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1.
Rev Gastroenterol Peru ; 44(1): 8-13, 2024.
Artigo em Espanhol | MEDLINE | ID: mdl-38734906

RESUMO

OBJECTIVE: Determine the sensitivity and specificity of the ESBP for diagnosis in patients with intermediate risk of choledocholithiasis, referred to the specialized surgical Gastroenterology center of Unión de Cirujanos SAS - Oncologists of the West Zentria group - Manizales - Colombia between March 01, 2020 to January 31, 2022. MATERIALS AND METHODS: Retrospective cross-sectional study in patients with intermediate risk for choledocholithiasis. The diagnostic performance of ESBP was calculated and confirmed with ERCP. Negative ESBPs were followed up by telephone. RESULTS: 752 cases with ESBP were analyzed, of which 43.2% (n=325) were positive and 56.8% (n=427) were negative. ERCP was performed in positive cases who accepted the procedure (n=317); 73.5% (n:233) were positive for choledocholithiasis, 25.8% (n=82) tumors and 0.6% (n=2) biliary roundworms. Patients with positive ESBP underwent ERCP. S= 98.3% (95% CI: 95.7-99.5) was obtained; E= 88.1% (95% CI: 79.2-94.1); PPV = 95.8% (95% CI: 92.4-98.0); NPV = 94.9% (95% CI: 87.4-98.7). The AUC of ESBP was 0.9319 (95% CI 0.8961-0.967). CONCLUSION: In patients with intermediate risk for choledocholithiasis, ESBP is a useful diagnostic option in the study of pancreatic pathologies, extrahepatic biliary tree, and the identification of biliary microlithiasis; Therefore, it also allows us to complement it with a therapeutic intervention such as ERCP in a single time.


Assuntos
Colangiopancreatografia Retrógrada Endoscópica , Coledocolitíase , Endossonografia , Sensibilidade e Especificidade , Humanos , Coledocolitíase/diagnóstico por imagem , Coledocolitíase/diagnóstico , Estudos Transversais , Estudos Retrospectivos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Endossonografia/métodos , Adulto , Idoso de 80 Anos ou mais
2.
Rev Gastroenterol Peru ; 44(2): 179-215, 2024.
Artigo em Espanhol | MEDLINE | ID: mdl-39019814

RESUMO

INTRODUCTION: Endoscopy plays a fundamental role in inflammatory bowel disease (IBD), and becomes essential in diagnosis, treatment monitoring, and detection and management of complications. MATERIALS AND METHODS: The Pan American Crohn's and Colitis Organization (PANCCO) and the Inter-American Society of Endoscopy (SIED) appointed 22 Latin American experts in IBD to develop a consensus study using the modified Delphi method, based on the best available evidence. A working group of 22 members from 9 countries identified 15 topics and formulated 98 statements, who participated in 2 rounds of voting. It was defined as agreement of ≥80% of experts for each statement. RESULTS: After the voting of all the statements, 8 statements were obtained that did not reach 80% consensus among the participants, so the questions were reconsidered in the Coordinating Committee of the consensus with the participation of the expert reviewers of these questions and 7 final statements were voted again by all the experts in a second round and 1 was eliminated with consensus. After two rounds of voting, the experts reached consensus with literature review with the best available evidence, the most important issues were developed with scientific evidence supporting each of the statements around the topic of endoscopy in IBD. CONCLUSIONS: Consensus statements were developed and based on the best available evidence about endoscopy in inflammatory bowel disease.


Assuntos
Técnica Delphi , Doenças Inflamatórias Intestinais , Humanos , Doenças Inflamatórias Intestinais/diagnóstico , Endoscopia Gastrointestinal/normas , Doença de Crohn/diagnóstico , América Latina , Sociedades Médicas , Consenso
3.
Sensors (Basel) ; 23(5)2023 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-36904937

RESUMO

In recent years, there has been a significant increase in the number of collisions between vehicles and vulnerable road users such as pedestrians, cyclists, road workers and more recently scooter riders, especially in urban streets. This work studies the feasibility of enhancing the detection of these users by means of CW radars because they have a low radar cross section. Since the speed of these users is usually low, they can be confused with clutter due to the presence of large objects. To this end, this paper proposes, for the first time, a method based on a spread spectrum radio communication between vulnerable road users and the automotive radar consisting of modulating a backscatter tag, placed on the user. In addition, it is compatible with low-cost radars that use different waveforms such as CW, FSK or FMCW, and hardware modifications are not required. The prototype that has been developed is based on a commercial monolithic microwave integrated circuit (MMIC) amplifier connected between two antennas, which is modulated by switching its bias. Experimental results with a scooter, under static and moving conditions, using a low-power Doppler radar at a 24 GHz band compatible with blind spot radars, are provided.

4.
Sensors (Basel) ; 22(19)2022 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-36236310

RESUMO

This work studies the feasibility of using a battery-less Near-Field Communication (NFC) potentiostat for the next generation of electrochemical point-of-care sensors. A design based on an NFC microchip, a microcontroller, and a custom potentiostat based on an operational amplifier is presented. A proof-of-concept prototype has been designed and used to quantify glucose concentration using commercial glucose test strips from chronoamperometry measurements. The device is harvested and the sensor is read using a mobile phone. The prototype uses an antenna loop covered with ferrite sheets to ensure stable operation of the electronics when the mobile phone is used as reader. The use of ferrite reduces the detuning caused by the proximity of the metal parts of the mobile phone. A comparison with a commercial glucometer device is provided. Results obtained using a commercial glucometer and those provided by the proposed potentiostat show an excellent agreement.


Assuntos
Fontes de Energia Elétrica , Sistemas Automatizados de Assistência Junto ao Leito , Compostos Férricos , Glucose
5.
Sensors (Basel) ; 22(19)2022 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-36236358

RESUMO

The present study exposes an economical and easy-to-use system to assess the heat transfer in building envelopes by determining the U-value. Nowadays these systems require long wires and a host to collect and process the data. In this work, a multi-point system for simultaneous heat flux measurement has been proposed. The aim is to reduce the long measurement time and the cost of thermal isolation evaluations in large buildings. The system proposed consists of a low-cost 3D-printed heat flux sensor integrated with a LoRa transceiver and two temperature sensors. The heat flux (HF) sensor was compared and calibrated with a commercial HF sensor from the Fluxteq brand.


Assuntos
Temperatura Alta , Coleta de Dados
6.
Sensors (Basel) ; 22(6)2022 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-35336318

RESUMO

This work studies the feasibility of using backscatter-modulated tags to introduce false information into a signal received by a frequency-modulated continuous-wave (FMCW) radar. A proof-of-concept spoofing device was designed in the 24 GHz ISM band. The spoofing device was based on an amplifier connected between two antennas, and modulation was carried out by switching the amplifier bias. The use of an amplifier allowed us to increase the level of spoofing signal compared with other modulated backscattering methods. The simulated and experimental results show that our method has the ability to generate a pair of false targets at different ranges and velocities depending on the modulation frequency of the chosen tag, since sidebands appear due to this modulation. Countermeasures to detect the spoofing attack based on changes in the slope of the frequency sweep between frames are also proposed.

7.
Rev Esp Enferm Dig ; 114(9): 522-528, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35000401

RESUMO

INTRODUCTION: the COVID-19 pandemic has seriously affected the world population, and has put health personnel in the spotlight as they are tasked with its management. Given their important role in the current health crisis, physicians have been heavily affected in terms of their professional practice, financial conditions and physical and mental health. The objective of this study was to determine the consequences of the COVID-19 pandemic for Colombian endoscopists and compare the effects on endoscopists from South America and from Spain. METHODS: in June 2021, an electronic survey was sent to 292 endoscopists from Colombia, South America and Spain to determine the impact of the pandemic on their professional practice, economic situation, physical and mental health, and training of the residents under their charge. Participants were recruited via convenience sampling. RESULTS: a reduction in the number of endoscopic procedures was reported by 69.9 % of the respondents, and 72.3 % of endoscopists in Colombia stated that their income had decreased. Regarding the doctor-patient relationship, 43.8 % of the respondents believed it had worsened. In addition, 70.9 % reported having experienced changes in their emotional state, especially those related to feeling sad or depressed, and 56.5 % reported that the pandemic had negatively affected the training of residents. Finally, 24.7 % of endoscopists tested positive for COVID-19, and 19.2 % reported the death of a family member due to COVID-19. CONCLUSION: the COVID-19 pandemic has had a negative impact on the professional practice, financial situation and physical and mental health of Ibero-American endoscopists. These problems must be identified in a timely manner to develop and implement strategies aimed to prevent their occurrence.


Assuntos
COVID-19 , Humanos , Pandemias/prevenção & controle , Relações Médico-Paciente , SARS-CoV-2 , Espanha/epidemiologia , Estados Unidos
8.
Sensors (Basel) ; 21(22)2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34833547

RESUMO

The COVID-19 pandemic has highlighted a large amount of challenges to address. To combat the spread of the virus, several safety measures, such as wearing face masks, have been taken. Temperature controls at the entrance of public places to prevent the entry of virus carriers have been shown to be inefficient and inaccurate. This paper presents a smart mask that allows to monitor body temperature and breathing rate. Body temperature is measured by a non-invasive dual-heat-flux system, consisting of four sensors separated from each other with an insulating material. Breathing rate is obtained from the temperature changes within the mask, measured with a thermistor located near the nose. The system communicates by means of long-range (LoRa) backscattering, leading to a reduction in average power consumption. It is designed to establish the relative location of the smart mask from the signal received at two LoRa receivers installed inside and outside an access door. Low-cost LoRa transceivers with WiFi capabilities are used in the prototype to collect information and upload it to a server. Accuracy in body temperature measurements is consistent with measurements made with a thermistor located in the armpit. The system allows checking the correct placement of the mask based on the recorded temperatures and the breathing rate measurements. Besides, episodes of cough can be detected by sudden changes in thermistor temperature.


Assuntos
COVID-19 , Máscaras , Atenção à Saúde , Temperatura Alta , Humanos , Pandemias , SARS-CoV-2
9.
Sensors (Basel) ; 21(11)2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-34073982

RESUMO

This work proposes the use of a modulated tag for direct communication between two vehicles using as a carrier the wave emitted by an FMCW radar installed in the vehicle for advanced driver assistance. The system allows for real-time signals detection and classification, such as stop signal, turn signals and emergency lights, adding redundancy to computer video sensors and without incorporating additional communication systems. A proof-of-concept tag has been designed at the microwave frequency of 24 GHz, consisting of an amplifier connected between receiving and transmitting antennas. The modulation is performed by switching the power supply of the amplifier. The tag is installed on the rear of the car and it answers when it is illuminated by the radar by modulating the backscattered field. The information is encoded in the modulation switching rate used. Simulated and experimental results are given showing the feasibility of the proposed solution.

10.
Sensors (Basel) ; 20(21)2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-33172140

RESUMO

This paper presents a method for low data rate transmission for devices implanted in the body using backscattered Long Range (LoRa) signals. The method uses an antenna loaded with a switch that changes between two load impedances at the rate of a modulating oscillator. Consequently, the LoRa signal transmitted by a LoRa node is reflected in the adjacent channels and can be detected with a LoRa gateway tuned to the shifted channels. A prototype developed to operate at Medical Implant Communication Service (MICS) and the Industrial Scientific and Medical (ISM) 433 MHz band is presented. The prototype uses a commercial ceramic antenna with a matched network tuned to the frequency band with high radiation efficiency. The effect of the coating material covering the antenna was studied. Simulated and experimental results using a phantom show that it is feasible to read data from deep implanted devices placed a few meters from the body because of the high sensitivity of commercial LoRa receivers.


Assuntos
Dispositivos Eletrônicos Vestíveis , Tecnologia sem Fio , Comunicação , Radiação Eletromagnética , Estudos de Viabilidade , Próteses e Implantes
11.
J Pathol ; 244(3): 334-345, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29243812

RESUMO

The oncogenic mechanisms and tumour biology underpinning clear cell sarcoma of the kidney (CCSK), the second commonest paediatric renal malignancy, are poorly understood and currently, therapy depends heavily on doxorubicin with cardiotoxic side-effects. Previously, we characterized the balanced t(10;17)(q22;p13) chromosomal translocation, identified at that time as the only recurrent genetic aberration in CCSK. This translocation results in an in-frame fusion of the genes YWHAE (encoding 14-3-3ϵ) and NUTM2, with a somatic incidence of 12%. Clinico-pathological features of that cohort suggested that this aberration might be associated with higher stage and grade disease. Since no primary CCSK cell line exists, we generated various stably transfected cell lines containing doxycycline-inducible HA-tagged YWHAE-NUTM2, in order to study the effect of expressing this transcript. 14-3-3ϵ-NUTM2-expressing cells exhibited significantly greater cell migration compared to isogenic controls. Gene and protein expression studies were indicative of dysregulated MAPK/PI3K-AKT signalling, and by blocking these pathways using neutralizing antibodies, the migratory advantage conferred by the transcript was abrogated. Importantly, CCSK tumour samples similarly show up-regulation/activation of these pathways. These results support the oncogenic role of 14-3-3ϵ-NUTM2 in CCSK and provide avenues for the exploration of novel therapeutic approaches. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.


Assuntos
Proteínas 14-3-3/metabolismo , Movimento Celular , Transformação Celular Neoplásica/metabolismo , Neoplasias Renais/enzimologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Sarcoma de Células Claras/enzimologia , Proteínas 14-3-3/genética , Animais , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Fusão Gênica , Células HEK293 , Humanos , Neoplasias Renais/genética , Neoplasias Renais/patologia , Camundongos , Proteínas Quinases Ativadas por Mitógeno/genética , Células NIH 3T3 , Proteínas de Fusão Oncogênica/genética , Fosfatidilinositol 3-Quinase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Sarcoma de Células Claras/genética , Sarcoma de Células Claras/patologia , Transdução de Sinais
12.
Sensors (Basel) ; 19(7)2019 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-30979009

RESUMO

This paper presents a color-based classification system for grading the ripeness of fruit using a battery-less Near Field Communication (NFC) tag. The tag consists of a color sensor connected to a low-power microcontroller that is connected to an NFC chip. The tag is powered by the energy harvested from the magnetic field generated by a commercial smartphone used as a reader. The raw RGB color data measured by the colorimeter is converted to HSV (hue, saturation, value) color space. The hue angle and saturation are used as features for classification. Different classification algorithms are compared for classifying the ripeness of different fruits in order to show the robustness of the system. The low cost of NFC chips means that tags with sensing capability can be manufactured economically. In addition, nowadays, most commercial smartphones have NFC capability and thus a specific reader is not necessary. The measurement of different samples obtained on different days is used to train the classification algorithms. The results of training the classifiers have been saved to the cloud. A mobile application has been developed for the prediction based on a table-based method, where the boundary decision is downloaded from a cloud service for each product. High accuracy, between 80 and 93%, is obtained depending on the kind of fruit and the algorithm used.


Assuntos
Técnicas Biossensoriais , Cor , Frutas/química , Tecnologia sem Fio , Algoritmos , Fontes de Energia Elétrica , Frutas/crescimento & desenvolvimento , Humanos , Dispositivo de Identificação por Radiofrequência/métodos
13.
Sensors (Basel) ; 18(11)2018 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-30400233

RESUMO

In this article, an overview of recent advances in the field of battery-less near-field communication (NFC) sensors is provided, along with a brief comparison of other short-range radio-frequency identification (RFID) technologies. After reviewing power transfer using NFC, recommendations are made for the practical design of NFC-based tags and NFC readers. A list of commercial NFC integrated circuits with energy-harvesting capabilities is also provided. Finally, a survey of the state of the art in NFC-based sensors is presented, which demonstrates that a wide range of sensors (both chemical and physical) can be used with this technology. Particular interest arose in wearable sensors and cold-chain traceability applications. The availability of low-cost devices and the incorporation of NFC readers into most current mobile phones make NFC technology key to the development of green Internet of Things (IoT) applications.

14.
Sensors (Basel) ; 18(11)2018 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-30373143

RESUMO

A passive harmonic tag for buried assets localization is presented for utility localization. The tag design is based on a dual-polarized patch antenna at Ultra High Frequency (UHF) band. One of its feeders is connected to a frequency doubler based on a Schottky diode that generates the second harmonic, which is transmitted using a linear-polarized patch tuned at this frequency. The power received at the other feeder of the dual-polarized antenna is harvested by an RF to DC converter based on a five-stage voltage multiplier whose energy is used to bias a low-power quartz oscillator that modulates the output of the doubler. The different parts of the system are presented, and the theoretical read range is estimated as a function of the soil composition and the water content. A low-cost reader based on a software defined radio is also presented. Finally, experiments with a prototype of the tag are performed for different soil conditions.

15.
J Pathol ; 238(5): 617-20, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27000436

RESUMO

Internal tandem duplication within the BCOR gene sequence that encodes the PUFD domain, important in the formation of the non-canonical or variant polycomb repressor complex 1 (v-PRC1), was very recently described in 100% of 20 clear cell sarcomas of kidney (CCSKs). None of those 20 cases bore the YWHAE-NUTM2 transcript, previously described by us in CCSK, and which constitutes the only other recurrent genetic aberration observed in CCSK, prompting consideration that these mutations might be mutually exclusive in CCSK. We analysed a cohort of 159 CCSKs and can now not only confirm that there is indeed mutual exclusivity of these BCOR and YWHAE mutations, but also show that a substantial proportion (in this series 11.8%) of CCSKs bear neither mutation when tested by these assays, raising the possibility of distinct aetiologies for subsets of CCSK. Clinical differences observed between the subsets support this notion. As CCSK may show poor chemo-responsiveness, and current treatment protocols mandate the use of doxorubicin with its associated side-effects, advances in understanding the disease biology with a view to more targeted and personalized treatment is a pressing need.


Assuntos
Biomarcadores Tumorais/genética , Duplicação Gênica , Fusão Gênica , Neoplasias Renais/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Repressoras/genética , Sarcoma de Células Claras/genética , Sequências de Repetição em Tandem , Adolescente , Sequência de Aminoácidos , Criança , Pré-Escolar , Análise Mutacional de DNA , Feminino , Predisposição Genética para Doença , Humanos , Lactente , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/patologia , Masculino , Dados de Sequência Molecular , Mutação , Fenótipo , Prognóstico , Sarcoma de Células Claras/tratamento farmacológico , Sarcoma de Células Claras/patologia
16.
Genes Chromosomes Cancer ; 55(2): 143-7, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26542179

RESUMO

Clear cell sarcoma of the kidney (CCSK) although uncommon, is the second most frequent renal malignancy of childhood. Until now, the sole recurrent genetic aberration identified in CCSKs is t(10;17)(q22;p13), which gives rise to a fusion transcript of YWHAE and NUTM2B/E. So far, the clinical relevance of this fusion transcript is unknown. The aim of this descriptive study was to determine the clinical phenotype of t(10;17)(q22;p13) positive CCSKs. Snap-frozen tissues, formalin-fixed paraffin-embedded tissues or RNA previously extracted from CCSK samples throughout European, North-American and Japanese study groups were screened by RT-PCR for the YWHAE-NUTM2B/E transcript. Clinical characteristics, tumor characteristics, and outcome of patients with and without the fusion transcript were studied. The cohort comprised 51 previously published cases to which were added 139 internationally collected CCSK samples. RNA from 57 of these additionally collected cases was of sufficient quality to be successfully screened for the YWHAE-NUTM2B/E transcript. In total, seven of the 108 cases harbored the fusion transcript. Patients with tumors containing the fusion transcript were relatively young (median age 10 months), had associated low median tumor volumes and stage I disease was not observed in these patients. Two of seven patients relapsed and one of seven patients died of disease. Ranges of values were not overtly different between patients with and without the fusion transcript; however, the number of fusion transcript positive cases turned out to be too small to permit reliable statistical analysis. The current study did not identify an explicit clinical phenotype of CCSK cases harboring the YWHAE-NUTM2B/E fusion transcript.


Assuntos
Proteínas 14-3-3/genética , Neoplasias Renais/patologia , Proteínas Repressoras/genética , Sarcoma de Células Claras/patologia , Adolescente , Criança , Pré-Escolar , Feminino , Predisposição Genética para Doença , Humanos , Lactente , Neoplasias Renais/genética , Masculino , Proteínas de Fusão Oncogênica/genética , Prognóstico , Sarcoma de Células Claras/genética , Análise de Sobrevida
17.
Arch Environ Contam Toxicol ; 69(2): 143-52, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25736902

RESUMO

In this work, 14 polycyclic aromatic hydrocarbons (PAHs) included in the United States Environmental Protection Agency pollutant priority list were analyzed in the surface water of the upper urbanized part of Almendares River, the most important water course in Havana, Cuba. Surface water from five sampling sites was collected at the end of dry season and analyzed by high-performance liquid chromatography-fluorescence detection method after solid phase extraction procedure. Total PAHs concentrations varied from 836 to 15 811 ng L(-1) with a geometric mean value of 2512 ng L(-1). PAH typology was dominated by low molecular-weight PAHs (2- to 3-ring components). Pollutant source appraisal was determined by diagnostic ratios method in five sampling sites. Factor analysis of normalized samples was used to concentration identified two factors as the main significant pollutant sources and to cluster similar sampling sites corresponding to petrogenic and combustion inputs, respectively. Ecological risks were considered. For animal aquatic life, acute toxicity values exceed the permissible values in the more-polluted sampling sites.


Assuntos
Monitoramento Ambiental , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Cuba , Rios/química , Extração em Fase Sólida
18.
Int J Mol Sci ; 16(7): 16593-621, 2015 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-26204834

RESUMO

Non-coding RNAs have received a lot of attention in recent years, with especial focus on microRNAs (miRNAs), so much so that in the just over two decades since the first miRNA, Lin4, was described, almost 40,000 publications about miRNAs have been generated. Less than 500 of these focus on sarcoma, and only a fraction of those on sarcomas of childhood specifically, with some of these representing observational studies and others containing functionally validated data. This is a group of cancers for which prognosis is often poor and therapeutic options limited, and it is especially in these areas that strides in understanding the role of non-coding RNAs and miRNAs in particular are to be welcomed. This review deals with the main forms of pediatric sarcoma, exploring what is known about the diagnostic and prognostic profiles of miRNAs in these tumours and where novel therapeutic options might present themselves for further exploration.


Assuntos
Biomarcadores Tumorais/genética , MicroRNAs/genética , Sarcoma/genética , Criança , Regulação Neoplásica da Expressão Gênica , Humanos , Sarcoma/diagnóstico , Sarcoma/metabolismo
19.
Sensors (Basel) ; 14(2): 2595-618, 2014 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-24514883

RESUMO

This paper focuses on the feasibility of tracking the chest wall movement of a human subject during respiration from the waveforms recorded using an impulse-radio (IR) ultra-wideband radar. The paper describes the signal processing to estimate sleep apnea detection and breathing rate. Some techniques to solve several problems in these types of measurements, such as the clutter suppression, body movement and body orientation detection are described. Clutter suppression is achieved using a moving averaging filter to dynamically estimate it. The artifacts caused by body movements are removed using a threshold method before analyzing the breathing signal. The motion is detected using the time delay that maximizes the received signal after a clutter removing algorithm is applied. The periods in which the standard deviations of the time delay exceed a threshold are considered macro-movements and they are neglected. The sleep apnea intervals are detected when the breathing signal is below a threshold. The breathing rate is determined from the robust spectrum estimation based on Lomb periodogram algorithm. On the other hand the breathing signal amplitude depends on the body orientation respect to the antennas, and this could be a problem. In this case, in order to maximize the signal-to-noise ratio, multiple sensors are proposed to ensure that the backscattered signal can be detected by at least one sensor, regardless of the direction the human subject is facing. The feasibility of the system is compared with signals recorded by a microphone.

20.
Biochem J ; 445(2): 213-8, 2012 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-22530721

RESUMO

Eukaryotic PFK (phosphofructokinase), a key regulatory enzyme in glycolysis, has homologous N- and C-terminal domains thought to result from duplication, fusion and divergence of an ancestral prokaryotic gene. It has been suggested that both the active site and the Fru-2,6-P2 (fructose 2,6-bisphosphate) allosteric site are formed by opposing N- and C-termini of subunits orientated antiparallel in a dimer. In contrast, we show in the present study that in fact the N-terminal halves form the active site, since expression of the N-terminal half of the enzymes from Dictyostelium discoideum and human muscle in PFK-deficient yeast restored growth on glucose. However, the N-terminus alone was not stable in vitro. The C-terminus is not catalytic, but is needed for stability of the enzyme, as is the connecting peptide that normally joins the two domains (here included in the N-terminus). Co-expression of homologous, but not heterologous, N- and C-termini yielded stable fully active enzymes in vitro with sizes and kinetic properties similar to those of the wild-type tetrameric enzymes. This indicates that the separately translated domains can fold sufficiently well to bind to each other, that such binding of complementary domains is stable and that the alignment is sufficiently accurate and tight as to preserve metabolite binding sites and allosteric interactions.


Assuntos
Dictyostelium/enzimologia , Músculos/enzimologia , Proteínas Mutantes Quiméricas/metabolismo , Fosfofrutoquinases/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Saccharomyces cerevisiae/enzimologia , Sítio Alostérico , Animais , Sítios de Ligação , Domínio Catalítico , Eucariotos , Frutosedifosfatos/metabolismo , Glicólise , Humanos , Immunoblotting , Proteínas Mutantes Quiméricas/genética , Fosfofrutoquinases/genética , Estrutura Terciária de Proteína , Proteínas Recombinantes de Fusão/genética , Saccharomyces cerevisiae/genética
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