Hybrid Manufactured Waveguide Resonators and Filters for mm-Wave Applications

Additive and hybrid manufactured waveguide resonators and bandpass filters for mm-wave applications are presented. A Ka band 3D printed waveguide resonator with inductive windows and 28 GHz 5G band hybrid manufactured waveguide resonator and bandpass filter are designed. Hybrid manufacturing combines 3D polymer printing and conventional metal processing technologies. In order to illustrate the accuracy of the design, a 3D printed waveguide transmission line and resonator with the resonant frequency of 33 GHz are fabricated and tested

Ultra Compact Inline E-Plane Waveguide Bandpass Filters Using Cross Coupling

This paper presents novel ultra-compact waveguide bandpass filters that exhibit pseudo elliptic responses with ability to place transmission zeros on both sides of the passband to form sharp roll offs. The filters contain E plane extracted pole sections cascaded with cross-coupled filtering blocks. Compactness is achieved by the use of evanescent mode sections and closer arranged resonators modified to shrink in size. The filters containing non-resonating nodes are designed by means of the generalized coupling coefficients (GCC) extraction procedure for the cross-coupled filtering blocks and extracted pole sections. We illustrate the performance of the proposed structures through the design examples of a third and a fourth order filters with center frequencies of 9.2 GHz and 10 GHz respectively. The sizes of the proposed structures suitable for fabricating using the low cost E plane waveguide technology are 38% smaller than ones of the E plane extracted pole filter of the same order

Low-Cost Hybrid Manufactured Waveguide Bandpass Filters with 3D Printed Insert Dielectric

In this paper, a new type of simple and inexpensive waveguide filter manufacturing that minimizes material consumption and has capabilities of high performance and rapid prototyping is presented. Filter inserts are fabricated by a combination of additive dielectric manufacturing and subtractive metal manufacturing, whereas standard waveguides are used as housings, utilizing best properties of each technology. Along with it, a suitable filter design using metal rectangular rings has been developed. Since the rings that act as positive reactance discontinuities in the passband are resonant at frequencies below it, it is possible to bring lower stopband transmission zeros near the passband to create sharp skirt. A resonator of such a filter and a third order bandpass filter sample have been designed at 11.13 GHz and 11.36 GHz centre frequencies respectively. In addition, smaller size rectangular rings in waveguide can realize upper stopband transmission zeros while acting as negative reactance discontinuities in the passband. This was utilized in fourth order bandpass filter at 11.36 GHz centre frequency with finite transmission zeros in both stopbands. All the filtering structures have been fabricated with 3D printer to extrude polylactic acid and circuit board plotter to mill copper sheet, and tested. Excellent measurement results that have been obtained validate the proposed design. Practical sides of achieving quality 3D printouts are analysed

Healthy aging through a healthy diet : never too old to eat healthy?!

Abstract Background: The world’s population is aging and with it the prevalence of chronic diseases, especially cardiovascular diseases and cancer, increases. A long lasting life is envisaged without the burden of disease. Therefore, current research focuses on risk factors, such as a healthy diet, which may decrease the occurrence of chronic diseases even at advanced age. Earlier studies, examining the role of a healthy diet in the elderly, applied different analysis strategies. In consequence, comparability across studies is limited and prevent an overall conclusion on the role of a healthy diet in elderly. Methods and subjects: Eleven prospective cohort studies among elderly people (N=396,391) from Europe and the United States, collaborating in the CHANCES consortium, were analysed. Most cohorts eligible for our analysis, assessed diet once at baseline. Therefore, we first assessed the stability of dietary patterns, derived with reduced rank regression (RRR), in the Zutphen Elderly Study. In the remainder of this thesis, healthy diets were defined based on the 2003 World Health Organization (WHO) “nutrient intake goals” and the 2007 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) food group recommendations. The recommendations were operationalized, using the Healthy Diet Indicator (HDI) and the WCRF/AICR diet score. The association between a healthy diet and risk of all-cause mortality and CVD mortality, was studied using the WHO recommendations, which aim at the prevention of chronic diseases in general. The cancer specific WCRF/AICR recommendations were applied to study the association between a healthy diet and cancer risk. Diet disease associations were assessed in each cohort separately, using Cox-proportional hazards regression. Cohort specific hazard ratios (HR) were pooled by random effects meta-analysis. Results: The results of the Zutphen Elderly Study showed that dietary patterns, derived by RRR, remained stable over a period of five years. In the CHANCES project a total of 84,978 person years were accumulated, during a median follow-up time ranging between 7 and 15 years across cohorts. An increase of 10 HDI points (range total score 0 to 70 points) was significantly associated with a decreased risk of all-cause mortality (HR: 0.90 and 95% confidence interval (CI): 0.87-0.93). The HR estimate was equivalent to a two year increase in life expectancy. We found a significant inverse association between an increase of 10 HDI points and CVD mortality for Southern European countries and the US (HR: 0.85, 95 % CI: 0.83-0.87), whereas no significant association was found for Northern and Central and Eastern Europe. An increase of 1 point for the WCRF/AICR diet score (range 0-4) was associated with a significantly 6% decreased risk in developing any type of cancer. Greatest risk reduction was found between a 1 point increase in WCRF/AICR diet score and colorectal cancer (HR: 0.84, 95% CI:0.80-0.89). Conclusion: Dietary indices based on globally defined dietary recommendations by WHO and WCRF/AICR were found to be associated with all-cause and CVD mortality and cancer risk in old age. Public health interventions targeted on the elderly should not focus on one definition of a “healthy diet” but rather a smart combination of available evidence, to optimally account for CVD as well as cancer specific outcomes. </p

Development of GaN transducer and on-chip concentrator for galvanic current sensing

Gallium nitride (GaN) magnetic high electron mobility transistors (MagHEMTs) with different gate lengths intended for integration with magnetic flux concentrator for galvanic isolation are presented. Detailed discussions on the physical mechanisms behind the sensitivity change at room temperature with respect to gate geometry are given. The relative sensitivity of dual-drain GaN MagHEMTs with a device length of L = 65 μm and a width of W = 20 μm is measured at the highest of S = 17.21%/T and the lowest of S = 7.69%/T at VGS= -2 V and VGS= 0 V, respectively. In addition, a novel spiral magnetic flux concentrator with the conversion factor of up to FC= 96 mT/A is designed for improving the performance of the optimized MagHEMTs in ICs. It is predicted that a spiral configuration is a necessity to enhance the conversion factor for a long MagHEMT

Eating dysfunction associated with oromandibular dystonia: clinical characteristics and treatment considerations

BACKGROUND: In oromandibular dystonia (OMD) abnormal repetitive contractions of masticatory, facial, and lingual muscles as well as the presence of orobuccolingual (OBL) dyskinesias may interfere with the appropriate performance of tasks such as chewing and swallowing leading to significant dysphagia and weight loss. We present here the clinical characteristics and treatment variables of a series of patients that developed an OMD-associated eating dysfunction. METHODS: We present a series of patients diagnosed and followed-up at the Movement Disorders Clinic of the Department of Neurology of University of Miami, Miller School of Medicine over a 10-year period. Patients were treated with botulinum toxin injections according to standard methods. RESULTS: Five out of 32 (15.6%) OMD patients experienced symptoms of eating dysfunction associated with OMD. Significant weight loss was reported in 3/5 patients (ranged for 13–15 lbs). Two patients regained the lost weight after treatment and one was lost to follow-up. Tetrabenazine in combination with other antidystonic medication and/or botulinum toxin injections provided substantial benefit to the patients with dysphagia caused by OMD. CONCLUSION: Dystonic eating dysfunction may occasionally complicate OMD leading to weight loss. Its adequate characterization at the time of history taking and clinical examination should be part of outcome measurements of the anti-dystonic treatment in clinical practice

Tissue temperature monitoring using thermoacoustic and photoacoustic techniques

Real-time temperature monitoring with high spatial resolution (~1 mm) and high temperature sensitivity (1 °C or better) is needed for the safe deposition of heat energy in surrounding healthy tissue and efficient destruction of tumor and abnormal cells during thermotherapy. A temperature sensing technique using thermoacoustic and photoacoustic measurements combined with a clinical Philips ultrasound imaging system (iU22) has been explored in this study. Using a tissue phantom, this noninvasive method has been demonstrated to have high temporal resolution and temperature sensitivity. Because both photoacoustic and thermoacoustic signal amplitudes depend on the temperature of the source object, the signal amplitudes can be used to monitor the temperature. The signal is proportional to the dimensionless Grueneisen parameter of the object, which in turn varies with the temperature of the object. A temperature sensitivity of 0.5 °C was obtained at a temporal resolution as short as 3.6 s with 50 signal averages

Temperature mapping using photoacoustic and thermoacoustic tomography

Photoacoustic (PA) and thermoacoustic (TA) effects are based on the generation of acoustic waves after tissues absorb electromagnetic energy. The amplitude of the acoustic signal is related to the temperature of the absorbing target tissue. A combined photoacoustic and thermoacoustic imaging system built around a modified commercial ultrasound scanner was used to obtain an image of the target's temperature, using reconstructed photoacoustic or thermoacoustic images. To demonstrate these techniques, we used photoacoustic imaging to monitor the temperature changes of methylene blue solution buried at a depth of 1.5 cm in chicken breast tissue from 12 to 42 °C. We also used thermoacoustic imaging to monitor the temperature changes of porcine muscle embedded in 2 cm porcine fat from 14 to 28 °C. The results demonstrate that these techniques can provide noninvasive real-time temperature monitoring of embedded objects and tissue

Performance characterization of an integrated ultrasound, photoacoustic, and thermoacoustic imaging system

We developed a novel trimodality system for human breast imaging by integrating photoacoustic (PA) and thermoacoustic (TA) imaging techniques into a modified commercial ultrasound scanner. Because light was delivered with an optical assembly placed within the microwave antenna, no mechanical switching between the microwave and laser sources was needed. Laser and microwave excitation pulses were interleaved to enable PA and TA data acquisition in parallel at a rate of 10 frames per second. A tube (7 mm inner diameter) filled with oxygenated bovine blood or 30 mM methylene blue dye was successfully detected in PA images in chicken breast tissue at depths of 6.6 and 8.4 cm, respectively, for the first time. The SNRs at these depths reached ∼24 and ∼15  dB, respectively, by averaging 200 signal acquisitions. Similarly, a tube (13 mm inner diameter) filled with saline solution (0.9%) at a depth of 4.4 cm in porcine fat tissue was successfully detected in TA images. The PA axial, lateral, and elevational resolutions were 640 μm, 720 μm, and 3.5 mm, respectively, suitable for breast cancer imaging. A PA noise-equivalent sensitivity to methylene blue solution of 260 nM was achieved in chicken tissue at a depth of 3.4 cm

Treating patients across European Union borders : an international survey in light of the coronavirus disease-19 pandemic

BACKGROUND In light of the coronavirus disease-2019 (COVID-19) pandemic, how resources are managed and the critically ill are allocated must be reviewed. Although ethical recommendations have been published, strategies for dealing with overcapacity of critical care resources have so far not been addressed. OBJECTIVES Assess expert opinion for allocation preferences regarding the growing imbalance between supply and demand for medical resources. DESIGN A 10-item questionnaire was developed and sent to the most prominent members of the European Society of Anaesthesiology and Intensive Care (ESAIC). SETTING Survey via a web-based platform. PATIENTS Respondents were members of the National Anaesthesiologists Societies Committee and Council Members of the ESAIC; 74 of 80 (92.5%), responded to the survey. MEASUREMENTS AND MAIN RESULTS Responses were analysed thematically. The majority of respondents (83.8%), indicated that resources for COVID-19 were available at the time of the survey. Of the representatives of the ESAIC governing bodies, 58.9% favoured an allocation of excess critical care capacity: 69% wished to make them available to supraregional patients, whereas 30.9% preferred to keep the resources available for the local population. Regarding the type of distribution of resources, 35.3% preferred to make critical care available, 32.4% favoured the allocation of medical equipment and 32.4% wished to support both options. The majority (59.5%) supported the implementation of a central European institution to manage such resource allocation. CONCLUSION Experts in critical care support the allocation of resources from centres with overcapacity. The results indicate the need for centrally administered allocation mechanisms that are not based on ethically disputable triage systems. It seems, therefore, that there is wide acceptance and solidarity among the European anaesthesiological community that local medical and human pressure should be relieved during a pandemic by implementing national and international re-allocation strategies among healthcare providers and healthcare systems