Outphasing transmitters have been explored to study the trade-off between linearity and efficiency. The outphasing technique enhances efficiency by operating two amplifiers at lower output ...amplitudes, using two constant envelope signals. Their major drawback is the inherent sensitivity to gain and phase imbalances between the two amplifier branches. Another important issue is related to the degradation of efficiency, especially in isolated combiners. This paper presents a Statistical Markov-Chain Mode-Multiplexing (MM) transmitter which combines features of the MM and Reverse MM-LINC. Commercial analog devices and a digital platform for signal processing purposes are used to test the performance with an orthogonal frequency multiplexing modulation (OFDM), which is one of the most used modulation schemes in wireless communication systems.
Objectives Hyperinsulinemic hypoglucemia (HH) is characterized by a dysregulation of insulin secretion from pancreatic β cells. Congenital hyperinsulinism has been associated with specific genes in ...monogenic forms and also with other diseases with a yet unknown genetic cause. In 2017, Rubio Cabezas et al. described the association of HH and autosomal recessive polycystic kidney disease (ARPKD) with a promoter mutation in the PMM2 gene. They found that all the patients carried a promoter mutation (c-167G>T) in PMM2, either homozygous or in trans with a second PMM2 coding mutation. Methods We performed the study of the PMM2 gene in six patients from four unrelated families, previously diagnosed with ARPKD and HH. Results All these patients had in common the heterozygous variant c-167G>T in the promoter region for PMM2. Additionally, each patient carried a compound heterozygote for a second missense mutation in this gene (p.Arg141His, p.Asp148Asn or p.Phe157Ser), previously reported as pathogenic for congenital disorder of glycosylation type Ia, with an autosomal recessive inheritance pattern. Unlike the previous published article, two of our patients showed altered type 1 pattern and one of them with rectal bleeding that could be a sign of PMM2-congenital disorders of glycosylation. Conclusion We propose the study of this gene when carrying out the diagnosis of patients with HH, especially in the neonatal period and when a recessive polycystic kidney disease without alterations in PKDH1 is diagnosed.
Error vector magnitude (EVM) and out-of-band emissions are key metrics for evaluating in-band and out-band distortions introduced by all potential non-idealities in the transmitters of wireless ...systems. As EVM is a measure of the quality of the modulated signal/symbols, LTE/LTE-A and 5G systems specify mandatory EVM requirements in transmission for each modulation scheme. This paper analyzes the influence of the mandatory satisfaction of EVM requirements on the design of radio resource management strategies (RRM) (link adaptation, inter-cell interference coordination), specifically in the downlink (DL). EVM depends on the non-idealities of the transmitter implementations, on the allocated power variations between the subcarriers and on the selected modulations. In the DL of LTE, link adaptation is usually executed by adaptive modulation and coding (AMC) instead of power control, but some flexibility in power allocation remains being used. LTE specifies some limits in the power dynamic ranges depending on the allocated modulation, which ensures the satisfaction of EVM requirements. However, the required recommendations concerning the allowed power dynamic range when inter-cell interference coordination (ICIC) and enhanced ICIC (eICIC) mechanisms (through power coordination) are out of specification, even though the EVM performance should be known to obtain the maximum benefit of these strategies. We perform an experimental characterization of the EVM in the DL under real and widely known ICIC implementation schemes. These studies demonstrate that an accurate analysis of EVM is required. It allows a better adjustment of the design parameters of these strategies, and also allows the redefinition of the main criteria to be considered in the implementation of the scheduler/link adaptation concerning the allocable modulation coding scheme (MCS) in each resource block.
The emergence of SARS-CoV-2 in 2019 and its rapid spread throughout the world has caused the largest pandemic of our modern era. The zoonotic origin of this pathogen highlights the importance of the ...One Health concept and the need for a coordinated response to this kind of threats. Since its emergence, the virus has caused >7 million deaths worldwide. However, the animal source for human outbreaks remains unknown. The ability of the virus to jump between hosts is facilitated by the presence of the virus receptor, the highly conserved angiotensin-converting enzyme 2 (ACE2), found in various mammals. Positivity for SARS-CoV-2 has been reported in various species, including domestic animals and livestock, but their potential role in bridging viral transmission to humans is still unknown. Additionally, the virus has evolved over the pandemic, resulting in variants with different impacts on human health. Therefore, suitable animal models are crucial to evaluate the susceptibility of different mammalian species to this pathogen and the adaptability of different variants. In this work, we established a transgenic mouse model that expresses the feline ACE2 protein receptor (cACE2) under the human cytokeratin 18 (K18) gene promoter's control, enabling high expression in epithelial cells, which the virus targets. Using this model, we assessed the susceptibility, pathogenicity, and transmission of SARS-CoV-2 variants. Our results show that the sole expression of the cACE2 receptor in these mice makes them susceptible to SARS-CoV-2 variants from the initial pandemic wave but does not enhance susceptibility to omicron variants. Furthermore, we demonstrated efficient contact transmission of SARS-CoV-2 between transgenic mice that express either the feline or the human ACE2 receptor.
Background:
Cervical pain is a problem with a high prevalence of ~13% of the population, and is more common in women (16.5%). The most affected age group is 65–74 years. Our aim was to assess the ...effectiveness of self-applied acupressure for decreasing benign-origin cervical pain, under the supervision of a health professional and in combination with usual treatment, as well as to examine its impact on the patient’s self-perceived health condition and their opinion of the technique.
Methods:
Pragmatic, multicenter, controlled clinical trial randomized by healthcare center. A total of 160 patients with benign-origin cervical pain between 18 and 65 years of age who attended primary care were included from 12 healthcare centers in the autonomous community of Madrid by consecutive sampling, and randomly assigned to a control or intervention group. The main outcome variable was pain intensity measured on a visual analogue scale (VAS) and secondary variables were self-perceived quality of life (EuroQol-5D utility index) and functional ability (neck disability index). An explanative model of generalized estimating equations was built taking into account the lack of independence among observations. The analysis was performed over 6 months.
Results:
In total, 150 patients completed the study. Mean age was 45 years (SD: 10.7), 86.7% were women, 86.2% were currently employed, and 57.9% did not perform any physical exercise. Average days experiencing pain was 32.9 (SD: 2.8) and 80% were undergoing previous pharmacological treatment. The quality of life utility index after 3 months was 1.6 points (95% CI: 0.54–2.71) higher in the intervention group. The pain score on the VAS was 0.16 points (95% CI: 0.80–0.48) lower in the intervention group. The health professional explained 10.4% of the reduction in pain observed on the VAS throughout the medical visits.
Conclusion:
Acupressure applied in addition to usual practice appeared to improve cervical pain in the long term. The effectiveness of this technique was partially explained by the health professional that trained the participants on technique application.
Trial registration number::
NCT01855893
Reconfigurable Matching Networks (RMN) have found a wide range of applications, such as antenna impedance matching (Antenna Tuning Units -ATU-), the design of reconfigurable power amplifiers, ...applications in Magnetic Resonance Imaging (MRI), adjustable low noise amplifier design, etc. In this paper, we propose the experimental design and verification of a reconfigurable impedance synthesis network that can simultaneously work in three different bands and is completely independent so that the impedance variations in a frequency band are approximately transparent to the rest. The variable elements used in this paper are varactors. To verify its operation, it is applied to a process of matching a laser modulator in three different frequency bands for C-RAN (Cloud Radio Access Networks) applications. Experimental results demonstrate, as expected, that losses may depend on the state in which they are driven. Consequently, a state that can guarantee a good match could also imply greater losses, leading to a certain trade-off. The application of genetic algorithms in this context points out that it may be convenient to optimize the insertion losses of the complete chain instead of the return losses.
This article proposes the linearization of an intensity modulation/direct detection radio-over-fiber (RoF) link with feedback loop. The goal is to carry out the predistortion process in a real ...scenario, in which the output signals are a few kilometers far from the baseband unit (BBU). First, the feedback loop is considered ideal, so the output signals are captured at the remote radio head side. Then, the feedback loop is taken into account, and both the input and output signals are captured at the BBU side. Applying optimization algorithms, such as Fibonacci, Golden, or Powell, it is possible to seek the optimal attenuation value within only a few iterations, which minimizes the distortion of the feedback loop. Experiments are carried out in a RoF system with 10 and 25 km length fiber within the long-term evolution (LTE) standard. Measured results show how with a proper choice of the attenuation it is possible to reach analogous results regarding to an ideal feedback loop in terms of adjacent channel power ratio, the output signal power and error vector magnitude.
DVB-H (digital video broadcasting for handheld) is one of the technology standards for the transmission of digital TV to handheld receivers such as mobile phones or PDAs. Antenna design for DVB-H ...terminals is challenging due to the size limitation and as a result, the antenna presents large mismatches. To address this issue, we propose the use of a reconfigurable tuning network to reduce the mismatch (or the antenna size for a given mismatch) between the antenna and the RF front-end in a DVB-H terminal. This technique offers some advantages over other proposed alternatives and improves the antenna realized gain, as well as the overall efficiency of the DVB-H receiver.
We propose a new 3-D conformal spiral antenna that is based on the standard equiangular spiral geometry for automotive applications. The impact of its integration when it is placed inside a wing ...mirror is investigated. The antenna is miniaturized using meandered surface techniques to increase the electrical length and improve its performance. Scattering parameters are numerically estimated with the aid of the commercial code HFSS (finite element method). Experimental measurements show a wide frequency bandwidth that is suitable for several car communication systems.
This brief presents the application of a reconfigurable matching network (RMN) to improve the efficiency of an RF power amplifier (PA) using dynamic load modulation techniques under different antenna ...mismatch conditions. By changing the RMN state, a near-optimal output impedance is presented to the PA, achieving high efficiency for all input-driven levels. Simulations show efficiency enhancement, while nonlinear distortion can be mitigated using digital predistortion. It will be also shown that under severe mismatch conditions, using an RMN, significant efficiency and linearity improvements can be achieved.
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