BACKGROUND: Monitoring and control of PM(2.5) are being recognized as key to address health issues attributed to PM(2.5). Availability of low-cost PM(2.5) sensors made it possible to introduce a number of portable PM(2.5) monitors based on light scattering to the consumer market at an affordable price. Accuracy of light scattering–based PM(2.5) monitors significantly depends on the method of calibration. Static calibration curve is used as the most popular calibration method for low-cost PM(2.5) sensors particularly because of ease of application. Drawback in this approach is, however, the lack of accuracy.METHODS: This study discussed the calibration of a low-cost PM(2.5)-monitoring device (PMD) to improve the accuracy and reliability for practical use. The proposed method is based on construction of the PM(2.5) sensor network using Message Queuing Telemetry Transport (MQTT) protocol and web query of reference measurement data available at government-authorized PM monitoring station (GAMS) in the republic of Korea. Four machine learning (ML) algorithms such as support vector machine, k-nearest neighbors, random forest, and extreme gradient boosting were used as regression models to calibrate the PMD measurements of PM(2.5). Performance of each ML algorithm was evaluated using stratified K-fold cross-validation, and a linear regression model was used as a reference.RESULTS: Based on the performance of ML algorithms used, regression of the output of the PMD to PM(2.5) concentrations data available from the GAMS through web query was effective. The extreme gradient boosting algorithm showed the best performance with a mean coefficient of determination (R²) of 0.78 and standard error of 5.0 μg/m³, corresponding to 8% increase in R² and 12% decrease in root mean square error in comparison with the linear regression model. Minimum 100 hours of calibration period was found required to calibrate the PMD to its full capacity. Calibration method proposed poses a limitation on the location of the PMD being in the vicinity of the GAMS. As the number of the PMD participating in the sensor network increases, however, calibrated PMDs can be used as reference devices to nearby PMDs that require calibration, forming a calibration chain through MQTT protocol.CONCLUSIONS: Calibration of a low-cost PMD, which is based on construction of PM(2.5) sensor network using MQTT protocol and web query of reference measurement data available at a GAMS, significantly improves the accuracy and reliability of a PMD, thereby making practical use of the low-cost PMD possible.
Calibration ; Forests ; Linear Models ; Machine Learning ; Methods ; Particulate Matter ; Republic of Korea ; Support Vector Machine ; Telemetry

PURPOSE: The purpose of this study was to measure energy expenditure (EE) the metabolic equivalents (METs) of 13 common physical activities by using a portable telemetry gas exchange system (K4b2) and to assess the accuracy of the accelerometer (Actigraph GT3X+) by gender in Korean adults. METHODS: A total of 109 adults (54 males, 55 females) with normal BMI (body mass index) participated in this study. EE and METs of 13 selected activities were simultaneously measured by the K4b2 portable indirect calorimeter and predicted by the GT3X+ Actigraph accelerometer. The accuracy of the accelerometer was assessed by comparing the predicted with the measured EE and METs. RESULTS: EE (kcal/kg/hr) and METs of treadmill walking (3.2 km/h, 4.8 km/h and 5.6 km/h) and running (6.4 km/h) were significantly higher in female than in male participants (p < 0.05). On the other hand, the accelerometer significantly underestimated the EE and METs for all activities except descending stairs, moderate walking, and fast walking in males as well as descending stairs in females. Low intensity activities had the highest rate of accurate classifications (88.3% in males and 91.3% females), whereas vigorous intensity activities had the lowest rate of accurate classifications (43.6% in males and 27.7% in females). Across all activities, the rate of accurate classification was significantly higher in males than in females (75.2% and 58.3% respectively, p < 0.01). Error between the accelerometer and K4b2 was smaller in males than in females, and EE and METs were more accurately estimated during treadmill activities than other activities in both males and females. CONCLUSION: The accelerometer underestimated EE and METs across various activities in Korean adults. In addition, there appears to be a gender difference in the rate of accurate accelerometer classification of activities according to intensity. Our results indicate the need to develop new accelerometer equations for this population, and gender differences should be considered.
Adult* ; Calorimetry, Indirect ; Classification ; Energy Metabolism* ; Female ; Hand ; Humans ; Male ; Metabolic Equivalent ; Motor Activity* ; Running ; Telemetry ; Walking

Less traumatic electrode insertion along the basal turn of cochlea is essential to cochlear implantation. However, immoderate attempts to insert the electrode beyond the point of resistance can result in electrode kinking within the basal turn of cochlea. Electrode kinking tends to occur 1) in the use of contour or hugging type of electrode, 2) in the cochlear ossification or fibrosis, and 3) in wrong angle insertion in the approach of round window membrane or cochleostomy near the round window. Intra-operative radiologic evaluation and intra-operative measurement of the neural response telemetry or auditory nerve response telemetry during cochlear implantation is essential to check the status and proper insertion of electrode. Recently, we experienced two cases of electrode kinking in cochlear implantation and discovered that both patients showed abnormal impedances and crumpled electrode in X-ray. Based on these cases, we suggest routine impedance and radiologic measurement during the cochlear implantation.
Cochlea ; Cochlear Implantation* ; Cochlear Implants* ; Cochlear Nerve ; Electric Impedance ; Electrodes* ; Fibrosis ; Humans ; Membranes ; Telemetry

BACKGROUND: Patients with acute ischemic stroke are susceptible  to  cardiac  arrhythmias  however,fatal arrhythmias  are  rare  in  the  absence  of  cardiac  disease.Cardiac arrhythmias can develop in lesions at the right side of the brain specifically the insular,frontal and parietal area.Data that show the direct relationship of ischemic stroke and arrhythmia are scarce but they are indirectly attributed to an imbalance in the autonomic nervous system.This paper aims to present a rare case of an association between a fatal arrhythmia and right thalamic infarct.  
CASE: Presenting a case of a 39-year-old admitted as a survivor of sudden cardiac death from ventricular fibrillation.She presented with a history of left sided weakness a week prior but no work-up was done. Baseline serum electrolytes and  cardiac markers were all normal.Electrocardiogram (ECG) post-cardioversion showed sinus tachycardia.Echocardiogram   and cardiac computed tomography (CT) angiography were normal.  Magnetic resonance imaging (MRI) and angiography (MRA) of the brain showed an acute infarct at the right thalamus and an absent left internal carotid artery (ICA).Electroencephalogram (EEG) was negative.Bisoprolol was given and an Automatic Implantable Cardioverter Defibrillator (AICD) was subsequently placed.No recurrence of cardiac arrhythmia was noted on continuous cardiac telemetry monitoring during her hospitalization and on six months of follow-up.
CONCLUSION: Fatal cardiac arrhythmias, can occur in patients with  acute  thalamic  infarct  even  beyond  24  hours  in  the presence of other confounding factors despite the absence of cardiac pathology. This case showed the association of heightened  autonomic  imbalance  caused  by  an  acute stroke, decreased cerebral flow, and fatal arrhythmia. This elucidates the importance of cardiac monitoring in acute ischemic stroke. With the paucity of information on serious cardiac arrhythmia and ischemic stroke, a future study on this correlation will be useful.

Human ; Female ; Adult ; Bisoprolol ; Tachycardia, Sinus ; Ventricular Fibrillation ; Carotid Artery, Internal ; Defibrillators, Implantable ; Electric Countershock ; Arrhythmias, Cardiac ; Electrocardiography ; Death, Sudden, Cardiac ; Heart Conduction System ; Stroke ; Thalamus ; Brain ; Autonomic Nervous System ; Telemetry ; Angiography ; Hospitalization ; Survivors ; Electrolytes

OBJECTIVETo study the correlation between EEG characteristics of medial prefrontal cortex (mPFC) and drug-seeking behavior of rats with morphine dependent place preference under shuttling condition.

METHODSForty rats were randomly divided into four groups (n = 10): morphine PL group, NS PL group, morphine IL group and NS IL group. After embeding the electrode in prelimbic (PL) or infralimbic (IL) cortex of each group by brain stereotaxic operation, the model of morphine dependent conditioned place preference (CPP) in rats was established. The differences of EEG wave percentage in mPFC were telemetered and analyzed when rats shuttled before and after the model.

RESULTSAfter the model, the withdrawal symptoms were evident in morphine PL and IL group, and the activity time and distance in white box were increased obviously. Compared with control group, after the model, the EEG in morphine PL group showed that: when the rats shuttled to white box, 8 wave decreased obviously, P wave increased obviously. When the rats shuttled to black box, brain waves showed opposite changes. The EEG in morphine IL group showed that: when the rats shuttled to white box, a wave increased obviously, P and a wave decreased obviously. When the rats shuttled to black box, the brain wave had no significant differences compared with control group.

CONCLUSIONThe EEG changes are different in PL and IL cortex of morphine CPP rats under shuttling condition, and the EEG changes are also different when rats shuttling to white or black box. There is possibly different mechanism, when different drug-seeking environmental cues caused EEG changes in different regions of mPFC.

Animals ; Conditioning (Psychology) ; Cues ; Drug-Seeking Behavior ; Electroencephalography ; Morphine Dependence ; physiopathology ; Prefrontal Cortex ; physiopathology ; Rats ; Telemetry

OBJECTIVES: Although ambulance-based telemedicine has been reported to be safe and feasible, its clinical usefulness has not been well documented, and different prehospital management systems would yield different results. The authors evaluated the feasibility and usefulness of telemedicine-assisted direct medical control in the Korean emergency medical service system. METHODS: Twenty ambulances in the Busan area were equipped with a telemedicine system. Three-lead electrocardiogram, blood pressure, and pulse oximetry data from the patient and audiovisual input from the scene were transferred to a server. Consulting physicians used desktop computers and the internet to connect to the server. Both requesting emergency medical service (EMS) providers and consulting physicians were asked to fill out report forms and submit them for analysis. RESULTS: In the 41 cases in which telemedicine equipment was used, cellular phones were concomitantly used in 28 cases (68.35%) to compensate for the poor audio quality provided by the equipment. The EMS providers rated the video transmission quality with a 4-point average score (interquartile range [IQR] 2-5) on a 5-point scale, and they rated the biosignal transmission quality as 4 (IQR 3-5). The consulting physicians rated the video quality as 4 (IQR 2.5-4) and the biosignal quality as 4 (IQR 3-4). The physicians' ratings for usefulness for making diagnosis or treatment decisions did not differ significantly in relation to the method of communication used. CONCLUSIONS: Our study did not find any significant advantage of implementing telemedicine over the use of voice calls in delivering on-line medical control. More user-friendly, smaller devices with clear advantages over voice communication would be required before telemedicine can be successfully implemented in prehospital patient care.
Ambulances ; Blood Pressure ; Busan ; Cellular Phone ; Diagnosis ; Electrocardiography ; Emergency Medical Services ; Humans ; Internet ; Oximetry ; Patient Care ; Remote Consultation ; Telemedicine* ; Telemetry ; Voice

The loss of urinary bladder control/sensation, also known as urinary incontinence (UI), is a common clinical problem in autistic children, diabetics, and the elderly. UI not only causes discomfort for patients but may also lead to kidney failure, infections, and even death. The increase of bladder urine volume/pressure above normal ranges without sensation of UI patients necessitates the need for bladder sensors. Currently, a catheter-based sensor is introduced directly through the urethra into the bladder to measure pressure variations. Unfortunately, this method is inaccurate because measurement is affected by disturbances in catheter lines as well as delays in response time owing to the inertia of urine inside the bladder. Moreover, this technique can cause infection during prolonged use; hence, it is only suitable for short-term measurement. Development of discrete wireless implantable sensors to measure bladder volume/pressure would allow for long-term monitoring within the bladder, while maintaining the patient's quality of life. With the recent advances in microfabrication, the size of implantable bladder sensors has been significantly reduced. However, microfabricated sensors face hostility from the bladder environment and require surgical intervention for implantation inside the bladder. Here, we explore the various types of implantable bladder sensors and current efforts to solve issues like hermeticity, biocompatibility, drift, telemetry, power, and compatibility issues with popular imaging tools such as computed tomography and magnetic resonance imaging. We also discuss some possible improvements/emerging trends in the design of an implantable bladder sensor.
Aged ; Biocompatible Materials ; Catheters ; Child ; Hostility ; Humans ; Magnetic Resonance Imaging ; Microtechnology ; Quality of Life ; Reaction Time ; Reference Values ; Renal Insufficiency ; Sensation ; Telemetry ; Urethra ; Urinary Bladder* ; Urinary Incontinence

OBJECTIVETo investigate the changes of telemetry electrical activity in the infralimbic cortex (IL) of morphine-dependent rats with extinguished drug-seeking behavior.

METHODSSD rats were randomly divided into model group and control group and received operations of brain stereotaxic electrode embedding in the IL. The rats in the model group were induced to acquire morphine dependence and then received subsequent extinction training, and the changes of electrical activity in the IL were recorded with a physical wireless telemetry system.

RESULTSIn rats with morphine dependence, the time staying in the white box was significantly longer on days 1 and 2 after withdrawal than that before morphine injection and that of the control rats, but was obviously reduced on days 1 and 2 after extinction training to the control level. Compared with the control group, the morphine-dependent rats on day 2 following withdrawal showed significantly increased β wave and decreased δ wave when they stayed in the white box but significantly increased δ wave and decreased α wave and β wave when they shuttled from the black to the white box. On day 2 of extinction, the model rats, when staying in the white box, showed significantly decreased θ wave compared with that of the control rats group but decreased β wave and θ wave and increased δ wave compared with those in the withdrawal period. When they shuttled from black to white box, the model rats showed decreased δ wave and increased α wave and β wave compared with those in the withdrawal period.

CONCLUSIONMorphine-dependent rats have abnormal changes of electrical activity in the IL in drug-seeking extinction to affect their drug-seeking motive and inhibit the expression and maintenance of drug-seeking behaviors.

Animals ; Cerebral Cortex ; drug effects ; physiology ; Drug-Seeking Behavior ; physiology ; Electrophysiological Phenomena ; Extinction, Psychological ; Morphine ; pharmacology ; Morphine Dependence ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Telemetry

Sibutramine is an anorectic that has been banned since 2010 due to cardiovascular safety issues. However, counterfeit drugs or slimming products that include sibutramine are still available in the market. It has been reported that illegal sibutramine-contained pharmaceutical products induce cardiovascular crisis. However, the mechanism underlying sibutramine-induced cardiovascular adverse effect has not been fully evaluated yet. In this study, we performed cardiovascular safety pharmacology studies of sibutramine systemically using by hERG channel inhibition, action potential duration, and telemetry assays. Sibutramine inhibited hERG channel current of HEK293 cells with an IC50 of 3.92 muM in patch clamp assay and increased the heart rate and blood pressure (76 Deltabpm in heart rate and 51 DeltammHg in blood pressure) in beagle dogs at a dose of 30 mg/kg (per oral), while it shortened action potential duration (at 10 muM and 30 muM, resulted in 15% and 29% decreases in APD50, and 9% and 17% decreases in APD90, respectively) in the Purkinje fibers of rabbits and had no effects on the QTc interval in beagle dogs. These results suggest that sibutramine has a considerable adverse effect on the cardiovascular system and may contribute to accurate drug safety regulation.
Action Potentials ; Animals ; Blood Pressure ; Cardiovascular System ; Counterfeit Drugs ; Dogs ; Heart Rate ; HEK293 Cells ; Inhibitory Concentration 50 ; Pharmaceutical Preparations ; Pharmacology* ; Purkinje Fibers ; Rabbits ; Telemetry

OBJECTIVETo analyse the relationship between the electrical activity changes of nucleus accumbens (NAc) shell and the drug-seeking behavior by recording NAc shell electrical activity in conditioned place preference (CPP) rats induced by morphine.

METHODSForty SD rats were randomly divided into operation-only control group and the morphine-induced CPP group after stereotaxic electrode was buried on rats NAc shell and the latter group was used to establish the morphine CPP model(n = 20). A CPP video system combining with the technique of electrical activity wireless telemetry was used in the study. The NAc electrical activity from each group of rats was recorded by wireless telemetry respectively, which included staying in black or white chamber of video box, shuttling between black-white chambers and between white-black chambers. The electrical activity differences were analyzed by the percentage of each wave.

RESULTSWhen the morphine-induced rats staying in black chamber, compared with the operation-only control group, the NAc shell electrical activity showed that the percentage of 0 - 10 Hz was increased(P < 0.05), meanwhile, those of 10 - 20 Hz and 30 - 40 Hz were reduced(P < 0.05, P < 0.01); when the morphine-induced rats staying in white chamber, the NAc shell electrical activity showed that the percentage of 0 - 10 Hz and 30 - 40 Hz were increased(P < 0.05 , P < 0.01) , that of 10 - 20 Hz was reduced(P < 0.05 , P < 0. 01); when the morphine-induced rats in black- white shuttling status, the NAc shell electrical activity showed that the percentage of 0 - 10 Hz was increased(P <0.05, P <0.01), that of 10- 30 Hz was reduced( P <0.05); and in the white-black shuttling status, the electrical activity showed that the percentage of 0 - 10 Hz was reduced(P <0.05), that of 10 - 30 Hz was increased(P < 0.05) ; the electrical activity was further compared between staying status and shuttling status in the morphine-induced CPP group. There was no significant difference of electrical activity between the rats in white-black shuttling status and staying in white chamber. However, when rats in black-white shuttling status, compared with staying in black chamber, the electrical activity showed that the percentage of 0 - 10 Hz and 40 - 50 Hz were increased(P < 0.05), meanwhile, those of 10 - 20 Hz and 30 - 40 Hz were reduced(P <0.05).

CONCLUSIONThe electrical activity changes of NAc shell in morphine-induced CPP rats were different from those of the operation-only control group, and these changes might be associated to the rat's drug-seeking behavior.

Animals ; Conditioning (Psychology) ; Drug-Seeking Behavior ; Morphine ; pharmacology ; Nucleus Accumbens ; drug effects ; physiology ; Rats ; Rats, Sprague-Dawley ; Telemetry