Deep vein thrombosis (DVT) is a common and potentially devastating condition affecting between 350,000 and nearly 1 million new patients in the US annually. The most common complication is Post Thrombotic Syndrome (PTS) affecting 25-50% within 2 years of the onset of the thrombotic episode. The current standard of care for both acute and chronic DVT is to prevent progression rather than resolution of DVT. We report the technical and clinical outcomes in patients aggressively treated for chronic, occlusive DVT causing Post Thrombotic syndrome. A single center registry and retrospective chart review of patients suffering from PTS that were treated for chronic occlusive DVT. Case review data were collected, including DVT history, procedural information, immediate technical outcomes, symptomatic improvement, and ultrasound follow-up at 1, 3, 6, and 12 months and yearly thereafter. 106 patients and 114 limbs were treated, including 74 M and 42 F (mean age 57; range 13–96). 11 upper and 103 lower extremities with IVC involvement in 25 were included. All patients had symptoms > 1 month (range 1 month–12 years). Technical success was defined as A) ability to completely cross the occlusion and B) ability to restore flow in the venous segments. 112 of 114 occlusions were successfully crossed (98%) with venous flow established in 110 of 114 limbs crossed (97%). 2 endpoints were used for clinical success: patency on ultrasound and symptomatic improvement. 18 of 114 limbs were completely lost to follow-up. Of the remaining 96 limbs, 89 (93%) reported significant improvement, 7 (7%) were unchanged, and none were worse. Follow-up ultrasound exams demonstrated patency as follows: 1 month 99% (78 of 79 limbs), 3 months 98% (55 of 56), 6 months 97% (49 of 50), 12 months 100% (27 of 27), 2 yr 100% (9 of 9), 3 yrs 100% (2 of 2). No major adverse events were noted. Chronic, occlusive DVT causing significant quality of life limitations from PTS, can safely and effectively be treated with excellent short to mid term technical and clinical outcomes.

Learning ObjectivesUltrasound guided inguinal lymph node access for lymphangiography is safe and effective while significantly reducing time to completion.BackgroundLymphangiography can be used to evaluate patients with suspected lymphatic disease. Its use is limited by the technical challenges faced by the physician as well as the length of the procedure. Conventional lymphangiography (CL) begins with the interdigital injection of dye, followed by surgical exposure of a lymphatic vessel. After an often difficult cannulation of the vessel, ethiodized oil is slowly infused via pump, to opacify the lymphatics. An extremely tedious procedure, it often requires hours and sometimes days to complete. Modern advances in imaging such as MR have replaced CL as the diagnostic test of choice. CL is most often performed when intervention, such as thoracic duct embolization, is requested. We present an alternative approach to CL using ultrasound-guided access of inguinal lymph nodes for lymphangiography with subsequent cannulation of lymphatic vessels. This approach has proven successful in animal studies using ultrasound-guided injection of mesenteric nodes. The method presented here describes injection of inguinal lymph nodes leading to successful lymphangiography without the need for surgical exposure.Clinical Findings/Procedure DetailsUltrasonography was used to localize an inguinal lymph node, which was accessed with a 25 G needle. Non-ionic contrast was gently injected to confirm lymphatic visualization followed by gentle hand administration of ethiodized oil. Standard pelvic, abdominal and chest radiographs were obtained to evaluate for the presence of a thoracic duct leak.Conclusion and/or Teaching PointsThe alternative method presented here allows for successful lymphangiography to be performed more expediently than CL. The lack of pedal surgical cutdown is better tolerated and allows for rapid patient recovery. Learning ObjectivesUltrasound guided inguinal lymph node access for lymphangiography is safe and effective while significantly reducing time to completion. Ultrasound guided inguinal lymph node access for lymphangiography is safe and effective while significantly reducing time to completion. BackgroundLymphangiography can be used to evaluate patients with suspected lymphatic disease. Its use is limited by the technical challenges faced by the physician as well as the length of the procedure. Conventional lymphangiography (CL) begins with the interdigital injection of dye, followed by surgical exposure of a lymphatic vessel. After an often difficult cannulation of the vessel, ethiodized oil is slowly infused via pump, to opacify the lymphatics. An extremely tedious procedure, it often requires hours and sometimes days to complete. Modern advances in imaging such as MR have replaced CL as the diagnostic test of choice. CL is most often performed when intervention, such as thoracic duct embolization, is requested. We present an alternative approach to CL using ultrasound-guided access of inguinal lymph nodes for lymphangiography with subsequent cannulation of lymphatic vessels. This approach has proven successful in animal studies using ultrasound-guided injection of mesenteric nodes. The method presented here describes injection of inguinal lymph nodes leading to successful lymphangiography without the need for surgical exposure. Lymphangiography can be used to evaluate patients with suspected lymphatic disease. Its use is limited by the technical challenges faced by the physician as well as the length of the procedure. Conventional lymphangiography (CL) begins with the interdigital injection of dye, followed by surgical exposure of a lymphatic vessel. After an often difficult cannulation of the vessel, ethiodized oil is slowly infused via pump, to opacify the lymphatics. An extremely tedious procedure, it often requires hours and sometimes days to complete. Modern advances in imaging such as MR have replaced CL as the diagnostic test of choice. CL is most often performed when intervention, such as thoracic duct embolization, is requested. We present an alternative approach to CL using ultrasound-guided access of inguinal lymph nodes for lymphangiography with subsequent cannulation of lymphatic vessels. This approach has proven successful in animal studies using ultrasound-guided injection of mesenteric nodes. The method presented here describes injection of inguinal lymph nodes leading to successful lymphangiography without the need for surgical exposure. Clinical Findings/Procedure DetailsUltrasonography was used to localize an inguinal lymph node, which was accessed with a 25 G needle. Non-ionic contrast was gently injected to confirm lymphatic visualization followed by gentle hand administration of ethiodized oil. Standard pelvic, abdominal and chest radiographs were obtained to evaluate for the presence of a thoracic duct leak. Ultrasonography was used to localize an inguinal lymph node, which was accessed with a 25 G needle. Non-ionic contrast was gently injected to confirm lymphatic visualization followed by gentle hand administration of ethiodized oil. Standard pelvic, abdominal and chest radiographs were obtained to evaluate for the presence of a thoracic duct leak. Conclusion and/or Teaching PointsThe alternative method presented here allows for successful lymphangiography to be performed more expediently than CL. The lack of pedal surgical cutdown is better tolerated and allows for rapid patient recovery. The alternative method presented here allows for successful lymphangiography to be performed more expediently than CL. The lack of pedal surgical cutdown is better tolerated and allows for rapid patient recovery.

Epitaxially grown GaAs (p- and n-type) and n-Si were bombarded with low energy Ar-ions. Current voltage measurements on Schottky barrier diodes fabricated on the sputtered p-GaAs (Sc) and n-Si (Pd) showed that the series resistance and ideality factor were increased as the Arion dose was increased. The respective increase and decrease in barrier heights of Sc/p-GaAs and Pd/n-Si diodes were attributed to the presence of donor-type surface states in the bombarded material. The barrier heights of Au Schottky diodes made on n-GaAs changed nonmonotonically with Ar-ion sputter voltage. Variations of barrier height in the 0-1 kV range were explained by the introduction of donor-type defects. We demonstrated that the introduction of high concentrations of continuous level defects above 1 kV resulted in Fermi level pinning to become the dominant mechanism for controlling the effective barrier of current transport. Our results have shown that Schottky barrier properties could be changed by controlled amounts by varying the bombarding ion dose or sputter voltage.

We report on the electrical properties of defects introduced in epitaxially grown n-Si by 1 keV He-, Ne-, and Ar-ion bombardment. Epitaxial layers with different O contents were used in this study. We demonstrate using deep level transient spectroscopy that the low energy ions introduced a family of similarly structured defects (DI) with electronic levels at ~0.20 eV below the conduction band. The introduction of this set of identical defects was not influenced by the presence of O. Ion bombardment of O-rich Si introduced another family of prominent traps (D2) with levels close to the middle of the band gap. Both sets of defects were thermally stable up to ~400 °C, and their annealing was accompanied by the introduction of a family of secondary defects (D3). The “D3” defects had levels at ~0.21 eV below the conduction band and were thermally stable at 650 °C. We have proposed that the “DI”, “D2”, and “D3” defects are higherorder vacancy clusters (larger than the divacancy) or complexes thereof.

Deep level transient spectroscopy (DLTS) was used to examine the metastability of a defect configuration in epitaxially grown boron-doped p-type Si. We report the detection of a new metastable defect Hα2 in p-Si following room temperature alpha particle irradiation. DLTS measurements coupled with bias-on/bias-off cooling cycles were used to study the annealing and introduction kinetics of this metastable defect. After removing Hα2 by zero-bias annealing at room temperature, it was re-introduced by reverse bias annealing in the 240-265 K temperature range under predominantly first order kinetics. The energy level and apparent capture cross section, as determined by DLTS, were E,+ 0.43 eV and 1.4 × 10−15 cm2, respectively.

Despite good progress in the study of charge transfer in conducting polymers, factors affecting electrical conductivity in terms of device applications are not entirely understood. We have investigated charge transfer in polyaniline (Pan) using DC measurements over the temperature range 300 < T (K) < 450, thermal analysis and Fourier transform infrared spectroscopy (FTIR). Positive and negative conductivity coefficients of the material over the specified temperature regime were displayed. The Montgomery and the four point probe methods were used for the electrical d.c. measurements for thin films and pellets respectively. FTIR results show molecular structure changes as a result of the annealing process and thermal analysis indicate the loss of moisture at around 373 K. (C) 2002 Published by Elsevier Science B.V.

Gold Schottky-barrier diodes (SBDs) were fabricated on vapor-phase-grown single-crystal ZnO. Deep-level transient spectroscopy, using these SBDs, revealed the presence of four electron traps, the major two having levels at 0.12 eV and 0.57 below the conduction band. Comparison with temperature-dependent Hall measurements suggests that the 0.12 eV level has a temperature activated capture cross section with a capture barrier of about 0.06 eV and that it may significantly contribute to the free-carrier density. Based on the concentrations of defects other than this shallow donor, we conclude that the quality of the vapor-phase-grown ZnO studied here supercedes that of other single-crystal ZnO reported up to now.

BOLD (Blind to the Optical Light Detectors) is an international initiative dedicated to the development of novel imaging detectors for UV solar observations. It relies on the diamond and nitride materials that have lately undergone key advances. The investigation is proposed in view of Solar Orbiter UV instruments, for which the expected properties of the new sensors—visible blindness and radiation hardness—will be highly beneficial. Solar Orbiter is a selected Flexi mission of the European Space Agency (ESA). Despite various improvements over the last few decades, the present UV detectors exhibit limitations inherent to their actual technology. Yet the utmost spatial resolution, temporal cadence, sensitivity, and photometric accuracy will be decisive for the forthcoming space solar missions. The advent of imagers made of a large bandgap semiconductor would surmount many weaknesses, thus opening up new prospects and making the instruments cheaper. As for the ESA Solar Orbiter, the aspiration for wide bandgap semiconductor-based UV detectors is still more sensible, for the spacecraft will approach the Sun where the heat and the radiation fluxes are high. We depict motivations and present activities and programme to achieve revolutionary flight cameras within the Solar Orbiter schedule.

Recent rapid progress in SiGe-based heterostructures has opened the possibility to produce a new Si/Si1-xGex based family of electronic devices using Si processing techniques. The current fabrication of electronic devices tend towards processing for suppressing defect formation during SiGe-based microelectronic processes. In this paper recently published results on point defects in Si1-xGex will be reviewed. We have used deep level transient spectroscopy to study in detail the characterization and identification of the electrically active defects which are produced in n-type and p-type SiGe during particle irradiation, ion implantation, plasma etching, and electron-beam deposition (EB) and sputter deposition of metal Schottky contacts on SiGe. Several defect levels introduced in SiGe can be correlated with defects which have been identified in irradiation induced defects in Si. In addition coupling between the band gap changes with Ge concentration and defect engineering as well as the pinning behavior are also investigated.

Electrical conduction in thin films and pellets of polyaniline has been shown by several researchers to be temperature activated. Commercial polyaniline (Pan) obtained from Aldrich (HCl and CSA doped) and chemically synthesized (HCl doped) in our laboratory were used in this present work. The Kivelson, Mott's variable range hopping and Arrhenius laws were used to model conductivity in Pan. Charge transfer in Pan samples of different forms and dopant type were analyzed over the temperature ranges, 30 < T(K) < 300 and 300 < T(K) < 450. For temperatures below 60 K, application of currents in the range 2 x 10(-3)-2 x 10(-8) A show non-ohmic behavior; however, over the same current range, the current-voltage profile becomes ohmic as temperature rises to 300 K. It has been shown that the charge transfer characteristics of Pan is similar, despite of the type and dopant used. The Montgomery and four-point probe methods were used for DC measurements. (C) 2002 Published by Elsevier Science B.V.

The argon ion sputter yields of epitaxial Si0.84Ge0.16 films on a Si substrate are presented for different ion energies (0.5–5 keV) and angles of incidence (0–70°). The results were obtained by using atomic force microscopy (AFM) to determine the sputter depths of shielded samples. There was reasonable agreement between the experimental sputter yields and the predictions from the Sigmund theory. The results showed the applicability of this method using AFM to determine sputter yields of thin films. The surface topographies of the unbombarded and sputtered surfaces were characterised by AFM and were quantified in terms of the rms roughness. The results showed that very little topography developed on the surfaces due to the ion bombardment. The rms roughness exhibited no significant dependence on the ion energy or the angle of incidence. There was only a slight correlation with the ion dose density.

We have studied defects introduced in n-GaN during 25 keV hydrogen and 40 keV He implantation using deep level transient spectroscopy (DLTS). These measurements revealed that 25 keV hydrogen implantation introduces a complex set of electron traps, of which most are different to the defects observed after high-energy (MeV) electron and proton implantation. At least three of the defects detected after 25 keV proton implantation exhibit a metastable character in that they can be reproducibly removed and re-introduced during reverse and zero bias anneal cycles. Isochronal and isothermal annealing experiments yielded low activation energies of approximately 0.1 − 0.2 eV for both processes. By comparison, 40 keV He ion implantation introduced the same metastable defects, but in different relative concentrations.

We have implanted Ni/n-GaN Schottky contacts with 25 keV hydrogen ions (protons). The defects, thus, introduced were studied using deep level transient spectroscopy. We have found that 25 keV proton implantation introduces a complex set of electron traps in GaN, of which most are different to the defects observed after high-energy (MeV) electron and proton implantation. Two prominent defects that could clearly be distinguished from each other have energy levels at 0.22 and 0.30 eV below the conduction band. At least three of the defects detected after 25 keV proton implantation exhibit a metastable character in which they can be reproducibly removed and re-introduced during reverse and zero bias anneal cycles.

Using deep-level transient spectroscopy (DLTS), we have found that 1 MeV proton bombardment introduces the ER3, nitrogen vacancy related defect, at a rate of 290±50cm−1. Further, using capacitance–voltage (C–V) measurements, we have found that 1 MeV protons remove free carriers at a rate of 3880±380cm−1. However, when bombarding GaN with 0.5 keV protons, we did not observe the ER3 defect. We propose that 0.5 keV protons indeed introduce the ER3 defect, but that it is passivated by hydrogen.

We report the electronic properties, obtained by deep level transient spectroscopy (DLTS), of electron trap defects in n-GaN, grown by hydride vapour phase epitaxy (HVPE), metal-organic vapour phase epitaxy (MOVPE), reactive molecular beam epitaxy (RMBE) and, for the first time, epitaxial lateral overgrowth (ELO) MOVPE. Two prominent traps with energy levels at E-C - 0.27 eV and E-C - 0.61 eV, respectively, are introduced during all four methods. Their filling kinetics suggest that they are extended defects. On the other hand, the levels at E-C - 0.65 eV and E-C - 0.21 eV are only detected in HVPE and RMBE grown GaN, respectively, and appear to be characteristic of these methods.

Deep traps are studied in MBE grown n-AlxGa1−xN Schottky photodiodes using deep level transient spectroscopy (DLTS). These daylight blind UV photodetectors have cut-off wavelengths of 300 and 250nm, for x=0.12 and 0.41, respectively. Other investigations of deep centers are those by Gotz et al. who studied MOCVD Al0.12Ga0.88N (Appl. Phys. Lett. 69 (1996) 2379); and by Polyakov et al. who looked at p-AlGaN using an AlGaN/GaN heterojunction LED p–i–n structure (Solid State Electron. 43 (1999) 1929). Our photodiodes were MBE grown with carrier density (5–9)×1017cm−3. We detect two levels, EOA2 and EOA1 in each photodetector, below 320K, independent of the Al mole fraction, x. For AlxGa1−xN with x=0.41, EOA2 has a DLTS signature (EC–0.567eV; 1.1×10−14cm2) while the signature for the second defect, EOA1, is (EC–0.274eV; 3.1×10−13cm2). From a comparison with as-grown defects in MBE grown n-GaN, it would appear, based on DLTS signatures that EOA1 is the same as E1 (EC–0.234eV) observed by Wang et al. (Appl. Phys. Lett. 72 (1998) 1211) and EOA2 is the 0.61eV level reported by Gotz et al. (Appl. Phys. Lett. 69 (1996) 2379). Furthermore, proton irradiation introduces an additional electron trap, EpR1, at 0.187eV. We also determine that He-ions remove carriers in AlGaN, at a rate of 23770cm−1, eighty times higher than in GaN.

We have used deep-level transient spectroscopy (DLTS) to investigate the electron trap defects introduced in n-GaN during the fabrication of Pt Schottky contacts by electro-deposition, electron beam deposition and sputter deposition under three different deposition conditions. The results indicate that electro-deposition is the only one of these processes that does not introduce any defects. Diodes fabricated by this technique also have the best rectification properties. Both electron beam deposition and sputter deposition introduce electron traps in concentrations that increase towards the Pt/GaN interface. However, sputter deposition at a lower power and higher pressure results in significantly reduced defect concentrations and improved rectification properties.

Using deep level transient spectroscopy, we have investigated the electron trap defects introduced in n-GaN grown using the epitaxial lateral overgrowth technique during high energy electron irradiation from a Sr90 radionuclide source. The results indicate that the major electron-irradiation-induced defect labeled ER3 is not a single defect level but is made up of at least three defect levels (ER3b–ER3d). One of these defects, ER3d, has an activation energy and introduction rate of 0.22 eV and 0.43 cm−1, respectively. The total introduction rate of the three defects (ER3b–ER3d) is approximately 1.0 cm−1.