Search

Computed tomography angiography (PMCTA) is increasingly used in postmortem cases. Standardized validated protocols permit to compare different PMCTA images and make it more easily to defend a case in court. In addition to the well-known technique by Grabherr et al. (2011) which is using paraffin oil as a carrier substance, water-soluble polyethylene glycol 200 (PEG200) can be used in combination with the contrast agent Accupaque® 300. As to date, there exists no standardized protocol for the use of this contrast agent mixture, the aim of this study was to develop a protocol using it. Between 2012 and 2022, 23 PMCTA with PEG200 and Accupaque®300 were performed at the University Centre of Legal Medicine Lausanne (Switzerland) and the Institute of Forensic Medicine Munich (Germany). The images obtained were evaluated regarding the opacification of the vessels and possible artefacts. The best image quality was obtained with a mixing ratio of 1:15 (Accupaque®300:PEG200) and a perfusion volume of 1000 ml in the arterial, 1400 ml in the venous and 350 ml in the dynamic phase. The infusion rates described by Grabherr et al. were confirmed for the three phases. Overall, the opacification of the vessels was diagnostically sufficient. In 13 cases no opacification of the right coronary artery was observed due to a stratification artefact. By using the PMCTA protocol with PEG200 as a carrier, a good overall image quality can be achieved. This protocol offers the possibility to standardize PMCTA with PEG200. [ABSTRACT FROM AUTHOR]

Evanescently-coupled photodiodes were realised for high-power operation at a wavelength of 1.55 µm and wide-band operation beyond 30 GHz. Evanescent coupling allows for uniform carrier generation, which avoids electrical breakdown at the beginning of the active waveguide. The evanescently-coupled photodiodes, with an active length of 70 µm, reach a bandwidth of 40 GHz. Their average photocurrent at the -1 dB saturation point is 14 mA at 40 GHz. The evanescently-coupled photodiodes, with an active length of 120 µm, reach a bandwidth of 30 GHz. Their average photocurrent at the -1 dB saturation point is 22 mA at 40 GHz. The dual-depletion active region allows for reduced capacitance, and therefore higher bandwidth. The measured polarisation dependent loss is, on average, 1.2 dB on the 30 GHz devices. More work is needed to understand this high value, compared with the low theoretical value of 0.01 dB. [ABSTRACT FROM AUTHOR]

Describes a monolithic polarization-selective side-illuminated pin detector using the coupling properties of symmetric and asymmetric slab optical waveguides. Modal analysis of the proposed basic structure; Replacement of the symmetric waveguide with a multiple diluted waveguide optimized by a genetic algorithm coupled to a beam propagation method; Improvement in the performance of the device and the computer polarization ratio.

Resection of localized pancreatic head ductal adenocarcinoma (LPHDA) has a limited impact on survival. Mechanisms of improvement provided by preoperative chemoradiation therapy (CRT) remain under debate. This study analyzes the outcome of patients treated for LPHDA to delineate the benefits of CRT. Among 87 patients with LPHDA, 17 had a pancreaticoduodenectomy alone (group I). Thirty-nine with initially resectable cancers received CRT with 5-fluorouracil–based chemotherapy (group II). Thirty-one with initially unresectable cancers were similarly treated by CRT (group III). Patients in groups II and III were restaged after completion of CRT. In patients with resectable disease, resection was planned. Patients in groups I and II were statistically comparable in terms of age, sex, and pretherapeutic stage. Median survival and 2-year overall survival in group I were 13.7 months and 31%, respectively. In group II, 23 patients (59%) had a pancreaticoduodenectomy (group IIa) and 16 patients (41%) did not have resection (group IIb). Median survival and 2-year overall survival were as follows: group IIa, 26.6 months and 51%; and group IIb, 6.1 months and 0%, respectively. In group IIa, pathologic examination revealed eight major responses (35%) including two sterilized specimens, and none of the patients had locoregional recurrence. In group III, none of the patients had resection, and median survival was 8 months with one 2-year survivor. Patient selection appears to play a major role with regard to results achieved with preoperative CRT followed by pancreaticoduodenectomy. However, a high histologic response rate and excellent local control can also be achieved. [Copyright &y& Elsevier]

PURPOSE: Eighty percent of local recurrence after resection of rectal adenocarcinoma classically occurs within two years of surgery. Pretherapeutic staging is frequently limited to clinical examination, although the accuracy of endoanal ultrasonography has been demonstrated. The aim of this study was to report the long-term results of preoperative radiation therapy and resection of pretherapeutic endoanal ultrasonography–staged T3 and T4 rectal adenocarcinoma. METHODS: This retrospective review analyzed a series of 113 patients who underwent radiation therapy followed by surgery. All patients underwent an endoanal ultrasonography. Median follow-up was 75 months. RESULTS: Fifty-seven percent of patients were pT3 or T4. Thirty-six percent had involvement of lymph nodes. Five-year rates of survival, local recurrence–free survival, and disease-free survival were 79, 73, and 68 percent, respectively. Ten-year rates were 65, 63, and 62 percent, respectively. Median time to detection of local recurrence was 39 months. Eight of ten local recurrences occurred after two years of follow-up. Eight of ten patients with local recurrence had pretherapeutic endoanal ultrasonography–staged N+ tumors. CONCLUSION: These results appear to justify a follow-up program for patients with pretherapeutic endoanal ultrasonography–staged N+ tumor. However, a minimum of seven years of follow-up is needed to obtain an accurate assessment of results. [ABSTRACT FROM AUTHOR]

We describe the design, optimization and fabrication of side-illuminated p-i-n photodetectors, grown on InP substrate, suitable for surface hybrid integration in low-cost modules. The targeted functionalities of these photodetectors were a very high responsivity at 1.3- and 1.55-μm wavelengths and quasi-independent on the optical polarization, and had a high alignment tolerance. Moreover, in order to avoid any reliability problem, the principle of evanescent coupling was adopted. Two photodetectors were optimized, fabricated, and tested; the first was for classical cleaved fiber, and the second was for lensed fiber. Because the considered epitaxial structures were complicated to optimize, the method of the genetic algorithm was used, associated with a beam propagation method (BPM). The photodetectors are based on multimode diluted waveguides, which are promising structures in the field of optoelectronics and integrated optics. Starting from the presented comparisons between experimental and theoretical results, the interest of the design method is discussed and the complete performances of newly fabricated devices are presented. The aspect of the cutoff frequency is also considered [ABSTRACT FROM PUBLISHER]

A three-terminal edge-coupled InGaAs/InP phototransistor is reported. A dc photocurrent gain near 60 and an optical unity gain frequency of 40 GHz were measured. The mixing of a modulated optical signal and a microwave signal applied on the base terminal is presented. Optical and electrical modeling are used to analyze and improve the device performances. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 17: 408–412, 1998. [ABSTRACT FROM AUTHOR]

The ability of HSQ resist films to planarise active deep etched (1.5–2 µm) InP based structures with electrodes is demonstrated for the first time. Vertically etched III-V semiconductor devices require planarisation of the passivation material for metal interconnections and device integration. A new and quicker method is presented, for which it is not necessary to use mask opening on the top of the devices to define via patterns. A comparison between conventional silicon dioxide (SiO2) planarisation and the demonstrated HSQ method validates the interest of the latter. [ABSTRACT FROM AUTHOR]

This letter demonstrates an evanescently coupled p-i-n photodiode combined with a multimode diluted waveguide using a simple all 2-in InP processing that includes on-wafer mirrors etching and antireflection coating. A high responsivity of 0.81 A/W at 1.55 mum with less than 0.4-dB polarization dependence and a large -1-dB vertical alignment tolerance of 2.70 mum were achieved simultaneously with a bandwidth of 47 GHz. Stable operation for over 1000 h was obtained under bias stress and temperature at 200degC [ABSTRACT FROM PUBLISHER]

Experimentally carrier-induced optical index, propagation excess loss and carrier lifetime variations against injected current in n+- InP/i-InGaAsP/iInP/p+-InP heterostructures are investigated. The heterostructures have quaternary bandgap composition of λd 1.18 and 1.30 μm, and they were specially designed for 1.55 μm wavelength digital optical switch (DOS) applications. The Q130 based heterostructure shows the best potential for high-performance DOS. [ABSTRACT FROM AUTHOR]