This work presents an analytic model to derive the scan impedance of planar infinite phased arrays of dipoles at a dielectric interface when only the (0, 0) Floquet mode propagates. The proposed ...model builds on the boundary conditions met by the fundamental Floquet mode at the interface to provide a novel derivation of the equivalent circuit for the scan impedance. The analysis is also extended to include the effect of a sufficiently thick grounded substrate that does not affect the elements' current distribution and does not interact with the evanescent fields. Next, formulas for the ratio of intensity radiated toward each half-space for an interfacial array are provided. In a consecutive step, an asymptotic approximation is derived for the current distribution in arrays of arbitrary loaded dipoles, and the reactance of a dipole in the array environment is related to the inductance of a grid of wires. This model constitutes a useful tool to clearly identify the role of the different array variables (dipole dimensions, relative permittivity of the substrate, periodicity, end load, and scan angle in the principal planes) on the scan impedance by simple expressions and equivalent circuits. The model predictions are in good agreement with full-wave simulations and with previously published works.
We present a photonically-excited antenna array at E-band for scanning by beam switching in wireless links. First, we discuss the proposed technique applied to photonic-enabled (sub)millimeter-wave ...transmitters. Next, we present our implementation; it consists of two sub-arrays of stacked patches as primary feeds of a Polytetrafluoroethylene (PTFE) lens, with one photodiode feeding each sub-array. To validate the assembly, the return loss and radiation patterns have been measured for one of the sub-arrays excited with a coplanar probe. In turn, the lens illuminated by one of the sub-arrays yields a directivity of 27 dBi. The radiation patterns measured for the transmitter module (including the lens) are in very good agreement with full-wave simulations, and they show that excitation of one of either sub-arrays allows beam switching between <inline-formula><tex-math notation="LaTeX">\pm 2.7^\circ</tex-math></inline-formula> with a beam crossover at <inline-formula><tex-math notation="LaTeX">-3\, \mathrm{dB}</tex-math></inline-formula>. Finally, we have tested the transmitter in a 0.6 m wireless link. Depending on the position of the detector and on which sub-array is excited, we have accomplished 5 Gbps transmission for on-off-keying modulation and direct detection (BER <inline-formula><tex-math notation="LaTeX">=10^{-11}</tex-math></inline-formula>). The system constitutes an initial proof of photonic-assisted beam switching for mm-wave transmitters enabling broadband operation with a directive and switchable beam.
Objective
To offer a practical guide for the presurgical and anesthetic management of pheochromocytomas and sympathetic paragangliomas (PGLs).
Methods
This protocol was based on a comprehensive ...review of the literature and on our own multidisciplinary team’s experience from managing pheochromocytoma and sympathetic PGLs at a referral center.
Results
Patients with pheochromocytomas and sympathetic paragangliomas (PGLs) may develop potentially life-threatening complications, especially during surgical procedures. A complete biochemical, radiological, genetic, and cardiological assessment is recommended in the preoperative stage as it provides an evaluation of the risk of surgical complications and malignancy, allowing individualization of the presurgical treatment. Treatment with α-blockade and proper volume expansion in the preoperative stage significantly reduces the perioperative morbidity. During surgery, the anesthesiologist should look for a deep anesthetic level that inhibits the cardiovascular effects of catecholamines to minimize the risk of intraoperative complications.
Conclusions
An optimal presurgical evaluation of pheochromocytomas/ sympathetic PGL requires a multidisciplinary approach, including a complete hormonal, radiological, cardiac, genetic, and functioning evaluation in most cases. A proper preoperative evaluation in combination with strict blood pressure and heart rate control, and blood volume status optimization, will significantly reduce the risk of intraoperative and perioperative complications. In those patients who unfortunately develop intraoperative complications, the role of the anesthesiologist is essential since the selection of the appropriate management has a direct impact on morbimortality reduction.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This manuscript reports the first leaky-wave antenna (LWA) array excited by a photomixer as well as its potential application for alignment in wireless links. The designed array is manufactured in ...printed circuit board (PCB) technology, works at the E-band (from 75 to 85 GHz), and provides a directive beam of about 18 dBi with a frequency scanning span of 22°. The antenna element consists of a microstrip line periodically loaded with stubs, and it has been designed employing a hybrid approach combining full-wave simulations and transmission line theory. This approach enables the optimization of the periods when the open-stopband of the LWA is mitigated or removed at the frequency of broadside emission. The proposed antenna was first tested using a ground signal ground (GSG) probe; the measured return loss and radiation patterns of the fabricated prototype were in good agreement with full-wave simulations. Then, the LWA array was integrated with the photomixer chip using conductive epoxy threads. Measurements of the radiated power yielded a maximum of 120 µW at 80.5 GHz for a 9.8 mA photocurrent. Finally, the antenna was used in a 25 cm wireless link, obtaining a 2.15 Gbps error-free data rate.
To describe our current protocol for surgical and postsurgical management of abdominal paragangliomas (PGLs) and pheochromocytomas, with a special focus on multidisciplinary management in centres ...with experience.
The physicians involved in the management of patients with abdominal PGLs and pheochromocytomas of our hospital reviewed systematically current knowledge on the surgical management of abdominal PGLs and pheochromocytomas.
Currently, surgery is considered the treatment of choice for abdominal PGLs and pheochromocytomas. The choice of surgical approach is determined based on the location of the lesion, size, patient́s body habitus and the likelihood of malignancy. Laparoscopic surgery is usually considered the gold standard approach for pheochromocytomas, but open access should be considered in invasive and/or potentially malignant tumours >8–10 cm and for abdominal PGLs. Postsurgical management of pheochromocytomas and PGLs includes close hemodynamic monitoring and treatment of postsurgical complications, the pathological study of the surgical specimen, reassessment of hormonal and/or radiological status and planning of follow-up based on the risk of recurrence and malignancy.
Surgery represents the treatment of choice of most abdominal PGLs and pheochromocytomas. Optimal postsurgical evaluation, including hemodynamic, pathological, hormonal, and radiological evaluation, should be performed by a multidisciplinary team specializing in PGL/pheochromocytoma management.
Describir nuestro protocolo actual para el manejo quirúrgico y posquirúrgico de los paragangliomas abdominales (PGL) y los feocromocitomas, con especial atención en el manejo multidisciplinar en centros con experiencia.
Los facultativos implicados en el tratamiento de pacientes con PGL abdominales y feocromocitomas de nuestro hospital revisaron sistemáticamente la bibliografía actual sobre el tratamiento quirúrgico de los PGL abdominales y feocromocitomas.
La cirugía se considera el tratamiento de primera elección para los PGL abdominales y feocromocitomas. La decisión sobre el abordaje quirúrgico se basa en la localización y el tamaño de la lesión, la constitución corporal del paciente y la probabilidad estimada de malignidad. La cirugía laparoscópica suele considerarse el método de referencia para los feocromocitomas, pero el abordaje abierto debe considerarse en los tumores invasivos y/o potencialmente malignos de más de 8–10 cm y en los PGL abdominales. El tratamiento posquirúrgico de los feocromocitomas y los PGL incluye una monitorización hemodinámica estrecha y el tratamiento de las complicaciones posoperatorias, el estudio patológico de la muestra quirúrgica, la reevaluación del estado hormonal y/o radiológico y la planificación del seguimiento en función del riesgo de recurrencia y de malignidad.
La cirugía representa el tratamiento de elección de la mayoría de los PGL abdominales y feocromocitomas. La evaluación posoperatoria óptima, que incluye la evaluación hemodinámica, patológica, hormonal y radiológica, debe ser realizada por un equipo multidisciplinar especializado en el tratamiento de PGL/feocromocitomas.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This manuscript reports the first leaky-wave antenna (LWA) array excited by a photomixer as well as its potential application for alignment in wireless links. The designed array is manufactured in ...printed circuit board (PCB) technology, works at the E-band (from 75 to 85 GHz), and provides a directive beam of about 18 dBi with a frequency scanning span of 22degrees. The antenna element consists of a microstrip line periodically loaded with stubs, and it has been designed employing a hybrid approach combining full-wave simulations and transmission line theory. This approach enables the optimization of the periods when the open-stopband of the LWA is mitigated or removed at the frequency of broadside emission. The proposed antenna was first tested using a ground signal ground (GSG) probe; the measured return loss and radiation patterns of the fabricated prototype were in good agreement with full-wave simulations. Then, the LWA array was integrated with the photomixer chip using conductive epoxy threads. Measurements of the radiated power yielded a maximum of 120 qW at 80.5 GHz for a 9.8 mA photocurrent. Finally, the antenna was used in a 25 cm wireless link, obtaining a 2.15 Gbps error-free data rate. Keywords: photomixer; photonic antenna; PCB antenna; E-band; beam scanning; beam steering; probe de-embedding; leaky-wave antenna; epoxy bonding; RF choke
We present a photonic transmitter at E-band for beam switching in mm-wave wireless links. First, we discuss the trade-offs between beam switching and beam steering with arrays of photonic ...transmitters. Then, the designed transmitter is presented; it includes two 2×2 sub-arrays of stacked patches fed independently by two photodiodes. The transmitter is placed at the focal plane of a PTFE lens to increase the overall gain. Excitation of either sub-array allows 1D beam witching between ±2.7º for accurate beam alignment or reconfigurable links.
‘Differential placebo effects’ is the concept that different types of placebos (e.g. inert pill versus sham device) may yield different magnitudes of placebo effects. This issue has been pushed into ...the spotlight by recent clinical trials of new technologies reporting unexpectedly large placebo effects from sham devices/procedures needed to maintain blinding integrity. In this Neurology Grand Rounds, we use transcranial magnetic stimulation as a model to explore the principles and implications of differential placebo effects. We highlight emerging research on the neurobiology of placebo effects and analyze fundamental questions of measuring efficacy in contemporary medicine.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Biomarkers have transformed modern medicine but remain largely elusive in psychiatry, partly because there is a weak correspondence between diagnostic labels and their neurobiological substrates. ...Like other neuropsychiatric disorders, depression is not a unitary disease, but rather a heterogeneous syndrome that encompasses varied, co-occurring symptoms and divergent responses to treatment. By using functional magnetic resonance imaging (fMRI) in a large multisite sample (n = 1,188), we show here that patients with depression can be subdivided into four neurophysiological subtypes ('biotypes') defined by distinct patterns of dysfunctional connectivity in limbic and frontostriatal networks. Clustering patients on this basis enabled the development of diagnostic classifiers (biomarkers) with high (82-93%) sensitivity and specificity for depression subtypes in multisite validation (n = 711) and out-of-sample replication (n = 477) data sets. These biotypes cannot be differentiated solely on the basis of clinical features, but they are associated with differing clinical-symptom profiles. They also predict responsiveness to transcranial magnetic stimulation therapy (n = 154). Our results define novel subtypes of depression that transcend current diagnostic boundaries and may be useful for identifying the individuals who are most likely to benefit from targeted neurostimulation therapies.
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IJS, NUK, SBMB, UL, UM, UPUK
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