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1.
Med Sci Monit ; 29: e942119, 2023 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-37705234

RESUMEN

BACKGROUND Post-cardiac arrest syndrome (PCAS) is a major concern and shares pathophysiology with sepsis. Sequential organ failure assessment (SOFA) scores and serum lactate levels, as suggested in the Survival Sepsis Guidelines, have shown significant predictive value for prognosis in patients with sepsis. This retrospective study aimed to evaluate combined use of the SOFA score and serum lactate measurement on survival prognosis in PCAS. MATERIAL AND METHODS Our study included patients with return of spontaneous circulation after cardiac arrest who were age >18 years and underwent targeted temperature management. The 438 patients were allocated to a surviving group and a deceased group at discharge. Multivariable regression models were used to evaluate any association with SOFA scores, serum lactate levels, and survival. To evaluate the predictive value of regression models, the area under the receiver operating characteristic curve (AUROC) was assessed. RESULTS Lower SOFA score and serum lactate level were associated with better survival rates in the post-cardiac arrest patients (SOFA score: odds ratio (OR), 0.77; 95% confidence interval (CI), 0.67-0.88; P<0.001; lactate level: OR, 0.85; 95% CI, 0.81-0.94; P<0.001). The combined model of the SOFA score and serum lactate level was superior to models including either SOFA score or serum lactate level alone in predicting survival (AUROC, 0.86 vs 0.83, P=0.028, 0.86 vs 0.81, P=0.004). CONCLUSIONS Because of the superiority of the combined model of SOFA score and serum lactate level, combining these 2 factors could improve prediction of prognosis and survival outcomes in PCAS.


Asunto(s)
Paro Cardíaco , Síndrome de Paro Post-Cardíaco , Sepsis , Humanos , Adolescente , Puntuaciones en la Disfunción de Órganos , Estudios Retrospectivos , Paro Cardíaco/complicaciones , Lactatos
3.
Am J Emerg Med ; 68: 175-178, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37030085

RESUMEN

BACKGROUND: This study aimed to investigate the association between traumatic tap and the incidence of post-dural puncture headache (PDPH) following lumbar puncture (LP) among patients who underwent LP with a primary discharge diagnosis of primary headache in the emergency department (ED). METHODS: We retrospectively reviewed the medical records of patients who visited a single tertiary ED with the symptom of a headache and underwent LP for cerebrospinal fluid (CSF) analysis between January 2012 and January 2022. Patients who met the definition of PDPH and revisited the ED or outpatient clinic within 2 weeks of discharge were included. For comparative analysis, we divided the groups according to CSF RBC counts (group 1, CSF RBC <10 cells/µL; group 2, 10-100 cells/µL; group 3, ≥100 cells/µL). The primary outcome was the difference in CSF RBC counts between the ED or outpatient clinic revisiting patients who underwent LP within 2 weeks after discharge from the ED. The secondary outcomes were the admission rate and risk factors for PDPH; sex, age, needle size, and CSF pressure. RESULTS: Data from 112 patients were collected; PDPH was reported in 39 patients (34.8%), and 40 (35.7%) patients were admitted. The median (interquartile range) CSF RBC count was 10 [2-100.8] cells/µL. One-way analysis of variance test of the mean differences among the three groups showed no differences in age, the duration of headache before LP, PLT counts, PT, or aPTT among the groups. There were differences in the number of admitted patients (30 vs. 7 vs. 3, P < 0.001) and the incidence of PDPH (29 vs. 6 vs. 4, P < 0.003). In the comparison of the PDPH and non-PDPH groups, there were differences in age (28.7 ± 8.4 years vs. 36.9 ± 18.4 years, P = 0.01) and the admission rate (85% vs. 9%, P < 0.001). CONCLUSIONS: Notably, our results suggest that traumatic LP may be an unexpected factor in reducing the occurrence rate of PDPH. Consequently, the admission rate for PDPH was significantly reduced among patients with traumatic LP and those with primary headaches. In this study, we collected and analyzed the data from a relatively small sample size of 112 patients. Further studies are needed to evaluate the relationship between traumatic LP and PDPH.


Asunto(s)
Cefalea Pospunción de la Duramadre , Punción Espinal , Humanos , Adulto Joven , Adulto , Punción Espinal/efectos adversos , Estudios Retrospectivos , Cefalea/epidemiología , Cefalea/etiología , Cefalea Pospunción de la Duramadre/epidemiología , Servicio de Urgencia en Hospital
4.
J Korean Med Sci ; 38(3): e18, 2023 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-36647218

RESUMEN

BACKGROUND: The coronavirus disease 2019 (COVID-19) omicron (B.1.1.529) variant reduced the risk of severe disease compared with the original strain and other variants, but it appeared to be highly infectious, which resulted in an exponential increase in confirmed cases in South Korea. As the number of confirmed cases increased, so did the number of pediatric patients' hospitalization. This study aims to evaluate the frequency and clinical features of febrile seizure associated with the COVID-19 omicron variant in children. METHODS: We retrospectively reviewed the medical records of children aged under 18 years with febrile seizure who were tested for COVID-19 from February 2020 to April 2022 at Ajou University Hospital, South Korea. Based on the dominant variants, we divided the period into the pre-omicron (from February 2020 to December 2021) and omicron periods (from January 2022 to April 2022) and compared the clinical characteristics between the two. Also, we compared the clinical characteristics of febrile seizure between COVID-19 positive and negative group during the omicron period. RESULTS: Among the 308 children, 211 patients (9.2 patients/months) and 97 patients (24.3 patients/months) were grouped into pre-omicron and omicron periods, respectively. Compared with the pre-omicron period, patients in the omicron period showed significantly higher mean age (pre-omicron vs. omicron, 22.0 vs. 28.0 months; P = 0.004) and COVID-19 positive results (pre-omicron vs. omicron, 0.5% vs. 62.9%; P < 0.001). As the COVID-19 confirmed cases in the omicron period increased, the number of COVID-19 associated febrile seizure also increased. In the omicron period, 61 children were confirmed to be positive for COVID-19, and COVID-19 positive group showed statistically significant higher mean age (positive vs. negative, 33.0 vs. 23.0 months; P = 0.003) and peak body temperature than the negative group (positive vs. negative, 39.1°C vs. 38.6°C; P = 0.030). Despite the lack of significance, COVID-19 positive group showed longer seizure time, multiple seizure episodes, and higher prevalence of complex febrile seizure. CONCLUSION: The frequency of COVID-19 associated febrile seizure increased in the omicron periods. In addition, in this period, children with febrile seizure diagnosed with COVID-19 had a higher mean age and higher peak body temperature.


Asunto(s)
COVID-19 , Convulsiones Febriles , Humanos , Niño , Adolescente , Convulsiones Febriles/diagnóstico , Convulsiones Febriles/epidemiología , Estudios Retrospectivos , COVID-19/epidemiología , SARS-CoV-2 , Fiebre
5.
Am J Emerg Med ; 63: 55-60, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36327750

RESUMEN

BACKGROUND: To evaluate the relationship between body weight and the success rate of supraventricular tachycardia (SVT) termination after an initial 6-mg adenosine administration. METHODS: This retrospective observational study was conducted with medical records of patients who visited a single tertiary emergency department and underwent an electrophysiologic study with an SVT diagnosis. Patients under 18 years of age or those with SVT aberrancy, recurring SVT after radiofrequency catheter ablation, premedication of non-dihydropyridine calcium channel blocker, and signs of shock were excluded. RESULTS: Data from 124 patients were collected. There were 69 women (55.6%); mean age, 49.7 years. The mean weight and height were 66.8 kg and 164.8 cm, respectively. Adenosine dose was 0.09 mg/kg. For the first sinus conversion (SC) success group (83 patients, 67%), the mean weight, height, and adenosine dose were 61.0 ± 11.5 kg, 161.9 ± 8.1 cm, and 0.10 ± 0.02 mg/kg. For the first SC failure group, these values were 78.4 ± 17.0 kg, 170.7 ± 8.9 cm, and 0.079 ± 0.02 mg/kg, respectively. To evaluate factors associated with the first SC, we performed bivariate logistic regression with weight (odds ratio [OR]: 1.093; 95% confidence interval [CI]: 1.045-1.144; P < 0.001) and height (OR: 1.071; 95% CI: 1.008-1.138; P = 0.027). Receiver operating characteristics curves and the cut-off values for adenosine dose and weight were 0.90 mg/kg and 66.5 kg with 71.1% sensitivity and 73.2% specificity (area under the curve: 0.814; 95% CI: 0.73-0.90; P < 0.001). CONCLUSION: Weight and height were significant predictors of the first SC success rate among SVT patients. Consequentially, it is necessary to consider other adenosine administration methods, including increasing the initial drug dose or changing the flushing strategy after adenosine injection.


Asunto(s)
Adenosina , Humanos , Femenino , Adolescente , Persona de Mediana Edad , Adenosina/uso terapéutico , Peso Corporal
6.
J Korean Med Sci ; 37(47): e337, 2022 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-36472085

RESUMEN

BACKGROUND: We aimed to investigate changes in the clinical characteristics of pediatric poisoning patients who visited the emergency department (ED) before and during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: Poisoning cases below age 18 who visited the ED from January 2018 to December 2021 were retrospectively analysed. The study period was then divided into pre-COVID-19 and COVID-19 pandemic to compare poisoning patterns. RESULTS: During the study period, 86,153 visits to the pediatric ED had been recorded, with 625 patients being included the final analysis. During the COVID-19 period, the proportion of poisoned patients increased from 0.62% to 0.98%. The average age of the patients was higher in the COVID-19 period, with 53.4% of the cases being intentional (pre-COVID-19, 32.5%; P < 0.001). Moreover, 70.4% of poisoning cases during the COVID-19 period were caused by drugs (pre-COVID-19, 60.6%; P = 0.038). More patients underwent decontamination and laboratory investigation during the COVID-19 period than during the previous period (P = 0.007 and P < 0.001, respectively). The length of ED stay and the proportion of hospitalisation were significantly greater during the COVID-19 period. After analysing accidental poisoning cases, we found that antipyretics/nonsteroidal anti-inflammatory drugs and respiratory drugs were more common in the pre-COVID-19 group, whereas iron/vitamins, cardiovascular drugs and hormones were more common in the COVID-19 group. After analysing intentional poisoning cases, we found that 73.6% and 76.4% of the patients in the pre-COVID-19 and COVID-19 group had a history of psychiatric disease, respectively. Although no difference was observed in the frequency of previous first suicide attempts, 19.0% of the patients in the COVID-19 group attempted suicide more than three times. CONCLUSION: During the COVID-19 pandemic, intentional poisoning cases, especially in adolescence, increased and were treated more. Many of the patients with intentional poisoning had a history of mental illness or suicide in the past. Therefore, it seems that policy consideration for mentally vulnerable adolescents during this new pandemic period is necessary.


Asunto(s)
COVID-19 , Pandemias , Adolescente , Niño , Humanos , COVID-19/epidemiología , Estudios Retrospectivos , Intento de Suicidio/psicología , Servicio de Urgencia en Hospital
7.
J Clin Med ; 11(13)2022 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-35806880

RESUMEN

Seizure is a common neurological presentation in patients visiting the emergency department (ED) that requires time for evaluation and observation. Timely decision and disposition standards for seizure patients need to be established to prevent overcrowding in the ED and achieve patients' safety. Here, we conducted a retrospective cohort study to predict early seizure recurrence in the ED (ES-RED). We randomly assigned 688 patients to the derivation and validation cohorts (2:1 ratio). Prediction equations extracted routine clinical and laboratory information from EDs using logistic regression (Model 1) and machine learning (Model 2) methods. The prediction equations showed good predictive performance, the area under the receiver operating characteristics curve showing 0.808 in Model 1 [95% confidential interval (CI): 0.761-0.853] and 0.805 in Model 2 [95% CI: 0.747-0.857] in the derivation cohort. In the external validation, the models showed strong prediction performance of 0.739 [95% CI: 0.640-0.824] in Model 1 and 0.738 [95% CI: 0.645-0.819] in Model 2. Intriguingly, the lowest quartile group showed no ES-RED after 6 h. The ES-RED calculator, our proposed prediction equation, would provide strong evidence for safe and appropriate disposition of adult resolved seizure patients from EDs, reducing overcrowding and delays and improving patient safety.

9.
BMC Pediatr ; 21(1): 501, 2021 11 10.
Artículo en Inglés | MEDLINE | ID: mdl-34758763

RESUMEN

BACKGROUND: In mildly to moderately dehydrated patients with acute gastroenteritis (AGE), oral rehydration therapy (ORT) is the treatment of choice. Though ondansetron is a very effective antiemetics and leads to succeed ORT, there have been reports QT prolongation in patients using it. We investigated the effect of oral ondansetron on QT interval in mildly to moderately dehydrated children with AGE. METHODS: This retrospective observational study was conducted in a single pediatric emergency department (ED) of a tertiary university hospital. We collected the medical records of patients with a primary diagnosis of AGE who received oral ondansetron and underwent an electrocardiogram between January 2017 and June 2018. A pediatric emergency physician calculated the corrected QT interval (QTc) by Bazett's method, and the calculations were reviewed by a pediatric cardiologist. QTc values before (preQTc) and after (postQTc) ondansetron administration were analyzed. ΔQTc was calculated as the change from preQTc to postQTc. We also investigated any cardiac complications from oral ondansetron. RESULTS: Total 80 patients were included. The mean age of the patients was 53.31 ± 32.42 months, and 45% were male. The mean dose of oral ondansetron was 0.18 ± 0.04 mg/kg. The mean interval from administration of ondansetron to performance of the electrocardiogram was 65 ± 26 min. The mean preQTc was 403.3 ± 24.0 ms, and the mean postQTc was 407.2 ± 26.7 ms. Two patients had a preQTc ≥460 ms, and one patient had a postQTc ≥460 ms. ΔQTc was ≥30 ms in seven patients (8.8%). No ΔQTc was ≥60 ms. No pre- or postQTc was ≥500 ms. No patient had a fatal cardiac arrhythmia after taking ondansetron. CONCLUSION: Oral administration of a single dose of ondansetron in children with AGE did not cause high-risk QTc prolongation or fatal arrhythmia.


Asunto(s)
Antieméticos , Gastroenteritis , Síndrome de QT Prolongado , Antieméticos/efectos adversos , Niño , Preescolar , Electrocardiografía , Gastroenteritis/complicaciones , Gastroenteritis/tratamiento farmacológico , Humanos , Lactante , Síndrome de QT Prolongado/tratamiento farmacológico , Masculino , Ondansetrón/efectos adversos , Vómitos
10.
Medicine (Baltimore) ; 100(40): e27485, 2021 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-34622880

RESUMEN

ABSTRACT: Pharmaceutical poisoning in children is almost unintentional and there are various types of drug out of curiosity. Understanding the attractive features and formulation of drugs related to poisoning in younger children may be helpful in treatment and prevention of poisoning. To investigate the impact of drug formulation on outcomes of pharmaceutical poisoning in young children.We retrospectively reviewed the data of pharmaceutical exposures among children who were registered in a Korean 23-center, emergency department (ED) based registry from 2011 to 2016. Our study was conducted on preschool children aged 0 to 7 years. According to the formulation and category of the ingested drugs, the exposures were divided into the "tablet and capsule (TAC)" and "syrup" groups. In the TAC group, we additionally recorded data on the shape, color, and size of the drugs. The ED outcomes, such as hospitalization and length of stay, were compared between the 2 groups.Among the 970 enrolled exposures, 674 (69.5%) were classified into the TAC group. In this group, hormones/hormone antagonists (18.5%) were the most commonly ingested, followed by central nervous system drugs (17.1%). In the syrup group, antihistamines (28.4%) were the most commonly ingested, followed by respiratory drugs (24.3%). The TAC group showed a higher hospitalization and transfer rate to tertiary centers than the counterpart (TAC, 18.0% vs syrup, 11.5%, P = .03) without a significant difference in the length of stay (TAC, 173.5 minutes [interquartile range, 95.0-304.0] vs syrup, 152.5 [77.5-272.0]; P = .08). No in-hospital mortality occurred in the exposures. Round-shaped and chromatic TACs, accounting for 91.7% (618) and 56.1% (378), respectively, were more commonly ingested. The median size of the TACs was less than 1.0 cm.Young children who visited the ED ingested TACs more frequently than syrups, particularly small, round-shaped, or chromatic drugs, leading to a higher hospitalization rate. Our findings can contribute to prevention strategies and safety education on childhood drug poisoning.


Asunto(s)
Formas de Dosificación , Composición de Medicamentos/estadística & datos numéricos , Intoxicación/epidemiología , Medicamentos bajo Prescripción/envenenamiento , Cápsulas , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , República de Corea , Estudios Retrospectivos , Comprimidos
11.
Artículo en Inglés | MEDLINE | ID: mdl-34444353

RESUMEN

This study estimated tourists' willingness to pay (WTP) for tourist sites or facilities in the prolonged COVID-19 pandemic by applying the dichotomous choice-contingent valuation method to two different tourism destination types. A survey was conducted among domestic tourists in South Korea who had visited destinations within the last six months. We conducted a logistic regression with 1283 effective samples. The results showed differences in tourists' WTP, depending on type, and the factors affecting WTP differed. Tourists with higher tourism attitude and knowledge of tourism risk exhibited a higher WTP. Tourists with higher perceived risk of infectious disease exhibited less WTP.


Asunto(s)
COVID-19 , Pandemias , Actitud , Humanos , República de Corea/epidemiología , SARS-CoV-2
13.
Disabil Health J ; 13(4): 100931, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32327387

RESUMEN

BACKGROUND: Approximately, 600,000 people in South Korea have registered as people with either visual or hearing impairment or both. Individuals with sensory impairments are more likely to have limited physical and social functioning, which consequently affected their health, well-being and life satisfaction. While diverse elements were considered as critical determinants of life satisfaction among individuals with sensory impairments, only few studies examined the relationships between life domains and life satisfaction of the population. OBJECTIVES: This study investigated the relationships between life domains and life satisfactions among Korean individuals with sensory impairments. METHODS: This study used 2015 national data from Korea to explore the relationships across different age groups. A total of 965 participants were selected, and they were divided into three groups: (a) middle aged group (MAG; 54 and below, 35.2%), (b) late-middle aged group (L-MAG; 55-64; 35.2%), and (c) older adult group (OAG; 65 and older; 29.5%). Demographic variables (e.g., perceived socioeconomic status, the severity of disabilities), the satisfaction of seven life domains, and the overall life satisfaction were measured. RESULTS: Although most of the life domains were significant predictors of overall life satisfaction, the leisure domain was the strongest determinant of the overall life satisfaction to MAG and OAG and the second strongest predictor to L-MAG. CONCLUSION: This study highlights the importance of leisure for quality of life of individuals with sensory impairments and suggests an implication to researchers and practitioners to increase accessibility for individuals with sensory impairments to leisure facilities and programs.


Asunto(s)
Pueblo Asiatico/psicología , Personas con Discapacidad/psicología , Pérdida Auditiva/psicología , Satisfacción Personal , Calidad de Vida/psicología , Trastornos de la Sensación/psicología , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Pueblo Asiatico/estadística & datos numéricos , Personas con Discapacidad/estadística & datos numéricos , Femenino , Humanos , Longevidad , Masculino , Persona de Mediana Edad , República de Corea
14.
BMC Pediatr ; 19(1): 335, 2019 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-31521164

RESUMEN

BACKGROUND: We aimed to study the prevalence of enterovirus (EV) meningitis without the presence of cerebrospinal fluid (CSF) pleocytosis and identify patient factors and clinical features associated with it. METHODS: This was a retrospective analysis of patients aged < 18 years old who were diagnosed with EV meningitis by CSF reverse-transcriptase polymerase chain reaction (RT-PCR) testing between January 2015 and December 2016. Clinical variables were compared with regard to the presence of CSF pleocytosis. RESULTS: A total of 305 patients were enrolled in study; 169 (55.4%) had no pleocytosis. Patients without pleocytosis were younger (median age 2 months vs. 67.0 months, p < 0.01) and had lower white blood cell (WBC) count (median, 8600/mm3 vs. 10,300/mm3, p < 0.01). Also absolute neutrophil (ANC) count were lower than pleocytosis group (median, 4674/mm3 vs. 7600/mm3, p < 0.01). Comparing three age groups, CSF apleocytosis was present in 106 of 128 patients (82.8%) aged ≤3 months, 7 of 13 patients (53.8%) aged 3 months-3 years and 56 of 164 patients (34.1%) aged > 3 years. Younger age groups had higher prevalence of CSF apleocytosis (p < 0.01). In patients aged ≤3 months, 94.5% underwent lumbar puncture within 24 h of symptom onset. The frequency of not having pleocytosis was higher than the frequency of having pleocytosis during peak EV infection prevalent months (summer and fall) (p < 0.01). CONCLUSION: This study shows that EV meningitis in young infants, with early lumbar puncture, or occurring during peak EV meningitis prevalent seasons cannot be solely excluded by pleocytosis. Also, a confirmation test for EV meningitis should be performed using RT-PCR.


Asunto(s)
Infecciones por Enterovirus/líquido cefalorraquídeo , Leucocitosis/líquido cefalorraquídeo , Meningitis Viral/líquido cefalorraquídeo , Factores de Edad , Niño , Preescolar , Infecciones por Enterovirus/complicaciones , Infecciones por Enterovirus/diagnóstico , Femenino , Cefalea/etiología , Humanos , Lactante , Recuento de Leucocitos , Leucocitosis/complicaciones , Leucocitosis/epidemiología , Masculino , Meningitis Viral/complicaciones , Meningitis Viral/diagnóstico , Neutrófilos , Prevalencia , República de Corea/epidemiología , Estudios Retrospectivos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Estaciones del Año , Punción Espinal , Vómitos/etiología
15.
Micromachines (Basel) ; 10(10)2019 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-31557853

RESUMEN

In this article, we report on a biomimetic tactile sensor that has a surface kinetic interface (SKIN) that imitates human epidermal fingerprint ridges and the epidermis. The SKIN is composed of a bilayer polymer structure with different elastic moduli. We improved the tactile sensitivity of the SKIN by using a hard epidermal fingerprint ridge and a soft epidermal board. We also evaluated the effectiveness of the SKIN layer in shear transfer characteristics while varying the elasticity and geometrical factors of the epidermal fingerprint ridges and the epidermal board. The biomimetic tactile sensor with the SKIN layer showed a detection capability for surface structures under 100 µm with only 20-µm height differences. Our sensor could distinguish various textures that can be easily accessed in everyday life, demonstrating that the sensor may be used for texture recognition in future artificial and robotic fingers.

16.
Nanotechnology ; 30(40): 405203, 2019 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-31284280

RESUMEN

We investigated the performance improvement of tin disulfide channel transistors by graphene contact configurations. From its two-dimensional nature, graphene can make electric contacts only at the outermost layers of the channel. For intralayer current flow, two graphene flakes are contacted at the channel's top or bottom layer. For interlayer current flow, one flake is contacted at the top and bottom of each layer. We compared the transistor performance in terms of current magnitude, mobility, and subthreshold swing between the configurations. From such observations, we deduced that device characteristics depend on resistivity or doping level of individual graphene flakes. We also found that interlayer flow excels in the on-current magnitude and the mobility, and that top-contact configuration excels in the subthreshold swing.

17.
Sensors (Basel) ; 19(6)2019 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-30875874

RESUMEN

In this article, we report on a highly sensitive tactile shear sensor that was able to detect minute levels of shear and surface slip. The sensor consists of a suspended elastomer diaphragm with a top ridge structure, a graphene layer underneath, and a bottom substrate with multiple spatially digitized contact electrodes. When shear is applied to the top ridge structure, it creates torque and deflects the elastomer downwards. Then, the graphene electrode makes contact with the bottom spatially digitized electrodes completing a circuit producing output currents depending on the number of electrodes making contact. The tactile shear sensor was able to detect shear forces as small as 6 µN, detect shear direction, and also distinguish surface friction and roughness differences of shearing objects. We also succeeded in detecting the contact slip motion of a single thread demonstrating possible applications in future robotic fingers and remote surgical tools.

19.
Sci Rep ; 7: 39966, 2017 01 09.
Artículo en Inglés | MEDLINE | ID: mdl-28067288

RESUMEN

Ultrafast electron-based coherent radiation sources, such as free-electron lasers (FELs), ultrafast electron diffraction (UED) and Thomson-scattering sources, are becoming more important sources in today's ultrafast science. Photocathode laser is an indispensable common subsystem in these sources that generates ultrafast electron pulses. To fully exploit the potentials of these sources, especially for pump-probe experiments, it is important to achieve high-precision synchronization between the photocathode laser and radio-frequency (RF) sources that manipulate electron pulses. So far, most of precision laser-RF synchronization has been achieved by using specially designed low-noise Er-fibre lasers at telecommunication wavelength. Here we show a modular method that achieves long-term (>1 day) stable 10-fs-level synchronization between a commercial 79.33-MHz Ti:sapphire laser oscillator and an S-band (2.856-GHz) RF oscillator. This is an important first step toward a photocathode laser-based femtosecond RF timing and synchronization system that is suitable for various small- to mid-scale ultrafast X-ray and electron sources.

20.
J Environ Sci (China) ; 26(6): 1249-59, 2014 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-25079833

RESUMEN

A credible accounting of national and regional inventories for the greenhouse gas (GHG) reduction has emerged as one of the most significant current discussions. This article assessed the regional GHG emissions by three categories of the waste sector in Daejeon Metropolitan City (DMC), Korea, examined the potential for DMC to reduce GHG emission, and discussed the methodology modified from Intergovernmental Panel on Climate Change and Korea national guidelines. During the last five years, DMC's overall GHG emissions were 239 thousand tons CO2 eq./year from eleven public environmental infrastructure facilities, with a population of 1.52 million. Of the three categories, solid waste treatment/disposal contributes 68%, whilst wastewater treatment and others contribute 22% and 10% respectively. Among GHG unit emissions per ton of waste treatment, the biggest contributor was waste incineration of 694 kg CO2 eq./ton, followed by waste disposal of 483 kg CO2 eq./ton, biological treatment of solid waste of 209 kg CO2 eq./ton, wastewater treatment of 0.241 kg CO2 eq./m(3), and public water supplies of 0.067 kg CO2 eq./m(3). Furthermore, it is suggested that the potential in reducing GHG emissions from landfill process can be as high as 47.5% by increasing landfill gas recovery up to 50%. Therefore, it is apparent that reduction strategies for the main contributors of GHG emissions should take precedence over minor contributors and lead to the best practice for managing GHGs abatement.


Asunto(s)
Contaminación del Aire/estadística & datos numéricos , Gases , Contaminación del Aire/análisis , Contaminación del Aire/prevención & control , Efecto Invernadero , República de Corea , Administración de Residuos
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