familiarity on prey patch exploitation, patch-leaving, and inter-patch distribution of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. P. persimilis is highly specialized on herbivorous spider mite prey such as the two-spotted spider mite Tetranychus urticae, which is patchily distributed on its host plants. We conducted two experiments with (1) groups of juvenile P. persimilis under limited food on interconnected detached leaflets, and (2) groups of adult P. persimilis females under limited food on whole plants. Familiar individuals of both juvenile and adult predator groups were more exploratory and dispersed earlier from a given spider mite patch, occupied more leaves and depleted prey more quickly than individuals of unfamiliar groups. Moreover, familiar juvenile predators had higher survival chances than unfamiliar juveniles. Conclusions/Significance We argue that patch-exploitation and -leaving, and inter-patch dispersion were more favorably coordinated in groups of familiar than unfamiliar predators, alleviating intraspecific competition and improving prey utilization and suppression. PMID:22900062

Social familiarity governs prey patch-exploitation, -leaving and inter-patch distribution of the group-living predatory mite Phytoseiulus persimilis.

PubMed

Zach, Gernot J; Peneder, Stefan; Strodl, Markus A; Schausberger, Peter

2012-01-01

In group-living animals, social interactions and their effects on other life activities such as foraging are commonly determined by discrimination among group members. Accordingly, many group-living species evolved sophisticated social recognition abilities such as the ability to recognize familiar individuals, i.e. individuals encountered before. Social familiarity may affect within-group interactions and between-group movements. In environments with patchily distributed prey, group-living predators must repeatedly decide whether to stay with the group in a given prey patch or to leave and search for new prey patches and groups. Based on the assumption that in group-living animals social familiarity allows to optimize the performance in other tasks, as for example predicted by limited attention theory, we assessed the influence of social familiarity on prey patch exploitation, patch-leaving, and inter-patch distribution of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. P. persimilis is highly specialized on herbivorous spider mite prey such as the two-spotted spider mite Tetranychus urticae, which is patchily distributed on its host plants. We conducted two experiments with (1) groups of juvenile P. persimilis under limited food on interconnected detached leaflets, and (2) groups of adult P. persimilis females under limited food on whole plants. Familiar individuals of both juvenile and adult predator groups were more exploratory and dispersed earlier from a given spider mite patch, occupied more leaves and depleted prey more quickly than individuals of unfamiliar groups. Moreover, familiar juvenile predators had higher survival chances than unfamiliar juveniles. We argue that patch-exploitation and -leaving, and inter-patch dispersion were more favorably coordinated in groups of familiar than unfamiliar predators, alleviating intraspecific competition and improving prey utilization and suppression.

A Pharmacokinetic Study of an Ibuprofen Topical Patch in Healthy Male and Female Adult Volunteers.

PubMed

Lewis, Fraser; Connolly, Mark P; Bhatt, Aomesh

2018-01-11

The pharmacokinetics of a novel locally applied ibuprofen topical patch was evaluated. Healthy subjects (n = 28) were administered a 200-mg ibuprofen patch every 24 hours for 5 days, and steady-state pharmacokinetics was determined. The amount of ibuprofen remaining in the patch following each patch removal was also assessed. The maximum steady-state drug concentration and area under the concentration curve from time 0 on day 5 (t = 0) to the 24-hours sample on day 6 were 514 ng/mL (95% CI 439 to 603 ng/mL) and 9.78 kg·h/mL (95% CI 8.43 to 11.4 kg·h/mL), respectively. Maximum ibuprofen concentration on day 5 occurred at 20 hours post-patch application. No evidence of drug accumulation was observed, and steady state was achieved between days 2 and 5. Ibuprofen levels attenuated rapidly to baseline within 24 hours after treatment discontinuation. The amount of ibuprofen remaining in the patch was high (≥80%). Treatment-emergent adverse events were generally mild, with the most prevalent being headache (n = 6; 21.4%). Only 4 TEAEs were considered related to the ibuprofen patch: paresthesia (n = 1), headache (n = 2), and pruritic rash (n = 1). The study found that the systematic absorption of ibuprofen from a 200-mg patch was low and that the levels of ibuprofen leaving the patch over a 24-hour period are consistent with levels required for therapeutic relief as shown in other studies. © 2018, The American College of Clinical Pharmacology.

Circular free-electron laser

DOEpatents

Brau, Charles A.; Kurnit, Norman A.; Cooper, Richard K.

1984-01-01

A high efficiency, free electron laser utilizing a circular relativistic electron beam accelerator and a circular whispering mode optical waveguide for guiding optical energy in a circular path in the circular relativistic electron beam accelerator such that the circular relativistic electron beam and the optical energy are spatially contiguous in a resonant condition for free electron laser operation. Both a betatron and synchrotron are disclosed for use in the present invention. A free electron laser wiggler is disposed around the circular relativistic electron beam accelerator for generating a periodic magnetic field to transform energy from the circular relativistic electron beam to optical energy.

Fentanyl Patch Can Be Deadly to Children

MedlinePlus

... Products For Consumers Home For Consumers Consumer Updates Fentanyl Patch Can Be Deadly to Children Share Tweet ... from accidental exposure to a skin patch containing fentanyl, a powerful pain reliever. As a result of ...

Orbital implant exposure treatment with porcine dermal collagen patching.

PubMed

Alwitry, A; Burns, S J; Abercrombie, L C

2006-09-01

To present a small case series of orbital implant exposures treated with porcine dermal collagen (Permacol, Tissue Science Laboratories PLC, Aldershot, Hants, UK) patching. A retrospective chart review of three cases of orbital implant exposure treated with Permacol patching. Three cases were identified. There were 4 operative episodes of Permacol patching (one socket had two attempts at permacol patching). In all 4 cases the patch rapidly failed and melted away leaving behind the orbital implant exposure. All 3 patients required implant removal. Orbital implant exposure remains a major long-term complication of evisceration and enucleation procedures. On the basis of our experience, we would not recommend using Permacol as a non-autologous material for covering exposed Medpor (Medpor, Porex Surgical, Atlanta, Georgia, USA) orbital implants. Further study is required to fully assess the safety and efficacy profile of Permacol in socket surgery.

Suspended Patch Antenna Array With Electromagnetically Coupled Inverted Microstrip Feed

NASA Technical Reports Server (NTRS)

Simons, Rainee N.

2000-01-01

The paper demonstrates a four-element suspended patch antenna array, with a parasitic patch layer and an electromagnetically coupled inverted microstrip feed, for linear polarization at K-Band frequencies. This antenna has the following advantages over conventional microstrip antennas: First, the inverted microstrip has lower attenuation than conventional microstrip; hence, conductor loss associated with the antenna corporate feed is lower resulting in higher gain and efficiency. Second, conventional proximity coupled patch antennas require a substrate for the feed and a superstrate for the patch. However, the inverted microstrip fed patch antenna makes use of a single substrate, and hence, is lightweight and low cost. Third, electromagnetic coupling results in wider bandwidth. Details regarding the design and fabrication will be presented as well as measured results including return loss, radiation patterns and cross-polarization levels.

Rotator Cuff Repair with a Tendon-Fibrocartilage-Bone Composite Bridging Patch

PubMed Central

Ji, Xiaoxi; Chen, Qingshan; Thoreson, Andrew R.; Qu, Jin; An, Kai-Nan; Amadio, Peter C.; Steinmann, Scott P.; Zhao, Chunfeng

2015-01-01

Background To compare the mechanical performance of a rotator cuff repaired with a novel tendon-fibrocartilage-bone composite bridging patch vs the traditional Mason-Allen repair in an in vitro canine model. Methods Twenty shoulders and 10 bridging patches from patellar tendon were harvested. The patches were trimmed and sliced into 2 layers. An infraspinatus tendon tear was created in each shoulder. Modified Mason-Allen sutures were used to repair the infraspinatus tendon to the greater tuberosity, with or without the bridging patch (bridging patch group and controls, respectively). Shoulders were loaded to failure under displacement control at a rate of 0.5mm/sec. Findings The ultimate tensile load was significantly higher in the bridging patch group than control (mean [SD], 365.46 [36.45] vs 272.79 [48.88] N; P<.001). Stiffness at the greater tuberosity repair site and the patch-infraspinatus tendon repair site was significantly higher than the control repair site (93.96 [27.72] vs 42.62 [17.48] N/mm P<.001; 65.94 [24.51] vs 42.62 [17.48] N/mm P=.02, respectively). Interpretation The tendon-fibrocartilage-bone composite bridging patch achieved higher ultimate tensile load and stiffness at the patch–greater tuberosity repair site compared with traditional repair in a canine model. This composite tissue transforms the traditional tendon-to-bone healing interface (with dissimilar tissues) into a pair of bone-to-bone and tendon-to-tendon interfaces, which may improve healing quality and reduce retear rate. PMID:26190097

Rivastigmine Patch in Chinese Patients with Probable Alzheimer's disease: A 24-week, Randomized, Double-Blind Parallel-Group Study Comparing Rivastigmine Patch (9.5 mg/24 h) with Capsule (6 mg Twice Daily).

PubMed

Zhang, Zhen-Xin; Hong, Zhen; Wang, Yan-Ping; He, Li; Wang, Ning; Zhao, Zhong-Xin; Zhao, Gang; Shang, Lan; Weisskopf, Marianne; Callegari, Francesca; Strohmaier, Christine

2016-06-01

To compare the once-daily rivastigmine patch 9.5 mg/24 h (10 cm(2) ) versus twice-daily capsule (12 mg/day) in Chinese patients with probable Alzheimer's disease (AD) (mini-mental state examination [MMSE] scores of 10-20). The primary objective was to demonstrate the noninferiority of patch to capsule in Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog) change from baseline to 24 week. Secondary endpoints included cognition (MMSE), overall clinical response (Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change [ADCS-CGIC]), activities of daily living (Alzheimer's Disease Cooperative Study-Activities of Daily Living [ADCS-ADL]), behavior (Neuropsychiatric Inventory [NPI-12]), and safety. Similar cognitive improvement was observed in both patch (n = 248) and capsule (n = 253) groups. Statistical noninferiority for ADAS-Cog was not established (least-square means difference, 0.1; 95% confidence interval, -1.2; 1.5). Considering all efficacy parameters into account, both treatments showed similar performance at Week 24. Treatment-related adverse events (AEs) were lower for patch (39.7%) compared with capsule (49.8%). Application site pruritus was reported in 10.9% of patients receiving patch; most cases were mild. Gastrointestinal AEs including nausea, vomiting, and diarrhea occurred less frequently in the patch group (15.8% vs. 28.7%). Rivastigmine patch 9.5 mg/24 h is effective and well tolerated in Chinese patients with probable AD. © 2016 John Wiley & Sons Ltd.

A Comparison of the Performance and Application Differences Between Manual and Automated Patch-Clamp Techniques

PubMed Central

Yajuan, Xiao; Xin, Liang; Zhiyuan, Li

2012-01-01

The patch clamp technique is commonly used in electrophysiological experiments and offers direct insight into ion channel properties through the characterization of ion channel activity. This technique can be used to elucidate the interaction between a drug and a specific ion channel at different conformational states to understand the ion channel modulators’ mechanisms. The patch clamp technique is regarded as a gold standard for ion channel research; however, it suffers from low throughput and high personnel costs. In the last decade, the development of several automated electrophysiology platforms has greatly increased the screen throughput of whole cell electrophysiological recordings. New advancements in the automated patch clamp systems have aimed to provide high data quality, high content, and high throughput. However, due to the limitations noted above, automated patch clamp systems are not capable of replacing manual patch clamp systems in ion channel research. While automated patch clamp systems are useful for screening large amounts of compounds in cell lines that stably express high levels of ion channels, the manual patch clamp technique is still necessary for studying ion channel properties in some research areas and for specific cell types, including primary cells that have mixed cell types and differentiated cells that derive from induced pluripotent stem cells (iPSCs) or embryonic stem cells (ESCs). Therefore, further improvements in flexibility with regard to cell types and data quality will broaden the applications of the automated patch clamp systems in both academia and industry. PMID:23346269

Effect of permeation enhancers in the mucoadhesive buccal patches of salbutamol sulphate for unidirectional buccal drug delivery

PubMed Central

Prasanth, V.V.; Puratchikody, A.; Mathew, S.T.; Ashok, K.B.

2014-01-01

The purpose of this work was to study the effect of various permeation enhancers on the permeation of salbutamol sulphate (SS) buccal patches through buccal mucosa in order to improve the bioavailability by avoiding the first pass metabolism in the liver and possibly in the gut wall and also achieve a better therapeutic effect. The influence of various permeation enhancers, such as dimethyl sulfoxide (DMSO), linoleic acid (LA), isopropyl myristate (IPM) and oleic acid (OA) on the buccal absorption of SS from buccal patches containing different polymeric combinations such as hydroxypropyl methyl cellulose (HPMC), carbopol, polyvinyl alcohol (PVA), polyvinyl pyrollidone (PVP), sodium carboxymethyl cellulose (NaCMC), acid and water soluble chitosan (CHAS and CHWS) and Eudragit-L100 (EU-L100) was investigated. OA was the most efficient permeation enhancer increasing the flux greater than 8-fold compared with patches without permeation enhancer in HPMC based buccal patches when PEG-400 was used as the plasticizer. LA also exhibited a better permeation enhancing effect of over 4-fold in PVA and HPMC based buccal patches. In PVA based patches, both OA and LA were almost equally effective in improving the SS permeation irrespective of the plasticizer used. DMSO was more effective as a permeation enhancer in HPMC based patches when PG was the plasticizer. IPM showed maximum permeation enhancement of greater than 2-fold when PG was the plasticizer in HPMC based buccal patches. PMID:25657797

Evaluation of a mucoadhesive buccal patch for delivery of peptides: in vitro screening of bioadhesion.

PubMed

Li, C; Bhatt, P P; Johnston, T P

1998-10-01

We have assessed the bioadhesive properties of several different mucoadhesive buccal patches. The patches consisted of custom coformulations of silicone polymers and Carbopol 974P. The contact angle of water was measured for each of the test formulations, using an ophthalmic shadow scope. The corresponding work of adhesion between the water and the patches (W1), and between the patches and freshly-excised rabbit buccal mucosa (W2) was then calculated, using a modification of Dupre's equation. The bioadhesive strength between the patches and excised rabbit buccal mucosa was also assessed. The results of the contact-angle measurements indicated that the contact angle decreased with an increase in the amount of Carbopol in the formulation. Additionally, the calculated values of both W1 and W2 increased with an increase in the amount of Carbopol in the buccal-patch formulations. A correlation (r not equal to 0.9808) was found between the measured contact angle and the calculated values for W2. The direct measurement of the force required to separate a buccal patch from excised rabbit buccal mucosa with the INSTRON demonstrated that the adhesive strength increased with an increase in the amount of Carbopol. This preliminary study has shown that the measurement of contact angles alone may provide a useful technique for estimating the work of adhesion, and may serve as a convenient and rapid screening procedure to identify potential mucoadhesive buccal-patch formulations.

Trichloroethylene Hypersensitivity Syndrome Is Potentially Mediated through Its Metabolite Chloral Hydrate.

PubMed

Huang, Yongshun; Xia, Lihua; Wu, Qifeng; Zeng, Zifang; Huang, Zhenlie; Zhou, Shanyu; Jin, Jiachun; Huang, Hanlin

2015-01-01

We documented previously the entity of trichloroethylene (TCE) hypersensitivity syndrome (THS) in occupational workers. To identify the culprit causative compound, determine the type of hypersensitivity of THS, and establish a screening test for subjects at risk of THS. TCE and its main metabolites chloral hydrate (CH), trichloroethanol (TCOH) and trichloroacetic acid (TCA) were used as allergens at different concentrations in skin patch tests. The study included 19 case subjects diagnosed with occupational THS, 22 control healthy workers exposed to TCE (exposure >12 weeks), and 20 validation new workers exposed to TCE for <12 weeks free of THS. All subjects were followed-up for 12 weeks after the patch test. The highest patch test positive rate in subjects with THS was for CH, followed by TCOH, TCA and TCE. The CH patch test positive rate was 100% irrespective of CH concentrations (15%, 10% and 5%). The TCOH patch test positive rate was concentration-dependent (89.5%, 73.7% and 52.6% for 5%, 0.5% and 0.05%, respectively). Lower patch test positive rates were noted for TCA and TCE. All patch tests (including four allergens) were all negative in each of the 22 control subjects. None of the subjects of the validation group had a positive 15% CH patch test. Chloral hydrate seems to be the culprit causative compound of THS and type IV seems to be the major type of hypersensitivity of THS. The CH patch test could be potentially useful for screening workers at risk of THS.

Predation and landscape characteristics independently affect reef fish community organization.

PubMed

Stier, Adrian C; Hanson, Katharine M; Holbrook, Sally J; Schmitt, Russell J; Brooks, Andrew J

2014-05-01

Trophic island biogeography theory predicts that the effects of predators on prey diversity are context dependent in heterogeneous landscapes. Specifically, models predict that the positive effect of habitat area on prey diversity should decline in the presence of predators, and that predators should modify the partitioning of alpha and beta diversity across patchy landscapes. However, experimental tests of the predicted context dependency in top-down control remain limited. Using a factorial field experiment we quantify the effects of a focal predatory fish species (grouper) and habitat characteristics (patch size, fragmentation) on the partitioning of diversity and assembly of coral reef fish communities. We found independent effects of groupers and patch characteristics on prey communities. Groupers reduced prey abundance by 50% and gamma diversity by 45%, with a disproportionate removal of rare species relative to common species (64% and 36% reduction, respectively; an oddity effect). Further, there was a 77% reduction in beta diversity. Null model analysis demonstrated that groupers increased the importance of stochastic community assembly relative to patches without groupers. With regard to patch size, larger patches contained more fishes, but a doubling of patch size led to a modest (36%) increase in prey abundance. Patch size had no effect on prey diversity; however, fragmented patches had 50% higher species richness and modified species composition relative to unfragmented patches. Our findings suggest two different pathways (i.e., habitat or predator shifts) by which natural and/or anthropogenic processes can drive variation in fish biodiversity and community assembly.

In silico identification of functional regions in proteins.

PubMed

Nimrod, Guy; Glaser, Fabian; Steinberg, David; Ben-Tal, Nir; Pupko, Tal

2005-06-01

In silico prediction of functional regions on protein surfaces, i.e. sites of interaction with DNA, ligands, substrates and other proteins, is of utmost importance in various applications in the emerging fields of proteomics and structural genomics. When a sufficient number of homologs is found, powerful prediction schemes can be based on the observation that evolutionarily conserved regions are often functionally important, typically, only the principal functionally important region of the protein is detected, while secondary functional regions with weaker conservation signals are overlooked. Moreover, it is challenging to unambiguously identify the boundaries of the functional regions. We present a new methodology, called PatchFinder, that automatically identifies patches of conserved residues that are located in close proximity to each other on the protein surface. PatchFinder is based on the following steps: (1) Assignment of conservation scores to each amino acid position on the protein surface. (2) Assignment of a score to each putative patch, based on its likelihood to be functionally important. The patch of maximum likelihood is considered to be the main functionally important region, and the search is continued for non-overlapping patches of secondary importance. We examined the accuracy of the method using the IGPS enzyme, the SH2 domain and a benchmark set of 112 proteins. These examples demonstrated that PatchFinder is capable of identifying both the main and secondary functional patches. The PatchFinder program is available at: http://ashtoret.tau.ac.il/~nimrodg/

Circular stapler introducer: a novel device to facilitate stapled colorectal anastomosis.

PubMed

Guweidhi, Ahmed; Steffen, Rudolf; Metzger, Alejandro; Teuscher, Jürg; Flückiger, Petra; Z'graggen, Kaspar

2009-04-01

A circular stapler introducer was developed to protect the head of the circular stapler and enable atraumatic introduction and advancement of the circular stapler without interfering with the application and safety of an anastomosis. In a Phase I prospective study, we tested the feasibility and safety of the novel circular stapler introducer device in 60 consecutive patients undergoing left-sided colorectal resections. The median distance of the anastomoses from the anal verge was 12 cm (7-20, n = 60). Total morbidity was 15 percent. No mortality was observed. Handling of the circular stapler introducer was considered nonproblematic by all surgeons who participated in the study. No interference of the circular stapler introducer with the circular stapling devices used was encountered. The advancement of the stapler into the end of the colorectal stump was always possible with the aid of the circular stapler introducer. Use of the circular stapler introducer facilitates the double-stapling technique of colorectal anastomosis. The circular stapler introducer has great potential and should be tested in larger studies.